منابع مشابه
Diffusing acoustic wave spectroscopy.
We have developed a technique in ultrasonic correlation spectroscopy called diffusing acoustic wave spectroscopy (DAWS). In this technique, the motion of the scatterers (e.g., particles or inclusions) is determined from the temporal fluctuations of multiply scattered sound. In DAWS, the propagation of multiply scattered sound is described using the diffusion approximation, which allows the auto...
متن کاملCryogenic resonant acoustic spectroscopy of bulk materials (CRA spectroscopy).
The capability to measure Q factors at cryogenic temperatures enhances the ability to study relaxation processes in solids. Here we present a high-precision cryogenic setup with the ability to measure Q factors of at least 10(9). This level of sensitivity offers new potential for analyzing relaxation processes in solids and for correlating mode shape and relaxation strength. Our improved method...
متن کاملAcoustic Spectroscopy of Superfluid He in Aerogel
We have designed an experiment to study the role of global anisotropic quasiparticle scattering on the dirty aerogel superfluid He system. We observe significant regions of two stable phases at temperatures below the superfluid transition at a pressure of 25 bar for a 98% aerogel.
متن کاملAcoustic Spectroscopy of Superfluid 3He in Aerogel
N. Mulders Department of Physics and Astronomy, University of Delaware, 223 Sharp Laboratory, Newark, Delaware 19716 (Received 21 December 1998) Liquid 3He in 98%-porous aerogel simultaneously possesses properties of a disordered p-wave superfluid and an elastic solid. We have observed two sound modes of superfluid 3He in aerogel. The first (fast) sound is a compression wave, and the second (sl...
متن کاملTemperature-dependent diffusing acoustic wave spectroscopy with resonant scatterers.
The influence of a slight temperature change on the correlation of multiply scattered acoustic waves is studied, and experimental results are discussed. The technique presented here, similar to diffusing-acoustic-wave spectroscopy, is based on the sensitivity of a multiply scattering medium to a slight change. Ultrasonic waves around 3 MHz are transmitted through a sample made of steel rods in ...
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ژورنال
عنوان ژورنال: The Journal of the Acoustical Society of America
سال: 1981
ISSN: 0001-4966
DOI: 10.1121/1.2018763