ANOMALOUS DIFFUSION DUE TO OBSTACLES - A MONTE-CARLO STUDY
ANOMALOUS DIFFUSION DUE TO OBSTACLES - A MONTE-CARLO STUDY
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DOI：
10.1016/s0006-3495(94)80789-1
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发表时间：
1994-02-01
影响因子：
3.4
通讯作者：
SAXTON, MJ
中科院分区：
文献类型：
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作者：
SAXTON, MJ
在正常的横向扩散中，扩散物质的均方位移与时间成正比。但在无序系统中，可能会发生反常扩散，其中均方位移与时间的其他幂成正比。在存在中等浓度障碍物的情况下，短距离内扩散是异常的，长距离内扩散是正常的。蒙特卡罗计算用于表征零和渗透阈值之间障碍物浓度的异常扩散。当障碍物浓度接近渗透阈值时，扩散在较长距离内变得更加异常；反常扩散指数和交叉长度均增加。交叉长度和时间表明在给定的实验中是否可以观察到异常扩散。
In normal lateral diffusion, the mean-square displacement of the diffusing species is proportional to time. But in disordered systems anomalous diffusion may occur, in which the mean-square displacement is proportional to some other power of time. In the presence of moderate concentrations of obstacles, diffusion is anomalous over short distances and normal over long distances. Monte Carlo calculations are used to characterize anomalous diffusion for obstacle concentrations between zero and the percolation threshold. As the obstacle concentration approaches the percolation threshold, diffusion becomes more anomalous over longer distances; the anomalous diffusion exponent and the crossover length both increase. The crossover length and time show whether anomalous diffusion can be observed in a,given experiment.