Gittings A S, Durian D J
Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2008 Dec;78(6 Pt 2):066313. doi: 10.1103/PhysRevE.78.066313. Epub 2008 Dec 23.
We use speckle-visibility spectroscopy to measure the time dependence of bubble rearrangement events that are driven by coarsening in an aqueous foam. This technique gives the time trace for the average scattering site speed within a prescribed volume of the sample. Results are analyzed in terms of distributions of event times, event speeds, and event displacements. The distribution of rest times between successive events is also measured; comparison with diffusing-wave spectroscopy results shows that the spatial structure of a typical event consists of a core of only a few bubbles which undergo topology change plus a surrounding shell of bubbles which shift by an amount that decays to one wavelength at four to five bubbles away. No correlations are found between the durations, speeds, and rest times between successive events.
我们使用散斑可见光谱法来测量由水性泡沫粗化驱动的气泡重排事件的时间依赖性。该技术给出了样品规定体积内平均散射位点速度的时间轨迹。根据事件时间、事件速度和事件位移的分布对结果进行分析。还测量了连续事件之间的静止时间分布；与扩散波光谱结果的比较表明，典型事件的空间结构由仅几个经历拓扑变化的气泡核心加上周围的气泡壳组成，气泡壳移动的量在四到五个气泡远处衰减到一个波长。连续事件之间的持续时间、速度和静止时间之间未发现相关性。
