An X-ray and neutron scattering study of aqueous MgCl solution in the gigapascal pressure range

Yamaguchi, Toshio*; Fukuyama, Nami*; Yoshida, Koji*; Katayama, Yoshinori*; Machida, Shinichi*; Hattori, Takanori

Liquids, 3(3), p.288 - 302, 2023/09

https://doi.org/10.3390/liquids3030019

We report the structure of an aqueous 2 mol/kg MgCl solution at pressures from 0.1 MPa to 4 GPa and temperatures from 300 to 500 K revealed by X-ray and neutron scattering measurements. The scattering data are analyzed by empirical potential structure refinement (EPSR) modeling to derive the pair distribution functions, coordination number distributions, angle distributions, and spatial density functions as a function of pressure and temperature. Mg forms rigid solvation shells extended to the third shell; the first solvation shell of six-fold octahedral coordination with about six water molecules at 0 GPa transforms into about five water molecules and one Cl due to the formation of the contact ion pairs in the GPa pressure range. The Cl solvation shows a substantial pressure dependence; the coordination number of a water oxygen atom around Cl increases from 8 at 0.1 MPa/300 K to 10 at 4 GPa/500 K. The solvent water transforms the tetrahedral network structure at 0.1 MPa/300 K to a densely packed structure in the GPa pressure range; the number of water oxygen atoms around a central water molecule gradually increases from 4.6 at 0.1 MPa/298 K to 8.4 at 4 GPa/500 K.

Synthesis and formation process of AlCuH; A New class of interstitial aluminum-based alloy hydride

Saito, Hiroyuki; Takagi, Shigeyuki*; Endo, Naruki; Machida, Akihiko; Aoki, Katsutoshi; Orimo, Shinichi*; Katayama, Yoshinori

APL Materials (Internet), 1(3), p.032113_1 - 032113_7, 2013/09

https://doi.org/10.1063/1.4821632

Real-time X-ray diffraction of metastable phases during solidification from the undercooled LuFeO melt by two-dimensional detector at 1 kHz

Kumar, M. V.*; Kuribayashi, Kazuhiko*; Nagashio, Kosuke*; Ishikawa, Takehiko*; Okada, Jumpei*; Yu, J.*; Yoda, Shinichi*; Katayama, Yoshinori

Applied Physics Letters, 100(19), p.191905_1 - 191905_4, 2012/05

https://doi.org/10.1063/1.4712124

identification of metastable phases formed from the undercooled LuFeO melt under controlled oxygen partial pressure o was studied by X-ray diffraction measurements at a synchrotron radiation source. Real-time observation of the formation and growth of individual phases during the single recalescence of LuFeO and LuFeO phases at o of 110 Pa has been revealed by a high speed imaging system at 1 kHz. The obtained diffraction pattern of the metastable phase in the LuFeO system was consistent with that of the metastable and stable phases reported in the Lu-Fe-O system.

Hydrogen storage using aluminum hydride

Ikeda, Kazuki*; Orimo, Shinichi*; Saito, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori; Aoki, Katsutoshi

Suiso Seizo, Kyuzo, Chozo Zairyo To Anzenka, p.317 - 327, 2010/08

AlH is a metal hydride with a large gravimetric and volumetric hydrogen content (10.1 wt.% and 149kgH/m, respectively), and therefore it is promising as a hydrogen storage material. The high capacity and low desorption temperature (80150C) have attracted much attention. In situ X-ray diffraction measurements for the Al-H binary system at high pressures and temperatures were performed to investigate the hydrogenation of aluminum metal immersed in hydrogen fluid as well as the phase stability of the aluminum hydride formed.

Heavy fermion state in YbIrZn

Yoshiuchi, Shingo*; Toda, Masatoshi*; Matsushita, Masaki*; Yasui, Shinichi*; Hirose, Yusuke*; Oya, Masahiro*; Katayama, Keisuke*; Honda, Fuminori*; Sugiyama, Kiyohiro*; Hagiwara, Masayuki*; et al.

Journal of the Physical Society of Japan, 78(12), p.123711_1 - 123711_4, 2009/12

https://doi.org/10.1143/JPSJ.78.123711

Microstructure formation and in situ phase identification from undercooled Co-61.8 at.% Si melts solidified on an electromagnetic levitator and an electrostatic levitator

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

https://doi.org/10.1016/j.actamat.2008.01.041

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.

A New measurement of the astrophysical Li(, n)B reaction

Ishiyama, Hironobu*; Hashimoto, Takashi; Ishikawa, Tomoko*; Watanabe, Yutaka*; Das, S. K.*; Miyatake, Hiroari; Mizoi, Yutaka*; Fukuda, Tomokazu*; Tanaka, Masahiko*; Fuchi, Yoshihide*; et al.

Physics Letters B, 640(3), p.82 - 85, 2006/09

https://doi.org/10.1016/j.physletb.2006.07.036

The excitation function of the Li(,n)B reaction was measured while identifying the final state event by event in the region of E = 0.7 - 2.6 MeV using a highly efficient detector system and a low-energy Li beam. The results are much improved both in statistics and precisions, and show smaller cross sections than those of previous measurements by a factor of more than 2 in the low-energy region of E 1.5 MeV. A resonance-like structure is found at around E = 0.85 MeV.

Production of a low-energy radioactive nuclear beam with high purity using JAERI-RMS

Ishiyama, Hironobu*; Ishikawa, Tomoko*; Hashimoto, Takashi; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Miyatake, Hiroari; Tanaka, Masahiko*; Fuchi, Yoshihide*; Yoshikawa, Nobuharu*; et al.

Nuclear Instruments and Methods in Physics Research A, 560(2), p.366 - 372, 2006/05

https://doi.org/10.1016/j.nima.2005.12.244

Thanks to the nature of inverse transfer-reactions, low-energy radioactive nuclear beams in light neutron-rich region were produced. The mass-separation and velocity-separation of the JAERI recoil mass-separator help to form high purity beams. The beams of Li, B, and N-RNBs are utilized to the experiments, so far, with those beam intensities and purities of 1.410 pps and 99, 7.810 pps and 98, and 4.710 pps and 98.5, respectively.

Measurement of self-diffusion coefficients in Li ionic conductors by using the short-lived radiotracer of Li

Jeong, S.-C.*; Katayama, Ichiro*; Kawakami, Hirokane*; Watanabe, Yutaka*; Ishiyama, Hironobu*; Imai, Nobuaki*; Hirayama, Yoshikazu*; Miyatake, Hiroari; Sataka, Masao; Okayasu, Satoru; et al.

Journal of Phase Equilibria and Diffusion, 26(5), p.472 - 476, 2005/09

https://doi.org/10.1007/s11669-005-0037-0

Authors developed a radiotracer method for diffusion studies in solids. The experimental test was performed by the measurement of the diffusion coefficients of Li in a sample of the compound LiAl using an -emitting radiotracer of Li(T = 0.84 s). It was found that the time-dependent yields of the alpha particles from the diffusing 8Li that was initially implanted in the sample could be used as a measure of the diffusivity of the tracer in a nondestructive way. The method was applied to measure the self-diffusion coefficients of Li in LiGa, and for investigating how the Li diffusion in the Li ionic conductors is affected by the concentration of atomic defects.

Measurement of diffusion coefficients in solids by the short-lived radioactive beam of Li

Jeong, S.-C.*; Katayama, Ichiro*; Kawakami, Hirokane*; Watanabe, Yutaka*; Ishiyama, Hironobu*; Miyatake, Hiroari*; Sataka, Masao; Okayasu, Satoru; Sugai, Hiroyuki; Ichikawa, Shinichi; et al.

Nuclear Instruments and Methods in Physics Research B, 230(1-4), p.596 - 600, 2005/04

https://doi.org/10.1016/j.nimb.2004.12.107

no abstracts in English