电机内电磁场分布有限元分析

阐述某单相永磁步进电机内的电磁场的有限元分析过程，给出了利用ANSYS软件进行有限元分析得出的结果，并根据分析结果对单相永磁步进电机进行了优化设计。     

典型电力通信共享铁塔电磁场分布特征研究

随着我国电力行业与通信行业的不断发展进步,电力通信技术广泛应用于我国的各行各业.近几年,共享相关的词语和行业不断被市场提出,共享铁塔由于其自身的优点被广泛关注.电力通信共享铁塔是电力与通信信息铁塔的结合构造,由于电力和信息信号在运行中会产生一定的电磁场,因此研究典型电力通信共享铁塔电磁场分布特征将对我国的电力通信事...     

基于粒子系统的电磁场强分布计算方法

针对电磁对抗领域中电磁态势显示的需求及传统电磁传播模型计算速度慢的现状,提出了一种基于粒子系统的电磁场强计算及显示方法。将基于电磁波传播模型的辐射源空间电磁场强计算简化为基于粒子系统的图形计算及显示方法,针对辐射源工作参数及天线方向图数据生成OSG粒子模型,利用OSG引擎的高速计算及渲染能力,直接将计算结果渲染至二维/三维态势图中,实现了在复杂电磁环境下电磁态势的实时显示。     

电磁场的内禀角动量

电磁场流体模型理论的基本点是把电磁场运动区分为轨道运动与内禀运动两部分。本文试图从内禀运动部分引出内禀角动量的概念。为此,建立了(虚数)算符;导出了电磁场的自旋角动量与内禀角动量的关系。     

高阶各向异性阻抗界条件的导出

在求解各向异性介质涂敷物体的电磁散射中,采用高阶各向异性阻抗边界条件可以简化求解过程,提高近似解的精度。文中采用谱域法法导出各向异性介质涂敷平面的二阶张量阻抗边界条件,并通过例子证明其精确性。     

非线性介质内电磁场的量子化

本文对电位移矢量D以及磁感应强度B引入失势C_μ,利用正则量子化方法,将非线性介质中的电磁场进行量子化,从而得出自洽理论。     

有耗各向异性材料的判别准则

从Maxwell方程出发，导出了平面波入射到半无界均匀各向异性媒质时电磁场的相互关系，根据有耗媒质应满足波传播条件和玻印廷矢量散度的实部应小于零，推得了无源有耗各向异性材料参数应满足的条件，论述了该有耗判别准则的充要性，为任意吸波材料参数的反演研究打下了理论基础。     

脑组织双重免疫荧光标记方法介绍

应用光学技术对荧光标记的组织切片样品进行成像观察是生物学研究的常规手段。本文主要介绍如何制备用于荧光显微镜和激光共聚焦显微镜成像的脑组织石蜡切片免疫荧光双重标记技术。     

UARAC的电磁特性分析

为了解决单轴各向异性吸波涂层(UARAC)的分析和设计中所遇到的反射系数计算问题,从电磁场理论出发,导出了电磁波以任意角入射时UARAC的反射系数公式。同时,给出了计算曲线的例子,通过实例计算分析了UARAC的斜入射特性和电磁波的入射角、极化状态等对UARAC的隐身效果的影响。得到负单轴各向异性吸波涂层(MUARAC)的吸波性能优于正单轴各向异性吸波涂层(PUARAC)的吸波性能及MUARAC的吸波性能主要取决于单轴各向异性吸波材料的横向参数等结论。为UARAC的计算机辅助分析和设计提供了基础。     

电磁反常涡旋光束在各向异性大气湍流中的偏振特性

本文研究了部分相干电磁反常涡旋光束(PCEAVB)通过各向异性non-Kolmogorov大气湍流后的偏振度和偏振态的变化.研究结果表明,PCEAVB的偏振度分布为同心的圆环,而随着光束阶数n和拓扑荷数m的增大,同心圆环数逐渐增加,分布越密集.光束阶数n越高、拓扑荷数m越低,高偏振度分布区域越趋于中间区域;反之,则趋于...     

Modeling the field distribution in deep brain stimulation: the influence of anisotropy of brain tissue

The neurosurgical method of deep brain stimulation (DBS) is used to treat symptoms of movement disorders like Parkinson's disease by implanting stimulation electrodes in deep brain areas. The aim of this study was to examine the field distribution in DBS and the role of heterogeneous and anisotropic material properties in the brain areas where stimulation is applied. Finite element models of the human brain were developed comprising tissue heterogeneity and anisotropy. The tissue data were derived from averaged magnetic resonance imaging and diffusion tensor imaging datasets. Unilateral stimulation of the subthalamic nucleus (STN) was computed using an accurate model of an electrode used in clinical treatment of DBS extended with an encapsulation layer around the electrode body. Computations of anisotropic and isotropic brain models, which consider resistive tissue properties for unipolar and bipolar electrode configurations, were carried out. Electrode position was varied within an area around the stimulation center. Results have shown a deviation of 2% between anisotropic and isotropic field distributions in the vicinity of the STN. The sensitivity of this deviation referring to the electrode position remained small, but increased when the electrode position approached areas of high anisotropy.     

空心高斯涡旋光束在各向异性non-Kolmogorov大气湍流的光强分布

为了分析大气湍流对空心涡旋光束传输光强的影响,基于广义惠更斯-菲涅尔原理和Rytov相位结构函数近似,利用各向异性大气non-Kolmogorov湍流谱模型,推导出空心高斯涡旋(HGV)光束在各向异性大气湍流中的传输光强解析式,数值模拟分析了传输距离、湍流参数和光束参数对光强分布的影响.研究结果表明:随着传输距离增大,...     

Electromagnetic field of a horizontal electric dipole buried in a medium covering one-dimensionally anisotropic medium

The electromagnetic fields of a horizontal electric dipole buried in a medium covering one-dimensionally anisotropic medium are studied. There are three media, one-dimensionally anisotropic medium covered with a dielectric under the air. The electromagnetic field components are complex because of the multiple reflections from the up and down boundaries. The electromagnetic field components between air and one-dimensionally anisotropic medium are given, the trapped surface waves and lateral waves along the dielectric-anisotropic medium boundary are computed. The results have some practical applications in the communication in sea or lake above one-dimensionally anisotropic earth or sediments.     

Resistance value and field distribution of rectangular anisotropic resistive region

High accurate resistance values and field distributions for a rectangular anisotropic resistive region are presented by using an affine transformation and a Schwarz-Christoffel transformation. Interesting comparison between the field distribution in a Hall generator and the present result is also presented.     

矩形波导中电磁场分布特征研究

波导内电磁场结构复杂,为了解矩形波导中电磁场分布特征,由矩形波导中的TM波和TE波场方程确定波导空间任意时刻、任意位置各分量量值,进而确定空间任意位置电场和磁场矢量的指向,模拟出波导截面和纵剖面的TM11波和TE11波的电磁场分布图。模拟结果得出的结论符合实际,正确地反映了矩形波导中电磁波传播特征,对了解波导中电磁场特性具有重要意义。     

The electromagnetic field in rotating coordinates

It is shown that electromagnetic field equations in rotating coordinates, obtained by several authors, are faulty due to their basis in incorrect expressions for the divergence and curl operators and the three-dimensional spatial vectors. A four-dimensional (4-vector) tensor formulation is used to show that Maxwell's equations are shown to be valid in rotating coordinates