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Sekio, Yoshihiro; Sakaguchi, Norihito*
Materials Transactions, 60(5), p.678 - 687, 2019/05
Times Cited Count：5 Percentile：29.02(Materials Science, Multidisciplinary)The quantitative evaluation of vacancy migration energies in high nickel model alloy was conducted by analyzing the void denuded zone (VDZ) width formed near grain boundaries under neutron and electron irradiation. The microstructures of Fe-15Cr-xNi (x=15, 20, 25, 30 mass%) alloys that were neutron irradiated at 749 K and electron irradiated at 576 K-824 K were examined. The VDZ widths increased with increasing Ni content in both irradiation experiments, which implies an increase of the vacancy mobility. The vacancy migration energies were estimated from the temperature dependence of the VDZ widths, and the energies were 1.09, 0.97, 0.90, and 0.77 eV for the alloys containing 15, 20, 25, and 30 mass% Ni, respectively. From the obtained energies, the effective vacancy diffusivity and excess vacancy concentration were estimated using the analytical equation of the VDZ width, which quantitatively confirmed the increase of the vacancy mobility with increasing Ni content.
Shibata, Yuichi*; Imaizumi, Mitsuru*; Sato, Shinichiro; Oshima, Takeshi; Ooka, Sachiyo*; Takamoto, Tatsuya*
Proceedings of 11th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications (RASEDA-11) (Internet), p.65 - 68, 2015/11
Radiation response is one of the important properties for space solar cells. It should be well understood so as to accurately predict their degradation in orbit and also to improve their radiation tolerance. Recently, a phenomenon, recovery from the radiation degradation by light soaking, on inverted metamorphic (IMM) triple-junction (3J) solar cells was found out. In this work, the light soaking annealing effects on electron irradiated IMM 3J solar cells are reported. IMM 3J solar cells irradiated with 1 MeV electrons with the fluence of 3
10
e
/cm
showed the recovery of open-circuit voltage, Voc, up to 43 mV after light (AM0, 1 sun) soaking of 3 hours. The increment of the electroluminescence intensity for InGaP in the IMM 3J cells due to the light soaking suggests that the Voc recovery occurs in InGaP top-cell rather than GaAs middle-cell or InGaAs bottom-cell.
Miyazawa, Yu*; Ikegami, Masashi*; Miyasaka, Tsutomu*; Oshima, Takeshi; Imaizumi, Mitsuru*; Hirose, Kazuyuki*
Proceedings of 42nd IEEE Photovoltaic Specialists Conference (PVSC-42) (CD-ROM), p.1178 - 1181, 2015/06
Yamashita, Shinichi*; Iwamatsu, Kazuhiro; Maehashi, Yuki*; Taguchi, Mitsumasa; Hata, Kuniki; Muroya, Yusa*; Katsumura, Yosuke*
RSC Advances (Internet), 5(33), p.25877 - 25886, 2015/02
Times Cited Count：12 Percentile：38(Chemistry, Multidisciplinary)Pulse radiolysis experiments were carried out to observe transient absorptions of reaction intermediates produced in N
O
and Ar-saturated aqueous solutions containing 0.9-900 mM NaBr. The most important species among the reaction intermediates are BrOH 
and Br , which commonly have absorption peaks around 360 nm. The experimental results were compared with the results of simulation based on a spur diffusion model. Each of several complicated sequential radiation-induced chemical reactions was carefully considered, optimizing its rate constant within a range of reported values. All the experimental results were able to be universally reproduced by the simulation, assuming a reaction not yet reported, 2BrOH 
Br + 2OH, with a rate constant of 3.8 10
M
s, which is significant only within 10 micro-s for rather high bromide concentrations (
10 mM). Primary 
values, which are yields after sufficient diffusion from the spur to the perimeter region during 100 ns, of major water decomposition products, as well as of the reaction intermediates, were calculated for NO and Ar-saturated conditions as a function of NaBr concentration.
Son, N. T.*; Umeda, Takahide*; Isoya, Junichi*; Gali, A.*; Bockstedte, M.*; Magnusson, B.*; Ellison, A.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; et al.
Physica B; Condensed Matter, 376-377, p.334 - 337, 2006/04
Times Cited Count：3 Percentile：17.99(Physics, Condensed Matter)no abstracts in English
Matsuura, Hideharu*; Kagamihara, So*; Ito, Yuji*; Oshima, Takeshi; Ito, Hisayoshi
Physica B; Condensed Matter, 376-377, p.342 - 345, 2006/04
Times Cited Count：8 Percentile：38.44(Physics, Condensed Matter)no abstracts in English
Matsuura, Hideharu*; Kagamihara, So*; Ito, Yuji*; Oshima, Takeshi; Ito, Hisayoshi
Microelectronic Engineering, 83(1), p.17 - 19, 2006/01
Times Cited Count：3 Percentile：24.47(Engineering, Electrical & Electronic)no abstracts in English
Pensl, G.*; Ciobanu, F.*; Frank, T.*; Kirmse, D.*; Krieger, M.*; Reshanov, S.*; Schmid, F.*; Weidner, M.*; Oshima, Takeshi; Ito, Hisayoshi; et al.
Microelectronic Engineering, 83(1), p.146 - 149, 2006/01
Times Cited Count：15 Percentile：59.32(Engineering, Electrical & Electronic)no abstracts in English
4/
5 center in 4H-SiCUmeda, Takahide*; Son, N. T.*; Isoya, Junichi*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; Janz
n, E.*
Materials Science Forum, 527-529, p.543 - 546, 2006/00
no abstracts in English
Son, N. T.*; Umeda, Takahide*; Isoya, Junichi*; Gali, A.*; Bockstedte, M.*; Magnusson, B.*; Ellison, A.*; Morishita, Norio; Oshima, Takeshi; Ito, Hisayoshi; et al.
Materials Science Forum, 527-529, p.527 - 530, 2006/00
no abstracts in English
Kawasuso, Atsuo; Yoshikawa, Masahito; Ito, Hisayoshi; Chiba, Toshinobu*; Higuchi, Takatoshi*; Betsuyaku, Kiyoshi*; Redmann, F.*; Krause-Rehberg, R.*
Physical Review B, 72(4), p.045204_1 - 045204_6, 2005/07
Times Cited Count：16 Percentile：55.78(Materials Science, Multidisciplinary)Two-dimensional angular correlation of annihilation radiation (2D-ACAR) and coincidence Doppler broadening (CDB) of annihilation radiation measurements have been performed on electron-irradiated n-type 3C SiC in which isolated silicon vacancies are responsible for positron trapping. After irradiation, the intensity of CDB spectrum increased and decreased in low and high momentum regions, respectively. These fetures were explained by the theoretical calculation considering silicon vacancies. The center region of 2D-ACAR spectra became isotropic after iradiation, while the overall anisotropies extending within the Jones zone were conserved suggesting that isolated silicon vacancies have the tetrahedral symmetry as expected from the previous electron spin resonance study.
Katakai, Akio; Tamada, Masao; Nagamoto, Hiroyuki*; Miyagawa, Hiroshi*
Nihon Ion Kokan Gakkai-Shi, 16(2), p.122 - 126, 2005/05
A chelating fiber containing an amidoxime group as a chelate-forming group was prepared by radiation-induced cograft polymerization of acrylonitrile and methacrylic acid and subsequent conversion of the produced cyano group into the amidoxime group. The effect of repeated use of monomers for radiation-induced graft copolymerization on the composition of the graft chain and its adsorption capacity for metal ions was determined. The degree of cografting decreased by as low as 10% at the fourth cycle of cografting, compared with an initial degree of cografting of 170%, because the amount of homopolymer formed in cografting was negligibly small at 0.15 g/L of the monomer solution. The repeated use of monomers did not affect the amidoxime group density and the adsorption capacities of zinc and cadmium ions, resulting in the cost reduction of the preparation of the chelating fiber.
SiCKawasuso, Atsuo; Chiba, Toshinobu*; Higuchi, Takatoshi*
Physical Review B, 71(19), p.193204_1 - 193204_4, 2005/05
Times Cited Count：15 Percentile：53.97(Materials Science, Multidisciplinary)Electron-positron momentum distributions associated with vacancy defects in 6H SiC after irradiation with 2 MeV electrons and annealing at 1000
have been studied using angular correlation of annihilation radiation (ACAR) measurements. It was confirmed that the above vacancy defects have dangling bonds along the c-axis and the rotational symmetry around it. The first principles calculation suggests that the vacancy defects are attributable to either carbon-vacancy-carbon-antisites complexes or silicon-vacancy-nitrogen pairs, while isolated carbon vacancies, silicon vacancies and nearest neighbor divacancies are ruled out.
Kinoshita, Akimasa*; Iwami, Motohiro*; Kobayashi, Kenichi*; Nakano, Itsuo*; Tanaka, Reisaburo*; Kamiya, Tomihiro; Oi, Akihiko; Oshima, Takeshi; Fukushima, Yasutaka*
Nuclear Instruments and Methods in Physics Research A, 541(1-2), p.213 - 220, 2005/04
Times Cited Count：27 Percentile：84.86(Instruments & Instrumentation)no abstracts in English
crystalsAbe, Kenichiro*; Miyoshi, Yoshihiro*; Ashida, Atsushi*; Wakita, Kazuki*; Oshima, Takeshi; Morishita, Norio; Kamiya, Tomihiro; Watase, Seiji*; Izaki, Masanobu*
Japanese Journal of Applied Physics, 44(1B), p.718 - 721, 2005/01
Times Cited Count：1 Percentile：4.7(Physics, Applied)no abstracts in English
Jo, Akinori*; Okada, Kenji*; Tamada, Masao; Kume, Tamikazu; Sugo, Takanobu; Tazaki, Masato*
Chemistry for the Protection of the Environment 4; Environmental Science Research, Vol. 59, p.49 - 62, 2005/00
Bifunctional cation exchange fibers were synthesized by co-grafting of chloromethylstylene and styrene. on polyethylene-coated polypropylene fibers. The grafted fibers were fictionalized by Arbuzov reaction, suffonation, and acid hydrolysis. Batchwise evaluation of metal ion selectivity clarified that the bifunctional fiber exhibited cooperative recognition of metal ions by both functional groups. The bifunctional fiber took up Pb(II) more rapidly than the monofunctional phosphoric acid fiber and commercial resin adsorbent. Column-mode experiment revealed that flow rate was independent of break through profiles of Pb(II) up to flow rate of 900 h in space velocity.
Ekins-Daukes, N. J.*; Arafune, Koji*; Lee, H. S.*; Sasaki, Takuo*; Yamaguchi, Masafumi*; Khan, A.*; Takamoto, Tatsuya*; Agui, Takaaki*; Kamimura, Kunio*; Kaneiwa, Minoru*; et al.
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.683 - 686, 2005/00
no abstracts in English
Nakabayashi, Masakazu*; Oyama, Hidenori*; Hanano, N.*; Hirao, Toshio; Simoen, E.*; Claeys, C.*
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.183 - 186, 2004/10
no abstracts in English
filmsOkada, Hiroshi*; Natsume, Satoshi*; Wakahara, Akihiro*; Yoshida, Akira*; Oshima, Takeshi; Kamiya, Tomihiro
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.147 - 150, 2004/10
no abstracts in English
Ekins-Daukes, N. J.*; Lee, H. S.*; Sasaki, Takuo*; Yamaguchi, Masafumi*; Khan, A.*; Takamoto, Tatsuya*; Agui, Takaaki*; Kamimura, Kunio*; Kaneiwa, Minoru*; Imaizumi, Mitsuru*; et al.
Proceedings of the 6th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-6), p.87 - 91, 2004/10
no abstracts in English
