Nonlinear diffusion equation describing IP effect

Based on the electrochemical theory of IP effect, the coupled partial diffe rential equation describing the temporal and spatial variations in the conc entrations of ions can be written out by studying the patterns of the ions' motion on the interface. According to the structure of the electrical doub le layer and the stationary solution of the equations, we derive a nonlinea r diffusion equation supplemented by relevant initial and boundary values, and put forward a theoretical model of IP. We have obtained numerical solut ion in time and frequency domain respectively with the help of computer usi ng the difference approximation. These results revealed the induced polariz ation properties of minerals. The results calculated from this model prove that this theoretical model can describe the IP effect correctly in linear and nonlinear regions.