数值稳定性

From finite difference equation of unsteady-state heat conduction ,according to vonNeumann method about scheme stability,the explicit scheme stability condition of two dimension computational heat conduction was given.

从非稳态导热的离散方程出发，根据VonNeumann的格式稳定性判别方法，给出二维导热数值计算显式格式的稳定性条件。

According to the Logistic Equation and the impact of stochastic factors, a stochastic nonlinear dynamical model had been presenred. The max Lyapunov exponent was calculated by Oseledec multiplicative ergodic theory, the local stability conditions had been obtained; the global stability conditions had also been obtained by judging the modality of the singular boundary; the stochastic Hopf bifurcation was analyzed using the invariant measure of stable probability density, and the condition of stochastic Hopf bifurcation had been discussed. The key parameter impacting the urban domestic water consumption had been found by numerical emulation.

根据Logistic阻滞增长模型原理，考虑到诸多随机因素的影响，本文建立了一个城市生活用水量的随机非线性模型，运用Oseledec乘性遍历定理计算了模型的最大Lyapunov指数，得到了局部稳定性的条件；通过对扩散边界性态的分析，得到了全局稳定性的条件；通过分析系统平稳状态概率密度的不变测度，得到了模型随机Hopf分岔的条件，结合实际进行了数值仿真，得到了影响用水量的关键参数。

With the knowledge of linear algebra, general formula for arbitrary order Taylor finite difference has been derived. In this paper, the analysis of spectral property and computational error of arbitrary order TFD is presented in detail. Then it is applied into the numerical solution of Maxwell's equations. Stability condition and numerical dispersion relation are derived.

本文借助于采样定理，详细分析了不同阶Taylor中心差分格式的谱特性以及计算误差，并将任意阶Taylor中心差分格式用于数值求解麦克斯韦方程中，严格导出了稳定性条件和数值色散关系的表达式，引入了新的误差定义来衡量算法的好坏。

Similarly, numerical experiments are performed to demonstrate the efficiency and efficacy of the geodesic distance based MFS for piecewise smooth domain. In addition, the effect of the number of collocation points and the stability with respect to the anisotropy are discussed.In Appendix A.

在后面同样给出了数值例子以说明方法的优越性，不同的是这里考察了分片光滑的几何区域，并加上了配置点数目对数值结果的影响以及该方法对各向异性的稳定性分析。

On the basis of least potential energy theory the stability and convergence are analyzed and discussed in Hilbert space, and the basic condition ensuring uniqueness and convergence of solution is given.

在Hilbert空间内，从最小势能原理出发对非协调数值流形方法的稳定性和收敛性进行了分析和讨论，得到了保证非协调流形元解唯一存在和收敛的基本条件，完善了非协调数值流形方法的理论基础。

In this chapter, a two-dimensional implicit difference scheme of the linear IBVP is designed, and the stability of the homogeneous scheme is proved by the method of separation of variable. At last, some numerical examples are presented. And the results are consistent with the theoretical result.

在本章中，建立了相应初边值问题的二维隐式格式，并利用分离变量法讨论了其中的一类特殊情形——齐次情形差分格式的稳定性，最后给出了数值算例，得到的数值结果与理论结果一致。

The stability of algorithm, the condition of absorbing boundary and free surface boundary, the grid dispersion and the process of source are discussed in details. The numerous simulations of wave propagation are carried out in isotropic media, transversely isotropic media and anisotropic media induced by fractures. The difference between anisotropic and isotropic effects on surface records is analysized.

接着讨论了有限差分算子的稳定性和收敛性，以及吸收边界条件、自由边界条件、数值频散和震源的处理，对各向同性介质、横向各向同性介质以及裂隙引起的各向异性介质中传播的弹性波场进行了数值模拟，分析了多波多分量数据中的各向异性效应以及各向同性在地表地震记录中的反映。

The critical value of Hopf bifurcation was calculated, and the stability of the limit cycle was discussed. The bifurcation diagram of the system was obtained by the fourth order Runge-Kutta method.

定性分析了系统定态的存在性和稳定性，讨论了系统的Hopf分岔，得到了系统的Hopf分岔参数值，并判断了极限环的稳定性。

And the convergence, compatibility and stability of the LLA based on the LTP are discussed with some theoretical analysis and numerical experiments, and the stability condition of the LLA is given.

对基于LTP的LLA方法的收敛性、相容性和稳定性进行了理论分析和数值实验，给出LLA的稳定性条件。

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。

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。