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Because ice surfaces catalyze various key chemical reactions impacting nature and human life, the structure and dynamics of interfacial layers between water vapor and ice have been extensively debated with attention to the quasi-liquid layer. Other interfaces between liquid water and ice remain relatively underexplored, despite their importance and abundance on the Earth and icy extraterrestrial bodies. By in situ optical microscopy, we found that a high-density liquid layer, distinguishable from bulk water, formed at the interface between water and high-pressure ice III or VI, when they were grown or melted in a sapphire anvil cell. The liquid layer showed a bicontinuous pattern, indicating that immiscible waters with distinct structures were separated on the interfaces in a similar manner to liquid-liquid phase separation through spinodal decomposition. Our observations not only provide a novel opportunity to explore ice surfaces but also give insight into the two kinds of structured water.

著者人数: 15名, Accepted: 2020-02-11, 資料番号: SA1190184000

Accepted: 2015-12-15, 資料番号: SA1160353000

著者人数: 12名, Accepted: 2015-10-08, 資料番号: SA1150319000

This review briefl y describes the vacuum electrostatic levitation furnace developed by JAXA and the associated non-contact techniques used to measure the density, the surface tension and the viscosity of materials. The paper then presents a summary of the data taken with this facility in the equilibrium liquid and non-equilibrium liquid phases for the six platinum group metals (pgms): platinum, palladium, rhodium, iridium, ruthenium and osmium over wide temperature ranges that include undercooled and superheated phases. The presented data (density, surface tension and viscosity of Pt, Rh, Ir, Ru and Os and density of Pd) are compared with literature values.

Crystal–liquid interfacial free energy is important to understand in crystal study, for example, nucleation, crystal growth, and vitrification. Here, we report the nanosized nucleus-supercooled liquid interfacial free energy of early and late transition liquid metals using the electrostatic levitation (ESL) technique and classical homogeneous nucleation theory (CNT). For the estimation of the interfacial free energy, we obtained thermophysical parameters of the transition liquid metals (Ti, Fe, Ni, Zr, Nb, Rh, and Hf), such as hypercooling limit (ΔThyp), specific heat (Cp), total hemispherical emissivity (eT), and density (ρ). The estimated interfacial free energies of Ti, Ni, and Zr agreed well with a previous report having similar hypercooling limit and fusion enthalpy, while Fe, Nb, Rh, and Hf show different values from the report. This reflects the importance of accurate measurement of the two quantities. The obtained Turnbull’s coefficients (α) of the liquid metals is higher than 0.45. The interfacia...

Short duration microgravity experiments are useful tools for the development of experimental apparatus for microgravity researches. Parabolic flights have been frequently used for the development of the electrostatic levitation furnace (ELF) for the International Space Station (ISS). The history of ELF development and parabolic flight experiments conducted for its development are briefly described in this paper., 形態: 図版あり, Physical characteristics: Original contains illustrations, 資料番号: DS1440102000

Viscosities of tungsten, rhenium, osmium, tantalum, and molybdenum have been measured by the oscillation drop method with an improved procedure. The measured data exhibit less-scatter than our previous measurements. Viscosity at the melting temperature of the investigated metals showed a good agreement with literature values and some predicted values.

第30回宇宙環境利用シンポジウム (2016年1月19日-20日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)), 相模原市, 神奈川県, Space Utilization Research (January 19-20, 2016. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 15名, 資料番号: SA6000048024, レポート番号: G-20

Accepted: 2012-11-15, 資料番号: SA1004278000

Accepted: 2010-02-07, 資料番号: SA1000813000

To understand behavior of molten core materials is an urgent issue to investigate the progression of a core meltdown accident in nuclear power plants. Zirconium (Zr) based alloys have been widely used as nuclear fuel claddings and structural materials in the nuclear power plants. Since the typical atmosphere during most accident scenarios is steam, Zr liquid containing significant amount of O (Zr-O liquid alloys) will be generated in the case of the core meltdown accident. In this study we aim to provide thermophysical properties of Zr-O liquid alloys. To avoid a difficulty in measurement due to high melting point and high reactivity of Zr liquid, electrostatic levitation technique was employed for the measurement. Zr-O alloys with nominal compositions of Zr(0.9)O(0.1) and Zr(0.8)O(0.2) were prepared from powder Zr and ZrO2 by solid-state reaction. The oxygen composition was evaluated by thermogravimetric analysis. The measured viscosities of Zr-O liquids are higher than those of Zr liquid (experimental) and ZrO2 liquid (calculated), which indicates that the composition-dependent viscosity may have maxima in Zr-O liquids., 形態: カラー図版あり, Accepted: 2018-01-09, Physical characteristics: Original contains color illustrations, 資料番号: DS1740409000

Accepted: 2010-03-02, 資料番号: SA1002707000

高温融体内の原子の運動に関する実験的な知見は、融体の熱物性と構造の関係を理解する上で極めて重要である。我々は、高温融液の原子ダイナミクスの観察を目的として非弾性X線散乱用の小型の静電浮遊装置を開発し、融点および過冷却液体シリコンの動的構造因子を測定した。本装置を用いることにより液体シリコンのフォノンピークが明瞭に観察され、その分散関係が明らかになった。, The atomic dynamics in high temperature melts are essential information for the understanding of the relation between liquid structure and thermo-physical properties in liquid state. The small Electrostatic Levitation furnace, ESL, was developed for the inelastic X-ray scattering facility in SPring-8. The observation of dynamic liquid structure factor, S (Q, w) of normal and undercooled liquid silicon was performed. The phonon peak of S (Q, w) in the liquid silicon was clearly observed and its dispersion relation can be obtained., 資料番号: AA0063323004, レポート番号: JAXA-RR-06-015E

An electrostatic levitator was developed for the structural analysis of high-temperature and undercooled liquids by X-ray diffraction. The apparatus can be used to investigate the structure of metallic, semiconductor, and ceramic liquids. Samples of zirconium, silicon, and alumina in their liquid phases could be kept levitated for more than one hour with this apparatus. This was sufficiently long to perform a detailed analysis of the liquid structure by X-ray diffraction techniques., 資料番号: AA0063323003, レポート番号: JAXA-RR-06-015E

The atomic dynamics in high temperature melts are essential information for the understanding of the relation between liquid structure and thermo-physical properties in liquid state. The small Electrostatic Levitation furnace, ESL, was developed for the inelastic X-ray scattering facility in SPring-8. The observation of dynamic liquid structure factor, S(Q,w) of normal and undercooled liquid silicon was performed. The phonon peak of S(Q,w) in the liquid silicon was clearly observed and its dispersion relation can be obtained., 資料番号: AA0063349039

Spectral emissivity and constant heat capacities of molten metals (nickel, zirconium, rhodium, and niobium) at their melting temperatures were measured using containerless techniques. Samples were levitated in an electrostatic levitator and the radiation intensities from the molten samples were measured with spectrometers over a wide wavelength range. The spectrometers were calibrated with a blackbody radiation furnace and the spectral hemispherical emissivity was calculated. Then, the total hemispherical emissivity (ε(sub T)) was obtained by integrating the spectral emissivity over wavelength. Finally, constant pressure heat capacity was calculated using the data obtained from the cooling curve and ε(sub T)., 形態: カラー図版あり, Physical characteristics: Original contains color illustrations, 資料番号: DS1740259000

著者人数: 15名, 資料番号: SA1150061000

著者人数: 14名, Accepted: 2014-11-18, 資料番号: SA1004995000