JOPSS - Search Results

Ultracentrifuge experiments were performed on the In-Pb system to study the sedimentation of atoms and phase equilibrium. After the experiments, the graded structures were obtained. Pb-rich phase (f.c.c) and In-rich phase (tetragonal) appeared at the strong- and weak-gravitational field sides of the sample, respectively, from starting state of -phase. And, the continuous changes in lattice parameters were observed in each phase. These observation results showed that the graded structure was continuous in atomic scale, and was formed by the sedimentation of atoms. Composition profiles of the centrifuged samples for 31.3 h, 60 h and 150 h showed that the composition change reached the steady state within 60 hours. The diffusion coefficient for sedimentation was estimated to be about 8 times larger than that for usual diffusion by the simulation. The result indicated that the diffusion mechanism of the sedimentation was different from the conventional ones.

Journal Articles

Determination of low-pressure crystalline-liquid phase boundary of SnI $_{4}$

Fuchizaki, Kazuhiro*; Fujii, Yasuhiko*; Oishi, Yasuo*; Omura, Ayako*; Hamaya, Nozomu*; Katayama, Yoshinori; Okada, Taku

Journal of Chemical Physics, 120(23), p.11196 - 11199, 2004/06

https://doi.org/10.1063/1.1751397

Times Cited Count：22 Percentile：58.21(Chemistry, Physical)

The location of the liquidus in the low-pressure crystalline phase of SnI $_{4}$ was determined utilizing X-ray diffraction measurements under pressures up to approximately GPa. The liquidus is not well fitted to a monotonically increasing curve such as Simon's equation, but breaks near GPa and then becomes almost flat. The results are compared to those from molecular dynamics simulations. Ways to improve the model potential adopted in the simulations are discussed.

Journal Articles

Pressure-induced sharp coordination change in liquid germanate

Otaka, Osamu*; Arima, Hiroshi*; Fukui, Hiroyuki*; Utsumi, Wataru; Katayama, Yoshinori; Yoshiasa, Akira*

Physical Review Letters, 92(15), p.155506_1 - 155506_4, 2004/04

https://doi.org/10.1103/PhysRevLett.92.155506

Times Cited Count：51 Percentile：84.23(Physics, Multidisciplinary)

Local structures around germanium in liquid germanate have been investigated by means of in situ X-ray absorption measurements up to 9 GPa at 1273 K. Liquid germanate consisting of tetrahedrally coordinated germanium contracts with increasing pressure without significant changes in the local structure up to 2.5 GPa and then shows an abrupt fourfold-to-sixfold coordination change around 3 GPa. The coordination change is completed below 4 GPa where upon a high-density liquid consisting of octahedrally coordinated germanium becomes stable. The GeO $_{6}$ octahedron in the high-density liquid is more compressible than that in solids.

JAEA Reports

Present status and future subjects of the analytical studies related with application of charged particles and RI to materials science and biotechnology

Working Group in the Advisory Committee of the Analytical Studies for Application of Charged Particl

JAERI-Review 2003-008, 42 Pages, 2003/03

JAERI-Review-2003-008.pdf:3.12MB

The position in the research field of radiation application of "Theoretical Analysis Group for Radiation Application" which will be set up within fiscal 2003, and the relation between the research that this analytical group will advance in future and the analytical research made so far at JAERI Takasaki are summarized. First, the theoretical analysis group for radiation application extracts only the core element from the analysis of reactive process of charged particles in the materials and from the irradiation effect, and then constructs the simplified model. Second, the validity of the constructed model is verified by advancing the theoretical analysis based on the model, and the calculated result is fed back to the experiment, and then the verification is carried out. Finally, the general-purpose theorization will be conducted by generalizing and universalizing the obtained model concerning the specific system. The obtained outcomes will be applied to other systems, and, will consequently, contribute to the promotion of new technological development.

Journal Articles