This effect was investigated by using a generalized random resistor-network model. A random sequential packing model that was different to that of Roman and Yussouff was proposed. Computer simulations showed that there existed a maximum critical particle size above which the second critical concentration (at which the conductor-insulator transition occurred) would disappear. The first critical concentration, at which an interface percolation transition occurred could also disappear above the critical particle size. The numerical results were in good agreement with experimental results and with previous predictions.

G.M.Zhang: Physical Review B, 1996, 53[10], 6256-62