Shinji Kohara is the group leader of the quantum beam diffraction group in the Center for Basic Research on Materials (CBRM) at NIMS. He received his Ph.D. degree in 1998 from the Tokyo University of Science. In 1998, he was involved in the development of a dedicated high-energy X-ray diffractometer for disordered materials at the world’s largest synchrotron radiation facility, SPring-8. From 2001 to 2015, he worked there as a beamline scientist. Since 2015, he has been working at NIMS. His current research interests include the inorganic chemistry and materials science of glasses, liquids, and amorphous materials.30Determining the liquid structure is the first step in understanding the nature of glass-liquid transitions. High quality diffraction and density data are very important in obtaining a reliable structural model by modeling or simulation. In addition, precise knowledge of viscosity is essential in order for understanding the nature of glasses and liquids. However, it is difficult to obtain these data for oxides with high melting temperatures (Tm) in the liquid state, because the samples are easily contaminated by container materials or nucleated from the heterogeneous interface between the container and the liquid. To overcome such problems, we have developed levitation furnaces that can keep high-temperature liquids in place without any contact (see Fig. 1).The combination of quantum beam (X-ray and neutron) measurements and levitation techniques is a powerful approach to reveal the structure of high-temperature liquids, as well as of glasses with limited glass forming ability. In particular, the aerodynamic levitation technique is very useful for measuring diffraction data from oxide liquids, and preparing bulk oxide glasses with low glass forming ability. On the other hand, the electrostatic levitation furnace (ELF) is available in the international space station (ISS) KIBO for determining the density and viscosity of oxide liquids. We review scientific investigations of oxide glasses and high-temperature liquids considered by us over the past ten years [1–3].[1] S. Kohara et al., Nat. Commun. 5, 5892 (2014)[2] C. Koyama et al., NPG Asia Mater. 12, 43 (2020)[3] Y. Shuseki et al., J. Phys. Chem. A 128, 716 (2024)National Institute for Materials Science (NIMS)Fig. 1 Aerodynamically levitated La4Ti9O24 liquid (1800 ℃). The sample was levitated by dry air and heated by a CO2 laser. Abstract Structure and Thermophysical Properties of High-temperatureLevitated LiquidsShinji KoharaGroup Leader, Quantum Beam Diffraction Group,Center for Basic Research on Materials (CBRM),NIMS Talk: S1-7
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