基于电容放电单元的爆炸丝起爆特性数值分析

对于含多路爆炸丝(强非线性元件)的电容放电单元(CDU),其起爆特性研究中最重要的是掌握爆炸丝工作时的物理特性。本文利用电阻率-比作用量关系描述爆炸丝工作时的电学特性,采用PSPICE对含爆炸丝的CDU回路进行仿真建模,并建立相应的实验平台测量了爆炸丝工作时的电流电压特性。结果表明,仿真结果与实验测量基本吻合：多个爆炸丝串联时,爆炸丝材料特性的差异会影响起爆同步性,而尺寸参数的差异不会影响起爆同步性;多个爆炸丝并联时,爆炸丝材料和尺寸参数的差异都会显著影响起爆同步性及可靠性,容易引起起爆失败。该仿真可用于多路起爆同步性和起爆裕度的定量评估。     

碳纤维复合材料电导率-温度特性测量及其在预测雷击热效应中的应用

飞机的碳纤维复合材料（carbon fiber reinforced polymer,CFRP）蒙皮在遭受雷击时将经受急剧的温升效应,对材料电导率造成重要影响,而这一影响又反作用于焦耳热产生过程.文章通过直接加热和电加热两类实验分别测量了ZT7H/5229D碳纤维/树脂层合板在升降温过程中的电导率温度特性;开展了脉冲大电流试验,测量了模拟雷击情况下材料表面的瞬时温度.将实测的电导率温度参数应用到仿真模型中,仿真分析了脉冲注入实验的瞬时温度,结果表明:两类实验的电导率温度特性有着良好的一致性,CFRP在升降温过程中的回滞环现象、热解及基体热固性变化,会影响加温前后及升降温过程中的电导率;基于实验测量规律的仿真模型能够更准确预测雷电流注入时CFRP的温度场.     

基于积分球的高功率激光多参数测量技术

针对传统测量技术对入射光入射方向敏感的缺点,提出了一种基于积分球的高功率激光多参数测量的分光技术。采用蒙特卡罗法对衰减率、出射光时间波形特性、入射光时间波形恢复这三个方面进行了数值分析和仿真,验证了积分球作为激光测量系统中的分光元件的可行性。利用积分球对纳秒激光的能量和时间波形进行测量,实验结果与理论分析相符。实验与仿真均表明在激光参数测量中采用该分光技术,通过测量出射光各项参数可以恢复入射光的光谱参数、能量参数、时间参数,克服传统技术中入射光的入射方向对于出射光的各项参数有较大影响的问题。该技术方案占用空间小、易于集成,可用于多路高功率激光参数测量系统的模块化设计。     

纳秒半导体激光器的时间抖动和触发同步特性

纳秒半导体激光器（LD）的时间抖动和多个LD并联触发的时间同步性是各类超快光电过程及应用中的重要参数。研究了纳秒脉冲LD（包括LD触发电路）的时间抖动特性以及2个LD的触发同步性。结果表明:纳秒LD（包括LD触发电路）的时间抖动与其驱动电路的驱动电压有关,均在亚纳秒量级范围。单只纳秒LD的时间抖动为72 ps,当1个LD驱动电路同时触发2个并联的纳秒LD时,每个纳秒LD的时间抖动增至约200 ps,2个并联纳秒LD的触发时间同步性近300 ps。     

激光波长对含能材料起爆阈值的影响

为了解激光波长对含能材料起爆阈值的影响,降低含能材料的激光起爆能量,提高激光激励源的小型化程度,采用飞行时间质谱技术和Bruccton升降法,测试了波长1 064 nm和532 nm两种激光对泰安(PETN)的解离谱图和起爆阈值,分析了波长对起爆机理的影响。结果表明:含能材料激光起爆对波长具有选择性,每种含能材料均具有一些有利于起爆的特征吸收波长;不同波长(1 064 nm和532 nm)激发时PETN存在不同的解离机理。相对于532 nm激光,接近特征吸收的1 064 nm激光能够加速PETN的解离,并使其50%发火能量降低14%。因此,采用含能材料特征吸收波长激光作为起爆激励源,能有效的减少含能材料的起爆阈值。     

飞秒激光光丝电学特性实验及模型分析

飞秒激光在高压放电、电场测量等领域中有广阔的应用前景，准确测量飞秒激光的相关电学参数是各领域中飞秒激光应用的前提。基于激光电学特性实验得到了光丝通道在恒定电场下的电流特征，通过电路仿真得出了实验电路的等效元件参数，并通过仿真结果与实验条件联立的方法逆推得出以下结论：对于飞秒激光经过辅助聚焦后形成的光丝，其在实验电路中的等效电阻随光丝传播距离的增加呈现先减小后增大的变化趋势。2.7 mJ飞秒激光光丝在通过5 m焦距透镜后，贯穿2.5 cm放电间隙。在这个过程中，当光丝传播距离为473.6～501.6 cm时，等效电阻为457.5～9122.5 kΩ。所提分析方法能够表征具体激光能量和聚焦距离下的飞秒激光光丝的电学特性，研究结果为飞秒激光在高电压领域中的应用提供了参数支持。     

粒子场全息中的定标方法分析及改进

在粒子场的定量分析中.通常采用外加标准丝作为粒子尺寸测量的定标尺度.为了解一定景深范围内存在的标准丝再现像实验测量结果的影响,从理论和实验上详细分析了标准丝再现像在不同位置处的强度分布及变化,指出了常规定标方法对粒子场图像数据所带来的影响,同时提出了一种新的定标方法--非实时定标方法.实验结果表明,非实时定标方法在保持空间定化精度的基础上,测量得到的标准粒子尺寸的不确定在4%左右.该方法有效地解决了标准丝再现像对粒子尺度测量精度影响问题,可以用于粒子场实际测量工作中.     

一种用于双各向异性材料参数反演的新模型

针对双各向异性材料参数的反演,在多频点测量、多厚度测量、多入射角测量模型的基础上,本文首次提出了一种用于双各向异性材料参数反演的新模型,该模型是由同材料前后两层相对旋转一定角度的双层组成。利用一阶状态矢量法,推导得到了该模型反射传输的计算公式,并分析了双层同材料测量模型的传输特性。与单层平板模型传输特性进行比较表明:有的传输参数在单层时对媒质参数敏感,而有的在双层时对媒质参数敏感。本文的工作为双各向异性吸波材料参数的反演打下了基础。     

微条气体室探测器

本文从多丝正比室（MWPC）特点出发,详细介绍了MSGC的工作原理、结构设计原理、结构参数（包括衬底材料、微条材料、工作气体）的选择依据以及应用前景,并报道了MSGC的最新研究进展。     

耳蜗式多路耦合器的小型化设计

耳蜗式多路耦合器在现代通信系统中有着广泛的应用前景。为了进一步减小耳蜗式多路耦合器的尺寸,采用集总参数与分布参数相结合的半集总参数元件,针对电路中的低阻抗线进行了有效的小型化设计。设计了一款工作于200 MHz~1 000 MHz的恒相对带宽为18%的10通道耳蜗式多路耦合器。仿真和测试结果表明,这种小型化方法使耳蜗式多路耦合器的尺寸缩减为137 mm×116 mm。     

用PTD分析双弯曲反射面天线形变和穿孔的辐射特性

该文根据模型反射面天线的爆炸实验测试结果建立了反射面天线形变的数学模型,应用物理光学(P0)法和物理绕射(PTD)理论计钟:了一种赋形反射面天线形变后的辐射特性,同时还计算了反射面天线表面被爆炸破片穿孔后的辐射特性,结果表明,由于反射面的局部形变,直接导致辐射方向图的恶化,并且随着形变部分面积的增大,水平面的副瓣抬高很大,穿孔也会使水平面的副瓣抬高。     

声表面波器件二阶效应PSPICE仿真

提出了声表面波器件二阶效应的等效电路模型,它应用P矩阵法从理论上推导了声表面波器件二阶效应表达式,得到表征二阶效应的电特性参数,应用电网络理论综合出具有相同电特性的等效电路模型,PSPICE仿真结果与P矩阵理论结果在通带内吻合很好,并与实验结果相符,验证了所提出等效电路模型的正确性。     

Reliability Assessment of Microgrid Using Sequential Monte Carlo Simulation

Sequential Monte Carlo simulation method is introduced to the reliability assessment of microgrid,and a Weibuil distribution wind speed model is built to simulate the hourly wind speed of a specific site.Wind turbine generator model combined with a two-state reliability model is applied to Monte Carlo simulation method,and results show that the wind turbine reliability model works well with sequential Monte Carlo simulation.A two-state reliability model of micro gas turbine and a load model from IEEE reliability test system(IEEE RTS)are also introduced to the reliability evaluation of microgrid.Case studies show that Monte Carlo simulation method is flexible and efficient dealing with microgrid consisting of renewable resources with fluctuation characteristics.     

A new static induction thyristor (SITh) analytical model

In this paper, an analytical static induction thyristor (SITh) model is proposed based on device internal physical operating mechanisms. The nonquasi-static model predicts both device static and dynamic characteristics. The model accounts for effects of the device structure, lifetime, and temperature. Implemented in PSPICE as a subcircuit, model simulation results are compared with numerical simulation and experiment results for various electrical and thermal conditions. The model exhibits accurate results, good convergence, and fast simulation speed     

Study of electromagnetic wave propagation through dielectric slab doped randomly with thin metallic wires using finite element method

A new numerical simulation method using the finite element methodology (FEM) is presented to study electromagnetic propagation through a dielectric material slab doped randomly with thin and short metallic wires. The FEM approach described in many standard text books and published papers, is appropriately modified to account for the presence of thin and short metallic wires. Using this modified FEM approach, the transmission and reflection characteristics of a material slab (homogeneous dielectric slab doped randomly with thin and short metallic wires) placed in an X-band rectangular waveguide are estimated. The estimated results are compared with the numerical results obtained using the CST microwave studio simulation tool.     

SiGe HBT大信号扩散电容模型研究

基于SiGe HBT（异质结双极晶体管）大信号等效电路模型，建立了SiGe HBT大信号发射结扩散电容模型和集电结扩散电容模型．该模型从SiGe HBT正反向传输电流出发，研究晶体管内可动载流子所引起的存储电荷（包括正向存储电荷和反向存储电荷）的基础上，同时考虑了厄利效应对载流子输运的影响，其物理意义清晰，拓扑结构简单。将基于大信号扩散电容模型的SiGe HBT模型嵌入PSPICE软件中，实现对SiGe HBT器件与电路的模拟分析。对该模型进行了直流特性模拟分析，直流模拟分析结果与文献报道的结果符合得较好，瞬态特性分析结果表明响应度好。     

Warpage studies of HDI test vehicles during various thermalprofilings

New techniques and technologies involved in the miniaturization of printed wiring board (PWB) fabrication are rapidly emerging. The quality, performance, and reliability of surface mount assemblies built on these next-generation boards will depend on many factors, including thermally induced warpage. Therefore, quantitative warpage measurement is critical in new PWB assembly design evaluation, and determining overall thermal performance characteristics. Using an automated infrared reflow oven simulation system, the warpage of six bare high density interconnect (HDI) samples is measured under two different heating profiles. Out-of-plane surface displacement is measured with a noncontact shadow Moire technique and resolution enhancement method called phase-stepping. The two types of samples evaluated were built for the purpose of warpage study, where physical data could be used to validate finite element analysis (FEA) results. The warpage results obtained with the two thermal profiles will be presented     

Crosstalk fault modeling in defective pair of interconnects

The manufacturing defect in the interconnect lines can lead to various electrical faults, e.g. defect due to under-etching effect/conductive particle contamination on interconnect line can lead to increased coupling capacitances between the two adjacent interconnects, which, in turn, can eventually result in crosstalk fault in the deep sub-micron (DSM) chips. In this paper, we describe the line-defect-based crosstalk fault model that will be helpful in analyzing the severity of the defect/fault, as the crosstalk fault occasionally leads to various signal integrity losses, such as timing violation due to excessive signal delay or speed-up, logic failure due to crosstalk positive/negative glitch above/below logic low/high threshold and also reliability problem particularly due to crosstalk glitch above logic high threshold. Our crosstalk fault model is very fast (at least 11 times faster than PSPICE model) and its accuracy is very close to PSPICE simulation results when the defect/fault is located in the middle of interconnects, whereas for the defects located at the near-end/far-end side of aggressor-victim the model accuracy differs marginally.     

量子级联激光器的电路模型分析

通过分析量子级联激光器(QCL)中的电子在量子阱输运的单极行为,得到它的速率方程,以此为基础建立起它的等效电路模型,利用PSPICE进行电路模拟,得到了它的频率响应特性,并对可能影响它的调制特性的一些因素进行了分析.