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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...

Electrostatic levitators have been around for more than 30 years and have become mature tools for the material science community. Originally developed as positioners for materials and fluid science experiments in space, they saw a myriad of offsprings throughout the world for ground-based research, not only in space agencies but also in governmental laboratories, in universities and in the industry. Electrostatic levitators eliminate any physical contact with a container allowing to process and study corrosive or high temperature materials in their solid or liquid phases. Moreover, heterogeneous contamination from the container being avoided, it is possible to reach and maintain supercooled and metastable phases. This, in turns, permits a host of fundamental and applied studies. The nucleation and solidification phenomena can be scrutinized, the atomic structure and dynamic of liquid and metastable phases can be probed and the physics of molten drops could be investigated. On a more applied standpoint, the measure of thermophysical properties and the synthesis of materials with new properties are also possible with current facilities. This paper first describes the principle of electrostatic levitation and retraces the development of various facilities throughout the world, focusing on the advances made by each research group. The capabilities of electrostatic levitation for materials processing and synthesis under different environments are then presented. The paper successively covers in length its contribution for the measurements of thermophysical properties and for fundamental studies using high energy particle beams. Finally, the outlook of electrostatic levitators and its attractiveness for space experiments in materials sciences are discussed.

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

大気球シンポジウム 平成25年度（2013年11月14-15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), Balloon Symposium 2013 (November 14-15, 2013. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan, 著者人数: 18名, 資料番号: SA6000065026, レポート番号: isas13-sbs-026

A spectral emissivity measurement system combined with an electrostatic levitator was developed for high-temperature melts. The radiation intensity from a high-temperature sample was measured with a multichannel photospectrometer (MCPD) over the 700?1000?nm spectral range, while a Fourier transform infrared spectrometer (FTIR) measured the radiation over the 1.1?6??m interval. These spectrometers were calibrated with a blackbody radiation furnace, and the spectral hemispherical emissivity was calculated. The system's capability was evaluated with molten zirconium samples. The spectral hemispherical emissivity of molten zirconium showed a negative wavelength dependence and an almost constant variation over the 1850?2210?K temperature range. The total hemispherical emissivity of zirconium calculated by integrating the spectral hemispherical emissivity was found to be around 0.32, which showed good agreement with the literature values. The constant pressure heat capacity of molten zirconium at melting temperature was calculated to be 40.9 J mol?1?K?1.

Metallic liquid silicon at 1787K is investigated using x-ray Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in liquid silicon and provide support for the occurrence of theoretically predicted liquid-liquid phase transition in supercooled liquid states. The population of covalent bond pairs in liquid silicon is estimated to be 17% via a maximally-localized Wannier function analysis. Compton scattering is shown to be a sensitive probe of bonding effects in the liquid state., 5pages, 3 postscript figures

Accepted: 2011-06-30, 資料番号: SA1003078000

The electrostatic levitation furnace (ELF) for the International Space Station (ISS) has been developed and sent to the ISS. The main target of the furnace are oxide samples, which are difficult to levitate in 1-G. Thermophysical properties such as density, surface tension, and viscosity of molten oxides at high temperature will be measured using microgravity condition in the ISS. In this paper, the ISS-ELF and the first ISS experiment (thermophysical property measurement of some oxide materials) are introduced., 著者名の誤記: WATANEBE, 形態: カラー図版あり, The Clerical error of an author's name: WATANEBE, Physical characteristics: Original contains color illustrations, 資料番号: DS1540453000

The Electrostatic Levitation Furnace (ELF) is one of the experiment facilities for materials science, which will be on board Japanese Experiment Module “Kibo” of the International Space Station (ISS) in 2015. Since JAXA decided twenty years ago that ISS levitation furnace control method should be Coulomb force, we continued further research experiments and development of ground models. In 2011, JAXA has proceeded to the development phase of ELF and we are now ready to finish the development of ELF. JAXA plans to study thermophysical properties of many kinds of the oxides which cannot be measured on earth. In addition, creation of new materials is another objective of space experiments using ELF. Both is expected to contribute to a new discovery of scientific research and industrial applications. This paper shows the overview of ELF including the history of design concept., Accepted: 2015-01-19, 資料番号: PA1510046000

第28回宇宙利用シンポジウム (2012年1月23-24日. 日本学術会議), 港区, 東京都, Space Utilization Research (January 23-24, 2012. Science Council of Japan), Minato-ku, Tokyo Japan, 著者人数: 16名, 資料番号: SA6000032029, レポート番号: M29

Accepted: 2014-09-24, 資料番号: SA1140204000

資料番号: SA1005049000

Accepted: 2013-05-01, 資料番号: SA1004492000

Viscosities of several refractory metals (titanium, nickel, zirconium, niobium, ruthenium, rhodium, hafnium, iridium and platinum) and terbium have been measured by the oscillation drop method with an improved procedure. The measured data were less scattered than our previous measurements. Viscosities at their melting temperatures showed good agreement with literature values and some predicted values.

資料番号: PAIS08054000

Recent theoretical works have predicted that quasicrystals (QCs) have conspicuous fine electronic structures near the Fermi level (EF); the density of states (DOS) consists of sharp peaks and deep valleys with several lOmeV intervals, which is often called spiky structures. These fine electronic structures are believed to explain the extremely high resistivity of QCs. However, no experiment of observing the fine structures has succeeded for more than ten years. Wehave investigated the DOS around EF on icosahedral (i-)AlCuFe, i-AlPdMn, and decagonal (d-)AlCuCo quasicrystals by break junction tunneling spectroscopy at 4.2K and have observed clear peaks of 3.3 ~ 125mV width near EF. Each peak can be expressed by the probability distribution of the narrow energy gaps that are similar to BCS gaps. This is the first direct experimental result that confirms the predicted spiky structures existing in the vicinity of EF.