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本文利用 A.L.Aden和 M.Kerker微粒子 Mie散射理论计算了处于高分子介质中的Al2 O3微粒子的消光截面、散射截面以及散射强度分布函数 ,并和它们在空气介质中的结果进行了比较。  相似文献
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The smoke is often generated in the battlefield by the smoke ammunition to protect the personnel and equipment against the enemy's optoelectronic systems. The effective extinction cross section is an important parameter of the infrared smoke ammunition. In this paper, the relationships between the effective extinction cross section of a cloud of spherical smoke and the mass of the smoke agent, the radius of the screening smoke and the mass extinction coefficient are discussed. The expressions of the maximal effective extinction cross section is derived. This research will help us to achieve optimal design of the smoke ammunition and to appropriately evaluate the effectiveness of the smoke. Examples are given for two kinds of obscurants.  相似文献
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We employ the numerically exact superposition T-matrix method to perform extensive computations of scattering and absorption properties of soot aggregates with varying state of compactness and size. The fractal dimension, Df, is used to quantify the geometrical mass dispersion of the clusters. The optical properties of soot aggregates for a given fractal dimension are complex functions of the refractive index of the material m, the number of monomers NS, and the monomer radius a. It is shown that for smaller values of a, the absorption cross section tends to be relatively constant when Df<2 but increases rapidly when Df>2. However, a systematic reduction in light absorption with Df is observed for clusters with sufficiently large NS, m, and a. The scattering cross section and single-scattering albedo increase monotonically as fractals evolve from chain-like to more densely packed morphologies, which is a strong manifestation of the increasing importance of scattering interaction among spherules. Overall, the results for soot fractals differ profoundly from those calculated for the respective volume-equivalent soot spheres as well as for the respective external mixtures of soot monomers under the assumption that there are no electromagnetic interactions between the monomers. The climate-research implications of our results are discussed.  相似文献
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纳米碳纤维是一种新型吸波材料。为探讨烟幕粒子的红外消光特性,利用矩量法建立了纳米碳纤维感应电流和散射场的计算模型,在此基础上得出了纳米碳纤维吸收、散射和消光截面的计算表达式。通过Matlab编程计算分析了纳米碳纤维红外消光截面与电导率的关系。结果表明,纳米碳纤维红外消光特性与电导率密切相关,随着电导率的增加,消光截面迅速增加,当波长大于纤维本身长度时,消光截面随电导率的变化出现峰值,峰值电导率与波长有关。  相似文献
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周明善*  徐铭 《物理学报》2013,62(9):97201-097201
为探讨膨胀石墨作为3 mm波干扰材料的消光、散射特性及其影响因素, 基于有限长度、有限电导率圆柱状导体的电磁散射, 利用矩量法建立了膨胀石墨的消光、散射、吸收及后向散射截面(雷达散射截面RCS)的计算式. 运用Mathematica编程计算并分析了膨胀石墨长度、半径、电导率、磁导率等因素与膨胀石墨消光、散射、吸收截面及RCS的关系. 结果表明: 当膨胀石墨的长度为1.5 mm、半径为0.05 mm时, 具有较好的消光、散射效果; 适当增大膨胀石墨的电导率、磁导率, 有利于提高其消光、散射能力. 本研究为探索增强膨胀石墨干扰3 mm波效果的技术途径提供了有价值的参考. 关键词: 膨胀石墨 石墨层间化合物 消光截面 矩量法  相似文献
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本文采用二维有限元方法,研究了由非对称半径及间距组成的银纳米线三聚体的等离子体共振以及异常的电场分布现象. 模拟结果显示,非对称银纳米线三聚体中存在亮模和暗模. 当亮模分布于两根半径较小的纳米线之间时,会导致在较大半径的两根纳米线间出现较高的场增强分布,说明级联效应被抑制. 相反,当两根半径较小的纳米线之间存在暗模时,较大的场增强存在于两根较小半径的纳米线间,此时所产生的级联效应得以实现.  相似文献
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