具有谐振腔的多波切伦柯夫振荡器的粒子模拟

 设计了一种新型的多波切伦柯夫振荡器，即在第二慢波段和输出喇叭之间加一个谐振腔，并采用PIC方法模拟了器件产生微波的物理过程。结果表明这种新型器件符合普通多波切伦柯夫振荡器的基本特征，同时具有纵向尺寸短，导引磁场低，功率、效率高等优点。     

定速风力发电机模型参考自适应控制

在对定速风力发电机建模的基础上,设计了模型参考自适应控制器,并进行了跟随性能和抗干扰性能仿真,仿真结果表明自适应控制器的自适应能力很好.     

用于高功率激光装置中的电脉冲整形系统

采用射频GaAs场效应管和微带传输线技术,研制出用于高功率激光装置中的电脉冲整形系统.该系统电脉冲整形宽度为3.5 ns,幅度在0~5 V范围内调节,时域调整精度200 ps.整形后的方波,前沿383 ps,后沿642 ps,顶部不平坦度4~5%,波形幅度稳定性4~5%（p-p).利用该系统产生的整形电脉冲驱动电光波导调制器进行激光脉冲整形,得到了理想的整形激光脉冲.     

Evaluation of aerosol lead measurement techniques using laboratory generated super-micrometer particles

High levels of lead in some occupational environments still exist. These include lead paint abatement sites, smelting operations, small arms firing ranges, and other construction scenarios. New emerging technologies provide the capability to provide an on-site alternative to conventional laboratory methods for airborne lead. In this paper we describe the evaluation of two such technologies using laboratory prepared lead-laden super-micron aerosol particles. Size measurements by TSI Aerodynamic Particle Sizer™ indicated the fluctuation of the peak particle sizes varying less than 1% among different runs for a given solution concentration. The content of lead embedded in the particles varied from 14 to 18% between runs of three different lead solution concentrations. A commercially available instrument for airborne lead measurement, AeroLead™, showed promise of becoming fully validated with the addition of design enhancements, although not fully validated by the end of the research program. Some of these areas being reworked by the manufacturer include working electrode issues, such as a more uniform surface area. Once these have been addressed, the manufacturer plans to complete the field and laboratory validation procedures. In a subsequent study, the ABF-LIPS results shown in this paper indicated that the technology could be used to quantify lead in aerosol form with a signal-to-noise ratio of three or larger of approximately 100 μg m⁻³ or higher quantity in a few minutes of measurement interval. The estimated detection limit for Pb using the ABF-LIPS prototype was approximately 60 μg m⁻³. In comparison the Resource Conservation and Recovery Act (RCRA) limit for Pb emission is 250 μg m⁻³.     

自反Banach空间中C0-半群族的稳定性

主要讨论了自反Banach空间中一类C0-半群族{Th(t)}稳定性问题,证明了此类半群族{Th(t)}指数稳定与弱Lp-稳定是等价的.     

Evaluation of one‐ and two‐equation low‐Re turbulence models. Part II—Vortex‐generator jet and diffusing S‐duct flows

This second segment of the two‐part paper systematically examines several turbulence models in the context of two flows, namely a vortex flow created by an inclined jet in crossflow, and the flow field in a diffusing S‐shaped duct. The test cases are chosen on the basis of availability of high‐quality and detailed experimental data. The tested turbulence models are integrated to solid surfaces and consist of: Rodi's two‐layer k–ε model, Wilcox's k–ω model, Menter's two‐equation shear–stress‐transport model, and the one‐equation model of Spalart and Allmaras. The objective of the study is to establish the prediction accuracy of these turbulence models with respect to three‐dimensional separated flows with streamline curvature. At the same time, the study establishes the minimum spatial resolution requirements for each of these turbulence closures, and identifies the proper low‐Mach‐number preconditioning and artificial diffusion settings of a Reynolds‐averaged Navier–Stokes algorithm for optimum rate of convergence and minimum adverse impact on prediction accuracy. Copyright © 2003 John Wiley & Sons, Ltd.     

间接馈电的磁通量压缩发生器的参数选择

 从电路方程出发较详细地分析了间接馈电的磁通量压缩发生器的工作原理。分析表明：在设计间接馈电的磁通量压缩发生器时，只有馈电回路的电感L₁和电容C₀满足(L₁C₀)^1/2>>T时，MFCG才有效运行；耦合形式的MFCG能使初始磁通量放大；馈电回路电容大小的选择将影响MFCG输出的电流脉冲形状。这些结论对于设计磁通量压缩发生器具有指导意义。     

离散算子的本征投影与本征幂零

本文给出例子，说明离散算子本征投影一致有界推不出其本征幂零一致，有界幂零一致有界也推不出本征幂零的幂一致有界。     

高维Mbius群的分类、生成系统和离散准则

本文利用高维Ｍｏｂｉｕｓ变换的Ｃｌｉｆｆｏｒｄ矩阵表示，给出了高维Ｍｏｂｉｕｓ子群的一个分类定理，证明了非初等子群的最小纯斜驶生成系统的存在性，得到了一条离散准则。     

Vertex function and coupling constant for the virtual decay of7Li

The alpha-triton relative wave function with various nucleon exchange contributions and their asymptotic normalization are considered in the framework of the generator coordinate method (GCM). The asymptotic normalization of relative wave function provide the estimate of the coupling constant. The relative wave function is also used to obtain⁷Li-α-t vertex function in the virtual decay of⁷Li. The extrapolation of vertex function for negative values ofq ² up to the alpha-triton pole provide the vertex constant, which is compared with the experimentally determined estimates 0.67 FM and 0.72 FM. Our calculated value is 0.656 FM which is in close agreement with the above estimates.