近似法

A current based hybrid method combining the MOM with the Kirchhoff approximation for analysis of scattering interaction between a two-dimensional infinitely long conducting target with arbitrary cross section and a 1-D rough sea surface with PM spectrum is proposed.

利用基于电流计算的矩量法结合高频算法基尔霍夫近似的混合算法，分析了一维PM谱粗糙海面及其上方二维无限长任意截面导体目标的双站复合电磁散射特性。

Put the discrete algebraic equations of initial derivative conditions and algebraic equation system of governing differential equation together to form a new algebraic system.

采用重心Lagrange插值近似未知函数，推导了未知函数各阶导数微分矩阵的显式表达式，建立了求解二阶常微分方程初值问题的重心Lagrange插值配点法。

The alternating group iterative method for the dispersive equation with periodic boundary condition is presented.

给出了求解具有周期边界条件色散方程近似解的交替分组迭代法。

Based on the relevant movement between hard shaper cutter and grinding wheel, the movements of grinding wheel are studied. The shaping grinding point and the shaping grinding edge are made up with. In order to easily compare when shaping errors and cutting edge"s angles are the most excellent, uniform expressions for convex curved rake face of hard shaping cutter and spatial cutting edge curve are separately developed. The distributions of new profiling cutter"s shaping errors and cutting edges angles are analyzed. The relevant grinding wheel and cam are designed. Due to this paper, a new profiling hard shaping cutter has been manufactured successfully. At last experiments are made to test the performance of hard shaping cutter and all kinds of precision of hard gear.

本文直接从插齿刀与砂轮之间的相对运动关系出发，单独研究砂轮的运动，提出砂轮成形磨削点和砂轮成形磨削刃的概念；分别建立圆柱砂轮和圆锥砂轮磨削后硬齿面插齿刀的波形前刀面方程及空间切削刃方程；为便于比较何种情况下插齿刀的构形误差和切削角度能同时达到最优，分别对磨削五种不同硬齿面插齿刀所用的砂轮进行了廓形设计，并分析了插齿刀的构形误差和侧切削刃切削角度的分布规律；为插齿刀波形前刀面的磨削加工设计了相应的凸轮，用所设计的凸轮和近似的砂轮成功地制造出新构形法硬齿面插齿刀；最后进行插齿加工试验，检验新构形法硬齿面插齿刀的抗崩刃能力、耐磨性及被加工硬齿面齿轮的各项精度。

This paper presents two methods to estimate the relationship between dent depth and contact force, respectivelyβamend method and deflection compensate method, which are developed by using a clear geometrical relation to express indent, incursion profile and deflection difference.

本文以一种新的观点，用一个明确的几何关系来确定压痕、压头与板的接触面剖面及接触中心点与边界点之间的挠度差三者之间的关系，提出两种近似预测接触力与压痕深度关系的方法——β修正法和挠度补偿法。

The probability distribution model is often used in simulation system to get the needed random number. Firstly how to simulate approximately the common method of probability distribution with Monte-Carlo is presented, and a high quality number randomizer is designed. The frequent stochastic distribution models on simulation system are mainly examined, which have some worth in utility.

计算机仿真系统中经常要应用研究对象的随机分布模型获得符合要求的随机数，给出了利用蒙特卡罗法来近似地描述研究对象的概率分布的一般方法，设计了高质量的随机数发生器，研究了利用MC法得到计算机仿真系统中常见的随机分布模型算法，具有一定的实用价值。

The granular discrete element method can be applied to the partials, whose shape can be approximately described as a sphere.

离散元法是分析散体力学行为的数值方法，颗粒离散元法适用于单个几何形状可用圆球近似而不产生显著差异的情况。

This paper applies approximate equation to describe the characteristic curve of an axial flow fan, for the purpose of determining its working system,and is intended to apply the equation method for enlarging the extent of the analy-tical method, commonly used for determining the working system of axial flow fan and the ventilating syetem of a mine.

本文应用近似方程来描叙轴流式扇风机的特性曲线，其目的要确定矿井轴流式扇风机的工作制度，并且企图使扇风机工作制度与矿井通风制度上应用方程法来扩大分析法的范围。

The Eddington scheme is slightly more accurate in thicker optical depth region, while the two-stream DISORT is more accurate in the thin optical depth region where the solar zenith angle is less than 60 degree. Second, we compare the two two-stream schemes in a realistic atmospheric profile with gaseous transmission considered.

对于单层大气，Eddington 近似在光学厚度大的时候比二流离散纵标法更精确一点；而二流离散纵标法在光学厚度小且太阳天顶角小于60 度的时候更准确。

Nonlinear partial differential dynamic equations of bending vibration of a tilting stepped drive shaft with two supports were built under non-inertia movement coordinate system by theorem of the motion of mass center and Heaviside function. According to the condition of equal displacement in an adjoining plane of the shaft, an equivalent shaft and its equation were obtained. A motion equation of the equivalent shaft was obtained by method of Galerkin. An approximate steady-state solution of the main resonance was obtained by method of multiple scales. The influence factors, motion stability, amplitude jump of main resonance of a stepped drive shaft and so on were analyzed.

用质心运动定理、Heaviside函数建立了非惯性系下倾料两端支承阶梯传动轴的非线性弯曲振动偏微分动力学方程，并根据相邻轴段的衔接面处位移相等的条件，得到阶梯轴的当量轴及其动力学方程；用Galerkin法得到当量轴的弯曲运动方程，用多尺度法求得稳态下当量轴的主共振的一次近似定常解，分析了影响阶梯传动轴主共振的因素、运动稳定性、振幅突变性等。

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。