Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
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.
Si studied by angle-resolved photoelectron spectroscopy; Elucidating the contribution of U 5
states in URu
SiFujimori, Shinichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Matsumoto, Yuji*; Yamamoto, Etsuji; Tateiwa, Naoyuki; et al.
Physical Review B, 96(12), p.125117_1 - 125117_9, 2017/09
Times Cited Count：10 Percentile：45.87(Materials Science, Multidisciplinary)Terada, Atsuhiko; Matsumoto, Masaaki*; Sugiyama, Hitoshi*; Kamiji, Yu; Hino, Ryutaro
Proceedings of 6th International Conference on Hydrogen Safety (ICHS 2015) (CD-ROM), 11 Pages, 2015/10
To improve the safety performance of the Nuclear Power Station, especially on the hydrogen safety under severe accident conditions, a simulation code system has been developed to analyze hydrogen behavior including diffusion, combustion, explosion and structural integrity evaluation. This developing system consists of CFD and FEM tools in order to support various hydrogen user groups consisting of students, researchers and engineers. Preliminary analytical results obtained with above mentioned tools, especially with open source codes including buoyancy turbulent model and condensation model, agreed well with the existing test data.
Terada, Atsuhiko; Matsumoto, Masaaki*; Sugiyama, Hitoshi*; Kamiji, Yu; Kadowaki, Satoshi*; Hino, Ryutaro
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05
In the Fukushima Daiichi Nuclear Power Station (NPS) accident, hydrogen was generated by oxidation reaction of the cladding and water etc, then leaked into the NPS building, and finally led to occurrence of hydrogen explosion in the building. This resulted in serious damage to the environment. To improve the safety performance of the NPS, especially on the hydrogen safety under severe accident conditions, a simulation code system has been developed to analyze hydrogen behaviors including diffusion, combustion, explosion and structural integrity evaluation. This developing system consists of CFD and FEM tools in order to support various hydrogen user groups of students, researchers and engineers. Preliminary calculated results obtained with above mentioned tools, damage of piping induced by hydrogen combustion, agreed well with existing test data.
Sakanaka, Shogo*; Akemoto, Mitsuo*; Aoto, Tomohiro*; Arakawa, Dai*; Asaoka, Seiji*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.2338 - 2340, 2010/05
Future synchrotron light source using a 5-GeV energy recovery linac (ERL) is under proposal by our Japanese collaboration team, and we are conducting R&D efforts for that. We are developing high-brightness DC photocathode guns, two types of cryomodules for both injector and main superconducting (SC) linacs, and 1.3 GHz high CW-power RF sources. We are also constructing the Compact ERL (cERL) for demonstrating the recirculation of low-emittance, high-current beams using above-mentioned critical technologies.
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
S
Okane, Tetsuo; Fujimori, Shinichi; Mamiya, Kazutoshi; Okamoto, Jun; Muramatsu, Yasuji; Fujimori, Atsushi; Suzuki, Hiroyuki*; Matsumoto, Takehiko*; Furubayashi, Takao*; Isobe, Masaaki*; et al.
Journal of Magnetism and Magnetic Materials, 272-276(Suppl.), p.e297 - e298, 2004/05
Times Cited Count：5 Percentile：29.77(Materials Science, Multidisciplinary)The electronic structure of spinel-type chalcogenide CuIrS, which exhibits a metal-insulator transition (MIT) as a function of temperature, has been studied by photoemission spectroscopy (PES). Below the transition temperature 
, the valence-band PES spectra indicate a gap formation, while the overall valence-band structure is shifted to the higher binding-energy side. The line shape of the Ir 4
core-level PES spectra shows a dramatic change across , which may be associated with the variation of the Ir 5
electron states.
Suyama, Kenya; Onoue, Masaaki*; Matsumoto, Hideki*; Sasahara, Akihiro*; Katakura, Junichi
JAERI-Data/Code 2000-036, 35 Pages, 2000/11
JAERI-Data-Code-2000-036.pdf:1.19MB
no abstracts in English
Okubo, Hiroo*; Nakajima, Kengo*; Matsumoto, Masaaki*
JNC TJ1400 2005-015, 388 Pages, 1999/02
JNC-TJ1400-2005-015.pdf:27.73MB
no abstracts in English
Muramatsu, Ken; ; Matsumoto, Kiyoshi; ; Kondo, Masaaki; *
The 3rd JSME/ASME Joint Int. Conf. on Nuclear Engineering, Vol. 3, 0, p.1333 - 1340, 1995/00
no abstracts in English
Suzuki, Yuji; Shibata, Masahiro; Makino, Hitoshi; Umeki, Hiroyuki; Hioki, Kazumasa; Matsumoto, Masaaki*; Okubo, Hiroo*
no journal, ,
no abstracts in English
Si studied by ARPESFujimori, Shinichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Matsumoto, Yuji*; Yamamoto, Etsuji; Tateiwa, Naoyuki; et al.
no journal, ,
no abstracts in English
Matsumoto, Masaaki*; Ashida, Takaki*; Kawai, Masaki*; Terada, Atsuhiko; Hino, Ryutaro
no journal, ,
In the Fukushima Daiichi Nuclear Power Station (NPS) accident, hydrogen was generated by oxidation reaction of the cladding and water etc, then leaked into the NPS building, and finally led to occurrence of hydrogen explosion in the building. This resulted in serious damage to the environment. To improve the safety performance of the NPS, especially on the hydrogen safety under severe accident conditions, a simulation code system has been developed to analyze hydrogen behaviors including diffusion, combustion. This developing system consists of open source code in order to support various hydrogen user groups of students, researchers and engineers. Preliminary calculated results obtained with above mentioned tools, agreed well with ISP47 TOSQAN test-data.
Si studied by ARPESFujimori, Shinichi; Kobata, Masaaki; Takeda, Yukiharu; Okane, Tetsuo; Saito, Yuji; Fujimori, Atsushi; Yamagami, Hiroshi; Matsumoto, Yuji*; Yamamoto, Etsuji; Tateiwa, Naoyuki; et al.
no journal, ,
ThRuSi is an isostructural compound of the heavy fermion superconductor URuSi which shows the hidden order transition. Since ThRuSi does not have 5f electrons, it is a good reference material to understand the contribution of U 5f electrons in the electronic structure of URuSi. In the present study, we have revealed the band structure and Fermi surface of ThRuSi by angle resolved photoelectron spectroscopy (ARPES) using soft X-rays (hn = 600-800 eV). The experimentally obtained band structure and Fermi surface are compared with those of URuSi as well as the result of the band structure calculation. We have found that the states in the vicinity of EF are very different in ThRuSi and URuSi, suggesting that U 5f electrons form itinerant bands in URuSi. The details of the electronic structure of ThRuSi and the contributions from U 5f electrons in the band structure and Fermi surface of URuSi are discussed.
Ir
Sn
Kaneko, Koji; Matsuda, Masaaki*; Tsutsui, Satoshi*; Goh, S. K.*; Matsumoto, Takuya*; Imai, Masaki*; Yoshimura, Kazuyoshi*
no journal, ,
no abstracts in English
Terada, Atsuhiko; Kamiji, Yu; Hino, Ryutaro; Matsumoto, Masaaki*; Sugiyama, Hitoshi*; Kadowaki, Satoshi*
no journal, ,
To further improve the safety performance of the Nuclear Power Station, especially on the hydrogen safety under severe accident conditions, a simulation code system has been developed to analyze hydrogen behaviors including diffusion, combustion, explosion and structural integrity evaluation. Preliminary calculated results obtained with above mentioned tools agreed well with ISP47 TOSQAN test data of OECD/NEA project.
Terada, Atsuhiko; Kamiji, Yu; Hino, Ryutaro; Sugiyama, Hitoshi*; Matsumoto, Masaaki*; Kadowaki, Satoshi*
no journal, ,
no abstracts in English
Matsumoto, Ayumu; Oba, Hironori; Toshimitsu, Masaaki; Akaoka, Katsuaki; Wakaida, Ikuo
no journal, ,
Matsumoto, Ayumu; Oba, Hironori; Toshimitsu, Masaaki; Akaoka, Katsuaki; Wakaida, Ikuo
no journal, ,
no abstracts in English
Wakaida, Ikuo; Oba, Hironori; Oba, Masaki; Matsumoto, Ayumu; Ruas, A.; Toshimitsu, Masaaki; Akaoka, Katsuaki; Miyabe, Masabumi
no journal, ,
For the decommissioning of "Fukushima Daiichi Nuclear Power Station", Optical Fiber based LIBS probe is constructed, and under water condition, we have successfully observed some specific spectra from the simulated sample of molten debris made by sintered oxide of Zr and U. For the use of more longer optical fiber, long-pulse laser with the pulse duration about 100 ns will be introduced to compensate the delivery power loss and/or to enhance the emission signal to be about several times by the time integration of emission signal. As for the signal enhancement technique, microwave assisted LIBS technique coupled with simple antenna for the combination use with fiber LIBS will be under developing, and about ten times enhancement was observed under the atmosphere condition. For the application to the liquid phase sample, especially for the analysis of the polluted cooling water, the thin-sheet liquid jets will be also introduced as the convenience and high sensitive monitoring for dissolved elements of nuclear fuel debris.
