【作者】 王旭；

【导师】 徐强；

【作者基本信息】 西安电子科技大学 ， 光学， 2017， 硕士

【摘要】 本文主要研究了雾霾组分气溶胶粒子对平面波/波束的散射特性。其中雾霾组分主要包括硫酸铵、硫酸、硝酸铵和碳元素。散射特性的研究主要包括散射相函数、散射强度和微分散射截面随散射角的变化以及消光效率因子、散射效率因子和吸收效率因子随粒子尺寸参数的变化问题。主要工作成果如下:1.首先基于Mie理论研究了均匀球形和分层球形雾霾组分气溶胶粒子对平面波的散射特性,并比较了均匀球与含水分层球粒子散射特性的差异。然后利用T矩阵方法研究了均匀旋转对称椭球、圆柱体和切比雪夫雾霾组分气溶胶粒子对平面波的散射特性。将椭球粒子等效成相同体积的球形粒子计算其散射特性,并与椭球粒子的散射特性进行比较,得出在粒子半径与入射波波长相当的情况下,当旋转对称椭球的轴比接近1时,椭球可以等效成球形来计算其散射特性,而当旋转椭球接近于针形时,则不能等效成球形粒子来计算散射特性。最后还比较了旋转对称形粒子的形状对散射特性的影响。2.采用广义多球Mie理论(GMM)研究了团簇雾霾组分气溶胶粒子对平面波的散射特性,并比较了同组分团簇粒子与混合组分团簇粒子散射特性的差异以及相同团簇入射波方向不同时,团簇散射特性的差异。并使用广义多球Mie理论数值计算了扩展限制凝聚模型(DLA)理论所编写软件产生的凝聚分形团簇体的散射特性,分析比较了入射波方向和凝聚团簇组分对凝聚团簇散射特性的影响。3.使用广义Mie理论(GLMT)研究了均匀球和含水层分层球形雾霾组分气溶胶粒子对有形波束的散射特性,并比较了均匀球与含水分层球雾霾组分气溶胶粒子的散射特性的差异。(1)基于广义Mie理论原理中的区域近似方法给出了高斯波束波束因子的表达式。编写了数值仿真计算均匀球和分层球粒子与高斯波束作用散射特性的程序。比较了高斯波束和平面波与雾霾组分均匀球形和含水的分层球形气溶胶粒子相互作用散射特性的差异。(2)采用广义Mie理论中的计算波束因子的积分局部近似方法推导了贝塞尔涡旋波束的波束因子表达式。基于以上的推导编写了数值计算均匀球与分层球粒子散射特性的程序,通过与参考文献零阶贝塞尔涡旋波束与球形粒子作用散射特性的比较,证明了所编程序的正确性。并研究了不同拓扑荷数的贝塞尔涡旋波束与均匀球和含水分层球霾组分气溶胶粒子作用的散射特性。(3)使用角谱法推导出了拉盖尔高斯波束空间直角坐标系下电磁场的表达式,采用积分局部近似方法推导了拉盖尔高斯波束与球形粒子散射的波束因子表达式,并编写了拉盖尔高斯波束与球形粒子散射的仿真程序,通过零阶拉盖尔高斯波束和x轴方向极化的高斯波束与球形粒子相互作用散射特性的比较,验证了所编写程序的正确性。最后研究了不同拓扑荷数的拉盖尔高斯波束与均匀球和含水分层球霾组分气溶胶粒子作用散射特性变化的差异。更多还原

【Abstract】 In this dissertation,the scattering properties of aerosol particles illuminated with a plane wave/shaped beam are studied.The haze particles mainly includes ammonium sulfate,sulfuric acid,ammonium nitrate and carbon particles.The research of scattering characteristics mainly includes that scattering phase function,scattering intensity and differential scattering cross section change with the scattering angle,and that the extinction efficiency factor,scattering efficiency factor and absorption efficiency factor change with the size parameters of particle.The main results are as follows: 1.Based on Mie theory,the scattering properties of homogeneous spherical and water-containing stratified spherical aerosol particles of haze illuminated with plane wave are studied,and their difference were compared.And then the scattering properties of the aerosol particles of haze with homogeneous rotationally symmetric ellipsoid,cylinder and Chebyshev shapes illuminated by a plane wave were studied by using the T matrix method.The scattering properties of the sphere particle are compared with the scattering properties of spheroidal particle.It is concluded that the spheroidal particle can be equivalent to the sphere particle when the axis ratio of the spheroidal is close to 1,and when the rotation ellipsoid particles is close to the needle shape,it can’t be equivalent to the sphere particles to calculate the scattering properties.Finally,the scattering properties of the different shapes of the rotationally symmetric particles are compared.2.The scattering properties of cluster aerosol particles of haze illuminated by plane waves were studied by generalized multi-particles Mie theory(GMM).The scattering properties of single component cluster and mixtures component cluster are compared.And the scattering properties of the cluster illuminated by plane waves with different incident direction are compared.And the scattering properties of the aggregation fractal clusters are calculated by using the generalized multi-particles Mie theory(GMM),there clusters are produced by the software of the diffusion limited aggregation(DLA)model.The effect of the incident wave direction and the aggregation fractal cluster component on the scattering properties are analyzed and compared.3.The scattering properties of homogeneous spherical and water-containing stratified spherical aerosol particles of haze illuminated by shaped beam are studied by using generalized Lorenz-Mie theory(GLMT),and their difference were compared.(1)Based on the localized approximation method in generalized Lorenz-Mie theory,the expression of Gaussian beam shaped coefficients is given.A program for numerically calculating the scattering properties of homogeneous spherical and stratified spherical particles illuminated by Gaussian beams is designed.The difference of the scattering properties of homogeneous spherical and water-containing stratified spherical aerosol particles of haze illuminated by plane wave and Gaussian beam are compared.(2)The expression of beam shaped coefficients of the Bessel vortex beam is deduced by the integral localized approximation method in the generalized Lorenz-Mie theory.Based on the above derivation,a program for numerically calculating the scattering properties of homogeneous spherical and stratified spherical particles illuminated by Bessel vortex beams is designed,The differential scattering cross section changing with the scattering angle of a spherical particle illuminated by the zero-order Bessel vortex beam are compared with the results of the references,and the correctness of the program is proved.The scattering properties of homogeneous spherical and water-containing stratified spherical aerosol particles illuminated by different topological charge Bessel vortex beams are studied.(3)The expression of the electromagnetic field of the Laguerre Gaussian beam in the space Cartesian coordinate system is deduced by using the angular spectrum method.The expression of the beam shaped coefficients of a spherical particle illuminated by Laguerre Gaussian beam is deduced by the integral localized approximation method.A simulation program for numerically calculating the scattering properties of spherical particles illuminated by Laguerre Gaussian beam is designed.The correctness of the simulation program is verified by comparing the scattering properties of homogeneous spherical particles illuminated by zero order Laguerre Gauss beam with x axis polarized Gauss beam.In the end,the scattering properties of the homogeneous spherical and water-containing stratified spherical aerosol particles illuminated by different topological charge Laguerre gauss beams are studied.更多还原