电子技术基础实验演示仪的研究与设计

电子技术基础课是高等学校理科类学生广泛选修的课程,实验课不少,但缺乏配套的课堂实验演示仪。文章主要是提出设计出实用性较强又简单便携的电子技术基础课堂演示实验用的演示仪,阐述了设计的原则,并给出其中一个演示仪电路设计的实例。     

2013—2017年教育部高等学校大学物理课程教学指导委员会成立暨第一次工作会议纪要

教育部高等学校大学物理课程教学指导委员会(简称:教指委)成立暨第一次工作会议于2013年7月9日至11日在同济大学举行.参加会议的有本届委员37名,上一届委员和顾问等12位,中国物理学会教学委员会副主任、清华大学吴念乐教授专程到会,并对本届教指委的成立表示祝贺.高等教育出版社、科学出版社、机械工业出版社、电子工业出版社、清华大学出版社和同济     

Static analysis of ultra-thin beams based on a semi-continuum model

A linear semi-continuum model with discrete atomic layers in the thickness direction was developed to investigate the bending behaviors of ultra-thin beams with nanoscale thickness.The theoretical results show that the deflection of an ultra-thin beam may be enhanced or reduced due to different relaxation coefficients.If the relaxation coefficient is greater/less than one,the deflection of micro/nano-scale structures is enhanced/reduced in comparison with macro-scale structures.So,two opposite types of size-dependent behaviors are observed and they are mainly caused by the relaxation coefficients.Comparisons with the classical continuum model,exact nonlocal stress model and finite element model (FEM) verify the validity of the present semi-continuum model.In particular,an explanation is proposed in the debate whether the bending stiffness of a micro/nano-scale beam should be greater or weaker as compared with the macro-scale structures.The characteristics of bending stiffness are proved to be associated with the relaxation coefficients.     

Analytical solutions to edge effect of composite laminates based on symplectic dual system

In the symplectic space composed of the original variables, displacements, and their dual variables, stresses, the symplectic solution for the composite laminates based on the Pipes-Pagano model is established in this paper. In contrast to the traditional technique using only one kind of variables, the symplectic dual variables include displacement components as well as stress components. Therefore, the compatibility conditions of displacement and stress at interfaces can be formulated simultaneously. After being introduced into the symplectic dual system, the uniform schemes, such as the separation of variables and symplectic eigenfunction expansion method, can be implemented conveniently to analyze composite laminate problems. An analytical solution for the free edge effect of composite laminates is obtained, showing the effectiveness of the symplectic dual method in analyzing composite laminates.     

基础力学课程考试改革应充分反映课程的教学要求

通过对现行基础力学课程考试中存在的问题和近年来基础力学考试改革现状的分析, 根据基础力学课程内容多、课时多、修课人数多的特点, 提出了基础力学考试改革的新理念 和操作方法, 指出基础力学考试改革应充分反映课程 的教学要求, 而且应有利于对课程教与学的良性促进.     

Diagonal form fast multipole boundary element method for 2D acoustic problems based on Burton-Miller boundary integral equation formulation and its applications

This paper describes formulation and implementation of the fast multipole boundary element method (FMBEM) for 2D acoustic problems. The kernel function expansion theory is summarized, and four building blocks of the FMBEM are described in details. They are moment calculation, moment to moment translation, moment to local translation, and local to local translation. A data structure for the quad-tree construction is proposed which can facilitate implementation. An analytical moment expression is derived, which is more accurate, stable, and efficient than direct numerical computation. Numerical examples are presented to demonstrate the accuracy and efficiency of the FMBEM, and radiation of a 2D vibration rail mode is simulated using the FMBEM.     

Precise large deviations for a customer-based individual risk model

In this paper,we propose a customer-based individual risk model,in which potential claims by customers are described as i.i.d.heavy-tailed random variables,but different insurance policy holders are allowed to have different probabilities to make actual claims.Some precise large deviation results for the prospective-loss process are derived under certain mild assumptions,with emphasis on the case of heavy-tailed distribution function class ERV(extended regular variation).Lundberg type limiting results on the finite time ruin probabilities are also investigated.     

Gr\"{o}bner-Shirshov Basis of Quantum Group of Type $\mathbb{D}_4$

The authors take all isomorphism classes of indecomposable representations as new generators, and obtain all skew-commutators between these generators by using the Ringel-Hall algebra method. Then they prove that the set of these skew-commutators is a Gröbner-Shirshov basis for quantum group of type \(\mathbb{D}_4\).     

先讲概率后讲计数原理的几点认识

新课标教材对于概率部分的教学内容采用先介绍概率,后介绍计数原理的方式,使得用惯了老教材的一些教师非常不适应.笔者认为,这种编排方式不单纯是必修与选修内容安排的需要,更重要的是符合学生的认知规律,有助于培养和发展学生的数学能力.     

2011年上海高考第14题探讨

上海高考题具有重在基础、强在能力的特点,基础题到底,能力题到位,难度泾渭分明.选填题的第14题,解答题的第22、23题通常作为压轴题,重在考查学生的应变能力和扎实的基本功.2011