反向开关复合管的物理模型与数值方法实现

从大注入半导体物理的基本理论推导得到了反向开关复合管(RSD)工作的基本物理方程.通过考虑大注入和强电场效应,建立了RSD以pnn 二极管方式工作于反向预充阶段,以pin二极管方式工作于正向导通阶段的物理模型.采用有限差分法把器件工作的偏微分方程转化为差分方程,并将相应的边界条件转化为精度较高的离散化形式.结合RSD工作的典型电路建立电路方程组,采用Runge-Kutta方法求解,由非平衡载流子分布得到了RSD的电压、电流波形.通过RSD的放电实验与模型计算进行比较,分析了误差产生的原因,论证了物理模型本身及数值方法的合理性.通过应用电路说明了模型及算法的实用价值.物理模型和数值方法对于RSD器件设计及仿真电路的开发具有指导意义.     

大功率脉冲电源用超高速半导体开关RSD

新近开发出了用于大功率脉冲电源技术的新型超高速开关RSD，本文介绍了该器件的结构、开通机理、特性及测试实验结果。设计电流20KA、60KA、300KA，开通时间数十纳秒、断态重复峰值电压20～30KV的RSD堆已在实验室制出并在湖北襄樊仪表元件厂合作试生产。     

Evaluation study of different glass electrodes by an interlaboratory comparison for determining the pH of fuel ethanol

This work evaluated different combined glass electrodes by means of an interlaboratory comparison in order to determine the pH of fuel ethanol. Four electrodes with different reference electrode systems (Ag/AgCl or Pt/redox pair), liquid junctions (single or double) and internal filling solutions (aqueous KCl or ethanolic LiCl) were used in comparison with the Orion Ross Sure-flow^® N° 8172 BN electrode, a specific electrode advised by the ASTM D6423 standard. Three fuel ethanol samples with different water contents (0.1, 0.6 and 6.8%, w/w) were analyzed by nine laboratories. The results showed that all the electrodes with aqueous KCl filling solution and single liquid junction, including the Orion^® electrode, presented equivalent results. The sole electrode with ethanolic LiCl filling solution showed pH results lower than the other electrodes, whereas the sole electrode with double liquid junction, showed pH results slightly higher than those with similar filling solution containing single liquid junction. On the other hand, only the latter two electrodes presented acceptable repeatability limit values. The results indicate a need to revise the ASTM D6423 standard with the purpose of enlarging the number of electrodes that can be used to measure the pH of ethanol fuel, as well as support the harmonization of the different regional standards used to measure the pH of fuel ethanol.     

用于RSD脉冲电源的端电压翻转式触发电路

本文在RSD正常开通条件和谐振原理的基础上，提出了一种用于RSD(Reversely Switching Dynistor)脉冲电源的触发电路。主要讨论了该触发电路的参数设计，用快速晶闸管作为触发开关进行了实验，并给出了试验结果，验证了电路参数设计的合理性。     

用分光光度法测定含氨基酸类制品中的氨基酸含量

采用分光光度法对富含氨基酸类成分的制品中氨基酸含量的测定方法进行了研究探讨。试验主要利用氨基酸的氨基与茚三酮水合物反应可生成蓝紫色化合物,该化合物最大吸收峰在570nm波长处,且此吸收峰值的大小与氨基酸释放出的氨基成正比,因此可作为氨基酸定量分析方法。该方法简便、灵敏、快速,重现性良好,平均回收率为98.4%,RSD为1.0%,可用于食品(保健品)的产品检验方法。     

大功率半导体开关RSD触发用脉冲变压器的设计与研究

从RSD的结构原理出发,提出了采用可饱和脉冲变压器触发RSD的方案。并结合RSD触发要求,提出了该脉冲变压器设计中需满足的关键因素及设计方法。实验证明,采用可饱和脉冲变压器触发RSD是可行的。该脉冲变压器的设计方法也为设计更高电压等级的脉冲变压器提供了借鉴。     

高压RSD开关谐振触发的仿真

针对20kV高压反向开关晶体管RSD(Reverse Switching Dynistor)开关的触发问题,提出了一种谐振触发方式。利用电路仿真软件PSpice研究了谐振触发回路参数电容、电感、电阻对RSD预充电荷量的影响,并计算出相应条件下所使用磁开关的磁芯截面积。结果表明,谐振触发回路参数分别选择为0.3μF、8μH和1Ω时,能降低触发开关的要求,并能给RSD提供充分的预充电荷量。     

Effect of operating conditions and design parameters in a continuous powder mixer

An experimental investigation was carried out to study the mixing performance and flow behavior in a continuous powder mixer for a typical pharmaceutical mixture. Blender performance, characterized by the relative standard deviation (RSD) of composition of blend samples taken at the blender discharge and by the variance reduction ratio (VRR) of the blender, was measured as a function of impeller rotation rate, flow rate and blade configuration. The flow behavior in the continuous mixer was characterized using the residence time distribution (RTD) and powder hold-up measurements. To quantify the strain applied to the powder in the blender, the number of blade passes experienced by the powder in the blender was calculated using the residence time measurements. The relationship between different experimental parameters and mean residence time and mean centered variance was examined. The mixing performance was largely dominated by the material properties of the mixture, which had a larger effect than the ingredient flow rate variability contributed by the feeders. Holdup was strongly dependent on impeller rotation rate; as impeller rotation rate increased, holdup (and therefore, residence time) decreased sharply. As a result, intermediate rotation rates showed the best mixing performance. Blade configuration affected performance as well; blade patterns where some of the blades push the powder backwards improved the mixing performance.     

高效液相色谱法测定纽甜的含量

纽甜是一种新型高效、非营养型甜味剂,作为食品添加剂广泛应用在食品工业。对于纽甜产品的测量,目前尚没有国家标准,文章建立了用高效液相色谱法测定纽甜的含量,流动相为乙腈—缓冲溶液（体积比为25∶75）,流速1.5 mL/min,二极管阵列检测器（DAD）,柱温45℃。结果表明,纽甜质量浓度在1～10 mg/mL范围内甜与峰面积呈良好的线性关系,回收率在95.96%～99.90%。该方法简单、灵敏、准确,适用于纽含量的检测。     

用相对标准偏差和相对极差及测量极值比例确定分析检出限和定量限

检出限(LOD)和定量限(LOQ)对应的相对标准偏差可构成 RSDLOD(MAX)和RSDLOQ(MAX)两个临界值.通常采用的以测量10次样品空白标准偏差(SB)10倍作LOQ及以样品空白标准偏差3倍作LOD,在95％置信度下,实际测得的LOQ浓度和LOD浓度的RSD很容易超过其总体正态分布的理论值10％及33％.以...