近似计算

For a general parametric curve/surface, we usually cannot compute its exact implicit form. Even though its exact implicit form can be computed, the curve/surface implicitization involves relatively complicated computation and the degree is higher. Moreover, it may have unexpected components and self-intersections. All these unsatisfied properties limit the applications of the exact implicitization. So finding curve/surface approximate implicitization has become a practical problem. In this paper, we present an algorithm to solve the approximate implicitization of a given parametric curve by using a quadratic algebraic spline curve.

由于精确隐式化过程不一定可以实现，即使可以实现隐式曲线曲面的阶数高计算复杂，并且具有不希望的自交点和奇异分支，从而限制了隐式化的运用，所以寻求参数曲线曲面的近似隐式化问题成为很实际又重要的问题，提出利用二次代数样条曲线来实现一般平面参数曲线近似隐式化的一种算法。

To resolve thismodel,one approximate liner first derivative equation is used.An simple caculatemodel is setted up for caculating the motive adjust,and a mathematical equation incaculating the range of pressure motion in the system.Experiment data showe thatthese models have high accurecy.

在此基础上，对分析模型采用一阶微分近似线性化处理，建立了计算动态调节过程的简化计算模型，并以此建立了计算系统压力动态变幅的计算式，试验表明简化模型具有较高的精度。

Combining the definition of CWT and the derivative property of convolution, we constructed a general method to calculate the approximate derivative of signal through CWT by using the first and second derivative of Gaussian function, Haar, and the first derivative of three-order-Spline function as wavelets. As compared with the other approaches of calculating derivative, which include the numerical differentiation, polynomial filters, Fourier transform, and the recently proposed DWT method, fast calculation and simple mathematical operation were remarkable advantages of CWT method. For the signal corrupted by severe noise (Signal-toNoise Ratio=5), the satisfactory results could also obtained via CWT method through appropriately adiusting the dilations.

在此基础上，(1)结合连续小波变换的特点和卷积的微分性质，提出了使用Gaussian函数的一阶和二阶导数，Haar和三次样条函数的一阶导数作为小波函数的连续小波变换计算信号近似导数的一般性方法，与其他导数计算方法(包括数字微分法，多项式滤波法，Fourier变换法和离散小波变换法)相比，本法简单便捷，计算速度快，对于噪声含量较高的信号(S/N为5)，只要适当调节尺度即可获得比较满意的结果。

Bsed on real circumstances of TV transmitting station,the artiele presents a methodof calculation of field strength in case the radiowave is affected by ground objectsand meteorological conditions,and that of approximate calculation of field strengthIn penumbra areas,and so on,A method of calculating field strength in city is alsopresented with int...

文章从电视发射台的实际情况出发，介绍了电波受地物、气象等影响时的场强计算方法和半阴影区的近似场强计算方法等。还介绍了在城市的电波计算中，引入"建筑物密集度"参数的场强计算方法。

At the end of this chapter a concrete calculation example of Gauge transformation is given.In chapter 2 of this paper, two example applying gauge transformation for Quantum Geometric Phase in adiabatic condition are given, with explicit calculation process .The two examples is similar in objects to calculate, they are two state quantum system expressed in sphere coordination.

第二章主要讲了两个利用含时规范变换求解绝热近似下的几何相的例子，给出比较具体的计算步骤，它们有一个共同特点就是计算的对象都是二态体系，计算时采用的都是球坐标系，计算的都是只有两个量子态的纯粹的量子系统。

Main contents and conclusions are: 1 The ionization current was measured continuously by a charge-integration method with a computer after the introduction of radon into the chamber.

主要内容及结论：1充氡后利用计算机连续进行电离电流累积测量，得到了精细的电流随时间的变化曲线，可清楚看出氡及其子体的生成衰变造成的电离电流的生长—稳定—衰减过程，与理论计算值进行了比较，由电离电流衰减速度的变化得出氡吸附作用的影响，并测量到电离室冲洗后氡的反扩散现象；2由已知活度的标准源定出相对测量的刻度系数K值，K=24.62 Bq／pA，对同一个监测源以半年为周期进行多次测量后得出稳定性符合要求；3通过测量电离电流和气压的关系曲线以及不同气压下的饱和曲线，确定了常规的工作条件；4测量了盐酸清洗电离室内表面降低本底的效果；5不确定度分析表明相对测氡的扩展不确定度(k=2)小于5％，由本底涨落得出探测下限为0.5 Bq；6理论上对壁损失修正进行了计算，实验上保持电离室工作在饱和区的情况下，测量了不同气压下电离电流的变化，从中得出了壁损失随气压变化的规律，可以看出，电离电流的实测值和计算值随气压变化规律基本一致；当气压大于125 kPa时，端效应等其它因素造成的影响不大于2％，因而在此工作条件下，测量电离电流后通过计算修正壁损失可以实现近似的绝对测氡，提出了进一步提高绝对测量准确度的方法。

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 energy levels of free metallic ion were calculated with a 13 parameters model including the 2-body and 3-body interactions. The Stark energy levels of crystal field were calculated using the model proposed by Newman based on 1 electron orbital approximation The f-f oscillator strength calculation includes the contribution of electrostatic-induced, ligand polarization, vibronic-induced, magnetic dipolar transitions.

其中，自由f离子能级计算采用包括双电子与叁电子组态相互作用的二三参数模型，晶体场Stark分裂计算采用单电子轨道近似，用Newman角叠加模型计算晶体场参数。f-f跃迁振子强度计算包括静电诱导偶极跃、配体极化偶极跃、振动诱导电偶极跃迁及磁偶极跃迁的贡献。

Rolling force and moment are the basic technics parameter for Assel rolling mill design,but about it,s technics calculate is very poor currently.one form by dint of approximately calculate, the result unlikelihood .J·kazanecki and domestic scholar according as metal distortion superior limit,gave some formula have some worthiness,but very complexity.the author base on practicality rolling technics, gvie a simpleness calculate means.the result close to measure numerical value,supply some reference value.

轧制力、轧制力矩是设计Assel轧管机最为基本的参数，但是目前关于其工艺计算的理论还很不成熟，只能借助于近似工程计算方法求得，结果往往偏差较大。德国的J·kazanecki和国内的一些学者提出了利用金属塑性变形场的上界法求解上述参数，具有一定的参考价值，但其数学计算相当繁杂。作者从轧制工艺实际出发，遵循塑性力学的基本原理，给出了简便易行的计算方法，具有重要的实际意义。

Phase-lagged cyclic boundary condition is implemented by a novel method in conjunction with the developed sliding interface technique to accurately simulate the arbitrary pitch ratio rotor/stator interaction without any modifications of the physics of the problem. It's for the first time to compose the computational area into one structured grids including both rotor/stator of centrifugal or axial turbomachinery with arbitrary pitch ratio. This method can eliminate the iteration of boundary conditions on the sliding interface and calculate the unsteady flow within rotor and stator simultaneously.

为了能够在较小的计算区域内不改变叶型而真实地反映出任意栅距比时的内部非定常流场，并避免近似仍采用相位后滞周期性条件，结合本文发展的网格技术，给出了一种新的实施方法，首次将动、静叶片数不等的离心式/轴流式叶轮机械转子、静子计算区域组合在一套结构化计算网格中，动/静叶排间的滑移界面完全按内场处理，避免了每一时层内，滑移界面处边界条件的迭代计算；并保证了每一时层，滑移界面处流动参数的守恒特性。

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。