消光法粒度测量中折射率反演问题研究  

Inversion of Refractive Index in Particle Sizing by Multi-spectral Light Extinction Method

作　　者：徐峰[1] 蔡小舒[1] 苏明旭[1] 任宽芳[2] 

机构地区：[1]上海理工大学颗粒与两相流测量技术研究所IPTFM,上海200093 [2]法国国家科研中心空间热化学联合研究所CORIA,法国鲁昂76801

出　　处：《中国粉体技术》2005年第3期1-3,共3页China Powder Science and Technology

基　　金：上海市科委纳米计划(编号:0450nm029);法国驻华使馆(4B2-007)资助

摘　　要：利用多波长消光法,在已知粒度分布前提下,采用遗传算法对折射率进行了反演。相比于传统的优化方法通常获得的局部最优解,该算法获得的折射率结果逼近全局最优解。反演采用的波长数目和颗粒单分散性的优劣影响解的可靠性。尽量多地获得透射谱信息以及增大颗粒系的分散性可以是测量结果更准确。由于亚微米和纳米级颗粒的消光系数-折射率曲线的单值性关系比微米级颗粒更为明显,导致其目标函数的多峰分布程度得以降低,使反演的抗噪能力增强,折射率更易于获得。The genetic algorithm (GA) is employed to inverse the refractive index of a particulate system. The particle size distribution is provided to be known in advance. Compared with other traditional optimization methods, GA's results approach the global optimum solution instead of locals ones. The effect of GA is influenced a lot by the number of wavelength used for inversion as well as the dispersity of the particulate system. More information of the transmission spectrum is known and the better the particles are dispersed, the higher precision of the results can be achieved. Besides, since the monotonicity of extinction coefficient-refractive index curve for submicron level particles is more obvious than that for micrometer level ones, the extent of the multimodal distribution will be weakened and the inversion algorithm is more resistant to the measurement errors, which makes the inversion results more reliable.

关 键 词：颗粒测量 MIE散射 折射率 反演 

分 类 号：TH744[机械工程—光学工程]