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Bendo, A.*; Matsuda, Kenji*; Nishimura, Katsuhiko*; Nunomura, Norio*; Tsuchiya, Taiki*; Lee, S.*; Marioara, C. D.*; Tsuru, Tomohito; Yamaguchi, Masatake; Shimizu, Kazuyuki*; et al.
Materials Science and Technology, 36(15), p.1621 - 1627, 2020/09
Times Cited Count:8 Percentile:47.13(Materials Science, Multidisciplinary)Metastable phases in aluminum alloys are the primary nano-scale precipitates which have the biggest contribution to the increase in the tangible mechanical properties. The continuous increase in hardness in the 7xxx aluminum alloys is associated with the phase transformation from clusters or GP-zones to the metastable phase. The transformation which is structural and compositional should occur following the path of the lowest activation energy. This work is an attempt to gain insight into how the structural transformation may occur based on the shortest route of diffusion for the eventual structure to result in that of phase. However, for the compositional transformation to occur, the proposed mechanism may not stand, since it is a prerequisite for the atoms to be at very precise positions in the aluminum lattice, at the very beginning of structural transformation, which may completely differ from that of the GP-zones atomic arrangements.
Matsuda, Kenji*; Yasumoto, Toru*; Bendo, A.*; Tsuchiya, Taiki*; Lee, S.*; Nishimura, Katsuhiko*; Nunomura, Norio*; Marioara, C. D.*; Lervik, A.*; Holmestad, R.*; et al.
Materials Transactions, 60(8), p.1688 - 1696, 2019/08
Times Cited Count:14 Percentile:63.04(Materials Science, Multidisciplinary)no abstracts in English
Nishimura, Katsuhiko*; Matsuda, Kenji*; Lee, S.*; Nunomura, Norio*; Shimano, Tomoki*; Bendo, A.*; Watanabe, Katsumi*; Tsuchiya, Taiki*; Namiki, Takahiro*; Toda, Hiroyuki*; et al.
Journal of Alloys and Compounds, 774, p.405 - 409, 2019/02
Times Cited Count:3 Percentile:17.96(Chemistry, Physical)Toda, Hiroyuki*; Yamaguchi, Masatake; Matsuda, Kenji*; Shimizu, Kazuyuki*; Hirayama, Kyosuke*; Su, H.*; Fujihara, Hiro*; Ebihara, Kenichi; Itakura, Mitsuhiro; Tsuru, Tomohito; et al.
Tetsu To Hagane, 105(2), p.240 - 253, 2019/02
Times Cited Count:0 Percentile:0(Metallurgy & Metallurgical Engineering)no abstracts in English
Tanaka, Taiki*; Narikiyo, Yoshihiro*; Morita, Kosuke*; Fujita, Kunihiro*; Kaji, Daiya*; Morimoto, Koji*; Yamaki, Sayaka*; Wakabayashi, Yasuo*; Tanaka, Kengo*; Takeyama, Mirei*; et al.
Journal of the Physical Society of Japan, 87(1), p.014201_1 - 014201_9, 2018/01
Times Cited Count:18 Percentile:74.47(Physics, Multidisciplinary)Excitation functions of quasielastic scattering cross sections for the Ca + Pb, Ti + Pb, and Ca + Cm reactions were successfully measured by using the gas-filled recoil-ion separator GARIS. Fusion barrier distributions were extracted from these data, and compared with the coupled-channels calculations. It was found that the peak energies of the barrier distributions for the Ca + Pb and Ti + Pb systems coincide with those of the 2n evaporation channel cross sections for the systems, while that of the Ca + Cm is located slightly below the 4n evaporation ones. This results provide us helpful information to predict the optimum beam energy to synthesize superheavy nuclei.
Kaji, Daiya*; Morita, Kosuke*; Morimoto, Koji*; Haba, Hiromitsu*; Asai, Masato; Fujita, Kunihiro*; Gan, Z.*; Geissel, H.*; Hasebe, Hiroo*; Hofmann, S.*; et al.
Journal of the Physical Society of Japan, 86(3), p.034201_1 - 034201_7, 2017/03
Times Cited Count:28 Percentile:81.43(Physics, Multidisciplinary)The fusion reaction of Ca + Cm Lv was studied using the gas-filled recoil-ion separator GARIS at RIKEN. A total of seven and spontaneous-fission decay chains were observed, which would originate from the reaction products of the element 116, Lv and Lv. Decay properties observed in the chains are in good agreement with the previously published ones. However, one of the chains showed a discrepancy, indicating the new spontaneous-fission branch in Cn or the production of the new isotope Lv.
Yamaguchi, Taiki; Kawano, Yasunori; Fujieda, Hirobumi; Kurihara, Kenichi; Sugihara, Masayoshi*; Kusama, Yoshinori
Plasma Physics and Controlled Fusion, 50(4), p.045004_1 - 045004_15, 2008/04
The poloidal polarimeter will be installed in the International Thermonuclear Experimental Reactor (ITER) to measure the safety factor profile. The number of viewing chords is restricted to about 15 channels. Therefore optimization of the viewing chord arrangement is necessary to diagnose the accurate safety factor profile. In this study, we studied the optimum viewing chord arrangement for the equilibria of ITER operation scenarios using the equilibrium reconstruction. For the burning phase of inductive scenario, the error of the safety factor on the magnetic axis was 35% if the viewing chords are not arranged in the peripheral region. It was improved to 3% by arranging the viewing chord of the upper port to peripheral region. This arrangement was used for the reconstruction of the burning phase in the noninductive scenario and of the phase of the plasma current 3.5 MA in the inductive operation scenario. As the result, the accuracy does not decrease drastically.
Yamaguchi, Taiki; Kawano, Yasunori; Fujieda, Hirobumi; Kurihara, Kenichi; Sugihara, Masayoshi*; Kusama, Yoshinori
Plasma Physics and Controlled Fusion, 50(4), p.045004_1 - 045004_15, 2008/04
Times Cited Count:10 Percentile:38.22(Physics, Fluids & Plasmas)We have studied the viewing chord arrangement of the poloidal polarimeter in the International Thermonuclear Experimental Reactor (ITER). We have optimized the viewing chord arrangement based on the evaluation using a magnetohydrodynamic equilibrium reconstruction code. This reconstruction code has been developed in this study. We have successfully optimized viewing chord arrangements for three equilibria of the ITER operation scenario. The accuracy of the central safety factor within 3% has been achieved in each case. Furthermore, the viewing chord arrangement, which is optimized for the inductive operation scenario II at the start of the burn phase (S2-SOB), has been applied for other equilibria. As the result, the accuracy has not deteriorated drastically compared with the accuracy which is evaluated using the optimized arrangement for each equilibrium. The viewing chord arrangement for S2-SOB is proposed as the most promising candidate of the ITER poloidal polarimeter.
Yamaguchi, Taiki; Kawano, Yasunori; Kusama, Yoshinori
JAEA-Research 2007-078, 43 Pages, 2008/03
The poloidal polarimeter will be installed in the International Thermonuclear Experimental Reactor (ITER) to measure the profile of the toroidal current (safety factor) in the plasma core region. For the optimization of the viewing chord arrangement of the ITER poloidal polarimeter, we studied the sensitivity of the viewing chord arrangement on the current profile. We proposed the new method for the sensitivity study, in which the Faraday rotation angle due to the toroidal current only is used as the sensitive index. As the result, we could find the viewing chords which are sensitive to the central current density, the finite beta effect and the ratio of the central current density and the maximum current density in case of the hollow current profile. Next, we proposed the viewing chord arrangements which are sensitive to the current profiles of ITER operation scenarios.
Yamaguchi, Taiki; Kawano, Yasunori; Kusama, Yoshinori
Plasma and Fusion Research (Internet), 2, p.S1112_1 - S1112_4, 2007/11
no abstracts in English
Yamaguchi, Taiki; Kawano, Yasunori; Kusama, Yoshinori
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Kawano, Yasunori; Yamaguchi, Taiki; Kusama, Yoshinori; Hiramatsu, Miho*; Kiyohara, Motosuke*
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Watanabe, Kiyomasa*; Suzuki, Yasuhiro*; Yamaguchi, Taiki; Narihara, Kazumichi*; Tanaka, Kenji*; Tokuzawa, Tokihiko*; Yamada, Ichihiro*; Sakakibara, Satoru*; Morisaki, Tomohiro*; Nakajima, Noriyoshi*; et al.
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Watanabe, Kiyomasa*; Yamaguchi, Taiki; Narushima, Yoshiro*; Sakakibara, Satoru*; Suzuki, Yasuhiro*; Nakamura, Yuji*; Funaba, Hisamichi*; Nakajima, Noriyoshi*; LHD Experimental Group*
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Yamaguchi, Taiki; Kawano, Yasunori; Fujieda, Hirobumi; Kurihara, Kenichi; Sugihara, Masayoshi*; Kusama, Yoshinori
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no abstracts in English