查询词典 calculus of finite difference

In the numerical computation, a two-dimensional numerical method integrating finite element method and difference method was employed, where the finite element method is used to calculate the magnetic field of the permanent magnetic guideway and the difference method is used to calculate the induced current in the superconductor, then the levitation force and the lateral force were calculated by Lorentz formula.

在数值计算部分，实现了一种集有限元法与差分法为一体的数值计算方法。

But the finite difference methods require that the computational domain is regular, and usually people construct the finite difference scheme for one dimension and then extend it to two or three dimensions in a dimension by dimension fashion.

有限差分方法要求计算区域比较规则，随着工程问题的复杂化，计算区域也变得复杂，这对数值方法提出了新的挑战。

In this paper, the maximum likelihood algorithm with process and measurement noise for nonlinear continuous-discrete system given by Jategaonkar and Plaetschke is improved in two aspects: 1 to avoid the disadvantages of sensitivities computation by common finite-difference method, in which the perturbation sizes should be selected optionally, an improved finite-difference method with best perturbations, is presented. 2 to improve the numerical stability of Jategaonkar's algorithm, maximum likelihood algorithm with fast triangular square-root decomposition filter is given.

摘要对Jategaonkar等人给出的同时计及过程及观测噪声的非线性连续-离散系统的极大似然算法从两个方面进行了改进：1给出了计算灵敏度的最佳摄动有限差分算法，避免了普通有限差分法计算灵敏度矩阵时需人为选择参数摄动量大小而带来的缺点；2给出了具有快速三角化平方根滤波的极大似然算法，提高了原算法的数值稳定性。

In order to analyze vertical bearing behavior of large diameter belled pile in soft substratum, three-dimensional non-linear finite-difference numeric models are established with finite-difference program, calculated and measured results are contrasted, and it proves that the calculation models and the chosen parameters are rational.

为分析存在软弱下卧层的大直径扩底桩的竖向承载性状，本文利用有限差分程序建立三维非线性有限差分数值模型，将计算结果与实测数据进行对比，验证了计算模型与参数选取的合理性。

Employing the finite difference calculus, the cavitation bubble pulsating performance with the change of liquid viscosity, gas content, surface tension and condensability is obtained.

在系统地研究固壁面附近空泡溃灭过程的基础上，提出并研究了射流阈值、空泡在第一次和第二次脉动过程衰减蚀除机理以及空泡溃灭周期延长因子等问题。

Employing the finite difference calculus, the cavitation bubble pulsating performance with the change of liquid viscosity, gas content, surface tension and condensability is obtained. In the experiment research, the detailed processes of capitation bubble oscillation property and bubble collapse are gained by the fiber-optical detection sensor. Furthermore, th...

本文研究结果既可避免激光等离子体冲击波和空化带来的危害，也为合理利用激光等离子体冲击波和空化现象提供理论和实验依据，可供激光加工、激光医疗、水下激光加工和相关流体力学的研究参考。

Firstly, the approach formulates a cost functional to turn the inverse problem into a constrained minimization problem according to least squares criterion, then the resulting constrained minimization problem is transformed into an unconstrained minimization problem by using a penalty function technique, and then the closed Fr chet derivatives of the Lagrange function with respect to the properties are derived based on the calculus of variations, finally, one can solve the resulting problem by using any gradient-based algorithm and the finite-difference time-domain method.

该方法首先以最小二乘准则构造目标函数，将逆问题表示为约束最小化问题；接着应用罚函数法转化为无约束最小化问题；然后基于变分计算导出闭式的拉格朗日函数关于特征参数的Fr chet导数；最后借助梯度算法和时域有限差分法迭代反演德拜模型参数。

With the publication of the Dai Wei Ji Shi Ji, a translation of Loomis' textbook Elements of Analytical Geometry and of the Differential and Integral Calculus (1851), in 1859, the differential and integral calculus was introduced into China.

19世纪后期是中国数学由传统向近现代转化的一个重要时期，微积分是近代数学乃至大部分自然科学的最基础的理论，这个理论是从1859年出版的译著《代微积拾级》中介绍到中国来的。

The objective of this investigation was to compare the pharmacodynamics of Sheng Wu Niu Huang with those of the natural calculus bovis and the artificial calculus bovis from the acute toxity, antipyretic effect, hypnotic effect, anticonvulsive effect, anti-inflammatory effect, antiviral effect and the influence on the hemorheology.

运用比较药理学方法将生物牛黄中间体与天然牛黄、人工牛黄从急性毒性试验、解热作用试验、催眠作用试验、抗惊厥作用试验、抗炎作用试验、抗病毒作用试验以及对血液流变学影响等方面进行了药效学比较研究。

Taylor Formula is a very important content of mathematics analysis ,it can focally embody the soul of " approximation" of calculus. And is extensively applied in most aspects of calculus.

泰勒公式是数学分析中非常重要的内容，集中体现了微积分"逼近法"的精髓，在微积分的各个方面都有重要的应用。

Listen,point and check your answers.

听，指出并且检查你的答案。

Warming needle is one of effective treatment methods for knee arthralgia aggravated by cold,and it is simple,safety,so it should be developed in clinical acupuncture and moxibustion extensively.

但以本院科针灸门诊在2005年1月—2006年6月期间共收治膝痛患者100余例，经过临床的诊断后，其中施以温针治疗的48例，疗效显著，报道如下。1临床资料本组病例48