一种电磁脉冲辐射系统设计

提出一种电磁脉冲辐射系统设计方案,此系统由Marx发生器、短路-锐化组合开关型脉冲形成线和带低频补偿的高功率超宽带横向电磁波(TEM)喇叭天线组成.Marx发生器产生的单极脉冲经过短路-锐化组合开关型脉冲形成线锐化成双极脉冲,然后馈入天线进行辐射.仿真结果表明,在充电电压为10 kV时,电磁脉冲源可产生脉冲宽度1.41...     

Generation and emission of high-power ultrabroadband picosecond pulses

The generation and emission of high-power ultrabroadband electromagnetic pulses are studied. The possibility of high-voltage (about 100 kV) bipolar voltage pulses with a duration of about 200 ps is demonstrated. The electromagnetic pulses with a FWHM of less than 100 ps, an effective potential of up to 400 kV, and a repetition rate of 100 Hz are generated using the 16-element antenna array.     

基于Marx发生器的紧凑型宽谱辐射源

采用Marx发生器作为脉冲功率源,用螺旋天线作为辐射系统,设计了一种紧凑型宽实验结果为:辐射场中心频率为171 MHz,2 m处最大辐射场为10.5 kV/m。谱辐射源,用于宽带天线技术研究。充电系统采用24 V锂电池逆变倍压产生几十kV的交流高压,给脉冲功率系统供电。10级Marx发生器设计为同轴结构,最大输出电压200 kV,整个Marx发生器尺寸为ф150 mm×550 mm。Marx发生器产生的脉冲经过辐射系统,最后通过螺旋天线辐射出去。     

Pulse Regeneration in the Gigabit-Per-Second Range Using a Diode Differential Regenerator

A clocked pulse regenerator circuit (diode differential regenerator (DDR)) is described which employs a modified hybrid tee, step recovery diodes, and bipolar transistors. For the first time a hybrid tee is used in ultra broad-band digital applications. Signal pulses with bit rates up into the gigabit-per-second range are regenerated, the shape of the input pulses having no direct influence on the shape of the output pulses. Only the charge of the input signals determines the amplitudes of the output pulses. At a signal bit rate of 1 Gbit/s an insertion voltage gain of 20 dB was obtained. Operating the DDR in a push-pull mode the voltage gain is doubled to 26 dB. Because the output pulses of the DDR are very narrow the circuit can be used in time-division multiplexers providing output pulse streams with bit rates up to 16 Gbit/s and amplitudes of several volts across a load of 50 Omega. The internal behavior of the DDR is analyzed, among other things by the results of computer simulations. Calculations for optimizing the employed components are given.     

Generation and shaping of megawatt high-voltage pulses byoptoelectronic technique

A composite miniature structure used to generate megawatt electrical pulses is described. Two photoconductive switches (one GaAs and the other Si) are used, along with voltage multiplication and pulse forming lines, to generate over 14-kV pulses from a DC bias of only 9 kV. These megawatt pulses have picosecond synchronization and can vary in width from nanoseconds to picoseconds     

铁氧体线电光开关

实验测量了铁氧体传输线对高压电脉冲的前沿锐化效应以及偏置磁化电流对电压波波前传输速度的影响。用二个被铁氧体线锐化后的脉冲相减,获得宽度连续可调、8kV的ns脉冲,以此驱动普克尔盒对调Q激光脉冲削波。     

3kV皮秒冲击波的产生

用非线性传输线（ＮＬＴＬ）压缩纳秒光电导开关输出电压脉冲的上升时间，获得３ｋＶ，小于４００ｐｓ上升沿的高压冲击波脉冲。简述了ＮＬＴＬ冲击波理论，介绍并分析了用电容ＮＬＴＬ产生高压冲击波脉冲的实施方法和结果。     

绝缘老化试验高压脉冲发生器的研制

介绍一种绝缘老化试验高压脉冲发生器的研制。此高压脉冲发生器结构选择模块化串联结构,采用MOSFET作为发生器的开关元件,可输出空载上升沿小于120ns、电压峰峰值0—10kV的方波脉冲。     

A model for electroluminescence in SrS:Ce ACTFEL display devices

An analytical model for electroluminescence in SrS:Ce AC thin-film electroluminescent display devices is presented. The model incorporates an exact calculation of the electric field and the effect of activator ionization and bulk traps. Activator ionization is needed to explain several features of luminescence behavior in SrS:Ce devices. These features include the second luminescence peak at the trailing edge of the voltage pulse and the time lag between the luminescence and the applied voltage when the applied voltage consists of bipolar trapezoidal pulses and rectangular pulses of low voltage amplitudes. As a mechanism for the ionization of activators, field-assisted tunneling is shown to be more likely than impact ionization by hot electrons. Physical processes are described in terms of rate equations, and field, current, and luminescence waveforms are calculated for one set of device parameters. The calculated and experimental luminescence waveforms agree     

A novel Smith-Purcell free electron laser

An experiment on a novel Smith–Purcell free electron laser (FEL) is described in this paper. The FEL is driven by a relativistic sheet electron beam of middle energy. The high frequency system of the device is a quasi-optical resonator composed of a diffraction grating and a three-mirror reflector. Coherent radiation with a peak power of tens of kW at the 3 mm waveband is sucessfully detected from an experimental facility. The main experimental parameters are: sheet beam energy from 400 kV to 500 kV; pulse length of voltage 70 ns; pulse beam current 0.2 kA; synchronous guide magnetic field up to 1.2 T with 10 ms pulse length; and grating period 2.2 mm.     

Electrostrictive Mechanism of Liquid Breakdown in Strongly Nonhomogeneous Field under the Action of Nanosecond Voltage Pulse

Electrostriction mechanism of breakdown in polar liquid caused by high-voltage nanosecond pulse is studied. Nonstationary motion of liquid in the pin-to-plane system exposed to a pulse with peak voltage of 30 kV and 6-ns duration is numerically analyzed. Cavities in which the breakdown can be initiated are formed in the vicinity of the tip electrode. Dimensions of such cavities are estimated, and the conditions for formation are formulated. Profiles of voltage and current pulses are measured for breakdown in water and air. The velocity of breakdown development in air is determined using the time delay of the pulse measured by the shunt of discharge current at several interelectrode distances. The proposed method has limitations in the measurement of breakdown in water due to the effect of displacement current that exceeds the discharge current.     

衍射输出相对论磁控管的高重频短脉冲运行实验研究

本文报道了近期衍射输出相对论磁控管在低电压、短脉冲、高重复频率条件下的初步实验研究结果。当外加电 压约180kV,磁场约0.12T 时,输出微波功率最高可达120MW,微波频率2.3GHz,功率效率22%。在半高宽约7ns,平 顶约2.5ns 的电脉冲条件下,输出微波底宽3ns,半高宽1.5ns。当器件以50Hz 和100Hz 高重复频率运行时,输出微波幅 值稳定性受电脉冲波动和通电螺线管内的电流波动影响较大,微波功率波动范围90MW 至120MW。以脉冲串的形式、 长时间高重频运行20000 炮次后,器件内部无明显的烧蚀出现。     

Optically achieved p-i-n diode switch utilizing a two-dimensionallaser array at 808 nm as an optical source

The design, fabrication, and application of optically activated switches is described. A 0.25-mm-thick Si p-i-n diode, 3.0 mm in diameter, was tested using an 808-nm 2-D diode laser array (measuring about 2 mm×5 mm) as an optical source. Preliminary testing of a 0.25-mm-thick device has demonstrated a holding voltage of 1000 V and a conduction of 10 A upon activation with 200 W of optical power (the pulse width was 10 μs). The same device, while being pulse biased to 2.0 kV, has demonstrated 20-A pulses (100-ns pulse width) with less than 10-ns risetime. The laser peak power was 500 W     

An improved control algorithm of shunt active filter for voltageregulation, harmonic elimination, power-factor correction, and balancingof nonlinear loads

This paper deals with an implementation of a new control algorithm for a three-phase shunt active filter to regulate load terminal voltage, eliminate harmonics, correct supply power-factor, and balance the nonlinear unbalanced loads. A three-phase insulated gate bipolar transistor (IGBT) based current controlled voltage source inverter (CC-VSI) with a DC bus capacitor is used as an active filter (AF). The control algorithm of the AF uses two closed loop PI controllers. The DC bus voltage of the AF and three-phase supply voltages are used as feedback signals in the PI controllers. The control algorithm of the AF provides three-phase reference supply currents. A carrier wave pulse width modulation (PWM) current controller is employed over the reference and sensed supply currents to generate gating pulses of IGBTs of the AF. Test results are presented and discussed to demonstrate the voltage regulation, harmonic elimination, power-factor correction and load balancing capabilities of the AF system     

全固态Bouncer调制器的设计

为改善调制器输出脉冲顶降,提出了一种基于绝缘栅双极晶体管串并联的全固态Bouncer调制器。介绍了全固态Bouncer调制器的基本原理和组成,分析了调制器工作过程,并给出了调制器工作时序关系;介绍了调制器Bouncer电路的设计,根据理论计算分析了影响电路参数的主要因素。文中设计的调制器要求输出脉冲电压50 kV,脉冲电流80 A,脉冲宽度1 ms,脉冲顶降小于1% 。根据调制器指标,分别给出了常规电容直接放电和Bouncer调制器的设计结果,并对Bouncer调制器进行了仿真,证实设计的全固态Bouncer调制器能够满足指标要求。     

周期极化LiNbO3晶片的制备工艺研究

采用外加电场法制备了周期极化LiNbO3单晶(PPLN),实现LiNbO3单晶周期极化的反向脉冲为24.3 kV/mm,单个脉冲宽度为30 ms,脉冲个数为50个。系统研究了脉冲波形、电极形状对周期极化的影响,实验结果证明,框形电极是克服高电压作用下LiNbO3晶片击穿严重的有效方法,成品率是采用梳状电极的5倍。选择合适的脉冲波形对成功制备周期极化的LiNbO3晶体有着极其重要的作用。采用上升时间为5 ms的方形脉冲极大地改善了高电压作用下的边缘被打碎而引发的边缘击穿,及由晶片中间部分出现微细裂纹而引发的体击穿。     

A four-channel IBM PC/AT compatible biphasic pulse generator fornerve stimulation

An IBM PC/AT compatible four-channel biphasic pulse generator has been developed to assist in functional electrical stimulation (FES) related research. Each channel uses a bipolar 12-bit digital-to-analog converter (DAC) to generate biphasic voltage pulses between +/- 5 VDC and three 16-bit timers to control first, second, and interphase durations. Two vectored interrupt generators are available for precise pulse timing control. Potential uses of this device include FES research, the characterization of the recruitment properties of percutaneous electrodes in multichannel stimulation systems, or as a subassembly in commercial medical devices requiring electrical simulation in an IBM PC/AT platform.     

从锁模脉冲序列中先后选出两个单脉冲的同步研究

采用再生放大腔内的短程放大,利用硅光导开关的长的复合时间,实现光导后产生快上升和下降时间、宽度可调的千伏电脉冲,完成从锁模脉冲序列中先后选出两个单脉冲,这两个单脉冲同步精度高、运转稳定。     

基于DP-LIBS铁合金中碳元素特征谱线的研究

采用双脉冲和单脉冲激光,对空气中标准铁合金样品中碳元素的激光诱导实验,研究两种方式下形成的光谱。双脉冲激光诱导击穿光谱采用两束激光,在第一束激光脉冲的基础上加入第二束高压激光脉冲,对等离子体进行二次激发。通过对比研究发现:双脉冲激发技术延长了原子特征辐射的有效时间,提高了获取信号的信噪比,增强了发射光谱的信号强度,提高了信号的稳定性。此外,通过分析影响双脉冲信号增强程度的因素,研究了脉冲宽度和延迟时间以及激发能级对光谱增强程度的影响。     

Multistreamer regime of GaAs thyristor switching

GaAs bipolar thyristors have been used to obtain current pulses of over 100 A with rise times less than 600 ps and load resistance of approximately 0.4 Ω. The maximum voltage has been shown to exceeded 500 V in some cases. To interpret the experimental results a multichannel switch regime is proposed. Analysis of the experimental data suggests the possibility of a further increase in the maximum amplitude of the current pulse