30MHz～1GHz辐射骚扰场强测试10米法和3米法探讨

讨论了30MHz-1GHz辐射骚扰场强测试中，10米法和3米法测试结果的差异，并简单地分析了产生差异的原因，例如，远近场问题，测试角度范围的不同，暗室本身的归一化场地衰减（NSA）都会对测试结果产生差异。     

Accurate CAD model of stopping distance to compute conductor loss of CPW

The theoretical and experimentally extracted closed-form models of stopping distance are presented that provides the CAD oriented simple model to compute conductor loss of CPW with average deviation within 5.4% against the experimental results from three independent sources. Whereas the models of Holloway and Kuester has 14.6% error and model of Ponchak et al. has 17.1% error, against same sets of experimental results. The accuarcy of the models is examined in frequency range 1–120 GHz.     

Acoustical and optical branches of wave propagation in random particulate composites

The work is dedicated to the analysis of acoustical and optical branches of longitudinal elastic wave propagation in the medium with a random set of spherical inclusions. The effective field method and quasicrystalline approximation are used for the construction of the dispersion equation for the wave number of the mean (coherent) wave field propagating in the composite. This dispersion equation serves for all frequencies of the incident field, properties and volume concentrations of inclusions. Different branches of the solutions of this equation are obtained and analyzed. Each of these branches may be interpreted as a specific mode of wave propagation, and its input in the mean (coherent) wave field is essential only in a certain frequency region. The predictions of the method are compared with some experimental data existing in the literature.     

移动通信(3G)的发展与射频同轴电缆

本文阐述了移动通信,特别是第三代移动通信的发展,分析了射频同轴电缆的结构、特点及生产制遣,探讨了适应第三代移动通信网络建设性能要求的射频同轴电缆的工艺改进问题。     

在旋流扶正器作用下环空流场旋流衰减规律研究

在油气井固井注水泥顶替技术中，传统的一维轴向流顶替方式不能有效替净环空被顶替液；而使用旋流扶正器不仅提高套管居中度，还能使环空流体改变流速剖面而做螺旋运动，这使轴向驱替的同时增加一周向剪切驱动力，从而有利于将环空窄间隙滞留泥浆和井壁附着虚滤饼驱替干净,提高固井质量。文章对旋流扶正器本身结构、流体性能、施工排量与旋流发展之间的关系进行了较为全面的研究，研究得出的旋流周向速度的经验公式，计算精度较高，对计算边壁剪切应力，设计旋流扶正器的间距具有重要的意义。     

沙尘衰减对微波通信的影响

通过分析沙尘尺寸分布,在计算干沙和纯水的复介电常数的基础上,利用粒子散射理论给出了微波传输中的沙尘衰减的计算模型,该模型分析了爆炸沙尘、车扬沙尘和自然沙尘三种不同的沙尘的衰减。通过数值计算的结果,仿真了不同含水量下沙尘衰减率随微波频率的变化,最后给出了相关结论。     

新型高强度弹簧钢40Si2CrNi2MoV的研制

研制的高强韧性新型弹簧钢 4 0Si2CrNi2MoV(4 0T)的σb≥ 195 0MPa ,σ0 .2 ≥ 175 0MPa ,δ5≥ 9% ,ψ≥30 % ,AK～ 30J。该钢的抗弹减性均优于弹簧钢 6 0Si2CrVA。该钢适于制造高应力、大截面弹簧 ,用于制造铁路货车转向架弹簧时 ,设计应力 116 0MPa ,在弹簧疲劳试验中 ,平均应力为 6 4 7MPa ,应力幅值为平均应力的 0 4倍 ,最大应力 90 6MPa ,最小应力 388MPa ,循环周次达 2× 10 6次未发生断裂。     

电抗器匝间过电压试验方法——脉冲电压法的分析

本文对用于电抗器特别是干式空心电抗器匝间过电压试验的脉冲电压法进行了介绍和分析，阐述了其基本原理、操作顺序和故障观测、辨别的方法。     

Spherical surface parameterization for perspective shape from shading

We propose a new mathematical formulation for perspective shape from shading (PSFS) problems. Our approach is based on representing the unknown surface as a spherical surface, expressed by Euclidean distance to the optical centre, as opposed to the traditional representation by distance from the image plane. We show that our parameterization is better suited for perspective camera models and results in simpler models and equations for classical PSFS problems with a light source in the optical centre. The unknown distance field satisfies a simple isotropic Eikonal equation on the unit sphere in the case of a Lambertian surface reflection model. This is in contrast to previous methods with depth field parameterization, which result in anisotropic equations. Adding light attenuation to the model, we show that the distance field satisfies an Eikonal type of equation with a zero order term. We show how both Eikonal equations can be approximated by very efficient Fast Marching methods. A number of numerical tests and examples are provided to demonstrate our approach, and to compare with previous work. Our results indicate competitive accuracy and computational time that are several orders of magnitude faster than state-of-the-art iterative algorithms. A preliminary investigation indicates that our method could be used in more general PSFS problems.     

超声多普勒胎心仪超声源检定方法探讨

超声多普勒胎心仪超声源是临床诊断的重要手段之一。本文主要介绍了超声多普勒胎心仪超声源检定项目、技术要求及检定方法并介绍了所需要的测量装置，对测量过程进行了阐述。给出了计算公式和推算过程及测量精度。