近似法

The NIEL induced by low energy proton in Si and GaAs have been calculated using analytical method and Monte-Carlo code. Thin_target approximation was used when calculating NIEL by SRIM code and the result compared with that of other authors'. The results show that thin_target approximation is reasonable and NIEL scaling is feasible. The NIEL values become lower after taking into account the screening effect.

为此，本文采用解析法和基于Monte-Carlo方法的SRIM程序计算了考虑库仑屏蔽效应后低能质子在半导体材料Si，GaAs中的NIEL，SRIM程序在计算过程中采用薄靶近似法，并与其他作者的计算数据和实验数据进行了比较。

This course provides a basic introduction of topics such as: interpolation, solution of nonlinear equations, curve fitting to measured data, numerical linear algebra, numerical integration, numerical differentiation, etc..

本课程介绍内容包括：内插法，非线性方程式求解，曲线近似法，线性代数数值运算，数值积分，数值微分等课题。

The Winklhofer method is an exact method.But Winklhofer method cannot calculate centerdistance of a roller chain drive whose length of chain is an odd number of chain pitches.Involute function method is anapproximative method.

W ink lhofer方法是准确的计算方法，但只能用于链条总长是链节的偶数倍时的链传动，而渐开线法是近似法，不能精确地计算链传动中心距；而二分法是一种数值法，它可精确地计算链传动中心距，并且适用于链条总长是任意值的链传动，可计算出链传动中心距最大值和最小值。

The two methods of model simplification are presented for large scale systems, they are the least square approximation and the rational fraction approximation.

本文针对大系统的频域模型简化提出了两种方法：最小二乘近似法和有理分式近似法。

The false scattering and ray effect in spherical harmonics method ,including P-1 and P-3 approximation,is studied.

从辐射传输方程的近似求解过程出发，在定性分析的基础上构造物理模型，通过数值模拟研究球谐函数法(P1和P3近似法)的假散射和射线效应。

Two different approaches, namely, the mode matching approach and the partial Fourier transformation of the Lippmann-Schwinger equation approach, have been employed to cross check our results.

我们使用了两种不同的方法、模态匹配近似法及Lippmann-Schwinger方程式的部分富立叶转换近似方法、来交互比对确定我们的结果。

In this paper, the experience method, gas phase pseudopressure method , B-W method, oil reservoir integration method and approximation method for analysing gas condensate well testing are emphatical- ly described, and their characters, correctness and application scope are also compared.

着重介绍经验修正法、气相拟压力法、B-W方法、油藏积分法和近似法等，并比较了它们各自的特点、正确性及适用范围。

Two examples are used to show that such perturbative method can be a useful way to obtain the approximate solutions of the Fokker-Planck equation.

我们发现，当外加力场具有某些时间的形式时，应用微扰近似法来解Fokker-Planck方程式可以得到精确解，同样地，我们也用两个例子来说明微扰近似法的实用性。

The equilibrium geometry,force constants and vibronic frequencies of the SiO2 molecule with linear structure have been optimized by using the Gaussian03 with B3P86/cc-PVTZ; The total internal partition sums were calculated for silicon dioxide with the product approximation. For rotational partition sums Qrot, the centrifugal distortion corrections are under consideration.

应用Gaussian03程序，在B3P86/cc-PVTZ水平上，对二氧化硅分子线性结构进行优化计算，得出其平衡几何构型、力常数和谐振频率等性质参数；采用乘积近似法构建模型计算了二氧化硅分子从20-6000K的总配分函数，其中转动配分函数考虑了离心扭曲修正，振动配分函数采用谐振子近似。

In this paper, firstly, the theory and the discretization schemes of LBIE and the concepts of MLS and GMLS are introduced; secondly, LBIE method is applied to solve the thin plate-bending problems and four typical examples are given to demonstrate the applicability and validity of the method. The results obtained from numerical examples agree well with the exact solutions and have an excellent rate of convergence.

本文首先介绍了无网格局部边界积分方程方法的理论基础和离散步骤，以及移动最小二乘近似法和广义移动最小二乘近似法等概念；其次将该方法初步应用于计算薄板的弯曲问题，建立了完整的积分公式，求解了四个典型算例，结果同精确解非常接近，且收敛快。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。