研究者詳細 - 石川　健治

論文 - 石川　健治

分割表示 424 件中 161 - 180 件目／全件表示 >>

Characterization of a microsecond pulsed non-equilibrium atmospheric pressure Ar plasma using laser scattering and optical emission spectroscopy 査読有り

Jia, FD; Wu, Y; Min, Q; Su, MG; Takeda, K; Ishikawa, K; Kondo, H; Sekine, M; Hori, M; Zhong, ZP

PLASMA SCIENCE & TECHNOLOGY 22 巻 ( 6 ) 頁： 065404 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Plasma Science and Technology

A non-equilibrium atmospheric pressure argon (Ar) plasma excited by microsecond pulse is studied experimentally by laser scattering and optical emission spectroscopy (OES), and theoretically by collisional-radiative (CR) model. More specifically, the electron temperature and electron density of plasma are obtained directly by the laser Thomson scattering, the gas temperature is measured by laser Raman scattering, the optical emissions of excited Ar states of plasma are measured by OES. The laser scattering results show that the electron temperature is about 1 eV which is similar to that excited by 60 Hz AC power, but the gas temperature is as low as 300 K compared to about 700 K excited by 60 Hz AC power. It is shown that the microsecond pulsed power supply, rather than nanosecond ones, is short enough to reduce the gas temperature of atmospheric pressure plasma to near room temperature. The electron temperature and electron density are also obtained by CR model based on OES, and find that the intensities of the optical emission intensity lines of 727.41, 811.73, 841.08, 842.83, 852.44 and 912.86 nm of Ar can be used to characterize the behavior of electron density and electron temperature, it is very useful to quickly estimate the activity of the atmospheric pressure Ar plasma in many applications.

DOI： 10.1088/2058-6272/ab84e2

Web of Science

Scopus

Electron spin resonance as a tool to monitor the influence of novel processing technologies on food properties 査読有り国際共著 Open Access

Barba, FJ; Roohinejad, S; Ishikawa, K; Leong, SY; Bekhit, AEA; Saraiva, JA; Lebovka, N

TRENDS IN FOOD SCIENCE & TECHNOLOGY 100 巻頁： 77 - 87 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Trends in Food Science and Technology

Background: Nowadays, electron spin resonance (ESR) is widely used as a powerful, non-destructive and very sensitive technique for the detection of free radicals in food systems. It can be applied for the direct identification of highly reactive oxygen species, organic and inorganic paramagnetic species and screening of food for potential toxicity. Its applications cover investigating food oxidative stability and properties of irradiated foods including fruits and vegetables, meats and fishes, spices, cereal grains, and oil seeds. Scope and approach: This review aims at providing specialists in food science and industry with the fundamentals of ESR spectroscopy, typical radicals present in foods and their sources, ESR modalities, and detailed account for the use of the technology for evaluation of the physicochemical and nutritional properties of foods. Examples illustrating ESR applications for the evaluation of the effects of innovative and emerging technologies (ionizing radiation, high pressures, pulsed electric fields, cold plasma and ultrasonication) are discussed. Key findings and conclusions: ESR can be used for the identification/quantification of free radicals in foods, for spin-label oximetry, estimation of free radical scavenging, food stability, and chelating activity, with particular interest for food processed using innovative technologies, with the main advantages of its high sensitivity, specificity, and low amounts of sample needed and nowadays many types of ESR instruments are commercially available. However, due to the different nature of foods, the development of novel ESR techniques and methods of analysis specially designed to study foods is of great interest in the future.

DOI： 10.1016/j.tifs.2020.03.032

Web of Science

Scopus

Electronic properties and primary dissociation channels of fluoromethane compounds 査読有り

Hayashi, T; Ishikawa, K; Sekine, M; Hori, M

JAPANESE JOURNAL OF APPLIED PHYSICS 59 巻 ( SJ ) 頁： SJJE02 2020年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

We investigated fluoromethane compounds (CF<inf>4</inf>, CF<inf>3</inf>, CHF<inf>3</inf>, CH<inf>2</inf>F<inf>2</inf>, and CH<inf>3</inf>F) to examine their electronic properties and primary dissociation channels by using computational chemistry. For the electron attachment process, it was very important to represent the observed negative mass spectrum as a function of electron energy that calculation by the MP2 method for the negative ion and subsequent calculation by the EOMCCSD method were used to more accurately estimate the ground and the first excited states of the negative ion. In the evaluation of dissociation channels through the excitation process, the structure change of the excited fragment (from pyramidal to planar) was taken into account. Evaluation of Jahn-Teller distortion for the highly symmetrical CHF<inf>3</inf> and CH<inf>3</inf>F was also very important to estimate the fragmentation process through the excitation. The calculated results after these treatments gave satisfactory representation of the experimental values. Moreover some predictions of experimentally unknown values are proposed.

DOI： 10.35848/1347-4065/ab7e3f

Web of Science

Scopus

Synthesis of isolated carbon nanowalls via high-voltage nanosecond pulses in conjunction with CH4/H2 plasma enhanced chemical vapor deposition 査読有り

Ichikawa, T; Shimizu, N; Ishikawa, K; Hiramatsu, M; Hori, M

CARBON 161 巻頁： 403 - 412 2020年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Carbon

Carbon nanowalls (CNWs) are vertically standing, interconnecting flake- or wall-like collections of graphene sheets. In the present work, this material was synthesized by applying precisely controlled high-voltage nanosecond pulses to a substrate using an inductor energy storage circuit in a radical-injection plasma-enhanced chemical vapor deposition system, employing a CH<inf>4</inf>/H<inf>2</inf> plasma. The resulting interconnected networks had a low density of CNWs with large average wall-to-wall distances. During the application of short-period pulses, the entire substrate surface was uniformly activated, thus enhancing the adsorption of carbon precursors and preventing CNW nucleation. As a result, an amorphous carbon film covered the surface of the substrate and a low CNW density was obtained with average wall-to-wall distances greater than 700 nm. On the basis of these results, the growth mechanism of CNWs was modeled.

DOI： 10.1016/j.carbon.2020.01.064

Web of Science

Scopus

Gas-phase and film analysis of hydrogenated amorphous carbon films: Effect of ion bombardment energy flux on sp2 carbon structures 査読有り

Sugiura, H; Ohashi, Y; Ishikawa, K; Kondo, H; Kato, T; Kaneko, T; Takeda, K; Tsutsumi, T; Hayashi, T; Sekine, M; Hori, M

DIAMOND AND RELATED MATERIALS 104 巻 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Diamond and Related Materials

Hydrogenated amorphous carbon (a-C:H) films comprise nanoclustering graphites (nc-G), fused aromatic rings (nR), and olefinic chain clusters (nC) of sp2-bonded carbons in an sp3 matrix. In this study, the sp2 composition of the nc-G, nR and nC in a-C:H films is found to be determined by the ion bombardment energy flux (Γ<inf>Ei</inf>), which can be estimated as the product of ion bombardment energy and ion flux onto the deposited surface, in plasma-enhanced chemical vapor deposition using a plasma mixture of H<inf>2</inf> and CH<inf>4</inf> gases with the H radical injection method. The sp2 composition is analyzed using Raman spectroscopy and near-edge X-ray absorption structure spectroscopy. a-C:H becomes increasingly graphitized with increasing Γ<inf>Ei</inf>. The precise control of the sp2 C structure composition can be achieved by controlling the very-high-frequency input power and radio frequency input bias power via the ion flux and ion bombardment energy.

DOI： 10.1016/j.diamond.2019.107651

Web of Science

Scopus

In-Liquid Plasma Synthesis of Nanographene with a Mixture of Methanol and 1-Butanol 査読有り

Ando, A; Ishikawa, K; Takeda, K; Ohta, T; Ito, M; Hiramatsu, M; Kondo, H; Sekine, M; Hori, M

CHEMNANOMAT 6 巻 ( 4 ) 頁： 604 - 609 2020年4月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Chemnanomat

Nanometer-size graphene sheets (nanographene) were synthesized by the in-liquid plasma method employing a mixture of alcohols. Pure methanol in-liquid plasma was found to not synthesize any nanographene. Pure ethanol synthesized nanographene with high crystallinity. Highly crystalline nanographene with a narrow full width-half maximum of the Raman scattering G-band (FWHM<inf>G</inf>) was obtained by mixing 1-butanol with methanol. This is due to the formation of carbon ring structures being inhibited by the addition of methanol. The ratio of added methanol determined the nanographene crystallinity and yield under a trade-off relationship, allowing the crystallinity and nanographene yield to be controlled by controlling the ratio. Gas chromatography-mass spectrometric analysis of by-products in the liquids’ supernatant showed that the crystallinity of the synthesized nanographene correlated with the ratio of carbon over oxygen of the alcohol precursors (C/O), i. e., the amount of hydroxyl groups in the liquids, and hence controlling the C/O ratio can be used to control the graphene crystallinity in the in-liquid plasma synthesis.

DOI： 10.1002/cnma.201900676

Web of Science

Scopus

計算科学による新規エッチングガスの探索査読有り

林俊雄, 関根誠, 堀勝, 石川健治

応用物理学会学術講演会講演予稿集 2020.1 巻 ( 0 ) 頁： 1585 - 1585 2020年2月

プラズマ照射したカイワレ種子の吸水の時間推移評価査読有り

石川健治, Pankaj Attri, 奥村賢直, 古閑一憲, 有田涼, 佐藤僚哉, 田中颯, 廣松真弥, 鎌瀧晋礼, 松尾かよ, 山下大輔, 板垣奈穂, 堀勝, 白谷正治

応用物理学会学術講演会講演予稿集 2020.1 巻 ( 0 ) 頁： 1620 - 1620 2020年2月

イネ圃場における定期的な低温プラズマ処理による生育や収穫に対する検討 (III) 査読有り

北野英己, 水野寛子, 阿部明子, 湯浅元気, 東野里江, 橋爪博司, 石川健治, 田中宏昌, 松本省吾, 仁川進, 榊原均, 前島正義, 堀勝, 水野正明

応用物理学会学術講演会講演予稿集 2020.1 巻 ( 0 ) 頁： 1622 - 1622 2020年2月

Interaction of oxygen with polystyrene and polyethylene polymer films: A mechanistic study 査読有り国際共著

Fukunaga, Y; Longo, RC; Ventzek, PLG; Lane, B; Ranjan, A; Hwang, GS; Hartmann, G; Tsutsumi, T; Ishikawa, K; Kondo, H; Sekine, M; Hori, M

JOURNAL OF APPLIED PHYSICS 127 巻 ( 2 ) 2020年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Applied Physics

In this work, first principles calculations combined with advanced surface diagnostics are used to unravel the mechanisms of plasma oxygen interaction with organic films of interest for advanced patterning in semiconductor device manufacturing. Results from a combination of x-ray photoelectron spectroscopy (XPS) diagnosed oxygen plasma exposed polystyrene films and first principles modeling of organic films (polystyrene, polyethylene, and derivatives) provide insights into how organic films are oxidized by oxygen atoms. XPS measurements show the rapid formation of C-O structures and their saturation after oxygen exposure on both pristine and argon bombarded polystyrene samples. Quantum mechanics calculations confirm that C-OH formation can be immediate without recourse to previously formed dangling bonds. Multiple oxygen impacts are required for scission of pristine ethylene carbon strands. Therefore, ethylene films can be converted to polyols that are stable, whereas more likely strands are broken before polyol formation through the formation of water and C=O. On the contrary, intermediate compounds with adjacent C=O bonds are not likely to form stable structures. The combination of XPS measurements and modeling implies that the oxidation of polystyrene and polyethylene is self-limiting on both hydrogen saturated and dehydrogenated (after argon ion plasma bombardment) surfaces.

DOI： 10.1063/1.5127863

Web of Science

Scopus

Inactivation mechanism of fungal spores through oxygen radicals in atmospheric-pressure plasma 査読有り

Ito M., Hashizume H., Oh J.S., Ishikawa K., Ohta T., Hori M.

Japanese Journal of Applied Physics 60 巻 ( 1 ) 頁： 010503 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Japanese Journal of Applied Physics

A brief history of the development of our plasma technology for the disinfection of agricultural harvests is presented in this review. We focused on the influence of reactive oxygen species (ROS), e.g. ground-state oxygen atoms [O(3P j )], excited-state oxygen molecules [O2(1Δg)], and ozone (O3), generated from atmospheric-pressure plasmas on the inactivation of fungal spores under dry conditions. For elucidating the inactivation mechanisms, it is essential to reveal the key ROS. Using some powerful tools, we revealed that the dose of O(3P j ) strongly correlates with the inactivation of fungal spores when compared to those of another ROS, such as O2(1Δg) and O3. The balance of antioxidants in the spores is possibly modulated by O(3P j ), leading to oxidation of organelles in spores. Herein, we introduce and discuss how O(3P j ) contributes to the inactivation of fungal spores associated with in situ diagnostics of plasma generated ROS and in situ intracellular observations of a few fungal spore species.

DOI： 10.35848/1347-4065/abcbd1

Web of Science

Scopus

Leukocyte depletion and size-based enrichment of circulating tumor cells with pressure-sensing microfiltration system 査読有り Open Access

Kuboyama D., Onoshima D., Kihara N., Tanaka H., Hase T., Yukawa H., Ishikawa K., Odaka H., Hasegawa Y., Hori M., Baba Y.

21st International Conference on Miniaturized Systems for Chemistry and Life Sciences Microtas 2017 頁： 882 - 883 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：21st International Conference on Miniaturized Systems for Chemistry and Life Sciences Microtas 2017

We present a study of blood microfiltration system towards optimal approach of non-invasive liquid biopsy for cancer detection by circulating tumor cells (CTCs). Filtration behavior of a microfilter was experimentally analyzed for tumor cell isolation from leukocytes in whole blood. This approach achieved an average of >96% recovery of spiked tumor cells and >99% total leukocytes depletion.

DOI： 10.1021/acsmeasuresciau.2c00057

Open Access

Scopus

Cell deposition and isolation with micropipette control over liquid interface motion in microfluidic channel 査読有り

Onoshima D., Yukawa H., Hattori Y., Ishikawa K., Hori M., Baba Y.

21st International Conference on Miniaturized Systems for Chemistry and Life Sciences Microtas 2017 頁： 679 - 680 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：21st International Conference on Miniaturized Systems for Chemistry and Life Sciences Microtas 2017

We developed a microfluidic chip for depositing single cells in microwells using simple micropipette operation. Cells were delivered to microwells by the meniscus motion of liquid interface. The residue deposits of cells were redistributed with air injection, and the isolated single cells were stored in microwells. Different microwell sizes and depths were studied to evaluate the trapping possibility of cells. Medium replacement and cell viability staining with the isolated single cells were achieved in microwells.

Scopus

Etching characteristics of PECVD-prepared SiN films with CF4/D2 and CF4/H2 plasmas at different temperatures 査読有り

Hsiao, SN; Nguyen, TTN; Tsutsumi, T; Ishikawa, K; Sekine, M; Hori, M

2020 INTERNATIONAL SYMPOSIUM ON SEMICONDUCTOR MANUFACTURING (ISSM) 2020-December 巻 2020年

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IEEE International Symposium on Semiconductor Manufacturing Conference Proceedings

The dependences of plasmas (CF4/D2 and CF4/H2) on etch rates of the PECVD SiN films at different substrate temperatures were investigated. The CF4/D2 plasma exhibited higher etch rates than that for the CF4/D2 plasma at room temperature and higher. The optical emission spectra showed that the CF polymerization, F and Balmer emissions were stronger in the CF4/D2 plasma, by comparing with the CF4/H2 plasma. A thinner fluorocarbon thickness with a lower F/C ratio was found in the sample proceeded by the CF4/H2 plasma. The fluorocarbon thickness and gas phase concentration were not responsible for the increase of etch rate in the CF4/D2 plasma. The abstraction of H inside the SiN films by deuterium and hydrogen dissociation were considered to be important for the etching of the Si-H bond rich SiN films.

DOI： 10.1109/ISSM51728.2020.9377537

Web of Science

Scopus

無潤滑下及びベース油中におけるta-CNxコーティングのトライボロジー特性に及ぼすダングリングボンドと表面エネルギーの影響

宮地孝明, 中島悠也, 石川健治, Wooyoung Lee, 野老山貴行, 村島基之, 梅原徳次

年次大会 2020 巻 ( 0 ) 頁： S11314 2020年

Rapid thermal-cyclic atomic-layer etching of titanium nitride in CHF3/O2 downstream plasma 査読有り

Shinoda, K; Miyoshi, N; Kobayashi, H; Izawa, M; Ishikawa, K; Hori, M

JOURNAL OF PHYSICS D-APPLIED PHYSICS 52 巻 ( 47 ) 2019年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Physics D Applied Physics

Isotropic atomic-layer etching (ALE) of TiN-by using a plasma-assisted thermal-cyclic process with a 300-mm tool-was demonstrated. The process consists of exposure to a downstream CHF<inf>3</inf>/O<inf>2</inf> plasma (for surface modification) followed by infrared irradiation for thermal desorption of the modified surface. Etched amount of TiN per cycle saturated at around 0.6 nm/cycle with respect to both radical-exposure time and infrared-irradiation time. To examine the reaction mechanism of the cyclic etching, the surfaces of TiN samples after CHF<inf>3</inf>/O<inf>2</inf> plasma exposure were analyzed by in situ X-ray photoelectron spectroscopy (XPS). Self-limiting formation of the surface-modified layer, which was tentatively identified as an ammonium salt such as (NH<inf>4</inf>)<inf>x</inf>TiF<inf>y</inf>, was observed after radical exposure. It was confirmed by in situ XPS that the surface-modified layer was removed after thermal annealing at 110 °C. Isotropic ALE of TiN was thus demonstrated by using formation and desorption of ammonium salt in CHF<inf>3</inf>/O<inf>2</inf> downstream plasma, which was also used for isotropic ALE of Si<inf>3</inf>N<inf>4</inf>.

DOI： 10.1088/1361-6463/ab3cf3

Web of Science

Scopus

Simulation-aided design of very-high-frequency excited nitrogen plasma confinement using a shield plate 査読有り

Isobe, Y; Sakai, T; Suguro, K; Miyashita, N; Kondo, H; Ishikawa, K; Wilson, AF; Shimizu, N; Oda, O; Sekine, M; Hori, M

JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B 37 巻 ( 6 ) 2019年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Vacuum Science and Technology B Nanotechnology and Microelectronics

Nitrogen atoms are versatile for nitridation applications and do not lead to plasma-induced damage. Large-sized wafer processing demands a uniform supply of nitrogen atoms produced in a high-density very-high-frequency excited plasma of N<inf>2</inf> without ammonia. The confinement of plasma through the use of a plasma shield plate (PSP) allows the samples to be separated in a downstream chamber. Generation and transport of N atoms were computationally simulated, and the PSP designs were implemented by PSP parameterization. The supply of high-density N radicals to the sample stage was optimally designed with sufficiently small holes and thin PSP to satisfy an aspect ratio of thickness-to-hole-diameter of less than 2.5.

DOI： 10.1116/1.5114831

Web of Science

Scopus

Oxidative stress-dependent and -independent death of glioblastoma cells induced by non-thermal plasma-exposed solutions 査読有り Open Access

Tanaka, H; Mizuno, M; Katsumata, Y; Ishikawa, K; Kondo, H; Hashizume, H; Okazaki, Y; Toyokuni, S; Nakamura, K; Yoshikawa, N; Kajiyama, H; Kikkawa, F; Hori, M

SCIENTIFIC REPORTS 9 巻 ( 1 ) 頁： 13657 2019年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Scientific Reports

Non-thermal atmospheric pressure plasma has been widely used for preclinical studies in areas such as wound healing, blood coagulation, and cancer therapy. We previously developed plasma-activated medium (PAM) and plasma-activated Ringer’s lactate solutions (PAL) for cancer treatments. Many in vitro and in vivo experiments demonstrated that both PAM and PAL exhibit anti-tumor effects in several types of cancer cells such as ovarian, gastric, and pancreatic cancer cells as well as glioblastoma cells. However, interestingly, PAM induces more intracellular reactive oxygen species in glioblastoma cells than PAL. To investigate the differences in intracellular molecular mechanisms of the effects of PAM and PAL in glioblastoma cells, we measured gene expression levels of antioxidant genes such as CAT, SOD2, and GPX1. Microarray and quantitative real-time PCR analyses revealed that PAM elevated stress-inducible genes that induce apoptosis such as GADD45α signaling molecules. PAL suppressed genes downstream of the survival and proliferation signaling network such as YAP/TEAD signaling molecules. These data reveal that PAM and PAL induce apoptosis in glioblastoma cells by different intracellular molecular mechanisms.

DOI： 10.1038/s41598-019-50136-w

プラズマ活性化乳酸リンゲル点滴 (PAL) によるイネ幼苗の成長促進効果査読有り

橋爪博司, 水野寛子, 北野英己, 湯浅元気, 東野里江, 田中宏昌, 石川健治, 松本省吾, 榊原均, 前島正義, 仁川進, 水野正明, 堀勝

応用物理学会学術講演会講演予稿集 2019.2 巻 ( 0 ) 頁： 1895 - 1895 2019年9月

CH3Fの電子物性と解離査読有り

関根誠, 林俊雄, 堀勝, 石川健治

応用物理学会学術講演会講演予稿集 2019.2 巻 ( 0 ) 頁： 1837 - 1837 2019年9月

　前のページ - 次のページ　

<石川 健治>

論文 - 石川 健治

<石川　健治>

論文 - 石川　健治