On the basis of fractal theory and n-dimension fractal browian movement, this paper proposed to use fractal dimension to describe the geometric characteistics of the friction surface and proved, it is a parameter that describes the state of chaos in the friction surface.

Study on dosage control by flocs fractal dimension;

Determination of fractal dimensions of silicon dioxide xerogel by means of gas-adsorption;

Study of fractal dimension and its effect on specific heat capacity of coal or chars;

Relation between compressive strength and fractal dimensions of jointed rock-mass;

Dynamic change of particle size and fractal dimensions of polyferric chloride-humic acid (PFC-HA) flocs;

Properties of fractal dimensions of albic soil for radix ginseng culture;

The fractional dimension of crack section was measured and analyzed.

The fractional characteristics of granularity distribution for sinter of Tangshan stainless steel corporation with different basicity were investigated by fractional theory and their fractional dimensions were worked out by calculation.

The spatial distributions of porosity and fractional dimension of autotrophic and heterotrophic/autotrophic biofilms applied by direct current in the range of 0～25 A/m 2 were investigated by using the micro slicing technique and image analysis.

All those studies need deal with the estimation of the fractal-dimension.

In this paper, the features of fractured media and rock matrix in fractal dual porosity reservoir model are describes with fractal dimension (describing geometric features) and fractal index(depicting connectivity of a fractal fluid flow network).