结构方程

The sliding mode control was used in the design of the outside loop of PMSM based on decoupling state equation of it.

基于永磁同步电动机的解耦状态方程把滑模变结构控制方法引入到外环的设计中。

The parabola equation that can be fixed to the test curve and has reliable physical meaning was given.

该方程的极值点确定了最佳掺杂含量与晶体结构和制备方法之间的定量关系，进而得到了一个最佳掺杂含量的表达式。

Based on the structure of a non-tracking internal-concentrator solar PV-thermal tube collector and the absorber design requirements, the optical design for the compound parabolic concentrator with half cylinder absorber is proposed to improve the solar energy efficiency. Matlab software was used for the optimization and simulation of the concentrator curve and shape. The curve equation of concentrator for maximum incidence of light of the collector was obtained; and the installation locations for CPC/half cylinder absorber and the necessary CNC processing parameters were optimized.

针对非跟踪内聚光光电－光热复合管的结构及接收器的设计需求，对管内具有特殊形状的半圆柱接收器的复合抛物面聚光器进行了光学设计，并利用Matlab软件对聚光器曲线和形状进行了优化与数据仿真，得到了光热复合管能够得到最大入射光的聚光器的曲线方程、安装位置以及供数控机床加工所需的参数，给出了不同入射角的光线和光强分布图，提高了太阳能的利用率。

First, the paper proves the well-posedness of the encryption and decryption problems, which provides theoretical bases for experiments of encryption and decryption; Then presents a fast iterative algorithm, which is proposed based on the special sparse structure of the coefficient matrix of the two-dimensional C-N difference scheme, and successfully experiments on images encryption and decryption; At the end, the security of the methods of images encryption and decryption based on the two-dimensional Pseudo -parabolic Partial Differential Equation is experimented and discussed particularly.

首先证明了基于二维连续模型的加、解密问题是适定的，为加、解密实验提供了理论依据；然后根据模型的二维C-N格式系数矩阵的特殊稀疏结构，给出快速迭代求解算法，并成功地进行了图像加、解密的数值试验；最后对基于二维伪抛物型方程的图像加、解密方法的安全性进行了详细的试验讨论。

Based on the new explicit parametric solution to the generalized Sylvester matrix equation, a parametric approach for eigenstructure assignment via output feedback is proposed.

基于广义Sylvester矩阵方程新的显式参数解，提出了输出反馈特征结构配置的一种参数化方法。

Based on the proposed analytical general solution of the second-order Sylvester matrix equation,a parametric method of the state feedback eigenstructure assignment in a class of vibration second-order linear systems is presented.

基于二阶Sylvester矩阵方程的解析通解，给出了振动二阶线性系统的状态反馈特征结构配置设计参数化方法。

Finally,a numerical example shows the simplicity and effectiveness of the analytical general solution to the second-order Sylvester matrix equation and the parametric method of state feedback eigenstructure assignment.

最后，数值算例表明二阶Sylvester矩阵方程的解析通解和状态反馈特征结构配置设计参数化方法的简单有效性。

Based on the proposed ana- lytical general solution of the second-order Sylvester matrix equation, a parametric method of the state feedback eigenstructure assignment in a class of vibration second-order linear systems is presented.

基于二阶Sylvester矩阵方程的解析通解，给出了振动二阶线性系统的状态反馈特征结构配置设计参数化方法。

This paper takes the small fish of Carangiform as the mimetic object. Through the bionics study to the principle of Carangiform"s propulsion, the robofish"s main body mechanism that has two degrees of freedom tail fin and single degree of freedom pectoral fin has designed. At the same time, the parameterized mathematical model of double-hinged propulsion system has established. The kinematics analysis, dynamics analysis to the propulsion process and preliminary hydrodynamics analysis to the tail fin and the pectoral fin have been completed. The dynamic equations to the propulsion system have been established.

本文以鲹科模式鱼类为仿生对象，通过对鲹科模式鱼类游动机理的仿生学研究，设计了两自由度的尾鳍推进机构及单自由度的胸鳍机构的机器鱼机械本体结构，建立了参数化的两关节尾鳍推进模式的数学模型，并对推进过程进行了运动学、动力学分析，建立了推进系统动力学方程，对尾鳍和胸鳍推进的水动力进行了初步分析。

Xi ′ an Jiaotong University, Xi ′ an 710049, ChinaAbstract : Propagation of generalized Rayleigh wave in a layered piezoelectric structure with initial stress is investigated. It involves a thin elastic layer bonded perfectly to a piezoelectric elastic substrate.

摘 要：通过求解考虑初应力时的耦合波动方程，研究了覆盖层为各向同性材料、基底为横观各向同性压电材料的压电层状结构中广义Rayleigh波传播时初应力和相速度的关系。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。