Shliomis Mark, Mond Michael, Morozov Konstantin
Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel.
Phys Rev Lett. 2008 Aug 15;101(7):074505. doi: 10.1103/PhysRevLett.101.074505.
The absorption of acoustic energy by internal degrees of freedom of short chains is proposed as a new viable mechanism of ultrasound attenuation in ferrofluids. It is demonstrated that even though the volume fraction of the chains may be quite small, such an effect may reach the order of magnitude of viscous damping. In addition, by investigating the statistical properties of dimers in ferrofluids, it is shown that an applied magnetic field modifies the sound attenuation in a highly anisotropic manner. The proposed mechanism provides new insight into the fundamental issue of colloidal response, and, in particular, may lead to its utilization in novel experimental concepts.
短链内部自由度对声能的吸收被认为是铁磁流体中超声衰减的一种新的可行机制。结果表明，尽管链的体积分数可能相当小，但这种效应可能达到粘性阻尼的数量级。此外，通过研究铁磁流体中二聚体的统计特性，发现外加磁场以高度各向异性的方式改变声衰减。所提出的机制为胶体响应的基本问题提供了新的见解，特别是可能导致其在新型实验概念中的应用。
