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Spectral element methods for partial differencial equation is introduced in this study from viewpoint of the collocation approximation of Chebyshev polynomial. Wave Equation and its space discretization are deduced. Two time integral methods, central difference method and implicit Newmark method, are introduced, and their stability and applicability are also discussed in some details. The significance of absorbing boundary conditions in spectral element methods for Aeroacoustics is explained, and Clayton-Engquist-Majda absorbing boundary conditions is emphasized and introduced, then the discrete scheme of this boundary conditions is deduced and applied to spectral element methods for wave equation.

本文从Chebyshev多项式逼近理论出发，详细介绍了谱元方法求解偏微分方程的过程；推导了流体中的声波动方程并在空间上对其进行了谱元离散；详细讨论了两种时间积分方法──中心差分法和Newmark方法，分析了它们的稳定性条件，并从理论上对比了两种方法的优缺点和适用范围；将吸收边界条件推广应用于谱元方法求解气动声学问题中，重点介绍了Clayton-Engquist-Majda吸收边界条件的原理和公式，推导了该吸收边界条件的变分形式，并将其引入波动方程的离散形式中。

The ultrastructural changes during the development of sieve element companion cell complex (SE/CC complex) in Populus deltoides were investigated using electronic microscopy. The result showed that SE and CC tome from the same secondary phloem mother cell. The development of sieve element went through three stages, i. e. immature, mature, and degenerate stage. In immature stages the sieve element presented radial expansion, cell wall thickening, and production of sieve plastid and P-protein. The cytoplasma selectivly autolysed in mature stage. At the same time, karyoplasm was dispersed, and nuclear envelope was not clear, or karyoplasm was disorgnized, and nuclear envelope was clear. The karyopalsm finally turned into P-protein. In degenerate stage, the cytoplasm completely disappeared, and the function was lost.

利用电镜技术研究美洲黑杨次生韧皮部筛管和伴胞发育过程中细胞超微结构的动态变化，观察到筛管和伴胞由同一个次生韧皮部衍生细胞分裂分化形成筛管约发育历经未成熟期、成熟期和衰退期的变化未成熟期筛管分子表现为细胞的径向扩展、壁的增厚、筛管质体和P-蛋白质的产生；成熟期筛管分子细胞组分发生选择性自溶，细胞核核质弥散状，核膜不清晰，或核膜清晰而核物质降解，最后细胞核完全解体转化为P-蛋白质类的物质；衰退期筛管分子细胞质完全解体消失，失去功能。

Firstly, the fully discrete standard finite element Galerkin method and the nonlinear finite element Galerkin method and the modified finite element Galerkin method in which time is discretized by the Euler implicit difference scheme are considered, and the - and - global relative errors and CPU time corresponding to the SG method, the NG method and the MNG method are computed respectively.

首先，对于全离散(时间离散是欧拉显式格式)标准有限元Galerkin方法和非线性有限元Galerkin方法以及修正有限元非线性Galerkin方法，分别进行数值计算，并比较了三种算法的计算解与精确解的误差估计及所耗费的CPU时间，结果验证了MNG方法要优于NG方法，而NG方法又优于SG方法。

The abundance and occurrence state of an element shows its difference in affinity and could provide important information for the geochemistry system and for the behaviors of an element in the system. The occurrences states of Pt and Pd in the parental rocks and in the fluid inclusions of the Western Guizhou Province basalt are studied. The result of this study shows the importance of determing the occurrence state of an element using its affinity, revealing that the PGE can be used in studying the migration and enrichment of elements in syngenetic fluid of the basalts.

对黔西基性玄武岩原岩与流体包体中Pt、Pd的赋存状态进行研究，结果说明了利用元素亲合性对指导其赋存状态查定的重要性，同时表明了研究该地区玄武岩中同生流体包体中铂族元素对重演古流体中元素迁移与富集具有重要的理论与实际意义。

Shadow effect can not be neglected for thermal analysis of spacecraft,Accroding to the angle between solar light and antenna orbit plane and its orbit location,analytical geometry method was used for accurately calculating solar radiation heat flux distribution of reflector surfaces.To analyze the temperature field under heat flux,the formulations of net radiation flux density between two gray elements and the net flux density of gray surface under external thermal flux were deduced.Based on the characteristic of space environment,the nonlinear temperature distribution in transverse direction of reflector shell self radiation were considered,the finite element formulations were given for orthogonal material layered shell by Galerkin method.A layered element including a inner heat source layer was proposed,and the finite element formulation expressed by DOF of the inner heat source layer were put forward with temperature and heat flux boundarys between adjacent layer.

单馈反射面赋形天线是未来星载天线发展的一个重要形式，分析了基于物理光学、几何光学和几何绕射理论的理想反射面辐射场；介绍了基于几何光学的反射面天线赋形方法；针对赋形过程中辐射场的快速分析要求，比较分析了基于物理光学的Fourier-Bessel和Jacobi-Bessel级数展开方法以及GB展开分析方法；利用GB展开快速分析方法在20GHz频率下对0.6m口径的天线进行赋形分析，实现中国大陆的30dB增益覆盖，通过数值计算研究了固定增益期望下的口径尺寸随频率的变化，以及频率为20GHz的不同尺寸天线赋形后的覆盖目标区域最大增益的变化情况。

Two special cases are discussed: flow due to a constant pressure gradient and flow due to a periodic one; In chapter 4, on the basis of the method of fractional element proposed by Schiessel et al and of the generalized fractional element networks proposed by Xu and Tan and by the use of discretization method for solving the inverse Laplace transform, we obtain the creep compliance of Zener and Poynting-Thomson models which are composed of the generalized fractional element networks.

并讨论了如下两种特殊情形：常压力梯度下的流动和周期性压力梯度下的流动；第四章在Schiessel等提出的分数阶单元法和徐明瑜等提出的广义分数阶单元网络的基础上，应用离散求逆Laplace变换的方法，给出并讨论了广义分数阶单元网络Zener和Poynting-Thomson模型的蠕变柔量。

Positive relationship was found between the bound cantharidin and Ca element in Mylabris and Epicauta, and between the bound cantharidin and Mg element in Mylabris, but negative relationship was found between the bound canthaiidin and Mg element in Epicauta.

斑芫菁属和豆芫菁属昆虫中的结合斑蝥素含量与钙元素呈正相关，斑芫菁属中结合斑蝥素含量与镁元素呈正相关，而豆芫菁属中结合斑蝥素含量与镁元素呈负相关。

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。

Usually, distribution networks operate in arborescence mode, so in the simulation of fault analysis the impact of faulty switch element on system reliability is apportioned to failure consequences of adjacent sections that connect to switch, and then an equivalent analytical model considering switch fault is proposed. Thus, not having to conduct the reliability analysis of switch element singly, the impact of switch element fault on system reliability can be calculated. Applying the proposed algorithm in RBTS-BDS6 system, RBTS-BUS4 system and actual medium-voltage distribution network to conduct reliability assessment, the results show that the proposed algorithm is superior in speed and possesses efficiency and engineering practicality.

配电网常具有树状运行特点，在故障解析模拟时，将开关元件故障对系统可靠性的影响分摊到连接开关的相邻分块的故障后果中，进而提出计及开关故障的可靠性等值解析模型，不需单独进行开关元件故障的可靠性分析即可计算其对系统可靠性的影响，应用该算法对RBTS-BUS6和RBTS-BUS4系统及实际中压配电网进行了可靠性评估，结果表明该算法有较明显的速度优势，具有高效性和工程实用性。

Productivity is formed by all element, among them science and technology is in controlled position, science and technology is the first productivity, the development level of science and technology, deciding the quality of the worker of the most active element ── in productivity directly, from this and the change that causes other element.

生产力是由诸要素构成的，其中科学技术处于支配的地位，科学技术是第一生产力，科学技术的发展水平，直接决定着生产力中最活跃的因素──劳动者的素质，由此而引起其它因素的变化。

The French are not suggesting a new EU treaty, but they have plenty of other wheezes.

法国人并不是在建议签署一个新的欧盟条约，但他们有许多其他的阴谋。

This letter was written by my brother.

这封信是我弟弟写的。