查询词典 difference equation

According to the computational stability analysis conducted to the linear term time difference scheme in simple harmonic motion equation, one new semi-implicit integration scheme also is designed. By adopting a kind of revised time-explicitdifference scheme to these linear terms still included in spectral model governing equations, this defect of spectral model only partly used in semi-implicit integrating scheme, can be overcome to some degree.

以简谐振动方程中线性项时间差分格式对其计算稳定性影响为理论依据，本文设计了一种新谱模式半隐式时间积分方案，此方案通过对一般谱模式求解框架中那些隐含的线性项采用了一种显式修正的差分格式，可有效克服其国际谱模式半隐式时间求积方案实质上只是部分应用了半隐式差分格式的问题。

In this dissertation, the numerical method solving the model equation influid motion in some sense has solved some tough problems which traditionalmethods cannot, as in the case of capturing shockwave, enhancing resolution, andspeeding computation. In terms of capturing shockwave and enhancing resolution,this method has proved to be superior to difference method; in terms of speedingcomputation, superior to TVD scheme. Particularly, it is highly effective to solveodd singular solution problems.

本文研究的求解描述流体运动的若干模型方程的数值方法，在一定程度上解决了传统方法在某些方面的难点问题，如在捕捉激波、提高分辨率方面优于差分法，在计算速度方面优于TVD格式，特别是对处理有奇异解的问题很有效。

Based on the wave equations of electromagnetic field, a new time-domain numerical method-direct difference solution of vector wave equation is researched. Calculating formulas of electric field and magnetic field are also given.

对电磁场波动方程进行了分析，研究了一种基于电场波动方程的时域数值方法―矢量波动方程的直接差分解法，给出了电场和磁场的计算公式。

If the neighborhood of equation solution is solvable and meets the point- by-point Lipschitz condition, stable boundary could be obtained as the convergence of the difference method is realized, and thus the stability is ensured.

方程解的邻近如果可解并具备逐点Lipschitz条件，则差分法收敛必有稳定界存在，从而差分格式收敛性保证其稳定性，因此可以放弃线性这一重要条件。

Because the items be introduced,difference of composite with imperfect interface from one with perfect interface is that stationary value principles of the former is no longer equivalent of variation equation s corresponding the principles.

与完美界面不同的是，由于这个积分项的引入，非完美界面复合材料的驻值原理不再与相应的变分方程等价。

It was found that sulfuric acid, 2-naphthalenesulphonic acid and sulfurous acid could be effectively separated by competitive exchange adsorption in views of action force difference of the components with the resin. The exchange adsorption dynamic diffusion parameters were calculated with diffusion equation for solids and liquid films, and the rate-determining step was determined. The model of breakthrough curve for the resin bed was suggested, and applied to simulate the breakthrough process for each component.

通过单组分、双组分和多组分平衡数据的测定，发现对于硫酸-萘磺酸-亚硫酸混合体系，可以利用不同组分与树脂作用能的不同，通过竞争交换吸附实现分离；以固相扩散方程和液膜扩散方程对交换吸附动力学参数进行了估算，确定了交换吸附过程的控制步骤；建立了床层穿透曲线模型，并对各组分穿透过程进行了模拟。

Based on the model, the gas non-dimension Reynolds equation is listed and studied by the two-dimensional Taylor formula and limited difference method.

根据模型，列出了簧片下气体运动的无量纲雷诺方程，并利用二维泰勒展开式和有限差分法对其进行了分析。

By use of the time split method, a conservation difference formula is established to find the solution to the shallow water equation based on the finite volume control method from integral equations.

作者中文名：李光炽；王船海；周晶晏摘要：采用二分步法，从积分型方程出发，在有限控制体上建立守恒型差分格式，对二维浅水波方程进行求解。

After a further analysis based on the empirical results,a trial probe on the cognitiveprocessing mechanism of the problem representation of the word problem in two types of MLDwas made by the author.The MRD performed much poorer than the MLD only in the mostdifficult equation listing of word problem and the medium and most difficult problemrepresentation of word problem,which showed no difference in computation and comprehensionof simple meaning of the problem,but the gap between two types of MLD became wide as afunction of difficulty and cognitive loading.It indicated that the MLD only had some advantage over MRD for they used more cognitive skills to solve the problem.

基于以上实验的结果，对两类数学困难小学生的应用题问题表征的认知机制作如下推断：混合型数学困难学生仅在高难度水平的应用题列式成绩和中高难度水平应用题问题表征水平上比单纯型数学困难学生得分显著低下，表明两类数学困难小学生在计算能力与理解简单题意的能力上并无差异，但随着难度提高，认知负荷加重，两类数学困难学生在应用题解题上的差异得以突显，表明当需要运用更多的认知能力解决问题时，单纯型数学困难学生比混合型困难学生更具优势。

The obtained results a re compared with analytic solution and those from integral equation and other me ans. It is shown that the staggered grid finite difference method combined with the Biconjugate gradient iterative solver processed with divergence correction and incomplete Cholesky decomposition procedures can efficiently improve the three dimensional electromagnetic calculation with high accuracy and stability.

经与解析方法、积分方程等其他方法的计算结果对比表明，交错网格有限差分法结合散度校正和不完全乔累斯基分解预处理的双共轭梯度迭代方法进行正演计算，速度快、精度高、结果稳定，能适应三维复杂介质的数值模拟，为三维电磁反演奠定了基础。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。