下模

The strategies of high order sliding mode control and sliding mode control with integral action are proposed. Without losing the virtue of robustness and the ability of eliminating disturbance, these strategies can minimize the chattering phenomenon which is quite common in conventional sliding mode control.

在研究中，提出了高阶滑模控制和带积分的滑模控制方法，这两种方法在保证了常规滑模控制的强鲁棒性和抗扰动能力的前提下，可以在很大程度上削弱抖振，对常规的滑模控制有较大的改进。

The static natural frequencies and dynamic frequencies (under 3000rpm) are calculated by the finite element method and cyclic symmetry technique. The rotating vibration behaviors of the two models are compared. Different vibration characteristics between the two models are discussed. Geometry mismatch in a turbine blade root, which arose in manufacturing process or caused by wearing out during service, leads to contact conditions changed in fir-tree attachments. As a result, shifting of the fundamental frequencies and redistribution of stress in the blade base possibly cause failure of the blade.

在叶片—轮盘耦合系统振动研究方面，建立了带围带的叶片振动计算模型和带围带的叶片—轮盘耦合系统振动计算模型，考虑旋转离心力作用，采用波传播技术，对两种模型分别进行了整圈模态分析，得到了某汽轮机叶片模型和叶片—轮盘耦合模型在0转速和工作转速(3000rpm)下的振动模态，并对所得结果进行分析比较，讨论了整圈叶片振动模态与叶片—轮盘耦合振动模态的区别。

The aims of this paper are to derive the optimal error estimates of eigenpairs, i.e. the optimal error estimate of eigenvalues, and the new error estimates of velocity, pressure including the L~2 - norm and energy norm, respectively, in which the L~2 - norm estimate of velocity on anisotropic meshes has not ever been seen in the precious literature.

对于Stokes特征值问题本文不仅得到了征值对的最优误差估计即：特征值和流速压力的零模和能量模以及压力的能量模最优误差估计，其中在各向异性网格下对此问题的零模估计尚未见报道。

You can find out it is the major temporary work, such as formwork, rebar jig, equipment etc. during the FPLM construction, in which the cost of the inner mould and outer form of box girder, the steel form of pier and pierhead of substructure, the rebar jig as well as the launching equipments are quite high. The quantity of those equipments was always depended on experience in the pass time. Therefore the more of the form quantity is used the higher of direct costs would be spent. On the other hand it would be reduced the capacity of production if the equipments are insufficient.

在全跨预铸工法中所使用的生产设备仔细观察可发现，预铸工法中假设工程(如模版、钢筋加工架以及施工机具等)所占比例相当高，其中有箱型梁的内模与外模床、下构的柱钢模、帽梁钢模、钢筋加工架、吊装机具等所占的成本相当高，以往设备数量多寡均以经验来取决，因此假如模版数量过多直接成本随之提升，反观模版资源数量不足时又会造成生产力降低情况发生。

An instantaneous optimal semi-active control method is put forward. Combined sliding mode control with lyapunov's stability theory, the control weights matrix, which can minimize structural instantaneous energy, is designed. Simulation and shaking table test is conducted to validated the method's effectiveness. To solve combination explosion of controlled structural state encountered in high-rise building control, the semi-active control strategy, which can drive structural state point to reach the sliding mode switching band, is designed by using sliding mode control theory, and genetic algorithm is used to find the optimal semi-active switching to drive the structural state point to sliding mode switching band at prestissimo speed.

提出了一种瞬时最优半主动结构控制方法，利用滑模变结构控制理论和Lyapunov稳定性理论设计使结构瞬时能量最小的半主动控制权矩阵，仿真实例和振动台试验验证了本文所提方法的有效性和实用性；为解决在高层建筑半主动控制中半主动控制器状态组合爆炸的问题，利用滑模变结构控制理论设计在Lapunov稳定意义下使结构在运动状态空间中任一相点于以最快速率到达滑模切换带的半主动控制策略，并用遗传算法找出了最快到达滑模切换带的半主动控制切换组合。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

Plate and λ/2 plate were placed inside the Nd∶YVO4KTP green laser cavity with angle 90°between their fast axis.The composite plate composed of HWP,QWP and KTP has the function of QWP.The composite plate with Nd∶YVO4 can effectively suppress the coupling of polarized modes,and multi-longitudinal-mode lownoise green laser was obtained.Since the composite plate counteracted the phase shift induced by temperature sensitivity of quartz plate,the green laser operated with lownoise reliability in different output power and different operation temperature.The threelongitudinalmode, the noise of less than 0.5% and output power stability of less then 1% for 12 hour are obtained in the green laser.

介绍了一种LD泵浦腔内倍频全固体Nd∶YVO4KTP多纵模、低噪音、高功率稳定绿激光器在Nd∶YVO4KTP绿激光器组成的谐振腔内放置厚度约相等的石英晶体λ2波片和λ4波片，使两波片快轴夹角互呈90°，HWP、QWP与KTP构成复合波片，其作用相当于QWP，此复合波法与各相异性Nd∶YVO4共同作用有效抑制了腔内偏振模耦合，获得多纵模低噪音绿光输出此复合波片相互作用由于抵消了石英晶体波片温度敏感引起的相位延迟量漂移，所以此激光器在不同功率、不同工作温度下，均能稳定可靠地运转于低噪音状态实验结果为，绿光输出纵模数为3个，噪音小于0.5%，12 h功率稳定性优小于1

This paper analyzes the principle of the LP-LFC process,presents the physical and mathematical models of mould filling of the new process. The patterns including window-plate, ladders cluster, electromotor frame and exhausting manifolds are poured using LP-LFC process with AZ91D alloy, and the mould filling course is tracked with electrode touch point method. Based on above tests and experiments,the casting defects including short runs, cold laps, trapped gas,metal penetration, and so on, were investigated. The appearance characteristics,birth causes and influence factors of above defects are discussed in the article,diagrammatize modes of the defects forming is also given, and the measures of reducing or avoiding defects are put forward.

本论文分析了低压消失模铸造技术的工艺原理，建立了低压消失模铸造过程中金属液充型的物理和数学模型；在各种工艺条件下浇注了薄板窗体、阶梯模样簇、电机外壳和发动机排气管四个典型的模样和产品，用电极触点法记录了镁合金低压消失模铸造的充型过程；试验研究了镁合金低压消失模铸造中出现的浇不足、冷隔、气孔、粘砂等典型缺陷，分析了这些缺陷的形貌特征、形成原因及影响因素，给出了缺陷形成过程的图解模型，提出了减少和消除缺陷的工艺措施。

At the same time,three dynamic models of cylinder powder green-preform are set up ,which are :die and corefixed on the die shoe , core moving with green-preform, core and die moving downwardin relation to green-preform. The theoretical equations of the green-preform densities andpressing stresses of the three pressing conditions are also derived.

同时建立了凹模与型芯固定在下模座、型芯随压坯一起运动和型芯与凹模相对于压坯向下运动等三种圆环形粉末压坯压制的力学模型，导出了这三种压制条件下的压坯密度与压制压力的理论公式；其结果能够指导粉末冶金模具设计，为发挥模具材料的潜力提供依据。

Because of the unique fitting mode of hydraulic drawing, early wrinkles of conical parts (very likely to wrinkle in ordinary deep drawing) fit orderly to punch under the action of counter pressure as the punch moves down ward, thus wrinkle-free parts can be obtained.

由于充液拉深方法独特的贴模方式，使普通拉深方法极易起皱的锥形件成形初期产生的皱随着凸模向下运动在对向液压的作用下顺次贴向凸模，从而可以得到无皱的零件。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了