100kV触发器输出脉冲的陡化

快前沿的高电压脉冲在脉冲功率技术领域具有重要应用,使用快前沿的触发信号触发气体火花开关,能有效减小气体开关的抖动,使Marx发生器的输出抖动减小,从而有利于多台Marx发生器的精确同步并联工作。为利用陡化回路将触发器的输出电压脉冲进行陡化以得到快前沿的高压脉冲,分析陡化回路的工作原理后针对100 kV触发器设计了陡化器。确定了陡化器内可以使用的不同电极结构陡化开关的相关测量方法,研究了气体种类、电压大小以及电极结构这些因素对陡化回路工作性能的影响。当陡化回路选用间隙为5mm的尖电极陡化开关、陡化开关内充入0.60~0.90 MPa的N2、触发器主电容充电55 kV时,幅值为90 kV的电压脉冲其前沿从20ns降低为2.3 ns。研究结果表明:陡化开关内使用N2,适当提高输入脉冲电压幅值并增大陡化开关场强时,陡化回路的陡化效果更好。     

Modeling Methods for the Main Switch of High Pulsed-Power Facilities Based on Transmission Line Code

Based on the transmission line code （TLCODE）, a circuit model is developed here for analyses of main switches in the high pulsed-power facilities. With the structure of the ZR main switch as an example, a circuit model topology of the switch is proposed, and in particular, calculation methods of the dynamic inductance and resistance of the switching arc are described. Moreover, a set of closed equations used for calculations of various node voltages are theoretically derived and numericMly discretized. Based on these discrete equations and the Matlab program, a simulation procedure is established for analyses of the ZR main switch. Voltages and currents at different key points are obtained, and comparisons are made with those of a PSpice L-C model. The comparison results show that these two models are perfectly in accord with each other with discrepancy less than 0.1%, which verifies the effectiveness of the TLCODE model to a certain extent.     

锰对改善 CaBi4Ti4O15高温压电陶瓷性能的研究

采用固相法制备了Mn改性的CaBi4Ti4O15(CBT xmol%MnCO3)层状压电陶瓷.介电温谱显示所有样品居里点在780℃附近,并且发现该材料在110K处有一介电弛豫峰.Mn的加入显著降低了高温下的介电损耗,剩余极化轻微降低,室温介电常数从173减小到162,同时机械品质因子由2700增加到4400,显示了硬性掺杂的效果.在100～600℃范围内,x=1.0的样品比纯组分的电阻率提高了一个数量级以上,500℃的电阻率提高了约2个数量级(108Ω·cm),电阻率对温度的Arrhenius拟合由两段过渡到三段,压电系数d33由7提高到14.5.实验结果表明,Mn改性的CBT在高温传感器等领域具有应用前景.     

百ns直线型脉冲变压器模块仿真及初步试验

短脉冲直线型脉冲变压器(LTD)是近年发展的一种新型脉冲功率驱动源新技术,LTD模块化后可方便地串、并联使用。为了紧跟国际上短脉冲LTD技术,进一步拓宽其应用领域,介绍了LTD的基本原理后根据国内脉冲电容器、高频磁芯和绝缘子的技术水平,提出了一种电流上升时间约100ns、电流峰值约100kA的一级LTD模块的技术方案;重点介绍了设计模块的结构及磁芯材料的选取;利用通用电路仿真软件Pspice建立了相应的模拟电路模型,并计算了输出参数;在充电±35kV时对设计方案进行的一路单元初步实验中得到短路电流幅值7kA,上升时间(10%～90%)约86ns,单个回路电感约270nH。实验结果表明,设计方案能达到预期指标。     

BiAlO3掺杂PZT陶瓷的高压电性能和低电场应变滞后

铅基压电陶瓷因其优异的压电性能, 被广泛应用于压电器件。其中, 压电驱动器要求压电陶瓷具有较高压电性能并且在电场下具有较高的电致应变和较小的应变滞后。本研究通过施主-受主共掺, 得到高压电性能和低电场应变滞后的PZT陶瓷。采用传统固相反应法制备了(1-x)(Pb_0.95Sr_0.05)(Zr₅₃Ti₄₇)O₃-xBiAlO₃+0.2%MnO₂陶瓷(掺杂量为质量百分数), 并对其微观结构和压电性能进行了研究。结果表明：BiAlO₃掺杂量较少时, 陶瓷中缺陷偶极子的“钉扎”效应使得陶瓷畴壁转动困难, 陶瓷压电性能较弱, 应变滞后也较小。随BiAlO₃掺杂量增加, 缺陷偶极子“钉扎”效应减弱, 陶瓷的压电性能和应变滞后随之提高。本实验得到的性能最优组分为x=1.75%, 该组份陶瓷的压电系数d₃₃=504 pC/N, 机电耦合系数k_p=0.71, 机械品质因数Q_m=281, 居里温度T_C=312 ℃, 在10 kV/cm电场下的应变滞后仅为15%, 并且还具有较好的温度稳定性, 是一种具有应用价值的压电驱动器用压电陶瓷材料。     

多级多通道低电感火花气体开关

简述了几种多级多通道低电感火花气体开关 ,分析了该类气体开关的设计原则 ,提出了一种中间电极采用不锈钢弹簧、触发电极位于主放电通道之外的同轴状气体开关的设计思想 ,初步试验表明 ,设计可行 ,开关电感较小。     

Ultra Fast Shutter Driven by Pulsed High Current

Radiation simulation utilizing plasma radiation sources (PRS) generates a large number of undesirable debris, which may damage the expensive diagnosing detectors. An ultra fast shutter (UFS) driven by pulsed high current can erect a physical barrier to the slowly moving debris after allowing the passage of X-ray photons. The UFS consists of a pair of thin metal foils twisting the parallel axes in a Nylon cassette, compressed with an outer magnetic field, generated from a fast capacitor bank, discharging into a single turn loop. A typical capacitor bank is of 7.5 μF charging voltages varying from 30 kV to 45 kV, with corresponding currents of approximately 90kA to140 kA and discharging current periods of approximately 13.1 μs. A shutter closing time as fast as 38 microseconds has been obtained with an aluminium foil thickness of 100 micrometers and a cross-sectional area of 15 mm by 20 mm. The design, construction and the expressions of the valve-closing time of the UFS are presented along with the measured results of valve-closing velocities.     

改良的DHX工艺在丙烷回收装置中的应用

为回收油气田中的丙烷,以现有专利DHX工艺为基准,提出两种丙烷回收改进工艺,并运用HYSYS对3种工艺进行了模拟和分析。结果表明:3种工艺均能满足丙烷回收率大于98%和脱乙烷塔塔底乙烷/丙烷比值小于等于1.6%的指标要求。专利DHX工艺复杂,采用丙烷冷冻系统,设备投资成本高。改良的DHX工艺Ⅰ和Ⅱ取消了丙烷制冷系统,简化了流程并且降低了设备投资。相对于改良方案Ⅰ,改良的DHX工艺Ⅱ干气出口压缩机的能耗增大47%;即从能耗及操作性角度而言,改良的DHX工艺Ⅰ既优于专利DHX工艺也优于改良的DHX工艺Ⅱ,建议丙烷回收装置采用改良的DHX工艺Ⅰ,可使丙烷高产出又经济低能耗。     

Optimization of Cavity Combination for 20 MA LTD-Based Accelerators

Based on a transmission line code,a circuit model is proposed that could serve as the basic method for the analysis of linear transformer driver (LTD)-based accelerators.By using 1MA,100kV LTD cavities,the peak load current is optimized for a total of N cavities between 500 and 1200.The simulation results suggest that,with the same number of cavities,the peak current changes obviously with the types of combinations,and the maximum change can be as large as 1.2MA.The results also show that,for the cases considered,the optimized peak current as a function of the total number of cavities agrees with the exponential associate,and the peak current for one level LTD cannot be enhanced infinitely.Furthermore,it is found that,to obtain a 20MA peak load current,at least 1029 LTD cavities (49 in series and 21 in parallel connection) are needed.Finally,the typical parameters of the optimized design are compared to those of the existing Z accelerator.     

铌镁酸铋钛酸铅压电陶瓷准同型相界附近的性能和相变温度研究

利用传统固相烧结法制备了Bi(Mg2/3Nb1/3)O3-PbTiO3(BMN-PT)压电陶瓷,分析了不同PbTiO3含量对BMN-PT压电陶瓷的晶体结构、介电、压电及铁电性能的影响.XRD结果表明:合成的BMN-PT陶瓷具有纯钙钛矿结构,并且在PbTiO3含量为x=0.60时,其组分的XRD图谱在衍射角2θ=45°出现明显的分峰,说明该组分相结构中存在三方和四方相的共存.压电铁电性能显示,BMN-0.60PT有最大的压电常数d33(～170pC/N)和平面机电耦合系数kp(0.35),最小的矫顽场Ec(29.4 kV/cm)及最大的剩余极化Pr(31.4μC/cm2).确定了BMN-PT压电陶瓷的准同型相界(MPB)为PbTiO3含量x=0.60的组分.介电系数温谱表明介电系数峰值温度(Tm)随着PbTiO3含量的增大而升高,MPB组分的Tm约为276℃.