近似计算

According to Rayleigh-Jeans law,the emission of the object is directly linear to its absolute temperature.As the frequency of object increases,Rayleigh-Jeans Law deviates from Planck's Blackbody Radiation Law,and the radiation of object received should be calculated according to Planck's Blackbody Radiation Law.

由 Rayleigh-Jeans公式计算的物体的辐射功率与其物理温度成线性关系，但是随着物体频率的升高，Rayleigh-Jeans公式与Planck定律的近似误差越来越大，此时应根据Planck定律计算物体的辐射功率。

Aiming at the strong coupling characteristic during the multi-disciplinary optimization process of hypersonic aerocraft, in order to reduce computing time and increase the feasibility of optimization process, this paper adopted the approximate method to build the responding model between disciplines, In this paper, under the condition of ensuring the engine stable and high efficient , the designing work also consider the whole aerocraft performance sufficiently from the effect of forebody and afterbody.

针对高超音速飞行器多学科设计优化过程中的强耦合特性，为了减少计算时间，提高优化过程的可行性，采用近似的方法来建立学科之间的响应模型，以此来减少每次迭代时所用的大量计算时间。

Many methods on calculation of deflection of prestressed concrete beams have been proposed both at home and abroad, most of which were empirical formulas for approximate engineering calculation.

有关预应力混凝土梁的挠度计算，国内外学者提出了不少计算方法，但几乎都是以满足工程要求为前提的近似经验公式。

The approach to calculating the gliding angle and flight time of each segment was given.The procedure for approaching the whole glide trajectory was described.Two examples show that the differences in the gliding range and flight time between the approximate solution and the...

文中算例结果表明，该近似求解方法计算得到的滑翔航程和滑翔时间与实际值相差很小，航程误差率约为0.7%，时间误差率约为0.6%，因此该方法在近似小初始滑翔角的长航时远程纵向滑翔飞行时是有效的、可行的，尤其针对航程在地球半圈以上的滑翔飞行轨迹。

This paper applies simulation and actual data to make a comparative analysis of the effects of the four different references:average reference,linked mastoids reference,Cz reference and zero reference realized by the recently-developed REST(reference electrode standardization technique) for calculating the center of mass of EEG.

针对脑电头皮电位质心的计算问题，用仿真和实际数据计算比较了平均参考、连接耳参考、头顶参考和新近出现的近似零参考技术方法的差异，结果表明，采用REST可使得电位质心的计算误差在多数情况下更小。

For the application of Mathematica in the differential geometry,this paper introduces how to processe the curve curvature and the torsion questions,the graphic expression of the curvature and the torsions,and draw curves by the curvature and the torsions. Curvature ; torsion ; solution curve ; osculating plane ; natural parameter ; natural equation

利用Mathematica，只要输入有关系统命令就可以得到期望的结果。1曲率和挠率及其图形意义假设R3上的曲线一般参数表示为r=r它的曲率和挠率计算公式是：κ=‖r′×r&‖‖r′‖3τ=‖r′×r‖我们知道，空间曲线r=r在一点(s=s0)邻近的近似方程为ξ=sη=120κs2ζ=160κ0τs3通过近似方程可以确定曲线在其基本三棱形的三个平面(即密切平面，法平面，从切平面)上的投

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。

A simple radiation model was used to calculate daily changes of the aerosol radiative heating rates and cooling rates in different months. Two-stream approximation, hemispheric constant method, adding method and doubling method were applied in the computation.

摘 要：采用两流近似辐射模式，应用半球常数法近似，采用累加法和倍加法，计算了不同月份大气气溶胶的辐射加热率和减温率的日变化。

The main research tasks and results are as follows:(1) Through comparing the stress intensity factor of compact tension specimen calculated by finite element software with the theoretical value, the feasibility of calculating fracture parameters of crack tip in ABAQUS software was verified.(2) The relationship between the elastic modulus of the material and research scale was studied based on deriving the cohesive stress theory and other relevant theories. And the elastic modulus of the material on meso-scale was determined.(3) Global model and sub-model of the finite element were built in th...e macro-scale, and stress-strain field nearby the crack tip was analyzed, and the results show that the detailed stress-strain in the crack tip could be obtained by using the sub-model technique.(4) In meso-scale, the crack growth model was also established by assuming the crack propagating along the grain boundary, and the detailed stress-strain field in the crack tip was obtained.(5) The effect of crack length on Von Mises stress, and maximum principal stress and strain was analyzed in meso-scale when equivalent KI equals 30MPa.m1/2. And the results show that except for crack tip area, the stress-strain distribution in whole specimen is not affected.

主要完成研究内容和取得成果如下：(1)利用有限元软件计算出紧凑拉伸试样的裂纹尖端应力强度因子KI值，其结果与理论值一致，从而验证了利用ABAQUS计算裂纹尖端相关断裂参量的可行性；(2)在研究内聚应力等相关理论的基础上，推导出了研究尺度与材料弹性模量的近似关系，并确定了介观尺度上的弹性模量；(3)在宏观尺度上建立了全局有限元计算模型和子模型，得到了裂纹尖端应力应变场分布，结果表明利用子模型技术获得比较准确的裂纹尖端应力应变场分布是可行的；(4)在介观尺度上利用平均晶粒尺度的方式建立了裂纹沿晶扩展模型，得到了裂纹尖端断裂过程区的微观应力应变场；(5)当应力强度因子为30MPa.m1/2时，分析了介观尺度上在裂纹沿晶扩展过程中裂纹长度对Mises应力、最大主应力和应变的影响，结果表明，裂纹扩展长度对试样整体应力应变分布影响不大，而对裂纹尖端区域有较大影响；(6)介。。。

The correct coefficient of temperature difference can be taken as one, when this method is used to calculate the heat transfer coefficients of shield section.

结果表明，CRK法的计算误差小于传统计算方法，在进行遮蔽段传热计算时，错流温差校正系数可近似按l处理。

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。