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and GeO liquidsKawaguchi, Munemichi; Uno, Masayoshi*
Journal of Crystal Growth, 585, p.126590_1 - 126590_7, 2022/05
Phase-field mobility, 
, and crystal growth rates in crystallization of 11 oxides or mixed oxides in undercooled silicates, SiO and GeO liquids were calculated with a simple phase-field model (PFM), and material dependence of the was discussed. Ratios between experimental crystal growth rates and the PFM simulation with 
were confirmed to be proportional to a power of 
on the solid/liquid interface process during the crystal growth in a log-log plot. We determined that parameters, 
and 
, of the 
were 
to 
m
J
s and 
to 
, which were unique for the materials. It was confirmed that our PFM simulation with the determined reproduced quantitively the experimental crystal growth rates. The has a proportional relationship with the diffusion coefficient of a cation molar mass average per unit an oxygen molar mass at 
in a log-log graph. The depends on the sum of the cation molar mass per the oxygen molar mass, 
, in a compound. In 
, the decreases with the cation molar mass increasing. The assumed cause is that the B represents the degree of the temperature dependence of the . Since the cation molar mass is proportional to an inertial resistance of the cation transfer, the decreases with inverse of the cation molar mass. In crystallization of the silicates of heavy cation in 
, the saturates at approximately 0.67, which leads to 
.
Baba, Yuji*; Shimoyama, Iwao
Chemical Physics, 550, p.111302_1 - 111302_5, 2021/10
Times Cited Count：2 Percentile：10.62(Chemistry, Physical)The effect of a core-to-valence resonant photoexcitation in an atom on photoemission from the neighboring atoms has been experimentally investigated. For SiO
fine powder mixed with boron nitride matrix, it was found that the intensity of the O 
photoelectrons was reduced around the Si 
resonant photoexcitation. On the other hand, the intensity of the B or N photoelectrons from the matrix material did not change regardless of the photon energy. Similar phenomenon was also observed for Si
N
powder mixed with cellulose as a matrix material. The results demonstrated that photoemission from the nearest-neighbor atoms that are directly bound to silicon is perturbated by the core-to-valence resonant photoexcitation in silicon. Using the phenomenon, it is expected that species of the nearest neighbor atom can be identified by a resonant core-level excitation in a target atom.
Hidaka, Akihide
Proceedings of 2021 International Congress on Advances in Nuclear Power Plants (ICAPP 2021) (USB Flash Drive), 10 Pages, 2021/10
Author recently proposed that the Type A glassy Cesium-bearing microparticles that were released during the Fukushima accident may have been formed by melting and atomization of glass fibers of the High Efficiency Particulate Air (HEPA) filter in the Stand-by Gas Treatment System (SGTS) line in Unit 3 during the hydrogen explosion. In the present study, the components of the Type A and glass fibers of HEPA filter were examined using EPMA. The results showed that the components of the Type A were almost the same as that of the glass fibers except for Cs, Fe, Sn, which are considered to have been contained in the in-vessel-derived particles. When the glass fiber was irradiated with the electron beam of the Electron Probe Micro Analyzer (EPMA) under vacuum condition, spherical particles of a few micro m size were formed that looked very similar to the Type A. These strongly suggest that the HEPA filter is Si source of the Type A.
Myagmarjav, O.; Shibata, Ai*; Tanaka, Nobuyuki; Noguchi, Hiroki; Kubo, Shinji; Nomura, Mikihiro*; Takegami, Hiroaki
International Journal of Hydrogen Energy, 46(56), p.28435 - 28449, 2021/08
Times Cited Count：4 Percentile：9.91(Chemistry, Physical)
H monitoring in radioactive gaseous wasteFurutani, Misa; Kometani, Tatsunari; Nakagawa, Masahiro; Ueno, Yumi; Sato, Junya; Iwai, Yasunori*
Hoken Butsuri (Internet), 55(2), p.97 - 101, 2020/06
Herein, an oxidation catalyst was introduced after heating it to 600
C to oxidize tritium gas (HT) existing in exhaust into tritiated water vapor (HTO). This study aims to establish a safer H monitoring system by lowering the heating temperature required for the catalyst. In these experiments, which were conducted in the Nuclear Science Research Institute, Japan Atomic Energy Agency, cupric oxide, hydrophobic palladium/silicon dioxide (Pd/SiO), and platinum/aluminum oxide (Pt/AlO) catalysts were ventilated using standard hydrogen gas. After comparing the oxidation efficiency of each catalyst at different temperatures, we found that the hydrophobic Pd/SiO and Pt/AlO catalysts could oxidize HT into HTO at 25C.
C monitoring in gaseous radioactive wasteUeno, Yumi; Nakagawa, Masahiro; Sato, Junya; Iwai, Yasunori
Hoken Butsuri, 51(1), p.7 - 11, 2016/03
In the Nuclear Science Research Institute, Japan Atomic Energy Agency (JAEA), in order to oxidize C, which exists in various chemical forms in exhaust, into CO, a copper oxide (CuO) catalyst is introduced after heating to 600C. Our goal was to establish a safer C monitoring system by lowering the heating temperature required for the catalyst; therefore, we developed a new hydrophobic palladium/silicon dioxide (Pd/SiO) catalyst that makes the carrier's surface hydrophobic. In these experiments, catalysts CuO, platinum/aluminum oxide (Pt/AlO), palladium/zirconium dioxide (Pd/ZrO), hydrophobic Pd/SiO, and hydrophilic Pd/SiO were ventilated with standard methane gas, and we compared the oxidation efficiency of each catalyst at different temperatures. As a result, we determined that the hydrophobic Pd/SiO catalyst had the best oxidation efficiency. By substituting the currently used CuO catalyst with the hydrophobic Pd/SiO catalyst, we will be able to lower the working temperature from 600C to 300C and improve the safety of the monitoring process.
film formed by a hyperthermal O-atom beam at room temperatureTagawa, Masahito*; Sogo, Chie*; Yokota, Kumiko*; Hachiue, Shunsuke; Yoshigoe, Akitaka; Teraoka, Yuden
Japanese Journal of Applied Physics, 44(12), p.8300 - 8304, 2005/12
Times Cited Count：5 Percentile：21.43(Physics, Applied)Si oxide layers formed on Si(001) substrates by irradiation of hyperthermal oxygen atomic beams at room temperature were analysed at the JAERI soft X-ray beamline by photoemission spectroscopy. It was found that sub-oxide components were scarcely observed in the Si oxide layers formed by the atomic oxygen beam.
Maekawa, Masaki; Kawasuso, Atsuo; Yoshikawa, Masahito; Ichimiya, Ayahiko
Materials Science Forum, 445-446, p.144 - 146, 2004/05
no abstracts in English
Ishino, Masahiko; Yoda, Osamu; Takenaka, Hisataka*; Sano, Kazuo*; Koike, Masato
Surface & Coatings Technology, 169-170(1-3), p.628 - 631, 2003/06
no abstracts in English
Ishino, Masahiko; Yoda, Osamu
Journal of Applied Physics, 92(9), p.4952 - 4958, 2002/11
Times Cited Count：6 Percentile：27.99(Physics, Applied)no abstracts in English
Iida, Takeshi*; Tomioka, Yuichi*; Yoshimoto, Kimihiro*; Midorikawa, Masahiko*; Tsukada, Hiroyuki*; Orihara, Misao*; Hijikata, Yasuto*; Yaguchi, Hiroyuki*; Yoshikawa, Masahito; Ito, Hisayoshi; et al.
Japanese Journal of Applied Physics, Part 1, 41(2A), p.800 - 804, 2002/02
Times Cited Count：16 Percentile：53.58(Physics, Applied)no abstracts in English
/4H-SiC(0001) interfaceYamashita, Kenya*; Kitabatake, Makoto*; Kusumoto, Osamu*; Takahashi, Kunimasa*; Uchida, Masao*; Miyanaga, Ryoko*; Ito, Hisayoshi; Yoshikawa, Masahito
Materials Science Forum, 389-393, p.1037 - 1040, 2002/00
Times Cited Count：3 Percentile：15.87(Materials Science, Multidisciplinary)no abstracts in English
-implanted SiO/Si studied by positron annihilation and cathodoluminescenceHirata, Koichi*; Arai, Hideyuki*; Kawasuso, Atsuo; Sekiguchi, T.*; Kobayashi, Yoshinori*; Okada, Sohei
Journal of Applied Physics, 90(1), p.237 - 242, 2001/07
Times Cited Count：4 Percentile：21.55(Physics, Applied)no abstracts in English
-
transition of cristobalite, SiO; A Molecular-dynamics studyKimizuka, Hajime*; Kaburaki, Hideo; Kogure, Yoshiaki*
Physical Review Letters, 84(24), p.5548 - 5551, 2000/06
Times Cited Count：145 Percentile：94.62(Physics, Multidisciplinary)no abstracts in English
/Si studied by slow positron beamKawasuso, Atsuo; Arai, H.*; Hirata, K.*; Sekiguchi, T.*; Kobayashi, Yoshinori*; Okada, Sohei
Radiation Physics and Chemistry, 58(5-6), p.615 - 619, 2000/06
Times Cited Count：3 Percentile：26.10(Chemistry, Physical)no abstracts in English
/Si layer by high-energy XPSYamamoto, Hiroyuki; Baba, Yuji
Journal of Surface Analysis, 7(1), p.122 - 127, 2000/03
no abstracts in English
/Si layerYamamoto, Hiroyuki; Baba, Yuji
Photon Factory Activity Report 1998, P. 136, 1999/11
no abstracts in English
Shikama, Tatsuo*; Ishihara, Masahiro; Hayashi, Kimio; Kakuta, Tsunemi; Shamoto, Naoki*; Ishino, Shiori*
Proceedings of 1st Information Exchange Meeting on Basic Studies on High-Temperature Engineering, p.379 - 386, 1999/09
no abstracts in English
by MeV Au ion implantation and subsequent thermal annealingDai, Z.*; Yamamoto, Shunya; Narumi, Kazumasa; Miyashita, Atsumi; Naramoto, Hiroshi
Nuclear Instruments and Methods in Physics Research B, 149(1-2), p.108 - 112, 1999/00
Times Cited Count：18 Percentile：76.71(Instruments & Instrumentation)no abstracts in English
Dai, Z.*; Yamamoto, Shunya; Naramoto, Hiroshi; Narumi, Kazumasa; Miyashita, Atsumi
1998 International Conference on Ion Implantation Technology Proceedings, Vol.2, p.1159 - 1162, 1998/06
no abstracts in English
