模态

A novel sliding-mode control is designed with a load thrust observer for the Linear Permanent Magnetism Synchronous Motors,in order to compensate the disturbance and effectively minimize the system chattering;introducing an integral action in the sliding mode to eliminate the system error and chattering.

针对永磁同步直线电机提出了一种基于负载推力观测器的新型滑模变结构控制，从而实现对推力扰动的补偿，且大大削弱了推力纹波及系统的抖振；在滑动模态中引入积分环节来进一步消除系统的稳态误差和系统抖振。

Due to the symmetry of the plate, there are symmetric and antisymmetric mode vibrations with respect to the median plane of the plate.

首先建立了在偏压电场作用下压电介质的运动微分方程，进而根据对称模态和反对称模态的特点，分别在自由表面电学开路和电学短路情况下得到了Lamb波传播的相速度方程。

The results show that more modalities can be excited from asymmetric system and that there is little difference between the power flow spectra of rigid raft system and flexible raft system in middle and low bands of frequency, but there is considerable difference at high frequency.

研究结果表明，非对称系统能激励出更多的模态；在中低频段弹性浮筏系统和刚性浮筏系统的功率谱没有很大的区别，但是在高频段差别则很明显，浮筏的弹性模态起着主要作用；减小隔振器的刚度并适当增加隔振器阻尼不仅可以降低传递到基础的功率谱，同时还可以抑制共振减小冲击。

Vibration Modal analysis and parameters identify is an analysis method which is used in "athwart question" in the Structure Dynamics.

模态分析的最终目标是识别出系统的模态参数，为结构系统的振动特性分析、振动故障诊断与预报以及结构动力特性的优化设计提供依据。

There are three parts in our design: first, the dual-band branch line coupler provides two equal-power signals with 90° or -90° phase difference in each operating band. Second, the wideband switching circuit controls the two output powers of branch line coupler to excite the antenna structure for producing linear polarization wave or circular polarization wave. Third, the L-shaped fed conventional planar patch antenna is provided to overcome the coupling effect.

整体架构包含三个部分：L形电容耦合馈入式平面天线是为了克服平面式微带天线窄频的缺点；双频枝干耦合器提供天线在操作的两个频率点上各输出两组相差正九十度与负九十度的讯号，最后宽频的切换电路是将枝干耦合器的两组讯号作分配用以激发不同方向的天线以产生线性极化模态或同时激发两个垂直的天线以产生圆形极化模态。

A time-frequency analysis method based on HOS is proposed to study the girder gust response, and the supreme mode contributed to gust response and the modal coupling could be identified using this method.

二、提出利用基于高阶谱的时频分析研究大桥非平稳、非线性风致振动响应，能够得出对不同测点风致振动响应贡献最大的模态和耦合振动模态。

Firstly, modal responses were estimated by the application of robust second-order blind identification technique on the measured vibration signals. And then, modal shapes were extracted from the de-mixing matrix above. Finally, frequency and damping ratios could be obtained from the modal responses using each single degree of freedom mode.

运用该法提取系统／结构模态参数的步骤为：首先利用稳健SOBI的盲源分离方法采集的信号进行分离，然后将分离矩阵作为结构／系统的模态振型矩阵，最后再对各个分离后的单自由度信号提取频率、阻尼比参数。

The simulation results of liquid propellant rocket engine demonstrate that modal interval analysis is effective to complex dynamic systems.

通过对某泵压式液体火箭发动机稳态工作过程的模态区间仿真计算，证明模态区间分析方法对复杂动态系统建模仿真是有效的。

Thirdly, based on the continuum model, the natural modes of undamped complex framed structures are proved to be orthogonal with each other in a generalized sense. This leads to an alternative method for transient response analysis of undamped framed structures via the expansion of normal modes.

再次，基于MRRM列式，从连续模型的角度证明无阻尼复杂框架结构的固有模态具有正交性，并以此为基础构造模态叠加法来求解无阻尼复杂框架结构的瞬态响应。

The modal testing measures the frequency call function of test points on scatter-gun and recognizes the step modal parameters by single point momentary stimulation and multi-points measuring.

全枪模态试验通过单点瞬态激励、多点测量方法，测出机枪上各测点的频响函数，识别出机枪的各阶模态参数。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。