查询词典 adjunction of an identity element

Then, taking the wave problems governed by the Helmholtz equation as an example, several conventional infinite elements such as the Bettess element, the Astley element and the Burnett element are compared and reviewed.

首先介绍无限单元的概念和无限元方法的特点；围绕求解以Helmholtz方程控制的波动问题，评述几种常规无限单元的优劣，这些单元包括Bettess元、Astley元和Burnett元。

The former, such as Bettess element and Astley element, needs geometry mapping and shape functions in terms of local coordinates, while for the latter, the shape functions are directly expressed in terms of global coordinates. This paper reviews the state-of-the-art and recent advances of the infinite element method for unbounded domains.

无限元分为映射无限元和非映射无限元：映射无限元需要引入几何映射，在局部坐标系中构造插值形状函数，如Bettess 元和Astley元；非映射无限元则直接在整体坐标系中构造插值形状函数，如Burnett元。

This paper presents the concept of structure basic element, structure variable element and the structure variable element design method.

从产品整个生命周期的产品数据模型分析入手，结合结构设计本身的特点，对结构设计的产品数据建模进行了研究。

Variable structure element design method was established, and basic structure element and variable structure element were defined.

本文以液压支架设计为背景，采用结构设计原型和基于原型的设计方法解决瓶颈问题，对结构设计、基于原型的设计方法和实现工具进行了深入的研究，主要工作如下： 1。

A comparative study of the bilinear, biquadratic quadrilateral element and quadratic triangular element for solving incompressible viscous flows was presented. These elements make use of the Galerkin/Least squares stabilized finite element formulation, in which the pressures and velocities are interpolated with the equal orders.

本文比较了用于求解不可压缩粘性流的四边形双线性、双二次单元及三角形二次单元的性能，这些单元采用GLS稳定化有限元格式，而压力和速度采用等阶数插值。

In chapter 2,all kinds of numerical methods of computational fracturemechanics are summarized,the development histories and present situation ofboundary collocation method,boundary integral method,finite difference method,boundary element method and finite element method are expounded,and theapplication of finite element method in fracture mechanics are emphaticallydiscussed.

第二章 总结了计算断裂力学中各种数值方法，论述了边界配位法、边界积分法、有限差分法、边界元法及有限元法的发展历史和现状，并着重讨论了有限元法在断裂力学中的应用。

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。

Maximum model values are found for the channel matrix Hi of each user and for each column vector of the matrix, position information of the matrix is transmitted to a transmitting terminal, the transmitting terminal reconstructs the amplitude of each element of the column vector after receiving the position information, and phase position is quantized, wherein, after reconstruction, the amplitude of the element with the maximum model value is larger than that of other elements of the column vector, and a quantized angle of the element with the maximum model value is smaller than that of the other elements of the column vector; c.

对每个用户的信道矩阵Hi，对该矩阵的每个列向量，找出其最大模值，将其位置信息发送给发射端，发射端收到后对该列向量各元素的幅度进行重构，相位进行量化，其中最大模值的元素重构后其幅度大于该列向量其余元素的幅度，其量化角度小于该列向量其余元素的量化角度；c。

Finite element method is used to build up element stiffness matrix and element mass matrix. After the combined total stiffness matrix and the total mass matrix are obtained.

采用有限元法建立不同管道元件的单元刚度矩阵和单元质量矩阵，最终形成管道结构的总刚度矩阵和总质量矩阵。

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。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。