查询词典 calculus of finite difference

This paper, which focused on the structure optimization theory and method, has finished such studies as follows: The three dimension model has been built, which provide the necessary conditions for the building of the dynamics equivalent model. By the launch dynamics simulation, the loads of the key joints when the rocket is launched has been got, which provide the necessary data for the finite element analysis and the structure optimization. The finite element model of the excess weight parts of the rocket has been built, buy the finite element intension analysis of the model in two conditions, the displacement and the stress of the key points have been got, which make us know the distributing of the stress and the transmogrification of the part. To satisfy the intension and the precision design request and to decrease the weight of the part as many as possible, the part has been topology optimized by the structure optimization theory and method. After that, the new model has been analysis in structure and launch dynamics. The contrast of the character change of the old part and the new part and the influence on the rocket system have been studied.

本文以结构优化理论和方法为核心，主要做了以下工作：建立了某自行火箭炮全炮三维实体模型，为建立该火箭炮系统的动力学等效模型提供了必要条件，进行了发射动力学仿真，得到该火箭炮发射装置各关键连接部位在发射状态下的载荷，为有限元分析和结构优化提供了必需的数据；建立了该火箭炮发射装置超重部分的有限元模型，分两种工况，对模型进行了有限元强度分析，得出了关键部位的位移和应力值，对其的应力和变形分布有了具体的了解；运用结构优化的理论和方法，对该火箭炮发射装置超重部分进行了拓扑优化，使其在满足强度和精度的要求下尽可能多地减轻重量，对优化后得到的模型进行了结构分析和发射动力学分析，对比了该部件优化前后的特性变化以及对火箭炮系统的影响。

Quadratic finite volume element method s for the air pollution model in one-dimensional;2. The two-grid algorithm of the finite volume element method for second-order indefinite elliptic problems;3. A fally discrete finite volume element method is given for one-dimensional two-phase incompressible flow in porous media.

在初始网格剖分上采取分段线性函数空间作为有限体积元方法的试探函数空间，在相应的对偶网格上采取分段常数函数空间作为其检验函数空间，对一维不可压缩两相渗流驱动问题提出了全离散有限体积元方法，并得到L2-模误差估计。

In this paper, the improvement of the low velocity impact resistance performance of composite plates using shape memory effect of shape memory alloy is analyzed by using finite element method, The constitutive relationship and the model of finite element analysis of SMA hybrid composite plates are established, The finite element equation is solved by using the Newmark direct integration method and the modified Hertzian contact law.

应用有限元方法分析了利用形状记忆合金的记忆特性提高复合材料抵抗低速冲击的能力，建立了SMA复合材料板的本构关系和有限元分析模型，利用修正的Hertzian接触定律确定冲击接触力，应用Newmark直接积分法求解方程；研究结果表明利用SMA的形状记忆功能可有效地改善复合材料板的低速冲击响应性能。

If totalization no longer has any meaning, it is not because the infinity of a field cannot be covered by a finite glance or a finite discourse, but because the nature of the field-that is, language and a finite language-excludes totalization.

替补性定量的这种分配——如果我们可以这么表达的话——为了使空闲的能指和它被用来瞄准的所指之间保持作为象征思维之前提条件的那种互补关系是绝对必要的。

According to practical work condition, section of a three segment hoist boom is self-determined with SECWRITE commands, then a finite element model is directly established in ANSYS environment with ANSYS finite element analysis software. Using Beam44 beam unit and node degree of freedom coupling technique to simulate connecting between each boom section and conduct finite element analysis, calculated result of stress deformation for the boom is obtained. The result from digital simulation is in relative coincidence with theoretical analytic result and the nonlinear decline occurrence in boom bending moment curve is explained.

以ANSYS有限元分析软件为工具，按吊臂实际工况，运用SECWRITE命令自定义三节吊臂截面直接在ANSYS环境下创建有限元模型，使用Beam44梁单元和节点自由度耦合技术模拟各节臂的连接，进行有限元分析，得到吊臂应力变形数值计算结果，数值模拟所得结果与理论解析解相吻合，解释吊臂弯矩图出现非线性下降的原因。

The main contents are as follows: Creating finite element model of cradle carriage, top carriage and trail of the howitzer. The structural static stress analysis of are dealt with finite element program system I-DEAS. For accuracy and computation cost, the nonlinear finite element structural dynamics model of the howitzer is created with different elements such as solid elements, shell elements and beam elements.

主要包括以下几个方面工作：建立了该炮摇架、上架和下架的三维有限元静力学模型，并应用I－DEAS有限元软件进行了强度分析；顾及计算准确性和计算成本，应用实体单元、壳单元和梁单元相结合的方法建立了该炮的非线性有限元结构动力学模型。

This paper makes a three-dimensional model for QCM and analyzes directly the coupled phenomenon of the structural and electric fields of QCM with finite element analysis software ANSYS10.0. Through analyzing the convergence of the resonant frequency of QCM, the correctness of the finite element analysis is proved. The influence of different sizes of electrode on vibration of QCM and an optimal size of electrode is discovered, namely thickness of 100 nm and radius of 3 mm. The design of mesa on crystal plate is provided to solve the problem that the energy trapping is not good enough. This design proves valid based on finite element calculation and an optimal size of the mesa is given, namely height of 9.8 μm.

基于有限元分析软件ANSYS10.0对石英晶体微天平进行三维建模，验证了建模的正确性，并对不同电极结构尺寸进行仿真计算，对出现的耦合情况进行了分析，通过实验结果对比，提出较佳电极尺寸结构为厚度100 nm，半径3 mm；为解决金电极能陷效应不够理想的问题，提出在晶片上下表面筑平台的设计，有限元计算结果表明此设计能改善电极区的能陷效应，并且较佳平台高度为9.8μm。

With a 586 computer and ALGOR FEAS software of finite element method, the static stresses of the equalizing bar are obtained by finite element analysis for three finite element models of beam, plate and brick element.

在微机586和ALGOR FEAS有限元软件环境下，对推土机平衡梁以梁、板、块单元为主分别建立了三种有限元模型和进行了有限元应力分析。

The paper gives stiffness matrix and mass matrix in finite element analysis of the ground vibration problem caused by track traffic by using three-dimension finite element method. Because three-dimension finite element analysis is very difficult, it is transmitted into a quadratic programming, which can be calculated by neural network.

本文融合神经网络技术和遗传算法，对轨道交通引起的地面振动进行了正分析和反演，并利用计算机技术实现了地面振动的三维动画模拟，这主要包括：(1)研究了压缩映射遗传算法，利用Banach空间的不动点定理证明了压缩映射遗传算法可以收敛到全局最优值，弥补了标准遗传算法不能收敛至全局最优值的不足。

It is found by solving the self-consistency equa tion that, at zero chemical potential and finite temperature the chiral phase transition is of second order, while both at finite temperature and density and at zero temperature finite density this transition is of first order.

通过求解序参量所满足的自洽方程，其结果表明：在零化学势有限温度情况下，有二级手征相变发生；对于有限温度和密度以及零温有限密度两种情况，手征相变为一级，并且其转变温度或密度与费米子所处的初始相有关，即从破缺相到正常相的转变温度或密度不同于从正常相到破缺相的转变温度或密度。

You can snipe the second and third union leaders from this position.

您可以鹬第二和第三工会领袖从这一立场出发。

Aiming at the currently shortage of XML streams quality detecting, this paper proposes a new forecasting method of XML streams quality by least squares support vector machines, which is used the method of XML keys' vector matrix as windows, and vector product wavelet transform to multilevel decompose and refactor the XML streams series, that can fulfill real-time checking demand of XML quality, and ensure constraint, consist- ency and integrality. For even more adapting net load, it proposes a control strategy by weight and adaptive adjustment to ensure XML streams quality.

针对当前XML数据流质量检测存在的不足，提出构建XML键的矢量矩阵作为窗口，利用矢量积小波变换多级分解与重构XML数据流，再结合最小二乘支持向量机对XML数据流质量进行预测的一种方法，满足XML数据流质量重构时实时检测的要求，保证XML数据的约束性、一致性与完整性；为了更好的适应网络负载，采取加权与自适应窗口调整等调度策略充分保证XML数据流的质量检测。