地铁车地无线通信系统电磁兼容研究

地铁在城市交通出行中扮演重要角色,但近年来电磁干扰影响地铁安全营运事故时有发生。为分析机动车和电气化铁路对车地无线通信系统的电磁干扰,从电磁兼容三要素出发,结合实验测试论证了某地地铁车地系统在开放空间及近距离条件下对机动车和电气化铁路具有较好的电磁兼容性,并针对测试过程中所出现的电磁兼容隐患提出了建议。     

Costas序列在雷达信号设计中的应用研究

阐述了Costas序列的代数结构及其特点,分析了常用雷达信号,如线性调频脉冲信号、非线性调频脉冲信号等的模糊函数,文中指出当雷达信号使用Costas序列的构成方法形成跳频扩频的信号时,将获得理想的模糊函数性能,即同时获得极好的距离分辨率和速度分辨率。文中建立了多目标散射、多径衰落和加性高斯白噪声信道的数学模型,并介绍了多目标散射、多径衰落和加性高斯白噪声信道的雷达信号设计方法,最后给出了计算机仿真结果。     

T矩阵的编程实现

T矩阵方法被广泛地应用于粒子的光散射计算中。在计算T矩阵的程序中,绝大部分都是通过FORTRAN语言实现的。本文通过目前最通用的计算机语言C 来实现T矩阵,同时提出了实现过程中应注意的问题。     

“电磁兼容技术”课程案例导入式教学实践

＂电磁兼容技术＂是理论性和工程实践性均较强的一门课程。针对传统教学模式存在的问题,笔者结合自己的科研经验开展了案例导入式教学法的尝试,依据教学进度,精心选择案例,让学生参与进来,从而实现了理论和实践相结合,取得了良好的教学效果。     

Influence of doping on the dynamical properties of III–V–N by Raman scattering, infrared absorption and model calculations

In the framework of a rigid-ion model and using realistic Greens function theory, we have studied systematically the influence of doping on the lattice dynamics of III–V-nitrides. Our theoretical analysis is based on a sound physical appeal for the perturbation caused by different dopants in compound semiconductors. After analyzing the dynamical behavior for two sets of impurities with closest masses occupying Ga- and As-sites in GaAs, we have proposed simple empirical relationships providing corrections to the impurity–host interactions for isoelectronic defects and for dopants carrying static charges. Despite the simplicity of perturbation models, our Greens function theory provided results in good agreement with the recent Fourier-transform infrared (FTIR) absorption data for the magnitude and splitting of N-isotopic shifts of localized vibrational modes in GaAs. With high-resolution FTIR spectroscopy, we strongly believe that the ¹⁴N_As-related broad local mode (471 cm⁻¹) in GaAs can be resolved into fine structures due to Ga-host isotopes. Theoretical results for the in-band modes of As_N in cubic gallium nitride are compared and discussed with the existing Raman data on molecular beam epitaxy (MBE) grown GaN layers on GaAs substrates, as well as on GaN samples intentionally doped with As.     

On Chiroptical Spectroscopy of Turbid Media with Optically Soft, Large Spherical Particles

The influence of the size of particles on the circular dichroism and optical rotatory dispersion spectra of turbid layers with globules of chiral substances is studied. Simple equations for large chiral particles with the refractive index close to the refractive index of the surrounding medium are obtained and analyzed. Formulae derived can be used for the solution of the inverse problem, namely for obtaining intrinsic spectra of substances inside small particles from measurements of spectra for turbid layers.     

（NixZn0.825—xCu0.170Co0.005）Fe1.90O3.85铁氧体的电磁性能

采用配方式（ＮｉｘＺｎ０．８２５－ｘＣｕ０．１７０Ｃｏ０．００５）Ｆｅ１．９０Ｏ３．８５（简称ＮｉＣｕＺｎ铁氧体）在较宽的组成范围内（ｘ＝０．２９５～０．７５０）研究了ＮｉＣｕＺｎ铁氧体的电磁性能,发现ＮｉＣｕＺｎ铁氧体的μ,Ｑ以及温度特性随Ｎｉ含量ｘ的变化与ＮｉＺｎ铁氧体有很大不同,并对产生这种现象的原因进行了初步探讨。     

颗粒浓度及粒度的光散射在线测量

介绍一种在线监测颗粒浓度及粒度变化的光散射方法。着重提出消除观察窗玻璃污染物对测量结果影响的办法。给出了部分现场实测结果。     

聚焦参量对斯托克斯光远场发散角的影响

测量了准分子激光泵浦氢气产生一阶斯托克斯光的远场发散角。结果表明光束质量基本不随氢气压力变化，主要由泵浦光泵浦聚焦参量确定。     

应用激光侧向散射测量粒径分布的理论研究

提出一种新型的颗粒测量方法，基于Ｍｉｅ散射理论，从另一独特的视角接收大角度的侧向散射光，并建立新的理论模型，可使测量下限扩展，技术要求有所改善。结合目前已经成熟的半导体激光和ＣＣＤ技术，运用此原理可使颗粒测量仪器向更轻便、灵敏发展