Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yoshimune, Wataru*; Higuchi, Yuki*; Kato, Akihiko*; Hibi, Shogo*; Yamaguchi, Satoshi*; Matsumoto, Yoshihiro*; Hayashida, Hirotoshi*; Nozaki, Hiroshi*; Shinohara, Takenao; Kato, Satoru*
ACS Energy Letters (Internet), 8(8), p.3485 - 3487, 2023/08
Times Cited Count：3 Percentile：66.84(Chemistry, Physical)Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count：6 Percentile：49.29(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
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：44 Percentile：97.1(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.
Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.
Science, 364(6437), p.272 - 275, 2019/04
Times Cited Count：262 Percentile：99.73(Multidisciplinary Sciences)The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.
pellets by 28 GHz microwave irradiationAkashi, Masatoshi; Matsumoto, Taku; Kato, Masato
Transactions of the American Nuclear Society, 118, p.1391 - 1394, 2018/06
In this study, CeO pellet sintering by irradiating microwave at a frequency of 28 GHz was carried out to investigate the effect of particle diameter of raw powder on the density of sintered pellet. The highest bulk density is 94.2 %T.D. under the condition of 30 min holding at 1473 K. The bulk density decreases with increasing the particle diameter of used raw powder. On the other hand, all of the apparent density of sintered pellet is more than 93.5 %T.D.. The difference between the bulk density and the apparent density is caused by the difference of open porosity for each sample pellet. It seems that the high density sintered pellets with porous structure are obtained because sample pellet is heated internally and uniformly in microwave sintering.
Matsumoto, Toshinori; Sato, Masatoshi; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 6 Pages, 2017/07
Sato, Masatoshi; Matsumoto, Toshinori; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of 8th European Review Meeting on Severe Accident Research (ERMSAR 2017) (Internet), 12 Pages, 2017/05
Kato, Masato; Watanabe, Masashi; Matsumoto, Taku; Hirooka, Shun; Akashi, Masatoshi
Journal of Nuclear Materials, 487, p.424 - 432, 2017/04
Times Cited Count：12 Percentile：75.2(Materials Science, Multidisciplinary)Oxygen potential of (U,Pu)O was evaluated based on defect chemistry using an updated experimental data set. The relationship between oxygen partial pressure and deviation 
in (U,Pu)O was analyzed, and equilibrium constants of defect formation were determined as functions of Pu content and temperature. Brouwer's diagrams were constructed using the determined equilibrium constants, and a relational equation to determine O/M ratio was derived as functions of O/M ratio, Pu content and temperature. In addition, relationship between oxygen potential and oxygen diffusion coefficients were described.
Sr)
Rh
Sn
Cheung, Y. W.*; Hu, Y. J.*; Goh, S. K.*; Kaneko, Koji; Tsutsui, Satoshi; Logg, P. W.*; Grosche, F. M.*; Kanagawa, Hibiki*; Tanioku, Yasuaki*; Imai, Masaki*; et al.
Journal of Physics; Conference Series, 807(3), p.032002_1 - 032002_4, 2017/04
Times Cited Count：5 Percentile：83.41(Physics, Condensed Matter)Sato, Masatoshi; Matsumoto, Toshinori; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 10 Pages, 2016/11
Li(p,xn) reaction for incident energies up to 200 MeVMatsumoto, Yuiki*; Watanabe, Yukinobu*; Kunieda, Satoshi; Iwamoto, Osamu
JAEA-Conf 2015-003, p.191 - 196, 2016/03
Neutron emission from the Li(p,n)Be reaction can be divided into two components: a mono-energetic component for the transition to the ground and the 1st excited states and a continuum component formed by Li breakup processes. For the former, we have obtained the differential cross sections by interpolation based on Legendre fitting of available experimental data up to 45 MeV and apply DWBA calculations above 45 MeV. Next, we have applied the CCONE code to DDX calculations of the continuum component, and adjusted pre-equilibrium model parameters to reproduce experimental data well. Finally, both the results are merged and then the evaluated DDX data are completed.
Mikami, Satoshi; Matsuda, Norihiro; Ando, Masaki; Kinase, Sakae; Kitano, Mitsuaki; Kawase, Keiichi; Matsumoto, Shinichiro; Yamamoto, Hideaki; Saito, Kimiaki
Radioisotopes, 64(9), p.589 - 607, 2015/09
This article presents the features of regional distributions and temporal changes in air dose rate and radionuclide deposition densities in Fukushima on the basis of analyses on large-scale environmental monitoring results using diverse methods. The continuity of decontamination effects is discussed according to repeated monitoring data after the decontamination model project. Further, some examples are shown on the projection of air dose rates together with the ecological half lives for different land uses.
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.
-orbital symmetry of the ground state in Yb compounds by linear dichroism in core-level photoemissionMori, Takeo*; Kitayama, Satoshi*; Kanai, Yuina*; Naimen, Sho*; Fujiwara, Hidenori*; Higashiya, Atsushi*; Tamasaku, Kenji*; Tanaka, Arata*; Terashima, Kensei*; Imada, Shin*; et al.
Journal of the Physical Society of Japan, 83(12), p.123702_1 - 123702_5, 2014/12
Times Cited Count：16 Percentile：68.37(Physics, Multidisciplinary)We show that the strongly correlated 4-orbital symmetry of the ground state is revealed by linear dichroism in core-level photoemission spectra, as we have discovered for YbRhSi and YbCuSi. Theoretical analysis shows us that the linear dichroism reflects the anisotropic charge distributions resulting from a crystalline electric field. We have successfully determined the ground-state 4 symmetry for both compounds from the polarization-dependent angle resolved core-level spectra at a temperature well below the first excitation energy. The excited-state symmetry is also probed by temperature dependence of the linear dichroism where the high measurement temperatures are on the order of the crystal-field-splitting energies.
Tsukasaki, Yoshikazu*; Miyazaki, Naoyuki*; Matsumoto, Atsushi; Nagae, Shigenori*; Yonemura, Shigenobu*; Tanoue, Takuji*; Iwasaki, Kenji*; Takeichi, Masatoshi*
Proceedings of the National Academy of Sciences of the United States of America, 111(45), p.16011 - 16016, 2014/11
Times Cited Count：38 Percentile：63.49(Multidisciplinary Sciences)
+ 
Li reactions using the continuum-discretized coupled-channels methodIchinkhorloo, D.*; Matsumoto, Takuma*; Hirabayashi, Yoshiharu*; Kato, Kiyoshi*; Chiba, Satoshi
Journal of Nuclear Science and Technology, 48(11), p.1357 - 1360, 2011/10
Times Cited Count：6 Percentile：44.16(Nuclear Science & Technology)The + Li reactions are important not only from the basic interest of the system but also from the application point of view. In this work, we study Li breakup reactions of incident neutron energies 11.5, 14.1 and 18.0 MeV by applying an 
+ 
cluster model to 
Li and using the continuum-discretized coupled-channels approach. At the present energy, our calculation gives almost good agreement with experimental data.
Sano, Yuichi; Katsurai, Kiyomichi; Washiya, Tadahiro; Koizumi, Tsutomu; Matsumoto, Satoshi*
Proceedings of 19th International Conference on Nuclear Engineering (ICONE-19) (CD-ROM), 7 Pages, 2011/10
Japan Atomic Energy Agency has been studying rotary drum type continuous dissolver for FBR spent fuel dissolution. For estimating the fuel dissolution behavior under several operational conditions in this dissolver, we have been developed the simulation code, PLUM, which mainly consists of 3 modules for calculating chemical reaction, mass transfer and thermal balance in the rotary drum type continuous dissolver.
Ogata, Kazuyuki*; Matsumoto, Takuma*; Hashimoto, Shintaro; Minomo, Kosho*; Egami, Tomoaki*; Iseri, Yasunori*; Kono, Michio*; Chiba, Satoshi; Bertulani, C. A.*; Shimizu, Yoshifumi*; et al.
Journal of Physics; Conference Series, 312, p.082008_1 - 082008_10, 2011/09
Times Cited Count：1 Percentile：47.48(Physics, Nuclear)Recent studies on breakup reactions with the continuum-discretized coupled channels method are reviewed. The topics covered are: four-body breakup processes for He induced reaction, dynamical relativistic effects on coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple- reaction rate) and new approach to inclusive breakup processes.
Co
film by magnetic Compton scatteringAgui, Akane; Matsumoto, Sayaka*; Sakurai, Hiroshi*; Tsuji, Naruki*; Homma, Satoshi*; Sakurai, Yoshiharu*; Ito, Masayoshi*
Applied Physics Express, 4(8), p.083002_1 - 083002_3, 2011/08
Times Cited Count：14 Percentile：51.42(Physics, Applied)We have succeeded in measuring microscopic magnetic hysteresis loop of amorphous TbCo film. Spin selective magnetic hysteresis (SSMH) loop was measured by magnetic Compton scattering at synchrotron radiation facility SPring-8 and obtaining orbital selective magnetic hysteresis (OSMH) loop was firstly obtained by combining with result of macroscopic magnetic hysteresis loop.
Li(
)Li
reactions with the microscopic coupled-channels methodMatsumoto, Takuma*; Ichinkhorloo, D.*; Hirabayashi, Yoshiharu*; Kato, Kiyoshi*; Chiba, Satoshi
Physical Review C, 83(6), p.064611_1 - 064611_6, 2011/06
Times Cited Count：21 Percentile：75.45(Physics, Nuclear)We investigate Li()Li
reactions by using the continuum-discretized coupled-channels method with the complex Jeukenne-Lejeune-Mahaux effective nucleon-nucleon interaction. In this study, the Li nucleus is described by a d + cluster model. The calculated elastic cross sections for incident energies between 7.47 and 24.0 MeV are in good agreement with experimental data. Furthermore, we show that the neutron spectra for Li breakup states measured at selected angular points and incident energies can be also reproduced systematically.
