数值稳定性

Routh-Hurwitz is used to determine that the characteristic equation has negative real root, and Center-Manifold theorem is used to study the stability of autonomous differential system in the case of hyperbolic and non-hyperbolic at the equilibrium point.

利用Routh-Hurwitz判定特征方程有负实部根，并利用中心流形定理研究了自治微分系统在平衡点处双曲和非双曲情况下的稳定性，由此产生系统趋于不同稳定点时病毒分裂的临界值，同时利用数值模拟验证了分析的合理性。

Numerical simulations of flow structure around a circular cylinder in oscillatory flow, ranging in Kc from 1 to 5 and β from 10 to 1665, are presented in the paper.

并与U型振荡水槽中的流场涡结构显示照片比较，计算结果表明，数值解在稳定性和收敛性方面都是比较好的。

The proposed method could not only efficiently tell between the inward and outward region of the closed curve or surface, but also solve the numerical stability problems of other methods. These superiorities have a significant impact in improving the computational efficiency and stability of level set methods.

所提出的算法能够区分任意形状的闭合曲线或曲面的内外部，改进了以往初始化算法的数值不稳定缺陷，从而使水平集方法的计算效率和稳定性有了显著的提高。

The mathematics function of determining the permeability has been derived and the permeability value of calculated from the function is comparable with others in molding sand standard.

对该方法的可靠性进行了实验验证，结果表明，该法所测数值对同一种涂料具有好的重现与稳定性；对涂料透气性的微小变化有好的敏感性；粘结剂量增加，涂料透气性下降。

Conditional stability.

反问题，边值问题，不适定问题，偏微分方程，积分方程，条件稳定性，数值分析

Experimental results show the recognition rate of the method is 95%for a known expresser and 72% for a novel expresser. Aiming at the shortcomings of optical flow technique,two improved optical flow algorithms are presented.One way is to introduce forward and backword constraint eqution and Hessian matrix of optical flow equation is computed.The well- posedness of each point of local neighbourhood is examined and the weight of Lucas-Kanade's method is defined as the reciprocal of the conditioning number of its Hessian Matrix.

3针对传统光流法的缺点，分别提出了两种不同的改进方法：其一为引入前向-后向光流方程，计算其Hessian矩阵，把Hessian矩阵条件数的倒数作为Lucas-Kanade光流法的加权阵，可有效消除局部邻域中不可靠约束点，同时提高基本约束方程解的稳定性；其二为针对传统光流法只适用于刚体运动的特点，在扩展约束光流方程的基础上引入了div-curl样条函数作为扩展光流约束方程的附加约束条件，给出了一阶和二阶div-curl样条约束下光流的数值解。

Numerical method is used to investigate the bogie's ateral stability under diverse nonlinear factors. The influence of nonlinearities and conicity on the critical speed is investigated. The nonlinear forces considered in the bogie system include creep-force between the rail and wheel, longitudinal damping and the flange contact force.

利用数值方法研究了不同非线性力作用下转向架的横向稳定性，得到轮轨饱和力、蠕滑力、纵、横向阻尼力、轮缘死区接触力、踏面斜率以及轮轨间隙对转向架系统线性、非线性临界速度的影响规律。

The numerical experiment results by researching the optimal problem of standard test functions show that the election-survey algorithm can constringe rapidly to global optimal solution and has better stability.

通过对标准测试函数优化的数值实验结果表明，竞选算法可快速搜索到函数的全局最优解，并具有较好的稳定性。

Based on the geometric nonlinear and material nonlinear of structure, the three dimension stability analysis of long span curve continuous rigid frame is performed on the base of the numerical analysis, and comparison of the linear and the non-linear is also done.

本文分别考虑结构的几何非线性和材料非线性力学特征，对高墩大跨弯连续刚构桥梁的结构稳定性进行详细的数值分析，并与线弹性的计算结果进行对比。

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

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。