查询词典 approximation method

Fourier transform method can be directly derived from symbol function＇s separable approximation.

Fourier变换方法则直接用象征函数的可分表示求出。

The boundary value problem for first-order differential equations with a parameter refers to the finite solution condition of equation which includes unknown quantity and its first-order derivative that not only relies on interval value but also relies on the parameter of the equation,which is always settled by fixed point theory or successive approximation method.

含一个参数的一阶微分方程边值问题是指：含有未知量及它的一阶导数的方程的定解条件不仅依赖于在区间端点的取值，而且依赖于方程中的参数。通常它用不动点定理或逐步逼近法来解决。

In this paper, the theoretical model of CQI is described in an atom-diatom system in the condition of the molecular beam, based on the first-Born approximation of time dependent perturbation theory, taking into accounts the anisotropic Lennard-Jones interaction potentials. The method of observing and measuring correctly the differential interference angle is presented. The relation between differential and parameter, velocity is obtained. The relation of the integral interference angle and temperature is discussed.

文中利用一阶含时波恩近似和L-J相互作用势，建立了原子-双原子分子碰撞系统转动传能的量子干涉模型，描述了观察和测量微分干涉角的方法，得到了微分干涉角与碰撞半径和碰撞速度间的关系，同时也得到了积分干涉角和实验温度的关系。

The differential and partial wave scattering cross sections of Ne-H2(D2,T2) collisions have been calculated by close-coupling approximation method using Tang-Toennies potential model at the incident energy of 83.8 meV.

使用密耦近似（Close-Coupling）方法、采用Tang-Toennies势模型计算了惰性气体原子Ne与H2分子及同位素D2分子在碰撞能量为83.8 meV时的微分散射截面及分波截面，并与实验值和文献值进行比较。

This makes more and more people pay more attention to studies and applications of numerical simulation in thermal recovery. In this research, we have developed a reliable mathematical model for thermal recovery, which takes a full consideration of the effect of viscos, gravitical and capillary forces on the three-phase flow of gas, water and oil, the effect of the temperature on the medium characteristics of liquid and solid, the phase equilibrium of gas-liquid in each component, heat transportation including connection, conduction and radiation as well as heat losses in both the overburn and underlying strata. In the space discreation of the mathematical model, we have proposed a new method based on the improvement of the conventional nine-points difference approximation, which has a higher difference accurancy.

本项研究以热力采油的主要机理为基础，充分考虑在粘性力、重力和毛管力作用下油水气三相流动，考虑温度对各种流体和固体介质物性的影响，考虑每一组分中汽液两相的相平衡，考虑热在地层中的传导、对流和辐射以及上下盖层的热损失，利用热力学第一定律、质量守恒定律和流体迁移定律，建立了正确可靠的注蒸汽数学模型；在对数学模型进行空间离散时，利用控制有限体积积分法，对以往的九点差分近似作了合理的改进，使其具有较高的差分近似精度：结果表明，该公式的近似精度要比以往文献中所给的九点差分近似精度高，可以认为，在油藏数值模拟中，如果遇到非均质情况，使用这种九点差分近似更合理。

By using of the elastic approximation model and scattering matrix method, we investigate the acoustic phonons transport and thermal conductance in a H-branch four-channel nanostructure.

利用弹性近似模型和散射矩阵方法，研究了低温下多通道量子结构中的弹性声学声子输运和热导的性质。

This thesis research is to develop a new method named "equivalent capacitance approximation" for studying the equivalent circuitry and system power of operating organic light-emitting devices.

中文摘要本论文研究是使用新发展的等效电容逼近法来探讨有机半导体发光元件的等效电路阻抗及负载功率的量化。

The new IRS algorithm has greatly improved the approximation performance of the original reduced set method by embedding a new distance metric called image Euclidean distance into the kernel function.

其中，所谓IRS算法是指在精简集算法的核函数中嵌入一种新的距离度量——图像欧式距离——来改善其迭代近似性能，IRS可以有效地生成新的、位于类别边界附近的虚拟样本以增强给定训练集。

On the basis of the previous studies on sound field separation techniques and based on the Euler formula and the finite difference approximation technique, a new theoretical formula of NAH using pressure and particle velocity measurements is given, and then an experiment is performed to validate the method.

随后通过实验检验了该方法在有背景源干扰情况下实现声场分离和重建的有效性。

It provides a way to find optimal lower dimensional approximations of the given data, and It enormously reduce the storage of the data which is needed when the physical processes is recurred. The physical process can be described in series expansion function that only is related to the time and space. It is optimal approximation of the given data in a certain least squares optimal sense. The most obvious advantage of the method is that it reduces the computation cost and computation time markedly.

它提供了一种描绘物理过程的有效方法，该物理过程可以写成一个只与时间相关的函数和一个只与空间相关的函数的展开式序列，且它们在均方意义上是最优的，在展开式中只需要少量的项数就可较准确地描述该物理过程，因此降低计算维数、减少计算量和节省计算时间是这个方法最明显的优点。

Pachomius manual labour was organized as an essential part of the monastic life; and since it is a principle of the monks as distinguished from the mendicants, that the body shall be self-supporting, external work of one sort or another has been an inevitable part of the life ever since.

根据圣pachomius体力劳动组织作为一个重要组成部分寺院生活；以来，这是一个原则的和尚，作为有别于乞丐，该机构应自支撑，对外工作的这种或那种已一个必然的一部分，生活至今。

In order to study the effects of parametrical rolling on the ship movement and tilts, in allusion to ship's navigating in regular following waves, the equation of ship rolling motion is transformed into normal Mathieu equation by proper variable replacement when strong parametrical excitation in restoring moment varied according to sine or cosine wave.

为研究参数横摇对船舶运动和倾覆的影响，通过对船在规则波上随浪航行时，恢复力矩中出现的1个以正余弦规律变化的强参数激励项进行适当的变量置换，将船舶的横摇运动方程转换成标准形式的Mathieu方程。