查询词典 approximation methods in physics

We construct an explicit finite difference approximation for the equation by using the equivalence relation between Riemann-Liouville fractional derivative and Grünwald-Letnikovmake fractional derivative.

再利用Riemann-Liouville分数阶导数与Grtinwald-Letnikov分数阶导数之间的等价关系，构造一显式有限差分近似，这一离散格式可以解释为一个随机游走模型，并且收敛于稳定的概率分布。

And we show that random walk model converges to the stable law of Lévy-Feller advection-dispersion equation by use of a properly scaled transition to vanish-ing space and time steps,We propose an explicit finite difference approximation for Lévy-Feller advection-dispersion equation.

第三章讨论描述服从某种稳定分布反常扩散的非对称空间分数阶对流-扩散方程——Lévy-Feller对流-扩散方程，首先利用Fourier变换和Laplace变换给出方程的基本解，然后利用Grünwald-Letnikov分数阶导数移位离散算子离散方程中的Riesz-Feller分数阶导数得到离散格式，证明此格式可以解释为离散随机游走模型，并且证明了当时间和空间步长以一定的比率同时趋于0时，所提出的离散随机游走模型收敛到Lévy-Feller对流-扩散过程的稳定分布。

Af ter applying this result to the conservative gas dy2 namic systems ,the semi2discrete finite difference approximation and the discrete ent ropy couple [Ut , F0j + G1j ] is searched.

关于双曲型守恒方程组ut + f x = 0 ，若存在标量熵对满足熵不等式Ut + Fx ≤0 ，则原方程存在弱解。

The finite summation of real Fourier series approximation of a time pusle.

时间脉冲的实部傅立叶级数接近的有限和。

To a first approximation, I don't really like talking to most people, so I don't go out of my way to enable people to call me.

一个很重要的原因是，我实在是不喜欢和太多的人讲话，因此，在我出去时别人是找不到我的。

My lifestyle is, as a first approximation, invariant to my income.

我的生活方式，如前所述，不会受到收入的影响。

Then an improved design method of resonant tank combining first harmonic approximation and simulation in time domain was proposed.

基于所提出的方法设计的参数建立一台220 W的样机，实验结果证实了所提出改进型设计方法的正确性和可行性。

Equation (4-198) yields a first approximation for the change in the natural frequency of vibration.

方程（4－198）给出了一级近似下的固有振动频率的改变量。

Equation(4-198) yields a first approximation for the change in the natural frequency of vibration.

方程（－98）出了一级近似下的固有振动频率的改变量。

We give a polynomial algorithm for the first problem and an approximation algorithm for the second one.

对于一类具有离散资源约束的排序问题当机器数目固定时本文给出了一个多项式时间算法，对于一类加工时间依赖资源的排序问题给出了近似算法。

We have something to do in the new stage.

在这段崭新的时期中，我们有一些要做的。

The difference between tourism decision-making under uncertainty and risky tourism decision-making is indistinctive.

其中不确定性旅游决策和风险旅游决策的界线比较模糊，两者的区分是相对的。