Field Patterns of the TE Modes in Ridge-Trough Waveguide

A single-ridge waveguide with a symmetrical longitudinal trough, designated as a ridge-trough waveguide has been used as a transition in a V-band (50-75 GHz) wafer probe recently. In this paper, the field patterns for the dominant TE mode and the first higher TE mode in ridge-trough waveguide with different configurations are presented by finite element method. The field patterns in this paper have important values for us to understand the transmission characteristics of ridge-trough waveguide, and will be of practical significance in designing ridge-trough waveguide components in microwave and millimeter wave engineering.     

阿尔芬波加热研究的进展

本文概述了阿尔芬波加热的理论和实验情况。讨论了阿尔芬波加热的基本物理问题,并介绍了某些重要的实验结果。对在大托卡马克上采用阿尔芬波加热的可能性进行了全面论述。     

一个新的IEC61000-4-2标准ESD电流解析表达式

 分析了两个ESD标准电流波形表达式，并提出一个新的基于脉冲函数来描述ESD标准电流的解析表达式，该表达式符合最新的标准IEC61000-4-2，在零时刻的电流及其微分部为0，且波形与实际测量波形基本吻合。     

A model for single heterostructure field effect transistors

Single heterostructure field effect transistors are studied within a proposed analytical model for the heterostructure conduction band potential profile. An expression for the bias potential closing the conduction channel between drain and source is derived as a function of growth parameters and bias. In particular we study a field effect transistor based on Al_xGa_1−xN/GaN. The quantum well potential is modelled along the lines of the local density Thomas-Fermi approximation with the inclusion of exchange effects. Recent experimental results on two-dimensional electron gas density in this kind of systems are explained.     

Radiation damping in closed expanding universes

The dynamics of a coupled model (harmonic oscillator-relativistic scalar field) in Conformal Robertson-Walker (k = +1) spacetimes is investigated. The exact radiation-reaction equation of the source-including the retarded radiation terms due to the closed space geometry – is obtained and analyzed. A suitable family of Lyapunov functions is constructed to show that, if the spacetime expands monotonely, then the source's energy damps. A numerical simulation of this equation for expanding Universes, with and without Future Event Horizon, is performed.     

Effect of unidirectional solidification rate on Jc for current lead

The dependence of transport J_c value on the traveling rate and the nominal composition was investigated by taking different nominal compositions of YBa₂Cu₃O_6+x (Y123) + n mol% Y₂BaCuO₅ (Y211) (n = 10, 20, 30, 40 and 50) with addition of 0.5 wt% of Pt on samples processed by different unidirectional solidification rates, namely 1, 3 and 5 mm/h. The highest J_c was found in the sample with 30% Y211 addition by the higher traveling rate adjusted to prevent the formation of polycrystals. In this φ 1.56 × 60 mm sample the values of transport I_c and J_c were 1370 A and 71 700 A/cm², respectively, which were obtained by the conventional DC four-probe method with criterion of 1 μV/cm at 77 K and self-field.     

HL—1装置的低q放电实验

装置获得的最低qL值是衡最托卡马克磁流体不稳定性的控制水平的重要品质参数.通过精细调节补充送气和电流上升率的方法控制电流密度分布,使用钛吸气方法控制边缘等离子体参数,HL-1装置获得了最低qL值为1.8的稳定等离子体。实验结果表明,若电流上升率与密度上升率之比为(23—40)×10~(-19)kA·m~3的范围内,最利于获得低MHD增长率的稳定放电。预计这与中心q(0)<1峰化的电流密度分布有关。     

Poisson过程作为更新过程的若干新的特征刻画

本文将给出Poisson过程作为更新过程的一系列新的特征刻画．这些刻画是借助于更新过程中所有关键量的条件概率分布或条件期望来表述的．所给的条件是至任一指定时刻发生的抵达敷为已知．     

非线性广义系统平衡点的定性分析

本文研究非线性广义系统平衡点的定性行为．利用系统的正则性，证明了可以通过其线性系统的定性行为研究非线性系统的定性性态，为定性研究非线性系统提供了一种方法．     

Unscented fuzzy-controlled current statistic model and adaptive filtering for tracking maneuvering targets

A novel adaptive algorithm for tracking maneuvering targets is proposed. The algorithm is implemented with fuzzy-controlled current statistic model adaptive filtering and unscented transformation. A fuzzy system allows the filter to tune the magnitude of maximum accelerations to adapt to different target maneuvers, and unscented transformation can effectively handle nonlinear system. A bearing-only tracking scenario simulation results show the proposed algorithm has a robust advantage over a wide range of maneuvers and overcomes the shortcoming of the traditional current statistic model and adaptive filtering algorithm.