Structural Changes in Molten Vb and VIb Metals and Ultra-Sound Propagation.

我们用这笔赠款更新了一个选通射频放大器，并建立了一个稳定的超声测量装置，我们用它系统地测量了高温下各种熔融合金中的声速。为了补充超声测量，我们用伽马射线衰减法测量了密度。此外，我们推导出新的热力学关系，使阐明局部结构变化引起的浓度波动。在此期间，我们在国际知名期刊上发表了十篇论文。为了进行研究项目，我接受了C博士的审查。伯格曼在法国国家科学研究中心，马赛和F。Sommer于1998年在斯图加特的MPI上完成的。结构的变化，在砷碲系统：相图已被调查，通过检测的最小值的声速和/或热膨胀系数作为温度的函数。最小值已确认高达60 at.%的As。过渡点i ...更多信息 外推得到过冷熔融砷的结构变化为734 ± 6℃.在熔融的IIb-VI B体系中的结构变化：通过测量声速，已经表明熔融的CdTe具有非常稳定的结构，而熔融的HgTe在熔点附近经历连续的结构变化。确定了HgTe熔体的相变点.本文导出了二元混合物中结构变化与浓度涨落之间的热力学关系式：这种新的热力学关系式能够解释由局部结构变化引起的浓度涨落。本文应用于揭示熔融S-Te体系中环状双熔体相的起源，结构变化引起的浓度波动是生长高质量化合物半导体晶体的关键之一。我们计划通过测量高温下熔融化合物半导体的比热以及声速和密度来系统地研究这一现象。少

We have renewed a gated RF amplifier with the grant and set up a stable ultra-sonic measurement gear, with which we have measured systematically the velocity of sound in various molten alloys at high temperatures. To compliment the ultra-sound measurements, we have measured the density with the gamma-ray attenuation method. Further we have derived the new thermodynamic relations which enable to elucidate the concentration fluctuations induced by local structural changes. During the period of the grand, we have published ten papers in well-established international journals. To proceed the research project, I was reviewed by Dr. C. Bergman at CNRS, Marseille and Dr. F. Sommer at MPI, Stuttgart in 1998.Main results are1. Structural changes in the As-Te system : the phase diagram has been investigated by detecting a minimum in the sound velocity and/or the thermal expansion coefficient as a function of temperature. The minimum has been confirmed up to 60 at.% of As. The transition point i … More n the structural change in the super-cooled molten As has been determined to be 734 ± 6℃ by an extrapolation.2. Structural changes in the molten II b-VI b system : by measuring the sound velocity, it has been shown that the molten CdTe has very stable structure whereas the molten HgTe undergoes continuous structural changes around the melting point. The transition point in the molten HgTe has been determined.3. The thermodynamic relations connecting structural changes and concentration fluctuations in a binary mixture : the new thermodynamic relations which enable to elucidate the concentration fluctuations induced by local structural changes have been derived. Application has been made to show the origin of the looped two-melt phase in the molted S-Te system.The concentration fluctuations induced by structural changes are one of the key points to be clarified to grow high quality crystals of the compound semiconductors. We are planning to investigate systematically the phenomenon by measuring the specific heat as well as the sound velocity and density of molten compound semiconductors at high temperatures. Less