近似公式

In this paper, the following progress has been discussed:(1) the improved conjugate gradient algorithm which combines the inversion equation;(2) the formulation for velvet gene at all directions and the approximation method of Jacobian matrics based on disturbance method;(3) the model is adjusted by analyzing the influence of damp coefficient and correction factor to inversion result ;(4) the influence of damp coefficient to the resolution of inversion is studied. to some degree, we improved the problem of "barycenter ascending shift" to electric anomalous body in 3-D resistivity inversion.

本文主要讨论了以下几个方面的内容：（1）结合反演方程式改进的共轭梯度算法；（2）基于扰动法的线源Jacobi矩阵的近似计算方法及光滑系数矩阵在各个方向上的光滑因子的计算公式；（3）通过分析阻尼系数与修改量校正量对反演结果的影响，提出了利用校正系数对模型修正量进行校正；（4）较为系统的讨论了阻尼系数λ对反演分辨能力的影响，较好的改善了三维电阻率反演中的电性异常体重心的&上漂&现象。

In this paper, a reconstruction algorithm of acoustical tomography is presented for absorbing scatterers based on the second-order Rytov transform perturbation approximation.

文中详细讨论了Rytov二阶近似下的声逆散射微扰论公式，并考察了它的适用范围。

Based on pole model of lathe, thickness of side-board is treated as design parameter. This problem becomes a nonlinear problem, but it may become a linear problem using method of differential coefficient. Through method of calculating energy of sub-structure, thinking of each board separately, so getting final results rapidly.

以机床立柱模型为例，将模型的侧板板厚作为设计参数，并运用微分近似的方法，将非线性问题简化为线性问题求解，推导出了适用于板结构设计的计算公式，并通过计算子结构能量的方法，将每块侧板分开来考虑，降低了对计算机处理能力的要求，从而快速得到最终结果。

In this paper we present the results of a theoretical study of the focusingproperties of a symmetrical two-cylinder lens with identical radii and negligibleseparation for relativistic electron beams.

本文提出相对论情况下双圆筒静电透镜的聚焦性质，得出在薄透镜近似下的解析公式，并给出计算实例及与数值积分计算相比较。

According to the post-tensioning method in prestressed concrete members,the calculation method of prestress losses caused by the deformation anchorage device,slip of tendon and joint compression was big in the error and narrow in the scope of application.

针对后张法预应力混凝土构件中由锚具变形、预应力钢束回缩和接缝压缩等引起的预应力损失计算方法适用范围较窄和误差较大的缺点，基于变形协调条件，通过分段近似计算方法，建立了锚具变形、预应力钢束回缩和接缝压缩等引起的预应力损失计算公式，并与实际预应力混凝土T形截面简支梁的计算结果进行了比较。

Under spraying humidification state, the parameters of JYPW-1 spraying axial fans for textile enterprises such as flow, total pressure, efficiency, shaft power and acoustic power level changing with water-air ratio were tested, and the performance parameter curve changing with water-air ratio was obtained. The approximate formula of its pneumatic performance in different water-air ratio condition were deduced which can be referenced for of selection and project application.

在喷雾加湿工况下，对纺织空调系统所用的JYPW-1型喷雾轴流通风机的流量、全压、全压效率、轴功率和比A声级噪声等性能参数随喷淋水气比的变化进行了测试，得到了喷雾风机性能参数随水气比变化的曲线，并整理出喷雾风机在不同水气比时，其气动性能的近似计算公式，可供喷雾风机选型和工程应用时参考。

The VCL method and the displacement method are used to calculate the Stress Intensity Factors of semi-elliptical surface crack at the root of pipe screws, on the basis of which a simplified calculating model for screws contact is put forward so as to analyse the fracture intensity for oil drill pipe screw coupling. For the semi-elliptical surface crack with different shape and deep ratio at the root of female and male screws and the corner of male flange, the SIF has been studied systemically under inter-pressure, tension, bend and torsion loads and the approximate formulas encluding the structure parameters of oil drill pipe screw coupling, deep ratio and the shape parameters of surface crack are developed.

对工程实际中的多种石油钻杆接头螺纹连接件，就公螺纹齿根、母螺纹齿根、公螺纹台阶转角处存在的不同形状、不同厚度比的半椭圆表面裂纹，在拉伸、内压、弯曲、扭转多种载荷作用下的应力强度因子作了系统研究，在大量有限元计算基础上，建立了包含接头结构参数、裂纹形状、厚度比在内的近似计算公式。

The corrections of the first excitation state fur plane rotor in external electrical fieldare discussed by means of the second order corrections formulation that is presented when degeneracy is never removed under the condition of the first approximaton.

利用一级近似下简并完全没有消除情形下的二级修正公式，讨论了平面转子在外电场中第一激发态修正。

In the linear analysis, with the aid of the theory of random vibration, the formula for the deflections and the acceleration are carefully deduced, and a simple method is given.

本文的分析包括线性分析和非线性分析，在线性分析中，利用随机振动的基本理论，推导了结构位移响应和加速度响应的计算公式，并给出了响应的近似计算方法。

According to density of particle numbers and energy of perfect quantum gas ,by strict theoretical calculation ,the energy of non relativity and relativity about perfect quantum gas under high temperature and low density is given.

根据理想量子气体的粒子数和能量的密度，通过严格的理论推算，给出理想量子气体在高温低密度条件下非相对论和极端相对论能量；再由巨正则系综中能量和压强相对涨落的公式，采用合理的近似方法，给出巨正则系综能量和压强相对涨落的严格解，并将其与正则系综对比，完备地展示两种系综在强度量的涨落方面热力学的等价性和个性差

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。