混合动力汽车电磁场辐射骚扰特性研究

针对某混合动力汽车低频电磁场辐射发射电平达不到国家标准的问题,研究混合动力汽车的低频电磁场辐射骚扰特性,诊断分析其主要骚扰源及电磁骚扰产生机理,采取对应的电磁兼容技术措施进行整改,并通过试验验证其有效性,为同行提供参考。     

谁该告诉消费者事实

每年一到3.15,就出现一些稀奇古怪的"车辆安全和质量问题",有的问题恐怕在车圈里待了十几年的老人也未必听说过。而且自从有了方舟子老师的科学打假之后,这些车辆的"安全和质量问题"也越来越奔着高科技去了。比如近日来的"车内电磁辐射"问题,让我们这些汽车专业出身的人是一头雾水,求教了诸多通讯系统和     

基于ANSYS大型同步电机电磁场分析与参数计算

本文研究了基于ANSYS的大型凸极同步电机电磁场分析与参数计算的问题。根据电机一对极的求解区域,建立了电磁场分析的物理模型和数学模型,采用有限元法求解了同步电机空载时的气隙磁密分布和电枢反应时的磁场分布,计算了空载特性、额定工况下的饱和同步电抗和不饱和同步电抗,为电机的工程研制提供有价值的参考。     

GPR电磁波在层状路面中传播的正演模拟

系统阐述了电磁场有限单元法的基本原理,然后采用四节点等参单元分别对三层路面系统进行了静态场和时变场的有限元分析,初步建立了路用探地雷达GPR电磁波在三层路面中传播的正演模型,同实测波形相比,模拟效果较好,并用Fortran90语言编制了相应的三维、二维有限元程序,具有较好的可读性和可移植性.     

Fracture Mechanics for a Mode Ⅲ Crack in a Piezoelectromagnetic Material

Analytical solutions for a Griffith crack inside an infinite piezoelectromagnetic medium under combined mechanical-electrical-magnetic loadings are formulated using integral transform method. The singular stress, elec tric and magnetic fields in the piezoelectromagnetic material are obtained by the theory of linear piezoelectromagneticity. Fourier transforms are used to reduce the mixed boundary value problems of the crack, which is as sumed to be permeable, to dual integral equations. The solution of the dual integral equations is then expressed analytically. Expressions for strains, stresses, electric fields, electric displacements, magnetic fields and magnetic inductions in the vicinity of the crack tip are derived. Field intensity factors and energy release rate for piezoelectromagnetic material are obtained. The stresses, electric displacements and magnetic inductions at the crack tip show the traditional square root singularities; and the electric field intensity factor （EFIF） and the magnetic field intensity factor （MFIF） are always zero.     

Propagating Characteristics of Confocal Elliptical Waveguide Filled with Multilayered Dielectrics

Using the method of separation of variables in the elliptical coordinate system, a recursive formula for the electromagnetic fields in a confocal elliptical waveguide filled with multi-layered homogeneous isotropic media is derived; then the eigenequation for it is given. When an elliptical waveguide becomes a circular waveguide, the electromagnetic fields and the eigenequation of the circular waveguide can be obtained from the eigenequation of the elliptical waveguide using the asymptotic formulae of Mathieu and modified Mathieu functions for a large radial coordinate in the elliptical coordinate system, and the eigenequation of a circular waveguide filled with multilayered dielectrics can be treated as a special case of an elliptical waveguide.In addition, some numerical examples are presented to analyze the propagating characteristics influenced by the perrnittivity, permeability of dielectrics filled in the elliptical waveguide, etc. The results show that changing the permittivity or permeability of the dielectrics filled in the waveguide and the major semiaxis value of the i-th layer can change the propagating characteristics of an elliptical waveguide.     

基于电磁场分析的船用天线布置与安装

针对船舶罗经甲板需要安装布置的天线越来越多的实际情况,利用电磁场基本理论对船用天线产生的电磁场和电磁干扰情况进行分析,在梳理船舶建造规范关于船用天线布置与安装基本要求的基础上,根据船舶建造的实际情况,设计了某散货船的天线布置俯视图、B向图和侧视图,使得天线之间的电磁干扰尽量降低,保证船舶电子设备和系统的正常运行,进而确保船舶的安全航行。     

关于区间贯通地线屡次被盗的思考

贯通地线作为安全地线、屏蔽地线和防雷地线的综合地线，其作用非同一般。它对于保证信号设备安全、避免雷击、防止外界电磁场对信号的干扰都有非常重要的作用。特别是电气化区段，其接地的好坏还影响着维修人员的人身安全。[第一段]     

PLC控制系统抗干扰分析

对铁路信号中的PLC控制系统的可靠性进行了分析和研究，并从电源、电缆、硬件及软件等几个方面提出了改善措施。     

测量探头在电磁场计算中的影响

评估了测量探头对一个电磁源的远场和近场的影响。测量时，测量探头将对电磁场产生干扰，因此，测量的场是受到干扰的场，而不是自由空间场。这种干扰不能通过校准来完全消除，尤其是对近场。对于一个十分敏感的测量探头，其对近场的干扰远大于远场。研究说明，当干扰必须小于一个预定值时(如5％)，可选择一个灵敏度最大而适合的测量探头。这可以利用一个数值电磁计算程序来完成。