月壤等效介质模型及应用

发布时间：2018-06-02 06:13

本文选题：月壤 + 介电常数　；参考：《吉林大学》2015年硕士论文

【摘要】：月球的表层物质月壤中富含稀有气体、钛铁矿、He-3等重要资源，反演月壤介电常数、探测月壤物质组成及结构等参数对月球资源的勘探开发与利用具有重要现实意义。而且，月壤参数与月球表面的暴露年龄及撞击坑年龄大小有着不可分割的联系，这给研究月表撞击历史和确定月球表面年龄工作也将会带来重大意义。通过对经典的Maxwell-Garnett与Bruggeman等效介质理论以及考虑颗粒间相互作用的Maxwell-Garnett理论进行公式推导，并分析各个理论的适用性，在此基础上，建立了两个适用于月壤的等效介质模型，用于研究月壤的介电常数与其组成矿物成分及颗粒大小的关系。为验证模型在模拟月壤介电常数方面的准确性，根据地面玄武岩（火山岩）不同岩相和产状，在吉林省辉南、黑龙江阿尔山、黑龙江镜泊湖和黑龙江五大连池以及河北张家口和内蒙古的锡林浩特地区，采集了不同岩相和产状的火山岩样品，将其加工成粉末状来模拟月壤样品。利用实验室的矢量网络分析仪，选用同轴探头方法对200目的火山岩样品及80目~200目等不同粒径下的单斜辉石、斜长石粉末样品，以及两种矿物不同体积分数混合所得到混合样品的介电常数实部进行测量。对比分析实验测得的实际值与两个月壤等效介质模型模拟得到的混合物等效介电常数，发现基于Maxwell-Garnett理论模拟的值较实测值偏小，基于强化Maxwell-Garnett理论的模型模拟得到的值偏大。而基于Bruggeman理论的月壤等效介质模型与实测值相比误差很小，吻合度较高，适用于模拟月壤混合物的等效介电常数。在完成模型验证的基础上，模拟了月壤介电常数与粒径、物质组成及体积分数间的关系。得出颗粒粒径大小在0~150μm之间时，月壤的介电常数随着颗粒粒径的变大而变大，在150~1000μm区间时，，介电常数基本保持不变；月壤中矿物对等效介电常数的贡献值与其介电常数值大小呈正相关关系，与介电常数最大矿物的体积分数呈正相关系，介电常数最小矿物的体积分数呈负相关关系。在对月壤等效介质模型实际应用上，以嫦娥三号测月雷达数据为依据，对其第二通道A、B天线获得的雷达波数据进行拼接、冗余数据删除、数字滤波等处理。在此基础上，利用双天线时延法反演得到嫦娥三号月球车巡视区域下月壤的平均介电常数及月壤厚度。最后，依据月壤等效介质模型模拟得到的规律及反演得到的月壤介电常数，反演得到粒径大于150μm的月壤中钛铁矿的含量值范围为0~11.52%；橄榄石为0~56.85%；单斜辉石为0~76.88%；斜长石含量不小于23.11%。与Apollo和Luna采集的样品实际矿物分析结果相比，具有一定可信度。模拟反演月壤矿物含量工作也为今后月球探测及月壤资源开发带来帮助。
[Abstract]:The lunar soil is rich in rare gases. It is very important for the exploration and utilization of lunar resources to retrieve the permittivity of lunar soil and to detect the composition and structure of lunar soil. Furthermore, the lunar soil parameters are inextricably related to the exposure age of the lunar surface and the age of the crater, which will also bring great significance to the study of the impact history of the lunar surface and the determination of the age of the lunar surface. Based on the formula derivation of the classical Maxwell-Garnett and Bruggeman equivalent medium theory and the Maxwell-Garnett theory considering the interaction between particles, and the analysis of the applicability of each theory, two equivalent media models suitable for lunar soil are established. It is used to study the relationship between the dielectric constant of lunar soil and its mineral composition and particle size. In order to verify the accuracy of the model in simulating the dielectric constant of lunar soil, according to the different lithofacies and occurrence of surface basalt (volcanic rock), in Huinan, Jilin Province, Alshan, Heilongjiang, Samples of volcanic rocks with different lithofacies and occurrence were collected from Jingbo Lake and Wudalianchi of Heilongjiang and Zhangjiakou of Hebei and Xilinhaote of Inner Mongolia. The samples were processed into powder to simulate lunar soil. By using a vector network analyzer in the laboratory, a coaxial probe method was used for the determination of 200 target volcanic samples and 80 mesh / 200 mesh samples of clinopyroxene and plagioclase powder. The real part of the dielectric constant of the mixed samples obtained by mixing the two minerals with different volume fraction was measured. By comparing the actual values measured by experiments with the equivalent dielectric constants of mixtures simulated by the equivalent media model of two lunar soils, it is found that the values based on Maxwell-Garnett theory simulation are smaller than those measured, and the values obtained by model simulation based on enhanced Maxwell-Garnett theory are larger than those based on Maxwell-Garnett theory. The equivalent medium model of lunar soil based on Bruggeman's theory is suitable for simulating the equivalent dielectric constant of lunar soil mixture because of its small error and high consistency compared with the measured data. Based on the model verification, the relationship between the permittivity of lunar soil and particle size, material composition and volume fraction was simulated. The results show that when the particle size is between 0 and 150 渭 m, the dielectric constant of lunar soil increases with the increase of particle size, and the dielectric constant remains basically unchanged in the range of 150 渭 m to 1000 渭 m. The contribution of minerals to the equivalent dielectric constant in lunar soil is positively correlated with its dielectric constant value, positively correlated with the volume fraction of the maximum dielectric constant mineral, and negatively correlated with the volume fraction of the minimum dielectric constant mineral. In the practical application of the lunar soil equivalent medium model, based on the lunar radar data of Chang'e 3, the radar wave data obtained from its second channel AHB antenna are spliced, redundant data deleted, digital filtering and so on. On this basis, the average permittivity and the thickness of lunar soil under the lunar rover of Chang 'e-3 are obtained by using the method of double antenna delay. Finally, according to the simulation of the equivalent medium model of lunar soil and the permittivity of lunar soil obtained by inversion, the content of ilmenite in lunar soil larger than 150 渭 m is obtained in the range of 0 ~ 11.52, olivine is 0, 56.85, clinopyroxene is 0 ~ 76.88, and plagioclase is no less than 23.11. Compared with the actual mineral analysis results of samples collected by Apollo and Luna, it has some reliability. The simulated inversion of lunar soil mineral content will also be helpful for lunar exploration and the development of lunar soil resources in the future.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P184.5

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