Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ebihara, Kenichi; Sekine, Daiki*; Sakiyama, Yuji*; Takahashi, Jun*; Takai, Kenichi*; Omura, Tomohiko*
International Journal of Hydrogen Energy, 48(79), p.30949 - 30962, 2023/09
Times Cited Count：0 Percentile：0.01(Chemistry, Physical)To understand hydrogen embrittlement (HE), which is one of the stress corrosion cracking of steel materials, it is necessary to know the H distribution in steel, which can be effectively interpreted by numerical simulation of thermal desorption spectra. In weld metals and TRIP steels, residual austenite significantly influences the spectra, but a clear H distribution is not well known. In this study, an originally coded two-dimensional model was used to numerically simulate the previously reported spectra of high-carbon ferritic-austenitic duplex stainless steels, and it was found that H is mainly trapped at the carbide surface when the amount of H in the steel is low and at the duplex interface when the amount of H is high. It was also found that the thickness dependence of the H desorption peak for the interface trap site is caused by a different reason than the conventional one.
Ebihara, Kenichi; Sugiyama, Yuri*; Matsumoto, Ryosuke*; Takai, Kenichi*; Suzudo, Tomoaki
Metallurgical and Materials Transactions A, 52(1), p.257 - 269, 2021/01
Times Cited Count：9 Percentile：51.51(Materials Science, Multidisciplinary)We simulated the thermal desorption spectra of a small-size iron specimen to which was applied during charging with hydrogen atoms using a model incorporating the behavior of vacancies and vacancy clusters. The model considered up to vacancy clusters 
, which is composed of nine vacancies and employed the parameters based on atomistic calculations, including the H trapping energy of vacancies and vacancy clusters that we estimated using the molecular static calculation. As a result, we revealed that the model could, on the whole, reproduced the experimental spectra except two characteristic differences, and also the dependence of the spectra on the aging temperature. By examining the cause of the differences, the possibilities that the diffusion of clusters of 
and 
is slower than the model and that vacancy clusters are generated by applying strain and H charging concurrently were indicated.
Miyazaki, Yasunori; Adachi, Junichi*; Masuda, Ryotaro*; Gejo, Tatsuo*; Hoshino, Masamitsu*
Photon Factory Activity Report 2021 (Internet), 2 Pages, 2021/00
no abstracts in English
Ebihara, Kenichi; Saito, Kei*; Takai, Kenichi*
"Suiso Zeika No Kihon Yoin To Tokusei Hyoka" Kenkyukai Hokokusho, p.57 - 61, 2018/09
no abstracts in English
Ebihara, Kenichi; Saito, Kei*; Takai, Kenichi*
Proceedings of 2016 International Hydrogen Conference (IHC 2016); Materials Performance in Hydrogen Environments, p.470 - 477, 2017/00
For understanding hydrogen (H) embrittlement of steels, it is necessary to infer the state that defects trap H in the steels. Thermal desorption spectra of H obtained by the thermal desorption spectrometry (TDS) are used for inferring such a state. Because the thermal desorption spectra include the influence of experimental conditions and hydrogen diffusion as well as information of the defects trapping H, it is necessary to interpret the spectra using the numerical simulation. In the presentation, we determined the detrapping and the trapping rate constants which are necessary for the simulation from the experimental spectra obtained for plate specimens which is so small that H diffusion is ignorable. Then we confirmed that the model using the obtained rate constants can simulate the spectra of larger cylindrical specimens, so that it was found that the rate constant for small specimens can be used for the simulation of the spectra for specimens of different shape or size.
Ebihara, Kenichi; Saito, Kei*; Takai, Kenichi*
"Suiso Zeika No Kihon Yoin To Tokusei Hyoka Kenkyukai Chukan Hokokukai" Shimposium Yokoshu (USB Flash Drive), p.30 - 35, 2016/09
no abstracts in English
Nakamura, Kazuya*; Yamamoto, Yusuke*; Suzuki, K.*; Takao, Tomoaki*; Murakami, Haruyuki; Natsume, Kyohei; Yoshida, Kiyoshi
IEEE Transactions on Applied Superconductivity, 25(3), p.4200704_1 - 4200704_4, 2015/06
Times Cited Count：0 Percentile：0(Engineering, Electrical & Electronic)Takao, Tomoaki*; Kawahara, Yuzuru*; Nakamura, Kazuya*; Yamamoto, Yusuke*; Yagai, Tsuyoshi*; Murakami, Haruyuki; Yoshida, Kiyoshi; Natsume, Kyohei*; Hamaguchi, Shinji*; Obana, Tetsuhiro*; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4800804_1 - 4800804_4, 2014/06
Times Cited Count：3 Percentile：21.9(Engineering, Electrical & Electronic)no abstracts in English
Harries, J.; Gejo, Tatsuo*; Homma, Kenji*; Kuniwake, Miki*; Sullivan, J. P.*; Lebech, M.*; Azuma, Yoshiro*
Journal of Physics B; Atomic, Molecular and Optical Physics, 44(9), p.095101_1 - 095101_7, 2011/05
Times Cited Count：9 Percentile：44.05(Optics)
transitions in N
OTravnikova, O.*; C
olin, D.*; Bao, Z.*; B
rve, K. J.*; Tanaka, Takahiro*; Hoshino, Masamitsu*; Kato, Hideki*; Tanaka, Hiroshi*; Harries, J.; Tamenori, Yusuke*; et al.
Journal of Electron Spectroscopy and Related Phenomena, 181(2-3), p.129 - 134, 2010/08
Times Cited Count：1 Percentile：7.38(Spectroscopy)In NO a detailed study of the vibrational distribution of the state reached after decay of core-to- excitation of N terminal, N central and O 1s core levels is reported. We observe a change in the relative intensity of bending versus stretching modes while scanning the photon energy across all three resonances. While this effect is known to be due to the Renner-Teller splitting in the core-excited states, we could derive that the antisymmetric stretching is excited mainly in the decay of the N terminal 1s-to- excitation. An explanation for such selectivity is provided in terms of interplay of vibrational structure on potential energy surfaces of different electronic states involved in the process.
I and thermally dissociated CFI near the C 1s, I 3d and F 1s ionisation thresholdsTanaka, Takahiro*; Hoshino, Masamitsu*; Kato, Hideki*; Harries, J.; Tamenori, Yusuke*; Ueda, Kiyoshi*; Tanaka, Hiroshi*
Journal of Electron Spectroscopy and Related Phenomena, 164(1-3), p.24 - 27, 2008/07
Times Cited Count：4 Percentile：24.52(Spectroscopy)We report soft X-ray total ion yield and angular-resolved ion yield spectra of CFI in the C 1s, I 3d and F 1s ionisation regions, and tentatively assign the observed electronic states. Anisotropy in ion yield is observed only for the C 1s
transition, indicating that the dipole moment for this transition is parallel to the C
. The effusive source of CFI is heated to 800 K to produce a mixture of CF and I, and the resulting spectra are compared to those recorded at room temperature to reveal the first information on the inner-shell excitation of CF.
Goto, Kenji*; Osakabe, Toyotaka; Kakurai, Kazuhisa; Uwatoko, Yoshiya*; Osawa, Akira*; Kawakami, Jun*; Tanaka, Hidekazu*
Journal of the Physical Society of Japan, 76(5), p.053704_1 - 053704_4, 2007/05
Times Cited Count：12 Percentile：57.87(Physics, Multidisciplinary)The neutron scattering investigation on magnetic excitations in KCuCl under applied pressure was performed. The softening of the excitation mode at a hydrostatic pressure of 4.7kbar was clearly observed. From the analysis of the dispersion relations, it was found that the intradimer interaction decreases under hydrostatic pressure, while most of the interdimer interactions increase.
Osawa, Akira*; Kakurai, Kazuhisa; Nishiwaki, Yoichi*; Kato, Tetsuya*
Journal of the Physical Society of Japan, 75(7), p.074719_1 - 074719_4, 2006/07
Times Cited Count：6 Percentile：41.83(Physics, Multidisciplinary)Polarized neutron inelastic scattering experiments have been carried out in the quasi-1D Ising-like antiferromagnet TlCoCl. We observed the longitudinal magnetic fluctuation S
(Q,
) for the spin-wave excitation continuum for the first time, together with the transverse magnetic fluctuation S
(Q,). We compared both obtained intensities of S(Q,) and S(Q,) with the predictions of the perturbation theory from the pure Ising limit by Ishimura and Shiba.
Goto, Kenji; Fujisawa, Masashi*; Tanaka, Hidekazu*; Uwatoko, Yoshiya*; Osawa, Akira*; Osakabe, Toyotaka; Kakurai, Kazuhisa
Journal of the Physical Society of Japan, 75(6), p.064703_1 - 064703_7, 2006/06
Times Cited Count：29 Percentile：76.34(Physics, Multidisciplinary)Magnetization and neutron elastic scattering experiments under hydrostatic pressure were performed on KCuCl, which is a three-dimensionally coupled spin dimer system with a gapped ground state. It was found that the intradimer interaction decreases with increasing hydrostatic pressure, while the sum of the interdimer interactions increases. This leads to the shrinkage of the spin gap. A quantum phase transition from a gapped state to an antiferromagnetic state occurs at Pc
8.2 kbar. For P
Pc, magnetic reflections were observed at reciprocal lattice points equivalent to those for the lowest magnetic excitation at zero temperature. This confirms that the spin gap decreases and closes under applied pressure.
H
isomersMakochekanwa, C.*; Kato, Hidetoshi*; Hoshino, Masamitsu*; Tanaka, Hiroshi*; Kubo, Hirotaka; Bettega, M. H. F.*; Lopes, A. R.*; Lima, M. A. P.*; Ferreira, L. G.*
Journal of Chemical Physics, 124(2), p.024323_1 - 024323_9, 2006/00
Times Cited Count：16 Percentile：48.34(Chemistry, Physical)no abstracts in English
and KCuCl under applied pressureGoto, Kenji*; Fujisawa, Masashi*; Osawa, Akira*; Kakurai, Kazuhisa; Osakabe, Toyotaka; Uwatoko, Yoshiya*; Tanaka, Hidekazu*
no journal, ,
no abstracts in English
Kakurai, Kazuhisa; Osawa, Akira*; Nishiwaki, Yoichi*; Kato, Tetsuya*
no journal, ,
We report the results of polarized neutron inelastic scattering experiments on the quasi-one dimensional Ising-like antiferromagnet TlCoCl. The longitudinal spin fluctuation in the spin-wave excitation continuum has been clearly identified. The observed longitudinal fluctuation together with the transverse fluctuation are compared with the predictions of the perturbation theory from the pure Ising limit by Ishimura and Shiba.
Nishiwaki, Yoichi*; Osawa, Akira*; Kakurai, Kazuhisa; Nakamura, Tota*; Todoroki, Norikazu*; Kuroe, Haruhiko*; Kato, Tetsuya*
no journal, ,
no abstracts in English
Nagata, Hiroshi*; Honda, Teruyuki*; Iwatsuki, Teruki
no journal, ,
Trace elements analysis have been carryed out to estimate the migration property of fault zone at Horonobe area, Hokkaido. The results show that the light Ln elements are highly sorped on the clay minerals in fault zone.
fluorescence following O(1s) excitation/ionisation in gas-phase water moleculesHarries, J.; Gejo, Tatsuo*; Sullivan, J. P.*; Azuma, Yoshiro*
no journal, ,
In this research we have obtained new information on the photo-dissociation dynamics of the water molecule following O (1s) inner-shell excitation/ionisation. When the O 1s electron is excited neutral excited H atoms can be produced. By investigating which states these H atoms are information can be obtained on the dissociation routes. When the inner-shell O 1s electron is excited/ionises, an unstable HO
ion core is formed. This is unstable, and Auger decay occurs. The resulting HO
ion core dissociates, and one of the fragments can capture the initially excited electron. When this fragment is H, a neutral H atom is formed. In this research we use the pulsed nature of synchrotron radiation to study the lifetimes of the fluorescing excited states produced.
