近似计算

However, the calculation of the zero order correction of the DNLS/MNLS equation is intricate. We develope a symbolic computation technique to calculate them, based on the residue theorem.

但DNLS／MNLS孤子在微扰下的零级近似已经非常复杂，我们基于留数定理总结出一套有广泛适用范围的符号计算方法。

Results of analysis show that Generalized Paris Law can consider the complex crack propagation in the material of the pavement structure. The fatigue life of the pavement increases with increasing thickness of surface layer in a power function. Use of a thicker surface layer may extend the service life of the asphalt pavement. The fatigue life increases with decreasing modulus of surface layer in a power function with a negative exponent. However, since reduced modulus would scarify the structural strength and might cause rutting-related distress, caution should be taken when using low modulus materials for improving fatigue performance of asphalt pavements. The fatigue life increases with increasing modulus of base material in a power function. However, the fatigue life can not infinitely increases with increasing modulus of the base.

计算与分析表明：广义Paris公式可以考虑沥青路面结构内材料复杂的裂缝扩展：沥青面层的疲劳寿命随着面层厚度的增加以幂函数的形式增加，适当增加沥青面层厚度可以提高路面的使用寿命；沥青面层的疲劳寿命随着面层材料模量的降低以负指数的幂函数形式增加；由于材料模量的降低将牺牲路面的整体强度并可能引起路面车辙类损坏，以此提高疲劳寿命的方法应慎重对待；沥青面层的疲劳寿命随着基层材料模量的增加呈幂函数的形式增加，但由疲劳方程可以看出，寿命并不是随基层材料模量的增加而无限的增加，疲劳曲线在经过一个上升段后，逐渐趋于一个常数值，这说明，这时基层模量对寿命已不作关键性贡献；随着底基层厚度的增加，面层的疲劳寿命近似地呈线性函数增加，但效果并不很明显。

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。

Based on generator self excitation theory and the characteristics of black-start, we choose this simple method to be the criterion of generator self excitation problem in black start. Later, simulation of hydraulic generator self-excitation study is given.

从适用於黑启动快速这一特点出发，在已有的方法中选择了一种简单的近似方法来作为黑启动研究中自励磁产生与否的判据，从自励磁现象本质出发进行了阐述，并对水轮机组自励磁产生的暂态过程进行了仿真计算。

The design and make of a simple electric arc plasma generator;2. Mathematics expressions of arc curr en t are deduced considering the circuit resistance of the arc furnace,based on the assumption that electric arc voltage follows rectangle wave,and the elect ric parameters related to continuous and non-continuous electric arc are obta ined.

推导了在假定电弧电压为矩形波条件下，电弧电流的瞬时值数学表达式，明确了电弧连续性与随操作参数I/Is之间关系，推导中考虑了线路电阻的影响；分别求得了电弧连续与不连续情况下的无量纲电气参数；得到了电弧连续性准则；给出了计算临界功率因数的线性高精度近似计算式。

Theory analysis and the measured data are shown that excitation pulse in pile integrity testing is silimar to half-period of the sine curve, and different exciting methods produce signals with different period of time, so its frequency composition is also different.

理论计算及实测资料表明，反射波法基桩动测激振信号近似为半周期正弦波，不同激振方式产生的桩顶速度脉冲信号宽度不同，相应频率成分也就不同。

The major implementations of the developed model include: Pseudo-spectral and finite-difference schemes are employed to approximate the spatial-differential operators in the horizontal and vertical directions, respectively. A second-order Runge-Kutta method is adopted to integrate in time for the velocity field and the free-surface elevation. The solenoidal condition of the velocity field is satisfied by solving the transformed pressure Poisson equation. A modified secant method is used to accelerate the iterative solution of the non-separable Poisson equation.

模式的主要数值方法包括：分别以拟频谱法以及二阶有限差分法近似控制方程与边界条件中的水平与垂直导数；以二阶Runge-Kutta法进行非稳态的自由液面位移与流场速度的时间积分；利用改良式割线叠代法求解计算区间中不可分离的压力Poisson方程式，以满足不可压缩流条件。

For experimental setup to calibrate spectral radiance by applying a diffuse plane, the measured spectral radiance can be obtained through integral of spectral radiation flux entering the spectrometer.

在利用漫反射板标定光谱辐亮度的实验装置中，标准灯完全可以近似为点光源。通过对进入光谱仪的辐射通量的数值积分，可以对应求出仪器的实测光谱辐亮度的计算公式。

The application of high order spectral analysis is related to computations of high order moment functions and multi-dimensional Fourier transforms. The errors appear in these computations and limitation of measured data may cause the failure of such comparison.

高阶谱分析方法的应用中要涉及到高阶谱矩、高阶相关函数及高维傅立叶变换的计算，这些计算所带来的近似及试验记录的局限性很可能是导致两种方法比较时不成功的原因。

For the diffusion coefficients of electrolytes in aqueous solution by the mean spherical approximation was modified in two ways.

采用两种方法对Barnard等的用平均球近似理论计算电解质在水溶液中的扩散系数的方法进行了改进。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。