碳纳米管非均匀氢等离子体薄膜的微波吸收特性研究

发布时间：2018-05-26 11:14

本文选题：碳纳米管 + 非均匀氢等离子体　；参考：《南华大学》2015年硕士论文

【摘要】：现代军事隐身和民用微波防护对吸波材料提出了越来越高的要求。质量轻,力学性能好,具有特殊电磁性能的碳纳米管及其复合材料的合成,为吸波材料开辟了一个新的领域。碳纳米管具有良好的吸附储氢性能,在微波作用下,其高频电磁场能使碳纳米管中的氢气激发而产生氢等离子体。初步实验研究表明,碳纳米管氢等离子体是最具有应用前景的碳纳米管吸波材料。本课题组研究了碳纳米管均匀氢等离子体的微波吸收特性。实际上,碳纳米管氢等离子体是不均匀的,本文在已有成果的基础上,理论研究了等离子体密度分布和磁场强度对碳纳米管中氢等离子体微波吸收的影响,构建了碳纳米管非均匀氢等离子体薄膜介电特性的层状模型,运用转移矩阵法求解电磁波的传播方程,导出了碳纳米管中非均匀氢等离子体的微波衰减系数公式,数值计算了不同密度分布和不同磁场强度条件下的碳纳米管氢等离子体薄膜对微波的衰减系数。研究结果表明:氢等离子体的密度分布和外加磁场强度对其微波吸收有重要影响;按比例增大氢等离子体中自由电子密度的非均匀性时,微波衰减吸收系数增大,吸收峰向高频方向移动;随着外加磁场强度增大,碳纳米管氢等离子体薄膜的微波吸收峰向高频移动,入射电磁波在碳纳米管非均匀氢等离子体薄膜中的能量衰减大于30d B/cm的频宽增大,有利于微波吸收;数值结果与已获得的实验数据相吻合。结合本课题组以前的研究成果可知,只要适当控制碳纳米管中等离子体的自由电子密度、电子碰撞的有效频率和外加磁场强度,就能够实现碳纳米管中氢等离子体薄膜对微波的调谐吸收。本论文的研究目的是为碳纳米管氢等离子体应用于现代军事隐身和民用微波防护提供理论参考。
[Abstract]:Modern military stealth and civil microwave protection put forward higher and higher requirements for absorbing materials. The synthesis of carbon nanotubes and its composites with light weight, good mechanical properties and special electromagnetic properties opens up a new field for absorbing materials. Carbon nanotubes (CNTs) have good hydrogen adsorption and storage properties. The high frequency electromagnetic field of carbon nanotubes (CNTs) can excite hydrogen in carbon nanotubes and produce hydrogen plasma under microwave irradiation. The preliminary experimental results show that carbon nanotube hydrogen plasma is the most promising microwave absorbing material for carbon nanotubes. The microwave absorption characteristics of carbon nanotube homogeneous hydrogen plasma were studied. In fact, carbon nanotube hydrogen plasma is inhomogeneous. In this paper, the effects of plasma density distribution and magnetic field intensity on the microwave absorption of hydrogen plasma in carbon nanotubes are theoretically studied. A layered model of dielectric properties of carbon nanotubes (CNTs) inhomogeneous hydrogen plasma films was constructed. The microwave attenuation coefficient formula of carbon nanotubes inhomogeneous hydrogen plasma was derived by solving the electromagnetic wave propagation equation by using the transfer matrix method. The microwave attenuation coefficients of carbon nanotube hydrogen plasma films with different density distributions and different magnetic field intensities are numerically calculated. The results show that the density distribution of hydrogen plasma and the applied magnetic field intensity have important influence on the microwave absorption, and the microwave attenuation absorption coefficient increases when increasing the inhomogeneity of free electron density in hydrogen plasma proportionally. With the increase of magnetic field intensity, the microwave absorption peak of carbon nanotube hydrogen plasma film shifts to high frequency. The energy attenuation of incident electromagnetic wave in carbon nanotube (CNT) inhomogeneous hydrogen plasma film is larger than that of 30d B/cm, which is favorable to microwave absorption, and the numerical results are in agreement with the experimental data obtained. Combined with the previous research results of our group, we can see that if the free electron density of the plasma in carbon nanotubes is properly controlled, the effective frequency of electron collision and the applied magnetic field intensity can be obtained. It is possible to realize the tunable absorption of hydrogen plasma film to microwave in carbon nanotubes. The purpose of this paper is to provide a theoretical reference for the application of carbon nanotube hydrogen plasma in modern military stealth and civil microwave protection.
【学位授予单位】：南华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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