Using the function between the porosity and the diffusion coefficient and frequency in the diffusionimpedance, the finite diffusion model evaluated the porosity.
有限扩散模型则利用孔隙率与扩散系数和频率间的函数关系测定；
2
The conductivity mechanism of this membrane was studied with A. C. impedance method, the experimental results prove that the impedance of the boundary is controlled by the diffusion process.