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(001)Tsai, Y. H.*; Kobata, Masaaki; Fukuda, Tatsuo; Tanida, Hajime; Kobayashi, Toru; Yamashita, Yoshiyuki*
Applied Physics Letters, 124(11), p.112105_1 - 112105_5, 2024/03
Times Cited Count：0Lee, M.-S.*; Kawasaki, Takuro; Yamashita, Takayuki*; Harjo, S.; Hyun, Y.-T.*; Jeong, Y.*; Jun, T.-S.*
Scientific Reports (Internet), 12(1), p.3719_1 - 3719_10, 2022/03
Times Cited Count：6 Percentile：63.54(Multidisciplinary Sciences)Aoki, Hiroyuki; Liu, Y.*; Yamashita, Takashi*
Scientific Reports (Internet), 11(1), p.22711_1 - 22711_9, 2021/11
Times Cited Count：9 Percentile：60.44(Multidisciplinary Sciences)Onodera, Naoyuki; Idomura, Yasuhiro; Ali, Y.*; Yamashita, Susumu; Shimokawabe, Takashi*; Aoki, Takayuki*
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.210 - 215, 2020/10
This paper presents a GPU-based Poisson solver on a block-based adaptive mesh refinement (block-AMR) framework. The block-AMR method is essential for GPU computation and efficient description of the nuclear reactor. In this paper, we successfully implement a conjugate gradient method with a state-of-the-art multi-grid preconditioner (MG-CG) on the block-AMR framework. GPU kernel performance was measured on the GPU-based supercomputer TSUBAME3.0. The bandwidth of a vector-vector sum, a matrix-vector product, and a dot product in the CG kernel gave good performance at about 60% of the peak performance. In the MG kernel, the smoothers in a three-stage V-cycle MG method are implemented using a mixed precision RB-SOR method, which also gave good performance. For a large-scale Poisson problem with 
cells, the developed MG-CG method reduced the number of iterations to less than 30% and achieved 
2.5 speedup compared with the original preconditioned CG method.
Ohgama, Kazuya; Ando, Yoko; Yamaguchi, Mika; Ikuta, Yuko; Shinohara, Nobuo; Murakami, Hiroyuki; Yamashita, Kiyonobu; Uesaka, Mitsuru*; Demachi, Kazuyuki*; Komiyama, Ryoichi*; et al.
JAEA-Review 2013-004, 76 Pages, 2013/05
JAEA-Review-2013-004.pdf:13.53MB
JAEA together with the Japan Nuclear Human Resource Development Network (JN-HRD Net), the University of Tokyo (UT) and the Japan Atomic Industrial Forum (JAIF) cohosted the IAEA-Nuclear Energy Management School in Tokai Village, aiming that Japan will be the center of nuclear HRD in the Asian region. In the school, not only lectures by IAEA experts, but also lectures by Japanese experts and technical visits were included for foreign participants. The school contributed to the internationalization of Japanese young professionals, development of nuclear human resource of other countries, and enhancement of cooperation between IAEA and Japan. Additionally, collaborative relationship within JN-HRD Net was strengthened by the school. In this report, findings obtained during the preparatory work and the school period are reported for future international nuclear HRD activities in Japan.
Hata, Kuniki; Lin, M.; Katsumura, Yosuke*; Muroya, Yusa*; Fu, H. Y.*; Yamashita, Shinichi; Nakagawa, Hidehiko*
Journal of Radiation Research, 52(1), p.15 - 23, 2011/01
Times Cited Count：21 Percentile：61.13(Biology)Yan, Y.*; Lin, M.; Katsumura, Yosuke*; Muroya, Yusa*; Yamashita, Shinichi; Hata, Kuniki; Meesungnoen, J.*; Jay-Gerin, J.-P.*
Canadian Journal of Chemistry, 88(10), p.1026 - 1033, 2010/10
Times Cited Count：1 Percentile：7.11(Chemistry, Multidisciplinary)The optical absorption spectra of the solvated electron (e
) in sub- and super-critical methanol are measured by both electron pulse radiolysis and laser photolysis techniques, at temperatures in the range 220-270 
C. Over the density range studied (
0.45-0.59 g/cm
), the position of the absorption maximum (
) of e is found to shift only slightly to the red with decreasing density. In agreement with our previous work in water, at a fixed pressure, decreases monotonically with increasing temperature in passing through the phase transition at 
(239.5 C). By contrast, at a fixed density, exhibits a minimum as the solvent passes above the critical point into the supercritical state. These behaviors are discussed in terms of microscopic arguments based on the changes that occur in the methanol properties and methanol structure in the sub- and supercritical regimes.
Lin, M.; Fu, H.*; Lampre, I.*; De Waele, V.*; Muroya, Yusa*; Yan, Y.*; Yamashita, Shinichi; Katsumura, Yosuke; Mostafavi, M.*
Journal of Physical Chemistry A, 113(44), p.12193 - 12198, 2009/10
Times Cited Count：7 Percentile：22.38(Chemistry, Physical)With a revisit of the absorption coefficient of the solvated electron in propane-1,2,3-triol, the temperature dependent behavior of the absorption spectrum of solvated electron was studied from room temperature to 573 K by pulse radiolysis techniques. The change in the absorption spectrum of solvated electron in propane-1,2,3-triol observed by cooling down from a high temperature to 333 K is compared with that occurring during the electron solvation process at 333 K. The effect of the specific molecular structure of propane-1,2,3-triol compared to other alcohols is discussed.
Xu, Y.*; Tagawa, Akihiro; Fujiki, Kazunari*; Ueda, Masashi; Yamashita, Takuya
Proceedings of 17th International Conference on Nuclear Engineering (ICONE-17) (CD-ROM), 9 Pages, 2009/07
In-service inspection is carried out to confirm the integrity of the main components of "MONJU". The ambient temperature during the inspection is 200 C and the irradiation field is 10 Gy/hr. A Periodic Permanent Magnet (PPM) structure has been used for electromagnetic acoustic transducer (EMAT). The PPM structure is the structure of putting in order alternately the S pole and N pole laterally magnetized magnets. A Halbach magnet structure is the structure which sandwiched the longitudinally magnetized magnets between each magnet of PPM structure. Thereby, magnetic flux density is improved 1.4 times. Moreover, it also checked aiming at 4 times as many improvement in detection sensitivity as this by a new signal processing method. The high temperature characteristic and high temperature durability of Halbach type EMAT in 200 hours which corresponds the twice of inspection time under the 200 C inspection environment are reported.
Shibata, Keiichiro*; Maki, Koichi*; Inoue, Takashi*; Hanada, Masaya; Okumura, Yoshikazu; Yamashita, Y.*
Fusion Engineering and Design, 51-52, p.357 - 362, 2000/11
Times Cited Count：1 Percentile：12.08(Nuclear Science & Technology)no abstracts in English
Inoue, Takashi; *; *; Yamashita, Y.*
Fusion Technology 1996, 0, p.1799 - 1802, 1996/00
no abstracts in English
Ohara, Yoshihiro; Tanaka, Shigeru; Akiba, Masato; Araki, Masanori; Fujisawa, Noboru; Hanada, Masaya; Inoue, Takashi; *; Mizuno, Makoto; Okumura, Yoshikazu; et al.
JAERI-M 91-052, 176 Pages, 1991/03
no abstracts in English
Inoue, Takashi; Akiba, Masato; Araki, Masanori; Hanada, Masaya; *; Mizuno, Makoto; Okumura, Yoshikazu; Ohara, Yoshihiro; Seki, Masahiro; Tanaka, Shigeru; et al.
Fusion Engineering and Design, 18, p.369 - 376, 1991/00
Times Cited Count：3 Percentile：40.77(Nuclear Science & Technology)no abstracts in English
Mizuno, Makoto; Dairaku, Masayuki; Ohara, Yoshihiro; *; Tanaka, Shigeru; *; Watanabe, Kazuhiro; Yamashita, Y.*;
IEEE 13th Symp. on Fusion Engineering, Vol. 1, p.574 - 577, 1989/00
no abstracts in English
Lin, M.; Katsumura, Yosuke; Fu, H.*; Yan, Y.*; Muroya, Yusa*; Yamashita, Shinichi
no journal, ,
The temperature dependent behaviors of the absorption spectrum of solvated electron in glycerol were studied from room temperature to 250 C by pulse radiolysis techniques. With a revisit of the absorption coefficient, the time dependent yield of solvated electron in glycerol, from picosecond to microsecond, was also investigated.
Yokobori, Shinichi*; Yang, Y.*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Kobayashi, Kensei*; Hashimoto, Hirofumi*; Kawai, Hideyuki*; Mita, Hajime*; Narumi, Issei; Okudaira, Kyoko*; et al.
no journal, ,
no abstracts in English
Yokobori, Shinichi*; Yang, Y.*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Hashimoto, Hirofumi*; Yamashita, Masamichi*; Yano, Hajime*; Okudaira, Kyoko*; Yoshimura, Yoshitaka*; Narumi, Issei; et al.
no journal, ,
no abstracts in English
Yokobori, Shinichi*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Yang, Y.*; Fushimi, Hidehiko*; Hashimoto, Hirofumi*; Yamashita, Masamichi*; Yano, Hajime*; Okudaira, Kyoko*; Hayashi, Nobuhiro*; et al.
no journal, ,
no abstracts in English
Lin, M.; Katsumura, Yosuke; Muroya, Yusa*; Fu, H.*; Yamashita, Shinichi; Yan, Y.*
no journal, ,
In the present work, we have investigated the optical absorption spectral shift of 4,4'-bipyridyl radical at elevated temperature and supercritical water. The results show that the spectral shift is mainly due to the change of water properties, especially the dielectric constant. Local density effect on the spectral shift has been also observed.
Hata, Kuniki; Katsumura, Yosuke; Lin, M.; Muroya, Yusa*; Yamashita, Shinichi; Fu, H. Y.*; Kudo, Hisaaki*; Nakagawa, Keiichi*; Nakagawa, Hidehiko*
no journal, ,
In order to investigate the reaction mechanism of edaravone (3-methyl-1-phenyl-2-pyrazolin- 5-one) with OH, the reactivity of edaravone derivatives which have different substituent from edaravone was observed by pulse radiolysis system. From the experiments, OH-adduct radical formed by the addition of OH to phenyl group has been identified as a main intermediate.
