基于TTL数字电路控制的高压脉冲源

给出了一种基于TTL数字电路作为高压脉冲源触发控制单元的设计原理和方法。介绍了高压脉冲源的工作原理,设计了一台脉冲输出幅度5 kV、脉冲宽度大于200 s及脉冲前沿小于30 ns的高压脉冲源。将触发控制单元和前级开关金属氧化物半导体场效应管（MOSFET）组合成一体,控制后级气体高压开关管放电输出高压脉冲信号。实验结果验证了所采用的设计原理及方法的可行性,给出了单次触发情况下的实验结果。     

100 kV重复频率高压脉冲电源

为研究气体间隙的放电特性,设计了输出幅度在30～100 kV、重复频率1～5 kHz可调的高压脉冲电源。利用谐振充电的原理,将10 kV的初级电源的能量转移到中储电容,中储电容的电压升高到至少18 kV。在光触发信号的作用下,氢闸流管导通,中储电容上的能量通过脉冲变压器放电,在脉冲变压器的副边得到最大幅度为100 kV的负脉冲,其脉宽大于200 ns,前沿时间小于90 ns。整个装置在不加散热系统的情况下,可连续工作1 min以上。     

KDP晶体前表面修复轮廓的光强调制能力影响

在高功率激光系统中,精密微机械修复是减缓磷酸二氢钾（KDP）晶体表面缺陷增长的有效方法,使用精密微铣削机床可以加工出球面型与高斯型修复轮廓。为得到最优的修复结构参数,建立了晶体前表面球面型与高斯型修复轮廓的电磁场有限元模型,通过改变轮廓的宽度、深度等参数,对两种修复轮廓的光强调制能力进行对比研究。仿真结果表明光强调制能力主要是由修复轮廓的衍射效应及入射光在修复界面处的二次入射所引起的干涉作用共同决定;针对初始损伤点,建议采用宽深比大于5的修复轮廓,从而有效提高KDP晶体表面缺陷点的激光损伤阈值,对于宽深比大于10的修复轮廓建议选用高斯型;对宽1000 m,深20 m的两种修复表面的激光损伤实验表明,高斯型修复轮廓具有较高的抗损伤能力,实验与仿真结果相一致。     

单官能团分子在缩聚反应中对分子量及其分布的影响

本文建立了单官能团分子对A-B 型、A-A、B-B 型二类线型缩聚反应产物的分子量分布影响的偏微分方程,并用Laplace 变换法求解,得到此二类缩聚反应类型的分子量分布.文中还详细讨论了缩聚反应产物中端基结构不同的分子的分子量分布.     

长波正则方程的广义差分法

讨论长波正则（ＲＬＷ）方程的初边值问题的广义差分法，证明半离散和全离散格式的稳定性与收敛性。     

Bundling strategies for platforms with an installed base

As an emerging platform, hardware/software platforms differ from traditional retail platforms because they require consumers to spend a certain amount of money accessing them. Therefore, an installation base is created. Considering the game console as an example, only consumers with an installation base can purchase a third-party game product on the platform. Otherwise, consumers will be unable to play games. It is generally believed that the existence of an installed base will benefit third-party content providers, and at the same time, it will not benefit platform manufacturers. Therefore, it can be observed that game platforms often bundle new consoles with third-party content, forcing consumers with installed bases to purchase a new console. Thus, building a model to study the impact of the installation based on the bundling strategy of the video game platform and to analyze the optimal pricing and profit under different bundling strategies is meaningful. Our study analyzed the impact of the installed base under different bundling strategies and found that the installed base dose not always have a positive impact on platform manufacturers. The study also analyzed the equilibrium of competing platform manufacturers and found that, under certain conditions, both the bundling-bundling strategy and the unbundling-unbundling strategy may exist as equilibrium.     

益肾方对db/db糖尿病小鼠肾保护作用的疗效观察

目的:探讨益肾方对db/db糖尿病小鼠肾保护作用的效果.方法:60只db/db糖尿病小鼠随机分为模型组、益肾方低剂量组、益肾方高剂量组和洛汀新组,15只同背景db/m小鼠为正常对照组,分别灌胃12周,检测肾功能相关生化指标,并对肾组织进行HE、PAS染色.结果:与对照组相比,模型组、益肾方低剂量组、益肾方高剂量组和洛汀...     

100 kV重复频率高压脉冲电源

为研究气体间隙的放电特性,设计了输出幅度在30～100 kV、重复频率1～5 kHz可调的高压脉冲电源。利用谐振充电的原理,将10 kV的初级电源的能量转移到中储电容,中储电容的电压升高到至少18 kV。在光触发信号的作用下,氢闸流管导通,中储电容上的能量通过脉冲变压器放电,在脉冲变压器的副边得到最大幅度为100 kV的负脉冲,其脉宽大于200 ns,前沿时间小于90 ns。整个装置在不加散热系统的情况下,可连续工作1 min以上。     

Visualization of an adsorption model for surfactant transport from micelle solutions to a clean air/water interface using fluorescence microscopy

The micro- and mesoscopic structure of reverse Pluronic 25R4 in aqueous mixtures has been studied by SANS, SAXS and shear rheology. These techniques have been able to give a deep insight into the complex structure of the system phase diagram, that includes an isotropic water-rich liquid phase L(1), and liquid crystalline phases with hexagonal, E, or lamellar order, D. Particular attention has been paid to the isotropic water-rich phase L(1), which has a large stability region in the temperature-composition phase diagram. This region is crossed by a large "cloudy zone". Below it, namely at low temperature and composition, SANS data show the presence of polymer unimers in a gaussian coil conformation. Above the "cloudy zone", at higher temperature and composition, the L(1) phase is structured as a network of interconnected multimeric micelles. Rheology adds information about the structuring of the L(1) phase showing its incipient hexagonal pre-structuring. This technique is also able to highlight the defective structure of the E phase itself. In the temperature and concentration ranges in which a lamellar phase D is present, SANS and SAXS results are in complete agreement, showing how interlamellar distance is influenced by both polymer composition and temperature according to an "ideal deswelling" or a "not ideal swelling" mechanism. In addition, in the D phase rheology suggests the presence of densely packed vesicles.     

Effect of Xanthan Gum on the Performance of Aqueous Film-Forming Foam

Solution properties of aqueous film-forming foam (AFFF) formulations containing different xanthan gum contents were investigated first by varying the mass fraction of xanthan gum in the range of 0.1–0.5%. Foam properties and fire-extinguishing performance of the AFFF formulations were then evaluated. Results indicated that xanthan gum content slightly affected surface tension of foam solutions. However, xanthan gum significantly affected viscosity of AFFF concentrates. Foaming of the AFFF formulations was hardly affected by xanthan gum, but foam stability of the compounds was obviously enhanced with the addition of xanthan gum. Optimal xanthan gum content was determined as 0.3%, which resulted in the shortest 90% control time and fire extinguishment time. Burnback time of foams increased with the addition of xanthan gum because of the enhanced foam stability.