Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Scientific Publishers  

Fe₂O₃ holds promising n-type semiconductor material in the field of solar water splitting due to its excellent photocatalytic properties. However, the photoelectrochemical performance of Fe₂O₃ is limited by its inherent properties such as poor conductivity, and charge separation efficiency owing to its recombination rate. Therefore, researchers are more focused on nanostructuring, doping, and surface coating to overcome these issues of Fe₂O₃. In this study, we have investigated a low-cost way to fabricate a Ti coating layer on a high-density Fe₂O₃ single-crystal nanowire array for solar water splitting. Firstly, we have prepared a high-density single-crystal Fe₂O₃ nanowire array at lower temperatures by a new approach stress-induced atomic diffusion method. Thereafter, the prepared nanowire array was coated by Ti film using RF sputtering. The optimal film thickness of 13 nm titanium coatings layer into Fe₂O₃ single crystal nanowire array exhibited a high photocurrent density of 1.36 mA/cm² at 1.23 V versus RHE and solar to hydrogen conversion efficiency (STH) of 1.67%, which could be resulting from adjusted optoelectronic properties of the nanowires.

DOI： 10.1166/mex.2024.2704

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

DOI： 10.1016/j.ijpvp.2024.105178

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

<p>In the present paper, the multiple applications of high-density pulsed electric current (HDPEC) with current densities between 100 and 200 A/mm² made fatigue crack growth (FCG) slow, in which a current density of more than 150 A/mm² provided high efficiency to refrain from FCG. The application of multiple HDPECs under the current density of 200 A/mm² showed a significantly reduced fatigue crack growth rate (FCGR). The fracture surfaces without the HDPEC effect showed signs of FCG along the crystal structure elongated in the rolling direction, on the other hand, a series of welded joints were formed at the crack tips due to the effect of applying multiple HDPECs, which provided different patterns of FCG leading to crack arrest. When initial HDPEC is applied in a short crack under the same HDPEC condition, it shows partial welding at the crack tip, while more concentrated welding at the crack tip by moderate Joule-heating is shown as fatigue progresses and the fatigue crack length increases. Elemental analysis by energy-dispersive X-ray spectroscopy and crystallographic analysis by electron backscatter diffraction also provided the microstructure features at the crack tip subjected to the application of multiple HDPECs. It is most efficient to perform in a short crack with multiple applications, and applying multiple manners as the crack progresses contributes to the accumulated improvement of fatigue properties by slowing the FCGR based on each application.</p>

DOI： 10.1299/mej.24-00015

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

<p>In this paper, a series of molecular dynamics (MD) simulations was performed to identify the high-temperature tensile properties of nanostructured polycrystalline CoCrCuFeNi high entropy alloy (HEA). The mechanism of strength reduction at elevated temperatures was understood through nanostructure observation such as phase transformation and dislocation evolution in MD simulation. The applicability of this material from room temperature to 1200 ℃ as a high-temperature use of structural material was identified. The stress-strain curve was found to gradually decrease ultimate tensile strength and yield stress as the temperature applied to the material increases. The elastic modulus decreases rapidly at slightly high temperatures but decreases gradually as it goes to the extremely high temperatures. Face-centered cubic (FCC)→hexagonal close-packed (HCP) phase transformation, which is energetic process between atoms due to tensile loading, was revealed. From the vicinity of the yield stress to the quasi-plastic regime, it competitively contributes to tensile properties between FCC→HCP phase transformation and growth of voids. In dislocation analysis, the typical partial dislocations such as perfect, Shockley, stair-rod and others were measured, in which Shockley and stair-rod partial dislocations show its characteristics that contribute to tensile properties. The results in this study contribute to understanding the high-temperature applicability of nanostructured polycrystalline CoCrCuFeNi HEA.</p>

DOI： 10.1299/mej.23-00551

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：ASME International  

Abstract

Molecular dynamics studies were performed to assess tensile and compressive behaviors at high temperatures up to 1200 °C for nanostructured polycrystalline AlCoCrFeNi high entropy alloy (HEA). As the temperature increased, the tensile yield stress, tensile/compressive ultimate strengths, and elastic modulus decreased, whereas the compressive yield stress remained constant. The temperature dependence of the phase structures (face-centered cubic (FCC) and hexagonal close-packed (HCP)) showed notable features between tension and compression. The HEA underwent FCC → HCP phase transformation when strained under both tension and compression. The evolution of the intrinsic stacking faults (ISFs) and extrinsic stacking faults (ESFs), which underwent FCC → HCP phase transformation, was observed. During compression, the ISFs → ESFs transition produced parallel twins. The evolution of mean dislocation length for the perfect, Shockley, and stair-rod partial dislocations was observed. Changes in the Shockley and stair-rod partial dislocations were observed after experiencing strain. The temperature dependence of the Shockley partial dislocation was high, whereas the stair-rod partial dislocation exhibited low-temperature dependence. From the simulation results, the structural usage of nanostructured polycrystalline AlCoCrFeNi HEA at elevated temperatures is recommended.

DOI： 10.1115/1.4063802

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

DOI： 10.1088/1361-6463/ad1469

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DOI： 10.1016/j.jallcom.2023.172892

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.msea.2023.145845

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.mtcomm.2023.107082

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.mtla.2023.101922

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

For the first time, the thermal stress-assisted formation of submicron pillars (SPs) from a high entropy alloy (HEA) thin film is made possible, and novel molecular dynamics (MD) simulations are proposed to assess the underlying mechanisms.

DOI： 10.1039/d3ra04759h

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

DOI： 10.1007/s11665-023-08522-z

Other Link： https://link.springer.com/article/10.1007/s11665-023-08522-z/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.msea.2023.145534

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

In this study, an energy-saving and highly efficient high-density pulsed electric current (HDPEC) method was used to improve the formability of the aluminum alloy A6061 after T6 heat treatment (A6061-T6). An interrupted tensile test was performed, and the HDPEC treatment was applied after tensile deformation. The results showed that the ductility of A6061-T6 improved by approximately 33% after three HDPEC treatments. The Vickers hardness and residual stress were measured to investigate the effect of the pulsed electric current on formability, and they were recovered after HDPEC treatment. Furthermore, the microstructural morphology and dislocation density were investigated to understand the mechanism of formability enhancement. Detailed analysis shows that the formability enhancement of A6061-T6 after HDPEC treatment is mainly attributed to dislocation elimination, while grain size and crystalline orientation changes are side effects. In addition, the results of equivalent heat treatments demonstrate that the athermal effect of the HDPEC treatment plays a crucial role in the removal of dislocations. Thus, due to the contribution of the athermal effect, HDPEC treatment realizes the advantages of low consumption and high efficiency, and can be dedicated to green processing and manufacturing of metallic materials.

DOI： 10.1007/s00170-023-11841-z

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

DOI： 10.1007/s10853-023-08721-y

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Other Link： https://link.springer.com/article/10.1007/s10853-023-08721-y/fulltext.html

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.mtcomm.2023.106892

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.engfailanal.2023.107230

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CiNii Research

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

Three-dimensional (3D) extracellular matrix (ECM) microenvironment is an important regulator of the stiffness of the tumors. Cancer cells require heterogeneous metabolic phenotypes to cope with resistance in the malignant process. However, how the stiffness of the matrix affects the metabolic phenotypes of cancer cells, is lacking. In this study, the young's modulus of the synthesized collagen-chitosan scaffolds was adjusted according to the percentage ratio of collagen to chitosan. We cultured non-small cell lung cancer (NSCLC) cells in four different microenvironments (two-dimensional (2D) plates, stiffest 0.5-0.5 porous collagen-chitosan scaffolds, middle stiff 0.5-1 porous collagen-chitosan scaffolds, and softest 0.5-2 porous collagen-chitosan scaffolds) to investigate the influence of the difference of 2D and 3D cultures as well as the 3D scaffolds with different stiffnesses on the metabolic dependency of NSCLC cells. The results revealed that NSCLC cells cultured in 3D collagen-chitosan scaffolds displayed higher capacity of mitochondrial metabolism and fatty acid metabolism than that cultured in 2D culture. The metabolic response of NSCLC cells is differential for 3D scaffolds with different stiffnesses. The cells cultured in middle stiff 0.5-1 scaffolds displayed a higher potential of mitochondrial metabolism than that of stiffer 0.5-0.5 scaffolds and softer 0.5-2 scaffolds. Furthermore, NSCLC cells culture in 3D scaffolds displayed drug resistance compared with that in 2D culture which maybe via the hyperactivation of the mTOR pathway. Moreover, the cells cultured in 0.5-1 scaffolds showed higher ROS levels, which were counterbalanced by an equally high expression of antioxidant enzymes when compared to the cells grown in 2D culture, which may be regulated by the increased expression of PGC-1α. Together, these results demonstrate that differences in the microenvironments of cancer cells profoundly impact their metabolic dependencies.

DOI： 10.1007/s13105-023-00960-6

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Other Link： https://link.springer.com/article/10.1007/s13105-023-00960-6/fulltext.html

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

DOI： 10.1002/adem.202300115

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Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.engfracmech.2023.109235

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CiNii Research

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

INTRODUCTION: Metabolic strategies in different microenvironments can affect cancer metabolic adaptation, ultimately influencing the therapeutic response. Understanding the metabolic alterations of cancer cells in different microenvironments is critical for therapeutic success. METHODS: In this study, we cultured non-small cell lung cancer cells in three different microenvironments (two-dimensional (2D) plates, soft elastic three-dimensional (3D) porous 2 wt% scaffolds, and stiff elastic 3D porous 4 wt% scaffolds) to investigate the effects of different matrix elasticity as well as 2D and 3D culture settings on the metabolic adaptation of cancer cells. RESULTS: The results revealed that PGC-1α expression is sensitive to the elasticity of the 3D scaffold. PGC-1α expression was markedly increased in cancer cells cultured in stiff elastic 3D porous 4 wt% scaffolds compared with cells cultured in soft elastic 3D porous 2 wt% scaffolds or 2D plates, enhancing mitochondrial biogenesis and oxidative stress resistance of non-small cell lung cancer through increased reactive oxygen species (ROS) detoxification capacity. However, phosphofructokinase-1 (PFK-1) expression, a key rate-limiting enzyme in glycolysis, did not change significantly in the three microenvironments, indicating that microenvironments may not affect the early stage of glycolysis. Conversely, monocarboxylate transporter 1 (MCT1) expression in 3D culture was significantly reduced compared to 2D culture but without significant difference between soft and stiff scaffolds, indicating that MCT1 expression is more sensitive to the shape of the different cultures of 2D and 3D microenvironment surrounding cells but is unaffected by the scaffold elasticity. CONCLUSIONS: Together, these results demonstrate that differences in the microenvironment of cancer cells profoundly impact their metabolic response.

DOI： 10.1007/s12195-022-00751-x

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Other Link： https://link.springer.com/article/10.1007/s12195-022-00751-x/fulltext.html

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

Abstract

A non-contact quantitative method for measuring the electrical conductivity of a SnO₂ nanobelt field-effect transistor (FET) with nanometer-scale spatial resolution is reported. The topography and microwave images of the nanobelt FET were measured by microwave atomic force microscopy (M-AFM) under a constant source voltage and different back-gate voltages. The output characteristics of the nanobelt FET were measured using a two-probe measurement method. The local conductivity of the SnO₂ nanobelt FET measured by M-AFM concurred with that obtained by the two-probe measurement. Therefore, M-AFM is a promising method for measuring the local conductivity of nanomaterial FETs.

DOI： 10.35848/1882-0786/acaaf3

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Other Link： https://iopscience.iop.org/article/10.35848/1882-0786/acaaf3/pdf

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Accidental chemotherapy extravasation exacerbates the side effects of anticancer drugs. Therefore, drug-delivery nanocarriers should be designed to avoid persistent drug release at off-target sites and promote burst drug release at on-target. Considering these requirements, poly(allylamine)-co-poly(allylurea) (PAU), a ureido-derivatized temperature responsive polymer with upper critical solution temperature (UCSTs), is an ideal material. This report describes the fabrication, characterization, and in vitro cellular toxicity of PAU polymer-grafted magnetic mesoporous silica nanoparticles as drug-delivery nanocarriers. A UCST of 43 °C and an ultranarrow transition temperature range of 39-43 °C was realized, ensuring that the nanocarriers suppressed undesirable leakage to below 10 % of the drug loading for 8 h in the absence of a thermal stimulus. A drug release burst of up to 75 % of the drug loading was achieved within 30 min after the stimulus, reducing the viability of the in vitro cancer cells to 12 %. Therefore, the ureido-derivatized polymer is one of the most suitable gatekeepers for drug-delivery nanocarriers.

DOI： 10.1016/j.bioadv.2022.213026

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

Acute myeloid leukemia (AML) is the most lethal leukemia with an extremely poor prognosis and high relapse rates. In leukemogenesis, adhesion abnormalities can readily guide an imbalance between hematopoietic progenitor cells and bone marrow stromal cells, altering the normal hematopoietic bone marrow microenvironment into leukemic transformation that enhances leukemic proliferation. Here, we have firstly studied the PLEKHA7 expression in leukemic cells to assess their growth capability affected by the restoration of PLEKHA7 in the cells. The efficacy of PLEKHA7-loaded cRGD-mediated PEGylated cationic lipid nanoparticles for efficient PLEKHA7 delivery in leukemic cells as well as the effect of PLEKHA7 on the regulated induction of AML behavior and growth alterations were investigated. PLEKHA7 re-expression diminished colony-forming ability and reinforced the incidence of growth retardation without apoptosis in AML cell lines. PLEKHA7 regulated the restoration of cell surface adhesion and integrity during normal homeostasis. Our findings revealed that PLEKHA7 functions as a behavior and growth modulator in AML. To our knowledge, the role of PLEKHA7 in AML had not been studied previously and our data could be exploited for further mechanistic studies and insights into altering human AML behavior and growth.

DOI： 10.1016/j.bbiosy.2022.100045

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PubMed

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

DOI： 10.1016/j.vacuum.2021.110855

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

DOI： 10.1016/j.ijfatigue.2021.106639

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Language：English   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

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

DOI： 10.1016/j.matlet.2020.129121

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

DOI： 10.1016/j.commatsci.2020.110214

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

DOI： 10.1016/j.ijmecsci.2020.106102

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

DOI： 10.1016/j.scriptamat.2020.03.056

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

DOI： 10.1038/s41598-020-62259-6

PubMed

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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PubMed

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

DOI： 10.1016/j.apsusc.2018.09.205

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

DOI： 10.1063/1.5066599

PubMed

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

DOI： 10.1038/s41598-018-37693-2

PubMed

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

DOI： 10.3390/ma11112168

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PubMed

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

DOI： 10.1088/1351-6528/aace96

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

DOI： 10.1088/1361-6528/aac284

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

DOI： 10.1098/rsos.172126

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

Scopus

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

Language：English   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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PubMed

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

DOI： 10.1016/j.ijfatigue.2017.06.021

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

DOI： 10.1039/c7ra03298f

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

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

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

DOI： 10.1166/nnl.2014.1776

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

DOI： 10.1049/mnl.2012.0665

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

DOI： 10.1166/nnl.2010.1058

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

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

CiNii Books

CiNii Research

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% H₂ was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H₂ gas at room temperature was achieved by Pd functionalization.

DOI： 10.1299/jsmemp.2016.24.406

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmemp.2016.24.413

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmecmd.2016.29.4_232

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmemp.2015.23._722-1_

CiNii Books

CiNii Research

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-

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CiNii Research

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-

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CiNii Research

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 Books

CiNii Research

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 Books

CiNii Research

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 Books

CiNii Research

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 Books

CiNii Research

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 Books

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmetohoku.2013.49.51

CiNii Books

CiNii Research

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 Books

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmemp.2013.21._511-1_

CiNii Books

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmemp.2012.20._330-1_

CiNii Books

CiNii Research

Language：English   Publisher：The Japan Society of Mechanical Engineers  

CiNii Books

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 Books

CiNii Research

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 Books

CiNii Research

Language：Japanese   Publisher：The Japan Society of Mechanical Engineers  

DOI： 10.1299/jsmeth.2010.45.12

CiNii Books

CiNii Research

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

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

Event date： 2019.12

Language：Japanese   Presentation type：Oral presentation (keynote)  

DOI： 10.1109/MHS48134.2019.9249283

Scopus

Event date： 2019

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2019.31.2F22

Event date： 2019

Language：English   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmeatem.2019.1009D1000

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

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

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

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

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

Event date： 2019

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2019.32.2D23

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

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

Event date： 2019

Language：Japanese   Presentation type：Oral presentation (general)  

<p>Recently, Cu₂O 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 Cu₂O 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 Cu₂O in photocathode to absorb sunlight efficiently, the short diffusion length of minority cariers, and the Cu₂O 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 Cu₂O photocathode. The present study aimed to improve STH and stability in Cu₂O photocathode for water splitting by optimizing morphology of Cu₂O 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 Cu₂O nanostructures exhibited maximum photocurrent density of 4.58 mA/cm² 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

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

Event date： 2019

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2019.32.1F14

Event date： 2018.12

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1109/MHS.2018.8886953

Scopus

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2018.30.1H16

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2018.30.1A18

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.J2220104

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.J0450402

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.J0270101

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.J0220304

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.J2220103

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebiofro.2018.29.1B16

Event date： 2018

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemp.2018.26.721

CiNii Research

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 SnO₂ is considered to be an important one, because it is a typical n-type semiconductor. Particularly, SnO₂ 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. SnO₂ nanobelt is generally synthesized by thermal evaporation method, but it is difficult to control the shape, size and density of SnO₂ 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 SnO₂ 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

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

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. Cu₂O 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 Cu₂O 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

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

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

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

Event date： 2018

Language：English   Presentation type：Oral presentation (general)  

Event date： 2018

Language：English   Presentation type：Oral presentation (general)  

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

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. Cu₂O 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/cm². 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, Cu₂O/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

Event date： 2017

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2017.29.1F42

Event date： 2017

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2017.J0250205

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 CuSO₄·5H₂O 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/cm² 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

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

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 Al₂O₃, Ge, and ZrO₂ was evaluated using this theoretical model.

DOI： 10.1299/jsmecmd.2017.30.340

CiNii Research

Event date： 2017

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebiofro.2017.28.1A24

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/cm²) 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

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

Event date： 2017

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2017.29.2B35

Event date： 2017

Language：English   Presentation type：Oral presentation (general)  

Scopus

Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2016.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋大学   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2016.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2016

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebiofro.2016.27.B215

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 Cu₂O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu₂O solar battery is much lower than theoretical value. In this research, Cu₂O/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 Cu₂O/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

Event date： 2016

Language：Japanese   Presentation type：Oral presentation (general)  

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

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% H₂ was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H₂ gas at room temperature was achieved by Pd functionalization.</p>

DOI： 10.1299/jsmemp.2016.24.406

CiNii Research

Event date： 2016

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

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

CiNii Research

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>

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>

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>

Event date： 2016

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

DOI： 10.1299/jsmecmd.2016.29.4_232

CiNii Research

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>

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>

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>

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>

Event date： 2016

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

DOI： 10.1299/jsmemp.2016.24.413

CiNii Research

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

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

Event date： 2015.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.10

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015.8

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2015

Language：English   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmeatem.2015.14.212

Event date： 2015

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemp.2015.23._722-1_

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

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

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-

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-

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-

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

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.

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

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

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

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

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

Event date： 2015

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

DOI： 10.1299/jsmemp.2015.23._722-1_

CiNii Research

Event date： 2014.7

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

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

Event date： 2013.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

DOI： 10.1299/jsmetohoku.2013.49.51

CiNii Research

Event date： 2013.9

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2013

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemp.2013.21._511-1_

CiNii Research

Event date： 2012.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

DOI： 10.1299/jsmemp.2012.20._330-1_

CiNii Research

Event date： 2012.8

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2011.9

Language：English   Presentation type：Oral presentation (general)  

Country：Japan  

Event date： 2011.6

Language：English   Presentation type：Oral presentation (general)  

Country：United States  

Event date： 2011

Language：English   Presentation type：Oral presentation (general)  

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

Event date： 2010.10

Language：English   Presentation type：Oral presentation (general)  

Country：Singapore  

Event date： 2010.10

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

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

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

Event date： 2010.3

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

DOI： 10.1299/jsmeth.2010.45.12

CiNii Research

Event date： 2009.11

Language：Japanese   Presentation type：Oral presentation (general)  

Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

<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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

<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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学  

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 Al₂O₃, Ge, and ZrO₂ was evaluated using this theoretical model.

Language：Japanese   Presentation type：Oral presentation (general)  

<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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学  

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

<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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学  

Language：Japanese   Presentation type：Oral presentation (general)  

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>

Language：English   Presentation type：Oral presentation (general)  

Venue：早稲田大学  

Language：English   Presentation type：Oral presentation (general)  

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 CuSO₄·5H₂O 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/cm² 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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

<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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学  

Language：Japanese   Presentation type：Oral presentation (general)  

<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% H₂ was achieved at 200°C for pure CNT sheet and a sensitivity of 2.5% towards H₂ gas at room temperature was achieved by Pd functionalization.</p>

Language：English   Presentation type：Oral presentation (general)  

Venue：早稲田大学  

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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>

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>

Language：Japanese   Presentation type：Oral presentation (general)  

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 SnO₂ is considered to be an important one, because it is a typical n-type semiconductor. Particularly, SnO₂ 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. SnO₂ nanobelt is generally synthesized by thermal evaporation method, but it is difficult to control the shape, size and density of SnO₂ 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 SnO₂ nanobelts. From the above, it is expected that the improvement of flexibility and transparency of a transparent conductive film could be realized.</p>

Language：English   Presentation type：Oral presentation (general)  

Venue：New York, USA  

Language：English   Presentation type：Oral presentation (general)  

Venue：Xi'an, China  

Language：English   Presentation type：Oral presentation (general)  

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.

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Venue：Lisbon, Portugal  

Language：English   Presentation type：Oral presentation (general)  

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学  

Language：English   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

<p>Recently, Cu₂O 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 Cu₂O 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 Cu₂O in photocathode to absorb sunlight efficiently, the short diffusion length of minority cariers, and the Cu₂O 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 Cu₂O photocathode. The present study aimed to improve STH and stability in Cu₂O photocathode for water splitting by optimizing morphology of Cu₂O 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 Cu₂O nanostructures exhibited maximum photocurrent density of 4.58 mA/cm² 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>

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 Cu₂O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu₂O solar battery is much lower than theoretical value. In this research, Cu₂O/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 Cu₂O/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>

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. Cu₂O 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/cm². 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, Cu₂O/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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神戸大学  

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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>

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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>

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>

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>

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>

Language：Japanese   Presentation type：Oral presentation (general)  

<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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：九州大学  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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. Cu₂O 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 Cu₂O 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>

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋大学  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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/cm²) 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>

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>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

<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 10⁶ Ω・m was achieved successfully.</p>

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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.

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.

Language：English   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmeatem.2015.14.212

CiNii Research

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

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.

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.

Language：English   Presentation type：Oral presentation (general)  

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.

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.

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.

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.

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.

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.

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.

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.

Language：English   Presentation type：Oral presentation (general)  

Venue：Kaohsiung, Taiwan  

Language：Japanese   Presentation type：Oral presentation (general)  

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.

Language：Japanese   Presentation type：Oral presentation (general)  

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.

Language：English   Presentation type：Oral presentation (general)  

Language：English   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

Language：Japanese   Presentation type：Oral presentation (general)  

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.

Language：Japanese   Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

<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>

Presentation type：Oral presentation (general)  

<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>

Language：English   Presentation type：Oral presentation (general)  

<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>

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

CiNii Research

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

CiNii Research

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

CiNii Research

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

CiNii Research

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

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebiofro.2016.27.b215

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.j0450402

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2020.j04209

CiNii Research

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

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

<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

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmebio.2019.32.1f14

CiNii Research

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

CiNii Research

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. Cu₂O 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/cm². 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, Cu₂O/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

CiNii Research

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 Cu₂O solar cells have a high theoretical energy conversion efficiency with a very low cost. However, the actual efficiency of Cu₂O solar battery is much lower than theoretical value. In this research, Cu₂O/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 Cu₂O/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

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

<p>Recently, Cu₂O 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 Cu₂O 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 Cu₂O in photocathode to absorb sunlight efficiently, the short diffusion length of minority cariers, and the Cu₂O 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 Cu₂O photocathode. The present study aimed to improve STH and stability in Cu₂O photocathode for water splitting by optimizing morphology of Cu₂O 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 Cu₂O nanostructures exhibited maximum photocurrent density of 4.58 mA/cm² 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

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmemecj.2018.j2220104

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)  

DOI： 10.7566/jpscp.22.011018

CiNii Research

Language：English   Presentation type：Oral presentation (general)  

DOI： 10.1299/jsmeatem.2019.1009d1000

CiNii Research

Language：Japanese   Presentation type：Oral presentation (general)