电子束六维随机非线性状态方程及其任意阶近似解析解

在大型电子束设备中由大量电子组成的电子束在运动过程中,其纵向与横向都具有一定的分布,且具有相对论性、非线性及随机性等特征.其运动规律遵守相对论随机非线性六维状态方程.本文给出了空间坐标系为直角坐标时的相对论非线性随机性六维状态方程组及其任意阶解析解.     

自由电子激光器中的电子运动

用相对论量子力学对自由电子激光器中的电子运动作了分析,求得了螺旋泵浦磁场中Klein-Gordon方程的严格解析解.结果表明自由电子激光的增益饱和来源于出现退聚束效应及高阶聚束.     

磁旋管（综述）简介

(接 2 0 0 0第 6期第 1 2页 )4　动力学理论参考资料 [2 ]和 [3]由动力学理论获得一些计算公式 ,可用于磁旋管各部分的设计计算。有些公式可能有误 ,请使用时详细推导一下。4.1　偏转系统磁旋管中电子注的圆偏转由激励 TM110 振荡的圆柱腔的 RF磁场实现。TM110 的场结构如图 2所示。因为需要得到大的偏转角引起增益下降和电子能量散开 ,采取纵向磁场克服了这个缺点。电子运动旋转方向应和 RF场一致。在小偏转角近似下可得解释解。假设βz=β0 =常数 ,γ=γ0 =常数 ,在迪卡尔坐标系中有 :dvxdt=- emγ[vx Bz- vz By]dvydt=- emγ[vz Bx-…     

用两种方法研究纯追踪攻击曲线

分析和计算的空间问题,一般可采用两类坐标系:笛卡儿直角坐标系和极坐标系。针对研究目标匀速直线运动时的纯追踪攻击曲线用传统的D-q极坐标分析时没有解析解的缺陷,本文介绍了用x-y坐标解决这个问题的方法。     

基于坐标转换法研究三振子圆极化天线

文中通过直角坐标转换的方法，分析了一种三振子天线．通过推导出的解析解，对圆极化天线进行了Matlab仿真，发现该天线在两个坐标平面上都为圆极化场，可以在这两个平面法线方向同时进行极化分集接收，改善通信质量。     

二极管方程新的解析近似解

提出了二极管方程一种新的解析近似解。使用精确的一阶及二阶微分和改进的牛顿-拉夫森方法,推导出一个简洁的二极管方程解析近似解。较之先前的二极管方程解法和近似,该解析近似解显著提高了二极管电流计算的精度和效率。同时,用户在将MOSFET模型如ACM、EKV和BSIM5中的二极管模型和反型层电荷模型实现到诸如SPICE等电路仿真模拟器中时,该解析近似解提供了高精度和高效率的计算方法。     

利用AWE技术计算各向异性阻抗劈的绕射场

平面波斜入射到各向异性阻抗劈时,由于出现电场和磁场的"耦合"问题,采用一般的一致性几何绕射理论(UTD)方法,无法得到绕射场的解析解,而一些近似方法也只能得到小角度偏离正入射或者掠入射情况下的近似解.采用渐近波形估计(AWE)技术,从已有结果的斜入射角度范围上进行外推,得到其他角度的近似解,从而得到更一般情况下各项异性阻抗劈的绕射场结果.     

紧束缚带半导体中载流子浓度和费米能量解析近似研究

本文给出了紧束缚带半导体中载流子浓度和费米能量之间的解析近似表达式。借助贝塞尔函数我们获得载流子浓度的系列展开公式，该公式具有快速收敛性。采用高斯积分方法获得了简单和高精度的费米能量解析近似表达式。由解析公式计算的结果与精确数值解吻合得很好，精度为10^-5量级。该解析公式可以方便地用于计算微带超晶格的电子输运和超晶格器件模拟。     

均匀外磁场中铁质球体系统磁场的镜像解析解

均匀外磁场中铁质球体系统磁场的计算一般是比较困难的,这是因为铁质球体之间的相互磁化比较难处理.从点磁荷与磁介质球系统中的镜像法出发,对磁介质球中的镜像线磁荷进行简化等效,推导出铁质球体系统中镜像磁偶极子和镜像磁荷的表达式.然后计算铁质球体之间各阶相互磁化而产生的附加磁场,进而求出铁质球体系统磁场的镜像解析解,并分析讨论了镜像解析解最大阶数的选择.仿真实验结果表明,镜像解析解的误差非常小,且适用于各种相对磁导率下铁质球体系统磁场的计算.     

两种正交曲线坐标系单位矢量间的一般表达式

本文采用不同的分析思路,导出了曲线坐标系与直解坐标系单位矢量间简明的解析关系,并推广到更一般的情况－－任何两种正交曲线坐标系单位矢量间的关系,只要一种正交曲线坐标系与直解坐标系或另一种正交曲线坐标系坐标间的简值关系已知,利用这些关系式即可得到正交曲线坐标系与直解坐标系或另一种正交曲线坐标系单位矢量间的关系,利用文献上已有的正交曲线坐标系坐标间的单值关系,文中提供了正交曲线坐标系与直角坐标系及圆柱坐标系单位矢量间的变换矩阵,进而可得任何两种正交曲线坐标系单位矢量间的关系。     

Analysis for the new type long-pulsed and high efficient microwave amplifier—magnicon

This paper begins with the cylindrical cavity field expression of the rotating TM_n10 mode in magnicon, and obtains its dissipated power, cold quality formula and so on, which are different from those in the static state TM_n10. Furthermore starting from the dynamics equations, the passive deflect cavity electron velocity and position solution, as well as the interact instantaneous power solution between electron and wave have been solved. The cylindrical coordinate electron energy dynamics equation in the output cavity, and the modification of terminal parameter formula for relativity have also been discussed.     

新型长脉冲超高效放大器Magnicon研究

文章简述了Ｍａｇｎｉｃｏｎ磁旋管的来源和发展过程，概述了它的原理。磁旋管放大器使用直圆柱谐振腔。本文从腔内旋转ＴＭ（ｎ１０）场的表达式出发，给出了谐振腔的欧姆损耗功率、冷Ｑ等的计算公式。它与现有的静态ＴＭ（ｎ１０）模场的相应公式不同，而后者目前仍被用于磁旋管的设计。文章从电子动力学方程出发，求得无源磁偏转腔的电子速度和位置解（位置与现有的不同），求得偏转腔中电子束与波的相互作用瞬时功率解。文中还给出输出腔柱坐标系的能量动力学方程，输出腔末端参数公式的相对论修正系数，以补充现有的非相对论公式。     

Analytical solution and frequency extraction of iris problems inwaveguide by separation of variables

The field nearby a thin iris discontinuity can be found in an exact manner by solving the wave equation in an appropriate coordinate system. To this end, it is necessary to select a coordinate system that fits the iris boundary. As an example, capacitive and inductive irises in rectangular waveguides have been solved by considering the Helmholtz equation in the elliptic-cylinder coordinate system. The presence of the waveguide environment is then enforced either by using the aperture field solution in a variational expression of the equivalent shunt susceptance or by taking images. The advantage of the new solution is that a single term solution, apart from being very accurate and numerically efficient, also contains the correct frequency dependence; thus providing results over the entire band. Moreover, wide-band equivalent circuits with frequency independent elements of the Foster's canonical form descend directly from the field analysis     

Comparison of TDOA location algorithms with direct solution method

For Time Difference Of Arrival (TDOA) location based on multi-ground stations scene, two direct solution methods are proposed to solve the target position in TDOA location. Therein, the solving methods are realized in the rectangular and polar coordinates. On the condition of rectangular coordinates, first of all, it solves the radial range between the target and reference station, then calculates the location of the target. In the case of polar coordinates, the azimuth between the target and reference station is solved first, then the radial range between the target and reference station is figured out, finally the location of the target is obtained. Simultaneously, the simulation and comparison analysis are given in detail, and show that the polar solving method has the better fuzzy performance than that of rectangular coordinate.     

相对论电子在周期磁场中的辐射频谱

分析了相对论电子在空间周期磁场中的运动轨迹.在一定条件下,电子在垂直原始入射方向上的运动是简谐的,利用谐振子模型求出了它的辐射频谱和频宽;最后讨论了运动的非谐性.得到辐射频谱分布将是与电子的初速度、磁场强度有关.     

Geometric-Polar Tracking From Bearings-Only and Doppler-Bearing Measurements

Bearings-only tracking (BOT) and Doppler-bearing tracking (DBT) perform target motion analysis from measurements of bearings, Doppler and bearings, respectively. The state equations are simple for both the target and observer in the rectangular coordinates. Hence, BOT and DBT mostly work in that coordinate. By developing the trigonometric relations between target and observer postions over time, this paper first derives the pseudolinear equations for direct range and bearing estimation. It then provides a generalized total least squares (GTLS), and a maximum likelihood solution. Polar tracking has two advantages over rectangular. First, for applications that require range and bearing, polar output avoids a coordinate conversion at every output instant. Second, polar equations often have a smaller bias than rectangular. Consequently, polar estimates can give a closer (to the optimum) initialization for iterative algorithms. Simulation results have validated the theoretical development, confirming the near optimality of the GTLS and maximum likelihood solutions.      

Model of a nonlinear electromagnetic crystal

2D electromagnetic crystal with lumped nonlinear elements is considered. An electrodynamic model with a rectangular grid is developed for a crystal that is infinite in one coordinate and finite in the other. In the case when the structure is excited by a plane wave, linear boundary value problems are formulated for electromagnetic fields at multiples of the fundamental frequency. The nonlinear problem is solved by means of the harmonic balance method. A system of nonlinear equations for the amplitudes of voltage harmonics at nonlinear elements is derived. Results of numerical solution of the system are presented for resistive and capacitive nonlinear elements.     

微机界面动态图的坐标变换及稳定性设计

基于微机原理中汇编语言程序执行的实时性特点,设计了在微机显示器屏幕上画直角坐标系下的动态变化图.采用数学变换的形式,克服了微机显示器屏幕的坐标与直角坐标系不一致的问题,同时解决了换页时出现的图形变乱问题.以工程实际为例,在显示器上画出实时的跟踪风速随时间变化的正弦曲线图.     

同轴腔电子回旋微波激射器电子效率的研究

通过非线性模拟计算同轴腔电子回旋微波激射器的电子效率,结果与德国卡尔斯鲁研究中心研制的同轴腔电子回旋微波激射振荡器的实验效率比较吻合,进而通过提高初始横纵向速率比和引入坡度磁场,使器件的电子效率从26.7%提高到34.6%.这种效率放大的物理机制是:坡度磁场改变了相对论电子的运动条件,有效地改善了波束互作用过程中电子的群聚状态,从而提高了电子束的换能效率.     

Analysis of the zonal and rectangular slots on a conductingspherical cavity

The zonal slot cut on a conducting spherical cavity is analyzed rigorously. The slot is excited asymmetrically, which excites higher order azimuthal modes. The Green's function approach is used to formulate an integral equation for the magnetic current in the slot, which is solved using the moment method (MoM). New recurrence formulas are derived so that within their stable region the admittance integrals can be evaluated without the need for any numerical integration. In this case, the solution is very easy to implement with extremely short computation time. The effects of the latitude angle on the peak resistance and percentage bandwidth are investigated. Furthermore, the cavity resonance modes and their degeneracy are examined by plotting the expansion coefficients of the magnetic current. In addition, the problem of a rectangular slot in the nonequatorial plane is also studied. Measurements are carried out and good agreement between theory and experiment is obtained