兰州大学机构库 >土木工程与力学学院
局部带电球形沙粒系统的微分散射截面和相移
Alternative TitleDifferential Scattering Cross Section and Phase Shift of Partially Charged Spherical Sand Particle System
汪亚龙
Thesis Advisor谢莉
2014-05-28
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword球形颗粒系统 电荷层介质 双层散射介质 局部带电 微分散射截面 面电荷密度 电导率 空间相位
Abstract已有理论和实验研究表明沙尘暴由于沙粒局部带电对入射电磁波造成不同程度的影响。本论文围绕沙粒局部带电对电磁波散射的过程及其局部带电沙尘系统的微分散射截面和相移开展研究,主要工作如下: 首先基于电磁波在介质中的传播性质,我们将沙粒表面电荷层和沙粒看作是一种分层散射介质,提出电磁波在局部带电沙粒中分层传播,即:当电磁波照射在不带电区域时,电磁波可穿越沙粒介质,部分电磁波发生散射之后再通过带电区域;当电磁波直接照射在带电区域时,电磁波只在带电区域内传播,发生散射等,因此电磁波通过局部带电沙粒时的散射特性与电磁波是否首先入射到电荷区域相关。 然后利用Lorenz-Mie理论求解出局部带电球形颗粒系统的微分散射截面及电磁波散射的空间相位,结果发现:沙粒带电对微分散射截面有着显著的影响,沙粒表面多余电荷增强了电磁波的散射;并且在考虑多次散射时的微分散射截面明显大于独立散射的微分散射截面。电磁波入射到球形沙粒表面会导致电磁波传播相位的变化,当沙粒表面局部带电时,相位随着带电量的增加而增大,并且相位会出现明显的跳跃式变化,其跳跃点与沙粒的面电荷分布角相关。
Other AbstractThe existing theoretical and experimental research found that the partially charged sand particles will influence the incident EM wave with varying degrees. This paper starts the research based on the scattering process of EM waves acted by partially charged sand particles and the differential scattering cross section and phase of partially charged sand particle system. The main work is as follows: Firstly, the surface charge layer and sand particles are treated as a kind of layered scattering media according to the propagation property of EM waves and the layered propagation mechanism of EM waves in the partially charged sand particles is put forward, namely: when the EM waves irradiate on the uncharged region, they can pass through the sand media, and then part of the EM waves go through the charged region after scattering; when the EM waves directly irradiate charged region, they propagate and scatter only in the charged region. Then, this paper derives the differential scattering cross section and phase of partially charged spherical sand particle system according to the generalized Lorenz-Mie theory and obtains the influence results of partially charged spherical sand particle system . The results show that: charged sand particles have a significant influence on the differential scattering cross section, which will be increased when the surface charge increase, indicating that the excess surface charge enhances the EM wave scattering; under the same condition.when the grains of sand on the surface of partial charged phase increases with the increase of charge. phase space is larger than the value of single scattering approximation when considering multiple scattering effects and charged sand particles will influence the critical distance of multiple scattering.
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Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226200
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
汪亚龙. 局部带电球形沙粒系统的微分散射截面和相移[D]. 兰州. 兰州大学,2014.
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