Theoretical solution of a spherically isotrophic hollow sphere for dynamic thermoelastic problems

The separation of variables method was successfully, used to resolve the spherically symmetric dynamic thermoelastic problem for a spherically isotropic elastic hollow sphere. Use of the integral transform can be avoided by means of this method, which is also appropriate for an arbitrary thickness hollow sphere subjected to arbitrary thermal and mechanical loads. Numerical results are presented to show the dynamic stress responses in the uniformly heated hollow spheres. Project supported by the National Natural Science Foundation of China (Nos. 10172075, 10002016)     

Theoretical solution of a spherically isotropic hollowsphere for dynamic thermoelastic problems

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一类四阶两点边值问题对称正解的单调迭代法

利用单调算子的迭代方法,给出了一类四阶两点边值问题x(4)(t)+f(t,x(t))=0(0≤t≤1),x(0)=x’(0)=x(1)=x’(1)=0的对称正解.     

Analytical solution for electromagnetic scattering from a sphere of uniaxial left-handed material

INTRODUCTION The concept of left-handed materials (LHM for short, also called negative index materials) was in- troduced by Veselago (1968). An LHM has both negative permittivity and negative permeability, which makes the wave vector, the electric-field vector, and the magnetic-field vector in the LHM obey the left-hand rule. Experimental verifications for the existence of an LHM were made and its use as a perfect lens was suggested (Pendry, 2000; Shelby et al., 2001a; 2001b; Smith …     

位于介质锥公共顶点处电荷场的解法分析

镜像法和分离变量法是电动力学教学中的重要内容之一．学生通过学习,掌握镜像法和分离变量法对后续课程的学习有很大的帮助．文章用镜像法和分离变量法给出了位于介质锥公共顶点处电荷场的势。     

NTM方法在非线性贝叶斯动态模型中的应用

将NTM方法应用于非线性贝叶斯动态模型，给出了它的递推公式以及随机变量的数字特征的计算，与蒙特卡洛方法相比提高了效率和精度.     

3D analytical solution for a rotating transversely isotropic annular plate of functionally graded materials

The analytical solution for an annular plate rotating at a constant angular velocity is derived by means of direct displacement method from the elasticity equations for axisymmetric problems of functionally graded transversely isotropic media. The displacement components are assumed as a linear combination of certain explicit functions of the radial coordinate, with seven undetermined coefficients being functions of the axial coordinate z. Seven equations governing these z-dependent functions are derived and solved by a progressive integrating scheme. The present solution can be degenerated into the solution of a rotating isotropic functionally graded annular plate. The solution also can be degenerated into that for transversely isotropic or isotropic homogeneous materials. Finally, a special case is considered and the effect of the material gradient index on the elastic field is illustrated numerically.     

模糊变量函数计算的顶点方法研究

本文介绍了一种计算模糊变量函数的新方法———顶点方法。这种顶点方法可避免由于传统的区间分析方法对变量集合离散化或变量在函数表达式中多次出现而产生的异常发散。     

一类复变量优化问题的次梯度投影算法

利用CR微分理论,提出求解一类线性等式约束的复变量非光滑凸优化问题的复值次梯度投影算法（CSPM）,该算法能完全基于复域上运行。在较弱的条件下证明了算法的全局收敛性,数值实验进一步表明了CSPM的可行性和有效性,该算法尤其适合大规模优化问题的求解。     

集族存在唯一的相异代表系的一个必要条件

由集族的对称差给出了集族存在唯一的相异代表系的一个必要条件 ,揭示了集族的对称差与相异代表系之间的关系     

求解一类偏微分方程的边值问题的新方法

提出了一个新思路求解一类偏微分方程在空间W1,2 0（Ω）上的解。先在空间W1,2 0（Ω）上的规范正交系{φk}m k=1 构成的有限维子空间中构造出方程的近似解,并通过能量估计定理将近似解取极限得到弱解,最后证明弱解的存在唯一性,从而得出弱解即是方程在W1,2 0（Ω）上的通解。     

用等效图求解电容器电容的两类典型问题

应用等效图示的方法、分析求解平行板电容器插入电介质和加上屏蔽罩后的电容。     

用变量分离法求解分数阶微分方程

为了更好地描述在受反常扩散和非指数松弛方式控制的复杂系统里的运输动力,提出了扩散和Fokker-Planck类型的分数阶运动方程,而这些分数阶微分方程是从基本的随机行走模型里导出来的.文章将用变量分离法求解这两类分数阶运动方程.     

一类任意随机变数序列的强大数律

给出了一类任意随机变数序列的强大数律。     

Numerical approach for a system of second kind Volterra integral equations in magneto-electro-elastic dynamic problems

INTRODUCTION In scientific and engineering problems, Volterra integral equations are always encountered and have attracted much attention (Christopher and Baker, 1977; Delves and Mohamed, 1985; Brunner and van der Houwen, 1986; Kress, 1989; Oja and Saveljeva, 2002; Maleknejad and Shahrezaee, 2004; Maleknejad and Aghazadeh, 2005; Zerarka and Soukeur, 2005). Generally, exact solutions are very difficult to find and solutions have been obtained for only some few special cases (Yan and …     

一类条件最值的三角解法

给出在特定区域内的mx+ny及yx型函数最值的三角解法。     

旅游地规划空间组织的理论研究

旅游地作为一个旅游开发与经营管理的空间地域，其规划发展涉及到旅游地的空间区位和环境、旅游资源的空间分布格局与空间对比、旅游市场的空间拓展、旅游发展的空间总体布局、旅游项目的空间定位、旅游线路的组合设计、旅游基础设施和接待设施等空间配置的诸多方面。这些规划要素的空间组织是在区位论、核心一边缘理论、区域发展理论、比较优势理论等理论指导下，采取系统分析法、旅游竞合及协调共生分析法、ASEB栅格分析法等，进行空间整合和优化配置，形成旅游地发展的空间组织机理，促进旅游地的良性发展。     

三类一阶微分方程的求解公式

文献对三类一阶徽分方程的求解，采用先找积分因子，再利用积分因子转化为全微分方程，然后按全徽分方程的求解方法求解，其过程较繁复．本文借用变量替换法，化为变量可分离的方程，直接给出通解的积分形式，推广了方程的可积类型，并使求解过程大为简化．     

学前儿童科学教育目标模型的构建

教育目标指导和支配整个教育过程。学前儿童科学教育目标的确立至少要考虑3个方面－－儿童发展、社会需要、学科性质。即社会需要是学前儿童科学教育目标确立的客观依据；儿童的现实发展状况是学前儿童科学目标确立的发展心理学依据；学前儿童科学教育的学科特点和性质是制定学前儿童科学教育目标的重要依据；布卢姆等人的《教育目标分类学》以人的身心发展的整体结构为框架，为建构科学教育目标体系提供了一个比较规范化、清晰化的形式标准。以布卢姆教育目标分类标准为依据，以情感态度、认知能力、动作技巧这3个范畴确立学前儿童科学教育目标可以弥补以往课程目标单一的价值取向，从而构建出新的学前儿童科学教育目标的理论模型。     

A dynamic analysis of why learners develop a preference for autonomous learners in computer-mediated communication

A large number of studies in CMC have assessed how social interaction, processes and learning outcomes are intertwined. The present research explores how the degree of self-determination of learners, that is the motivational orientation of a learner, influences the communication and interaction patterns in an online Problem Based Learning environment. Given the complexity of CMC, we expected that autonomous learners would be more willing to contribute to cognitive discourse. In time, we expected that control-oriented learners would develop a preferential attachment to contribute to discourse from autonomous learners. Data were gathered from 37 autonomous and 39 control-oriented learners who posted 1669 messages. Using a dynamic multi-method approach of content analysis of cognitive and social discourse, social network analysis, and measures of academic motivation, we find some preliminary evidence that motivational orientation influences communication and social interaction patterns amongst learners. From the beginning, most control-oriented learners develop a preference to connect to and communicate with autonomous learners, although a separate team-analysis indicates that group dynamics also influence how learners develop connections with other learners in time. Our findings further the understanding of differences found in distance learning courses about participation and drop-out.