Updated on 2022/06/01

写真a

 
TOKU Yuhki
 
Organization
Graduate School of Engineering Micro-Nano Mechanical Science and Engineering 1 Lecturer
Graduate School
Graduate School of Engineering
Undergraduate School
School of Engineering Mechanical and Aerospace Engineering
Title
Lecturer
Contact information
メールアドレス
External link

Degree 1

  1. Doctor (Engineering) ( 2014.3   Akita University ) 

Research Interests 1

  1. Nanomaterials

Research Areas 3

  1. Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Mechanics of materials and materials

  2. Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Manufacturing and production engineering

  3. Manufacturing Technology (Mechanical Engineering, Electrical and Electronic Engineering, Chemical Engineering) / Mechanics of materials and materials

Research History 9

  1. Nagoya University   Graduate School of Engineering Micro-Nano Mechanical Science and Engineering 1   Lecturer

    2018.10

  2. Nagoya University   Graduate School of Engineering Micro-Nano Mechanical Science and Engineering 1   Assistant Professor

    2017.4 - 2018.9

  3. Nagoya University   Graduate School of Engineering Department of Mechanical Science and Engineering Advanced Material and Manufacturing   Assistant Professor

    2014.10 - 2017.3

  4. 日本学術振興会 特別研究員PD

    2014.4 - 2014.9

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    Country:Japan

  5. 日本学術振興会 特別研究員PD

    2014.4 - 2014.9

  6. Japan Society for Promotion of Science

    2014.4 - 2014.9

  7. 日本学術振興会 特別研究員DC2

    2013.4 - 2014.3

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    Country:Japan

  8. 日本学術振興会 特別研究員DC2

    2013.4 - 2014.3

  9. Japan Society for Promotion of Science

    2013.4 - 2014.3

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Education 1

  1. Akita University

    2011.4 - 2014.3

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    Country: Japan

Professional Memberships 1

  1. 日本機械学会

Committee Memberships 1

  1. 日本機械学会   2020年次大会実行委員会委員  

    2020.9   

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    Committee type:Academic society

Awards 3

  1. 日本機械学会東海支部特別功労賞

    2021.3   日本機械学会東海支部  

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    Award type:Award from Japanese society, conference, symposium, etc. 

  2. 三浦賞

    2011.3   機械学会  

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    Country:Japan

  3. 独創研究学生賞(大学院修士の部)

    2010.3   機械学会東北支部  

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    Country:Japan

 

Papers 36

  1. Rapid anisotropy recovery in deformed FCC metals by high-density pulsed electric current treatment Reviewed

    Gu Shaojie, Cui Yi, Yoon Sungmin, Wang Zizheng, Kimura Yasuhiro, Toku Yuhki, Ju Yang

    VACUUM   Vol. 197   2022.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Vacuum  

    The {101} texture of deformed face-centered cubic metals, such as 316 stainless steel and Ni-based alloy Inconel 718, was successfully alleviated by high-density pulsed electric current (HDPEC) treatment. Furthermore, the deformed grains recovered after the HDPEC treatment. The HDPEC induced the rapid dislocation motion and grain refinement that resulted in random grain orientation and equiaxed grain morphology, which led to anisotropy recovery in the deformed metals. This method provides a promising way to modify the microstructure of materials with short time and low cost, after forming or during service.

    DOI: 10.1016/j.vacuum.2021.110855

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    Scopus

  2. Improvement of low-cycle fatigue life of austenitic stainless steel by multiple high-density pulsed electric currents Reviewed

    Sungmin Yoon, Yi Cui, Yasuhiro Kimura, Shaojie Gu, Yuhki Toku, Yang Ju

    International Journal of Fatigue   Vol. 156   page: 106639 - 106639   2022.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Elsevier {BV}  

    DOI: 10.1016/j.ijfatigue.2021.106639

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  3. Relief of strain hardening in deformed Inconel 718 by high-density pulsed electric current Reviewed

    Shaojie Gu, Yi Cui, Yasuhiro Kimura, Yuhki Toku, Yang Ju

    Journal of Materials Science   Vol. 56 ( 29 ) page: 16686 - 16696   2021.10

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s10853-021-06344-9

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    Other Link: https://link.springer.com/article/10.1007/s10853-021-06344-9/fulltext.html

  4. Nanotwinning and tensile behavior in cold-welded high-entropy-alloy nanowires Reviewed International journal

    Yi Cui, Yuhki Toku, Yang Ju

    Nanotechnology   Vol. 32 ( 31 ) page: 315716 - 315716   2021.7

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:{IOP} Publishing  

    Since the fabrication technique for high-entropy alloy (HEA) nanowires/nanopillars is still in its infancy, neither experimental nor modeling analyses of their cold-welding performance have been reported. Based on insights accumulated in our previous experiments and simulations regarding cold-welded metallic nanowires, in this study, the cold-welding performance of HEA nanowires is probed by atomistic simulations. Among different materials, our simulations reveal that extensively twinned structures are formed in CoCrMnFeNi samples, but not in CoCrCuFeNi or Ni samples. The larger fracture strain in certain HEAs is due to the improved ductility around the fracturing area as well as multiple twinning. Unlike in Ni samples, the fracture strains in HEA samples, regardless of being cuboid or cylindrical, are improved by shrinking the sample size. Among different orientations, the [010]-direction monocrystalline nanowires fail at a strain over 0.6, which is almost double that of the [111] direction. The fracture strains in polycrystalline HEA samples are, on average, larger than those in polycrystalline Ni samples. Furthermore, fracture strains in randomly generated polycrystalline HEA samples are more predictable than those in polycrystalline Ni samples with identical grain configurations. As previously reported, dislocation emission is still a prerequisite to fracture in all cold-welded samples.

    DOI: 10.1088/1361-6528/abf7eb

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    PubMed

  5. Non-contact local conductivity measurement of metallic nanowires based on semi-near-field reflection of microwave atomic force microscopy Reviewed

    Bo Tong, Takahiro Hirabayashi, Yuhki Toku, Yasuyuki Morita, Yang Ju

    APPLIED PHYSICS EXPRESS   Vol. 14 ( 6 )   2021.6

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:IOP PUBLISHING LTD  

    In this study, a non-contact and quantitative evaluation method was developed to measure the conductivity of metallic nanowires at nanometer-scale resolution. Using a coaxial probe, microwave images and topographical images were simultaneously obtained for three nanowires via microwave atomic force microscopy (M-AFM). A semi-near-field model was established to describe the distribution of the electric field between the probe and the sample. Based on this model, the local conductivities of metallic nanowires on the nanometer scale were quantitatively evaluated in a single scan, using a metal strip substrate to calibrate the reflected signal.

    DOI: 10.35848/1882-0786/abf444

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  6. Quantitative evaluation of local permittivity of semiconductor nanomaterials using microwave atomic force microscopy Reviewed

    Minji Zhao, Bo Tong, Yasuhiro Kimura, Yuhki Toku, Yasuyuki Morita, Yang Ju

    Applied Physics Letters   Vol. 118 ( 19 ) page: 193103   2021.5

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:AMER INST PHYSICS  

    In this paper, we report a non-contact and quantitative method to evaluate the permittivity of semiconductor nanomaterials. A microwave atomic force microscopy (M-AFM) was used to obtain the topography and microwave images of nanomaterials in one scanning process. Morphology and microwave images of ZnO and CuO nanowires, and SnO2 nanobelts with high spatial resolution were obtained in the non-contact mode of M-AFM. The local relative permittivity of these one-dimensional metal oxide nanomaterials was quantitatively evaluated.

    DOI: 10.1063/5.0049619

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  7. Preferential growth of specific crystal planes based on the dimension control of single crystal SnO<inf>2</inf> nanobelts Reviewed International journal

    Toku Y.

    Materials Letters   Vol. 285   2021.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.matlet.2020.129121

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  8. The deformation mechanism in cold-welded gold nanowires due to dislocation emission Reviewed International journal

    Cui Y.

    Computational Materials Science   Vol. 188   2021.2

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.commatsci.2020.110214

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  9. Evaluation of Electric Current-Induced Improvement of Fracture Characteristics in SUS316 International journal

    Sungmin Yoon, Yasuhiro Kimura, Yi Cui, Yuhki Toku, Yang Ju

    MATERIALS TRANSACTIONS   Vol. 62 ( 6 ) page: 748 - 755   2021

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:JAPAN INST METALS & MATERIALS  

    The application of high-density pulsed electric current (HDPEC) is one of the effective methods for the modification of material properties in metals. To evaluate fracture behavior modified by HDPEC, critical fracture parameters such as fracture strength, fracture toughness, and fracture profile of crack tip are important criteria. This work investigates the finite element analysis (FEA) based evaluation of improved fracture characteristics by the application of HDPEC in a SUS 316 austenite stainless steel. Tensile tests were first conducted to deduce the modified material properties with different conditions of HDPEC. A series of theoretical considerations was employed to estimate the modified fracture toughness. The relationship between critical fracture strength and critical crack length was numerically determined based on the estimated fracture toughness. The results in FEA showed that critical von Mises stress on the singularity at the crack tip increases as the effect of HDPEC increases. The evolution of increased fracture toughness with respect to conditions of HDPEC was specified. Crack opening profiles were simulated to assist the explanation. The evaluation of fracture parameters in this study proposes that the modified material properties by HDPEC play a positive role to resist crack propagation.

    DOI: 10.2320/matertrans.MT-M2020333

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    CiNii Research

  10. Assessment of creep behavior using a damage-coupled model for martensitic stainless steel

    YOON Sungmin, KIMURA Yasuhiro, TOKU Yuhki, JU Yang, PARK Soojeong, KIM Yunhae

    Mechanical Engineering Journal   Vol. 8 ( 5 ) page: 21-00178 - 21-00178   2021

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:The Japan Society of Mechanical Engineers  

    <p>In this study, the Liu–Murakami (LM) creep damage-coupled model was considered to evaluate the creep properties of martensitic stainless steel. The degree of creep damage was examined at two temperatures (565 ℃ and 593 ℃) to assess mechanically and thermally activated processes. A series of high applied stresses (applied stress/ultimate strength > 0.5) was considered for accelerated creep loadings. A full set of creep constants was determined by combining the Norton and LM models. Constitutive equations were used to quantitatively estimate experimental creep curves. The variation in creep constants was discussed based on stress sensitivity, such as stress triaxiality and applied stress, depending on the power of stress. The creep strain–time curves were successfully estimated. The comparison between the experimental and analytical results was in good agreement in the tertiary regime. In addition, the compensation of the two applied temperatures provides a supplementary explanation of the relationship between the ultimate strength and rupture time in terms of temperature sensitivity. The analytical results show that different applied stresses and temperatures could be compensated to characterize the creep behavior of the material. Thus, the creep strain–time and creep strain rate–certain rupture time curves were finally achieved. The analytical process in this study provides a laboratory-scale assessment of creep properties using the accelerated creep test and LM model.</p>

    DOI: 10.1299/mej.21-00178

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    CiNii Research

  11. True origin of the size effect in cold-welded metallic nanocrystals Reviewed

    Cui Y.

    International Journal of Mechanical Sciences   Vol. 187   2020.12

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.ijmecsci.2020.106102

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  12. High-strain-rate void growth in high entropy alloys: Suppressed dislocation emission = suppressed void growth Reviewed International journal

    Yi Cui, Yuhki Toku, Yasuhiro Kimura, Yang Ju

    Scripta Materialia   Vol. 185   page: 12 - 18   2020.8

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Elsevier {BV}  

    DOI: 10.1016/j.scriptamat.2020.03.056

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  13. Fabrication of γ-Fe<sub>2</sub>O<sub>3</sub> Nanowires from Abundant and Low-cost Fe Plate for Highly Effective Electrocatalytic Water Splitting. Reviewed

      Vol. 10 ( 1 ) page: 5407   2020.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41598-020-62259-6

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  14. Adhesion Properties of Nanowire Surface Fastener Reviewed

    Toku Y., Ju Y.

    MHS 2019 - 30th 2019 International Symposium on Micro-NanoMechatronics and Human Science     2019.12

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:MHS 2019 - 30th 2019 International Symposium on Micro-NanoMechatronics and Human Science  

    The power devices that are attracting attention in the recent development of electric vehicles, specifically, SiC and GaN power devices (power semiconductors) are expected as key technologies for the 21st century because of high current control and high-frequency operation. However, because of the operating temperature exceeds 300 degrees due to high power, thermal damage on the mounting part of the electronic package cannot be prevented by the present solder technique. We recently developed a metallic nanowire surface fastener (NSF) to resolve the abovementioned problems (Fig. 1). This fastener can be used to connect electronic components on a substrate at room temperature using the van der Waals force between each nanowire. The NSF would be expected to apply huge filed such as wearable devices, assembling of power devices in the inverter of electronic vehicle. This study demonstrates a 64-pin NSF that behaves like a ball grid array for application to actual electronic devices. Additionally, we demonstrate the fabrication of NSF on the flexible substrate. Through the comparison of above both, the adhesion mechanism of NSF is discussed in this present study. We also introduce how to control the adhesion morphology to improve the adhesion strength, electronic conductivity, and thermal conductivity of the NSF.

    DOI: 10.1109/MHS48134.2019.9249283

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  15. The optimal mechanical condition in stem cell-to-tenocyte differentiation determined with the homogeneous strain distributions and the cellular orientation control. Reviewed International journal

    Yasuyuki Morita, Toshihiro Sato, Kouji Higashiura, Yusho Hirano, Fuga Matsubara, Kanau Oshima, Koji Niwa, Yuhki Toku, Guanbin Song, Qing Luo, Yang Ju

    Biology open   Vol. 8 ( 5 )   2019.5

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    Language:English   Publishing type:Research paper (scientific journal)  

    In tendon tissue engineering, mechanical stimulus-induced differentiation is one of the most attractive techniques for stem cell-to-tenocyte differentiation in terms of cost, safety and simplicity. However, the most effective strain amplitude for differentiation using cyclic stretching remains unknown. Existing studies have not constrained cell reorientation behavior during cyclic stretching, resulting in uncertainty regarding the loads experienced by cells. In addition, strain distribution homogeneity of the culture membrane is important. Here, we improved the strain distribution uniformity of the membrane and employed a microgrooved membrane to suppress cell reorientation. Then we evaluated the most effective strain amplitude (0, 2, 4, 5, 6, or 8%) for the differentiation of mesenchymal stem cells into tenocytes by measuring mRNA expression levels. The maximum expression of all tenogenic markers was observed at a 5% strain. These results contribute to tendon tissue engineering by clarifying the most effective strain amplitude during tenogenic differentiation induction using cyclic stretching.

    DOI: 10.1242/bio.039164

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  16. tLyP-1-conjugated core-shell nanoparticles, Fe <inf>3</inf> O <inf>4</inf> NPs@mSiO <inf>2</inf> , for tumor-targeted drug delivery Reviewed

    Morita Y.

    Applied Surface Science   Vol. 474   page: 17-24   2019.4

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.apsusc.2018.09.205

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  17. Highly sensitive hydrogen sensor based on a new suspended structure of cross-stacked multiwall carbon nanotube sheet Reviewed International journal

    Yan, K., Toku, Y., Ju, Y.

    International Journal of Hydrogen Energy   Vol. 44 ( 12 ) page: 6344 - 6352   2019.3

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Elsevier {BV}  

    In this research, we proposed a highly sensitive hydrogen sensor based on a new suspended structure of cross-stacked multiwall carbon nanotube (MWCNT) sheet. MWCNT sheet is a kind of CNT film which has a super-high CNT alignment and can be easily prepared by drawing from the spinnable CNT array in large scales. By stacking the sheets onto an electrode with a 1 x 1 cm hole in mutually perpendicular directions, sensors with suspended cross-stacked structure were realized. Afterwards, a two-side Pd functionalization was introduced. The effects of suspended structure, cross-stacked structure and two-side Pd functionalization were investigated respectively. It was observed that the sample with 2 + 1 layers of cross-stacked MWCNT sheet and two-side 3 nm Pd deposition showed the best gas sensing performance with a relative resistance change of 35.30% at 4% H-2. This result indicates that the proposed sensor is one of the best among all reported MWCNT based hydrogen sensors. The method demonstrated in this research gives a potential solution for the mass production of CNT-based sensors with high sensitivity and reliability. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

    DOI: 10.1016/j.ijhydene.2019.01.055

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  18. Local permittivity measurement of dielectric materials based on the non-contact force curve of microwave atomic force microscopy. Reviewed

    Tong B, Zhao M, Toku Y, Morita Y, Ju Y

    The Review of scientific instruments   Vol. 90 ( 3 ) page: 033706   2019.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1063/1.5066599

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  19. A 64-pin Nanowire Surface Fastener Like a Ball Grid Array Applied for Room-temperature Electrical Bonding. Reviewed

    Toku Y, Ichioka K, Morita Y, Ju Y

    Scientific reports   Vol. 9 ( 1 ) page: 1095   2019.1

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1038/s41598-018-37693-2

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  20. Effect of electropulsing treatment on the fatigue crack growth behavior of copper Reviewed

    Yin Y.

    Materials   Vol. 11 ( 11 )   2018.11

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.3390/ma11112168

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  21. Fabrication of multiwall carbon nanotube sheet based hydrogen sensor on a stacking multi-layer structure Reviewed International journal

    Yan Keyi, Toku Yuhki, Morita Yasuyuki, Ju Yang

    NANOTECHNOLOGY   Vol. 29 ( 37 )   2018.9

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1351-6528/aace96

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  22. Nanowire surface fastener fabrication on flexible substrate Reviewed

    Toku Yuhki, Uchida Keita, Morita Yasuyuki, Ju Yang

    NANOTECHNOLOGY   Vol. 29 ( 30 )   2018.7

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1088/1361-6528/aac284

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  23. Synthesis of a single-crystal Fe2O3 nanowire array based on stress-induced atomic diffusion used for solar water splitting Reviewed

    Xie Yiyuan, Ju Yang, Toku Yuhki, Morita Yasuyuki

    ROYAL SOCIETY OPEN SCIENCE   Vol. 5 ( 3 )   2018.3

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1098/rsos.172126

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  24. Use of a tendon/ligament cell sheet with mesenchymal stem cells and cyclic stretch stimulus for tendon/ligament tissue restoration Reviewed

    Morita Y.

    Journal of Mechanical Engineering   Vol. 5 ( Specialissue3 ) page: 1 - 11   2018.2

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    Language:Japanese   Publishing type:Research paper (scientific journal)  

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  25. Optimization of differentiation time of mesenchymal-stem-cell to tenocyte under a cyclic stretching with a microgrooved culture membrane and selected measurement cells Reviewed International journal

    Yasuyuki Morita, Takahiro Yamashita, Yuhki Toku, Yang Ju

    ACTA OF BIOENGINEERING AND BIOMECHANICS   Vol. 20 ( 1 ) page: 3 - 10   2018

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:WROCLAW UNIV TECHNOLOGY, FAC COMPUTER SCIENCE & MANAGEMENT  

    Purpose: There is a need for efficient stem cell-to-tenocyte differentiation techniques for tendon tissue engineering. More than 1 week is required for tenogenic differentiation with chemical stimuli, including co-culturing. Research has begun to examine the utility of mechanical stimuli, which reduces the differentiation time to several days. However, the precise length of time required to differentiate human bone marrow-derived mesenchymal stem cells (hBMSCs) into tenocytes has not been clarified. Understanding the precise time required is important for future tissue engineering projects. Therefore, in this study, a method was developed to more precisely determine the length of time required to differentiate hBMSCs into tenocytes with cyclic stretching stimulus. Methods: First, it had to be determined how stretching stimulation affected the cells. Microgrooved culture membranes were used to suppress cell orientation behavior. Then, only cells oriented parallel to the microgrooves were selected and evaluated for protein synthesis levels for differentiation. Results: The results revealed that growing cells on the microgrooved membrane and selecting optimally-oriented cells for measurement improved the accuracy of the differentiation evaluation, and that hBMSCs differentiated into tenocytes in approximately 10 h. Conclusions: The differentiation time corresponded to the time required for cellular cytoskeleton reorganization and cellular morphology alterations. This suggests that cells, when subjected to mechanical stimulus, secrete mRNAs and proteins for both cy to skeleton reorganization and differentiation.

    DOI: 10.5277/ABB-00927-2017-04

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  26. ELECTROMAGNETIC PERFORMANCE OF SPIRALLY DEFORMED COATED NANOWIRES Reviewed

    Toku Yuhki, Ueda Yuji, Morita Yasuyuki, Ju Yang

    IRF2018: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON INTEGRITY-RELIABILITY-FAILURE     page: 347 - 348   2018

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  27. ELECTROMAGNETIC PERFORMANCE OF SPIRALLY DEFORMED COATED NANOWIRES Reviewed

    Yuhki Toku, Yuji Ueda, Yasuyuki Morita, Yang Ju

    IRF2018: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON INTEGRITY-RELIABILITY-FAILURE     page: 347 - 348   2018

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:INEGI-INST ENGENHARIA MECANICA E GESTAO INDUSTRIAL  

    In this study, we demonstrated the spiral formation of the metal coated nanowires (NWs). The spiral formation is a self-deformation technique based on the residual stress of the thin film. The NW works as a conductive coil at a nanoscale. The fabricated coil has a diameter of approximately 1-5 mu m and a high conductivity (similar to 2.18 x 10(6) /Omega.m). The conductive coil could be used for electromagnetic sensing according to the principle of electromagnetic induction. Specifically, it could be used for magnetic state observation and control at a nanoscale.

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  28. Evaluation of Local Dielectric Constant of Biomaterial Based on the Force-distance-curve Measured by Microwave Atomic-force Microscope Reviewed

    Minji Zhao, Bo Tong, Yuhki Toku, Yasuyuki Morita, Ju Yang

    2018 INTERNATIONAL SYMPOSIUM ON MICRO-NANOMECHATRONICS AND HUMAN SCIENCE (MHS)     page: 1 - 5   2018

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    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:IEEE  

    In recent years, different types of techniques have been developed to observe the cells and extract a wealth of information about their physiological properties. The analysis of the electrical properties requires modeling the cells. However, the cells have complex structures and most of the analytical equations are limited. Therefore, in this laboratory, the microwave detection system is combined with the atomic force microscopy (AFM) to evaluate the local electrical properties of the materials. In this research, a new method to measure the dielectric constant of biomaterials based on microwave was developed on microwave atomic force microscopy (M-AFM). The theoretical model was established to analyze the mechanism of the force caused by microwave and was developed a method to quantitatively measure the dielectric constant. By using this measurement method, the dielectric constant of mesenchymal stem cells (MSCs) was measured.

    DOI: 10.1109/MHS.2018.8886953

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    Other Link: https://dblp.uni-trier.de/db/conf/mhs/mhs2018.html#ZhaoTTMY18

  29. Enhancement of fatigue life of aluminum alloy affected by the density of pulsed electric current Reviewed

    Jung J., Ju Y., Morita Y., Toku Y.

    INTERNATIONAL JOURNAL OF FATIGUE   Vol. 103   page: 419-425   2017.10

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.ijfatigue.2017.06.021

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  30. Fabrication of Fe2O3 nanowire arrays based on oxidation-assisted stress-induced atomic-diffusion and their photovoltaic properties for solar water splitting Reviewed

    Xie Yiyuan, Ju Yang, Toku Yuhki, Morita Yasuyuki

    RSC ADVANCES   Vol. 7 ( 49 ) page: 30548-30553   2017

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    Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1039/c7ra03298f

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  31. Effect of pulsed electric current on the mechanical properties of titanium alloy Reviewed

    Jung J., Inadome Y., Ju Y., Morita Y., Toku Y.

    ICF 2017 - 14th International Conference on Fracture   Vol. 2   page: 798 - 799   2017

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    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:ICF 2017 - 14th International Conference on Fracture  

    The mechanical properties of titanium alloy affected by pulsed electric current were investigated. The elongation increased significantly after the application of electric current, while the yield and tensile strength were also increased. To examine the effect of electric current, the microstructures and fracture surfaces were compared before and after the application of electric current. It is concluded that the mechanical properties were improved due to the decrease of grain size and brittleness, and the occurrence of phase transformation.

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  32. Delaying Effect of High-Density Electric Current on Fatigue Crack Growth in A6061-T6 Aluminum Alloy Reviewed

    J. Jung, Y. Ju, Y. Morita, Y. Toku, and Y. Uematsu

    Materials Transactions     page: 000-000   2016

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  33. Effect of Pulsed Electric Current on the Growth Behavior of Fatigue Crack in Al Alloy Reviewed

    J. Jung, Y. Ju, Y. Morita, and Y. Toku

    Procedia Structural Integrity   Vol. 2   page: 2989-2993   2016

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  34. Electromagnetic Properties of Microcoils Fabricated from Self-Bending Coated-Nanowires via Viscous Flow of Core Material Reviewed

    Yuhki TOKU, Mikio MURAOKA

    Nanoscience and Nanotechnology Letters   Vol. 6 ( 7 ) page: 561-564   2014.7

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1166/nnl.2014.1776

  35. Repositioning Technique in Nanowire Manipulation by Oscillating Gripper" Reviewed

    Yuhki TOKU, Kohtaro KOBAYASHI, Mikio MURAOKA

    Micro and Nano Letters   Vol. 8 ( 2 ) page: 63-65   2013.2

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1049/mnl.2012.0665

  36. Helical Formation of Coated Nanowires by Viscous Flow of Core Material Reviewed

    Yuhki TOKU, Mikio MURAOKA

    Nanoscience and Nanotechnology Letters   Vol. 2 ( 3 ) page: 197-202   2010

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    Authorship:Lead author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1166/nnl.2010.1058

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MISC 23

  1. Fabrication of Nanowire Surface Fastener by Template Method Invited Reviewed

    TOKU Yuhki, JU Yang

    JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS   Vol. 66 ( 10 ) page: 756 - 761   2021.10

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    Language:Japanese   Publishing type:Article, review, commentary, editorial, etc. (scientific journal)   Publisher:Japanese Society of Tribologists  

    Surface-mount techniques primarily depend on soldering. However, soldering techniques have encountered some challenges in recent years. The reflow process in electronic assembly needs high-temperature processes, which result in undesired thermal damages and residual stress at a bonding interface. Therefore, there is an urgent requirement to attach electronic parts to circuit boards with good mechanical and electrical properties at room temperature. We recently developed a metallic nanowire surface fastener (NSF) to resolve the abovementioned problems. This fastener can connect electronic components on a substrate at room temperature using the van der Waals force between each nanowire. In this paper, we introduce a preparing method of a high-density nanowire array constituting the NSF. The NSF fabricated through the simple template method showed the room temperature bonding ability. The NSF’s adhesion strength and electrical properties were investigated by adjusting the nanowire parameters, such as diameter, length, density (number per area), preload, and shape. We also introduce some NSF applications, such as 64-pin NSF that behaves like a ball grid array for application to actual electronic devices and the fabrication of an NSF on a flexible substrate.

    DOI: 10.18914/tribologist.66.10_756

    CiNii Books

    CiNii Research

  2. Use of a tendon/ligament cell sheet with mesenchymal stem cells and cyclic stretch stimulus for tendon/ligament tissue restoration Reviewed

    Morita Y

    Journal of Mechanical Engineering   Vol. 5 ( Specialissue3 ) page: 1-11   2018.2

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    Language:English   Publishing type:Rapid communication, short report, research note, etc. (scientific journal)  

  3. Optimization of differentiation time of mesenchymal-stem-cell to tenocyte under a cyclic stretching with a microgrooved culture membrane and selected measurement cells Reviewed

    Yasuyuki Morita, Takahiro Yamashita, Yuhki Toku, Yang Ju

    Acta of Bioengineering and Biomechanics   Vol. 20 ( 1 ) page: 3 - 10   2018

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    Language:English   Publishing type:Rapid communication, short report, research note, etc. (scientific journal)   Publisher:Institute of Machine Design and Operation  

    Purpose: There is a need for efficient stem cell-to-tenocyte differentiation techniques for tendon tissue engineering. More than 1 week is required for tenogenic differentiation with chemical stimuli, including co-culturing. Research has begun to examine the utility of mechanical stimuli, which reduces the differentiation time to several days. However, the precise length of time required to differentiate human bone marrow-derived mesenchymal stem cells (hBMSCs) into tenocytes has not been clarified. Understanding the precise time required is important for future tissue engineering projects. Therefore, in this study, a method was developed to more precisely determine the length of time required to differentiate hBMSCs into tenocytes with cyclic stretching stimulus. Methods: First, it had to be determined how stretching stimulation affected the cells. Microgrooved culture membranes were used to suppress cell orientation behavior. Then, only cells oriented parallel to the microgrooves were selected and evaluated for protein synthesis levels for differentiation. Results: The results revealed that growing cells on the microgrooved membrane and selecting optimally-oriented cells for measurement improved the accuracy of the differentiation evaluation, and that hBMSCs differentiated into tenocytes in approximately 10 h. Conclusions: The differentiation time corresponded to the time required for cellular cytoskeleton reorganization and cellular morphology alterations. This suggests that cells, when subjected to mechanical stimulus, secrete mRNAs and proteins for both cytoskeleton reorganization and differentiation.

    DOI: 10.5277/ABB-00927-2017-04

    Scopus

  4. Improvement of adhesion strength of Au thin film by high-density electric current

    KIZAWA Kurama, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and processing conference   Vol. 2018.26 ( 0 ) page: 721   2018

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmemp.2018.26.721

    CiNii Research

  5. Local Permittivity Evaluation Based on the Force Variation of Microwave Atomic Force Microscopy

    Bo TONG, Minji ZHAO, Yuhki TOKU, Yasuyuki MORITA, Yang JU

    The Proceedings of The Computational Mechanics Conference   Vol. 2017.30 ( 0 ) page: 340   2017

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Microwave atomic force microscopy (M-AFM) is designed to realize the non-contact measurement of topography and electrical property at nanoscale simultaneously. For the evaluation of dielectric materials, since the detected reflected signal depends strongly on the probe-sample distance, in non-contact mode the quantitative evaluation regardless of the effect of distance is difficult. In this study, the effect of microwave on the force between the probe and dielectric materials was investigated. A theoretic model based on the reflection of electromagnetic wave was established to describe the distance dependence of microwave intensity between sample and probe. The relationship between the force gradient and sample permittivity was obtained and the permittivity of Al<sub>2</sub>O<sub>3</sub>, Ge, and ZrO<sub>2</sub> was evaluated using this theoretical model.

    DOI: 10.1299/jsmecmd.2017.30.340

    CiNii Research

  6. 312 Single-cell measurement on stem cell-to-tenocyte differentiation induced by cyclic stretch stimulation

    YAMASHITA Takahiro, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Conference of Tokai Branch   Vol. 2016 ( 0 ) page: _312 - 1_-_312-2_   2016

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmetokai.2016.65._312-1_

    CiNii Research

  7. Fabrication of Carbon-Nanotube Sheet based Hydrogen Sensor

    YAN Keyi, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and processing conference   Vol. 2016.24 ( 0 ) page: 406   2016

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Due to their high specific surface area and measurable change in conductance according to the chemical environment changes, carbon nanotubes (CNTs) have been proved to be an ideal material for next generation of gas sensor. However, before CNTs-based sensor can become a candidate for commercial implementation, there are still challenges including mass production of sensor arrays and improvement of sensor reproducibility. In this research, a high sensitivity CNT sheet-based gas sensor was fabricated, which can push forward the commercialization of CNT-based sensor. By controlling the reaction conditions during chemical vapor deposition (CVD) process, a spinnable CNT array was synthesized reproducibly. The CNT sheets were drawn from a sidewall of spinnable CNT array. CNT sheets were directly fixed onto Au electrodes and were heated up to 300°C for 2 h to oxidize amorphous carbon. Gas detection toward hydrogen gas was operated in a quartz tube chamber. With the change of gas concentration, the change in sensor resistances as response and recovery behavior was measured using a programmable electrometer. A sensitivity of 5% for 4% H<sub>2</sub> was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H<sub>2</sub> gas at room temperature was achieved by Pd functionalization.

    DOI: 10.1299/jsmemp.2016.24.406

    CiNii Research

  8. 722 Fabrication of Hook Nanowire Surface by Mechanical Bending

    TOKU Yuhki, KUSAMA Mika, JU Yang

    The Proceedings of the Materials and processing conference   Vol. 2015 ( 0 ) page: _722 - 1_-_722-3_   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmemp.2015.23._722-1_

    CiNii Research

  9. J2220204 Fabrication of Three Dimensional Nanostructures by Stress-induced Method

    WAKABAYASHI Nobuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan   Vol. 2015 ( 0 ) page: _J2220204 - -_J2220204-   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    In this study. we suggested simple and easy fabrication technique of flowe-like nanomaterials called Nano Flower (NF) by stress-induced method. From the observation of NFs grown on substrates which have different surface conditions, growth of NFs is probably related to residual stress of surface of substrates. EDS analysis results show that NFs grow up by taking in atmospheric carbon dioxide. NFs are expected as application to carbon dioxide capture and storage.

    DOI: 10.1299/jsmemecj.2015._J2220204-

    CiNii Research

  10. J0610105 Fabrication of Ultra-High Quality Al Nanowires Based on Stress-induced Method and Evaluation of Their Electrical Properties

    SHIBATA Takatoshi, TOKU Yuhki, JU Yang, KOJIMA Naoki

    The Proceedings of Mechanical Engineering Congress, Japan   Vol. 2015 ( 0 ) page: _J0610105 - -_J0610105-   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    We describe the result of the electrical conductivity measurement of single crystalline aluminum nanowires. These nanowires are fabricated by simply heating the Al samples in air. The growth mechanism is stress-induced migration. Four electrodes were patterned on nanowires by the photolithographic technique and we obtained the resistivity of nanowires by four-terminal measurement. The relationship between electrical conductivity and diameter was examined experimentally.

    DOI: 10.1299/jsmemecj.2015._J0610105-

    CiNii Research

  11. J0610104 Evaluation of Interatomic Force on the Tip of Probe by using Microwave Atomic Force Microscope

    HIFUMI Kazuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan   Vol. 2015 ( 0 ) page: _J0610104 - -_J0610104-   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures such as nanowires. To apply these nanomaterials and nanostructures into nanodevices, there are great needs of the quantitative measurement of electrical properties of materials in an infinitesimal area. Recently, it has been reported that the microwave gives an effect to an interatomic force in local area among materials. Therefore, it is thought that an identification of materials and an evaluation of electrical characteristics become possible by clarifying the relation between microwave and interatomic force. Therefore, we investigated interatomic force under the tip of probe by focusing on the force-distance curve measurement using microwave atomic force microscopy (M-AFM) as the first step. This paper describes the method and the results of the force-distance curve measurement on the sample of Au, Si, and glass. Results of this experiment indicate actually that the effect of microwave is large in material which has high electric conductivity.

    DOI: 10.1299/jsmemecj.2015._J0610104-

    CiNii Research

  12. GS0706-432 The Fabrication of High Density Single Crystal Al Nanowires by Stress Migration

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference   Vol. 2015 ( 0 ) page: _GS0706 - 43-_GS0706-43   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Nanowires have been expected to be utilized in various applications. Recently, many researchers have reported about single crystal or polycrystalline nanowires where the single crystal nanowires are shown to have a higher conductivity compared to the polycrystalline ones. In our previous study, we investigated the fabrication process of single crystal nanowires by stress migration. However, because the mechanism of fabrication was not clear, the generation density of single crystal nanowires was low for this method. In this study, we suggested a new method to increase the generation density of single crystal nanowires. An etching process was added to the previous fabrication method and the conditions of the substrate surface were changed. By doing this, the stress generated around the concentrated Al atoms was larger than the threshold stress needed to fabricate the nanowires. As a result of the added etching process, we achieved a nanowire generation density 100 times that of the conventional fabrication method.

    DOI: 10.1299/jsmemm.2015._GS0706-43

    CiNii Research

  13. GS0705-431 Fabrication and Evaluation of Cu_2O Solar Cell with Core-Shell Nanowires

    MATSUO Ryosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference   Vol. 2015 ( 0 ) page: _GS0705 - 43-_GS0705-43   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Currently, the solar cells are mainly made of silicon. However, due to the high cost and shortage of silicon, new materials for solar cells are still needed. It has been proved that Cu_2O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu_2O solar cell is much lower than theoretical one. In this research, Cu_2O/Cu core-shell nanowires are fabricated on the surface of the solar cell by the template method to increase light receiving area. Then, elemental analysis for core-shell nanowires is carried out by Electron Energy-Loss Spectroscopy. As a result, we succeed in fabricating Cu_2O/Cu core-shell nanowires. The area of the solar cells is increased to about 220 times, which is convinced to improve the solar energy conversion efficiency.

    DOI: 10.1299/jsmemm.2015._GS0705-43

    CiNii Research

  14. F041003 Development of Functional Nanowire Surface Fastener

    JU Yang, TOKU Yuhki

    The Proceedings of Mechanical Engineering Congress, Japan   Vol. 2015 ( 0 ) page: _F041003 - 1-_F041003-3   2015

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we introduce a new patterned structure of nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized. The mechanical bonding enables normal and shear bonding strengths of more than 5 N/cm^2. Simultaneously, the parasitic resistance of a pair of surface fasteners is only approximately 2Ω. The present technique can be performed at room temperature, thereby improving the process compatibility and reliability of SMDs. Surface fasteners based on high melting point metallic nanowires are temperature-resistant for many critical applications. In addition, bonding without solder material is positive for the recycling of rare metals in SMDs.

    DOI: 10.1299/jsmemecj.2015._F041003-1

    CiNii Research

  15. OS1507 Investigating Effect of Film Thickness on Bending Deformation of Metal-Coated Nanowires

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and Mechanics Conference   Vol. 2014 ( 0 ) page: _OS1507 - 1_-_OS1507-2_   2014

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    In this study, we discussed about the effect of film thickness on bending deformation of coated nanowire (NW). The three dimensional theoretical model for analyzing the effect was proposed in this paper. The dependence of the misfit strain on the film thickness was introduced in the model. We concluded that bending direction of the NW varied with increasing the coating film thickness. This result arises from the dependence of the misfit strain on the film thickness and the nonuniform film thickness along the circumference of the NW.

    DOI: 10.1299/jsmemm.2014._OS1507-1_

    CiNii Research

  16. 211 Theoretical Analysis for Helical Formation of Coated Nanowire by Viscous Flow of Core Material

    KUDO Ryusuke, TOKU Yuhki, MURAOKA Mikio

    The Proceedings of Autumn Conference of Tohoku Branch   Vol. 2013 ( 0 ) page: 51 - 52   2013

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmetohoku.2013.49.51

    CiNii Research

  17. J212014 Evaluation for Magnetic Field of Metal-Coated Microcoils Formed by Viscous Flow of Core Material

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of Mechanical Engineering Congress, Japan   Vol. 2013 ( 0 ) page: _J212014 - 1-_J212014-2   2013

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    We have proposed a method on helical formation of coated nanowire, which utilized the misfit strain of the film coated on the nanowire. We also adopted a heat treatment that induces a creep flow only in the nanowire and thereby released the constraint of the nanowire on elastic bending due to film strain. In this study, we evaluate the magnetic field of Pt-coated CuO microcoils formed by using the method. A direct current is supplied to the coil on Au electrodes, and the voltage of the coil is measured using four-point probe method. The coil is melted due to a possible reason of joule heating at a current of 700 μA. The measured voltage increases proportionally to the increasing current until the current is 580 μA. Then, the voltage irregularly increases until the electrical discontinuity. We predict that the density of magnetic flux of the coil is 1.2 G at the current of 580 μA. This magnetic field is 3〜4 times of the geomagnetism.

    DOI: 10.1299/jsmemecj.2013._J212014-1

    CiNii Research

  18. 511 Observation of Topological Change of Metal-Coated Nanowire under Current Supply

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and processing conference   Vol. 2013 ( 0 ) page: _511 - 1_-_511-2_   2013

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmemp.2013.21._511-1_

    CiNii Research

  19. 330 Helical Formation of Metal-Coated Nanowires by Core Reduction to Release Residual Stress

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and processing conference   Vol. 2012 ( 0 ) page: _330 - 1_-_330-2_   2012

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmemp.2012.20._330-1_

    CiNii Research

  20. OS06-2-4 Manipulation of Nanowires by Chopsticks

    Kobayashi Kohtaro, Toku Yuhki, Muraoka Mikio

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics   Vol. 2011 ( 10 ) page: "OS06 - 2-4-1"   2011.9

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    Language:English   Publisher:The Japan Society of Mechanical Engineers  

    CiNii Books

  21. 002 Bend Processing of Metal-Coated Nanowires by Viscous Flow of Core Material and Intrinsic Strain of Coating Film

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and Mechanics Conference   Vol. 2010 ( 0 ) page: 258 - 259   2010

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Various methods have been proposed for fabricating nanocoils in order to extend the range of elements for building nanodevices. Most of these methods are based on self-assembly technique. We have previously demonstrated an alternative method in which a straight nanowire is bent by depositing a thin film on the nanowire. The bending is due to the misfit strain of the coated film. However, nanocoil formation using this method is highly inefficient. In this study, we developed an advanced method in which the helical formation of coated nanowires takes place because of the viscous flow of the core material, i.e., the nanowires, and the misfit strain of the coating film. When the melting temperature of the nanowire material is lower than that of the coating, elevating the temperature induces a viscous flow, i.e., creep, which only occurs in the nanowire. The creep releases the constraint of the nanowire on elastic bending due to film strain.

    DOI: 10.1299/jsmemm.2010.258

    CiNii Research

  22. T0301-1-4 Curvature Control of Nanocoils Produced by Viscous Flow of Core Material

    TOKU Yuhki, MURAOKA Mikio

    The proceedings of the JSME annual meeting   Vol. 2010 ( 0 ) page: 173 - 174   2010

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    Various methods have been proposed for fabricating nanocoils in order to extend the range of elements for building nanodevices. Most of these methods are based on self-assembly technique. We have previously demonstrated an alternative method in which a straight nanowire is bent by depositing a thin film on the nanowire. The bending is due to the misfit strain of the coated film. However, nanocoil formation using this method is highly inefficient. In this study, we developed an advanced method in which the helical formation of coated nanowires takes place because of the viscous flow of the core material, i.e., the nanowires, and the misfit strain of the coating film. When the melting temperature of the nanowire material is lower than that of the coating, elevating the temperature induces a viscous flow, i.e., creep, which only occurs in the nanowire. The creep releases the constraint of the nanowire on elastic bending due to film strain.

    DOI: 10.1299/jsmemecjo.2010.8.0_173

    CiNii Research

  23. 104 Herical Formation of Metal-Coated Nanowires by Viscous Flow of the Core Material

    TOKU Yuki, MURAOKA Mikio

    The Proceedings of Conference of Tohoku Branch   Vol. 2010 ( 0 ) page: 12 - 13   2010

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    Language:Japanese   Publisher:The Japan Society of Mechanical Engineers  

    DOI: 10.1299/jsmeth.2010.45.12

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Presentations 304

  1. Improvement of Thin Film Adhesion Strength via Current Application International conference

    Y. Toku, K. Kizawa, K. Sugiura, Y. Morita and Y. Ju

    Asia-Pacific Conference on Fracture and Strength 2018 

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    Event date: 2018.10

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Xi'an, China   Country:China  

  2. ELECTROMAGNETIC PERFORMANCE OF SPIRALLY DEFORMED COATED NANOWIRES International conference

    Y. Toku, Y. Ueda, Y. Morita and Y. Ju

    Recent Developments in Integrity - Reliability - Failure 

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    Event date: 2018.7

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Lisbon, Portugal   Country:Portugal  

  3. Influence of Thermal Fatigue on the Connection Strength of Nanowire Surface Fastener International conference

    Y. Toku, S. Nota, Y. Morita, and Y. Ju

    International multi-conference on engineering and technology innovation 2015 

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    Event date: 2016.8

    Language:English   Presentation type:Oral presentation (general)  

    Venue:New York, USA   Country:United States  

  4. Fabrication of tiny whiskers on core-shell nanowires based on stress-induced atomic migration International conference

    Yuhki TOKU, Mikio MURAOKA, Yang JU

    International multi-conference on engineering and technology innovation 2015 

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    Event date: 2015.10 - 2015.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:Kaohsiung, Taiwan   Country:Taiwan, Province of China  

  5. A System for the Fabrication of Metallic Micro/Nanowire Based on Electromigration International conference

    ITO Yuta, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    33rd International Microprocesses and Nanotechnology Conference (MNC2020)  2020.11.9 

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    Event date: 2020.11

    Language:English   Presentation type:Oral presentation (general)  

  6. 高周波高密度電流が銅薄膜の密着強度に及ぼす影響

    安田 和弘, 木村 康裕, 徳 悠葵, 巨 陽

    年次大会 

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    Event date: 2020.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Stainless alloy is widely used in implants, dams and bridges because of its high corrosion resistance. However, these structures can be exposed to loads during their useful life and cause plastic deformation. Therefore, it is essential to know the plastic strain of the material in order to control the quality of the product. The conventional way to measure strain is the strain gauge method, but since physical contact is required at the time of gage attachment, a method to measure strain in non-contact fashion is required. Therefore, in this research, we focused on microwaves often used in nondestructive testing. Microwaves have less influence on the human body compared to X-ray. Unlike ultrasonic waves, microwaves do not require a transmission medium and can propagate in air favorably and at high speed. Therefore, we used microwaves to measure the electrical resistivity of plastically deformed test pieces. As a result, correlations were confirmed between the measured electrical resistivity and strain, and it was shown that the strain of stainless steel could be evaluated from the measured electrical resistivity.</p>

    DOI: 10.1299/jsmemecj.2019.J40136P

  7. エレクトロマイグレーションによる金属マイクロ・ナノワイ ヤ創製のための機構開発

    伊藤 佑太, 木村 康裕, 徳 悠葵, 巨 陽

    年次大会 

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    Event date: 2020.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Stainless alloy is widely used in implants, dams and bridges because of its high corrosion resistance. However, these structures can be exposed to loads during their useful life and cause plastic deformation. Therefore, it is essential to know the plastic strain of the material in order to control the quality of the product. The conventional way to measure strain is the strain gauge method, but since physical contact is required at the time of gage attachment, a method to measure strain in non-contact fashion is required. Therefore, in this research, we focused on microwaves often used in nondestructive testing. Microwaves have less influence on the human body compared to X-ray. Unlike ultrasonic waves, microwaves do not require a transmission medium and can propagate in air favorably and at high speed. Therefore, we used microwaves to measure the electrical resistivity of plastically deformed test pieces. As a result, correlations were confirmed between the measured electrical resistivity and strain, and it was shown that the strain of stainless steel could be evaluated from the measured electrical resistivity.</p>

    DOI: 10.1299/jsmemecj.2019.J40136P

  8. Adhesion Properties of Nanowire Surface Fastener Invited

    Toku Y.

    MHS 2019 - 30th 2019 International Symposium on Micro-NanoMechatronics and Human Science 

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    Event date: 2019.12

    Language:Japanese   Presentation type:Oral presentation (keynote)  

    DOI: 10.1109/MHS48134.2019.9249283

    Scopus

  9. The effect of cancer assisted fibroblasts on mechanical field of cancer invasion

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2019.31.2F22

  10. DVC Measurement on the Deformation Field of ECM Surrounding a Tumor Spheroid During the Invasive Progression International conference

    Morita Yasuyuki, Nakano Yusuke, Oshima Kanau, Toku Yuhki, Ju Yang

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 

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    Event date: 2019

    Language:English   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmeatem.2019.1009D1000

  11. 機械的伸縮刺激を用いた間葉系幹細胞の腱細胞分化誘導に対する伸縮波形の影響

    丹羽 光司, 森田 康之, 徳 悠葵, 巨 陽

    生体医工学 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>幹細胞に伸縮刺激を与えると機能亢進が起こる. そのメカニズムは明らかにされていないが, 近年の研究で伸縮周波数が大きな影響を持つことが示唆されている. 本研究では腱細胞への分化に焦点をあて,遺伝子発現量を観察することで, 間葉系幹細胞の腱分化特性を評価する. 初めに,伸縮刺激を各細胞に一様に加えることを目的に細胞培養膜を作製し, 細胞の配向を制御した. その後, 周波数を0.1~10Hzと広域に設定し, 伸縮実験を行った.その結果,腱組織の生理環境に近い0.1および1Hzの領域で大きな遺伝子発現が見られた.</p>

    DOI: 10.11239/jsmbe.Annual57.S25_1

  12. Experimental study on influence of ECM elasticity on invasive behavior of tumor cells

    USHIDA Masato, MORITA Yasuyuki, OSHIMA Kanau, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Cancer cells are known to lead human death, but they are difficult to treat. The reason is that the mechanism of metastasis has not been elucidated. Since cancer cells are known to induce the hardening and moving surrounding tissues i.e. extracellular matrix (ECM), this study aimed to increase the elastic modulus of ECM without changing the density of collagen fibers. The crosslinking agent (EDCNHS) was used for this purpose. By making collagen gel with administering the crosslinking agent, it was succeeded to increase the elastic modulus of ECM up to 5 times approximately than the case without crosslinking agent. Based on this result, it is possible to observe the infiltration behavior of cancer cells with the difference of elastic modulus under three-dimensional culture by enclosing cancer cells in the collagen gel.</p>

    DOI: 10.1299/jsmemecj.2019.J02303

  13. Non-contactive measurement of strain in stainless steel by microwaves

    ITO Atsushi, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Stainless alloy is widely used in implants, dams and bridges because of its high corrosion resistance. However, these structures can be exposed to loads during their useful life and cause plastic deformation. Therefore, it is essential to know the plastic strain of the material in order to control the quality of the product. The conventional way to measure strain is the strain gauge method, but since physical contact is required at the time of gage attachment, a method to measure strain in non-contact fashion is required. Therefore, in this research, we focused on microwaves often used in nondestructive testing. Microwaves have less influence on the human body compared to X-ray. Unlike ultrasonic waves, microwaves do not require a transmission medium and can propagate in air favorably and at high speed. Therefore, we used microwaves to measure the electrical resistivity of plastically deformed test pieces. As a result, correlations were confirmed between the measured electrical resistivity and strain, and it was shown that the strain of stainless steel could be evaluated from the measured electrical resistivity.</p>

    DOI: 10.1299/jsmemecj.2019.J40136P

  14. Mechanical Effects of CAFs on the Invasion Field of a Cancer Cell via Extracellular

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2019.32.1F14

  15. Improvement of Mechanical Properties of Titanium alloy by High-Density Pulsed Electric Current

    IWASE Rui, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Titanium alloys have been widely used in versatile productions due to their excellent mechanical properties. Conversely, the effective technique for the improvement of mechanical properties is required. Although heat treatment is used to enhance the mechanical properties, it increases processing cost. Recently, high-density pulsed electric current (HDPEC) has been studied for repairing defects and damages in metallic materials. Therefore, it would be expected to improve mechanical properties of Titanium alloy by applying HDPEC instead of heat treatment. This work studied the effect of HDPEC on the mechanical properties of Titanium alloy Ti-6Al-4V. Tensile test was conducted after applying HDPEC to the material. The application of HDPEC contributes to improve the elongation and tensile strength of 10% and 3.2% compared to unapplied ones, respectively. In addition, Vickers hardness was decreased with increasing current density. The change in the microstructure of the material before and after applying HDPEC was observed based on the X-ray diffraction analysis: The rate of <i>β</i>-phase in the material was increased by applying HDPEC. As a result, the mechanical properties of titanium alloy were improved by applying HDPEC due to the phase transformation.</p>

    DOI: 10.1299/jsmemm.2019.OS0326

  16. Increase in Adhesion Strength of Au Thin Film via High-frequency and High-density Electric Current

    KIZAWA Kurama, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In recent years, electronic devices have remarkably achieved miniaturization and high performance with the development of MEMS. In addition, the current density in the interconnect has risen due to the increase of electric energy accompanying the development of power devices. The delamination of thin film due to thermal stress and electromigration has become a problem. One method to improve the adhesion strength of thin film on a substrate is using an adhesion layer such as Cr or Ti between the thin film and the substrate. However, this method has the disadvantages that additional materials are required and the thickness of the interconnect increases. The adhesion strength of the thin film needs to be improved itself. This study proposed a method to apply high-density current with high frequency to thin film to improve the adhesion strength of it. The Au thin film (Size: 5 mm×45 mm×150 nm) was deposited on a glass substrate by radio frequency sputtering. Then, high-density current with high frequency was applied in thin film and the adhesion strength was measured by using peel test. As a result, the adhesion strength was improved by 20% or greater by applying high-density current with high frequency. Therefore, this method is expected to be a new strength improvement method for thin film.</p>

    DOI: 10.1299/jsmemm.2019.OS1409

  17. Development of functional DDS carrier utilizing temperature-responsive polymer

    KOBAYASHI Kodai, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2019.32.2D23

  18. Development of Controlled-Release DDS Carrier Applicated Temperature-Responsive Polymer

    KOBAYASHI Kodai, MORITA Yasuyuki, WAKIMOTO Takuma, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Drug delivery system (DDS) is able to realize the treatment of cancer with lower side effects and higher efficiency comparing to conventional chemotherapy by controlling the in vivo dynamics of drugs. In recent years, there are many studies regarding to the release control of anticancer drug loaded in DDS in order to enhancing its performance. However, so far the reported controllable drug release DDSs require external stimulation such as light and cooling as triggers for drug release, which cannot reach the deep part inside the human body. To control the release in the deep part inside the human body, here, we aimed at to develop a new DDS carrier which can control drug release by applying magnetic field. Magnetic mesoporous silica (MMS) and ureido-containing poly (allylamine-co-allylurea) copolymers (PAU) were used in this study. PAU is a kind of polymer having upper critical temperature. By modifying it to the surface of magnetic mesoporous silica, it is possible to realize the control of drug release of the DDS carrier triggered by the core heat generation induced by an alternating magnetic field, thereby realizing the control of drug release in the deep part inside the human body. DDS carrier developed in this research enables highly efficient treatment that combines hyperthermia with core heat generation and drug treatment with drug release at the cancer in the body. To synthesize PAU modified MMS (MMS-PAU), magnetite was prepared by thermal decomposition method and MMSs were synthesized by a template method. PAU was prepared by reacting polyallylamine with potassium cyanate. Finally, PAU was grafted on the surface of MMS by introducing amide bonds. We confirmed that MMS-PAU has the drug release control ability and MMS-PAU is effective for cancer therapy.</p>

    DOI: 10.1299/jsmemm.2019.GS25

  19. Development of Flexible Transparent Conductive Film with Carbon Nanotube Sheet

    TAGUCHI Takuto, KIMURA Yasuhiro, TOKU Yuhki, JU Yan

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In Recent years, the demand of transparent conductive films (TCFs) has been increased widely due to the potential application for electronic devices, such as touch panels, liquid crystal displays, and transparent electrodes. With the development of flexible devices, TCFs are required to be flexible. However, indium tin oxide (ITO), the most widespread material used for TCFs, is brittle ceramic material and expensive. Therefore, instead of ITO, TCF materials have to be flexible and low cost. Multiwalled carbon nanotubes (CNT) sheet has been studied as a replacement for ITO owing to its flexibility and low cost. However, the sheet resistance of CNT sheet is still higher than that of ITO: the values of 1000to 1500 Ω/□. One of the reasons is the contact resistance of each other of CNTs in a CNT sheet. In this study, metal nanoparticles were coated on the CNT sheet to reduce the contact resistance. After being coated with Cu/Ni, the contact resistance was modified and the sheet resistance was reduced to 300 Ω/□ or less, while the transmittance at the wave length of 550 nm maintains 80 % or higher. The results provide that CNT sheet is a promising candidate for flexible TCF material, realizing more effective production at lower cost than ITO.</p>

    DOI: 10.1299/jsmemm.2019.GS24

  20. Enhancement of Solar-to-hydrogen Conversion Efficiency in Water Splitting by Optimizing Morphology of Cu<sub>2</sub>O Nanostructure and Surface Modification

    IZUMI Yuri, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Recently, Cu<sub>2</sub>O has been considered as an attractive material for solar water splitting due to its excellent characteristics such as small bandgap, visible light adsorption, abundance, and nontoxicity. The theoretical solar-to-hydrogen conversion efficiency (STH) of Cu<sub>2</sub>O is 18% for water splitting. To date, the value experimentally obtained by previous works has not attained and overcomed above ideal value, because of the lack of Cu<sub>2</sub>O in photocathode to absorb sunlight efficiently, the short diffusion length of minority cariers, and the Cu<sub>2</sub>O photocorrosion during water splitting. 3D nanostructures for water splitting and surface modification contribute to resolving these issues. Nanostructures can improve STH owing to high surface-to-volume ratio and short diffusion length for carrier transport compared with bulk materials. In addition, surface modification enables to promote the separation of photogenerated electron-hole pair and to protect the photoelectrode against photocorrosion, and thus resulting in the enhancement of stability in Cu<sub>2</sub>O photocathode. The present study aimed to improve STH and stability in Cu<sub>2</sub>O photocathode for water splitting by optimizing morphology of Cu<sub>2</sub>O nanostructures and surface modification. In order to determine the suitable conditions for water splitting, the relationship between the morphology of the structure and STH was examined. The photocathode with Cu<sub>2</sub>O nanostructures exhibited maximum photocurrent density of 4.58 mA/cm<sup>2</sup> at a potential of 0 V vs. reversible hydrogen electrode (RHE) and STH of 5.63%. Besides, surface modification was successfully introduced by covering nanostructures with homogeneous and conformal layers formed by atomic layer deposition (ALD).</p>

    DOI: 10.1299/jsmemm.2019.GS11

  21. Three-Dimensional Measurement of the Mechanical Fields and Fiber Structure around Cancer Cells Co-Cultured with CAFs

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2019

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Invasion of cells plays a major role in metastasis. Cancer cells interact with cancer-associated fibroblasts (CAFs) present in the tumor microenvironment and as a result enhance their invasive ability. However, the overall mechanism of the interaction has not been clarified. When cancer cells moving, they constantly exert power on the surrounding extracellular matrix (ECM). In addition, the material properties of the ECM are not uniform because the fiber structure constantly changes. Therefore, measuring the mechanical field around cancer cells is significant in revealing the interaction between cancer cells and CAFs. In this study, we analyze what kind of change is caused in the mechanical field of ECM around a cancer cell by the effects of CAFs under three dimensional culture. We cultured the pancreatic ductal carcinoma cells, SUIT-2 with the orthotopic CAFs in collagen gel. Three-dimensional images were acquired by a confocal microscope. Embedding the fluorescent beads in the gel at the same time, the beads adhere to the collagen and form a pattern, therefore it is possible to track the displacement field by using the digital volume correlation (DVC) method. At the same time, the collagen fiber density and orientation were evaluated based on 3D images. As a result, accumulation and arrangement of collagen fibers were observed in the direction of CAF protrusion, and it became clear that cancer cells under the influence of CAFs generate a dynamic field in a wider range.</p>

    DOI: 10.1299/jsmemm.2019.OS0509

  22. Evaluation of Local Dielectric Constant of Biomaterial Based on the Force-distance-curve Measured by Microwave Atomic-force Microscope

    Zhao M.

    MHS 2018 - 2018 29th International Symposium on Micro-NanoMechatronics and Human Science 

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    Event date: 2018.12

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1109/MHS.2018.8886953

    Scopus

  23. Controlled drug release of Fe3O4@mSiO2 nanoparticles with phase transition behavior of thermosensitive polymer

    WAKIMOTO Takuma, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2018  The Japan Society of Mechanical Engineers

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2018.30.1H16

  24. Influence of ECM elasticity to dynamics field of ECM during stem cells differentiation

    YAMAMOTO Ryosuke, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2018  The Japan Society of Mechanical Engineers

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2018.30.1A18

  25. Development of Cu2O 3D nanostructure used for photo electrode of solar water splitting

    IZUMI Yuri, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemecj.2018.J2220104

  26. Improvement of mechanical properties of stainless steel alloy based on the electroplastic effect

    IWASE Rui, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemecj.2018.J0450402

  27. Measurement on mechanical dynamic field of ECM induced by the process of stem-cell differentiation with different ECM elasticities

    MORITA Yasuyuki, YAMAMOTO Ryosuke, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemecj.2018.J0270101

  28. Application of a temperature-responsive polymer to a core-shell nanocarrier for development of controlled-release DDS

    KOBAYASHI Kodai, MORITA Yasuyuki, WAKIMOTO Takuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemecj.2018.J0220304

  29. Improving spinnability of carbon nanotube sheet by controlling the density and alignment of carbon nanotube array

    TAGUCHI Takuto, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemecj.2018.J2220103

  30. Stress measurement of tumor-cell spheroid using oil-droplet mechanical sensor

    UMEI Wataru, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebiofro.2018.29.1B16

  31. Improvement of adhesion strength of Au thin film by high-density electric current

    KIZAWA Kurama, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and processing conference  2018  The Japan Society of Mechanical Engineers

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemp.2018.26.721

    CiNii Research

  32. Control of Shape and Density of SnO<sub>2</sub> Nanobelt

    TOGAWA Yosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In recent years, various nanostructure materials such as nanowires, nanorods and nanobelts have been studied widely due to their excellent properties. Especially, much attention was paid by researchers in the preparation of oxide nanostructure materials due to their good optical and electrical properties. Numerous oxide nanostructure materials were synthesized so far, among which SnO<sub>2</sub> is considered to be an important one, because it is a typical n-type semiconductor. Particularly, SnO<sub>2</sub> nanobelts exhibited extensive optoelectronic and gas-sensitive properties which make them being excellent candidates for a wide range of applications such as gas sensors and transparent conductive film. SnO<sub>2</sub> nanobelt is generally synthesized by thermal evaporation method, but it is difficult to control the shape, size and density of SnO<sub>2</sub> nanobelts in the thermal evaporation process. However, since the elastic modulus and conductivity of the nanobelt depend on its shape and size, it is important to control shape and size of nanobelt. Hence, in this study, we adjusted experimental parameters such as pressure during heating and concentrations of gold nanoparticle solution to control the shape and size of nanobelts. From the scanning electron microscope image, we found that the aspect ratio of cross-section was controlled by pressure during heating. The results show that we succeeded in controlling the aspect ratio of cross-section and density of the SnO<sub>2</sub> nanobelts. From the above, it is expected that the improvement of flexibility and transparency of a transparent conductive film could be realized.</p>

    DOI: 10.1299/jsmemm.2018.GS0205

  33. Experimental study on the stress state of 3D ECM at the start of invasion of cancer spheroids

    NAKANO Yusuke, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>When tumor cells metastasize, invasion of cells plays a major role. The tumor cells initiate invasion by generating force and changing the physical structure of the extracellular matrix (ECM) surrounding the tumor. However, the detail process of changing the structure of the ECM has not been elucidated. At this time, measuring the mechanics field generated in the ECM is an important way to understand behavior of tumor cells in 3D. Therefore, in this study, spheroids, which are the source of the invasion as a tumor cells, were embedded in a collagen gel, and the deformations of the collagen gel surrounding the spheroids were measured. Using the DVC method, the matrix deformations around spheroids were measured by tracking the 3D positions of fluorescent beads embedded in the collagen gel. To photograph the initial state of the ECM, we added tritonX-100 to the spheroid at the end of the experiment and photographed the state of no stress from the spheroid. In addition, we calculated the divergence of the deformations field and discussed on density change of ECM. As a result, it was found that spheroids systematically generate the deformation field and change the density of ECM. It was suggested that invasion occurs in the low density part.</p>

    DOI: 10.1299/jsmemm.2018.OS0610

  34. Fabrication of Cu<sub>2</sub>O Nanowire Array by Thermal Oxidation and Reduction Process used for Solar Water Splitting

    ZHANG Yiqi, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>It is well-known that traditional fossil energy sources such as oil are limited. Hydrogen is attracting the attention of the world because it is renewable, plentiful in supply, clean and non-toxic. Cu<sub>2</sub>O is a promising material for solar water splitting because it has an impressive performance as photocathode. It is a p-type semiconductor and with a band gap of 2.0 eV, which could theoretically deliver a solar to hydrogen conversion efficiency of 18% for water splitting. In this research, we use tube furnace to fabricate Cu<sub>2</sub>O nanowire (NW) by thermal oxidation and reduction process of thin copper plate. Different experimental conditions (temperature, time and gas flow rate) were investigated to find out the best parameters for nanowire synthesis (diameter, length, and number density of NW) which is better for the photoelectrochemical system.</p>

    DOI: 10.1299/jsmemm.2018.GS0302

  35. Fabrication of Single Crystal Al Nanowire Array by Stress-induced Atomic Diffusion for Development of Transparent Conductive Film

    TANAKA Yuki, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In recent years, the development of a transparent conductive film using metal nanowires (NW) as a dispersing material has been carried out. Recent studies have reported many methods for fabricating transparent conductive films using Ag NW. However, Ag is a rare metal and there is a problem that the price is susceptible to market fluctuations. In order to utilize inexpensive Al NW as a new dispersing material, we developed a single crystal Al NW array fabrication method. The present method utilizes atomic diffusion to convert Al atoms to NW shape. Compressive stress and stress gradient in the Al thin film which is generated due to the difference in linear expansion coefficient between Al and Si when heating the Al / Si substrate. The atomic diffusion phenomenon caused by such stress is called stress migration (SM). It is a major feature of this method that NW generation is possible with two simple steps, film formation and heating. However, this method has a problem that the generation density of Al NW is low. In this research, we tried to increase the stress gradient by partial etching of Al film and introduce adhesion intermediate layer, and tried to improve generation density. As a result, we could get high density of Al NW with etching depth 10 nm and Cr film thickness 1.5 nm.</p>

    DOI: 10.1299/jsmemm.2018.GS0301

  36. Development of ZnO Thin Film Sensor Array for Minute Pressure Measurement

    KAWAI Kota, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Cancer is one of the three major causes of death in Japan. The 90% of patients with cancer dies from metastasis. Therefore, it is essential to do the cancer treatment properly, in which the metastasis should be prevented or the place should be predicted where the cancer cells are going to spread to. However, the mechanical mechanism of metastasis is still under research. We attempt to develop a pressure sensor array that can continuously measure the force of nN order generated by the cancer cells in a distributed manner. The requirements that a pressure sensor array need to meet are as follows: the pressure sensor array must adhere to the surface of a cancer cell via many points, besides, it could measure the magnitude of the force (nN). The zinc oxide (ZnO) thin film, as the piezoelectric material, offers a desirable approach to fulfilling the need for measurement of the mechanical field generated by the cancer cells. In our research, we fabricated a set of plural sensors (Size: 100 μm×100 μm, Thickness: 1 μm) on a substrate by using the methods of sputtering and photolithography. In other words, we developed a multi-point pressure sensor array. The main purpose of this study is to evaluate the sensitivity of the sensor, we used Au or Cr buffer layers, on which the ZnO thin film was formed, to find out the influence of the sensitivity of the sensor. Moreover, we measured the output voltage as a function of the load by using the sensor. In summary, the result of experiments shows that the sensitivity of the sensor is 5.31 mV/N.</p>

    DOI: 10.1299/jsmemm.2018.GS0204

  37. Optimization of Effective Parameters for Improving Adhesion Strength of Copper Nanowire Surface Fastener

    KATO Motohiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2018

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In recent years, connecting techniques using conductive nanomaterials imitating gecko's feet, for example, metal nanowires, carbon nanotubes and conductive polymer materials as a surface fastener have been reported. These connecting techniques utilize van der Waals force generated between the surfaces of nanomaterials. Recently, we have developed the copper nanowire surface fasteners (Cu NSF) as a conductive connector. Since copper has high electrical conductivity and is inexpensive, the Cu NSF can be expected to be practically used as a new surface mounting technique. Moreover, Cu NSF can be connected at room temperature utilizing van der Waals force, so that it is possible to avoid the damage to electronic parts during solder reflow process. However, the adhesion strength of current Cu NSF is still small as compared with traditional solders. The reason is considered that the contact areas of the nanowires were not sufficient because the nanowires collided and collapsed during connecting. In this research, we attempted to increase the contact area of nanowires for improving adhesion strength of Cu NSF. The adhesion strength of the Cu NSFs having nanowires with 100 nm and 400 nm diameter reached the largest value, and increasing with the increase of preload. This investigation showed that the contact areas of nanowires increased and mechanical entanglement of nanowires occurred because of increasing the preload of connecting.</p>

    DOI: 10.1299/jsmemm.2018.OS1306

  38. IMPROVEMENT OF ADHESION STRENGTH OF THE COPPER NANOWIRE SURFACE FASTENER BY INVESTIGATING THE DIAMETER RATIO OF NANOWIRES International conference

    Kato Motohiro, Toku Yuhki, Morita Yasuyuki, Ju Yang

    IRF2018: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON INTEGRITY-RELIABILITY-FAILURE 

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    Event date: 2018

    Language:English   Presentation type:Oral presentation (general)  

  39. Nanoscroll Formation of Metal-coated Nanobelt with Residual Stress Induced in Coating Film

    TOGAWA Yosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In recent years, various nanomaterials have been studied and a wide variety of applications have been attracted as the outcome of nanotechnology development. As research progresses, it can be expected that nanomachine technology will be a future subject. In this case a nanoscale power source is necessary, but it has not yet been put to practical use. Therefore, we propose a nanoscroll as a new nanoscale energy storage device. The advantage of nanoscroll is that they can storage energy with high efficiency and high density, and can be used as actuators by a simple procedure. We have built up a new material processing method for bending deformation of nanomaterials. In previous study, we succeeded in forming nanocoils by applying this method to nanowires. In this study, we tried to create nanoscroll by applying it to nanobelt. We achieved creating the shape with different curvatures at the tip and root of the nanobelt by nonuniformly sputtering in longitudinal direction. The deformation in the pitch direction was also suppressed.</p>

    DOI: 10.1299/jsmemecj.2017.J2220204

  40. Development of active targeting DDS using Fe<sub>3</sub>O<sub>4</sub>@mSiO<sub>2</sub>-tLyP-1 nanoparticles

    MORITA Yasuyuki, SAKURAI Ryohei, WAKIMOTO Takuma, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2017.29.2B35

  41. Measurement on dynamic invasive field induced by multi-tumor spheroids using DVC method

    NAKANO Yusuke, MORITA Yasuyuki, YAMAUCHI Takashi, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>When tumor cells metastasize, invasion of cells plays a major role. In particular, invasion of epithelial tumor cells is induced by performing epithelial-mesenchymal transition (EMT). EMT is a process that have high motility induced by external factors in which epithelial cells are transformed into mesenchymal cells. It is a very important process in invasion. The tumor cells generate forces during cell invasion through a three-dimensional (3D) matrix. Measuring the mechanics field generated in the Extracellular Matrix (ECM) surrounding the cells is an important way to understand the behavior of tumor cells in 3D environment. Therefore, in this study, spheroids, which are the source of the invasion for tumor cells, were embedded in a collagen gel, and the deformations of the collagen gel surrounding the spheroids were measured. Using the DVC method, the matrix deformations around spheroids were measured by tracking the 3D positions of fluorescent beads embedded in the collagen gel. In addition, we added TGF-β1 which facilitates the invasion of tumor cells, and the influence of TGF-β1 on the mechanical property of spheroids was quantitatively evaluated. As a result, it was found that the maximum displacement of spheroids treated with TGF-β1 is larger than that of the one's without TGF-β1 treatment.</p>

    DOI: 10.1299/jsmemm.2017.OS0113

  42. Fabrication of Photoelectrode Based on Cu<sub>2</sub>O/Cu Core-Shell Nanowires Array Used for Solar Water Splitting

    KASAHARA Ryutaro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>In recent days, hydrogen is considered as an alternative energy which could instead of the fossil fuel in the future. A new clean method to manufacture hydrogen gas is called solar water splitting. Cu<sub>2</sub>O is considered as a promising and attractive material for solar driven hydrogen production because the suitable band gap (ca. 2.0 eV) and the low cost. Based on the band gap, it can be calculated the maximum theoretical light-to-hydrogen conversion efficiency is 18% at AM 1.5 spectrum, and the theoretical photocurrent of 14.7 mA/cm<sup>2</sup>. However, the experimental conversion efficiency was much lower than the theoretical one, due to self-corrosion coinciding with water-splitting reaction and that an electron and a hole activated by the sun light irradiation are easily recombined in oxidation film. In this research, Cu<sub>2</sub>O/Cu core-shell Nanowire (NW) has been fabricated on the surface of the photoelectrode by the polycarbonate template method to increase the conversion efficiency by optimizing the NW structure. We have investigated the relationship between NW's structure and photocurrent density, as well as incident photo to current efficiency (IPCE). As a result, we find the optimum conditions of NW's diameter and oxidation time. The visible light responsiveness from IPCE results has also been confirmed.</p>

    DOI: 10.1299/jsmemm.2017.GS0301

  43. Measurement of 4D dynamics field in ECM surrounding tumor cells effected by epithelialmesenchymal transition using digital volume correlation method

    YAMAUCHI Takashi, MORITA Yasuyuki, TOKU Yuhki, JU Yang, KAWASE Naoki

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebio.2017.29.1F42

  44. Measurement of Intracellular Dynamic Field of a Stretched Cell Using Digital Image Correlation Mehtod

    UMEI Wataru, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemecj.2017.J0250205

  45. Improvement of Adhesive Strength of Nanowire Surface Fastener by the Optimization of Diameter Ratio of Nanowires

    KATO Motohiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Lead-free solder has been used for surface mounting of electronic devices in consideration of the environment. However, there is a concern that the electronic parts may be damaged by heating during bonding because the lead-free solder has a high melting point. Therefore, development of a new bonding technique without heating is required. There are many studies on nanowires because of their unique characteristics which are different from bulk materials. In this paper, we fabricated Cu nanowire surface fasteners and investigated the improvement of strength by changing the diameter ratio of nanowires. Cr and Au films were formed as electrodes on glass substrates by sputtering. According to the template method, the polycarbonate template was fixed on one electrode to fabricate Cu nanowires by electrodepositing in the CuSO<sub>4</sub>·5H<sub>2</sub>O solution. After removing the template by etching with dichloromethane, the Cu nanowire surface fastener was fabricated. By applying a preload, the Cu nanowire surface fasteners were connected. Thereafter, the adhesion strength of the Cu nanowire surface fastener was evaluated by a tensile test. The highest bonding strength was found to be 162.6 N/cm<sup>2</sup> while the combination of the nanowire array with the diameter ratio of 1:4. Nanowires intertangling with each other was assumed to be an additional effect on the van der Waals force between nanowires.</p>

    DOI: 10.1299/jsmemecj.2017.J0330303

  46. Influence of Buffer Layers on the Piezoelectric Property of ZnO Film

    KAWAI Kota, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Three-dimensional manipulation is necessary to make assembly operations during fabricating micro/nano-scale devices. However, it is difficult to release the objects at nanoscale due to the adhesion force between object and manipulator. Some researchers have developed manipulation devices which can reduce the adhesion force by utilizing the inertial force generated by vibrating the microcantilever with a bulk piezoelectric material placed near the base of it. However, there is still a problem of size, and it has not been applied to a narrow space such as a scanning electron microscope chamber. In order to further downsize the manipulator, simplification of the manipulation devices by using thin film piezoelectric materials instead of bulk piezoelectric ones and directly attaching to the microcantilever is effective. In this case, it is important to select the buffer layer which is originally used for relaxing the lattice mismatch to enhance the piezoelectricity of the thin film. In this study, the influence of buffer layer on piezoelectric properties of ZnO thin film was investigated. The deflection was measured when AC voltage was applied to the cantilever fabricated with ZnO thin film and the cross section of the cantilever were observed. As a result, using the Cr buffer layer rather than using Al buffer layer, the average of the cantilever tip displacement at each applied voltage was approximately 6 times larger and the piezoelectricity of the ZnO thin film was improved.</p>

    DOI: 10.1299/jsmemecj.2017.J2220205

  47. Local Permittivity Evaluation Based on the Force Variation of Microwave Atomic Force Microscopy

    Bo TONG, Minji ZHAO, Yuhki TOKU, Yasuyuki MORITA, Yang JU

    The Proceedings of The Computational Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    Microwave atomic force microscopy (M-AFM) is designed to realize the non-contact measurement of topography and electrical property at nanoscale simultaneously. For the evaluation of dielectric materials, since the detected reflected signal depends strongly on the probe-sample distance, in non-contact mode the quantitative evaluation regardless of the effect of distance is difficult. In this study, the effect of microwave on the force between the probe and dielectric materials was investigated. A theoretic model based on the reflection of electromagnetic wave was established to describe the distance dependence of microwave intensity between sample and probe. The relationship between the force gradient and sample permittivity was obtained and the permittivity of Al<sub>2</sub>O<sub>3</sub>, Ge, and ZrO<sub>2</sub> was evaluated using this theoretical model.

    DOI: 10.1299/jsmecmd.2017.30.340

    CiNii Research

  48. Influence of cyclic uniaxial stretching frequency on hMSC-to-tenocyte differentiation

    HIRANO Yusho, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebiofro.2017.28.1A24

  49. Improving Adhesion Strength and Thermal Conductivity of Nanowire Surface Fastener

    NONOMURA Riku, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2017

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Solder has been used for the conventional bonding technology in electronic assembly for a long time. However, the traditional reflow soldering technique is characterized by high heating temperatures. Moreover, due to the progress of power devices, the working temperature in the electrical packages is increased. Therefore, we have proposed nanowire surface fastener (NSF) based on Cu nanowire arrays by which cold bonding for electrical packaging can be realized. Since copper is a high thermal conductive material, a satisfactory heat transfer characteristic is expected. In this paper, we investigated the improvements of the strength and thermal properties by changing the connecting load. The template method was used for fabricating Cu nanowire arrays, and the bonding strength of Cu NSF was evaluated by a tensile test. The highest bonding strength (205.06 N/cm<sup>2</sup>) was recorded when two nanowire arrays were connected by the connecting load of 125 N. Simultaneously, we measured the electrical resistance of Cu NSF by a four-terminal method. The electrical resistance showed the opposite behaviour to the bonding strength. Specifically, the larger connecting load we applied, the lower electrical resistance it showed. In metallic materials, since free electrons are carriers of the electric current and heat transfer, the electric conductivity and the thermal conductivity are closely related. Therefore, improvements of the electric and thermal conductivity are expected when electrical resistance decreases.</p>

    DOI: 10.1299/jsmemm.2017.OS1407

  50. Effect of pulsed electric current on the mechanical properties of titanium alloy International conference

    Jung J.

    ICF 2017 - 14th International Conference on Fracture 

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    Event date: 2017

    Language:English   Presentation type:Oral presentation (general)  

    Scopus

  51. カーボンナノチューブシートを用いた水素センサーの開発

    厳 可逸,徳 悠葵,森田 康之,巨 陽

    日本機械学会 第24回機械材料・材料加工技術講演会(M&P2016) 

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    Event date: 2016.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:早稲田大学   Country:Japan  

  52. ナノワイヤ面ファスナーのための低細孔密度ポーラスアルミナテンプレートの開発

    宋 揚,徳 悠葵,森田 康之,巨 陽

    日本機械学会 第24回機械材料・材料加工技術講演会(M&P2016) 

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    Event date: 2016.11

    Language:English   Presentation type:Oral presentation (general)  

    Venue:早稲田大学   Country:Japan  

  53. DVC 法を用いた幹細胞分化時における細胞外基質の 3 次元力学場計測

    山本 陵介,森田 康之,山内 崇司,徳 悠葵,巨 陽

    日本機械学会 M&M2016材料力学カンファレンス 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神戸大学   Country:Japan  

  54. Cu2O/Cu コアシェルナノ構造太陽電池のナノワイヤ密度が変換効率に与える影響

    松尾 亮佑,巨 陽,森田 康之,徳 悠葵

    日本機械学会 M&M2016材料力学カンファレンス 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神戸大学   Country:Japan  

  55. ストレスマイグレーションを利用した Al ナノワイヤの成長に及ぼす Al 薄膜構造の影響

    鈴木 崇真,徳 悠葵,森田 康之,巨 陽

    日本機械学会 M&M2016材料力学カンファレンス 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神戸大学   Country:Japan  

  56. マイクロ波が誘起する探針―試料間原子間力による局所誘電率評価

    チョウ ミンキ,徳 悠葵,森田 康之,巨 陽

    日本機械学会 M&M2016材料力学カンファレンス 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神戸大学   Country:Japan  

  57. マイクロ波原子間力顕微鏡を用いた局所導電率測定に及ぼす試料表面形状の影響

    波多野 貴大,徳 悠葵,森田 康之,巨 陽

    日本機械学会 M&M2016材料力学カンファレンス 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神戸大学   Country:Japan  

  58. マイクロ波を用いた熱可塑性炭素繊維強化プラスチックの繊維含有率測定技術の開発

    田所 昴,巨 陽,森田 康之,徳 悠葵

    日本機械学会 M&M2016材料力学カンファレンス 

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    Event date: 2016.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:神戸大学   Country:Japan  

  59. 熱疲労を受けるナノワイヤ面ファスナーの接続強度および電気的特性の評価

    徳 悠葵,野田 修二,森田 康之,巨 陽

    日本機械学会 第29回計算力学講演会 CMD2016 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:名古屋大学   Country:Japan  

  60. 薄膜残留応力を利用した被覆 Al ナノワイヤの自己変形

    上田 祐志,徳 悠葵,森田 康之,巨 陽

    日本機械学会 2016年度年次大会講演会 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:九州大学   Country:Japan  

  61. カーボンナノチューブ複合材料の強度向上に関 する実験的検討

    笠原龍太郎,徳 悠葵,森田 康之,巨 陽

    日本機械学会 2016年度年次大会講演会 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:九州大学   Country:Japan  

  62. 同軸構造を有するマイクロ波原子間力顕微鏡プローブの作製および評価

    平林 貴大,徳 悠葵,森田 康之,巨 陽

    日本機械学会 2016年度年次大会講演会 

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    Event date: 2016.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Venue:九州大学   Country:Japan  

  63. 機械的伸縮刺激による腱細胞分化に関する1細胞計測

    山下 貴大,森田 康之,徳 悠葵,巨 陽

    日本機械学会東海支部第65期総会・講演会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  64. マイクロビーズを利用したナノ多孔質膜の細孔密度の制御

    川島 大輝,巨 陽,森田 康之,徳 悠葵

    日本機械学会東海学生会第47回学生員卒業研究発表講演会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  65. 高密度電流印加がチタン合金の材料強度におよぼす影響

    稲留 義朗,徳 悠葵,森田 康之,巨 陽

    日本機械学会東海学生会第47回学生員卒業研究発表講演会 

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    Event date: 2016.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  66. Strain dependence of MSCs under cyclic stretch stimulus to form tendon tissue

    HIGASHIURA Kouji, MORITA Yasuyuki, SATO Toshihiro, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering 

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmebiofro.2016.27.B215

  67. Influence of the Cu<sub>2</sub>O/Cu Core-Shell Nanowires Density on Conversion Efficiency

    MATSUO Ryosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Currently, solar cells aremainlymade fromSi.However, due to the high cost and the limited resources of Si, new materials for solar cells are still needed. It has been proved that Cu<sub>2</sub>O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu<sub>2</sub>O solar battery is much lower than theoretical value. In this research, Cu<sub>2</sub>O/Cu core-shell NWs are fabricated on the surface of the solar cell by the AAO template method to increase light receiving area. As a result, we succeed in fabricating Cu<sub>2</sub>O/Cu core-shell NWs. The surface area of the solar cell is increased to about 151 times, which improve the solar energy conversion efficiency. And, we also find that the density of NWarrays effects the solar energy conversion efficiency.</p>

    DOI: 10.1299/jsmemm.2016.GS-40

  68. 312 Single-cell measurement on stem cell-to-tenocyte differentiation induced by cyclic stretch stimulation

    YAMASHITA Takahiro, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Conference of Tokai Branch 

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmetokai.2016.65._312-1_

  69. Fabrication of Carbon-Nanotube Sheet based Hydrogen Sensor

    YAN Keyi, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and processing conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>Due to their high specific surface area and measurable change in conductance according to the chemical environment changes, carbon nanotubes (CNTs) have been proved to be an ideal material for next generation of gas sensor. However, before CNTs-based sensor can become a candidate for commercial implementation, there are still challenges including mass production of sensor arrays and improvement of sensor reproducibility. In this research, a high sensitivity CNT sheet-based gas sensor was fabricated, which can push forward the commercialization of CNT-based sensor. By controlling the reaction conditions during chemical vapor deposition (CVD) process, a spinnable CNT array was synthesized reproducibly. The CNT sheets were drawn from a sidewall of spinnable CNT array. CNT sheets were directly fixed onto Au electrodes and were heated up to 300°C for 2 h to oxidize amorphous carbon. Gas detection toward hydrogen gas was operated in a quartz tube chamber. With the change of gas concentration, the change in sensor resistances as response and recovery behavior was measured using a programmable electrometer. A sensitivity of 5% for 4% H<sub>2</sub> was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H<sub>2</sub> gas at room temperature was achieved by Pd functionalization.</p>

    DOI: 10.1299/jsmemp.2016.24.406

    CiNii Research

  70. Rarefaction of Pore Density in Anodic Aluminum Oxide Nanoporous Membrane for the Fabrication of Nanowire Surface Fastener

    SONG Yang, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and processing conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmemp.2016.24.413

    CiNii Research

  71. 312 Single-cell measurement on stem cell-to-tenocyte differentiation induced by cyclic stretch stimulation

    YAMASHITA Takahiro, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Conference of Tokai Branch  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmetokai.2016.65._312-1_

    CiNii Research

  72. Fabrication and Evaluation of Microwave Atomic Force Microscope Probe Formed with Coaxial Structure

    HIRABAYASHI Takahiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>With the development of nanotechnology in recent years, many researchers have focused on the fabrication of nanomaterials and nanostructures. To apply these nanomaterials and nanostructures into electronic devices, there are great needs of quantitative measurement of electrical properties of them. To satisfy these demands, we have developed the measurement instrument named microwave atomic force microscopy (M-AFM). Special probes with two unique abilities which are transmitting and radiating the microwaves were used for M-AFM. To improve these abilities, the tip of the probe was changed from slit structure to coaxial one. In this paper the new process of fabrication of coaxial structured probes were described, and the results of M-AFM measurement on the Au/GaAs sample using former slit probe and developed coaxial probe were presented. M-AFM measurement using coaxial probe obtained the clearer image of microwave responses. Results of measurements indicated coaxial probes have higher resolution in electrical properties measurement.</p>

  73. Self-deformation of Coated Al Nanowires Induced by Residual Stress in Coating Film

    UEDA Yuji, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>Micro/nano coils have been expected to be utilized in various applications as small inductors. Various methods have been proposed for fabricating them. Most of these methods were based on self-assembly technique such as thermal sublimation and chemical vapor deposition. In our previous study, we proposed an alternative method based on a mechanical process, where a straight nanowire is bent by depositing a thin film with a circumferentially nonuniform thickness on the nanowire. The bending is due to the misfit strain of the coated film. In order to enhance the bending, we also adopted a heat treatment that induces a creep flow only in the nanowire and thereby released the constraint of the nanowire on elastic bending due to film strain. However, the shape control of micro/nano coils such as coil pitch and direction of helical deformation was still not succeeded. In present study, we investigated the effects of film thickness and nanowire position on the coil formation during coil formation in the sputtering chamber. We achieved the shape control of micro/nano coils by varying the film thickness and nanowire position.</p>

  74. Experimental Investigating Strength Improvement of Carbon Nanotube Composite Materials

    KASAHARA Ryutaro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>Carbon nanotube (CNT) composite materials are expected to be utilized in the field of aerospace and automobile industry due to their excellent mechanical property and relatively light weight. However, the experimental material strength measured from tensile test was much lower than the theoretical one calculated by simulation. In order to clarify the mechanism how CNT in the resin improves the material strength and increase experimental value, tensile tests and observation of fracture surface have been conducted in this research. Flaked composite material specimens with different local CNT content rates were prepared for tensile test. As a result of tensile test, we got material strength of flacked composite material specimens, which was approximately 2.5 times higher than that of only resin. By microscopic observation, we confirmed CNT pulled out from base material on fracture surface. In this research, we achieved that a higher local content rate of CNT leads to a higher experimental strength.</p>

  75. Connection Strength and Electrical Property of Nanowire Surface Fastener during Heat Fatigue Test

    TOKU Yuhki, NOTA Shuji, MORITA Yasuyuki, JU Yang

    The Proceedings of The Computational Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmecmd.2016.29.4_232

    CiNii Research

  76. The Effect of Al Film Structure on the Growth of Al Nanowires Based on Stress Migration

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>Nanowire (NW) is one-dimensional nanostructure with the diameter in nanoscale. Currently, we can fabricate NWs made from metal, metal oxide and semiconductor which could be utilized in various applications. In our previous study, we investigated a new fabrication method of Al NWs with high growth density by stress migration. It is generally known that Al is high conductivity and inexpensive material, therefore this method for mass production of Al NWs has a big advantage. However, the mechanism of fabrication has not been clear. In this study, we investigated the effect of surface roughness and etching depth induced by focused ion beam etching on the growth density of Al NWs. As a result, we found that etching depth strongly affects the growth density of Al NWs.</p>

  77. Local Permittivity Measurement Utilizing Atomic Force between Probe and Sample Caused by Microwave

    ZHAO Minji, TONG Bo, TOKU Yuki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>With the development of nanotechnology, different types of scanning probe microscopy (SPM) have been developed to satisfy the requirement of nanotechnology. The microwave detection system is combined on the atomic force microscopy (AFM) to evaluate the electrical properties of the materials simultaneously. It is found that when microwave is applied through the probe, the microwave has interaction with the material. In this paper, the mechanism of the interaction between the microwave and material is investigated. We evaluated the probes by the microwave atomic force microscope (M-AFM) and verified our theoretical work. The result implies that the interatomic force between the tip and sample can be utilized to evaluate the permittivity of semiconductor and insulator materials.</p>

  78. Influence of Material Surface on the Measurement of Local Electrical Conductivity using Microwave Atomic Force Microscopy

    HATANO Takahiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures. To apply these nanomaterials and nanostructures into nanodevices, the measurement technology for measuring electrical properties at high spatial resolution has been requested. Therefore, our group has developed Microwave Atomic Force Microscopy (M-AFM) in order to assess electrical conductivity in a minute area. This paper describes influence of material surface on the measurement of local electrical conductivity using M-AFM. Results of this experiment indicate actually that M-AFM can measure electrical conductivity in a local area accurately without being affected by the material surface.</p>

  79. Volume FractionMeasurement of Carbon Fiber Reinforced Thermoplastic by Microwaves

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    Event date: 2016

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    <p>Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof. CFRTP is used for structural members such as aircrafts, automobiles, blades of electricgenerating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in the guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reflection wave of the microwave. Using a theory model, the volume fraction was evaluated from the conductivity. As a result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.</p>

  80. ストレスマイグレーションによる単結晶 Al ナノワイヤの高密度生成

    鈴木 崇真,徳 悠葵,森田 康之,巨 陽

    日本機械学会 M&M2015材料力学カンファレンス 

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    Event date: 2015.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  81. コアシェルナノワイヤを用いた亜酸化銅太陽電池の作製および評価

    松尾 亮佑,徳 悠葵,森田 康之,巨 陽

    日本機械学会 M&M2015材料力学カンファレンス 

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    Event date: 2015.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  82. マイクロ波を利用した熱可塑性炭素繊維強化プラスチックの繊維含有率の定量評価

    田所昴,徳悠葵,森田康之,巨陽

    日本機械学会 M&M2015材料力学カンファレンス 

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    Event date: 2015.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  83. GS0705-431 Fabrication and Evaluation of Cu_2O Solar Cell with Core-Shell Nanowires

    MATSUO Ryosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2015  The Japan Society of Mechanical Engineers

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    Event date: 2015.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Currently, the solar cells are mainly made of silicon. However, due to the high cost and shortage of silicon, new materials for solar cells are still needed. It has been proved that Cu_2O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu_2O solar cell is much lower than theoretical one. In this research, Cu_2O/Cu core-shell nanowires are fabricated on the surface of the solar cell by the template method to increase light receiving area. Then, elemental analysis for core-shell nanowires is carried out by Electron Energy-Loss Spectroscopy. As a result, we succeed in fabricating Cu_2O/Cu core-shell nanowires. The area of the solar cells is increased to about 220 times, which is convinced to improve the solar energy conversion efficiency.

    DOI: 10.1299/jsmemm.2015._gs0705-43

    CiNii Research

  84. ナノ加工プロセスによるナノワイヤ群のフック形成に関する研究

    徳 悠葵,草間 美香,巨 陽

    日本機械学会機械材料・材料加工部門 第23回機械材料・材料加工技術講演会 

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    Event date: 2015.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  85. The shape control and performance evaluation of nanowire surface fastener International conference

    Mika KUSAMA, Yuhki TOKU, Yang JU

    The international conference on advanced technology in experimental mechanics 2015 and the 14th Asian conference on experimental mechanics  

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    Event date: 2015.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  86. マイクロ 波原子間力顕微鏡の探針先端における原子間力の評価

    一二三 和馬, 徳 悠葵, 巨 陽

    日本機械学会  2015年度年次大会 

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    Event date: 2015.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  87. 応力誘導法による三次元ナノ構造体の作製

    若林 信宏, 徳 悠葵,巨 陽

    日本機械学会  2015年度年次大会 

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    Event date: 2015.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  88. ストレスマイグレーションによる超高品質 Alナノワイヤの創製と電気的特性の評価

    柴田 貴俊,小島 直樹,徳 悠葵,巨 陽

    日本機械学会  2015年度年次大会 

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    Event date: 2015.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  89. コアシェルナノ構造を利用した原子拡散によるナノウィスカー生成に関する研究

    徳 悠葵,村岡 幹夫,巨 陽

    日本機械学会 材料力学部門 若手シンポジウム2015 

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    Event date: 2015.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  90. OS14-6 The Shape Control and Performance Evaluation of Nanowire Surface Fastener(Semiconductor Devices and Electronic Packaging 2,OS14 Electronic and photonic packages,APPLICATIONS) International conference

    Kusama Mika, Toku Yuhki, Ju Yang

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics 

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    Event date: 2015

    Language:English   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmeatem.2015.14.212

  91. J0610104 Evaluation of Interatomic Force on the Tip of Probe by using Microwave Atomic Force Microscope

    HIFUMI Kazuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures such as nanowires. To apply these nanomaterials and nanostructures into nanodevices, there are great needs of the quantitative measurement of electrical properties of materials in an infinitesimal area. Recently, it has been reported that the microwave gives an effect to an interatomic force in local area among materials. Therefore, it is thought that an identification of materials and an evaluation of electrical characteristics become possible by clarifying the relation between microwave and interatomic force. Therefore, we investigated interatomic force under the tip of probe by focusing on the force-distance curve measurement using microwave atomic force microscopy (M-AFM) as the first step. This paper describes the method and the results of the force-distance curve measurement on the sample of Au, Si, and glass. Results of this experiment indicate actually that the effect of microwave is large in material which has high electric conductivity.

    DOI: 10.1299/jsmemecj.2015._J0610104-

  92. GS0706-432 The Fabrication of High Density Single Crystal Al Nanowires by Stress Migration

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Nanowires have been expected to be utilized in various applications. Recently, many researchers have reported about single crystal or polycrystalline nanowires where the single crystal nanowires are shown to have a higher conductivity compared to the polycrystalline ones. In our previous study, we investigated the fabrication process of single crystal nanowires by stress migration. However, because the mechanism of fabrication was not clear, the generation density of single crystal nanowires was low for this method. In this study, we suggested a new method to increase the generation density of single crystal nanowires. An etching process was added to the previous fabrication method and the conditions of the substrate surface were changed. By doing this, the stress generated around the concentrated Al atoms was larger than the threshold stress needed to fabricate the nanowires. As a result of the added etching process, we achieved a nanowire generation density 100 times that of the conventional fabrication method.

    DOI: 10.1299/jsmemm.2015._GS0706-43

  93. F041003 Development of Functional Nanowire Surface Fastener Invited

    JU Yang, TOKU Yuhki

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we introduce a new patterned structure of nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized. The mechanical bonding enables normal and shear bonding strengths of more than 5 N/cm^2. Simultaneously, the parasitic resistance of a pair of surface fasteners is only approximately 2Ω. The present technique can be performed at room temperature, thereby improving the process compatibility and reliability of SMDs. Surface fasteners based on high melting point metallic nanowires are temperature-resistant for many critical applications. In addition, bonding without solder material is positive for the recycling of rare metals in SMDs.

    DOI: 10.1299/jsmemecj.2015._F041003-1

  94. 722 Fabrication of Hook Nanowire Surface by Mechanical Bending

    TOKU Yuhki, KUSAMA Mika, JU Yang

    The Proceedings of the Materials and processing conference 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemp.2015.23._722-1_

  95. OS0409-433 Quantitative Measurement of Volume Fraction of the Carbon Fiber Reinforced Thermoplastic by Microwaves

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof CFRTP is used for structural members such as aircrafts, automobiles, blades of electric-generating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in quality control and a guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reply of the reflection wave of the microwave. And using a theory model, the volume fraction was evaluated from the conductivity. As the result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.

    DOI: 10.1299/jsmemm.2015._OS0409-43

  96. J0610105 Fabrication of Ultra-High Quality Al Nanowires Based on Stress-induced Method and Evaluation of Their Electrical Properties

    SHIBATA Takatoshi, TOKU Yuhki, JU Yang, KOJIMA Naoki

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    We describe the result of the electrical conductivity measurement of single crystalline aluminum nanowires. These nanowires are fabricated by simply heating the Al samples in air. The growth mechanism is stress-induced migration. Four electrodes were patterned on nanowires by the photolithographic technique and we obtained the resistivity of nanowires by four-terminal measurement. The relationship between electrical conductivity and diameter was examined experimentally.

    DOI: 10.1299/jsmemecj.2015._J0610105-

  97. J2220204 Fabrication of Three Dimensional Nanostructures by Stress-induced Method

    WAKABAYASHI Nobuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan 

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    In this study. we suggested simple and easy fabrication technique of flowe-like nanomaterials called Nano Flower (NF) by stress-induced method. From the observation of NFs grown on substrates which have different surface conditions, growth of NFs is probably related to residual stress of surface of substrates. EDS analysis results show that NFs grow up by taking in atmospheric carbon dioxide. NFs are expected as application to carbon dioxide capture and storage.

    DOI: 10.1299/jsmemecj.2015._J2220204-

  98. OS0409-433 Quantitative Measurement of Volume Fraction of the Carbon Fiber Reinforced Thermoplastic by Microwaves

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2015  The Japan Society of Mechanical Engineers

     More details

    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof CFRTP is used for structural members such as aircrafts, automobiles, blades of electric-generating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in quality control and a guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reply of the reflection wave of the microwave. And using a theory model, the volume fraction was evaluated from the conductivity. As the result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.

  99. F041003 Development of Functional Nanowire Surface Fastener

    JU Yang, TOKU Yuhki

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

     More details

    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we introduce a new patterned structure of nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized. The mechanical bonding enables normal and shear bonding strengths of more than 5 N/cm^2. Simultaneously, the parasitic resistance of a pair of surface fasteners is only approximately 2Ω. The present technique can be performed at room temperature, thereby improving the process compatibility and reliability of SMDs. Surface fasteners based on high melting point metallic nanowires are temperature-resistant for many critical applications. In addition, bonding without solder material is positive for the recycling of rare metals in SMDs.

    DOI: 10.1299/jsmemecj.2015._f041003-1

    CiNii Research

  100. J0610104 Evaluation of Interatomic Force on the Tip of Probe by using Microwave Atomic Force Microscope

    HIFUMI Kazuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

     More details

    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures such as nanowires. To apply these nanomaterials and nanostructures into nanodevices, there are great needs of the quantitative measurement of electrical properties of materials in an infinitesimal area. Recently, it has been reported that the microwave gives an effect to an interatomic force in local area among materials. Therefore, it is thought that an identification of materials and an evaluation of electrical characteristics become possible by clarifying the relation between microwave and interatomic force. Therefore, we investigated interatomic force under the tip of probe by focusing on the force-distance curve measurement using microwave atomic force microscopy (M-AFM) as the first step. This paper describes the method and the results of the force-distance curve measurement on the sample of Au, Si, and glass. Results of this experiment indicate actually that the effect of microwave is large in material which has high electric conductivity.

    DOI: 10.1299/jsmemecj.2015._j0610104-

    CiNii Research

  101. J0610105 Fabrication of Ultra-High Quality Al Nanowires Based on Stress-induced Method and Evaluation of Their Electrical Properties

    SHIBATA Takatoshi, TOKU Yuhki, JU Yang, KOJIMA Naoki

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

     More details

    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    We describe the result of the electrical conductivity measurement of single crystalline aluminum nanowires. These nanowires are fabricated by simply heating the Al samples in air. The growth mechanism is stress-induced migration. Four electrodes were patterned on nanowires by the photolithographic technique and we obtained the resistivity of nanowires by four-terminal measurement. The relationship between electrical conductivity and diameter was examined experimentally.

    DOI: 10.1299/jsmemecj.2015._j0610105-

    CiNii Research

  102. J2220204 Fabrication of Three Dimensional Nanostructures by Stress-induced Method

    WAKABAYASHI Nobuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

     More details

    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    In this study. we suggested simple and easy fabrication technique of flowe-like nanomaterials called Nano Flower (NF) by stress-induced method. From the observation of NFs grown on substrates which have different surface conditions, growth of NFs is probably related to residual stress of surface of substrates. EDS analysis results show that NFs grow up by taking in atmospheric carbon dioxide. NFs are expected as application to carbon dioxide capture and storage.

    DOI: 10.1299/jsmemecj.2015._j2220204-

    CiNii Research

  103. 722 Fabrication of Hook Nanowire Surface by Mechanical Bending

    TOKU Yuhki, KUSAMA Mika, JU Yang

    The Proceedings of the Materials and processing conference  2015  The Japan Society of Mechanical Engineers

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    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmemp.2015.23._722-1_

    CiNii Research

  104. GS0706-432 The Fabrication of High Density Single Crystal Al Nanowires by Stress Migration

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2015  The Japan Society of Mechanical Engineers

     More details

    Event date: 2015

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    Nanowires have been expected to be utilized in various applications. Recently, many researchers have reported about single crystal or polycrystalline nanowires where the single crystal nanowires are shown to have a higher conductivity compared to the polycrystalline ones. In our previous study, we investigated the fabrication process of single crystal nanowires by stress migration. However, because the mechanism of fabrication was not clear, the generation density of single crystal nanowires was low for this method. In this study, we suggested a new method to increase the generation density of single crystal nanowires. An etching process was added to the previous fabrication method and the conditions of the substrate surface were changed. By doing this, the stress generated around the concentrated Al atoms was larger than the threshold stress needed to fabricate the nanowires. As a result of the added etching process, we achieved a nanowire generation density 100 times that of the conventional fabrication method.

    DOI: 10.1299/jsmemm.2015._gs0706-43

    CiNii Research

  105. 金属被覆により生じるナノワイヤの曲げ変形に関する理論解析

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会 

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    Event date: 2014.7

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  106. OS1507 Investigating Effect of Film Thickness on Bending Deformation of Metal-Coated Nanowires

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and Mechanics Conference  2014  The Japan Society of Mechanical Engineers

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    Event date: 2014

    Language:Japanese   Presentation type:Oral presentation (general)  

    In this study, we discussed about the effect of film thickness on bending deformation of coated nanowire (NW). The three dimensional theoretical model for analyzing the effect was proposed in this paper. The dependence of the misfit strain on the film thickness was introduced in the model. We concluded that bending direction of the NW varied with increasing the coating film thickness. This result arises from the dependence of the misfit strain on the film thickness and the nonuniform film thickness along the circumference of the NW.

    DOI: 10.1299/jsmemm.2014._os1507-1_

    CiNii Research

  107. 金属被覆ナノワイヤの通電による形態変化の観察

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会 

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    Event date: 2013.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  108. 211 Theoretical Analysis for Helical Formation of Coated Nanowire by Viscous Flow of Core Material

    KUDO Ryusuke, TOKU Yuhki, MURAOKA Mikio

    The Proceedings of Autumn Conference of Tohoku Branch  2013  The Japan Society of Mechanical Engineers

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    Event date: 2013.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmetohoku.2013.49.51

    CiNii Research

  109. コア流動法により作製した金属被覆マイクロコイルの発生磁場評価

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会 

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    Event date: 2013.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  110. 511 Observation of Topological Change of Metal-Coated Nanowire under Current Supply

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and processing conference  2013  The Japan Society of Mechanical Engineers

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    Event date: 2013

    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemp.2013.21._511-1_

    CiNii Research

  111. 330 Helical Formation of Metal-Coated Nanowires by Core Reduction to Release Residual Stress

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and processing conference  2012  The Japan Society of Mechanical Engineers

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    Event date: 2012.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmemp.2012.20._330-1_

    CiNii Research

  112. 振動慣性力を利用したナノワイヤの付着力制御

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会 

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    Event date: 2012.8

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  113. Manipulation of Nanowires by Chopsticks International conference

    Kohtaro KOBAYASHI, Yuhki TOKU, Mikio MURAOKA

    International Conference on Advanced Technology in Experimental Mechanics 2011 

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    Event date: 2011.9

    Language:English   Presentation type:Oral presentation (general)  

    Country:Japan  

  114. Effect of Film Thickness on Helical Formation of Coated Nanowires in an Enhanced-Bending Technique International conference

    Yuhki TOKU, Mikio MURAOKA

    JSME/ASME 2011 International conference on materials & processing 

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    Event date: 2011.6

    Language:English   Presentation type:Oral presentation (general)  

    Country:United States  

  115. OS06-2-4 Manipulation of Nanowires by Chopsticks International conference

    Kobayashi Kohtaro, Toku Yuhki, Muraoka Mikio

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2011 

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    Event date: 2011

    Language:English   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmeatem.2011.10._OS06-2-4-

  116. Enhanced Bending of Coated Nanowires Using Viscous Flow of Core Material: Production of Nanoinductance International conference

    Yuhki TOKU, Mikio MURAOKA

    12th International Conference on Electronics Materials and Packaging 

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    Event date: 2010.10

    Language:English   Presentation type:Oral presentation (general)  

    Country:Singapore  

  117. 製膜ひずみとコア流動を利用した金属被覆ナノワイヤの曲げ加工

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会 

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    Event date: 2010.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  118. 002 Bend Processing of Metal-Coated Nanowires by Viscous Flow of Core Material and Intrinsic Strain of Coating Film

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and Mechanics Conference  2010  The Japan Society of Mechanical Engineers

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    Event date: 2010.10

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    Various methods have been proposed for fabricating nanocoils in order to extend the range of elements for building nanodevices. Most of these methods are based on self-assembly technique. We have previously demonstrated an alternative method in which a straight nanowire is bent by depositing a thin film on the nanowire. The bending is due to the misfit strain of the coated film. However, nanocoil formation using this method is highly inefficient. In this study, we developed an advanced method in which the helical formation of coated nanowires takes place because of the viscous flow of the core material, i.e., the nanowires, and the misfit strain of the coating film. When the melting temperature of the nanowire material is lower than that of the coating, elevating the temperature induces a viscous flow, i.e., creep, which only occurs in the nanowire. The creep releases the constraint of the nanowire on elastic bending due to film strain.

    DOI: 10.1299/jsmemm.2010.258

    CiNii Research

  119. T0301-1-4 Curvature Control of Nanocoils Produced by Viscous Flow of Core Material

    TOKU Yuhki, MURAOKA Mikio

    The proceedings of the JSME annual meeting  2010  The Japan Society of Mechanical Engineers

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    Event date: 2010.9

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    Various methods have been proposed for fabricating nanocoils in order to extend the range of elements for building nanodevices. Most of these methods are based on self-assembly technique. We have previously demonstrated an alternative method in which a straight nanowire is bent by depositing a thin film on the nanowire. The bending is due to the misfit strain of the coated film. However, nanocoil formation using this method is highly inefficient. In this study, we developed an advanced method in which the helical formation of coated nanowires takes place because of the viscous flow of the core material, i.e., the nanowires, and the misfit strain of the coating film. When the melting temperature of the nanowire material is lower than that of the coating, elevating the temperature induces a viscous flow, i.e., creep, which only occurs in the nanowire. The creep releases the constraint of the nanowire on elastic bending due to film strain.

    DOI: 10.1299/jsmemecjo.2010.8.0_173

    CiNii Research

  120. 104 Herical Formation of Metal-Coated Nanowires by Viscous Flow of the Core Material

    TOKU Yuki, MURAOKA Mikio

    The Proceedings of Conference of Tohoku Branch  2010  The Japan Society of Mechanical Engineers

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    Event date: 2010.3

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

    DOI: 10.1299/jsmeth.2010.45.12

    CiNii Research

  121. ナノワイヤの真性ひずみ誘起曲げ加工条件の実験的検討

    徳 悠葵, 村岡 幹夫

    精密工学会東北支部学術講演会 

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    Event date: 2009.11

    Language:Japanese   Presentation type:Oral presentation (general)  

    Country:Japan  

  122. ストレスマイグレーションによる単結晶 Al ナノワイヤの高密度生成 International conference

    鈴木 崇真, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 M&M2015材料力学カンファレンス  2015.11.21 

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    Language:Japanese   Presentation type:Oral presentation (general)  

  123. コアシェルナノワイヤを用いた亜酸化銅太陽電池の作製および評価 International conference

    松尾 亮佑, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 M&M2015材料力学カンファレンス  2015.11.21 

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    Language:Japanese   Presentation type:Oral presentation (general)  

  124. Experimental Investigating Strength Improvement of Carbon Nanotube Composite Materials International conference

    KASAHARA Ryutaro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of Mechanical Engineering Congress, Japan

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    Language:Japanese   Presentation type:Oral presentation (general)  

    <p>Carbon nanotube (CNT) composite materials are expected to be utilized in the field of aerospace and automobile industry due to their excellent mechanical property and relatively light weight. However, the experimental material strength measured from tensile test was much lower than the theoretical one calculated by simulation. In order to clarify the mechanism how CNT in the resin improves the material strength and increase experimental value, tensile tests and observation of fracture surface have been conducted in this research. Flaked composite material specimens with different local CNT content rates were prepared for tensile test. As a result of tensile test, we got material strength of flacked composite material specimens, which was approximately 2.5 times higher than that of only resin. By microscopic observation, we confirmed CNT pulled out from base material on fracture surface. In this research, we achieved that a higher local content rate of CNT leads to a higher experimental strength.</p>

  125. カーボンナノチューブ複合材料の強度向上に関 する実験的検討 International conference

    笠原龍太郎, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 2016年度年次大会講演会  2016.9 

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    Venue:九州大学  

  126. Fabrication of Carbon-Nanotube Sheet based Hydrogen Sensor International conference

    YAN Keyi, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of the Materials and processing conference

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    <p>Due to their high specific surface area and measurable change in conductance according to the chemical environment changes, carbon nanotubes (CNTs) have been proved to be an ideal material for next generation of gas sensor. However, before CNTs-based sensor can become a candidate for commercial implementation, there are still challenges including mass production of sensor arrays and improvement of sensor reproducibility. In this research, a high sensitivity CNT sheet-based gas sensor was fabricated, which can push forward the commercialization of CNT-based sensor. By controlling the reaction conditions during chemical vapor deposition (CVD) process, a spinnable CNT array was synthesized reproducibly. The CNT sheets were drawn from a sidewall of spinnable CNT array. CNT sheets were directly fixed onto Au electrodes and were heated up to 300°C for 2 h to oxidize amorphous carbon. Gas detection toward hydrogen gas was operated in a quartz tube chamber. With the change of gas concentration, the change in sensor resistances as response and recovery behavior was measured using a programmable electrometer. A sensitivity of 5% for 4% H<sub>2</sub> was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H<sub>2</sub> gas at room temperature was achieved by Pd functionalization.</p>

  127. カーボンナノチューブシートを用いた水素センサーの開発 International conference

    厳 可逸, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 第24回機械材料・材料加工技術講演会(M&P2016)  2016.11 

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    Venue:早稲田大学  

  128. Development of Flexible Transparent Conductive Film with Carbon Nanotube Sheet International conference

    TAGUCHI Takuto, KIMURA Yasuhiro, TOKU Yuhki, JU Yan

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>In Recent years, the demand of transparent conductive films (TCFs) has been increased widely due to the potential application for electronic devices, such as touch panels, liquid crystal displays, and transparent electrodes. With the development of flexible devices, TCFs are required to be flexible. However, indium tin oxide (ITO), the most widespread material used for TCFs, is brittle ceramic material and expensive. Therefore, instead of ITO, TCF materials have to be flexible and low cost. Multiwalled carbon nanotubes (CNT) sheet has been studied as a replacement for ITO owing to its flexibility and low cost. However, the sheet resistance of CNT sheet is still higher than that of ITO: the values of 1000to 1500 Ω/□. One of the reasons is the contact resistance of each other of CNTs in a CNT sheet. In this study, metal nanoparticles were coated on the CNT sheet to reduce the contact resistance. After being coated with Cu/Ni, the contact resistance was modified and the sheet resistance was reduced to 300 Ω/□ or less, while the transmittance at the wave length of 550 nm maintains 80 % or higher. The results provide that CNT sheet is a promising candidate for flexible TCF material, realizing more effective production at lower cost than ITO.</p>

  129. Improving spinnability of carbon nanotube sheet by controlling the density and alignment of carbon nanotube array International conference

    TAGUCHI Takuto, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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  130. The effect of cancer assisted fibroblasts on mechanical field of cancer invasion International conference

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2019  The Japan Society of Mechanical Engineers

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  131. Experimental study on influence of ECM elasticity on invasive behavior of tumor cells International conference

    USHIDA Masato, MORITA Yasuyuki, OSHIMA Kanau, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2019  The Japan Society of Mechanical Engineers

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    <p>Cancer cells are known to lead human death, but they are difficult to treat. The reason is that the mechanism of metastasis has not been elucidated. Since cancer cells are known to induce the hardening and moving surrounding tissues i.e. extracellular matrix (ECM), this study aimed to increase the elastic modulus of ECM without changing the density of collagen fibers. The crosslinking agent (EDCNHS) was used for this purpose. By making collagen gel with administering the crosslinking agent, it was succeeded to increase the elastic modulus of ECM up to 5 times approximately than the case without crosslinking agent. Based on this result, it is possible to observe the infiltration behavior of cancer cells with the difference of elastic modulus under three-dimensional culture by enclosing cancer cells in the collagen gel.</p>

  132. Experimental study on the stress state of 3D ECM at the start of invasion of cancer spheroids International conference

    NAKANO Yusuke, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>When tumor cells metastasize, invasion of cells plays a major role. The tumor cells initiate invasion by generating force and changing the physical structure of the extracellular matrix (ECM) surrounding the tumor. However, the detail process of changing the structure of the ECM has not been elucidated. At this time, measuring the mechanics field generated in the ECM is an important way to understand behavior of tumor cells in 3D. Therefore, in this study, spheroids, which are the source of the invasion as a tumor cells, were embedded in a collagen gel, and the deformations of the collagen gel surrounding the spheroids were measured. Using the DVC method, the matrix deformations around spheroids were measured by tracking the 3D positions of fluorescent beads embedded in the collagen gel. To photograph the initial state of the ECM, we added tritonX-100 to the spheroid at the end of the experiment and photographed the state of no stress from the spheroid. In addition, we calculated the divergence of the deformations field and discussed on density change of ECM. As a result, it was found that spheroids systematically generate the deformation field and change the density of ECM. It was suggested that invasion occurs in the low density part.</p>

  133. Measurement of 4D dynamics field in ECM surrounding tumor cells effected by epithelialmesenchymal transition using digital volume correlation method International conference

    YAMAUCHI Takashi, MORITA Yasuyuki, TOKU Yuhki, JU Yang, KAWASE Naoki

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2017  The Japan Society of Mechanical Engineers

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  134. Control of Shape and Density of SnO<sub>2</sub> Nanobelt International conference

    TOGAWA Yosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>In recent years, various nanostructure materials such as nanowires, nanorods and nanobelts have been studied widely due to their excellent properties. Especially, much attention was paid by researchers in the preparation of oxide nanostructure materials due to their good optical and electrical properties. Numerous oxide nanostructure materials were synthesized so far, among which SnO<sub>2</sub> is considered to be an important one, because it is a typical n-type semiconductor. Particularly, SnO<sub>2</sub> nanobelts exhibited extensive optoelectronic and gas-sensitive properties which make them being excellent candidates for a wide range of applications such as gas sensors and transparent conductive film. SnO<sub>2</sub> nanobelt is generally synthesized by thermal evaporation method, but it is difficult to control the shape, size and density of SnO<sub>2</sub> nanobelts in the thermal evaporation process. However, since the elastic modulus and conductivity of the nanobelt depend on its shape and size, it is important to control shape and size of nanobelt. Hence, in this study, we adjusted experimental parameters such as pressure during heating and concentrations of gold nanoparticle solution to control the shape and size of nanobelts. From the scanning electron microscope image, we found that the aspect ratio of cross-section was controlled by pressure during heating. The results show that we succeeded in controlling the aspect ratio of cross-section and density of the SnO<sub>2</sub> nanobelts. From the above, it is expected that the improvement of flexibility and transparency of a transparent conductive film could be realized.</p>

  135. Influence of Thermal Fatigue on the Connection Strength of Nanowire Surface Fastener

    Y. Toku, S. Nota, Y. Morita, Y. Ju

    International multi-conference on engineering and technology innovation 2015  2016.8 

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    Venue:New York, USA  

  136. Improvement of Thin Film Adhesion Strength via Current Application

    Y. Toku, K. Kizawa, K. Sugiura, Y. Morita, Y. Ju

    Asia-Pacific Conference on Fracture and Strength 2018  2018.10 

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    Venue:Xi'an, China  

  137. IMPROVEMENT OF ADHESION STRENGTH OF THE COPPER NANOWIRE SURFACE FASTENER BY INVESTIGATING THE DIAMETER RATIO OF NANOWIRES

    Kato Motohiro, Toku Yuhki, Morita Yasuyuki, Ju Yang

    IRF2018: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON INTEGRITY-RELIABILITY-FAILURE  2018 

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  138. GS0705-431 Fabrication and Evaluation of Cu_2O Solar Cell with Core-Shell Nanowires International conference

    MATSUO Ryosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    2015.11.21  The Japan Society of Mechanical Engineers

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    Currently, the solar cells are mainly made of silicon. However, due to the high cost and shortage of silicon, new materials for solar cells are still needed. It has been proved that Cu_2O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu_2O solar cell is much lower than theoretical one. In this research, Cu_2O/Cu core-shell nanowires are fabricated on the surface of the solar cell by the template method to increase light receiving area. Then, elemental analysis for core-shell nanowires is carried out by Electron Energy-Loss Spectroscopy. As a result, we succeed in fabricating Cu_2O/Cu core-shell nanowires. The area of the solar cells is increased to about 220 times, which is convinced to improve the solar energy conversion efficiency.

  139. Development of active targeting DDS using Fe<sub>3</sub>O<sub>4</sub>@mSiO<sub>2</sub>-tLyP-1 nanoparticles International conference

    MORITA Yasuyuki, SAKURAI Ryohei, WAKIMOTO Takuma, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2017  The Japan Society of Mechanical Engineers

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  140. Evaluation of Local Dielectric Constant of Biomaterial Based on the Force-distance-curve Measured by Microwave Atomic-force Microscope International conference

    Zhao M

    MHS 2018 - 2018 29th International Symposium on Micro-NanoMechatronics and Human Science  2018.12 

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  141. ELECTROMAGNETIC PERFORMANCE OF SPIRALLY DEFORMED COATED NANOWIRES

    Y. Toku, Y. Ueda, Y. Morita, Y. Ju

    Recent Developments in Integrity - Reliability - Failure  2018.7 

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    Venue:Lisbon, Portugal  

  142. Effect of pulsed electric current on the mechanical properties of titanium alloy

    Jung J

    ICF 2017 - 14th International Conference on Fracture  2017 

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  143. Measurement on dynamic invasive field induced by multi-tumor spheroids using DVC method International conference

    NAKANO Yusuke, MORITA Yasuyuki, YAMAUCHI Takashi, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>When tumor cells metastasize, invasion of cells plays a major role. In particular, invasion of epithelial tumor cells is induced by performing epithelial-mesenchymal transition (EMT). EMT is a process that have high motility induced by external factors in which epithelial cells are transformed into mesenchymal cells. It is a very important process in invasion. The tumor cells generate forces during cell invasion through a three-dimensional (3D) matrix. Measuring the mechanics field generated in the Extracellular Matrix (ECM) surrounding the cells is an important way to understand the behavior of tumor cells in 3D environment. Therefore, in this study, spheroids, which are the source of the invasion for tumor cells, were embedded in a collagen gel, and the deformations of the collagen gel surrounding the spheroids were measured. Using the DVC method, the matrix deformations around spheroids were measured by tracking the 3D positions of fluorescent beads embedded in the collagen gel. In addition, we added TGF-β1 which facilitates the invasion of tumor cells, and the influence of TGF-β1 on the mechanical property of spheroids was quantitatively evaluated. As a result, it was found that the maximum displacement of spheroids treated with TGF-β1 is larger than that of the one's without TGF-β1 treatment.</p>

  144. DVC 法を用いた幹細胞分化時における細胞外基質の 3 次元力学場計測 International conference

    山本 陵介, 森田 康之, 山内 崇司, 徳 悠葵, 巨 陽

    日本機械学会 M&M2016材料力学カンファレンス  2016.10 

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    Venue:神戸大学  

  145. DVC Measurement on the Deformation Field of ECM Surrounding a Tumor Spheroid During the Invasive Progression

    Morita Yasuyuki, Nakano Yusuke, Oshima Kanau, Toku Yuhki, Ju Yang

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2019 

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  146. Development of Cu2O 3D nanostructure used for photo electrode of solar water splitting International conference

    IZUMI Yuri, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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  147. Enhancement of Solar-to-hydrogen Conversion Efficiency in Water Splitting by Optimizing Morphology of Cu<sub>2</sub>O Nanostructure and Surface Modification International conference

    IZUMI Yuri, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Recently, Cu<sub>2</sub>O has been considered as an attractive material for solar water splitting due to its excellent characteristics such as small bandgap, visible light adsorption, abundance, and nontoxicity. The theoretical solar-to-hydrogen conversion efficiency (STH) of Cu<sub>2</sub>O is 18% for water splitting. To date, the value experimentally obtained by previous works has not attained and overcomed above ideal value, because of the lack of Cu<sub>2</sub>O in photocathode to absorb sunlight efficiently, the short diffusion length of minority cariers, and the Cu<sub>2</sub>O photocorrosion during water splitting. 3D nanostructures for water splitting and surface modification contribute to resolving these issues. Nanostructures can improve STH owing to high surface-to-volume ratio and short diffusion length for carrier transport compared with bulk materials. In addition, surface modification enables to promote the separation of photogenerated electron-hole pair and to protect the photoelectrode against photocorrosion, and thus resulting in the enhancement of stability in Cu<sub>2</sub>O photocathode. The present study aimed to improve STH and stability in Cu<sub>2</sub>O photocathode for water splitting by optimizing morphology of Cu<sub>2</sub>O nanostructures and surface modification. In order to determine the suitable conditions for water splitting, the relationship between the morphology of the structure and STH was examined. The photocathode with Cu<sub>2</sub>O nanostructures exhibited maximum photocurrent density of 4.58 mA/cm<sup>2</sup> at a potential of 0 V vs. reversible hydrogen electrode (RHE) and STH of 5.63%. Besides, surface modification was successfully introduced by covering nanostructures with homogeneous and conformal layers formed by atomic layer deposition (ALD).</p>

  148. Influence of the Cu<sub>2</sub>O/Cu Core-Shell Nanowires Density on Conversion Efficiency International conference

    MATSUO Ryosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    <p>Currently, solar cells aremainlymade fromSi.However, due to the high cost and the limited resources of Si, new materials for solar cells are still needed. It has been proved that Cu<sub>2</sub>O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu<sub>2</sub>O solar battery is much lower than theoretical value. In this research, Cu<sub>2</sub>O/Cu core-shell NWs are fabricated on the surface of the solar cell by the AAO template method to increase light receiving area. As a result, we succeed in fabricating Cu<sub>2</sub>O/Cu core-shell NWs. The surface area of the solar cell is increased to about 151 times, which improve the solar energy conversion efficiency. And, we also find that the density of NWarrays effects the solar energy conversion efficiency.</p>

  149. Fabrication of Photoelectrode Based on Cu<sub>2</sub>O/Cu Core-Shell Nanowires Array Used for Solar Water Splitting International conference

    KASAHARA Ryutaro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>In recent days, hydrogen is considered as an alternative energy which could instead of the fossil fuel in the future. A new clean method to manufacture hydrogen gas is called solar water splitting. Cu<sub>2</sub>O is considered as a promising and attractive material for solar driven hydrogen production because the suitable band gap (ca. 2.0 eV) and the low cost. Based on the band gap, it can be calculated the maximum theoretical light-to-hydrogen conversion efficiency is 18% at AM 1.5 spectrum, and the theoretical photocurrent of 14.7 mA/cm<sup>2</sup>. However, the experimental conversion efficiency was much lower than the theoretical one, due to self-corrosion coinciding with water-splitting reaction and that an electron and a hole activated by the sun light irradiation are easily recombined in oxidation film. In this research, Cu<sub>2</sub>O/Cu core-shell Nanowire (NW) has been fabricated on the surface of the photoelectrode by the polycarbonate template method to increase the conversion efficiency by optimizing the NW structure. We have investigated the relationship between NW's structure and photocurrent density, as well as incident photo to current efficiency (IPCE). As a result, we find the optimum conditions of NW's diameter and oxidation time. The visible light responsiveness from IPCE results has also been confirmed.</p>

  150. Cu2O/Cu コアシェルナノ構造太陽電池のナノワイヤ密度が変換効率に与える影響 International conference

    松尾 亮佑, 巨 陽, 森田 康之, 徳 悠葵

    日本機械学会 M&M2016材料力学カンファレンス  2016.10 

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    Venue:神戸大学  

  151. Three-Dimensional Measurement of the Mechanical Fields and Fiber Structure around Cancer Cells Co-Cultured with CAFs International conference

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Invasion of cells plays a major role in metastasis. Cancer cells interact with cancer-associated fibroblasts (CAFs) present in the tumor microenvironment and as a result enhance their invasive ability. However, the overall mechanism of the interaction has not been clarified. When cancer cells moving, they constantly exert power on the surrounding extracellular matrix (ECM). In addition, the material properties of the ECM are not uniform because the fiber structure constantly changes. Therefore, measuring the mechanical field around cancer cells is significant in revealing the interaction between cancer cells and CAFs. In this study, we analyze what kind of change is caused in the mechanical field of ECM around a cancer cell by the effects of CAFs under three dimensional culture. We cultured the pancreatic ductal carcinoma cells, SUIT-2 with the orthotopic CAFs in collagen gel. Three-dimensional images were acquired by a confocal microscope. Embedding the fluorescent beads in the gel at the same time, the beads adhere to the collagen and form a pattern, therefore it is possible to track the displacement field by using the digital volume correlation (DVC) method. At the same time, the collagen fiber density and orientation were evaluated based on 3D images. As a result, accumulation and arrangement of collagen fibers were observed in the direction of CAF protrusion, and it became clear that cancer cells under the influence of CAFs generate a dynamic field in a wider range.</p>

  152. Mechanical Effects of CAFs on the Invasion Field of a Cancer Cell via Extracellular International conference

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2019  The Japan Society of Mechanical Engineers

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  153. 312 Single-cell measurement on stem cell-to-tenocyte differentiation induced by cyclic stretch stimulation International conference

    YAMASHITA Takahiro, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Conference of Tokai Branch  2016  The Japan Society of Mechanical Engineers

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  154. 312 Single-cell measurement on stem cell-to-tenocyte differentiation induced by cyclic stretch stimulation International conference

    YAMASHITA Takahiro, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Conference of Tokai Branch  2016  The Japan Society of Mechanical Engineers

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  155. ストレスマイグレーションを利用した Al ナノワイヤの成長に及ぼす Al 薄膜構造の影響 International conference

    鈴木 崇真, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 M&M2016材料力学カンファレンス  2016.10 

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    Venue:神戸大学  

  156. 高密度電流印加がチタン合金の材料強度におよぼす影響 International conference

    稲留 義朗, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会東海学生会第47回学生員卒業研究発表講演会  2016.3.16 

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  157. Improvement of adhesion strength of Au thin film by high-density electric current International conference

    KIZAWA Kurama, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and processing conference  2018  The Japan Society of Mechanical Engineers

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  158. Improvement of Mechanical Properties of Titanium alloy by High-Density Pulsed Electric Current International conference

    IWASE Rui, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Titanium alloys have been widely used in versatile productions due to their excellent mechanical properties. Conversely, the effective technique for the improvement of mechanical properties is required. Although heat treatment is used to enhance the mechanical properties, it increases processing cost. Recently, high-density pulsed electric current (HDPEC) has been studied for repairing defects and damages in metallic materials. Therefore, it would be expected to improve mechanical properties of Titanium alloy by applying HDPEC instead of heat treatment. This work studied the effect of HDPEC on the mechanical properties of Titanium alloy Ti-6Al-4V. Tensile test was conducted after applying HDPEC to the material. The application of HDPEC contributes to improve the elongation and tensile strength of 10% and 3.2% compared to unapplied ones, respectively. In addition, Vickers hardness was decreased with increasing current density. The change in the microstructure of the material before and after applying HDPEC was observed based on the X-ray diffraction analysis: The rate of <i>β</i>-phase in the material was increased by applying HDPEC. As a result, the mechanical properties of titanium alloy were improved by applying HDPEC due to the phase transformation.</p>

  159. Increase in Adhesion Strength of Au Thin Film via High-frequency and High-density Electric Current International conference

    KIZAWA Kurama, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>In recent years, electronic devices have remarkably achieved miniaturization and high performance with the development of MEMS. In addition, the current density in the interconnect has risen due to the increase of electric energy accompanying the development of power devices. The delamination of thin film due to thermal stress and electromigration has become a problem. One method to improve the adhesion strength of thin film on a substrate is using an adhesion layer such as Cr or Ti between the thin film and the substrate. However, this method has the disadvantages that additional materials are required and the thickness of the interconnect increases. The adhesion strength of the thin film needs to be improved itself. This study proposed a method to apply high-density current with high frequency to thin film to improve the adhesion strength of it. The Au thin film (Size: 5 mm×45 mm×150 nm) was deposited on a glass substrate by radio frequency sputtering. Then, high-density current with high frequency was applied in thin film and the adhesion strength was measured by using peel test. As a result, the adhesion strength was improved by 20% or greater by applying high-density current with high frequency. Therefore, this method is expected to be a new strength improvement method for thin film.</p>

  160. Improvement of mechanical properties of stainless steel alloy based on the electroplastic effect International conference

    IWASE Rui, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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  161. Strain dependence of MSCs under cyclic stretch stimulus to form tendon tissue International conference

    HIGASHIURA Kouji, MORITA Yasuyuki, SATO Toshihiro, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering  2016  The Japan Society of Mechanical Engineers

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  162. Optimization of Effective Parameters for Improving Adhesion Strength of Copper Nanowire Surface Fastener International conference

    KATO Motohiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>In recent years, connecting techniques using conductive nanomaterials imitating gecko's feet, for example, metal nanowires, carbon nanotubes and conductive polymer materials as a surface fastener have been reported. These connecting techniques utilize van der Waals force generated between the surfaces of nanomaterials. Recently, we have developed the copper nanowire surface fasteners (Cu NSF) as a conductive connector. Since copper has high electrical conductivity and is inexpensive, the Cu NSF can be expected to be practically used as a new surface mounting technique. Moreover, Cu NSF can be connected at room temperature utilizing van der Waals force, so that it is possible to avoid the damage to electronic parts during solder reflow process. However, the adhesion strength of current Cu NSF is still small as compared with traditional solders. The reason is considered that the contact areas of the nanowires were not sufficient because the nanowires collided and collapsed during connecting. In this research, we attempted to increase the contact area of nanowires for improving adhesion strength of Cu NSF. The adhesion strength of the Cu NSFs having nanowires with 100 nm and 400 nm diameter reached the largest value, and increasing with the increase of preload. This investigation showed that the contact areas of nanowires increased and mechanical entanglement of nanowires occurred because of increasing the preload of connecting.</p>

  163. Development of ZnO Thin Film Sensor Array for Minute Pressure Measurement International conference

    KAWAI Kota, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>Cancer is one of the three major causes of death in Japan. The 90% of patients with cancer dies from metastasis. Therefore, it is essential to do the cancer treatment properly, in which the metastasis should be prevented or the place should be predicted where the cancer cells are going to spread to. However, the mechanical mechanism of metastasis is still under research. We attempt to develop a pressure sensor array that can continuously measure the force of nN order generated by the cancer cells in a distributed manner. The requirements that a pressure sensor array need to meet are as follows: the pressure sensor array must adhere to the surface of a cancer cell via many points, besides, it could measure the magnitude of the force (nN). The zinc oxide (ZnO) thin film, as the piezoelectric material, offers a desirable approach to fulfilling the need for measurement of the mechanical field generated by the cancer cells. In our research, we fabricated a set of plural sensors (Size: 100 μm×100 μm, Thickness: 1 μm) on a substrate by using the methods of sputtering and photolithography. In other words, we developed a multi-point pressure sensor array. The main purpose of this study is to evaluate the sensitivity of the sensor, we used Au or Cr buffer layers, on which the ZnO thin film was formed, to find out the influence of the sensitivity of the sensor. Moreover, we measured the output voltage as a function of the load by using the sensor. In summary, the result of experiments shows that the sensitivity of the sensor is 5.31 mV/N.</p>

  164. Fabrication of Single Crystal Al Nanowire Array by Stress-induced Atomic Diffusion for Development of Transparent Conductive Film International conference

    TANAKA Yuki, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>In recent years, the development of a transparent conductive film using metal nanowires (NW) as a dispersing material has been carried out. Recent studies have reported many methods for fabricating transparent conductive films using Ag NW. However, Ag is a rare metal and there is a problem that the price is susceptible to market fluctuations. In order to utilize inexpensive Al NW as a new dispersing material, we developed a single crystal Al NW array fabrication method. The present method utilizes atomic diffusion to convert Al atoms to NW shape. Compressive stress and stress gradient in the Al thin film which is generated due to the difference in linear expansion coefficient between Al and Si when heating the Al / Si substrate. The atomic diffusion phenomenon caused by such stress is called stress migration (SM). It is a major feature of this method that NW generation is possible with two simple steps, film formation and heating. However, this method has a problem that the generation density of Al NW is low. In this research, we tried to increase the stress gradient by partial etching of Al film and introduce adhesion intermediate layer, and tried to improve generation density. As a result, we could get high density of Al NW with etching depth 10 nm and Cr film thickness 1.5 nm.</p>

  165. Nanoscroll Formation of Metal-coated Nanobelt with Residual Stress Induced in Coating Film International conference

    TOGAWA Yosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    <p>In recent years, various nanomaterials have been studied and a wide variety of applications have been attracted as the outcome of nanotechnology development. As research progresses, it can be expected that nanomachine technology will be a future subject. In this case a nanoscale power source is necessary, but it has not yet been put to practical use. Therefore, we propose a nanoscroll as a new nanoscale energy storage device. The advantage of nanoscroll is that they can storage energy with high efficiency and high density, and can be used as actuators by a simple procedure. We have built up a new material processing method for bending deformation of nanomaterials. In previous study, we succeeded in forming nanocoils by applying this method to nanowires. In this study, we tried to create nanoscroll by applying it to nanobelt. We achieved creating the shape with different curvatures at the tip and root of the nanobelt by nonuniformly sputtering in longitudinal direction. The deformation in the pitch direction was also suppressed.</p>

  166. Self-deformation of Coated Al Nanowires Induced by Residual Stress in Coating Film International conference

    UEDA Yuji, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of Mechanical Engineering Congress, Japan

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    <p>Micro/nano coils have been expected to be utilized in various applications as small inductors. Various methods have been proposed for fabricating them. Most of these methods were based on self-assembly technique such as thermal sublimation and chemical vapor deposition. In our previous study, we proposed an alternative method based on a mechanical process, where a straight nanowire is bent by depositing a thin film with a circumferentially nonuniform thickness on the nanowire. The bending is due to the misfit strain of the coated film. In order to enhance the bending, we also adopted a heat treatment that induces a creep flow only in the nanowire and thereby released the constraint of the nanowire on elastic bending due to film strain. However, the shape control of micro/nano coils such as coil pitch and direction of helical deformation was still not succeeded. In present study, we investigated the effects of film thickness and nanowire position on the coil formation during coil formation in the sputtering chamber. We achieved the shape control of micro/nano coils by varying the film thickness and nanowire position.</p>

  167. 薄膜残留応力を利用した被覆 Al ナノワイヤの自己変形 International conference

    上田 祐志, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 2016年度年次大会講演会  2016.9 

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    Venue:九州大学  

  168. Influence of ECM elasticity to dynamics field of ECM during stem cells differentiation International conference

    YAMAMOTO Ryosuke, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2018  The Japan Society of Mechanical Engineers

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  169. Measurement on mechanical dynamic field of ECM induced by the process of stem-cell differentiation with different ECM elasticities International conference

    MORITA Yasuyuki, YAMAMOTO Ryosuke, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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  170. Fabrication of Cu<sub>2</sub>O Nanowire Array by Thermal Oxidation and Reduction Process used for Solar Water Splitting International conference

    ZHANG Yiqi, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>It is well-known that traditional fossil energy sources such as oil are limited. Hydrogen is attracting the attention of the world because it is renewable, plentiful in supply, clean and non-toxic. Cu<sub>2</sub>O is a promising material for solar water splitting because it has an impressive performance as photocathode. It is a p-type semiconductor and with a band gap of 2.0 eV, which could theoretically deliver a solar to hydrogen conversion efficiency of 18% for water splitting. In this research, we use tube furnace to fabricate Cu<sub>2</sub>O nanowire (NW) by thermal oxidation and reduction process of thin copper plate. Different experimental conditions (temperature, time and gas flow rate) were investigated to find out the best parameters for nanowire synthesis (diameter, length, and number density of NW) which is better for the photoelectrochemical system.</p>

  171. 熱疲労を受けるナノワイヤ面ファスナーの接続強度および電気的特性の評価 International conference

    徳 悠葵, 野田 修二, 森田 康之, 巨 陽

    日本機械学会 第29回計算力学講演会 CMD2016  2016.9 

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    Venue:名古屋大学  

  172. Connection Strength and Electrical Property of Nanowire Surface Fastener during Heat Fatigue Test International conference

    TOKU Yuhki, NOTA Shuji, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of The Computational Mechanics Conference

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  173. Development of functional DDS carrier utilizing temperature-responsive polymer International conference

    KOBAYASHI Kodai, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2019  The Japan Society of Mechanical Engineers

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  174. Development of Controlled-Release DDS Carrier Applicated Temperature-Responsive Polymer International conference

    KOBAYASHI Kodai, MORITA Yasuyuki, WAKIMOTO Takuma, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Drug delivery system (DDS) is able to realize the treatment of cancer with lower side effects and higher efficiency comparing to conventional chemotherapy by controlling the in vivo dynamics of drugs. In recent years, there are many studies regarding to the release control of anticancer drug loaded in DDS in order to enhancing its performance. However, so far the reported controllable drug release DDSs require external stimulation such as light and cooling as triggers for drug release, which cannot reach the deep part inside the human body. To control the release in the deep part inside the human body, here, we aimed at to develop a new DDS carrier which can control drug release by applying magnetic field. Magnetic mesoporous silica (MMS) and ureido-containing poly (allylamine-co-allylurea) copolymers (PAU) were used in this study. PAU is a kind of polymer having upper critical temperature. By modifying it to the surface of magnetic mesoporous silica, it is possible to realize the control of drug release of the DDS carrier triggered by the core heat generation induced by an alternating magnetic field, thereby realizing the control of drug release in the deep part inside the human body. DDS carrier developed in this research enables highly efficient treatment that combines hyperthermia with core heat generation and drug treatment with drug release at the cancer in the body. To synthesize PAU modified MMS (MMS-PAU), magnetite was prepared by thermal decomposition method and MMSs were synthesized by a template method. PAU was prepared by reacting polyallylamine with potassium cyanate. Finally, PAU was grafted on the surface of MMS by introducing amide bonds. We confirmed that MMS-PAU has the drug release control ability and MMS-PAU is effective for cancer therapy.</p>

  175. Controlled drug release of Fe3O4@mSiO2 nanoparticles with phase transition behavior of thermosensitive polymer International conference

    WAKIMOTO Takuma, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2018  The Japan Society of Mechanical Engineers

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  176. Stress measurement of tumor-cell spheroid using oil-droplet mechanical sensor International conference

    UMEI Wataru, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering  2018  The Japan Society of Mechanical Engineers

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  177. Improving Adhesion Strength and Thermal Conductivity of Nanowire Surface Fastener International conference

    NONOMURA Riku, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>Solder has been used for the conventional bonding technology in electronic assembly for a long time. However, the traditional reflow soldering technique is characterized by high heating temperatures. Moreover, due to the progress of power devices, the working temperature in the electrical packages is increased. Therefore, we have proposed nanowire surface fastener (NSF) based on Cu nanowire arrays by which cold bonding for electrical packaging can be realized. Since copper is a high thermal conductive material, a satisfactory heat transfer characteristic is expected. In this paper, we investigated the improvements of the strength and thermal properties by changing the connecting load. The template method was used for fabricating Cu nanowire arrays, and the bonding strength of Cu NSF was evaluated by a tensile test. The highest bonding strength (205.06 N/cm<sup>2</sup>) was recorded when two nanowire arrays were connected by the connecting load of 125 N. Simultaneously, we measured the electrical resistance of Cu NSF by a four-terminal method. The electrical resistance showed the opposite behaviour to the bonding strength. Specifically, the larger connecting load we applied, the lower electrical resistance it showed. In metallic materials, since free electrons are carriers of the electric current and heat transfer, the electric conductivity and the thermal conductivity are closely related. Therefore, improvements of the electric and thermal conductivity are expected when electrical resistance decreases.</p>

  178. 機械的伸縮刺激を用いた間葉系幹細胞の腱細胞分化誘導に対する伸縮波形の影響 International conference

    丹羽 光司, 森田 康之, 徳 悠葵, 巨 陽

    生体医工学  2019  公益社団法人 日本生体医工学会

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    <p>幹細胞に伸縮刺激を与えると機能亢進が起こる. そのメカニズムは明らかにされていないが, 近年の研究で伸縮周波数が大きな影響を持つことが示唆されている. 本研究では腱細胞への分化に焦点をあて,遺伝子発現量を観察することで, 間葉系幹細胞の腱分化特性を評価する. 初めに,伸縮刺激を各細胞に一様に加えることを目的に細胞培養膜を作製し, 細胞の配向を制御した. その後, 周波数を0.1~10Hzと広域に設定し, 伸縮実験を行った.その結果,腱組織の生理環境に近い0.1および1Hzの領域で大きな遺伝子発現が見られた.</p>

  179. 機械的伸縮刺激による腱細胞分化に関する1細胞計測 International conference

    山下 貴大, 森田 康之, 徳 悠葵, 巨 陽

    日本機械学会東海支部第65期総会・講演会  2016.3.18 

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  180. Application of a temperature-responsive polymer to a core-shell nanocarrier for development of controlled-release DDS International conference

    KOBAYASHI Kodai, MORITA Yasuyuki, WAKIMOTO Takuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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  181. 同軸構造を有するマイクロ波原子間力顕微鏡プローブの作製および評価 International conference

    平林 貴大, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 2016年度年次大会講演会  2016.9 

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    Venue:九州大学  

  182. Fabrication and Evaluation of Microwave Atomic Force Microscope Probe Formed with Coaxial Structure International conference

    HIRABAYASHI Takahiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of Mechanical Engineering Congress, Japan

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    <p>With the development of nanotechnology in recent years, many researchers have focused on the fabrication of nanomaterials and nanostructures. To apply these nanomaterials and nanostructures into electronic devices, there are great needs of quantitative measurement of electrical properties of them. To satisfy these demands, we have developed the measurement instrument named microwave atomic force microscopy (M-AFM). Special probes with two unique abilities which are transmitting and radiating the microwaves were used for M-AFM. To improve these abilities, the tip of the probe was changed from slit structure to coaxial one. In this paper the new process of fabrication of coaxial structured probes were described, and the results of M-AFM measurement on the Au/GaAs sample using former slit probe and developed coaxial probe were presented. M-AFM measurement using coaxial probe obtained the clearer image of microwave responses. Results of measurements indicated coaxial probes have higher resolution in electrical properties measurement.</p>

  183. Influence of cyclic uniaxial stretching frequency on hMSC-to-tenocyte differentiation International conference

    HIRANO Yusho, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering  2017  The Japan Society of Mechanical Engineers

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  184. Influence of Material Surface on the Measurement of Local Electrical Conductivity using Microwave Atomic Force Microscopy International conference

    HATANO Takahiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016.10  The Proceedings of the Materials and Mechanics Conference

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    <p>With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures. To apply these nanomaterials and nanostructures into nanodevices, the measurement technology for measuring electrical properties at high spatial resolution has been requested. Therefore, our group has developed Microwave Atomic Force Microscopy (M-AFM) in order to assess electrical conductivity in a minute area. This paper describes influence of material surface on the measurement of local electrical conductivity using M-AFM. Results of this experiment indicate actually that M-AFM can measure electrical conductivity in a local area accurately without being affected by the material surface.</p>

  185. マイクロ波原子間力顕微鏡を用いた局所導電率測定に及ぼす試料表面形状の影響 International conference

    波多野 貴大, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 M&M2016材料力学カンファレンス  2016.10 

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    Venue:神戸大学  

  186. Local Permittivity Evaluation Based on the Force Variation of Microwave Atomic Force Microscopy International conference

    Bo TONG, Minji ZHAO, Yuhki TOKU, Yasuyuki MORITA, Yang JU

    The Proceedings of The Computational Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    Microwave atomic force microscopy (M-AFM) is designed to realize the non-contact measurement of topography and electrical property at nanoscale simultaneously. For the evaluation of dielectric materials, since the detected reflected signal depends strongly on the probe-sample distance, in non-contact mode the quantitative evaluation regardless of the effect of distance is difficult. In this study, the effect of microwave on the force between the probe and dielectric materials was investigated. A theoretic model based on the reflection of electromagnetic wave was established to describe the distance dependence of microwave intensity between sample and probe. The relationship between the force gradient and sample permittivity was obtained and the permittivity of Al<sub>2</sub>O<sub>3</sub>, Ge, and ZrO<sub>2</sub> was evaluated using this theoretical model.

  187. Volume FractionMeasurement of Carbon Fiber Reinforced Thermoplastic by Microwaves International conference

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of the Materials and Mechanics Conference

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    <p>Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof. CFRTP is used for structural members such as aircrafts, automobiles, blades of electricgenerating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in the guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reflection wave of the microwave. Using a theory model, the volume fraction was evaluated from the conductivity. As a result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.</p>

  188. マイクロ波を用いた熱可塑性炭素繊維強化プラスチックの繊維含有率測定技術の開発 International conference

    田所 昴, 巨 陽, 森田 康之, 徳 悠葵

    日本機械学会 M&M2016材料力学カンファレンス  2016.10 

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    Venue:神戸大学  

  189. Non-contactive measurement of strain in stainless steel by microwaves International conference

    ITO Atsushi, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2019  The Japan Society of Mechanical Engineers

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    <p>Stainless alloy is widely used in implants, dams and bridges because of its high corrosion resistance. However, these structures can be exposed to loads during their useful life and cause plastic deformation. Therefore, it is essential to know the plastic strain of the material in order to control the quality of the product. The conventional way to measure strain is the strain gauge method, but since physical contact is required at the time of gage attachment, a method to measure strain in non-contact fashion is required. Therefore, in this research, we focused on microwaves often used in nondestructive testing. Microwaves have less influence on the human body compared to X-ray. Unlike ultrasonic waves, microwaves do not require a transmission medium and can propagate in air favorably and at high speed. Therefore, we used microwaves to measure the electrical resistivity of plastically deformed test pieces. As a result, correlations were confirmed between the measured electrical resistivity and strain, and it was shown that the strain of stainless steel could be evaluated from the measured electrical resistivity.</p>

  190. マイクロ波を利用した熱可塑性炭素繊維強化プラスチックの繊維含有率の定量評価 International conference

    田所昴, 徳悠葵, 森田康之, 巨陽

    日本機械学会 M&M2015材料力学カンファレンス  2015.11.21 

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  191. Local Permittivity Measurement Utilizing Atomic Force between Probe and Sample Caused by Microwave International conference

    ZHAO Minji, TONG Bo, TOKU Yuki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of the Materials and Mechanics Conference

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    <p>With the development of nanotechnology, different types of scanning probe microscopy (SPM) have been developed to satisfy the requirement of nanotechnology. The microwave detection system is combined on the atomic force microscopy (AFM) to evaluate the electrical properties of the materials simultaneously. It is found that when microwave is applied through the probe, the microwave has interaction with the material. In this paper, the mechanism of the interaction between the microwave and material is investigated. We evaluated the probes by the microwave atomic force microscope (M-AFM) and verified our theoretical work. The result implies that the interatomic force between the tip and sample can be utilized to evaluate the permittivity of semiconductor and insulator materials.</p>

  192. マイクロ波が誘起する探針―試料間原子間力による局所誘電率評価 International conference

    チョウ ミンキ, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 M&M2016材料力学カンファレンス  2016.10 

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    Venue:神戸大学  

  193. マイクロビーズを利用したナノ多孔質膜の細孔密度の制御 International conference

    川島 大輝, 巨 陽, 森田 康之, 徳 悠葵

    日本機械学会東海学生会第47回学生員卒業研究発表講演会  2016.3.16 

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  194. Influence of Buffer Layers on the Piezoelectric Property of ZnO Film International conference

    KAWAI Kota, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    <p>Three-dimensional manipulation is necessary to make assembly operations during fabricating micro/nano-scale devices. However, it is difficult to release the objects at nanoscale due to the adhesion force between object and manipulator. Some researchers have developed manipulation devices which can reduce the adhesion force by utilizing the inertial force generated by vibrating the microcantilever with a bulk piezoelectric material placed near the base of it. However, there is still a problem of size, and it has not been applied to a narrow space such as a scanning electron microscope chamber. In order to further downsize the manipulator, simplification of the manipulation devices by using thin film piezoelectric materials instead of bulk piezoelectric ones and directly attaching to the microcantilever is effective. In this case, it is important to select the buffer layer which is originally used for relaxing the lattice mismatch to enhance the piezoelectricity of the thin film. In this study, the influence of buffer layer on piezoelectric properties of ZnO thin film was investigated. The deflection was measured when AC voltage was applied to the cantilever fabricated with ZnO thin film and the cross section of the cantilever were observed. As a result, using the Cr buffer layer rather than using Al buffer layer, the average of the cantilever tip displacement at each applied voltage was approximately 6 times larger and the piezoelectricity of the ZnO thin film was improved.</p>

  195. ナノワイヤ面ファスナーのための低細孔密度ポーラスアルミナテンプレートの開発 International conference

    宋 揚, 徳 悠葵, 森田 康之, 巨 陽

    日本機械学会 第24回機械材料・材料加工技術講演会(M&P2016)  2016.11 

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    Venue:早稲田大学  

  196. Rarefaction of Pore Density in Anodic Aluminum Oxide Nanoporous Membrane for the Fabrication of Nanowire Surface Fastener International conference

    SONG Yang, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016.11  The Proceedings of the Materials and processing conference

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  197. Improvement of Adhesive Strength of Nanowire Surface Fastener by the Optimization of Diameter Ratio of Nanowires International conference

    KATO Motohiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    <p>Lead-free solder has been used for surface mounting of electronic devices in consideration of the environment. However, there is a concern that the electronic parts may be damaged by heating during bonding because the lead-free solder has a high melting point. Therefore, development of a new bonding technique without heating is required. There are many studies on nanowires because of their unique characteristics which are different from bulk materials. In this paper, we fabricated Cu nanowire surface fasteners and investigated the improvement of strength by changing the diameter ratio of nanowires. Cr and Au films were formed as electrodes on glass substrates by sputtering. According to the template method, the polycarbonate template was fixed on one electrode to fabricate Cu nanowires by electrodepositing in the CuSO<sub>4</sub>·5H<sub>2</sub>O solution. After removing the template by etching with dichloromethane, the Cu nanowire surface fastener was fabricated. By applying a preload, the Cu nanowire surface fasteners were connected. Thereafter, the adhesion strength of the Cu nanowire surface fastener was evaluated by a tensile test. The highest bonding strength was found to be 162.6 N/cm<sup>2</sup> while the combination of the nanowire array with the diameter ratio of 1:4. Nanowires intertangling with each other was assumed to be an additional effect on the van der Waals force between nanowires.</p>

  198. Measurement of Intracellular Dynamic Field of a Stretched Cell Using Digital Image Correlation Mehtod International conference

    UMEI Wataru, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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  199. The Effect of Al Film Structure on the Growth of Al Nanowires Based on Stress Migration International conference

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2016  The Proceedings of the Materials and Mechanics Conference

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    <p>Nanowire (NW) is one-dimensional nanostructure with the diameter in nanoscale. Currently, we can fabricate NWs made from metal, metal oxide and semiconductor which could be utilized in various applications. In our previous study, we investigated a new fabrication method of Al NWs with high growth density by stress migration. It is generally known that Al is high conductivity and inexpensive material, therefore this method for mass production of Al NWs has a big advantage. However, the mechanism of fabrication has not been clear. In this study, we investigated the effect of surface roughness and etching depth induced by focused ion beam etching on the growth density of Al NWs. As a result, we found that etching depth strongly affects the growth density of Al NWs.</p>

  200. 金属被覆ナノワイヤの通電による形態変化の観察 International conference

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会  2013.11.8 

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  201. 金属被覆により生じるナノワイヤの曲げ変形に関する理論解析 International conference

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会  2014.7.19 

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  202. 製膜ひずみとコア流動を利用した金属被覆ナノワイヤの曲げ加工 International conference

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会  2010.10.9 

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  203. Electromagnetic Properties of Metal Coated-Micro/nano Coils Fabricated by Self-deformation

    UEDA Yuji, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>It is important to evaluate the magnetic property of magnetic storage devices which has very small size due to minitualization and high density. In this study, we propose a new scanning magnetic sensor combined by Atomic Force Microscopy (AFM) system and conductive nanocoil probe. Conductive nanocoil probe having an AFM tip combined with conductive micro/nano coil is possible to be used for magnetic evaluation according to the principle of electromagnetic induction. Furthermore, the conductive nanocoil probe has a distinctive feature which unites both observation and control of magnetic state at very small size, because the magnetic control is possible by the impressing current to the coil. To fabricate nanocoil on the AFM tip, the method of fabricating micro/nano coils which is based on a mechanical process, i.e., a straight nanowire is bent by depositing a thin film with a circumferentially nonuniform thickness on the nanowire, was used. The bending of nanowire is due to the misfit strain of the coated film. In order to enhance the bending, the heat treatment was conducted to induce a creep flow in the nanocoil, and to release the constraint of the nanowire on elastic bending due to film strain. From the result, the fabrication of nanocoil on the AFM tip with a high conductivity on the scale of 10<sup>6</sup> Ω・m was achieved successfully.</p>

  204. 振動慣性力を利用したナノワイヤの付着力制御 International conference

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会  2012.8.11 

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  205. 応力誘導法による三次元ナノ構造体の作製 International conference

    若林 信宏, 徳 悠葵, 巨 陽

    日本機械学会 2015年度年次大会  2015.9.13 

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  206. マイクロ 波原子間力顕微鏡の探針先端における原子間力の評価 International conference

    一二三 和馬, 徳 悠葵, 巨 陽

    日本機械学会 2015年度年次大会  2015.9.13 

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  207. ナノ加工プロセスによるナノワイヤ群のフック形成に関する研究 International conference

    徳 悠葵, 草間 美香, 巨 陽

    日本機械学会機械材料・材料加工部門 第23回機械材料・材料加工技術講演会  2015.11.13 

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  208. ナノワイヤの真性ひずみ誘起曲げ加工条件の実験的検討 International conference

    徳 悠葵, 村岡 幹夫

    精密工学会東北支部学術講演会  2009.11.28 

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  209. ストレスマイグレーションによる超高品質 Alナノワイヤの創製と電気的特性の評価 International conference

    柴田 貴俊, 小島 直樹, 徳 悠葵, 巨 陽

    日本機械学会 2015年度年次大会  2015.9.13 

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  210. コア流動法により作製した金属被覆マイクロコイルの発生磁場評価 International conference

    徳 悠葵, 村岡 幹夫

    一般社団法人日本機械学会  2013.9.8 

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  211. コアシェルナノ構造を利用した原子拡散によるナノウィスカー生成に関する研究 International conference

    徳 悠葵, 村岡 幹夫, 巨 陽

    日本機械学会 材料力学部門 若手シンポジウム2015  2015.8.10 

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  212. The shape control and performance evaluation of nanowire surface fastener

    Mika KUSAMA, Yuhki TOKU, Yang JU

    The international conference on advanced technology in experimental mechanics 2015 and the 14th Asian conference on experimental mechanics  2015.10.4 

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  213. T0301-1-4 Curvature Control of Nanocoils Produced by Viscous Flow of Core Material International conference

    TOKU Yuhki, MURAOKA Mikio

    The Japan Society of Mechanical Engineers  2010.9.4 

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    Various methods have been proposed for fabricating nanocoils in order to extend the range of elements for building nanodevices. Most of these methods are based on self-assembly technique. We have previously demonstrated an alternative method in which a straight nanowire is bent by depositing a thin film on the nanowire. The bending is due to the misfit strain of the coated film. However, nanocoil formation using this method is highly inefficient. In this study, we developed an advanced method in which the helical formation of coated nanowires takes place because of the viscous flow of the core material, i.e., the nanowires, and the misfit strain of the coating film. When the melting temperature of the nanowire material is lower than that of the coating, elevating the temperature induces a viscous flow, i.e., creep, which only occurs in the nanowire. The creep releases the constraint of the nanowire on elastic bending due to film strain.

  214. OS1507 Investigating Effect of Film Thickness on Bending Deformation of Metal-Coated Nanowires International conference

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and Mechanics Conference  2014  The Japan Society of Mechanical Engineers

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    In this study, we discussed about the effect of film thickness on bending deformation of coated nanowire (NW). The three dimensional theoretical model for analyzing the effect was proposed in this paper. The dependence of the misfit strain on the film thickness was introduced in the model. We concluded that bending direction of the NW varied with increasing the coating film thickness. This result arises from the dependence of the misfit strain on the film thickness and the nonuniform film thickness along the circumference of the NW.

  215. OS14-6 The Shape Control and Performance Evaluation of Nanowire Surface Fastener(Semiconductor Devices and Electronic Packaging 2,OS14 Electronic and photonic packages,APPLICATIONS)

    Kusama Mika, Toku Yuhki, Ju Yang

    The Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2015  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmeatem.2015.14.212

    CiNii Research

  216. OS14-6 The Shape Control and Performance Evaluation of Nanowire Surface Fastener(Semiconductor Devices and Electronic Packaging 2,OS14 Electronic and photonic packages,APPLICATIONS)

    Kusama Mika, Toku Yuhki, Ju Yang

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2015 

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  217. OS06-2-4 Manipulation of Nanowires by Chopsticks

    Kobayashi Kohtaro, Toku Yuhki, Muraoka Mikio

    Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2011 

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  218. OS0409-433 Quantitative Measurement of Volume Fraction of the Carbon Fiber Reinforced Thermoplastic by Microwaves International conference

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2015  The Proceedings of the Materials and Mechanics Conference

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    Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof CFRTP is used for structural members such as aircrafts, automobiles, blades of electric-generating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in quality control and a guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reply of the reflection wave of the microwave. And using a theory model, the volume fraction was evaluated from the conductivity. As the result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.

  219. OS0409-433 Quantitative Measurement of Volume Fraction of the Carbon Fiber Reinforced Thermoplastic by Microwaves International conference

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2015  The Proceedings of the Materials and Mechanics Conference

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    Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof CFRTP is used for structural members such as aircrafts, automobiles, blades of electric-generating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in quality control and a guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reply of the reflection wave of the microwave. And using a theory model, the volume fraction was evaluated from the conductivity. As the result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.

  220. Manipulation of Nanowires by Chopsticks

    Kohtaro KOBAYASHI, Yuhki TOKU, Mikio MURAOKA

    International Conference on Advanced Technology in Experimental Mechanics 2011  2011.9.19 

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  221. J2220204 Fabrication of Three Dimensional Nanostructures by Stress-induced Method International conference

    WAKABAYASHI Nobuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

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    In this study. we suggested simple and easy fabrication technique of flowe-like nanomaterials called Nano Flower (NF) by stress-induced method. From the observation of NFs grown on substrates which have different surface conditions, growth of NFs is probably related to residual stress of surface of substrates. EDS analysis results show that NFs grow up by taking in atmospheric carbon dioxide. NFs are expected as application to carbon dioxide capture and storage.

  222. J2220204 Fabrication of Three Dimensional Nanostructures by Stress-induced Method International conference

    WAKABAYASHI Nobuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

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    In this study. we suggested simple and easy fabrication technique of flowe-like nanomaterials called Nano Flower (NF) by stress-induced method. From the observation of NFs grown on substrates which have different surface conditions, growth of NFs is probably related to residual stress of surface of substrates. EDS analysis results show that NFs grow up by taking in atmospheric carbon dioxide. NFs are expected as application to carbon dioxide capture and storage.

  223. J0610105 Fabrication of Ultra-High Quality Al Nanowires Based on Stress-induced Method and Evaluation of Their Electrical Properties International conference

    SHIBATA Takatoshi, TOKU Yuhki, JU Yang, KOJIMA Naoki

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

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    We describe the result of the electrical conductivity measurement of single crystalline aluminum nanowires. These nanowires are fabricated by simply heating the Al samples in air. The growth mechanism is stress-induced migration. Four electrodes were patterned on nanowires by the photolithographic technique and we obtained the resistivity of nanowires by four-terminal measurement. The relationship between electrical conductivity and diameter was examined experimentally.

  224. J0610105 Fabrication of Ultra-High Quality Al Nanowires Based on Stress-induced Method and Evaluation of Their Electrical Properties International conference

    SHIBATA Takatoshi, TOKU Yuhki, JU Yang, KOJIMA Naoki

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

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    We describe the result of the electrical conductivity measurement of single crystalline aluminum nanowires. These nanowires are fabricated by simply heating the Al samples in air. The growth mechanism is stress-induced migration. Four electrodes were patterned on nanowires by the photolithographic technique and we obtained the resistivity of nanowires by four-terminal measurement. The relationship between electrical conductivity and diameter was examined experimentally.

  225. J0610104 Evaluation of Interatomic Force on the Tip of Probe by using Microwave Atomic Force Microscope International conference

    HIFUMI Kazuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

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    With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures such as nanowires. To apply these nanomaterials and nanostructures into nanodevices, there are great needs of the quantitative measurement of electrical properties of materials in an infinitesimal area. Recently, it has been reported that the microwave gives an effect to an interatomic force in local area among materials. Therefore, it is thought that an identification of materials and an evaluation of electrical characteristics become possible by clarifying the relation between microwave and interatomic force. Therefore, we investigated interatomic force under the tip of probe by focusing on the force-distance curve measurement using microwave atomic force microscopy (M-AFM) as the first step. This paper describes the method and the results of the force-distance curve measurement on the sample of Au, Si, and glass. Results of this experiment indicate actually that the effect of microwave is large in material which has high electric conductivity.

  226. J0610104 Evaluation of Interatomic Force on the Tip of Probe by using Microwave Atomic Force Microscope International conference

    HIFUMI Kazuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2015  The Japan Society of Mechanical Engineers

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    With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures such as nanowires. To apply these nanomaterials and nanostructures into nanodevices, there are great needs of the quantitative measurement of electrical properties of materials in an infinitesimal area. Recently, it has been reported that the microwave gives an effect to an interatomic force in local area among materials. Therefore, it is thought that an identification of materials and an evaluation of electrical characteristics become possible by clarifying the relation between microwave and interatomic force. Therefore, we investigated interatomic force under the tip of probe by focusing on the force-distance curve measurement using microwave atomic force microscopy (M-AFM) as the first step. This paper describes the method and the results of the force-distance curve measurement on the sample of Au, Si, and glass. Results of this experiment indicate actually that the effect of microwave is large in material which has high electric conductivity.

  227. GS0706-432 The Fabrication of High Density Single Crystal Al Nanowires by Stress Migration International conference

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2015  The Proceedings of the Materials and Mechanics Conference

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    Nanowires have been expected to be utilized in various applications. Recently, many researchers have reported about single crystal or polycrystalline nanowires where the single crystal nanowires are shown to have a higher conductivity compared to the polycrystalline ones. In our previous study, we investigated the fabrication process of single crystal nanowires by stress migration. However, because the mechanism of fabrication was not clear, the generation density of single crystal nanowires was low for this method. In this study, we suggested a new method to increase the generation density of single crystal nanowires. An etching process was added to the previous fabrication method and the conditions of the substrate surface were changed. By doing this, the stress generated around the concentrated Al atoms was larger than the threshold stress needed to fabricate the nanowires. As a result of the added etching process, we achieved a nanowire generation density 100 times that of the conventional fabrication method.

  228. GS0706-432 The Fabrication of High Density Single Crystal Al Nanowires by Stress Migration International conference

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Japan Society of Mechanical Engineers  2015  The Proceedings of the Materials and Mechanics Conference

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    Nanowires have been expected to be utilized in various applications. Recently, many researchers have reported about single crystal or polycrystalline nanowires where the single crystal nanowires are shown to have a higher conductivity compared to the polycrystalline ones. In our previous study, we investigated the fabrication process of single crystal nanowires by stress migration. However, because the mechanism of fabrication was not clear, the generation density of single crystal nanowires was low for this method. In this study, we suggested a new method to increase the generation density of single crystal nanowires. An etching process was added to the previous fabrication method and the conditions of the substrate surface were changed. By doing this, the stress generated around the concentrated Al atoms was larger than the threshold stress needed to fabricate the nanowires. As a result of the added etching process, we achieved a nanowire generation density 100 times that of the conventional fabrication method.

  229. Fabrication of tiny whiskers on core-shell nanowires based on stress-induced atomic migration

    Yuhki TOKU, Mikio MURAOKA, Yang JU

    International multi-conference on engineering and technology innovation 2015  2015.10.30 

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    Venue:Kaohsiung, Taiwan  

  230. F041003 Development of Functional Nanowire Surface Fastener International conference

    JU Yang, TOKU Yuhki

    The Japan Society of Mechanical Engineers  2015  The Proceedings of Mechanical Engineering Congress, Japan

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    Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we introduce a new patterned structure of nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized. The mechanical bonding enables normal and shear bonding strengths of more than 5 N/cm^2. Simultaneously, the parasitic resistance of a pair of surface fasteners is only approximately 2Ω. The present technique can be performed at room temperature, thereby improving the process compatibility and reliability of SMDs. Surface fasteners based on high melting point metallic nanowires are temperature-resistant for many critical applications. In addition, bonding without solder material is positive for the recycling of rare metals in SMDs.

  231. F041003 Development of Functional Nanowire Surface Fastener International conference

    JU Yang, TOKU Yuhki

    The Japan Society of Mechanical Engineers  2015  The Proceedings of Mechanical Engineering Congress, Japan

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    Mass production of surface mount devices (SMDs) relies heavily on reflow soldering and has become the cornerstone of today's electronic industry. However, the traditional reflow soldering technique is characterized by high heating temperatures, toxic solder materials and low recycling rate of SMDs. Here, we introduce a new patterned structure of nanowire arrays named a surface fastener through which cold bonding for surface mount technology can be realized. The mechanical bonding enables normal and shear bonding strengths of more than 5 N/cm^2. Simultaneously, the parasitic resistance of a pair of surface fasteners is only approximately 2Ω. The present technique can be performed at room temperature, thereby improving the process compatibility and reliability of SMDs. Surface fasteners based on high melting point metallic nanowires are temperature-resistant for many critical applications. In addition, bonding without solder material is positive for the recycling of rare metals in SMDs.

  232. Enhanced Bending of Coated Nanowires Using Viscous Flow of Core Material: Production of Nanoinductance

    Yuhki TOKU, Mikio MURAOKA

    12th International Conference on Electronics Materials and Packaging  2010.10.25 

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  233. Effect of Film Thickness on Helical Formation of Coated Nanowires in an Enhanced-Bending Technique

    Yuhki TOKU, Mikio MURAOKA

    JSME/ASME 2011 International conference on materials & processing  2011.6.13 

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  234. 722 Fabrication of Hook Nanowire Surface by Mechanical Bending International conference

    TOKU Yuhki, KUSAMA Mika, JU Yang

    The Proceedings of the Materials and processing conference  2015  The Japan Society of Mechanical Engineers

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  235. 722 Fabrication of Hook Nanowire Surface by Mechanical Bending International conference

    TOKU Yuhki, KUSAMA Mika, JU Yang

    The Proceedings of the Materials and processing conference  2015  The Japan Society of Mechanical Engineers

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  236. 511 Observation of Topological Change of Metal-Coated Nanowire under Current Supply International conference

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of the Materials and processing conference  2013  The Japan Society of Mechanical Engineers

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  237. 330 Helical Formation of Metal-Coated Nanowires by Core Reduction to Release Residual Stress International conference

    TOKU Yuhki, MURAOKA Mikio

    The Japan Society of Mechanical Engineers  2012.11.30 

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  238. 211 Theoretical Analysis for Helical Formation of Coated Nanowire by Viscous Flow of Core Material International conference

    KUDO Ryusuke, TOKU Yuhki, MURAOKA Mikio

    The Japan Society of Mechanical Engineers  2013.9.20 

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  239. 104 Herical Formation of Metal-Coated Nanowires by Viscous Flow of the Core Material International conference

    TOKU Yuki, MURAOKA Mikio

    The Japan Society of Mechanical Engineers  2010.3.12 

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  240. 002 Bend Processing of Metal-Coated Nanowires by Viscous Flow of Core Material and Intrinsic Strain of Coating Film International conference

    TOKU Yuhki, MURAOKA Mikio

    The Japan Society of Mechanical Engineers  2010.10.9 

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    Various methods have been proposed for fabricating nanocoils in order to extend the range of elements for building nanodevices. Most of these methods are based on self-assembly technique. We have previously demonstrated an alternative method in which a straight nanowire is bent by depositing a thin film on the nanowire. The bending is due to the misfit strain of the coated film. However, nanocoil formation using this method is highly inefficient. In this study, we developed an advanced method in which the helical formation of coated nanowires takes place because of the viscous flow of the core material, i.e., the nanowires, and the misfit strain of the coating film. When the melting temperature of the nanowire material is lower than that of the coating, elevating the temperature induces a viscous flow, i.e., creep, which only occurs in the nanowire. The creep releases the constraint of the nanowire on elastic bending due to film strain.

  241. Development of a system for fabricating metallic micro/nanowire materials by electromigration

    ITO Yuta, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2020  The Japan Society of Mechanical Engineers

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  242. Effect of high-frequency and high-density current on adhesive strength of copper thin film

    YASUDA Kazuhiro, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2020  The Japan Society of Mechanical Engineers

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  243. Evaluation of Electric Current-Induced Improvement of Fracture Characteristics in SUS316

    Yoon Sungmin, Kimura Yasuhiro, Cui Yi, Toku Yuhki, Ju Yang

    MATERIALS TRANSACTIONS  2021  公益社団法人 日本金属学会

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    <p>The application of high-density pulsed electric current (HDPEC) is one of the effective methods for the modification of material properties in metals. To evaluate fracture behavior modified by HDPEC, critical fracture parameters such as fracture strength, fracture toughness, and fracture profile of crack tip are important criteria. This work investigates the finite element analysis (FEA) based evaluation of improved fracture characteristics by the application of HDPEC in a SUS 316 austenite stainless steel. Tensile tests were first conducted to deduce the modified material properties with different conditions of HDPEC. A series of theoretical considerations was employed to estimate the modified fracture toughness. The relationship between critical fracture strength and critical crack length was numerically determined based on the estimated fracture toughness. The results in FEA showed that critical von Mises stress on the singularity at the crack tip increases as the effect of HDPEC increases. The evolution of increased fracture toughness with respect to conditions of HDPEC was specified. Crack opening profiles were simulated to assist the explanation. The evaluation of fracture parameters in this study proposes that the modified material properties by HDPEC play a positive role to resist crack propagation.</p>

  244. Evaluation of Electric Current-Induced Improvement of Fracture Characteristics in SUS316

    Yoon Sungmin, Kimura Yasuhiro, Cui Yi, Toku Yuhki, Ju Yang

    MATERIALS TRANSACTIONS  2021  公益社団法人 日本金属学会

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    <p>The application of high-density pulsed electric current (HDPEC) is one of the effective methods for the modification of material properties in metals. To evaluate fracture behavior modified by HDPEC, critical fracture parameters such as fracture strength, fracture toughness, and fracture profile of crack tip are important criteria. This work investigates the finite element analysis (FEA) based evaluation of improved fracture characteristics by the application of HDPEC in a SUS 316 austenite stainless steel. Tensile tests were first conducted to deduce the modified material properties with different conditions of HDPEC. A series of theoretical considerations was employed to estimate the modified fracture toughness. The relationship between critical fracture strength and critical crack length was numerically determined based on the estimated fracture toughness. The results in FEA showed that critical von Mises stress on the singularity at the crack tip increases as the effect of HDPEC increases. The evolution of increased fracture toughness with respect to conditions of HDPEC was specified. Crack opening profiles were simulated to assist the explanation. The evaluation of fracture parameters in this study proposes that the modified material properties by HDPEC play a positive role to resist crack propagation.</p>

  245. Assessment of creep behavior using a damage-coupled model for martensitic stainless steel

    YOON Sungmin, KIMURA Yasuhiro, TOKU Yuhki, JU Yang, PARK Soojeong, KIM Yunhae

    Mechanical Engineering Journal  2021  一般社団法人 日本機械学会

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    <p>In this study, the Liu–Murakami (LM) creep damage-coupled model was considered to evaluate the creep properties of martensitic stainless steel. The degree of creep damage was examined at two temperatures (565 ℃ and 593 ℃) to assess mechanically and thermally activated processes. A series of high applied stresses (applied stress/ultimate strength > 0.5) was considered for accelerated creep loadings. A full set of creep constants was determined by combining the Norton and LM models. Constitutive equations were used to quantitatively estimate experimental creep curves. The variation in creep constants was discussed based on stress sensitivity, such as stress triaxiality and applied stress, depending on the power of stress. The creep strain–time curves were successfully estimated. The comparison between the experimental and analytical results was in good agreement in the tertiary regime. In addition, the compensation of the two applied temperatures provides a supplementary explanation of the relationship between the ultimate strength and rupture time in terms of temperature sensitivity. The analytical results show that different applied stresses and temperatures could be compensated to characterize the creep behavior of the material. Thus, the creep strain–time and creep strain rate–certain rupture time curves were finally achieved. The analytical process in this study provides a laboratory-scale assessment of creep properties using the accelerated creep test and LM model.</p>

  246. Improvement of Mechanical Properties of Titanium alloy by High-Density Pulsed Electric Current

    IWASE Rui, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Titanium alloys have been widely used in versatile productions due to their excellent mechanical properties. Conversely, the effective technique for the improvement of mechanical properties is required. Although heat treatment is used to enhance the mechanical properties, it increases processing cost. Recently, high-density pulsed electric current (HDPEC) has been studied for repairing defects and damages in metallic materials. Therefore, it would be expected to improve mechanical properties of Titanium alloy by applying HDPEC instead of heat treatment. This work studied the effect of HDPEC on the mechanical properties of Titanium alloy Ti-6Al-4V. Tensile test was conducted after applying HDPEC to the material. The application of HDPEC contributes to improve the elongation and tensile strength of 10% and 3.2% compared to unapplied ones, respectively. In addition, Vickers hardness was decreased with increasing current density. The change in the microstructure of the material before and after applying HDPEC was observed based on the X-ray diffraction analysis: The rate of <i>β</i>-phase in the material was increased by applying HDPEC. As a result, the mechanical properties of titanium alloy were improved by applying HDPEC due to the phase transformation.</p>

    DOI: 10.1299/jsmemm.2019.os0326

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  247. Influence of Buffer Layers on the Piezoelectric Property of ZnO Film

    KAWAI Kota, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    <p>Three-dimensional manipulation is necessary to make assembly operations during fabricating micro/nano-scale devices. However, it is difficult to release the objects at nanoscale due to the adhesion force between object and manipulator. Some researchers have developed manipulation devices which can reduce the adhesion force by utilizing the inertial force generated by vibrating the microcantilever with a bulk piezoelectric material placed near the base of it. However, there is still a problem of size, and it has not been applied to a narrow space such as a scanning electron microscope chamber. In order to further downsize the manipulator, simplification of the manipulation devices by using thin film piezoelectric materials instead of bulk piezoelectric ones and directly attaching to the microcantilever is effective. In this case, it is important to select the buffer layer which is originally used for relaxing the lattice mismatch to enhance the piezoelectricity of the thin film. In this study, the influence of buffer layer on piezoelectric properties of ZnO thin film was investigated. The deflection was measured when AC voltage was applied to the cantilever fabricated with ZnO thin film and the cross section of the cantilever were observed. As a result, using the Cr buffer layer rather than using Al buffer layer, the average of the cantilever tip displacement at each applied voltage was approximately 6 times larger and the piezoelectricity of the ZnO thin film was improved.</p>

    DOI: 10.1299/jsmemecj.2017.j2220205

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  248. Local Permittivity Measurement Utilizing Atomic Force between Probe and Sample Caused by Microwave

    ZHAO Minji, TONG Bo, TOKU Yuki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    <p>With the development of nanotechnology, different types of scanning probe microscopy (SPM) have been developed to satisfy the requirement of nanotechnology. The microwave detection system is combined on the atomic force microscopy (AFM) to evaluate the electrical properties of the materials simultaneously. It is found that when microwave is applied through the probe, the microwave has interaction with the material. In this paper, the mechanism of the interaction between the microwave and material is investigated. We evaluated the probes by the microwave atomic force microscope (M-AFM) and verified our theoretical work. The result implies that the interatomic force between the tip and sample can be utilized to evaluate the permittivity of semiconductor and insulator materials.</p>

    DOI: 10.1299/jsmemm.2016.gs-34

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  249. Non-contactive measurement of strain in stainless steel by microwaves

    ITO Atsushi, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2019  The Japan Society of Mechanical Engineers

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    <p>Stainless alloy is widely used in implants, dams and bridges because of its high corrosion resistance. However, these structures can be exposed to loads during their useful life and cause plastic deformation. Therefore, it is essential to know the plastic strain of the material in order to control the quality of the product. The conventional way to measure strain is the strain gauge method, but since physical contact is required at the time of gage attachment, a method to measure strain in non-contact fashion is required. Therefore, in this research, we focused on microwaves often used in nondestructive testing. Microwaves have less influence on the human body compared to X-ray. Unlike ultrasonic waves, microwaves do not require a transmission medium and can propagate in air favorably and at high speed. Therefore, we used microwaves to measure the electrical resistivity of plastically deformed test pieces. As a result, correlations were confirmed between the measured electrical resistivity and strain, and it was shown that the strain of stainless steel could be evaluated from the measured electrical resistivity.</p>

    DOI: 10.1299/jsmemecj.2019.j40136p

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  250. Volume FractionMeasurement of Carbon Fiber Reinforced Thermoplastic by Microwaves

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    <p>Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof. CFRTP is used for structural members such as aircrafts, automobiles, blades of electricgenerating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in the guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reflection wave of the microwave. Using a theory model, the volume fraction was evaluated from the conductivity. As a result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.</p>

    DOI: 10.1299/jsmemm.2016.os04-07

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  251. Influence of Material Surface on the Measurement of Local Electrical Conductivity using Microwave Atomic Force Microscopy

    HATANO Takahiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    <p>With the development of nanotechnology in recent years, many researchers have focused on the development of nanomaterials and nanostructures. To apply these nanomaterials and nanostructures into nanodevices, the measurement technology for measuring electrical properties at high spatial resolution has been requested. Therefore, our group has developed Microwave Atomic Force Microscopy (M-AFM) in order to assess electrical conductivity in a minute area. This paper describes influence of material surface on the measurement of local electrical conductivity using M-AFM. Results of this experiment indicate actually that M-AFM can measure electrical conductivity in a local area accurately without being affected by the material surface.</p>

    DOI: 10.1299/jsmemm.2016.gs-33

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  252. Influence of cyclic uniaxial stretching frequency on hMSC-to-tenocyte differentiation

    HIRANO Yusho, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering  2017  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebiofro.2017.28.1a24

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  253. Fabrication and Evaluation of Microwave Atomic Force Microscope Probe Formed with Coaxial Structure

    HIRABAYASHI Takahiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2016  The Japan Society of Mechanical Engineers

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    <p>With the development of nanotechnology in recent years, many researchers have focused on the fabrication of nanomaterials and nanostructures. To apply these nanomaterials and nanostructures into electronic devices, there are great needs of quantitative measurement of electrical properties of them. To satisfy these demands, we have developed the measurement instrument named microwave atomic force microscopy (M-AFM). Special probes with two unique abilities which are transmitting and radiating the microwaves were used for M-AFM. To improve these abilities, the tip of the probe was changed from slit structure to coaxial one. In this paper the new process of fabrication of coaxial structured probes were described, and the results of M-AFM measurement on the Au/GaAs sample using former slit probe and developed coaxial probe were presented. M-AFM measurement using coaxial probe obtained the clearer image of microwave responses. Results of measurements indicated coaxial probes have higher resolution in electrical properties measurement.</p>

    DOI: 10.1299/jsmemecj.2016.j0120104

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  254. Application of a temperature-responsive polymer to a core-shell nanocarrier for development of controlled-release DDS

    KOBAYASHI Kodai, MORITA Yasuyuki, WAKIMOTO Takuma, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2018.j0220304

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  255. 機械的伸縮刺激を用いた間葉系幹細胞の腱細胞分化誘導に対する伸縮波形の影響

    丹羽 光司, 森田 康之, 徳 悠葵, 巨 陽

    生体医工学  2019  公益社団法人 日本生体医工学会

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    <p>幹細胞に伸縮刺激を与えると機能亢進が起こる. そのメカニズムは明らかにされていないが, 近年の研究で伸縮周波数が大きな影響を持つことが示唆されている. 本研究では腱細胞への分化に焦点をあて,遺伝子発現量を観察することで, 間葉系幹細胞の腱分化特性を評価する. 初めに,伸縮刺激を各細胞に一様に加えることを目的に細胞培養膜を作製し, 細胞の配向を制御した. その後, 周波数を0.1~10Hzと広域に設定し, 伸縮実験を行った.その結果,腱組織の生理環境に近い0.1および1Hzの領域で大きな遺伝子発現が見られた.</p>

    DOI: 10.11239/jsmbe.annual57.s25_1

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  256. Improving Adhesion Strength and Thermal Conductivity of Nanowire Surface Fastener

    NONOMURA Riku, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>Solder has been used for the conventional bonding technology in electronic assembly for a long time. However, the traditional reflow soldering technique is characterized by high heating temperatures. Moreover, due to the progress of power devices, the working temperature in the electrical packages is increased. Therefore, we have proposed nanowire surface fastener (NSF) based on Cu nanowire arrays by which cold bonding for electrical packaging can be realized. Since copper is a high thermal conductive material, a satisfactory heat transfer characteristic is expected. In this paper, we investigated the improvements of the strength and thermal properties by changing the connecting load. The template method was used for fabricating Cu nanowire arrays, and the bonding strength of Cu NSF was evaluated by a tensile test. The highest bonding strength (205.06 N/cm<sup>2</sup>) was recorded when two nanowire arrays were connected by the connecting load of 125 N. Simultaneously, we measured the electrical resistance of Cu NSF by a four-terminal method. The electrical resistance showed the opposite behaviour to the bonding strength. Specifically, the larger connecting load we applied, the lower electrical resistance it showed. In metallic materials, since free electrons are carriers of the electric current and heat transfer, the electric conductivity and the thermal conductivity are closely related. Therefore, improvements of the electric and thermal conductivity are expected when electrical resistance decreases.</p>

    DOI: 10.1299/jsmemm.2017.os1407

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  257. Stress measurement of tumor-cell spheroid using oil-droplet mechanical sensor

    UMEI Wataru, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebiofro.2018.29.1b16

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  258. Controlled drug release of Fe3O4@mSiO2 nanoparticles with phase transition behavior of thermosensitive polymer

    WAKIMOTO Takuma, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2018.30.1h16

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  259. Development of Controlled-Release DDS Carrier Applicated Temperature-Responsive Polymer

    KOBAYASHI Kodai, MORITA Yasuyuki, WAKIMOTO Takuma, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Drug delivery system (DDS) is able to realize the treatment of cancer with lower side effects and higher efficiency comparing to conventional chemotherapy by controlling the in vivo dynamics of drugs. In recent years, there are many studies regarding to the release control of anticancer drug loaded in DDS in order to enhancing its performance. However, so far the reported controllable drug release DDSs require external stimulation such as light and cooling as triggers for drug release, which cannot reach the deep part inside the human body. To control the release in the deep part inside the human body, here, we aimed at to develop a new DDS carrier which can control drug release by applying magnetic field. Magnetic mesoporous silica (MMS) and ureido-containing poly (allylamine-co-allylurea) copolymers (PAU) were used in this study. PAU is a kind of polymer having upper critical temperature. By modifying it to the surface of magnetic mesoporous silica, it is possible to realize the control of drug release of the DDS carrier triggered by the core heat generation induced by an alternating magnetic field, thereby realizing the control of drug release in the deep part inside the human body. DDS carrier developed in this research enables highly efficient treatment that combines hyperthermia with core heat generation and drug treatment with drug release at the cancer in the body. To synthesize PAU modified MMS (MMS-PAU), magnetite was prepared by thermal decomposition method and MMSs were synthesized by a template method. PAU was prepared by reacting polyallylamine with potassium cyanate. Finally, PAU was grafted on the surface of MMS by introducing amide bonds. We confirmed that MMS-PAU has the drug release control ability and MMS-PAU is effective for cancer therapy.</p>

    DOI: 10.1299/jsmemm.2019.gs25

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  260. Development of functional DDS carrier utilizing temperature-responsive polymer

    KOBAYASHI Kodai, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2019  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2019.32.2d23

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  261. Fabrication of Cu<sub>2</sub>O Nanowire Array by Thermal Oxidation and Reduction Process used for Solar Water Splitting

    ZHANG Yiqi, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>It is well-known that traditional fossil energy sources such as oil are limited. Hydrogen is attracting the attention of the world because it is renewable, plentiful in supply, clean and non-toxic. Cu<sub>2</sub>O is a promising material for solar water splitting because it has an impressive performance as photocathode. It is a p-type semiconductor and with a band gap of 2.0 eV, which could theoretically deliver a solar to hydrogen conversion efficiency of 18% for water splitting. In this research, we use tube furnace to fabricate Cu<sub>2</sub>O nanowire (NW) by thermal oxidation and reduction process of thin copper plate. Different experimental conditions (temperature, time and gas flow rate) were investigated to find out the best parameters for nanowire synthesis (diameter, length, and number density of NW) which is better for the photoelectrochemical system.</p>

    DOI: 10.1299/jsmemm.2018.gs0302

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  262. Measurement on mechanical dynamic field of ECM induced by the process of stem-cell differentiation with different ECM elasticities

    MORITA Yasuyuki, YAMAMOTO Ryosuke, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2018.j0270101

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  263. Influence of ECM elasticity to dynamics field of ECM during stem cells differentiation

    YAMAMOTO Ryosuke, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2018.30.1a18

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  264. Electromagnetic Properties of Metal Coated-Micro/nano Coils Fabricated by Self-deformation

    UEDA Yuji, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>It is important to evaluate the magnetic property of magnetic storage devices which has very small size due to minitualization and high density. In this study, we propose a new scanning magnetic sensor combined by Atomic Force Microscopy (AFM) system and conductive nanocoil probe. Conductive nanocoil probe having an AFM tip combined with conductive micro/nano coil is possible to be used for magnetic evaluation according to the principle of electromagnetic induction. Furthermore, the conductive nanocoil probe has a distinctive feature which unites both observation and control of magnetic state at very small size, because the magnetic control is possible by the impressing current to the coil. To fabricate nanocoil on the AFM tip, the method of fabricating micro/nano coils which is based on a mechanical process, i.e., a straight nanowire is bent by depositing a thin film with a circumferentially nonuniform thickness on the nanowire, was used. The bending of nanowire is due to the misfit strain of the coated film. In order to enhance the bending, the heat treatment was conducted to induce a creep flow in the nanocoil, and to release the constraint of the nanowire on elastic bending due to film strain. From the result, the fabrication of nanocoil on the AFM tip with a high conductivity on the scale of 10<sup>6</sup> Ω・m was achieved successfully.</p>

    DOI: 10.1299/jsmemm.2017.os1521

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  265. Self-deformation of Coated Al Nanowires Induced by Residual Stress in Coating Film

    UEDA Yuji, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2016  The Japan Society of Mechanical Engineers

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    <p>Micro/nano coils have been expected to be utilized in various applications as small inductors. Various methods have been proposed for fabricating them. Most of these methods were based on self-assembly technique such as thermal sublimation and chemical vapor deposition. In our previous study, we proposed an alternative method based on a mechanical process, where a straight nanowire is bent by depositing a thin film with a circumferentially nonuniform thickness on the nanowire. The bending is due to the misfit strain of the coated film. In order to enhance the bending, we also adopted a heat treatment that induces a creep flow only in the nanowire and thereby released the constraint of the nanowire on elastic bending due to film strain. However, the shape control of micro/nano coils such as coil pitch and direction of helical deformation was still not succeeded. In present study, we investigated the effects of film thickness and nanowire position on the coil formation during coil formation in the sputtering chamber. We achieved the shape control of micro/nano coils by varying the film thickness and nanowire position.</p>

    DOI: 10.1299/jsmemecj.2016.j2240104

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  266. Nanoscroll Formation of Metal-coated Nanobelt with Residual Stress Induced in Coating Film

    TOGAWA Yosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    <p>In recent years, various nanomaterials have been studied and a wide variety of applications have been attracted as the outcome of nanotechnology development. As research progresses, it can be expected that nanomachine technology will be a future subject. In this case a nanoscale power source is necessary, but it has not yet been put to practical use. Therefore, we propose a nanoscroll as a new nanoscale energy storage device. The advantage of nanoscroll is that they can storage energy with high efficiency and high density, and can be used as actuators by a simple procedure. We have built up a new material processing method for bending deformation of nanomaterials. In previous study, we succeeded in forming nanocoils by applying this method to nanowires. In this study, we tried to create nanoscroll by applying it to nanobelt. We achieved creating the shape with different curvatures at the tip and root of the nanobelt by nonuniformly sputtering in longitudinal direction. The deformation in the pitch direction was also suppressed.</p>

    DOI: 10.1299/jsmemecj.2017.j2220204

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  267. Fabrication of Single Crystal Al Nanowire Array by Stress-induced Atomic Diffusion for Development of Transparent Conductive Film

    TANAKA Yuki, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>In recent years, the development of a transparent conductive film using metal nanowires (NW) as a dispersing material has been carried out. Recent studies have reported many methods for fabricating transparent conductive films using Ag NW. However, Ag is a rare metal and there is a problem that the price is susceptible to market fluctuations. In order to utilize inexpensive Al NW as a new dispersing material, we developed a single crystal Al NW array fabrication method. The present method utilizes atomic diffusion to convert Al atoms to NW shape. Compressive stress and stress gradient in the Al thin film which is generated due to the difference in linear expansion coefficient between Al and Si when heating the Al / Si substrate. The atomic diffusion phenomenon caused by such stress is called stress migration (SM). It is a major feature of this method that NW generation is possible with two simple steps, film formation and heating. However, this method has a problem that the generation density of Al NW is low. In this research, we tried to increase the stress gradient by partial etching of Al film and introduce adhesion intermediate layer, and tried to improve generation density. As a result, we could get high density of Al NW with etching depth 10 nm and Cr film thickness 1.5 nm.</p>

    DOI: 10.1299/jsmemm.2018.gs0301

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  268. Development of ZnO Thin Film Sensor Array for Minute Pressure Measurement

    KAWAI Kota, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>Cancer is one of the three major causes of death in Japan. The 90% of patients with cancer dies from metastasis. Therefore, it is essential to do the cancer treatment properly, in which the metastasis should be prevented or the place should be predicted where the cancer cells are going to spread to. However, the mechanical mechanism of metastasis is still under research. We attempt to develop a pressure sensor array that can continuously measure the force of nN order generated by the cancer cells in a distributed manner. The requirements that a pressure sensor array need to meet are as follows: the pressure sensor array must adhere to the surface of a cancer cell via many points, besides, it could measure the magnitude of the force (nN). The zinc oxide (ZnO) thin film, as the piezoelectric material, offers a desirable approach to fulfilling the need for measurement of the mechanical field generated by the cancer cells. In our research, we fabricated a set of plural sensors (Size: 100 μm×100 μm, Thickness: 1 μm) on a substrate by using the methods of sputtering and photolithography. In other words, we developed a multi-point pressure sensor array. The main purpose of this study is to evaluate the sensitivity of the sensor, we used Au or Cr buffer layers, on which the ZnO thin film was formed, to find out the influence of the sensitivity of the sensor. Moreover, we measured the output voltage as a function of the load by using the sensor. In summary, the result of experiments shows that the sensitivity of the sensor is 5.31 mV/N.</p>

    DOI: 10.1299/jsmemm.2018.gs0204

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  269. Optimization of Effective Parameters for Improving Adhesion Strength of Copper Nanowire Surface Fastener

    KATO Motohiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>In recent years, connecting techniques using conductive nanomaterials imitating gecko's feet, for example, metal nanowires, carbon nanotubes and conductive polymer materials as a surface fastener have been reported. These connecting techniques utilize van der Waals force generated between the surfaces of nanomaterials. Recently, we have developed the copper nanowire surface fasteners (Cu NSF) as a conductive connector. Since copper has high electrical conductivity and is inexpensive, the Cu NSF can be expected to be practically used as a new surface mounting technique. Moreover, Cu NSF can be connected at room temperature utilizing van der Waals force, so that it is possible to avoid the damage to electronic parts during solder reflow process. However, the adhesion strength of current Cu NSF is still small as compared with traditional solders. The reason is considered that the contact areas of the nanowires were not sufficient because the nanowires collided and collapsed during connecting. In this research, we attempted to increase the contact area of nanowires for improving adhesion strength of Cu NSF. The adhesion strength of the Cu NSFs having nanowires with 100 nm and 400 nm diameter reached the largest value, and increasing with the increase of preload. This investigation showed that the contact areas of nanowires increased and mechanical entanglement of nanowires occurred because of increasing the preload of connecting.</p>

    DOI: 10.1299/jsmemm.2018.os1306

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  270. Strain dependence of MSCs under cyclic stretch stimulus to form tendon tissue

    HIGASHIURA Kouji, MORITA Yasuyuki, SATO Toshihiro, TOKU Yuhki, JU Yang

    The Proceedings of the JSME Conference on Frontiers in Bioengineering  2016  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebiofro.2016.27.b215

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  271. Improvement of mechanical properties of stainless steel alloy based on the electroplastic effect

    IWASE Rui, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2018.j0450402

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  272. Effect of high-frequency and high-density current on adhesive strength of copper thin film

    YASUDA Kazuhiro, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2020  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2020.j04209

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  273. Increase in Adhesion Strength of Au Thin Film via High-frequency and High-density Electric Current

    KIZAWA Kurama, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>In recent years, electronic devices have remarkably achieved miniaturization and high performance with the development of MEMS. In addition, the current density in the interconnect has risen due to the increase of electric energy accompanying the development of power devices. The delamination of thin film due to thermal stress and electromigration has become a problem. One method to improve the adhesion strength of thin film on a substrate is using an adhesion layer such as Cr or Ti between the thin film and the substrate. However, this method has the disadvantages that additional materials are required and the thickness of the interconnect increases. The adhesion strength of the thin film needs to be improved itself. This study proposed a method to apply high-density current with high frequency to thin film to improve the adhesion strength of it. The Au thin film (Size: 5 mm×45 mm×150 nm) was deposited on a glass substrate by radio frequency sputtering. Then, high-density current with high frequency was applied in thin film and the adhesion strength was measured by using peel test. As a result, the adhesion strength was improved by 20% or greater by applying high-density current with high frequency. Therefore, this method is expected to be a new strength improvement method for thin film.</p>

    DOI: 10.1299/jsmemm.2019.os1409

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  274. Improvement of Adhesive Strength of Nanowire Surface Fastener by the Optimization of Diameter Ratio of Nanowires

    KATO Motohiro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    <p>Lead-free solder has been used for surface mounting of electronic devices in consideration of the environment. However, there is a concern that the electronic parts may be damaged by heating during bonding because the lead-free solder has a high melting point. Therefore, development of a new bonding technique without heating is required. There are many studies on nanowires because of their unique characteristics which are different from bulk materials. In this paper, we fabricated Cu nanowire surface fasteners and investigated the improvement of strength by changing the diameter ratio of nanowires. Cr and Au films were formed as electrodes on glass substrates by sputtering. According to the template method, the polycarbonate template was fixed on one electrode to fabricate Cu nanowires by electrodepositing in the CuSO<sub>4</sub>·5H<sub>2</sub>O solution. After removing the template by etching with dichloromethane, the Cu nanowire surface fastener was fabricated. By applying a preload, the Cu nanowire surface fasteners were connected. Thereafter, the adhesion strength of the Cu nanowire surface fastener was evaluated by a tensile test. The highest bonding strength was found to be 162.6 N/cm<sup>2</sup> while the combination of the nanowire array with the diameter ratio of 1:4. Nanowires intertangling with each other was assumed to be an additional effect on the van der Waals force between nanowires.</p>

    DOI: 10.1299/jsmemecj.2017.j0330303

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  275. Mechanical Effects of CAFs on the Invasion Field of a Cancer Cell via Extracellular

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2019  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2019.32.1f14

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  276. Three-Dimensional Measurement of the Mechanical Fields and Fiber Structure around Cancer Cells Co-Cultured with CAFs

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Invasion of cells plays a major role in metastasis. Cancer cells interact with cancer-associated fibroblasts (CAFs) present in the tumor microenvironment and as a result enhance their invasive ability. However, the overall mechanism of the interaction has not been clarified. When cancer cells moving, they constantly exert power on the surrounding extracellular matrix (ECM). In addition, the material properties of the ECM are not uniform because the fiber structure constantly changes. Therefore, measuring the mechanical field around cancer cells is significant in revealing the interaction between cancer cells and CAFs. In this study, we analyze what kind of change is caused in the mechanical field of ECM around a cancer cell by the effects of CAFs under three dimensional culture. We cultured the pancreatic ductal carcinoma cells, SUIT-2 with the orthotopic CAFs in collagen gel. Three-dimensional images were acquired by a confocal microscope. Embedding the fluorescent beads in the gel at the same time, the beads adhere to the collagen and form a pattern, therefore it is possible to track the displacement field by using the digital volume correlation (DVC) method. At the same time, the collagen fiber density and orientation were evaluated based on 3D images. As a result, accumulation and arrangement of collagen fibers were observed in the direction of CAF protrusion, and it became clear that cancer cells under the influence of CAFs generate a dynamic field in a wider range.</p>

    DOI: 10.1299/jsmemm.2019.os0509

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  277. Fabrication of Photoelectrode Based on Cu<sub>2</sub>O/Cu Core-Shell Nanowires Array Used for Solar Water Splitting

    KASAHARA Ryutaro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>In recent days, hydrogen is considered as an alternative energy which could instead of the fossil fuel in the future. A new clean method to manufacture hydrogen gas is called solar water splitting. Cu<sub>2</sub>O is considered as a promising and attractive material for solar driven hydrogen production because the suitable band gap (ca. 2.0 eV) and the low cost. Based on the band gap, it can be calculated the maximum theoretical light-to-hydrogen conversion efficiency is 18% at AM 1.5 spectrum, and the theoretical photocurrent of 14.7 mA/cm<sup>2</sup>. However, the experimental conversion efficiency was much lower than the theoretical one, due to self-corrosion coinciding with water-splitting reaction and that an electron and a hole activated by the sun light irradiation are easily recombined in oxidation film. In this research, Cu<sub>2</sub>O/Cu core-shell Nanowire (NW) has been fabricated on the surface of the photoelectrode by the polycarbonate template method to increase the conversion efficiency by optimizing the NW structure. We have investigated the relationship between NW's structure and photocurrent density, as well as incident photo to current efficiency (IPCE). As a result, we find the optimum conditions of NW's diameter and oxidation time. The visible light responsiveness from IPCE results has also been confirmed.</p>

    DOI: 10.1299/jsmemm.2017.gs0301

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  278. Influence of the Cu<sub>2</sub>O/Cu Core-Shell Nanowires Density on Conversion Efficiency

    MATSUO Ryosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    <p>Currently, solar cells aremainlymade fromSi.However, due to the high cost and the limited resources of Si, new materials for solar cells are still needed. It has been proved that Cu<sub>2</sub>O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu<sub>2</sub>O solar battery is much lower than theoretical value. In this research, Cu<sub>2</sub>O/Cu core-shell NWs are fabricated on the surface of the solar cell by the AAO template method to increase light receiving area. As a result, we succeed in fabricating Cu<sub>2</sub>O/Cu core-shell NWs. The surface area of the solar cell is increased to about 151 times, which improve the solar energy conversion efficiency. And, we also find that the density of NWarrays effects the solar energy conversion efficiency.</p>

    DOI: 10.1299/jsmemm.2016.gs-40

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  279. Enhancement of Solar-to-hydrogen Conversion Efficiency in Water Splitting by Optimizing Morphology of Cu<sub>2</sub>O Nanostructure and Surface Modification

    IZUMI Yuri, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>Recently, Cu<sub>2</sub>O has been considered as an attractive material for solar water splitting due to its excellent characteristics such as small bandgap, visible light adsorption, abundance, and nontoxicity. The theoretical solar-to-hydrogen conversion efficiency (STH) of Cu<sub>2</sub>O is 18% for water splitting. To date, the value experimentally obtained by previous works has not attained and overcomed above ideal value, because of the lack of Cu<sub>2</sub>O in photocathode to absorb sunlight efficiently, the short diffusion length of minority cariers, and the Cu<sub>2</sub>O photocorrosion during water splitting. 3D nanostructures for water splitting and surface modification contribute to resolving these issues. Nanostructures can improve STH owing to high surface-to-volume ratio and short diffusion length for carrier transport compared with bulk materials. In addition, surface modification enables to promote the separation of photogenerated electron-hole pair and to protect the photoelectrode against photocorrosion, and thus resulting in the enhancement of stability in Cu<sub>2</sub>O photocathode. The present study aimed to improve STH and stability in Cu<sub>2</sub>O photocathode for water splitting by optimizing morphology of Cu<sub>2</sub>O nanostructures and surface modification. In order to determine the suitable conditions for water splitting, the relationship between the morphology of the structure and STH was examined. The photocathode with Cu<sub>2</sub>O nanostructures exhibited maximum photocurrent density of 4.58 mA/cm<sup>2</sup> at a potential of 0 V vs. reversible hydrogen electrode (RHE) and STH of 5.63%. Besides, surface modification was successfully introduced by covering nanostructures with homogeneous and conformal layers formed by atomic layer deposition (ALD).</p>

    DOI: 10.1299/jsmemm.2019.gs11

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  280. Development of Cu2O 3D nanostructure used for photo electrode of solar water splitting

    IZUMI Yuri, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2018.j2220104

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  281. Development of a Neutron Spin Filter for a T Violation Search in Compound Nuclei

    T. Yamamoto, H. M. Shimizu, M. Kitaguchi, K. Hirota, T. Okudaira, C. C. Haddock, N. Oi, I. Ito, S. Endo, S. Takada, J. Koga, T. Yoshioka, T. Ino, K. Asahi, T. Momose, T. Iwata, K. Sakai, T. Oku, A. Kimura, M. Hino, T. Shima, Y. Yamagata

    Proceedings of the International Conference on Neutron Optics (NOP2017)  2018.11.28  Journal of the Physical Society of Japan

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    DOI: 10.7566/jpscp.22.011018

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  282. DVC Measurement on the Deformation Field of ECM Surrounding a Tumor Spheroid During the Invasive Progression

    Morita Yasuyuki, Nakano Yusuke, Oshima Kanau, Toku Yuhki, Ju Yang

    The Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2019  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmeatem.2019.1009d1000

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  283. Measurement on dynamic invasive field induced by multi-tumor spheroids using DVC method

    NAKANO Yusuke, MORITA Yasuyuki, YAMAUCHI Takashi, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2017  The Japan Society of Mechanical Engineers

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    <p>When tumor cells metastasize, invasion of cells plays a major role. In particular, invasion of epithelial tumor cells is induced by performing epithelial-mesenchymal transition (EMT). EMT is a process that have high motility induced by external factors in which epithelial cells are transformed into mesenchymal cells. It is a very important process in invasion. The tumor cells generate forces during cell invasion through a three-dimensional (3D) matrix. Measuring the mechanics field generated in the Extracellular Matrix (ECM) surrounding the cells is an important way to understand the behavior of tumor cells in 3D environment. Therefore, in this study, spheroids, which are the source of the invasion for tumor cells, were embedded in a collagen gel, and the deformations of the collagen gel surrounding the spheroids were measured. Using the DVC method, the matrix deformations around spheroids were measured by tracking the 3D positions of fluorescent beads embedded in the collagen gel. In addition, we added TGF-β1 which facilitates the invasion of tumor cells, and the influence of TGF-β1 on the mechanical property of spheroids was quantitatively evaluated. As a result, it was found that the maximum displacement of spheroids treated with TGF-β1 is larger than that of the one's without TGF-β1 treatment.</p>

    DOI: 10.1299/jsmemm.2017.os0113

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  284. Development of active targeting DDS using Fe<sub>3</sub>O<sub>4</sub>@mSiO<sub>2</sub>-tLyP-1 nanoparticles

    MORITA Yasuyuki, SAKURAI Ryohei, WAKIMOTO Takuma, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2017  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2017.29.2b35

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  285. Measurement of Angular Distributions in 139La\((\text{n},\gamma )\) Reaction for T Violation Search

    T. Okudaira, H. M. Shimizu, M. Kitaguchi, K. Hirota, C. C. Haddock, N. Oi, I. Ito, T. Yamamoto, S. Endo, S. Takada, J. Koga, T. Yoshioka, T. Ino, K. Asahi, T. Momose, T. Iwata, K. Sakai, T. Oku, A. Kimura, M. Hino, T. Shima, Y. Yamagata

    Proceedings of the International Conference on Neutron Optics (NOP2017)  2018.11.28  Journal of the Physical Society of Japan

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    DOI: 10.7566/jpscp.22.011041

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  286. OS0409-433 Quantitative Measurement of Volume Fraction of the Carbon Fiber Reinforced Thermoplastic by Microwaves

    TADOKORO Subaru, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2015  The Japan Society of Mechanical Engineers

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    Carbon fiber reinforced thermoplastic (CFRTP) has high specific strength, rigidity and corrosion proof CFRTP is used for structural members such as aircrafts, automobiles, blades of electric-generating windmills and sporting goods. Because the mechanical strength of CFRTP depends on the volume fraction, the evaluation of the volume fraction of CFRTP is very important in quality control and a guarantee of quality. Thus, the nondestructive inspection method to detect the volume fraction in CFRTP is required. In this paper, we measured the conductivity of CFRTP from the reply of the reflection wave of the microwave. And using a theory model, the volume fraction was evaluated from the conductivity. As the result, the potential of microwave inspection to evaluate the volume fraction in CFRTP was presented.

    DOI: 10.1299/jsmemm.2015._os0409-43

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  287. OS06-2-4 Manipulation of Nanowires by Chopsticks

    Kobayashi Kohtaro, Toku Yuhki, Muraoka Mikio

    The Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics  2011  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmeatem.2011.10._os06-2-4-

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  288. Control of Shape and Density of SnO<sub>2</sub> Nanobelt

    TOGAWA Yosuke, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>In recent years, various nanostructure materials such as nanowires, nanorods and nanobelts have been studied widely due to their excellent properties. Especially, much attention was paid by researchers in the preparation of oxide nanostructure materials due to their good optical and electrical properties. Numerous oxide nanostructure materials were synthesized so far, among which SnO<sub>2</sub> is considered to be an important one, because it is a typical n-type semiconductor. Particularly, SnO<sub>2</sub> nanobelts exhibited extensive optoelectronic and gas-sensitive properties which make them being excellent candidates for a wide range of applications such as gas sensors and transparent conductive film. SnO<sub>2</sub> nanobelt is generally synthesized by thermal evaporation method, but it is difficult to control the shape, size and density of SnO<sub>2</sub> nanobelts in the thermal evaporation process. However, since the elastic modulus and conductivity of the nanobelt depend on its shape and size, it is important to control shape and size of nanobelt. Hence, in this study, we adjusted experimental parameters such as pressure during heating and concentrations of gold nanoparticle solution to control the shape and size of nanobelts. From the scanning electron microscope image, we found that the aspect ratio of cross-section was controlled by pressure during heating. The results show that we succeeded in controlling the aspect ratio of cross-section and density of the SnO<sub>2</sub> nanobelts. From the above, it is expected that the improvement of flexibility and transparency of a transparent conductive film could be realized.</p>

    DOI: 10.1299/jsmemm.2018.gs0205

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  289. Measurement of 4D dynamics field in ECM surrounding tumor cells effected by epithelialmesenchymal transition using digital volume correlation method

    YAMAUCHI Takashi, MORITA Yasuyuki, TOKU Yuhki, JU Yang, KAWASE Naoki

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2017  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2017.29.1f42

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  290. Experimental study on the stress state of 3D ECM at the start of invasion of cancer spheroids

    NAKANO Yusuke, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2018  The Japan Society of Mechanical Engineers

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    <p>When tumor cells metastasize, invasion of cells plays a major role. The tumor cells initiate invasion by generating force and changing the physical structure of the extracellular matrix (ECM) surrounding the tumor. However, the detail process of changing the structure of the ECM has not been elucidated. At this time, measuring the mechanics field generated in the ECM is an important way to understand behavior of tumor cells in 3D. Therefore, in this study, spheroids, which are the source of the invasion as a tumor cells, were embedded in a collagen gel, and the deformations of the collagen gel surrounding the spheroids were measured. Using the DVC method, the matrix deformations around spheroids were measured by tracking the 3D positions of fluorescent beads embedded in the collagen gel. To photograph the initial state of the ECM, we added tritonX-100 to the spheroid at the end of the experiment and photographed the state of no stress from the spheroid. In addition, we calculated the divergence of the deformations field and discussed on density change of ECM. As a result, it was found that spheroids systematically generate the deformation field and change the density of ECM. It was suggested that invasion occurs in the low density part.</p>

    DOI: 10.1299/jsmemm.2018.os0610

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  291. Experimental study on influence of ECM elasticity on invasive behavior of tumor cells

    USHIDA Masato, MORITA Yasuyuki, OSHIMA Kanau, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2019  The Japan Society of Mechanical Engineers

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    <p>Cancer cells are known to lead human death, but they are difficult to treat. The reason is that the mechanism of metastasis has not been elucidated. Since cancer cells are known to induce the hardening and moving surrounding tissues i.e. extracellular matrix (ECM), this study aimed to increase the elastic modulus of ECM without changing the density of collagen fibers. The crosslinking agent (EDCNHS) was used for this purpose. By making collagen gel with administering the crosslinking agent, it was succeeded to increase the elastic modulus of ECM up to 5 times approximately than the case without crosslinking agent. Based on this result, it is possible to observe the infiltration behavior of cancer cells with the difference of elastic modulus under three-dimensional culture by enclosing cancer cells in the collagen gel.</p>

    DOI: 10.1299/jsmemecj.2019.j02303

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  292. The effect of cancer assisted fibroblasts on mechanical field of cancer invasion

    OSHIMA Kanau, MORITA Yasuyuki, OHUCHIDA Kenoki, TOKU Yuhki, JU Yang

    The Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME  2019  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmebio.2019.31.2f22

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  293. Development of a system for fabricating metallic micro/nanowire materials by electromigration

    ITO Yuta, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2020  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2020.j22312

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  294. Improving spinnability of carbon nanotube sheet by controlling the density and alignment of carbon nanotube array

    TAGUCHI Takuto, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2018  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2018.j2220103

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  295. Development of Flexible Transparent Conductive Film with Carbon Nanotube Sheet

    TAGUCHI Takuto, KIMURA Yasuhiro, TOKU Yuhki, JU Yan

    The Proceedings of the Materials and Mechanics Conference  2019  The Japan Society of Mechanical Engineers

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    <p>In Recent years, the demand of transparent conductive films (TCFs) has been increased widely due to the potential application for electronic devices, such as touch panels, liquid crystal displays, and transparent electrodes. With the development of flexible devices, TCFs are required to be flexible. However, indium tin oxide (ITO), the most widespread material used for TCFs, is brittle ceramic material and expensive. Therefore, instead of ITO, TCF materials have to be flexible and low cost. Multiwalled carbon nanotubes (CNT) sheet has been studied as a replacement for ITO owing to its flexibility and low cost. However, the sheet resistance of CNT sheet is still higher than that of ITO: the values of 1000to 1500 Ω/□. One of the reasons is the contact resistance of each other of CNTs in a CNT sheet. In this study, metal nanoparticles were coated on the CNT sheet to reduce the contact resistance. After being coated with Cu/Ni, the contact resistance was modified and the sheet resistance was reduced to 300 Ω/□ or less, while the transmittance at the wave length of 550 nm maintains 80 % or higher. The results provide that CNT sheet is a promising candidate for flexible TCF material, realizing more effective production at lower cost than ITO.</p>

    DOI: 10.1299/jsmemm.2019.gs24

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  296. Experimental Investigating Strength Improvement of Carbon Nanotube Composite Materials

    KASAHARA Ryutaro, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2016  The Japan Society of Mechanical Engineers

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    <p>Carbon nanotube (CNT) composite materials are expected to be utilized in the field of aerospace and automobile industry due to their excellent mechanical property and relatively light weight. However, the experimental material strength measured from tensile test was much lower than the theoretical one calculated by simulation. In order to clarify the mechanism how CNT in the resin improves the material strength and increase experimental value, tensile tests and observation of fracture surface have been conducted in this research. Flaked composite material specimens with different local CNT content rates were prepared for tensile test. As a result of tensile test, we got material strength of flacked composite material specimens, which was approximately 2.5 times higher than that of only resin. By microscopic observation, we confirmed CNT pulled out from base material on fracture surface. In this research, we achieved that a higher local content rate of CNT leads to a higher experimental strength.</p>

    DOI: 10.1299/jsmemecj.2016.j2210207

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  297. The Effect of Al Film Structure on the Growth of Al Nanowires Based on Stress Migration

    SUZUKI Takamasa, TOKU Yuhki, MORITA Yasuyuki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2016  The Japan Society of Mechanical Engineers

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    <p>Nanowire (NW) is one-dimensional nanostructure with the diameter in nanoscale. Currently, we can fabricate NWs made from metal, metal oxide and semiconductor which could be utilized in various applications. In our previous study, we investigated a new fabrication method of Al NWs with high growth density by stress migration. It is generally known that Al is high conductivity and inexpensive material, therefore this method for mass production of Al NWs has a big advantage. However, the mechanism of fabrication has not been clear. In this study, we investigated the effect of surface roughness and etching depth induced by focused ion beam etching on the growth density of Al NWs. As a result, we found that etching depth strongly affects the growth density of Al NWs.</p>

    DOI: 10.1299/jsmemm.2016.gs-39

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  298. Fabrication of Nanowire Surface Fastener by Template Method

    TOKU Yuhki, JU Yang

    JOURNAL OF JAPANESE SOCIETY OF TRIBOLOGISTS  2021.10.15  Japanese Society of Tribologists

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    <p>Surface-mount techniques primarily depend on soldering. However, soldering techniques have encountered some challenges in recent years. The reflow process in electronic assembly needs high-temperature processes, which result in undesired thermal damages and residual stress at a bonding interface. Therefore, there is an urgent requirement to attach electronic parts to circuit boards with good mechanical and electrical properties at room temperature. We recently developed a metallic nanowire surface fastener (NSF) to resolve the abovementioned problems. This fastener can connect electronic components on a substrate at room temperature using the van der Waals force between each nanowire. In this paper, we introduce a preparing method of a high-density nanowire array constituting the NSF. The NSF fabricated through the simple template method showed the room temperature bonding ability. The NSF’s adhesion strength and electrical properties were investigated by adjusting the nanowire parameters, such as diameter, length, density (number per area), preload, and shape. We also introduce some NSF applications, such as 64-pin NSF that behaves like a ball grid array for application to actual electronic devices and the fabrication of an NSF on a flexible substrate.</p>

    DOI: 10.18914/tribologist.66.10_756

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  299. Measurement of Intracellular Dynamic Field of a Stretched Cell Using Digital Image Correlation Mehtod

    UMEI Wataru, MORITA Yasuyuki, TOKU Yuhki, JU Yang

    The Proceedings of Mechanical Engineering Congress, Japan  2017  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemecj.2017.j0250205

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  300. Improve the adhesion strength of thin film by high frequency current

    PENG Yanhong, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2021  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemm.2021.os1106

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  301. Effects of Crystal Orientation of Al Thin Film and Underlayer Materials on Stress-induced Nanowire Growth

    YAMADA Hideyuki, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2021  The Japan Society of Mechanical Engineers

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    DOI: 10.1299/jsmemm.2021.gs12

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  302. J212014 Evaluation for Magnetic Field of Metal-Coated Microcoils Formed by Viscous Flow of Core Material

    TOKU Yuhki, MURAOKA Mikio

    The Proceedings of Mechanical Engineering Congress, Japan  2013  The Japan Society of Mechanical Engineers

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    We have proposed a method on helical formation of coated nanowire, which utilized the misfit strain of the film coated on the nanowire. We also adopted a heat treatment that induces a creep flow only in the nanowire and thereby released the constraint of the nanowire on elastic bending due to film strain. In this study, we evaluate the magnetic field of Pt-coated CuO microcoils formed by using the method. A direct current is supplied to the coil on Au electrodes, and the voltage of the coil is measured using four-point probe method. The coil is melted due to a possible reason of joule heating at a current of 700 μA. The measured voltage increases proportionally to the increasing current until the current is 580 μA. Then, the voltage irregularly increases until the electrical discontinuity. We predict that the density of magnetic flux of the coil is 1.2 G at the current of 580 μA. This magnetic field is 3〜4 times of the geomagnetism.

    DOI: 10.1299/jsmemecj.2013._j212014-1

    CiNii Research

  303. Study on improvement of drug loading of core-shell type DDS nanocarrier

    SUMIDA Hiroki, KIMURA Yasuhiro, TOKU Yuhki, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2021  The Japan Society of Mechanical Engineers

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    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemm.2021.gs14

    CiNii Research

  304. Cold welding performance of curved metal nanowires

    CUI Yi, TOKU Yuhki, KIMURA Yasuhiro, JU Yang

    The Proceedings of the Materials and Mechanics Conference  2021  The Japan Society of Mechanical Engineers

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    Language:Japanese   Presentation type:Oral presentation (general)  

    DOI: 10.1299/jsmemm.2021.os1111

    CiNii Research

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Research Project for Joint Research, Competitive Funding, etc. 6

  1. 周期的電子風力を利用した原子再配列法の開拓

    Grant number:20352230  2021.4 - 2027.3

    創発的研究支援事業 

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    Authorship:Principal investigator  Grant type:Competitive

  2. 薄膜残留応力を利用した金属被覆ナノワイヤの芯付ナノコイル形成とその応用

    2016.4 - 2017.3

    池谷科学技術振興財団 単年度研究助成 

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    Grant type:Competitive

  3. コアシェルナノ構造を利用した応力誘導による超微細ナノウィスカーの創製に関する研究

    2016.4 - 2017.3

    豊田理研スカラー  

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    Grant type:Competitive

  4. 不均一被覆の残留膜ひずみを利用したナノベルトのゼンマイ形成

    2015.10 - 2016.9

    大澤科学技術振興財団による研究助成 

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    Grant type:Competitive

  5. 不均一製膜による偏心膜ひずみを利用した金属被覆ナノベルトのゼンマイ形成に関する研究

    2015.4 - 2016.3

    日本板硝子材料工学助成会研究助成 

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    Grant type:Competitive

  6. コア流動法を利用したナノワイヤ巻付け加工に関する研究

    2015.4 - 2016.3

    東京工業大学基金による研究助成 

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    Grant type:Competitive

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KAKENHI (Grants-in-Aid for Scientific Research) 9

  1. 周期的電子風力を利用した原子再配列法の開拓

    2021.4 - 2028.3

    国立研究開発法人科学技術振興機構  創発的研究支援事業 

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    Authorship:Principal investigator 

  2. Nanoscale Structure Control of Metallic Material Through Electrical Wind Force and Mechanism Clarification

    Grant number:20K20531  2020.7 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Challenging Research (Pioneering)

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    Authorship:Coinvestigator(s) 

  3. 多層金属ナノ構造を利用した応力誘導原子拡散による極小単結晶ナノウィスカーの創製

    Grant number:20K20959  2020.7 - 2022.3

    日本学術振興会  科学研究費助成事業  挑戦的研究(萌芽)

    徳 悠葵, 木村 康裕

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    Authorship:Principal investigator 

    Grant amount:\6370000 ( Direct Cost: \4900000 、 Indirect Cost:\1470000 )

    本研究では,独自のコアシェル型ナノチューブの作製手法を利用し,極小の単結晶銅ナノウィスカーを創製する.極小ナノウィスカーは粒子状と異なり,高アスペクト比かつ大きな結晶露出面積を持つ新たなCO2分解触媒として期待できる.ウィスカーの創製原理は,外皮金属により密閉した空間に加熱還元された金属が析出する際,線膨張係数の差により還元金属中に圧縮応力が生ずる.このとき還元金属の原子拡散が誘起され,外皮の格子欠陥・結晶粒界を拡散した還元金属原子がウィスカー状に析出する.応力による原子拡散により創製したナノウィスカーはほぼ単結晶であり,副反応の少ないCO2の分解触媒へと応用できる.
    近年の環境・エネルギー問題を解決する手段として,人工光合成が注目されており,二酸化炭素(CO2)の分解触媒として銅のナノ粒子が研究されている.しかしながら現状では,分解時のエネルギー収支(得られるエネルギーに対する分解促進に必要なエネルギーの割合)が悪く,実用的な人工光合成に至っていない.エネルギー収支の改善を行うためには,触媒作用に有効な結晶面を特定し,露出面積を増やすといった対策が有効と考えられる.しかし,ナノスケールの材料を自由な形状で創製・取り扱うことは容易でなく,多くの研究報告では最も単純な粒子状材料に限定されているのが現状である.
    そこで本研究では,独自のコアシェル型ナノチューブの作製手法を利用し,極小の単結晶銅ナノウィスカーの創製を目的とする.極小ナノウィスカーは粒子状とは異なり,高アスペクト比かつ大きな結晶露出面積を持つ新たなCO2分解触媒として期待できる.初年度に得られた成果は以下の通りである.
    1.コアシェル型ナノチューブの膜厚検討:カーボンの膜厚・外皮の膜厚・鋳型材料である酸化銅ナノワイヤの直径など,各種パラメータを選定し,コアシェル型ナノチューブの作成に成功した.また,基板上に分散した酸化銅ナノワイヤをもとに,同時に複数のコアシェル型ナノチューブを作成することに成功した.
    2.最適還元条件の確立:カーボン膜を利用した加熱還元過程に対し周囲環境の及ぼす影響を調査するため,真空中・大気中・不活性ガス中などの条件にて加熱還元を実施した.これにより,上述のコアシェル型ナノチューブの作成に成功した.一方,当初予定していたチューブ表面からのナノウィスカーの析出には再現性に検討の余地が残った.
    当初想定していた以上に複数のコアシェル型ナノチューブを同時に作成することに成功し,目標であるナノウィスカー創製の大量成長を見込めるようになった.一方,ナノウィスカー創製の再現性には課題が残り,コアシェル構造の寸法や還元条件にさらなる検討の余地が必要となった.総合的に概ね順調に進展している.
    最終年度は,初年度に課題となったナノウィスカー創製の再現性向上のため,再度1.コアシェル型ナノチューブの膜厚検討および2.還元条件の確立に加えて,つぎの通り研究を推進する.
    3.ナノウィスカーの結晶面制御:外皮金属および膜厚の選定により,ナノウィスカーの結晶面制御を行う.周方向不均一な外皮の製膜を行う場合,薄膜の不整合ひずみによって出発材料の酸化銅ナノワイヤには曲げ変形が生じる.一方,曲率を有する面から析出するナノウィスカーはその成長位置の格子欠陥の大きさなどに依存した形状,寸法により成長するものと考えられる.また,結晶面の表面エネルギーに依存した優先成長結晶面が存在すると考えられる.以上の点を踏まえ,ナノウィスカーの結晶面制御について調査する.
    4.ナノウィスカーによるCO2分解:作製したナノウィスカーを用い,密閉空間に充填したCO2の分解実験を行う.また,ナノウィスカー表面に現れている結晶方位を特定し,分解に寄与する銅の結晶面を検証する.

  4. 高周波高密度電流が原子配列に与える「揺さぶり」を利用した自己原子再配列技術の創出

    Grant number:20H02025  2020.4 - 2023.3

    日本学術振興会  科学研究費助成事業  基盤研究(B)

    徳 悠葵, 巨 陽

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    Authorship:Principal investigator 

    Grant amount:\17940000 ( Direct Cost: \13800000 、 Indirect Cost:\4140000 )

    本研究では,金属薄膜を対象に,熱処理に依らない高周波高密度電流による原子の再配列を世界で初めて実現する.これは,電子と原子の力学的相互作用,すなわち電子風力を原子配列の「揺さぶり」として利用することにより,自発的に原子を安定位置へと再配列させる極めて独創的な手法である.これにより,結晶方位の整列,結晶粒の増大,最密結晶面の増加,点・線欠陥の消滅を誘起し,薄膜の応用上重要な密着性・導電性といった機械特性・電気特性の向上を実現する.さらに,高周波高密度電流がなす原子の駆動現象のメカニズムを解明し,熱処理に依らない新たな電子風力を基盤とした原子配列・結晶構造の制御法として学理構築を目指す.
    本研究では金属薄膜を対象に,高周波の高密度電流が原子配列に及ぼす電子風力の周期的「揺さぶり」によって原子の再配列を実現する.また,原子再配列の学理解明のため,高分解能透過型電子顕微鏡(HRTEM)によるその場観察を実施する.さらに,応用上重要な薄膜の品質を定量評価するため,電流印加前後における薄膜の機械特性・電気特性について調査を行う.本年度の研究実績は以下のとおりである.
    <BR>
    1:密着強度試験および電流条件の最適化:電流印加前後における金属薄膜には,原子の再配列に伴う機械特性変化が生じる.ここでは,薄膜の機械特性を定量的に評価するため,密着強度試験を実施した.初年度はまず安定金属のAu,酸化しやすいCu,Tiを実験対象として選定し,電流印加前後の機械特性を比較した.その結果いずれの金属に対しても密着強度を向上させることに成功した.
    2:電気特性評価:独自に開発したナノ分解能を有するマイクロ波原子間力顕微鏡を本研究対象である金属薄膜の導電性評価に適用すべく,初年度はまず金属・半導体のナノ材料を評価し,独自プローブの分解能について調査を実施した.
    3:10MHz以上の高周波電流印加装置の構築:特に高い周波数領域(10MHz以上)の電流印加を実現するため,電源および電流印加プローブを新規に構築した.
    4:電流印加前後における結晶構造変化の解析:各種条件によって変化した試料の結晶構造解析をX線回折装置(XRD)および電子線後方散乱回折(EBSD)により分析した.これにより,本手法によって材料中に結晶粒の増大や双晶構造の増加などが生じることを確認した.
    初年度に実施した薄膜の強度試験・導電率評価の実験については概ね順調に進展している.また,概要に述べたとおり,結晶構造の解析により,特殊な結晶状態が増加することも確認されており,当初の計画の想定より多くの知見が得られている.一方,当初予定していた原子配列変化の動的挙動の可視化については,観察用ホルダーの開発に遅れが出ており,次年度の課題となっているが,総合的には初年度は概ね順調に進展していると言える.
    2年目の研究計画では引き続き薄膜の強度試験・導電率評価を実施し,異なる材料の特に結晶構造に着目した実験を実施する.また,原子配列変化の動的挙動の可視化に向け,独自の観察用ホルダー開発に着手する.さらに,高周波電流と原子の力学的相互作用と,その結果引き起こされる原子再配列のメカニズム解明を目指し,計算力学による解析に着手する.

  5. Fabrication and application of nanoscroll by self-deformation based on thin film residual stress

    Grant number:18K13657  2018.4 - 2020.3

    Grant-in-Aid for Early-Career Scientists

    TOKU Yuhki

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    Authorship:Principal investigator 

    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

    In this study, we have created a nanoscroll by using Self-deformation of coated nanobelt. The self deformation was achieved controlling the distribution of the residual stress on the longitudinal direction of nanobelt. First, it was clarified that various dimensions of the core material SnO2 nanobelts greatly depended on the pressure in the furnace during thermal sublimation, and the control of the cross-sectional aspect ratio was realized. As a result, we have created a nanobelt with the optimum shape for forming a nanoscroll, and succeeded in creating the nanoscroll in which the curvature changes in the longitudinal direction from a linear nanobelt. In addition, we also applied the nanobelt to a high-sensitivity gas sensor, which was initially unplanned. The existence of a significant crystal plane for gas detection was confirmed.

  6. Creation and development of high-order nano-space structures through innovative control of stress field

    Grant number:17H06146  2017.5 - 2022.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (S)

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    Authorship:Coinvestigator(s)  Grant type:Competitive

  7. 次世代エレクトロニクス実装ナノワイヤ面ファスナーの高強度化・高機能化

    Grant number:17H01236  2017.4 - 2018.3

    巨 陽

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    Authorship:Coinvestigator(s) 

    本研究は、ナノワイヤにコーティングした金属薄膜の残留応力を制御することによりナノワイヤの機械的な永久曲げ変形を実現し、ナノワイヤのフック&ループ構造を有したこれまでにない電気伝導ナノワイヤ面ファスナーを創出する。さらに、ナノワイヤのフック&ループ構造により発現する力学現象を解明し、常温での電気伝導接合技術を確立する。ナノワイヤ面ファスナーの接合強度、電気伝導および熱伝導の極限に挑戦することにより、従来のはんだ実装技術では成し得ないパワーデバイスの高温環境下での使用やフレキシブル基板への接続などを可能にする次世代エレクトロニクス実装技術を開発する。
    本年度は以下の実績を得た。
    (Ⅰ-1)超低密度ポーラスアルミナの開発
    細孔の大きさおよび孔間の間隙を広範囲で制御可能な独創的な二段階陽極酸化プロセスを新たに開発し、いままでは実現困難であったポーラスアルミナの低密度化を行った。第一段階の陽極酸化では、陽極酸化においてくぼみ形成の前処理を行うことによって細孔の数や間隔のコントロールを実現した。このプロセスでは、従来使用されているシュウ酸、硫酸ではなく、大きなセルが形成可能なリン酸を使用し、高電圧硬質陽極酸化を実現することにより、大きな細孔間隔を確保する。大きなセルを得るための第一段階の陽極酸化では、形成される細孔も大きいため、液温60 ℃のリン酸クロム水溶液で1時間ウェットエッチングを行い、第一段階の陽極酸化でアルミニウム箔上に形成されたポーラスアルミナのみを除去した。その後、小さな細孔が形成できる硫酸を用いて、第二段階の陽極酸化を行った。新たに開発した二段階陽極酸化法により、第一段階でできたくぼみを起点として細孔が成長することによって、低密度ポーラスアルミナの作製を実現した。
    29年度が最終年度であるため、記入しない。
    29年度が最終年度であるため、記入しない。

  8. Fabrication of Core Nanocoil by Self-deformation Technique

    Grant number:16K21093  2016.4 - 2018.3

    TOKU Yuhki

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    Authorship:Principal investigator 

    Grant amount:\4160000 ( Direct Cost: \3200000 、 Indirect Cost:\960000 )

    Magnetic recording has become high-density and miniaturization. According to this, the local detection technique of electromagnetic properties at nanoscale becomes extremely high demand. Researchers have spent much effort to detect the magnetic properties at nanoscale, which resulted in the development of several devices. For example, magnetic force microscope is a kind of scanning probe microscope, which detects the magnetic field of the sample surface using a magnetized probe. However, a quantitative measurement is sometimes difficult because the atomic force affects the detection results.
    In this study, we demonstrated the spiral formation of the coated nanowire by self-deformation technique based on the residual stress of the thin film. The metal coated nanowire spirally formed with high conductivity. The electrical and magnetic properties of the coil was investigated. The coil is possible to be used as an electromagnet to detect the electromagnetic properties of nanomaterials.

  9. 自己変形発現によるナノコイル形成技術を利用したナノインダクタ探針の開発

    2013.4 - 2015.3

    科学研究費補助金 

    徳 悠葵

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    Authorship:Principal investigator 

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Teaching Experience (On-campus) 24

  1. Science of Materials I

    2020

  2. Mechanical and Aerospace Engineering Seminar

    2020

  3. Fundamentals of Design

    2020

  4. 機械・航空宇宙工学序論

    2020

  5. Exercises in Material Characterization and Mechanics B

    2020

  6. Exercises in Material Characterization and Mechanics A

    2020

  7. Advanced Lectures on Fracture Mechanics

    2020

  8. 破壊強度学特論

    2019

  9. 機械・航空宇宙工学序論

    2019

  10. 材料科学第1A

    2019

  11. 設計基礎論B

    2019

  12. 材料力学第1及び演習

    2018

  13. Automobile Engineering Laboratory Ⅱ

    2018

  14. 機械・航空工学科実験第1・第2

    2018

  15. 設計基礎論B

    2018

  16. 材料力学及び演習

    2017

  17. 機械・航空工学科実験第1・第2

    2017

  18. Automobile Engineering Laboratory Ⅱ

    2017

  19. 機械・航空工学科実験第1・第2

    2016

  20. Automobile Engineering Laboratory Ⅱ

    2016

  21. 材料力学及び演習

    2016

  22. Automobile Engineering Laboratory Ⅱ

    2015

  23. 機械・航空工学科実験第1・第2

    2015

  24. 物理学実験

    2015

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Teaching Experience (Off-campus) 15

  1. 材料力学及び演習

    Nagoya University)

  2. 設計基礎論B

    Nagoya University)

  3. 破壊強度学特論

    Nagoya University)

  4. 機械・航空工学科実験第1・第2

    Nagoya University)

  5. 機械・航空工学科実験第1・第2

    Nagoya University)

  6. 機械・航空宇宙工学序論

    Nagoya University)

  7. 機械・航空宇宙工学序論

    Nagoya University)

  8. 材料科学第1A

    Nagoya University)

  9. 材料科学第1A

    Nagoya University)

  10. 材料力学第1及び演習

    Nagoya University)

  11. 材料力学及び演習

    Nagoya University)

  12. Automobile Engineering Laboratory Ⅱ

    Nagoya University)

  13. Automobile Engineering Laboratory Ⅱ

    Nagoya University)

  14. Automobile Engineering Laboratory Ⅱ

    Nagoya University)

  15. Automobile Engineering Laboratory Ⅱ

    Nagoya University)

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