Random walks and anomalous diffusion in two-component random media

The diffusion process in a random media consisting of two different components is studied by a random walk model. The latter is described by three parameters, namely, the fraction p of components, the ratio h of the diffusion coefficients in two components, and the parameter x defining a walker's jumps at the boundary. Depending on the values of these parameters the diffusion can be confined, normal, or anomalous (subdiffusion). The subdiffusion occurs, in particular, for h=0 (trapping model) and for x=0 (excluded volume model).