单分散生物气溶胶光散射特性的计算与分析  

Computation and Analysis of Light Scattering by Monodisperse Biological Aerosols

作　　者：冯春霞[1,2] 黄立华[1] 周光超[1,2] 韩杰[1,2] 曾爱军[1] 赵永凯[1] 黄惠杰[1] 

机构地区：[1]中国科学院上海光学精密机械研究所,上海201800 [2]中国科学院研究生院,北京100049

出　　处：《中国激光》2010年第10期2592-2598,共7页Chinese Journal of Lasers

基　　金：国家科技重大专项(2008ZX10401)资助课题

摘　　要：基于回转长椭球模型与球形模型,采用T矩阵法,讨论了非球形气溶胶颗粒的形状对散射相函数的影响;计算了葡萄球菌、鼠疫耶尔森氏杆菌、土拉热杆菌、志贺杆菌及类鼻疽伯克霍尔德菌等5种单分散生物气溶胶颗粒Stokes散射矩阵中各元素的角度分布曲线,讨论了非球形颗粒的粒径和形状对不同矩阵元素的影响。对于等消光截面颗粒,颗粒形状的变化对前向小角度与侧向两个散射区域的散射相函数几乎无影响,可以用球形颗粒近似模拟;非球形气溶胶颗粒的F11(θ)在170°～180°内的积分与在0°～10°内的积分的比值随着纵横比的增大而增大,可以表征颗粒的形状。对于不同尺寸和形状的气溶胶颗粒,[F11(0°)-F11(5°)]/5随着等表面积球半径的增大而增大,F11(θ)在170°～180°内的积分与在0°～10°内的积分的比值以及F22(θ)/F11(θ)在30°～90°内的积分随着纵横比的增大而增大,这些特性可用以判断颗粒的尺寸和形状。研究结果为颗粒粒径及粒形测量仪器的设计以及空气中有害微生物的快速探测提供了依据。The T-matrix method is used numerically to calculate the light scattering patterns of monodisperse,randomly oriented,non-spherical biological aerosol particles based on prolate spheroidal and spherical models in order to obtain size and shape sensitive information.The shape dependence of the phase function for the biological aerosol particles is discussed.The angular distributions of light scattered by Staphylococcus,Yersinia pestis,Francisella tularensis,Shigella dysenteriae and Burkholderia pseudomallei are presented and the size and shape dependence of the scattering matrix elements are illustrated in detail.At the forward-and side-scattering angles,the phase function has little dependence on particle shape for particles with equal extinction cross-section.It indicates that spherical model can be used to model non-spherical particles at these regions.The ratio of integrated backward-scattering at 170°～180°of F11（θ） to integrated forward-scattering at 0°～10° increases with the increases of the aspect ratio for non-spherical particles,which can be used to characterize particle shape.For aerosols of different sizes and shapes,the forward-scattering steepness [F11（0°）-F11（5°）]/5 of F11（θ） increases with surface-equivalent radius,which provides theoretical basis for particle size detection.The ratio of integrated scattering at 170°～180°to integrated scattering at 0°～10°of F11（θ） as well as integrated scattering at 30°～90° of F22（θ）/F11（θ） increases with the aspect ratio,which can be used to determine the shape of particles.The study results in this paper provide a theoretical foundation to the design of particle size and shape analysis apparatus and the fast and effective detection of harmful biological micro-organisms in the air.

关 键 词：光散射 生物气溶胶 T矩阵 散射矩阵元素 纵横比 

分 类 号：O433.4[机械工程—光学工程]