Transmission of sound at the liquid-solid interface of helium : a new probe of melting kinetics
Transmission of sound at the liquid-solid interface of helium : a new probe of melting kinetics
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氦液固界面的声音传输：熔化动力学的新探针
DOI：
10.1051/jphys:01980004107070100
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
P. Nozières
中科院分区：
文献类型：
--
作者：
B. Castaing;P. Nozières
2014一个入射声波产生一个交流化学势的不连续性，039403 BC在液-固界面。如果熔化速度足够快，它就会对这种激发作出反应。我们表明，在量子系统中，热量可以通过对流疏散，这样的交流。熔化确实发生。它可能会导致声音传输的急剧下降，并导致从第一声音到第二声音的转换机制。我们分析了这种影响，我们提出了一个实验，应该让访问熔化的动力学时，它是太快，直流方法观察。J. Physique 41（1980）701-706 JUILLET 1980，分类物理学摘要67.00在普通材料中，熔化和晶体生长是原子尺度上的缓慢过程。首先，必须处理相变潜热，它通常是动力学的控制因素。其次，增长本身取决于界面的性质[1]。如果后者是尖锐和光滑的，则新层的成核是控制步骤;它发生在表面缺陷上（参见。位错上的螺旋生长）并且该过程是缓慢的。只有当界面粗糙时，才会发生快速生长，并自发形成许多台阶和扭结：然后每一层都在连续生长。这种粗糙的表面是由在晶体的平衡形状中没有小平面来表示的。
2014 An incoming acoustic wave produces an a.c. discontinuity of chemical potential, 039403BC at a liquid-solid interface. If melting is fast enough, it responds to such an excitation. We show that in quantum systems, in which heat can be evacuated via convection, such an a.c. melting does occur. It may give rise to a spectacular decrease in sound transmission, and to a conversion mechanism from first to second sound. We analyse that effect, and we propose an experiment that should give access to the kinetics of melting when it is too fast to be observed by d.c. methods. J. Physique 41 (1980) 701-706 JUILLET 1980, Classification Physics Abstracts 67.00 In ordinary materials, melting and crystal growth are slow processes on an atomic scale. First of all, one must dispose of the latent heat of transformation, which usually is the controlling factor of the kinetics. Second, the growth itself depends on the nature of the interface [1]. If the latter is sharp and smooth, the nucleation of a new layer is the controlling step ; it occurs on surface defects (cf. spiral growth on dislocations) and the process is slow. Fast growth can only occur if the interface is rough, with spontaneous formation of many steps and kinks : then each layer grows continuously. Such a rough surface is signalled by the absence of facets in the equilibrium shape of the crystals.