Han Y, Alsayed A M, Nobili M, Zhang J, Lubensky T C, Yodh A G
Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104, USA.
Science. 2006 Oct 27;314(5799):626-30. doi: 10.1126/science.1130146.
We studied the Brownian motion of isolated ellipsoidal particles in water confined to two dimensions and elucidated the effects of coupling between rotational and translational motion. By using digital video microscopy, we quantified the crossover from short-time anisotropic to long-time isotropic diffusion and directly measured probability distributions functions for displacements. We confirmed and interpreted our measurements by using Langevin theory and numerical simulations. Our theory and observations provide insights into fundamental diffusive processes, which are potentially useful for understanding transport in membranes and for understanding the motions of anisotropic macromolecules.
我们研究了限制在二维空间的水中孤立椭球形颗粒的布朗运动，并阐明了旋转和平移运动之间耦合的影响。通过使用数字视频显微镜，我们量化了从短时间各向异性扩散到长时间各向同性扩散的转变，并直接测量了位移的概率分布函数。我们通过使用朗之万理论和数值模拟来证实和解释我们的测量结果。我们的理论和观察结果为基本扩散过程提供了见解，这对于理解膜中的传输以及各向异性大分子的运动可能是有用的。
