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nodulesHakoyama, Tsuneo*; Oi, Ryo*; Hazuma, Kazuya*; Suga, Eri*; Adachi, Yuka*; Kobayashi, Mayumi*; Akai, Rie*; Sato, Shusei*; Fukai, Eigo*; Tabata, Satoshi*; et al.
Plant Physiology, 160(2), p.897 - 905, 2012/10
Times Cited Count：29 Percentile：67.73(Plant Sciences)Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*; Takano, Masahide; Akabori, Mitsuo; Minato, Kazuo
Journal of Nuclear Materials, 384(1), p.6 - 11, 2009/01
Times Cited Count：9 Percentile：53.3(Materials Science, Multidisciplinary)The indentation hardness, Vickers hardness, fracture toughness, and Young's modulus of polycrystalline uranium monontride (UN) at sub-microscale and macroscale were evaluated by an indentation test, Vickers hardness test, and the ultrasonic pulse echo method. The Young's modulus and Vickers hardness were in good agreement with the literature values. The fracture toughness of UN was about three times that of UO
. In addition, we revealed the indentation size effect on the indentation hardness of UN.
Li, M.*; Nagashio, Kosuke*; Ishikawa, Takehiko*; Mizuno, Akitoshi*; Adachi, Masayoshi*; Watanabe, Masahito*; Yoda, Shinichi*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Acta Materialia, 56(11), p.2514 - 2525, 2008/06
Times Cited Count：23 Percentile：71.73(Materials Science, Multidisciplinary)Co-61.8 at.% Si (CoSe-CoSi) eutectic alloys were solidified on an electromagnetic levitator (EML) and an electrostatic levitator (ESL) at different undercooling levels. The results indicated that there is only a single recalescence event at low undercooling with the CoSi intermetallic compound as primary phase, which is independent of processing facilities, on either an EML or an ESL. The microstructure, however, is strongly dependent on the processing facility. On high undercooling, double recalescence takes place regardless of levitation condition. In situ X-ray diffraction of alloys solidified on the EML demonstrates that the CoSi compound becomes the primary phase upon the first recalescence, and the CoSi intermetallic phase crystallizes during the second recalescence. In addition to phase identification, real-time diffraction patterns can also provide additional evidence of the fragmentation of the primary phase.
Katayama, Masahito*; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Miwa, Shuhei; Osaka, Masahiko; Tanaka, Kenya; Yamanaka, Shinsuke*
Materials Research Society Symposium Proceedings, Vol.1043, p.190 - 195, 2008/00
The molecular dynamics (MD) calculation was performed on minor actinides (MA)-containing mixed oxide (MOX) fuels, (U
Pu
MA
)O (x = 0, 0.016, 0.03, 0.05, 0.1, 0.15), and the lattice parameter, heat capacity and thermal conductivity were evaluated. The calculated thermal conductivity data are comparable in (UPuMA)O at any temperature and any x value, indicating that the thermal conductivity of MA-containing MOX fuels is scarcely influenced by adding MA up to 15 %. The present study shows that the MD calculation can be usefully applied to determine the thermophysical properties of MA-containing MOX fuels.
Osaka, Masahiko; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*
Journal of Nuclear Science and Technology, 44(12), p.1543 - 1549, 2007/12
Times Cited Count：11 Percentile：61.1(Nuclear Science & Technology)no abstracts in English
Takamura, Shuichi*; Kado, Shinichiro*; Fujii, Takashi*; Fujiyama, Hiroshi*; Takabe, Hideaki*; Adachi, Kazuo*; Morimiya, Osamu*; Fujimori, Naoji*; Watanabe, Takayuki*; Hayashi, Yasuaki*; et al.
Kara Zukai, Purazuma Enerugi No Subete, P. 164, 2007/03
no abstracts in English
Kurosaki, Ken*; Adachi, Jun*; Katayama, Masahito*; Osaka, Masahiko; Tanaka, Kenya; Uno, Masayoshi*; Yamanaka, Shinsuke*
Journal of Nuclear Science and Technology, 43(10), p.1224 - 1227, 2006/10
Times Cited Count：11 Percentile：60.27(Nuclear Science & Technology)The molecular dynamics (MD) calculation was performed for americium containing mixed oxide fuels, (UPuAm)O (x = 0, 0.016, 0.03, 0.05, 0.1, 0.15), in the temperature range from 300 to around 2500 K to evaluate the lattice parameter, heat capacity and thermal conductivity. The calculated lattice parameter is found to obey Vegard's law. The MD results reveal that the calculated heat capacity and thermal conductivity are at a similar level in the entire composition range, in other words they are scarcely influenced by adding americium up to 15 %.
Nagashio, Kosuke*; Adachi, Masayoshi*; Higuchi, Kensuke*; Mizuno, Akitoshi*; Watanabe, Masahito*; Kuribayashi, Kazuhiko*; Katayama, Yoshinori
Journal of Applied Physics, 100(3), p.033524_1 - 033524_6, 2006/08
Times Cited Count：14 Percentile：47.16(Physics, Applied)Grain refined microstructure is often obtained spontaneously in the solidification of metals and semiconductors from the undercooled melt without any external forces. Although it has been reported that the grain refinement is mainly caused by the fragmentation of the dendrites, the dynamic process of the fragmentation of dendrites has not been fully understood because the microstructure after the solidification has been analyzed. Here, we present a time-resolved 2- dimensional X-ray diffraction experiment on the solidification of Si from the undercooled melt. The number of diffraction spots observed at low undercoolings (
100K) did not increase at the plateau stage, while the diffraction pattern at medium undercoolings (100K
200K) changed from the spots with the tail to rings with the lapse of time. Both this result and high speed video imaging suggested that the high-order arms of the dendrites mostly detached from the main stems because nucleation could not be expected at the melting point after recalescence. The several spots observed at low undercoolings drastically changed to rings at high undercoolings (
200K), which indicated the complete fragmentation of dendrite main stem as well as high-order arms. This complete fragmentation resulted in the grain refined microstructure.
*; *; *; *; Nakajima, Kunihiko*; Sugihara, Masayoshi; Yamamoto, Shin; Iida, Hiromasa; Fujisawa, Noboru; Mizoguchi, Tadanori*; et al.
JAERI-M 87-137, 72 Pages, 1987/09
no abstracts in English
Katayama, Masahito*; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*; Osaka, Masahiko; Tanaka, Kenya
no journal, ,
Fundamental properties were evaluated by the molecular Dynamics method on (U,Pu,Np,Am)O. Thermal properties of (U,Pu,Np,Am)O having various compositions were calculated.
Katayama, Masahito*; Adachi, Jun*; Kurosaki, Ken*; Osaka, Masahiko; Miwa, Shuhei; Tanaka, Kenya; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*
no journal, ,
no abstracts in English
Katayama, Masahito*; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*; Miwa, Shuhei; Osaka, Masahiko; Tanaka, Kenya
no journal, ,
Thermophysical propoerties of (U,Pu,Np)O were evaluated by the molecular dynamics method for the purpose of understanding the phase relation and thermophysical propoerties of low-decontaminated fuel. Thermophysical properties of (U,Pu,Np)O with various compositions were evaluated.
Osaka, Masahiko; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*
no journal, ,
no abstracts in English
Katayama, Masahito*; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*; Miwa, Shuhei; Tanaka, Kenya; Osaka, Masahiko
no journal, ,
no abstracts in English
Osaka, Masahiko; Adachi, Jun*; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*
no journal, ,
A molecular dynamics study on the defect structure of rare earth-doped thoria was carried out. The partially ionic two-body potential was used with empirically obtained parameters for Th, Gd and O ions in the fluorite structure. Four types of defect structures were assumed and their effects on the lattice parameter were investigated; i.e., oxygen vacancy point defect, Gd-Gd pair, singly charged Gd-vacancy cluster and neutral Gd-vacancy-Gd cluster. Molecular dynamics simulations were carried out with Gd fractions and temperatures ranging from 0 to 45 % and from 298 to 1200 K, respectively. Diffusion coefficients of O ion in the Gd-doped thoria having various Gd fractions were also calculated at 1273 K. Comparison of the calculated results with the experimental ones lead to the conclusion that Gd-oxygen vacancy-Gd type cluster is the most likely defect structure in the Gd-doped thoria.
Kurosaki, Ken*; Katayama, Masahito*; Adachi, Jun*; Uno, Masayoshi*; Miwa, Shuhei; Osaka, Masahiko; Tanaka, Kenya; Yamanaka, Shinsuke*
no journal, ,
The molecular dynamics (MD) calculations were performed on MA-containing mixed oxide (MOX) fuels; in this case MA = Np and Am. The lattice parameter, heat capacity, and thermal conductivity of the MA-containing MOX fuels were evaluated and the effects of the MA content on the properties were studied. The calculated lattice parameter increased with temperature and varied linearly with the MA content. The calculated thermal conductivity data were comparable in MOX at any temperature and any x value, indicating that the thermal conductivity of MA-containing MOX fuels is scarcely influenced by adding MA up to 15 %. This result seems to be reasonable because both the mass and size differences between the ions of uranium and neptunium and/or americium are very small. The present study showed that the MD calculation can be usefully applied to determine the thermal properties of the MA-containing MOX fuels.
Sakurai, Hiroshi*; Tamura, Takuro*; Kurachi, Toshitaka*; Homma, Satoshi*; Oike, Hiromi*; Agui, Akane; Sakurai, Yoshiharu*; Ito, Masayoshi*; Adachi, Hiromichi*; Kawata, Hiroshi*
no journal, ,
no abstracts in English
Hakoyama, Tsuneo*; Oi, Ryo*; Hazuma, Kazuya*; Suga, Eri*; Adachi, Yuka*; Kobayashi, Mayumi*; Akai, Rie*; Sato, Shusei*; Fukai, Eigo*; Tabata, Satoshi*; et al.
no journal, ,
Watanabe, Makoto*; Higashi, Hideo*; Sasaki, Minako*; Adachi, Masayoshi*; Otsuka, Makoto*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi; Yamano, Hidemasa
no journal, ,
This reports results of density measurement of molten iron and nickel that are main components of stainless steel 316 of cladding of control rod as part of thermophysical properties studies of molten control rod material in BWR.
Watanabe, Makoto*; Higashi, Hideo*; Sasaki, Minako*; Adachi, Masayoshi*; Otsuka, Makoto*; Fukuyama, Hiroyuki*; Nishi, Tsuyoshi; Yamano, Hidemasa
no journal, ,
In this study, as a first step, density of the stainless steel 316 (SUS316), pure Fe and Ni were measured. For all samples, the densities are expressed with a linear function of temperature.
