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Tamii, Atsushi*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.
European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09
no abstracts in English
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:30 Percentile:96.87(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.
Ogawa, Yusuke*; Suzuki, Satoru*; Taniguchi, Naoki; Kawasaki, Manabu*; Suzuki, Hiroyuki*; Takahashi, Rieko*
Materials and Corrosion, 72(1-2), p.52 - 66, 2021/01
Times Cited Count:2 Percentile:13.1(Materials Science, Multidisciplinary)Cast steel is one of the promising alternative to forged steel that is the current reference material for carbon steel overpack. In this study, the full-scale cast steel overpack was produced experimentally and the distribution of casting defects were investigated. The corrosion test regarding corrosion rate and stress corrosion cracking (SCC) susceptibility were also conducted using samples taken from the full-scale cast steel overpack and the corrosion resistance of cast steel was compared with that of forged steel. From above two corrosion tests, it can be said that the corrosion resistance of cast steel is mostly the same as that of forged steel.
Higuchi, Yuki*; Setoyama, Daigo*; Isegawa, Kazuhisa; Tsuchikawa, Yusuke; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Nagai, Yasutaka*
Physical Chemistry Chemical Physics, 23(2), p.1062 - 1071, 2021/01
Times Cited Count:5 Percentile:54.2(Chemistry, Physical)This study is the first report on liquid water and ice imaging conducted at a pulsed spallation neutron source facility. Neutron imaging can be utilised to visualise the water distribution inside polymer electrolyte fuel cells (PEFCs). Particularly, energy-resolved neutron imaging is a methodology capable of distinguishing between liquid water and ice, and is effective for investigating ice formation in PEFCs operating in a subfreezing environment. The distinction principle is based on the fact that the cross sections of liquid water and ice differ from each other at low neutron energies. In order to quantitatively observe transient freezing and thawing phenomena in a multiphase mixture (gas/liquid/solid) within real PEFCs with high spatial resolution, a pulsed neutron beam with both high intensity and wide energy range is most appropriate. In the validation study of the present work, we used water sealed in narrow capillary tubes to simulate the flow channels of a PEFC, and a pulsed neutron beam was applied to distinguish ice, liquid water and super-cooled water, and to clarify freezing and thawing phenomena of the water within the capillary tubes. Moreover, we have enabled the observation of liquid water/ice distributions in a large field of view (300 mm 300 mm) by manufacturing a sub-zero environment chamber that can be cooled down to -30C, as a step towards visualisation of full-size fuel cells.
Ishikawa, Takatsugu*; Fujimura, Hisako*; Fukasawa, Hiroshi*; Hashimoto, Ryo*; He, Q.*; Honda, Yuki*; Hosaka, Atsushi; Iwata, Takahiro*; Kaida, Shun*; Kasagi, Jirota*; et al.
Physical Review C, 101(5), p.052201_1 - 052201_6, 2020/05
Kurihara, Momo*; Yasutaka, Tetsuo*; Aono, Tatsuo*; Ashikawa, Nobuo*; Ebina, Hiroyuki*; Iijima, Takeshi*; Ishimaru, Kei*; Kanai, Ramon*; Karube, Jinichi*; Konnai, Yae*; et al.
Journal of Radioanalytical and Nuclear Chemistry, 322(2), p.477 - 485, 2019/11
Times Cited Count:2 Percentile:21.95(Chemistry, Analytical)We assessed the repeatability and reproducibility of methods for determining low dissolved radiocesium concentrations in freshwater in Fukushima. Twenty-one laboratories pre-concentrated three of 10 L samples by five different pre-concentration methods (prussian-blue-impregnated filter cartridges, coprecipitation with ammonium phosphomolybdate, evaporation, solid-phase extraction disks, and ion-exchange resin columns), and activity of radiocesium was measured. The z-scores for all of the Cs results were within 2, indicating that the methods were accurate. The relative standard deviations (RSDs) indicating the variability in the results from different laboratories were larger than the RSDs indicating the variability in the results from each separate laboratory.
Motokawa, Ryuhei; Taniguchi, Tatsuo*; Kumada, Takayuki; Iida, You*; Aoyagi, Shota*; Sasaki, Yusuke*; Kori, Michinari*; Kishikawa, Keiki*
Macromolecules, 49(16), p.6041 - 6049, 2016/08
Times Cited Count:18 Percentile:58.91(Polymer Science)Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
Hosomi, Kenji; Ma, Y.*; Ajimura, Shuhei*; Aoki, Kanae*; Dairaku, Seishi*; Fu, Y.*; Fujioka, Hiroyuki*; Futatsukawa, Kenta*; Imoto, Wataru*; Kakiguchi, Yutaka*; et al.
Progress of Theoretical and Experimental Physics (Internet), 2015(8), p.081D01_1 - 081D01_8, 2015/08
Times Cited Count:14 Percentile:66.75(Physics, Multidisciplinary)Level structure of the C hypernucleus was precisely determined by means of -ray spectroscopy. We identified four -ray transitions via the C reaction using a germanium detector array, Hyperball2. The spacing of the ground-state doublet was measured to be (stat) (syst)keV from the direct transition. Excitation energies of the and states were measured to be , keV and , keV, respectively. The obtained level energies provide definitive references for the reaction spectroscopy of hypernuclei.
Ogata, Yudai*; Iguchi, Yusuke*; Tokuda, Makoto*; Januszko, K.*; Khandaker, J. I.*; Ono, Masao; Mashimo, Tsutomu*
Journal of Applied Physics, 117(12), p.125902_1 - 125902_6, 2015/03
Times Cited Count:7 Percentile:31.13(Physics, Applied)Kajimoto, Tsuyoshi*; Hashiguchi, Taro*; Shigyo, Nobuhiro*; Satoh, Daiki; Uozumi, Yusuke*; Song, T. Y.*; Lee, C. W.*; Kim, J. W.*; Yang, S. C.*; Koba, Yusuke*; et al.
JAEA-Conf 2014-002, p.127 - 132, 2015/02
Particle transport Monte Carlo codes such as PHITS, FLUKA and so on are used for radiation safety design of high energy accelerators. The validity of code is confirmed by comparison with many experimental data. In this study, we report proton, deuteron, and triton production double differential cross sections (DDXs) from a graphite target by 290 MeV/nucleon Ar ions. The measured spectra are compared with those calculated by PHITS and FLUKA codes.
Shigyo, Nobuhiro*; Uozumi, Yusuke*; Uehara, Haruhiko*; Nishizawa, Tomoya*; Mizuno, Takafumi*; Takamiya, Masanori*; Hashiguchi, Taro*; Satoh, Daiki; Sanami, Toshiya*; Koba, Yusuke*; et al.
Nuclear Data Sheets, 119, p.303 - 306, 2014/05
Times Cited Count:0 Percentile:0.02(Physics, Nuclear)Heavy ion cancer therapy has been increased by reason of its clinical advantages. During the treatment, the secondary particles such as neutron and -ray are produced by nuclear reactions of a heavy ion incidence on a nucleus in a patient body. Estimation of the secondary neutrons yields data is essential for assessment of radiation safety on both of workers and public in treatment facilities. We have measured the neutron yields from carbon ion incidence on carbon, nitrogen and oxygen targets in wide angular range from 15 to 90 with 100- and 290-MeV/u.
Ono, Masao; Okayasu, Satoru; Iguchi, Yusuke*; Esaka, Fumitaka; Bagum, R.*; Haruki, Rie; Mashimo, Tsutomu*
Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan (Internet), 12(ists29), p.Tq_1 - Tq_3, 2014/04
We had realized the composition gradient of elements or isotopes in some binary alloys or single element by solid-state centrifugation. While, it might difficult to realize graded structure of elements in binary ionic crystal by centrifugation as it strongly keeps their stoichiometry. However, isotope fractionation in binary ionic crystal by centrifugation might be expected as the self-diffusion of ions occurs. We have planed the ultracentrifuge experiments on -AgI superionic conductor to investigate the isotope effect in binary ionic crystal under a strong centrifugal acceleration field. -AgI superionic conductor is suitable for the confirmation experiment as it is an intrinsic ionic crystal and Ag ions have high diffusivity. For the first stage, we have experimentally searched the experimental conditions of magnitude of centrifugal acceleration and temperature that ensure the experiment without decomposition. It is confirmed that the combination of experimental conditions of up to 6.110 g, 350C, 24h ensure the experiment without decomposition at least.
Shinohara, Masanori; Motegi, Toshihiro; Saito, Kenji; Haga, Hiroyuki; Sasaki, Shinji; Katsuyama, Kozo; Takada, Kiyoshi*; Higashimura, Keisuke*; Fujii, Junichi*; Ukai, Takayuki*; et al.
JAEA-Technology 2012-032, 29 Pages, 2012/11
An event, in which one of WRMs were disabled to detect the neutron flux in the reactor core, occurred during the period of reactor shut down of HTTR in March, 2010. The actual life time of WRM was unexpectedly shorter than the past developed life time. Investigation of the cause of the outage of WRM toward the recovery of the life time up to the past developed life is one of the issues to develop the technology basis of HTGR. Then, two experimental investigations were carried out to reveal the cause of the malfunction by specifying the damaged part causing the event in the WRM. One is an experiment using a mock-up sample test which strength degradation on assembly accuracy and heat cycle to specify the damaged part in the WRM. The other is a destructive test in FMF to specify the damaged part in the WRM. This report summarized the results of the destructive test and the experimental investigation using the mock-up to reveal the cause of malfunction of WRM.
Motokawa, Ryuhei; Taniguchi, Tatsuo*; Sasaki, Yusuke*; Enomoto, Yuto*; Murakami, Fumiyasu*; Kasuya, Masakatsu*; Kori, Michinari*; Nakahira, Takayuki*
Macromolecules, 45(23), p.9435 - 9444, 2012/11
Times Cited Count:9 Percentile:30.29(Polymer Science)Okayasu, Satoru; Ono, Masao; Nishio, Taichiro*; Iguchi, Yusuke*; Mashimo, Tsutomu*
Defect and Diffusion Forum, 323-325, p.545 - 548, 2012/04
Times Cited Count:0 Percentile:0.01Atomic sedimentation in solid occurs under mega-gravity treatment. As the result, partially melt-growth in -phase of BiPb-alloy occurs. Small difference of densities between fully hcp structure of BiPb and that of partially defected BiPb are enhanced under mega-gravity, and cause the separation of the -phase. Superconducting properties differs between the separated two phases.
Uozumi, Yusuke*; Shigyo, Nobuhiro*; Kajimoto, Tsuyoshi*; Moriguchi, Daisuke*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Satoh, Daiki; Sanami, Toshiya*; Koba, Yusuke*; Takada, Masashi*; et al.
HIMAC-136, p.248 - 249, 2011/11
no abstracts in English
Satoh, Daiki; Moriguchi, Daisuke*; Kajimoto, Tsuyoshi*; Koba, Yusuke*; Nakamura, Yasuhiro*; Shigyo, Nobuhiro*; Ueyama, Masahiko*; Uozumi, Yusuke*; Yoshioka, Masakatsu*; Matsufuji, Naruhiro*; et al.
Journal of the Korean Physical Society, 59(2), p.1741 - 1744, 2011/08
Times Cited Count:3 Percentile:27.61(Physics, Multidisciplinary)The data of neutron production from heavy-ion interactions are of great importance for the dose assessment in heavy-ion therapy. We have already evaluated the data of neutron production for thick targets, in which the incident heavy ions completely stop, by the measurements and the reevaluation of the existing data reported by Kurosawa et al. As a next step of the research, we plan to evaluate the neutron-production cross-section data for thin targets. These data are useful to understand the mechanism of heavy-ion interaction, and improve the reaction model in particle transport codes. The previously reported cross-section data by Iwata et al. were revised by using a new set of neutron-detection efficiency values calculated with SCINFUL-QMD code. While the original data gave the larger values than the predictions of particle transport codes above 200 MeV due to the underestimation of the efficiencies, it was improved by this revision. In addition, we have started the new cross-section measurements at HIMAC. All the data of neutron-production cross sections were compared with the predictions of particle transport codes.
Tanabe, Yusuke*; Nishikawa, Hiroyuki*; Seki, Yoshihiro*; Sato, Takahiro; Ishii, Yasuyuki; Kamiya, Tomihiro; Watanabe, Toru*; Sekiguchi, Atsushi*
Microelectronic Engineering, 88(8), p.2145 - 2148, 2011/08
Times Cited Count:9 Percentile:47.41(Engineering, Electrical & Electronic)Satoh, Daiki; Moriguchi, Daisuke*; Kajimoto, Tsuyoshi*; Uehara, Haruhiko*; Shigyo, Nobuhiro*; Ueyama, Masahiko*; Yoshioka, Masakatsu*; Uozumi, Yusuke*; Sanami, Toshiya*; Koba, Yusuke*; et al.
Nuclear Instruments and Methods in Physics Research A, 644(1), p.59 - 67, 2011/07
Times Cited Count:17 Percentile:77.51(Instruments & Instrumentation)Neutron-production double-differential cross sections on carbon-carbon and oxygen-carbon reactions with incident heavy-ion energy of 290 MeV/nucleon were measured by time-of-flight method using liquid organic scintillators. By use of a detection system specialized for low-energy neutrons, the cross sections were obtained in a wide energy region from several hundred MeV down to 0.6 MeV for the oxygen-ion incidences. The experimental data were compared with the calculation results using the Monte-Carlo simulation code, PHITS. The PHITS results gave an overall agreement with the measured data within a factor of two.