导函数

One bases on function value and another bases on arithmetic average difference quotient. In this paper, the author mainly studies the approximation properties of both the function value and the derivative of two kinds of splines interpolation mentioned before, and the optimal error constants are obtained finally.

文中分别就这两类插值样条的函数值及一阶导数的逼近性质展开讨论，相应得出这两种插值函数在被插函数分别为一阶连续可导和二阶连续可导情况下的最佳误差常数。

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

First, the partial derivative is defined, based on the convergence in probability measure in the probability measure space.

本文首先在概率测度空间上，利用依概率测度收敛，定义了多随机变量函数的偏导数，并且偏导数的计算式可以通过替换实值函数的对应的偏导数中所有的实变量替换为随机变量得到。

Application of differential coefficient in inequation verification;2. It also elaborates what should be pay attention to while making use of this method to obtain differential coefficient .

本章给出了由分段函数直接求导数再取极限求函数在分段点处导数的方法，并就利用该方法求导数时需要注意的问题进行了说明。

On the basis of analyzing detailedly the correlative conclusions of the extreme value problem of two variable Function , this paper extends the essential condition and sufficient condition to multi-variable function by using the Taylor Formula 、Quadratic Form 、Hesse Matrix and so on,and gives a method to judge the extreme value of point whose vice-derivative doesn't exist by utilizing Lagranges theorem ,so that compensates for the blank above ,which turns idea that solve the extreme value of multi-variable function problem one by one into realities.

摘要本文在对二元函数极值问题的相关结论进行分析的基础上，用泰勒公式、二次型、海赛矩阵作为工具，将二元函数极值的必要条件和充分条件推广到多元函数的情形，而且还利用拉格朗日中值定理找到了一个判别不可导点处极值的方法，从而弥补了多元函数不可导点处极值无法判断的空缺。因而，使得用穷举判断的方法来解决多元函数的极值问题这一思路成为现实。

This paper has utilized the mathematic inductive method and Leibniz theorem to study the unity advanced derivation of complex-special Function and original function, acquired their united expression.

用数学归纳法和莱布尼兹公式对一类复杂函数的高阶导数与原函数的统一性进行了研究，获得了该类函数的高阶导数及原函数的统一表述公式。

A convergence acceleration technique based on functional asymptotic expansion and Poisson's summation formula is developed to raise the calculation efficiency of waveguide dyadic Green's functions which are expanded in infinite series.

为此，作者提出"谱展开边界元法"，以求解波导外空间的并矢Green函数；引入边界元法以求解波导壁内折曲缝隙腔的并矢Green函数；并研究了无穷级数的逐级加速收敛变换，以解决波导中Green函数的计算问题。

About the title of statistic of planar vector, probability, its solve problem process to permeating function form not only, and still permeating function thought; again criterion the tool that derivative is research function, had derivative, function content more appear profundity, rich and colorful.

有关平面向量、概率统计的题目，其解题过程不仅渗透着函数形式，而且还渗透着函数思想；再则导数是探究函数的工具，有了导数，函数内容就更显得深刻、丰富多彩。

It shows that the δ-derivative is identical with the derivative of finite discrete function when the sample points are increased.

引入了连续函数的δ导数新概念，研究表明，在采样点无限增多的情形下，它与有限离散函数导数概念相一致；在极限情形下，它与常规意义下连续函数导数概念相一致。

For acquiring relations between the eigenfunctions of waveguides and tensor Green function, we first take the Fourier transform of Green function. In isotropic media the simplest image function can be expressed in dyadic form, and in anisotropic media in the form of ABA+-ikz0,where A is the coordinate matrix.

为了得到波导管的本征函数和格林张量函数的一些关系，我们首先对格林函数作富氏变换，它的象函数在各向同性介质波导中以并矢形式作为最简单的表达方法，而在充有各向异性介质波导中可以表为ABA~+e~的形式，这里A是坐标矩阵。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。