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Your search keyword '"Giichiro Uchida"' showing total 5 results
Start Over Author "Giichiro Uchida" Journal applied physics express
5 results on '"Giichiro Uchida"'

1. Development of nanostructured Ge/C anodes with a multistacking layer fabricated via Ar high-pressure sputtering for high-capacity Li+-ion batteries

Author

Tomoki Omae, Teruya Yamada, Daiki Fujikake, Takahiro Kozawa, and Giichiro Uchida

Subjects
low temperature plasma process, Li ion battery, Ge, Physics, QC1-999
Abstract

To realize high-capacity Ge anodes for next-generation Li ^+ -ion batteries, a multilayer anode with a C(top)/Ge(middle)/C(bottom) structure was developed, where nanostructured amorphous Ge (a-Ge) and amorphous-like carbon films with a grain size of 10–20 nm were deposited sequentially by high-pressure Ar sputtering at 500 mTorr. Compared with the a-Ge anode, the C(top)/a-Ge(middle)/C(bottom) multistacking layer anode showed improved capacity degradation for repeated lithiation/delithiation reactions and achieved a high capacity of 910 mAh g ^−1 with no capacity fading after 90 cycles at a C-rate of 0.1.

Published
2024
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2. Two-dimensional concentration distribution of reactive oxygen species transported through a tissue phantom by atmospheric-pressure plasma-jet irradiation

Author

Shota Kusumegi, Giichiro Uchida, Kazunori Koga, Toshiyuki Kawasaki, Tomohiro Sakanoshita, Masaharu Shiratani, Akihiro Sato, Takuya Tsurumaru, and Akihiro Kudo

Subjects
010302 applied physics, chemistry.chemical_classification, Jet (fluid), Reactive oxygen species, General Engineering, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Atmospheric-pressure plasma, 01 natural sciences, Oxygen, 010305 fluids & plasmas, chemistry, Reagent, 0103 physical sciences, Irradiation, Helium, Tissue phantom
Abstract

The two-dimensional concentration distribution of reactive oxygen species (ROSs) transported through an agarose-film tissue phantom by atmospheric-pressure plasma-jet irradiation is visualized using a KI-starch gel reagent. Oxygen addition to helium enhances ROS transportation through the film. A radial ROS distribution pattern at the plasma-irradiated film surface changes into a doughnut-shaped pattern after passing through the film. The ROS transportation speed is 0.14–0.2 mm/min. We suggest that there are two types of ROS transportation pathways in the plasma-irradiated film: linear and circular. The majority of ROSs are transported through the circular pathway. ROS concentration distributions changed markedly with irradiation distance. Diffusive ROS transportation due to a concentration gradient is negligible in plasma-irradiated films.

Published
2016

3. Impacts of Amplitude Modulation of RF Discharge Voltage on the Growth of Nanoparticles in Reactive Plasmas

Author

Hiroshi Miyata, Kazunori Koga, Naho Itagaki, Kunihiro Kamataki, Giichiro Uchida, and Masaharu Shiratani

Subjects
Radical fluxes, Reactive plasmas, Plasma fluctuations, Chemistry, Radical, Small size, General Engineering, Nucleation, Analytical chemistry, General Physics and Astronomy, Nanoparticle, Plasma, Amplitude modulation, Flux (metallurgy), Chemical physics, RF discharge, Rate of increase, Nanoparticles, Electric discharges, Rf discharge, Voltage
Abstract

We have investigated the effects of plasma fluctuation on the growth of nanoparticles in capacitively-coupled rf discharges with amplitude modulation (AM). Nanoparticles grow more slowly for higher AM levels, which causes the density of nanoparticles to increase by 100% and their size to decrease by 23%. The increase in the number of radicals for nucleation and nanoparticles by AM is thought to cause a decrease in the radical flux for a nanoparticle because the rate of increase in the number of radicals is smaller than that of nanoparticles. Therefore, this causes the generation of a large amount of nanoparticles with small sizes.

Published
2011

4. Highly Conducting and Very Thin ZnO:Al Films with ZnO Buffer Layer Fabricated by Solid Phase Crystallization from Amorphous Phase

Author

Kazunori Koga, Kenta Nakahara, Masaharu Shiratani, Kazunari Kuwahara, Daisuke Yamashita, Naho Itagaki, and Giichiro Uchida

Subjects
Materials science, Oxide, Novel methods, General Physics and Astronomy, Nanotechnology, Crystal growth, Buffer (optical fiber), law.invention, Crystallinity, chemistry.chemical_compound, Optical transmittance, law, Sputtering, Electrical resistivity and conductivity, Zinc oxide, Crystallinities, ZnO films, Buffer layers, Crystallization, ZnO buffer layer, Amorphous phase, General Engineering, Conductive films, AZO films, Zno: ai, Nitrogen atom, Chemical engineering, chemistry, ZnO, Conventional sputtering, Wavelength ranges, Solid-phase crystallization, Amorphous films, Layer (electronics)
Abstract

We propose a novel method of oxide crystal growth via atomic-additive mediated amorphization. By utilizing this method, solid-phase crystallization (SPC) of ZnO from amorphous phase has been successfully demonstrated via nitrogen atom mediation. The resultant SPC-ZnO films are highly orientated and the crystallinity is higher than that of the films prepared by conventional sputtering. By using the SPC-ZnO as a buffer layer, the resistivity of ZnO:Al (AZO) films is drastically decreased. 20-nm-thick AZO films with a resistivity of 5 × 10^ Ω cm and an optical transmittance higher than 80% in a wide wavelength range of 400-2500 nm have been obtained.

Published
2010

5. Two-dimensional concentration distribution of reactive oxygen species transported through a tissue phantom by atmospheric-pressure plasma-jet irradiation.

Author

Toshiyuki Kawasaki, Akihiro Sato, Shota Kusumegi, Akihiro Kudo, Tomohiro Sakanoshita, Takuya Tsurumaru, Giichiro Uchida, Kazunori Koga, and Masaharu Shiratani

Abstract

The two-dimensional concentration distribution of reactive oxygen species (ROSs) transported through an agarose-film tissue phantom by atmospheric-pressure plasma-jet irradiation is visualized using a KI-starch gel reagent. Oxygen addition to helium enhances ROS transportation through the film. A radial ROS distribution pattern at the plasma-irradiated film surface changes into a doughnut-shaped pattern after passing through the film. The ROS transportation speed is 0.14–0.2 mm/min. We suggest that there are two types of ROS transportation pathways in the plasma-irradiated film: linear and circular. The majority of ROSs are transported through the circular pathway. ROS concentration distributions changed markedly with irradiation distance. Diffusive ROS transportation due to a concentration gradient is negligible in plasma-irradiated films. [ABSTRACT FROM AUTHOR]

Published
2016
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