利用传输线延迟特性实现时间测量

首先简要阐述了“细”时间测量的原理,接着详细介绍了传输线的延迟特性及影响此特性的几个要素,分析了利用传输线的延迟特性来实现“细”时间测量的可设计性,然后给出了延迟单元的实现方法及其仿真结果.该方法的特点是:结构简单,工程易实现,同时测量精度较高.最后展望了传输线的应用前景.     

神光Ⅱ装置高功率激光能量测量

在惯性约束聚变实验及X光激光研究中,激光驱动器的激光能量测量是一项十分重要的课题.准确测定打靶激光能量对实验数据分析处理、得出正确的物理规律具有非常重要的意义.神光Ⅱ装置是具有基频(1ω)、二倍频(2ω)及三倍频(3ω)三种波长激光能量输出的国内最大的高功率激光物理实验装置.激光脉宽分纳秒、100 ps、20 ps及皮秒4档可调.在不同脉宽条件下,有不同量级的激光能量输出,当物理实验要求激光脉宽为纳秒量级时,1ω激光能量输出大于4.8 kJ,2ω激光能量输出大于3.0 kJ,3ω激光能量输出大于2.0 kJ.在整个神光Ⅱ装置中共设置了68个激光能量测量网点,包括十项测量内容.在这些测量中,有的信息量很大,有的信息量很小,有的大光斑取样,有的小光束测量.为了适应神光Ⅱ装置激光能量测量的需要,在调研国内外有关资料的基础上,采用了热电堆焊接的新工艺、成对设计的差分结构、双层热屏蔽的隔离外壳等措施,使研制的体吸收激光能量计在灵敏度、均匀性、稳定性等方面都有大幅度提高,经中国计量院标定测试,其性能超过原设计指标要求,达到或超过美国阿波罗激光公司(Apollo Laser Inc.)制造的同类型激光能量计的水平,满足了神光Ⅱ装置多波长高功率激光能量测量的需要.(PG3)     

利用传输线模型的载流子倍增寄存器的频率特性研究

介绍了一种电荷载流子倍增寄存器(CCM)电极问隙的传输线模型,通过求解其波动方程得到了电荷载流子倍增寄存器电极间隙的电势分布及电场分布.模拟分析表明:电荷载流子倍增寄存器电极间隙的电势分布是与电荷载流子倍增寄存器工作频率相关的函数.电势分布沿信号电荷密度流方向衰减且电荷载流子倍增寄存器工作频率越高,电势衰减越快.电荷栽...     

基于FFT的传输线串扰时域响应分析与实验研究

基于传输线分布参数结点导纳方程和快速傅立叶反变换方法,仿真分析了传输线串扰电压响应及传输线参数和端接阻抗对串扰电压峰值的影响.发现在不考虑传输线终端负载电阻的电感影响时,仿真结果中振荡不明显,在考虑电感时仿真结果振荡较明显.基于实验室研究设备,对共地平行传输线间的串扰电压和电流进行了实验研究,并将部分实验结果与理论仿真结果进行了比较.结果显示:在考虑传输线终端负载电感时的仿真波形与幅度和测量结果的波形与幅度基本一致,仿真的脉冲宽度要大于测量脉冲宽度,仿真结果峰值略大于测量峰值.     

惯性聚变能领域的激光二极管抽运固体激光装置

采用激光二极管抽运固体激光(DPSSL)装置作为驱动器是惯性聚变能源(IFE)领域的重要技术途径,可兼顾高峰值功率和高平均功率.介绍了4种单发能量百焦耳、脉宽纳秒级的重复频率同体激光装置,包括系统的概念设计、实验进展,以及放大器构型、能量提取方案、介质热管理等关键单元技术.     

日本聚变项目的最新进展

概述了日本惯性聚变项目的背景和各大项目的最新进展.主要有:1)日本大阪大学激光工程研究所和日本核聚变科学研究所核融合科学研究所(National Institute for Fusion Science,NIFS)联合运作的快点火实证计划项目(Fast Ignition Realization Experiment,FIREX)第一阶段;2)由NIFS运作的大型螺旋装置项目(Large Helical Device,LHD);3)日本原子力开发研究机构那珂核聚变研究所(Naka Fusion Institute,Japan Atomic Energy Agency)的JT-60托卡马克装置.     

测量细胞硬度的计测装置

测量细胞硬度的计测装置日本新技术事业团动态计测小组开发一种利用振动原理，分析细胞结构的细胞振动计测装置。该装置能无损测量细胞内染色体的空间排列，其目的是研究空间排列与细胞功能间的关系。采用的动态法，是一种主要应用于触诊的定量方法，装置结构简单。把这种...     

测量和监视装置的控制

本文从企业管理的角度，结合黄河机电有限公司《质量手册》中测量和监视装置的控制要求及本单位计量管理工作的状况，分别通过测量装置、监视装置的含义和计量管理部门如何做好量值溯源与传递以及特殊测量、监视装置的管理三个方面的阐述，浅谈了对测量和监视装置控制的认识和理解。     

Circuit-Based Analysis of Electromagnetic Field Coupling With Nonuniform Transmission Lines

This paper presents a new algorithm for simulating electromagnetic (EM) field coupling with nonuniform multiconductor transmission lines in a circuit simulation environment. The proposed algorithm is based on the concept of passive model-order reduction, whereby an algorithmically developed passive reduced-order model, coupled with a set of equivalent sources representing the incident filed, are shown to accurately capture the behavior of the transmission line under EM excitation. The reduced-order model is developed independently from the particular shape of the incident field pulse, in the sense that, in constructing the model, one does not need prior knowledge about the waveform of the incident pulse of the EM field. In addition, it is also shown that the model developed can be used to simulate the transmission line in the absence of the EM field. The derived equivalent sources, representing the field coupling, are given directly in the time domain, thereby making simulation under nonlinear circuit terminations an easy task. Although the proposed work is aimed mainly at simulating nonuniform transmission lines, it can be applied to uniform lines as a special case. The proposed algorithm has been validated numerically with several examples.     

Frequency Response of Multiconductor Transmission Lines Illuminated by an Electromagnetic Field

A well-known result [1], [2] for the response of a two-wire transmission line illuminated by a nonuniform electromagnetic field is extended to multiconductor lines. A simple matrix equation for the currents induced in arbitrary termination networks is obtained. Air Development Center.     

平面电磁波对双导线传输线终端瞬态响应的求解

随着传输线方法在电磁兼容和电磁干扰分析方面的广泛应用,人们对传输线方程的求解方法也越来越感兴趣.求解传输线方程的方法通常有时域差分方法和频域差分法.而对于平面电磁波对双导线传输线终端的响应,文章给出了其频域解析解,并且运用这个解析解和Fourier变换技术,可以很容易地给出传输线终端的瞬态响应分析.通过数值仿真实验研究三个角度参数φ、α和Ψ在电磁感应中的作用:当φ和α保持不变(或者Ψ和α保持不变),随着Ψ(或者φ)的增大,终端2的感应电流的响应时间缩短,第一阶段的感应时间延长;当φ和Ψ保持不变,随着α的增大,终端2处第一阶段的感应电流也随之减小.     

Transient Response of Multiconductor Transmission Lines Excited by a Nonuniform Electromagnetic Field

The time-domain transmission-line equations for uniform multiconductor transmission lines in a conductive, homogeneous medium excited by a transient, nonuniform electromagnetic (EM) field, are derived from Maxwell's equations. Depending on how the line voltage is defined, two formulations are possible. One of these formulations is considerably more convenient to apply than the other. The assumptions made in the derivation of the transmission-line equations and the boundary conditions at the terminations are discussed. For numerical calculations, the transmission -line equations are represented by finite-difference techniques, and numerical examples are included.     

Measurement of Electromagnetic Field Immunity

A short survey is given of various methods proposed for the measurement of equipment immunity to extraneous electromagnetic fields. Their relative merits are discussed and progress in international standardization within the IEC is reported.     

Harmonic Composition of Low-Frequency Electromagnetic Emissions Associated with High-Voltage Transmission

Electric-field-strength measures of the spectrum between 10 and 200 kHz were obtained under dry conditions near a 500-kV transmission line. Comparison of the magnitudes of electric field strength between the odd and even harmonics of 60 Hz revealed a marked asymmetry. The ratio of odd to even harmonic field strength ranged from 19 to 3.3. A primary source of these emissions may be produced by components within the power systems with nonlinearities that are best described by odd functions.     

场敏感型自适应电磁防护材料的测试装置与方法研究

场敏感型环境自适应电磁防护材料属于新材料,当外部电磁场超过某临界场强的时候,该材料可以在微纳秒时间内即刻发生绝缘/ 导电相变现象,即平时为绝缘体的材料迅速变为高导电的类金属材料,由于该材料发生相变的临界场强阈值较高,传统的材料静态测试方法以及低压动态测试都无法满足测试需求。根据该材料的工作机理,设计了一种可以产生高场强的动态测试系统,通过仿真和电磁场理论分析了该测试夹具的可行性,确定了其具体参数,进而研制成功了一种用于该材料的动态测试夹具,确定了其相应的测试方法,通过试验发现,该夹具可以对突变后类金属材料的等效电阻为1 kW以下、1 ms 以下的响应时间、1 MV/ m 以下的临界场强进行电阻率、响应时间和临界场强阈值的测试。     

Analysis of Miniature Electric Field Probes with Resistive Transmission Lines

The miniature dipole probe is a useful tool for measuring the electric field at high radio and microwave frequencies. A common design for the probe consists of an electrically short dipole antenna with a diode across its terminals; a resistive, parallel-wire transmission line transmits the detected signal from the diode to the monitoring instrumentation. The high resistance per unit length of the transmission line reduces the direct reception of the incident field by the line and also reduces the scattering of the incident field by the line. In addition, the resistive transmission line serves as a low-pass filter in the detection process. In this paper, the effect of the resistive transmission line on the operation of the miniature field probe is analyzed. Specifically, the reception of the incident signal by the transmission line is compared with that of the dipole. The scattering of the incident signal by the transmission line is studied by means of the scattering cross section, and the limitation imposed on the measurement of amplitude-modulated signals by the low-pass filtering by the resistive line is examined. The results of the theoretical analyses are presented as simple formulas which are useful in the design and optimization of the probe. The theoretical results are shown to be in good agreement with measurements.     

“电磁场与电磁波”教学方法研究与实践

“电磁场与电磁波”是我校应用型本科的一门基础课。为了提高学生的学习兴趣、动手能力和理论知识的工程应用能力,本文针对该课程的特点、学生学习以及教师教学过程中存在的普遍问题,采用举例法对理论课、实验课、网络以及实践教学四个环节的教学方法进行了探讨。实践证明,这些方法取得了良好的教学效果。     

数据融合技术在输电线网故障诊断中的应用

数据融合作为一门信息综合处理技术起初应用于军事领域，被引入到技术科学领域只有近十的年的历史。本文开始简述了数据融合的定义，接着阐明了将数据融合应用于输电线网故障诊断可行性的理论依据，然后论述了多种数据融合方法，如人工神经网络、专家系统、模糊理论、小波分析等在输电线网故障中的应用。