数值稳定性

To investigate the dynamic stability of a two-degree-of-freedom manipulator as a system,differential equations of motion for this system were established on the basis of the Lagrange equation,and perturbed differential equations with period coefficients were derived for the period motion of this system by applying the perturbance theory.

为了研究两自由度机械手系统的动力学稳定性，基于拉格朗日方程给出了它的运动微分方程，并用扰动理论确定系统周期运动具有周期系数的扰动微分方程；根据F loquet理论对该系统扰动微分方程的平衡点的稳定性进行了分析，并用数值方法研究了平衡点失稳后的倍周期分岔过程。

The calculation results shows that ,(1) when the rotor rotates at the working speed, a local regurgitant whirlpool that is rightabout to the rotor"s rotating direction appears in the classifying region, which makes the separated granules come back to the outside of the classification district and influences the classification efficiency of the turbine classifier;(2) in the condition of a low rotating speed of turbo rotor, ultrafine particles can follow the gas phase by and large, but when the rotating speed increases, a phenomenon of velocity slippage between two phases appears evidently;(3) A operating parameter, air flow rate is so important that can directly influence the stability of flow field in classifying chamber, the bigger the air flowrate is , the steadier the flow field is;(4) Compared with straight blades, the new shape of blades with backward crooked elbow are helpful to improve the stability of flow field and form whole stream easily, also beneficial to advance the classification accuracy and classification efficiency;(5) The motion trace of particles are very complicated when the turbo rotor rotates at a high speed, the constant bounce of the particles appear between the blades and the coarse particles are even bounce back from the inlet, only the finer can pass through the classification area from the oulet;(6) Along with the increase of the rotor"s rotating speed, radiah axial and tangential velocity all begain to fluctuate repetitively like sine-wave, the smaller the particles are, the more violently they fluctuates.

数值模拟结果表明，(1)在涡轮达到工作转速时，在分级区域形成了一个与涡轮旋转方向相反的局部回流涡，它使得分离出来的细粒重又被带回分级轮外边缘，从而严重影响分级机的分级效率；(2)粉尘粒子在涡轮低速运动情况下，基本上能跟随气体运动，但随着转速加大，两相之间出现了明显的速度滑移现象；(3)分级机工作时的风量也是一个比较重要的操作参数，它可以直接影响到分级机内腔流场的稳定性，风量越大，流场越稳定；(4)同直叶片形状相比较，带后弯导板的叶片，有利于改善流场的稳定性，流场容易形成整体流，对提高分级效率和分级精度都非常有利；(5)粒子轨迹线在涡轮转速较高时十分复杂，有的出现了反复的弹跳现象，大颗粒不能通过分级区域而从进口返流了，只有细小的颗粒才从出口处流出；(6)涡轮转速加大时，粒子的径向、轴向和切向速率出现了明显的类似于正弦波的脉动现象，颗粒越小，脉动程度越为剧烈。

The reconstruction problem is ill-posed, so two optimal criterions, the least module and the smoothness criterion base on Tikhonov regularization technique, are introduced into reconstruction algorithm. Many regularization parameters choice strategies are investigated, and the TPA(Two—Parameter Algorithm) strategy which is based on the Morozov discrepancy principles, is implemented in two regularization reconstruction algorithms.Numerical experiment results show that the nonnegative and smoothness constraint condition can overcome the difficulty of iteration semiconvergent, preconditioned technique can improve convergence rate and reconstruction accuracy, smoothness regularization criterion can meliorate ill-posed problem of reconstruction and enhance iteration stability, and the TPA is an effective strategy of regularization parameters choice.

数值试验表明：在共轭梯度法中引入非负约束和光滑约束改善了迭代的&半收敛&性，非负约束保证了解的非负性，光滑约束抑制了重建解的振荡现象，约束算法的重建精度与无约束算法相比大幅度提高；在约束共轭梯度重建算法中引入预优技术，可以加快算法的收敛速度，提高迭代的稳定性和重建精度；引入光滑准则的正则化技术可以有效改善图像重建问题的不适定性，加快迭代的收敛速度，提高迭代的稳定性和图像重建质量，计算正则参数的TPA算法在闪光照相图像重建中是有效的。

By adopting the calculating analysis method of elastic-plastic three-dimensional FEM numeric simulation, this paper makes a simulation analysis on the structure stability of the shallow cover and unsymmetrically loaded parts in Tongyoushan tunnel, mainly simulates the effects caused by different construction orders on surroundings and supporting structure stability, and it centers on the analysis on the weak part, the midwall in the lining of the connecting-arch tunnel.

采用弹塑性三维有限元数值模拟计算分析的方法，对桐油山隧道浅埋、偏压地段结构稳定性进行了模拟分析，主要模拟了不同施工顺序对围岩及支护结构稳定性的影响，重点对连拱隧道整体衬砌中的薄弱环节－中墙进行了分析。

It is shown that the direction of bifurcation and the stability of the bifurcating periodic solutions of the Euler methods are the same as the direction of bifurcation and the stability of the bifurcating periodic solutions of the original delay differential equation when the stepsize is small enough.

证明当步长充分小时数值Hopf分支的分支方向、分支周期解的稳定性与原方程的Hopf分支的分支方向、分支周期解的稳定性相同。

The characteristics of Hopf bifurcation from the origin, including the existence condition, the direction as well as the stability of bifurcating periodic solutions are discussed in detail, which can be demonstrated by the numerical simulations.

讨论了快慢两时间尺度下超混沌Lorenz系统原点的稳定性问题，分析了原点的Hopf分岔，包括Hopf分岔的存在性，分岔方向以及分岔周期解的稳定性等问题，并用数值例子对所得到的结果加以验证。

It is not enough to resolve all of the problems related to the hydraulic stability only to analyze the stable field in passing components. Finally, the paper numerically simulated the transient field in prototype's draft tube under different operating conditions by means of Reynolds stress turbulence model and analyzed the law of motion of vortex rope as well as the performance of low-frequency pressure pulsation and compared with field test results.

仅仅对机组的过流部件进行稳定场的CFD数值分析还不足以解决所有与水轮机水力稳定性有关的问题，因此在本论文的最后，采用雷诺应力湍流模型对真机尾水管在不同运行工况下进行了非稳定场的CFD数值解析，分析涡带的运动规律及其产生的低频压力脉动特性，并与真机的试验结果进行了比较，结果比较吻合。

To know the stability of the bridge foundation in the course of construction and running, this paper sums up the numerical methods and monitoring artifices with which to analyze the stability of foundation.

为了掌握大型桥梁地基基础在施工期与运营期的稳定性，本文研究了稳定性分析的主要数值方法和监测手段。

Firstly, based on the sliding mode control and backstepping technique, a new attitude tracking controller is derived to control the attitude motion of spacecraft, the stability of the system is analyzed via Lyapunov method and the reaction wheel dynamics is also considered from the real applications point of view. The whole design process is divided into two steps: the first step is to use sliding control technique to design suppositional adaptive variable structure controller; and the second step is to design attitude tracking controller based on SMC and backstepping technique. Numerical simulations are performed to show that both tracking maneuver and vibration suppression can be accomplished effectively.

首先，采用自适应后步法结合主动振动控制技术设计了姿态跟踪鲁棒控制器，基于Lyapunov方法分析了系统的渐近稳定性；在此基础上，显性地考虑了执行机构动态特性问题，将整个设计过程分为两个步骤：第一步采用滑模控制技术设计了变结构虚拟控制器，给出自适应控制律的设计方法；第二步，将后步法与滑模控制技术相结合，设计了姿态跟踪鲁棒控制器，给出飞轮电压的输入算法及稳定性分析；最后，将提出的控制方法应用于挠性航天器的姿态跟踪控制，通过数值仿真对所提方法的可行性与有效性进行分析和验证。

Then confirm the validity of the controller through simulation algorithm.Here we realized the stable control of chaos system through the mutual effect of state variable which is extremely simple and easy to realize.

本文结合反馈控制方法，提出了一种基于系统状态变量的错位线性控制器设计策略，用李雅普诺夫稳定性方法证明了该控制策略的稳定性，并设计了数值仿真算法验证了控制器的有效性。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。