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机载短波天线间隔离度的全波分析 总被引:3,自引:3,他引:0
对飞机等复杂形体及机载短波天线进行全波FDTD数值模拟所需的数学建模方法的介绍,研究了机载短波天线间隔离度的分析计算方法,并以波音707-320B飞机为例计算了机上4付短波天线间隔离度。所用方法及所得结果可作为飞机电磁兼容分析与设计的手段和依据。 相似文献
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机载天线电磁兼容技术分析 总被引:1,自引:0,他引:1
随着机载天线的广泛应用,电磁兼容问题的分析非常重要。针对机载天线的特点,首先对机载天线电磁兼容的核心问题和主要解决途径进行了简要介绍,论述了机载天线隔离度的定义及计算方法,对常用的有限元法、物理光学、几何光学和几何绕射理论等天线电磁兼容技术分析方法进行了比较,最后结合飞机系统的具体情况提出采用混合方法分析机载天线电磁兼容技术问题。 相似文献
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并行UTD算法及在机载天线分析中的应用 总被引:5,自引:2,他引:3
要实现对复杂环境的EMC分析,最大的障碍是计算量过大,耗时太长.本文提出MPI结合UTD的并行算法,实现了大型复杂飞行器机载天线的方向图特性分析.数值结果表明,并行UTD算法可以大大节省计算时间.这一方法为在小型机系统下实现大型EMC分析软件提供了坚实的基础. 相似文献
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机载天线隔离度仿真与分析 总被引:1,自引:0,他引:1
天线隔离度是机载电子系统实现电磁兼容预测的重要参数.根据反应积分原理,提出采用孤立天线远场方向图来替代实际环境中天线的办法,简化分析模型,在保证分析精度的基础上,提高计算效率,从而高效完成电大尺寸环境中天线隔离度的仿真分析.通过在自由空间情况下进行测试,验证了仿真结果的准确性. 相似文献
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柱状机体/星体与天线间的电磁兼容性 总被引:1,自引:0,他引:1
针对常规飞机、卫星等的几何形状,用时域有限差分法(FDTD)分析了圆柱形良导体外形(用以模拟飞机卫星等的机体)对机载/星载天线(文中采用了线天线)辐射特性的影响.通过改变柱形的直径和长度,对天线辐射方向图的变化进行了大量的研究,并得出了一些规律性的结果.该结果对于预测机体和星体与天线的电磁兼容及系统电磁兼容性设计具有参考意义. 相似文献
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By means of exact conformal mapping method we have defined character of dependence of squares amounts of angular part of film
element on angled part dimension. We propose relations, approximating obtained dependence. Calculation results and experimental
researches of large-scale models are represented. 相似文献
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Moshrefzadeh R.S. Radcliffe M.D. Lee T.C. Mohapatra S.K. 《Lightwave Technology, Journal of》1992,10(4):420-425
The temperature dependence of refractive index of polymer films was determined for a number of slab waveguides by a grating coupling method. This dependence was examined as a function of parameters such as molecular weight and glass transition temperature of the polymer. Temperature-induced changes in N TE-N TM , N being the effective index, were studied systematically for different slab waveguide compositions. It is shown that with proper device design and choice of polymeric materials, thermal effects can be reduced 相似文献
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The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde. 相似文献
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解决IP网QoS问题是目前通信领域的研究热点之一.虽然研究已经取得了一定的进展,但人们对于IP 网QoS本身的含义及相关的问题还有着不同的理解.本文将从IP网QoS的定义入手讨论相关的一些问题以及解决IP网QoS问题所做的各种努力. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1968,56(6):1024-1032
Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature. 相似文献
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The approaches to prepare a uniform and unified scientific terminology of chemical carcinogenesis are presented. The main definitions proposed (carcinogen, initiation, promotion, mutagen, multistage carcinogenesis, anti-carcinogen, cocarcinogen, carcinogenic risk, etc.) are based on the current state of comprehending mechanisms of the action of chemical carcinogens. 相似文献
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近红外光谱技术在水果品质无损检测中应用的研究与现状 总被引:6,自引:0,他引:6
简单概述了我国水果产业的发展现状,着重阐述了国内外利用近红外光谱技术进行水果品质无损检测的最新研究进展,分析了当今研究中存在的问题,并对利用近红外光谱技术进行水果检测的前景进行了展望,提出了一些建议。 相似文献