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The structure of Cu67Zr33 amorphous alloy was investigated in terms of packing density and free volume by using neutron, x-ray diffraction and reverse Monte Carlo (RMC) modelling. The RMC model was analysed by a method of decomposing the three-dimensional atomic configuration into fundamental polyhedral units (termed as ‘holes’ referencing the Bernal’s works) of which faces are all triangles consisting of chemical bonds. Not only tetrahedral and octahedral holes but also other larger holes were identified. Moreover, the atomic packing fractions and free volumes in the respective polyhedral holes were evaluated with reference to those for the corresponding crystal structures. The results show that the distribution of free volumes for the larger holes can be described by the exponential function assuming that there are no energetic interactions between each other. On the other hand, the local structural fluctuations due to densely and loosely packed tetrahedral holes were observed, leading to the negative free volume spaces.

Thermoelectric material SnSe has aroused world-wide interests in the past years, and its inherent strong lattice anharmonicity is regarded as a crucial factor for its outstanding thermoelectric performance. However, the understanding of lattice anharmonicity in SnSe system remains inadequate, especially regarding how phonon dynamics are affected by this behavior. In this work, we present a comprehensive study of lattice dynamics on Na0.003Sn0.997Se0.9S0.1 by means of neutron total scattering, inelastic neutron scattering, Raman spectroscopy as well as frozen-phonon calculations. Lattice anharmonicity is evidenced by pair distribution function, inelastic neutron scattering and Raman measurements. By separating the effects of thermal expansion and multi-phonon scattering, we found that the latter is very significant in high-energy optical phonon modes. The strong temperature-dependence of these phonon modes indicate the anharmonicity in this system. Moreover, our data reveals that the linewidths of high-energy optical phonons become broadened with mild doping of sulfur. Our studies suggest that the thermoelectric performance of SnSe could be further enhanced by reducing the contributions of high-energy optical phonon modes to the lattice thermal conductivity via phonon engineering.

Reverse Monte Carlo modeling was carried out for Li7P3S11 metastable crystal and (Li2S)70(P2S5)30 glass based on time-of-flight neutron and synchrotron X-ray diffraction data. Polyhedral analysis of three-dimensional structures for Li7P3S11 metastable crystal and (Li2S)70(P2S5)30 glass were gave us not only structural characteristics but also structural origins related to their high ionic conductivity.

Synchrotron X-ray and neutron diffraction measurements were carried out for (7Li2S)x(P2S5)100?x glasses and a 7Li7P3Sn11 metastable crystal. The Reverse Monte Carlo (RMC) modeling provided us the three-dimensional structures of (7Li2S)x(P2S5)100?x and 7Li7P3S11, particularly the distribution of Li+ cations.

Hydrogen and deuterium pressure-composition (P-C) isotherm measurements were carried out for Ti0.31Cr0.49V0.20 bcc alloy. As a result, the residual hydrogen-to-metal ratio (H/M)res was almost the same as the residual deuterium-to-metal one (D/M)res; the (H/M)res and (D/M)res were approximately 0.5. Furthermore, the neutron scattering experiments were conducted with Ti0.31Cr0.49V0.20 alloys including the residual hydrogen and/or deuterium. It was found that H atoms absorbed in the first absorption cycle up to H/M = 0.5 are hardly bound in the desorption cycle as the residual hydrogen, whereas D atoms are mainly bound in Ti0.31Cr0.49V0.20 bcc alloy as the residual deuterium when D2 gas is partially used in the H absorption reaction.

Electrical conductivity, X-ray absorption near edge structure (XANES), and synchrotron X-ray diffraction (SXRD) measurements were carried out for (Li2S)x(P2S5)100-x glasses synthesized by a mechanical alloying (MA) technique. It was found that the electrical conductivity of (Li2S)x(P2S5)100-x suddenly increases by more than an order of magnitude in the x region between 25 and 30. Simultaneously, the XANES spectrum also changed drastically. In addition, the Reverse Monte Carlo (RMC) simulation gave us the detailed amorphous structures of (Li2S)20(P2S5)80 and (Li2S)40(P2S5)60, particularly a distribution of Li+ cations in a [PS4] tetrahedron-network was revealed for each sample.

X-ray powder diffraction (XRD) and small-angle neutron scattering (SANS) experiments were carried out for the hydrogenated and duterated Mg2Ni, respectively. According to the results of XRD experiments, both of them coexisted with unhydrogenated (or undeuterated) Mg2Ni in the hydrogen absorbing cycle. Furthermore, in the SANS experiments, a slope of SANS curve, I(Q), was roughly evaluated by using the following power law: I(Q) ∝ Q−m, where Q is the magnitude of the scattering vector, and m can be equated with a fractal dimensionality, DS (= 6 − m). In conclusion, the hydrogenated and duterated Mg2Ni showed DS~ 3 and ~ 2, respectively. The significant difference between DS's can be understood by considering the scattering length densities, ρ, of Mg2Ni, Mg2NiH4, and Mg2NiD4.

DAQ-Middleware is a software framework of network-distributed DAQ system based on Robot Technology Middleware, which is an international standard of Object Management Group (OMG) in Robotics and its implementation was developed by AIST. DAQ-Component is a software unit of DAQ-Middleware. Basic components have been already developed. For examples, Gatherer is a readout component, Logger is a data logging component, Monitor is an analysis component and Dispatcher, which is connected to Gatherer as input of data path and to Logger/Monitor as output of data path. DAQ operator is a special component, which controls those components by using the control/status path. The control/status path and data path as well as XML-based system configuration and XML/HTTP-based system interface are well defined in DAQ-Middleware framework. DAQ-Middleware was adopted by experiments at J-PARC while the commissioning at the first beam had been successfully carried out. The functionality of DAQ-Middleware and the status of DAQ-Middleware at J-PARC are presented.

To reveal hydrogen-metal interaction in metal hydride systems with high hydrogen density, we have constructed the high-pressure device for neutron diffraction at total scattering spectrometer NOVA in J-PARC. The device consists of the Paris-Edinburgh press, the alignment stages, the automatically regulated oil pump system and the temperature control system. By using this device, diffraction data are expected to be taken at pressures above 20 GPa over wide Q-range of 1-40A−1 with the resolution of ΔQ/Q~0.6 %, which enables us to determine hydrogen positions in high hydrogen-density materials in the real-space resolution of 0.16A.

X-ray diffraction measurement was performed on an Mg50Ni50 amorphous alloy prepared by mechanical alloying under an Ar atmosphere. Reverse Monte Carlo (RMC) simulation based on the X-ray diffraction data was used to construct a three-dimensional atomic arrangement of the amorphous alloy. In addition, the local environments around the Mg and Ni atoms were investigated by using Voronoi polyhedral analysis on the RMC configuration. The results show that isosahedral structures are predominant around the Mg and Ni atoms in Mg50Ni50, although prismatic local structures are present around some of the Ni atoms.

Collective dynamics of metallic glass CuZr2 has been studied in the first pseudo Brillouin zone using high-resolution inelastic X-ray scattering. Acoustic-like longitudinal propagating excitations were observed and the dispersion relation was determined. In addition of longitudinal mode, transverse mode with half excitation energy contributes to medium energy-transfer region.