幂格的理想与素理想

研究了幂格的理想和素理想,建立了格的理想与格上幂格的理想的一种联系,获得了格的理想(素理想)与它的商格的理想(素理想)之间的关系。     

格蕴涵代数的关联理想与模糊关联理想(英文)

本文提出了格蕴涵代数的关联理想和模糊关联理想的概念 ,讨论了它们的性质 ,指出了关联理想与理想、关联理想与关联滤子、关联理想与模糊关联理想、模糊关联理想与模糊关联滤子、模糊关联理想与模糊理想之间的关系     

平衡双重半拟补MS代数的理想和同余关系

在平衡双重半拟补MS代数上引入(*)理想,(+)理想,(°)理想和(*,+,°)理想的概念,探讨平衡双重半拟补MS代数上(*)理想,(+)理想,(°)理想和(*,+,°)理想与核理想的关系,获得了(°)理想是核理想的结论.同时构造出了以(*,+,°)理想为核的最小同余关系和最大同余关系,并获得了最小同余关系和最大同余关...     

有界Heyting代数的交换理想与关联理想

运用泛代数和格理论的方法和原理进一步深入研究有界Heyting代数的理想问题。在有界Heyting代数中引入了交换理想、关联理想和正关联理想概念并讨论了它们的性质和相互关系。获得了各种理想的若干等价刻画。证明了在有界Heyting代数中,关联理想和正关联理想等价;在Ockham型有界Heyting代数中,理想和交换理想等价。同时,给出了有界Heyting代数的交换理想成为关联理想的一个充分必要条件。     

正则剩余格上的模糊理想基

首先,在正则剩余格中引入模糊理想基的概念,介绍了模糊理想基的一些重要性质,并且利用这些性质,给出了模糊理想基的三种等价形式;其次,结合具体实例讨论了模糊理想基与模糊理想的关系;最后,给出由模糊集生成模糊理想基及由模糊理想基生成模糊理想的方法.     

Quantale代数及其代数理想

给出Quantale代数的概念,得到了单位Quantale是Quantale代数的充要条件,讨论了理想与代数理想的关系,找到了理想不是代数理想的具体例子以及理想是代数理想的充分条件.     

BCK-代数的Ω-模糊正定关联理想

给定一个集合Ω,引入了BCK-代数的Ω-模糊正定关联理想的概念,给出了一些恰当的例子,讨论了BCK-代数的Ω-模糊理想与Ω-模糊正定关联理想的关系.利用模糊正定关联理想,刻画了Ω-模糊正定关联理想.反之,模糊正定关联理想通过Ω-模糊正定关联理想来构造.证明了Ω-模糊正定关联理想(Ω-模糊理想)的同态原象仍是Ω-模糊理想(Ω-模糊理想).     

亚BCI-代数的模糊理想

引入了亚BCI-代数的模糊子代数、模糊理想、闭模糊理想和模糊P-理想的概念,研究了它们的性质。证明了模糊子代数(模糊理想、闭模糊理想、模糊P-理想)的同态像与同态原像仍能成为模糊子代数(模糊理想、闭模糊理想、模糊P-理想)。     

BCI代数的软关联理想和软正定关联理想

给出BCI代数的软关联理想和软正定关联理想的概念,讨论软理想、软关联理想和软正定关联理想三者之间的关系,研究了两个软关联理想(软正定关联理想)的扩展交、限制交、限制并和限制差分的性质。     

超理想的单子及其应用

在扩大模型下,用超理想的单子对超理想进行刻画;进而用它给出了理想为超理想的条件;最后给出理想的单子与超理想的单子之间的关系.     

GLOBAL FINITE ELEMENT NONLINEAR GALERKIN METHOD FOR THE PENALIZED NAVIER-STOKES EQUATIONS GLOBAL FINITE ELEMENT NONLINEAR GALERKIN METHOD FOR THE PENALIZED NAVIER-STOKES EQUATIONS

1. IntroductionIn the numerical simulation of the Navier-Stokes equations one encounters three seriousdifficulties in the case of large Reynolds numbers f the treatment of the incomPressibility con-dition divu = 0, the treatment of the noIilinear terms and the large time integration. For thetreatment of the incoInPressibility condition, one use the penalty method in the case of finiteelemellts [1--2l and for the treatmen of the noulinar terms and the large tfor integration, oneuse the nonlin…     

Rail-bridge coupling element of unequal lengths for analysing train-track-bridge interaction systems

This paper presents a rail-bridge coupling element of unequal lengths, in which the length of a bridge element is longer than that of a rail element, to investigate the dynamic problem of train-track-bridge interaction systems. The equation of motion in matrix form is given for a train-track-bridge interaction system with the proposed element. The first two numerical examples with two types of bridge models are chosen to illustrate the application of the proposed element. The results show that, for the same length of rail element, (1) the dynamic responses of train, track and bridge obtained by the proposed element are almost identical to those obtained by the rail-bridge coupling element of equal length, and (2) compared with the rail-bridge coupling element of equal length, the proposed element can help to save computer time. Furthermore, the influence of the length of rail element on the dynamic responses of rail is significant. However, the influence of the length of rail element on the dynamic responses of bridge is insignificant. Therefore, the proposed element with a shorter rail element and a longer bridge element may be adopted to study the dynamic responses of a train-track-bridge interaction system. The last numerical example is to investigate the effects of two types of track models on the dynamic responses of vehicle, rail and bridge. The results show that: (1) there are differences of the dynamic responses of vehicle, rail and bridge based on the single-layer and double-layer track models, (2) the maximum differences increase with the increase of the mass of sleeper, (3) the double-layer track model is more accurate.     

非正则条件下类Wilson元的构造及其应用

本文在非正则性条件下，研究了窄四边形上的类Wilson元。通过参考元上类Wilson元的构造，证明了由此产生的有限元对任意窄四边形剖分通过Irons分片检查，得到了二阶问题的误差估计。结果表明，该单元的收敛性质与Wilson元的类似。     

最佳等参元

等参元及其参数变换的插值方法。是有限元分析的有力工具之一,在工程计算中,得到广泛的应用. 在有限元分析中,当采用等参元时,一旦单元的等参坐标变换的Jacobi矩阵发生奇异,就要中止计算,下机修改原有的单元剖分,直到所有单元的Jacobi矩阵均非奇异. [1]突破原等参元的规定,给出了八节点Serendipity等参元的修改公式;[2]也给出了类似的修改公式.上述均以数值例子说明新公式的优点.而[3—6]完整、系统地给出     

半导体器件瞬态模拟的对称正定混合元方法

提出具有对称正定特性的混合元格式求解非稳态半导体器件瞬态模拟问题。提出一个最小二乘混合元方法、一个新的具有分裂和对称正定性质的混合元格式和一个解经典混合元方程的对称正定失窃工格式求解电场位势和电场强度方程;提出一个最小二乘混合元格式求解关于电子与空穴浓度的非稳态对流扩散方程,浓度函数和流函数被同时求解;采用标准的有限元方法求解热传导方程。建立了误差分析理论。     

Stability analysis of frame structures by bubble-function method

In the stability analysis of frame structures, the results by conventional finite element method (FEM) in which one member is taken as one element are sometimes unavailable. This paper took a new basic function system with bubble functions as the shape function of a bar element to develop a bubble function finite element method (BFEM), in which the bending and the geometric stiffness matrices were derived from the principle of virtual work. Bubble functions are finite element modes that are located entirely within a single element and are zero on boundaries of the element, but are nonzero at the other points. BFEM is as concise as conventional bar FEM but has better accuracy, and is adaptable to the buckling analysis of all kinds of frame structures. The use of bubble functions significantly improves the convergence of finite element analysis, and efficiently reduces the computation cost for the buckling analysis of frame structures. Numerical results show that using bubble functions in finite element for the stability analysis of structures is very efficient, especially for high-rise and large-scale frame structures.     

一种用于索结构分析的悬链线单元

根据弹性悬链线的理论解析解推导出适于索结构有限元分析的悬链线单元·与常用的三节点、五节点曲线单元相比,采用该单元编制的软件具有输入数据少、计算机时省、计算精度高的特点     

On Characterizations of Special Elements in Rings with Involution

Let $R$ be a ring with involution. It is well-known that an EP element in $R$ is a core invertible element, but the question when a core invertible element is an EP element, the authors answer in this paper. Several new characterizations of star-core, normal and Hermitian elements in $R$ are also presented.     

A quadrilateral plate bending element based on deformation modes

In this paper, a quadrilateral element is proposed for the analysis of thin plate bending. This element is non-conforming and consists of four-nodes and twelve degrees of freedom. A third-order field for the element displacement is written in terms of the deformation modes. Moreover, the rotational fields are obtained by utilizing the first-order Jacobean matrix. All interpolation functions are explicitly found by the presented formulation. The stiffness matrix of the element is then computed by using these functions. Finally, the accuracy of the suggested element is evaluated by solving some thin plate bending structures. Numerical findings reveal the new quadrilateral element MKQ12 is robust and accurate for analysis of thin plates.     

Quadratic nonconforming finite element method for 3D Stokes equations on cuboid meshes

In this paper, the quadratic nonconforming brick element(MSLK element) introduced in [10] is used for the 3D Stokes equations. The instability for the mixed element pair MSLK-P_1 is analyzed, where the vector-valued MSLK element approximates the velocity and the piecewise P_1 element approximates the pressure. As a cure, we adopt the piecewise P_1 macroelement to discretize the pressure instead of the standard piecewise P_1 element on cuboid meshes. This new pair is stable and the optimal error estimate is achieved. Numerical examples verify our theoretical analysis.