一阶导数

And that method is different from the adding base point method and impact method from importing derivatives of higher order.

他与增加基点数目的方法和引入高阶导数的紧致方法不同，是微分方程差分近似高精度化的一种新方法。

It is a generalization of the nonlinear diffusion equation proposed by Perona-Malik and the method presented by Cuesta, and interpolates between the nonlinear parabolic equation and the nonlinear hyperbolic equation, thus can effectively control the diffusion process so that noises can be removed and details of the image such as edges can be preserved as much as possible simultaneously.

提出了一种包含对时间的分数阶导数的非线性扩散方程，它是对Perona-Malik的非线性扩散方程和Cuesta提出的方程的推广，介于非线性抛物方程和非线性双曲方程之间，从而能有效地控制扩散过程，使得在去除图像噪声的同时能够尽可能地保留图像的边缘等细节信息。

It is proved by the analytical and numerical method that the modulus of the Z transform of a finite impulse response sequence has no extreme values at poles (with maximums along imaginary axis and no extreme values along real axis), and the negative second order derivative of the modulus normalized along frequency axis with respect to angular frequency has maximums at the poles.

根据实测瞬态电磁脉冲响应，较好地反演了导体球和导体长椭球的冲激响应，测得了它们的雷达截面和谐振频率。用解析与数值相结合的方法证明了有限冲激响应序列Z变换的模在极点无极值（沿虚轴有极大值，沿实轴无极值），而沿频率轴的归一化值对角频率的负二阶导数在极点有极大值。

A kind of method to determine boundary conditions of interpolating quadric spline function with halfknots as conjunction points, which is C 1 continuous but its second derivative function is piecewise constant, is obtained by means of least squares.

鉴于此，本文利用最小二乘法，获得了一种半节点二次插值样条边界条件确定方法，该方法可以保证二次插值样条在半节点处二阶导数的变化最小，这相当于保证了曲率的变化最小。

A new static image reconstruction method for EIT based on genetic algorithm is proposed in this dissertation. It is quite different from the traditional modified Newton-Raphson iterative method based on minimizing the object function.

本文提出一种基于遗传算法的静态EIT图像重建方法，它完全不同于传统的基于目标函数梯度或高阶导数信息的Modified Newton-Raphson优化迭代算法。

The first and second derivatives of the coordinates of a cam profile are calculated using numerical differentiation method,and substituted with curvature radius formulas in calculus,thus obtaining its curvature radius.

应用数值微分法计算凸轮廓线坐标的一、二阶导数，代入微积分学中曲率半径公式，即得凸轮廓线的曲率半径。

We constructed a finite volume scheme of fifth order Hermite type with high accuracy for twopoint boundary value problems, choosing trial and test spaces as the fifthorder finite element space of Hermite type and the piecewise linear function space respectively. We didn't use higher derivatives as interpolation conditions, which is the same as the thirdorder finite element of Hermite type, but the scheme obtained had higher accuracy.

构造求解两点边值问题的一种Hermite型五次元高精度有限体积法，其中试探函数空间取Hermite型五次有限元空间，与Hermite型三次元相同，未引入更高阶导数作为插值条件，检验函数空间取分段线性函数空间，这样构造的格式求解精度更高。

Results By using containing ethanol-2mol·L -1 lithium chloride-water(2∶1∶5)solution,there is a very good secondary derivative differential pulse polarogram peak at -1.703 V.

结果 ：秦皮甲素在乙醇- 2mol·L- 1 氯化锂-水(2∶1∶5 )的底液中，于- 1.70 3V处出现一良好的二阶导数差示脉冲极谱法峰，其峰幅值与秦皮甲素在 0 。2～ 1.6mmol·L- 1 范围内呈良好的线性关系(r =0 。9998)，检测限为 5 0nmol·L- 1 。

This factor has been dubbed "the second derivative", or the rate of change of the rate of change.

这一因素被称为是"二阶导数"，或者是变化率的变化率。

In this paper an innovative method for machining sculptured surfaces is presented. By using a disc cutter with a concave end instead of traditional ball-ended or drum-shaped tools, and adjusting the cut- ted axis to swing relative to the component being machined under some special rules, the envelope formed by the trace of the tool-nose may have the same derivative up to the third order as the required theoretical surface.

本文提出了一种加工自由曲面的新方法，即采用中凹的盘形铣刀取代传统的球头或鼓形铣刀，在每一行程中让刀具轴线相对于工件按特定的规律摆动，使得在垂直于进给方向的法截面中，由刀尖轨迹形成的包络面与理论曲面的法截线具有相同的1～3阶导数，从而在保持精度不变的前提下，使实际行程次数得以大幅度的减少。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。