Inversion Of Photo-Thermal Parameters Of Materials And Depth Profile Imaging

Both heat conduction and related inverse problems have an extensive application in practical engineering. So it is very important to study the heat conduction problems and inversion of photo-thermal parameters of materials. The main intents of this dissertation are hyperbolic heat conduction transient analysis and reconstruction of some photo-thermal parameters.At the beginning of the paper, a brief introduction to both IP(Inverse Problems) and IHCP(Inverse Heat Conduction Problems) is reported and the main work of this paper is listed. Then, we reconstruct the depth profile of heat source and optical absorption coefficient distribution by adopting parabolic heat conduction model and solving Green function. For the consideration of adaptability and stability of our method, we simulate the inversing result under noisy conditions. Thirdly, we analyze some factors that influence inversing quality and we also give some countermeasures. Especially to the thicker sample, we use the temperature spectra measured from both surfaces of a sample. Fourthly, through computation, we get the sensitivity formula of surface signal to heat source and optical absorption coefficient, and performed numerical analysis. Fifthly, delay-time transform is used to convert parabolic thermal model into a new one, which integrate all the distributing parameters into one. Through theoretical calculation and numerical simulation we reconstruct the depth profile of a kind of thermal parameters(i.e., Thermal conductivity, diffusivity and effusivity). In the last part, we use finite difference method to study the hyperbolic heat waves generated by pulsed laser, and we also compare it with the result which is simulated by using integration method.At the end of the dissertation, we make a conclusion and an expectation for the work that we have concerned.