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Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Takagi, Yasuhiko*; Nakamura, Tomoki*; Hiroi, Takahiro*; Matsuoka, Moe*; et al.
Nature Astronomy (Internet), 5(3), p.246 - 250, 2021/03
Times Cited Count：43 Percentile：96.93(Astronomy & Astrophysics)Here we report observations of Ryugu's subsurface material by the Near-Infrared Spectrometer (NIRS3) on the Hayabusa2 spacecraft. Reflectance spectra of excavated material exhibit a hydroxyl (OH) absorption feature that is slightly stronger and peak-shifted compared with that observed for the surface, indicating that space weathering and/or radiative heating have caused subtle spectral changes in the uppermost surface. However, the strength and shape of the OH feature still suggests that the subsurface material experienced heating above 300 
C, similar to the surface. In contrast, thermophysical modeling indicates that radiative heating does not increase the temperature above 200 C at the estimated excavation depth of 1 m, even if the semimajor axis is reduced to 0.344 au. This supports the hypothesis that primary thermal alteration occurred due to radiogenic and/or impact heating on Ryugu's parent body.
Myagmarjav, O.; Iwatsuki, Jin; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Ioka, Ikuo; Kubo, Shinji; Nomura, Mikihiro*; Yamaki, Tetsuya*; Sawada, Shinichi*; et al.
International Journal of Hydrogen Energy, 44(35), p.19141 - 19152, 2019/07
Times Cited Count：16 Percentile：49.6(Chemistry, Physical)Chikazawa, Yoshitaka; Konomura, Mamoru; Mizuno, Tomoyasu; Mito, Makoto*; Tanji, Mikio*
Nuclear Technology, 154(2), p.142 - 154, 2006/05
Times Cited Count：2 Percentile：17.18(Nuclear Science & Technology)Small fast reactors have a potential to be utilized as a power source applicable to diversified social needs and reduce capital risks. In remote sites such as Alaska and Hawaii, power sources without refueling whose capacities are lower than 50 MW-electric are required, because fuel transfer cost is expensive in such sites. In the case of power sources for developing countries, capacities are required in a range 50-300 MW-electric and proliferation resistance must be enhanced. A solution of a power plant without refueling is a fast reactor plant with a very long life core and proliferation resistance in such a plant is supposed to be tough. We have studied concepts of small fast reactor with various attractiveness such as economical competitiveness, reactor safety and very long lived core. In this study, a design concept of a small lead-bismuth cooled reactor, which pursues long operating cycle and inherent safety has been studied. The core is nitride fueled two regions homogeneous core cooled by natural circulated lead-bismuth eutectic. The burnup reactivity is kept 0.93 %dk/k and without refueling 30 years operation with 7.8 GWd/t average burnup. Since lead-bismuth eutectic is chemically inert in lead-bismuth-water contact, a simple tank type design with the steam generator in the reactor vessel is adopted eliminating an intermediate circuit system. The transient analysis shows the reactor has possible capability to keep the reactor system and fuel integrity in UTOP and ULOHS events. The target construction cost for remote sites is achieved by the first plant with 50 MW-electric capacity. The economical target of power sources for developing countries cities is also achieved in the condition of 150 MW electric power regarding series effect.
Hayafune, Hiroki; Enuma, Yasuhiro; Mizuno, Tomoyasu; Soman, Yoshindo; Konomura, Mamoru; Mito, Makoto*; Tanji, Mikio*
Roshia Kosokuro Kokusai Kaigi, 0 Pages, 2003/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Kuriyama, Masaaki; ; Araki, Masanori; ; Hanada, Masaya; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; *; Kunieda, Shunsuke; et al.
Fusion Engineering and Design, 26, p.445 - 453, 1995/00
Times Cited Count：43 Percentile：95.65(Nuclear Science & Technology)no abstracts in English
Matsuoka, Mamoru; Araki, Masanori; Mizuno, Makoto
Fusion Technology, 26, p.1296 - 1303, 1994/12
no abstracts in English
Inoue, Takashi; Miyamoto, Kenji; Mizuno, Makoto; Okumura, Yoshikazu; Ohara, Yoshihiro; G.D.Ackerman*; C.F.Chan*; W.S.Cooper*; J.W.Kwan*; M.C.Vella*
15th IEEE/NPSS Symp. on Fusion Engineering,Vol. 1, 0, p.474 - 477, 1994/00
no abstracts in English
Inoue, Takashi; Hanada, Masaya; *; Mizuno, Makoto; Ohara, Yoshihiro; Okumura, Yoshikazu; Suzuki, Yasuo*; Tanaka, Masanobu*; Watanabe, Kazuhiro
Plasma Devices and Operations, 3, p.211 - 222, 1994/00
no abstracts in English
Okumura, Yoshikazu; Araki, Masanori; Hanada, Masaya; Inoue, Takashi; Kunieda, Shunsuke; Kuriyama, Masaaki; Matsuoka, Mamoru; Mizuno, Makoto; Ohara, Yoshihiro; Tanaka, Masanobu*; et al.
Production and Neutralization of Negative Ions and Beams; AIP Conference Proceedings 287, p.839 - 848, 1994/00
no abstracts in English
Mizuno, Makoto; Ohara, Yoshihiro; Watanabe, Kazuhiro; *
JAERI-M 93-214, 13 Pages, 1993/10
no abstracts in English
beam in an electrostatic acceleratorWatanabe, Kazuhiro; Hanada, Masaya; Inoue, Takashi; *; Miyamoto, Kenji*; Mizuno, Makoto; Ohara, Yoshihiro; Okumura, Yoshikazu
EP-93-48, p.11 - 19, 1993/08
no abstracts in English
Kuriyama, Masaaki; Kunieda, Shunsuke; Matsuoka, Mamoru; Mizuno, Makoto; Ohara, Yoshihiro; Ohara, Hiroshi; Mogaki, Kazuhiko
JAERI-M 93-059, 13 Pages, 1993/03
no abstracts in English
Mizuno, Makoto; Ohara, Yoshihiro
Review of Scientific Instruments, 64(2), p.477 - 480, 1993/02
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)no abstracts in English
Kuriyama, Masaaki; ; Araki, Masanori; ; Hanada, Masaya; Inoue, Takashi; Kawai, Mikito; Kazawa, Minoru; *; Kunieda, Shunsuke; et al.
15th IEEE/NPSS Symp. on Fusion Engineering,Vol. 1, 0, p.470 - 473, 1993/00
no abstracts in English
ion source for neutral beam injectorsOkumura, Yoshikazu; Hanada, Masaya; Inoue, Takashi; *; Miyamoto, Kenji; Mizuno, Makoto; Ohara, Yoshihiro; Tanaka, Masanobu*; Watanabe, Kazuhiro
Dai-4-Kai Ryushisen No Sentanteki Oyo Gijutsu Ni Kansuru Shimpojiumu, p.51 - 54, 1993/00
no abstracts in English
Mizuno, Makoto; Hanada, Masaya; Inoue, Takashi; Ohara, Yoshihiro; Okumura, Yoshikazu; Tanaka, Shigeru; Watanabe, Kazuhiro; Asahara, Masaharu*; *; *; et al.
Fusion Engineering and Design, 23, p.49 - 55, 1993/00
Times Cited Count：3 Percentile：38.1(Nuclear Science & Technology)no abstracts in English
Kuriyama, Masaaki; Ohara, Yoshihiro; ; ; Hanada, Masaya; Inoue, Takashi; *; *; Ito, Takao; Kawai, Mikito; et al.
Fusion Technology 1992, Vol.1, p.564 - 568, 1993/00
no abstracts in English
Watanabe, Kazuhiro; Hanada, Masaya; Inoue, Takashi; *; Mizuno, Makoto; Ohara, Yoshihiro; Okumura, Yoshikazu; Suzuki, Yasuo*; Tanaka, Hideki*; Tanaka, Masanobu*
Proc. of 14th Int. Conf. on Plasma Physics and Controlled Nuclear Fusion Research, p.371 - 378, 1993/00
no abstracts in English
ion source for the JT-60U negative-ion-based neutral beam injectorOkumura, Yoshikazu; Hanada, Masaya; Inoue, Takashi; Kuriyama, Masaaki; Maeno, Shuichi*; Matsuoka, Mamoru; Miyamoto, Kenji; Mizuno, Makoto; Ohara, Yoshihiro; Suzuki, Satoshi; et al.
Proceedings of 15th IEEE/NPSS Symposium on Fusion Engineering, p.466 - 469, 1993/00
no abstracts in English
Watanabe, Kazuhiro; Mizuno, Makoto; Ohara, Yoshihiro; Tanaka, Masanobu*; *; *; *
Journal of Applied Physics, 72(9), p.3949 - 3956, 1992/11
Times Cited Count：32 Percentile：81.19(Physics, Applied)no abstracts in English
