反演非球形粒子光学常数的理论建模

DETERMINATION OF THE OPTICAL CONSTANTS OF NON-SPHERICAL PARTICLES

本文基于完整的辐射传输方程,结合T矩阵法和K-K关系式,建立反演非球形粒子光学常数(复折射率)的理论模型。首先以椭球粒子为例,分析了非球形粒子光学常数反演模型的适用范围,重点分析了不同尺度参数下椭球粒子的单值性和多值性问题;然后以非球形煤灰粒子为例,采用MC法进行正问题计算,所得的光谱透射率作为"实验测量值",采用本文模型进行反演,得到较好的反演结果,充分说明了本文所建立的反演模型的可行性,同时分析了测量误差对实验结果的影响。

Based on the complete radiative transfer equation, an inverse model has been developed to determine the optical constants of non-spherical particles. Combined with the T-Matrix theory and Kramers-Kronig （K-K） relations, the complex refractive indices of non-spherical particle are retrieved. The application range of the inverse model is investigated firstly, and the unique value range and multi-value range are thoroughly discussed. In order to validate the present model, the optical constants of the ellipsoidal fly-ash particles available in the references are selected as the ‘true values＇, and the direct simulation of transmittivity in one-dimensional （1D） slab by Monte Carlo method are regarded as the ‘experimental values＇. Good agreement is obtained between the retrieved optical constants and the known ‘true value＇. The influence of measurement error on the inverse results is also investigated.