振荡方程

This paper, with the analysis of the propagation characteristics in a lossy cylindrical waveguide and using small-signal theoretical dispersion relation, presents study on the device stability with influence of the absolute instability and the backward wave oscillation in TE01-mode lossy dielectric-load gyrotron traveling wave amplifier.

摘要该文从分析损耗介质加载金属圆波导中电磁波传输特性出发，应用回旋行波管放大器小信号色散方程，研究损耗介质加载结构TE01模回旋行波管放大器绝对不稳定性振荡和回旋返波振荡对器件稳定性的影响。

The static model of torsion joint is based on that of bending joint. The effects of structure parameters inside air pressure, initial angle, rube average radius, rube shell thickness on the turning angle are analyzed and the following conclusions are drawn: the relationship between the angle of torsion joint and the inside air pressure is basically linear, the angle of torsion joint increases with the initial angle and rube average radius, the angle of torsion joint decreases while the rube shell thickness increases. The kinetic equation is built for torsion joint. Simulating experiment implies that the time of inflating and deflating process is extremely shorter than that of kinetic process. So the pneumatic process can be ignored in actual system design and control. The factors that affect the dynamic features of torsion joint, such as shell thickness of rubber tube, average radius, initial angle, connector's outlet area, moment of inertia and viscous damping coefficient, are analyzed and the following conclusions are drawn: the change of rube shell thickness has no effects on the dynamic process of FPA inside air pressure while greatly affects the turning angle of torsion joint; when the rube shell thickness is small, the torsion joint has a bigger turning angle, no overshoot and long risetime, when the shell thickness is big, the turning angle of torsion joint is small, but has high response speed, overshoot and low shock; when the rube average radius increases, the turning angle of torsion joint increases and the overshoot increases too; when the initial angle of torsion joint is big, the turning joint is big, the overshoot is small and shock is low, but the risetime is big; the connector's outlet area affects the dynamic process of FPA inside air pressure greatly, but has no effects on the dynamic process of turning angle; moment of inertia and viscous damping coefficient have no effects on the dynamic process of FPA inside air pressure, but affect the dynamic process of turning angle greatly.

在弯曲关节模型推导的基础上，建立扭转关节的静态模型，并分析了扭转关节内腔压力，初始转角，橡胶管平均半径，橡胶管壁厚等参数对关节转角的影响，得出扭转关节的转动角度与充入FPA内腔的压缩气体压力之间基本呈线性关系，扭转关节的转角随初始角度和橡胶管平均半径的增大而增大，扭转关节的转角随橡胶管壁厚的增大而减小的结论；建立了扭转关节的动力学方程，仿真实验表明FPA的充放气过程与扭转关节的动力学过程相比时间极短，在实际系统设计和控制过程中可以忽略不计；分析讨论橡胶管壁厚，平均半径，初始角度，气体节流口面积，转动惯量，粘性阻尼系数等因素对扭转关节动态特性的影响，得出橡胶管初始壁厚的变化对扭转关节FPA内腔压力的动态响应几乎没有影响而对关节转角的响应曲线影响比较明显，壁厚较小时，关节可以得到较大的转角，并且转角的响应曲线没有超调，但上升时间长，壁厚较大时，关节转角变小，响应加快，但是有超调和轻微振荡现象，橡胶管平均半径越大，得到的关节转角越大，但是转角响应的超调量也随之增大，FPA的初始角度越大，关节的转角越大，并且超调量减小，振荡减弱，但是上升时间增大，管接头出口面积的大小对关节FPA内腔压力的建立过程影响较大，但对关节转角的动态响应几乎没有影响，转动惯量和粘性阻尼系数对FPA内腔压力的动态过程几乎没有影响而对扭转关节转角有较大影响等结论。

According to the change of the enemy\'s quantity and the qualitative theory of the differential equation, we research the spruce aphides and its predator system. At the same time, we discussion the spruce aphid multiplication model when the natural enemy quantity is a certain value and the periodic oscillating model whose the quantity of the natural enemy changes along with the time. Obtains the stability condition of the balance point and the limit-cycle existing condition, the system presents the dissipative structure\'s character. Finally it explains that this theoretical analysis has certain practical significance regarding the preventing and controlling harmful insect.

第五章，松毛虫与其天敌的关系是食饵和捕食者的关系，根据天敌数量的变化，利用微分方程定性理论，研究松毛虫与天敌系统，讨论天敌数量为一定时的松毛虫增殖模型和天敌数量随时间变化的周期振荡模型，得到正平衡点全局稳定性和极限环的存在条件，通过计算机模拟，说明周期振荡的捕食模型能够呈现典型的时间耗散结构特征，对于防治害虫有一定的实际意义。

Cavity flows both with and without sound excitation are studied by solving the 2 D time dependent Reynolds averaged Navier Stokes equations using explicit predictor corrector difference algorithm of Mac Cormack.

采用显式MacCorma－ck二步预估校正有限差分格式，求解二维雷诺平均非定常Navier－Stokes方程；并用Cebeci－Smith代数紊流模型作适当修正来模拟紊流效应，对有、无前缘声激励两种情况的空腔流场作了数值模拟，计算的振荡频率及振荡幅值都与实验结果基本符合，并且较好地模拟出了声激励对流场的影响。

Fluid velocity and pressure oscillating equations are set up using finite element method.

应用有限元法，建立了粘性流体速度和压力振荡方程。

According to the nonlinear oscillation theory and the obtained equation, the nonlinear characteristics and evolution law of Kunming precipitation anomaly system were studied.

根据非线性振荡理论和昆明地区的非线性振荡方程研究了昆明地区降水距平率系统演变的非线性特征及其演变规律。

Applying convection equation describing local precipitation anomaly system and real-time meteorological observatory data, the nonlinear oscillation equation describing Kunming precipitation anomaly system was derived and retrieved.

从描述局地降水距平率系统的对流方程和实际气象观测资料出发，导出并反演了描述昆明局地降水距平率系统的非线性振荡方程。

On the basic of NNLSE and the Poisson equation, using the Green function approach, we obtain the response function of the lead glass of finite-size, which is a strong nonlocal medium. Starting with the paraxial ray equation, we obtain the analytical solutions of the oscillation trajectory and period of the beam.

基于非局域非线性薛定谔方程以及热传导的泊松方程，采用格林函数法求出了强非局域介质铅玻璃的响应函数和临界功率；从光线方程出发得到了偏离材料中心入射的光束中心振荡轨迹以及周期的解析解。

The oscillating behaviors in darkness of pyrogallic acid-KBrO-HSO-system have been studied, the relations between induction period τ as well as oscillating period and the initial concentrations of reactants of the system have been determined experimentally at 25℃、35℃.

研究了无光照条件下焦性没食子酸-KBrO-HSO体系振荡的基本规律，得到了25℃、35℃时起振时间τ、振荡周期T与各反应物起始浓度之间关系的经验方程。

One of the most important measures that are used to make TWT work stably and reliably is to suppress all kinds of self-oscillations, including BWO. On the basis of the coupled mode theory, considering the effects of attenuator/sever, taper/step phase velocity, voltage gradient of electron beam, etc.

本论文基于耦合模理论，全面地考虑了衰减器/切断、相速渐变/跳变和电子注的电位梯度等的影响，建立了抑制返波振荡的统一的自洽线性工作方程组，包括线路方程、运动方程和电流连续性方程，并给出了相应的边界条件。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。