近似法

Its improved form of three terms series including Rubin second-order approximate terms and their exact residual term is then obtained.

采用叠加法和删除保留模态法导出了自由界面精确剩余模态三项和公式，它在Rubin二级近似项上增加了精确余项，导出非线性精确综合方程，构造了具有超收敛性质的迭代求解方程。

We present quantum mechanical vibrational computations beyond the harmonic approximation from effective second order perturbative and variation perturbation treatments defined as static approaches, as well as vibrational analysis from density functional theory molecular dynamics trajectories at 300 and 600 K.

利用超简谐振动近似的有效二阶微扰法(VPT2)和变异微扰法两种静态方法，以及在300和600K下的密度泛函分子动态轨线振动分析方法进行量子力学的振动计算。

Therefore, basic methodologies for stochastic seismic and filtering responses of nonlinear structure are studied, the approximate solution methodologies and their practical applications are investigated in the dissertation employing equivalent linearization and moment equations method based on FPK equations and Ito stochastic differential equations. The research works are mainly concerned with the following aspects:Firstly, the differential expression of bilinear hysteretic is studied and a new differential expression is developed, then they are demonstrated.

因此，本文基于FPK方程和伊藤随机微分方程，研究了滞后结构物的随机地震反应和随机滤波问题的基本方法，并利用等效线性化法和矩方程法，研究了非线性结构随机地震反应分析和随机滤波分析的近似解法及它们的工程应用。

By introducing the nonlinear complementarity problem function, the Karush-Kuhn-Tucker conditions of OPF model are transformed equivalently into a set of semismooth nonlinear algebraic equations. Then the set of semismooth equations can be solved by a semismooth L-M method based on the subdifferential. The method belongs to Newton-type method. It can ensure the positive defmitiveness of the iterative coefficient matrix by using the L-M parameter, which avoids the ill-conditioning of iterative equations. The method, requiring only the approximate solution of a linear system at each iteration, is quite applicable to the large-scale cases.

在利用非线性互补函数将OPF模型的KKT条件转化为半光滑非线性代数方程组后，采用基于次微分的半光滑L-M法求解，该方法属于牛顿法范畴，可通过对L-M参数的调整保证迭代系数矩阵的正定性，克服了系数矩阵的奇异引起的"病态"，且该方法在确定搜索方向时只需求解线性系统的加热器近似解，适用于大规模系统的求解。

An engineering approximately design method-equivlent circuit isalso introduced by equilent circuit of waveguide ET-junction and principle of symmetry and of multiplication of matrix.

本文同时依据对称性原理、ET接头的等效电路及传递矩阵的乘积原理建立了波导谐波滤波器的近似工程设计方法——等效电路法，指出等效电路法虽然精度有限、但计算时间很快，可以进行基、谐波全频段分析。

Besides,the trapezoidal method and parabolic method is used to make approximate calcalation and error estimate of the integral.

同时 ，用梯形法和抛物线法对此积分作了近似计算和误差估

In order to make the new recursive method convergence fast, the RLS-like forgetting factor is introduced to construct the new data Hankel matrices. In the framework of subspace methods, the gradient type subspace tracking method is used to implement the update of the state subspace, which results the unbiased estimate. Different from traditional offline method, the system matrices are recursively computed using RLS method. The convergence analysis of the proposed method is given and finally, the efficiency of this method is illustrated with a simulation example.A new closed-loop identification method is proposed to implement consistency estimation of closed-loop subspace identification.

引入RLS-like遗忘因子机制构造新的数据矩阵，更好地跟踪系统时变信息，提高递推算法的收敛速度；在子空间辨识框架内，采用梯度型子空间跟踪算法实现对状态子空间的更新，避免了子空间近似带来的估计有偏性；与传统的离线算法不同，在得到系统状态子空间后，基于递推最小二乘方法提出新的算法，实现对系统矩阵的递推估计；并给出递推子空间辨识算法的收敛性分析；最后通过仿真实例验证算法的有效性。

Through such a study, it is also shown that when the time delay is long enough such that the stability switches of the equilibrium of system halt, the bifurcation branches originated from the critical time delays cannot be surely stable or unstable in the whole solution space, that is, their stability depends on cases.

利用打靶法的数值结果说明了当系统平衡点不再发生稳定性切换时，源自这些临界时滞处的解支的稳定性在整个解空间的稳定性具有不可判定性，这也说明由多尺度法所得高阶近似判定的解支的稳定性事实上只表示解支在局部中心流形上的稳定性，而非在整个解空间中的稳定性。

After a detailed discussion of the variation theorem for upper bound calculation of eigenvalues, many standard procedures for determining lower bounds to eigenvalues are presented with chemical applications in mind.

本文将介绍无元素葛勒金法，此无元素法为利用变动最小二乘法所求的近似函数引入葛勒金弱式推导。可克服有限元素在工程上的限制。

Vibrio parahaemolyticus 1211U was cultured in sterilized sea water by the process of filtration at 4 ℃;50-60 days later, plate count and most probable number showed that there were no culturable bacteria.

将副溶血弧菌菌株1211U培养于低温贫养条件下，以平板菌落计数法和最大近似数法检测可培养细菌数，50～60d后表明可培养数下降为零。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了