导数

Dynamic derivatives of a 60° delta wing and F-18 aircraft model are calculated by this method, and then the effects of the amplitude,the frequency and the change of angle of attack on the dynamic derivatives are studied.

对60°三角翼和F-18飞机模型进行动导数仿真计算，研究了不同振幅、频率及迎角变化对动导数的影响。

Based on the quotient of difference being the grey derivative's whitening values in the GM(1,1) direct modeling method, direct modeling method of GM(1,1) with a step by step optimum grey derivative's whiting values is put forward.

在 GM(1，1)直接建模法以差商作为灰导数白化值的基础上，提出了一种逐步优化灰导数白化值的方法。

And then the sufficient conditions of differentiability for the multivariate function is considered.

然后考虑了一般的多元函数的情形，得到了当多元函数的某个偏导数连续，而其余偏导数存在时，函数可微。

If all of the partial derivations exist and only one of them is not continuous,the multivariate function is differentiable.

最后结合实例进行了讨论，结果表明，所有偏导数存在并不蕴含可微，函数可微时可以没有连续的偏导数。

First of all, it is proved that if one partial derivation is continuous,the other partial derivation exists,the binary function is differentiable.

首先证明了当二元函数的一个偏导数存在，另一个偏导数连续时，函数可微。

Reduce the computing complexity of magnetic field integral equation with differential quotient, which makes the computing which combined field integral equation more efficiently.

在AIM算法的实现技术方面作了两个改进：一是采用了新的多极子展开方案，保证了迭代的数值稳定性；二是在差商逼近偏导数的过程中全部采用二阶形式，保证了差商逼近偏导数的精度。

However,the derivative of this error,the slope of the error curve,is large and positive,making the control correction provide by the derivative mode large.

然而，错误的导数和误差曲线的斜率较大且为正，导数模式提供了很大一部分的控制校正。

This model used the finite—difference approximation to the advection— dispersion equation. The spatial derivatives in the flow equation are approximated by central difference written about grid—block boundaries and time derivatives are approximated by a fully implicit backward scheme.

水流方程的空间导数采用中心差分格式离散，时间导数采用隐式差分格式离散，建立了土壤水分和污染物在各种饱和度的条件下迁移转化方程耦合求解的二维数值计算模型。

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。

Do not gum up the work by telling mother what we are going to do .

别告诉母亲我们要干的事，那会把事情搞糟的。

In recent years, application of the partial prestressed concrete beam s is developed.

近年来，随着部分预应力砼梁应用的推广，发现我国规范所采用的名义拉应力法的计算结果不稳定。