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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：2 Percentile：52.07(Chemistry, Physical)Hashimoto, Shunsuke*; Yamaguchi, Satoshi*; Harada, Masashi*; Nakajima, Kenji; Kikuchi, Tatsuya*; Oishi, Kazuki*
Journal of Colloid and Interface Science, 638, p.475 - 486, 2023/05
Times Cited Count：2 Percentile：66.51(Chemistry, Physical)Recently, it has been reported that anomalous improvement in the thermal conductivity of nanofluid composed of base liquids and dispersed solid nanoparticles, compared to the theoretically predicted value calculated from the particle fraction. Generally, the thermal conductivity values of gases and liquids are dominated by the mean free path of the molecules during translational motion. Herein, we present solid evidence showing the possible contribution of the vibrational behavior of liquid molecules around nanoparticles to increasing these thermal conductivities.
and 
as interfering 
and 
threshold cuspsNakamura, Satoshi*; Hosaka, Atsushi; Yamaguchi, Yasuhiro
Physical Review D, 104(9), p.L091503_1 - L091503_8, 2021/11
Times Cited Count：15 Percentile：82.88(Astronomy & Astrophysics)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.
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：259 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.
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.
-ray Spectrometry of Environmental Samples Collected in FukushimaSaegusa, Jun; Yoda, Tomoyuki; Maeda, Satoshi; Okazaki, Tsutomu; Otani, Shuichi; Yamaguchi, Toshio; Kurita, Yoshiyuki; Hasumi, Atsushi; Yonezawa, Chushiro*; Takeishi, Minoru
Proceedings of 14th International Congress of the International Radiation Protection Association (IRPA-14), Vol.3 (Internet), p.1078 - 1085, 2017/11
After the nuclear accident at the Fukushima Daiichi Nuclear Power Plant in March 2011, the Japan Atomic Energy Agency has newly set up a laboratory for radioactivity analysis in Fukushima. At the laboratory, radioactivity concentrations of environmental samples such as soil, water, dust filter, plant, etc., approximately 1,000 samples in a month, are measured with high-resolution -ray spectrometry systems. The systems employ n-type HPGe detectors from Ortec. Since September 2012, characterization and upgrade of the systems have been performed aimed at enhancing reliability of analysis and convenience of customers. Resolving both systematic and technical issues, the laboratory has been accredited the ISO/IEC 17025 standard as a testing laboratory for radioactivity analysis.
-butadiene) rubbersYamaguchi, Daisuke; Yuasa, Takeshi*; Sone, Takuo*; Tominaga, Tetsuo*; Noda, Yohei*; Koizumi, Satoshi*; Hashimoto, Takeji*
Macromolecules, 50(19), p.7739 - 7759, 2017/10
Times Cited Count：14 Percentile：48.82(Polymer Science)We elucidated the spatial distribution of filler particles in cross-linked poly(styrene--butadiene) rubbers (SBR) developed under a typical fillers/rubbers compounding process as one of dissipative structures formed under a stress field imposed on the given system. The dispersion state of the fillers in SBR was clarified on the basis of hierarchical structures consisting of five structure levels. More specifically, it has the following characteristics depending on the specific interactions: Small, compact clusters build up compact mass-fractal structures, while large, loose clusters build up open mass-fractal structures.
Noda, Yohei*; Koizumi, Satoshi*; Masui, Tomomi*; Mashita, Ryo*; Kishimoto, Hiromichi*; Yamaguchi, Daisuke; Kumada, Takayuki; Takata, Shinichi; Oishi, Kazuki*; Suzuki, Junichi*
Journal of Applied Crystallography, 49(6), p.2036 - 2045, 2016/12
Times Cited Count：19 Percentile：78.58(Chemistry, Multidisciplinary)Masuda, Toshiyuki*; Arase, Junko*; Inagaki, Yusuke*; Kawahara, Masatoshi*; Yamaguchi, Kentaro*; Ohara, Takashi; Nakao, Akiko*; Momma, Hiroyuki*; Kwon, E.*; Setaka, Wataru*
Crystal Growth & Design, 16(8), p.4392 - 4401, 2016/08
Times Cited Count：27 Percentile：87.56(Chemistry, Multidisciplinary)
Fe(, n)
Fe reaction with a linearly polarized -ray beamHayakawa, Takehito; Shizuma, Toshiyuki; Miyamoto, Shuji*; Amano, Sho*; Takemoto, Akinori*; Yamaguchi, Masashi*; Horikawa, Ken*; Akimune, Hidetoshi*; Chiba, Satoshi*; Ogata, Kazuyuki*; et al.
Physical Review C, 93(4), p.044313_1 - 044313_4, 2016/04
Times Cited Count：7 Percentile：49.18(Physics, Nuclear)We have measured the azimuthal anisotropy of neutrons emitted from the Fe(, n)Fe reaction with a linearly polarized ray beam generated by laser Compton scattering at NewSUBARU. Neutron yields at the polar angle of 90 have been measured as a function of the azimuthal angle 
between the detector and the linear polarization plane of the ray beam. The azimuthal anisotropy of neutrons measured at seven angles has been well reproduced using a theoretically predicted function of 
+ 
cos(2).
Zhao, Y.; Yoshimura, Kimio; Shishitani, Hideyuki*; Yamaguchi, Susumu*; Tanaka, Hirohisa*; Koizumi, Satoshi*; Szekely, N.*; Radulescu, A.*; Richter, D.*; Maekawa, Yasunari
Soft Matter, 12(5), p.1567 - 1578, 2016/02
Times Cited Count：27 Percentile：79.79(Chemistry, Physical)Yamamoto, Seiichi*; Toshito, Toshiyuki*; Komori, Masataka*; Morishita, Yuki*; Okumura, Satoshi*; Yamaguchi, Mitsutaka; Saito, Yuichi; Kawachi, Naoki; Fujimaki, Shu
Annals of Nuclear Medicine, 29(3), p.268 - 275, 2015/04
Times Cited Count：21 Percentile：66.09(Radiology, Nuclear Medicine & Medical Imaging)
L. irradiated by raysKitano, Sayaka*; Miyagi, Atsuko*; Ono, Yutaka; Hase, Yoshihiro; Narumi, Issey*; Yamaguchi, Masatoshi*; Uchimiya, Hirofumi*; Kawai, Maki*
Metabolomics, 11(1), p.134 - 142, 2015/02
Times Cited Count：8 Percentile：25.41(Endocrinology & Metabolism)Zhao, Y.; Koizumi, Satoshi; Yamaguchi, Daisuke; Kondo, Tetsuo*
European Physical Journal E, 37(12), p.129_1 - 129_12, 2014/12
Times Cited Count：7 Percentile：30.85(Chemistry, Physical)Kurisaka, Kenichi; Sakai, Takaaki; Yamano, Hidemasa; Fujita, Satoshi*; Minagawa, Keisuke*; Yamaguchi, Akira*; Takata, Takashi*
Nuclear Engineering and Design, 269, p.268 - 280, 2014/04
Times Cited Count：5 Percentile：36.96(Nuclear Science & Technology)This paper describes a study to develop the level-1 probabilistic safety assessment (PSA) method that is applicable to the Japan Sodium-cooled Fast Reactor (JSFR). This study aims to provide a new evaluation method of (1) passive safety architectures related to internal events and (2) an advanced seismic isolation system related to a seismic event as a representative external event in Japan. Regarding the internal events evaluation, a quantitative analysis on the frequency of the core damage caused by reactor shutdown failure was conducted. A failure in passive reactor shutdown was taken into account in the event tree model. The failure rate of sodium-cooled fast reactor (SFR) specific components was evaluated based on the operating experience in existing SFRs by applying the Hierarchical Bayesian Method, which can consider a plant-to-plant variability. By conducting an uncertainty analysis, it was found that the assumption about the correlation of the probability parameters between the main and backup reactor shutdown systems is sensitive to the mean value of the frequency of the core damage caused by reactor shutdown failure. As for the seismic event evaluation, seismic response analysis and sensitivity analysis of a seismic isolation system were carried out. As a result, it was confirmed that nonlinear properties of rubber bearings have influence on response of the building and inner equipment.
Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki; Otani, Kazunori*; Hiyama, Yoshinori*; et al.
JAEA-Review 2013-041, 115 Pages, 2014/01
JAEA-Review-2013-041.pdf:19.01MB
Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2012, from 1st April 2012 to 31st March 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.
Taguchi, Tomitsugu; Miyazaki, Toshiki*; Iikubo, Satoshi*; Yamaguchi, Kenji
Materials Science & Engineering C, 34, p.29 - 34, 2014/01
Times Cited Count：9 Percentile：20.94(Materials Science, Biomaterials)SiC nanotubes can become candidate reinforcement materials for dental and orthopedic implants due to their light weight and excellent mechanical properties. However, it has not been reported about the development of bioactive SiC materials. In this study, hydroxyapatites were found to on SiC nanotubes treated with NaOH and subsequently HCl solution after soaking in simulated body fluid. On the other hand, hydroxyapatites did not deposit on as-received SiC nanotubes, the SiC nanotubes with NH
OH solution treatment and SiC bulk materials with NaOH and subsequently HCl solution treatment. Therefore, we succeeded in the development of bioactive SiC nanotubes by downsizing SiC materials to nanometer size and treating with NaOH and subsequently HCl solutions for the first time.
-FeSi
film on Si(100)Yamaguchi, Kenji; Hamamoto, Satoshi*; Hojo, Kiichi
Physica Status Solidi (C), 10(12), p.1699 - 1703, 2013/12
Times Cited Count：0 Percentile：0.01(Nanoscience & Nanotechnology)Effect of substrate treatment conditions, deposition temperature and deposition rate on the crystallinity of -FeSi films formed on Si substrate was investigated. The substrates were treated with Ne
ion beams at room temperature and then annealed at 1073 K prior to film fabrication by means of ion beam sputter deposition (IBSD) method. Combinations of experimental parameters which promote the epitaxial relationship of -FeSi (100) // Si (100) were defined. Complicated dependence of these experimental parameters on the film structure indicated that careful optimization of substrate treatment conditions and deposition parameters would enable to obtain -FeSi films with excellent crystalline properties.
Minagawa, Keisuke*; Fujita, Satoshi*; Yamaguchi, Akira*; Takata, Takashi*; Kurisaka, Kenichi
Nihon Kikai Gakkai Rombunshu, C, 79(804), p.2684 - 2693, 2013/08
