一阶理论

The existence of periodic solutions to the second order ordinary differential equation in Banach space is discussed.

本文利用半序理论，非紧性测度，凝聚映射的拓扑度，不动点定理及锥上不动点指数理论，讨论了Banach空间E中二阶常微分方程周期边值问题解的存在性，主要结果有一。

Firstly, some fundamental knowledge, such as the describing of laser field, the Kind of electron-atom scattering in a laser field, and so on, are introduced. Then a compution method which is called the Second-order Born approximation and is used to calculate the cross section of electron-atom scattering in a laser field, is provided.

本文首先介绍了激光场的描述、激光场中电子—原子散射的分类等相关理论，接着详细描述了一种计算激光场中电子—原子散射截面的方法——二阶玻恩近似理论。

In this paper, a general, strain-consistent, third-order displacement field of shells is proposed. On this basis, the nonlinear theory of composite laminated shells including third-order transverse shear deformation and rotary inertia is developed. Hamilton's variational principle is used to derive the nonlinear static and dynamic governing differential equations and the corresponding boundary conditions of composite laminated anisotropic general shells under the orthogonal curvilinear coordinates. And the form of spherical shells is degenerated.

本文提出了一种最普遍的应变协调、三阶壳体位移场，在此基础上建立了考虑三阶横向剪切变形和旋转惯性的复合材料层合壳体非线性理论，用Hamilton变分原理导出了复合材料层合各向异性任意壳体在正交曲线坐标系下的非线性静、动力控制微分方程和相应的边界条件，并将其蜕化为球壳形式。

Meanwhile, this paper systematically summarized the present fractional-order control theory results distributed mostly in such aspects as continuous and discrete time domain analysis, approximated numerical analysis, common frequency domain analysis, plane locus method based on variable transposition, etc, and became an effective foundation of forming a complete control and system theory for fractional-order control systems.

同时，论文对当前国内外已有的分数阶控制理论成果进行了较为系统的整理，主要集中在连续和离散时间域分析、近似数值分析、一般复频域分析、基于变量变换的平面根轨迹分析等方面，具有综述性质，是建立一套完整的分数系统控制理论与系统理论的有效基石。

A new switching scheme to the gain of variable structure control signals is proposed. The following important open problems in standard VS-MRAC and MRAC are solved by using the scheme: 1 . a prespecified transient and steady-state performance index for tracking error can be achieved without requiring any information about the plant high frequency gain sign when relative degree of modelled part of plant is one, and 2 . it is shown that as long as the performance indexes are guaranteed for the auxiliary errors, each of which in dynamics is a sub-system with relative degree one, the tracing error will converge to a small residual set in a prespecified transient time when relative degree of modelled part of plant is greater than one.

提出了一种控制增益可切换的变结构自适应律，解决了如下变结构模型参考自适应控制（包括基于调参律的模型参考自适应控制）理论研究中长期没有解决的问题：当对象建模部分相对阶为1、高频增益符号未知且存在非线性输入扰动和未建模动态等情况下，系统跟踪误差可满足预先给定的动态和稳态性能指标；当对象建模部分相对阶大于1且存在非线性输入扰动和未建模动态时，可保证系统跟踪误差在预先给定的过渡过程时间内收敛到一个残差集中； 5。

By using the second order Stokes wave theory,the wave force is calculated and the method to deduce the formula of the second order Stokes wave force spectrum is explored.

本文基于二阶Stokes非线性波浪理论探讨了采用非线性波浪理论时随机波浪力谱的计算方法，并用一典型算例，对本文公式的计算结果与线性波理论的计算结果进行比较。

By using the second order Stokes wave theory, the wave force is calculated and the method to deduce the formula of the second order Stokes wave force spectrum is explored. A representative example is given and the results horn calculation are obtained in the form of curves for comparison.

本文基于二阶7Stokes非线性波浪理论探讨了采用非线性波浪理论时随机波浪力谱的计算方法，并用一典型算例，对本文公式的计算结果与线性波理论的计算结果进行比较。

For the singular spectrum analysis of time series, a method of constructing covariance matrix by using forth order cumulant is proposed. The method could restrain the Gaossian noise and symmetrical distributed noise mixed with chaotic signals.

对于时间序列的高阶奇异谱分析，提出了一种利用四阶累积量函数构造协方差矩阵的方法，该方法从理论上能有效地抑制叠加在混沌信号中的高斯噪声和对称分布噪声对重构结果的影响。

In the first section,the existence of solution for a class of non-linear systems with three -point boundary problem is obtained by applying the differential inequality theory .

在第一部分中，我们应用微分不等式理论证明了一类非线性系统三点边值问题解的存在性；在第二部分中，运用微分不等式理论研究了一类带有转向点的拟线性奇摄动边值问题的非单调内层解；在第三部分中，利用对角化方法研究了一类向量二点或者三点边值问题解的存在性，并获得解及它的一、二阶导数的渐近估计。

By means of using a disc cutter with a concave end instead of traditional ball-ended or flat-ended ones,and adjusting the cutter axis to move relatively to the component being machined according to some special rules,the envelop formed by the trace of the tool-nose in each pass and the required surface have the same derivatives up to the second order in the plane normal to the feeding direction.

采用二阶密切曲率法，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阶？

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。