类比方法在磁路教学中的应用

本文从学生熟悉的电场和电路的一些基本概念出发,采用类比的教学方法逐一引出对磁场和磁路的一些基本概念的学习和理解,并介绍了如何在掌握基本概念的基础上进一步用类比方法学习磁路的基本定律,最后总结为一个直观的表格,帮助学生学习和理解磁路及其它相关知识.     

Some Classroom Uses of Ambits in Teaching Graph Theory

To a student in linear graph theory, many concepts which later become almost second nature often need at first step-by-step, concrete demonstrations. For example, cut sets and cut vertices become increasingly meaningful if the student is given a procedure whereby he, by himself, can correctly and confidently identify all cut sets and cut vertices in any given graph no matter how complex. For this purpose, an earlier definition of ambits is extended to provide the basis for a combinatorial method for finding all cut sets and cut vertices of a connected graph. As by-products, interesting properties of ambits are disclosed.     

电磁理论中的Hodge星算子

在三维空间中给Ｈｏｄｇｅ星算子下了定义，导出了０～３－形式基的星运算公式，指出了欧几里得空间中１－形式电磁量间的外积构成一个李代数．并导出了微分流形中的格林定理。     

Computer-Managed Instruction in Electromagnetic Field Theory

This paper discusses the application of computer-managed instructional techniques in an introductory electromagnetic field theory course being taught to all undergraduate students in the College of Engineering at The University of Iowa. In the process of preparing the various computer lessons, we found ourselves faced first with the need to carefully appraise what we wished the students to learn and then to consider appropriate teaching strategies for achieving the desired objectives. Our approach to computer assisted instruction takes several different forms, including use of drill and practice modules, tutorial segments, computer-administered quizzes, and field visualization through interactive computer graphics. Our computer-managed instructional materials complement the more traditional forms of instruction being used in EM theory, rather than replacing them. In this way we seek to provide alternatives designed to suit the different learning needs of our students.     

A Pitfall in the Scalar Electromagnetic Formulation of Kirchhoff Theory

A difficulty in applying scalar Kirchhoff diffraction theory to the individual components of the vector electromagnetic field is pointed out. For example, the method, if applied incorrectly, does not account for the cross-polarized radiation from a circumferential slot on a cylindrical structure.     

An Electromagnetic Teaching Aid

This paper describes a magnetic flux density measuring device (BMD) which is a helpful teaching aid in the study of the fundamentals of electricity and magnetism. The relatively low cost of construction and the simplicity of design should appeal to the university professor who wishes to ilustrate the principles of electromagnetic interaction with a demonstration, but is limited budgetwise and time-wise. The device is actualy used in calculating the force on a current carrying conductor in a magnetic field. Further algebraic manipulations yield the data for plotting a B-H magnetization curve for the ferromagnetic material used in the core. In an attempt to make the information given more readily useful, an example of the experimental procedure used at the University of Southwestern Louisiana is included. Part I describes the procedure for obtaining the data for plotting the B-H curve. Part I illustrates the quantities which determine the direction of the force on a current carrying conductor in a magnetic field and the property of residual magnetism. To reduce the somewhat time-consuming routine calculations required to obtain the data for plotting the B-H curve, a sample digital computer program is included which will perfonn this task.     

Electromagnetic Theory: A Simplified Representation

An outline of electromagnetic theory is presented in which extraneous concepts (principally the permittivity and permeability of free space) are eliminated and all analogies between electrostatics and magnetostatics are heightened. The result is a simplified representation in which the introduction of D and H is logically deferred until materials are introduced, with the need for their introduction then clearly revealed. All four field vectors E, D, B, and H have the same units and dimensions, a simplification which will aid the student. Maxwell's equations assume a cleaner, more symmetrical form, and other commonly used quantities are simplified, e.g., the impedance of free space is dimensionless and has a value of unity. Charge and current require redefinition, and conversion formulas between this proposed new system and MKS rationalized units are tabulated.     

基于双向电磁力加载的管件电磁翻边理论与实验

为克服传统单一径向电磁力翻边过程中翻边角度难以达到90°的缺陷,该文提出一种基于轴-径双向电磁力加载模式的电磁翻边系统来改善管件的翻边效果.仿真数据表明,与仅有径向线圈的电磁翻边系统相比,双向电磁力翻边系统中引入的强轴向电磁力在很大程度上增强了材料的轴向流动,进而提升了翻边角.此外,基于特定的铝管(AA6061-O)进...     

关于电磁场数值分析的若干认识

对电磁场数值分析这门学科的现状和发展，谈了一点看法，指出了目前存在的几个不利于学科发展的因素，探讨了当前应重视的问题和今后的研究方向。     

电磁屏蔽理论在电力电子设备中的工程化

介绍了电磁屏蔽原理与屏蔽体的效能计算公式,阐述了不同材料的电磁屏蔽特性,并在此基础上给出了电力电子设备中电磁屏蔽设计的各种具体办法以及应注意的问题.     

Unified Theory of Electromagnetic Induction and Magnetic Resonant Coupling

The difference between electromagnetic induction and magnetic resonant coupling was pointed out in the first proposal of electromagnetic resonant coupling. However, there was no clear technical comparison between the two methods. Therefore, in this study, five circuits are compared by using a phasor diagram, which is a basic and well‐known method in electric circuit theory. The transition from typical electromagnetic induction to magnetic resonant coupling is shown. The mechanism of the high efficiency and high‐power transfer across a large air gap and displacement is discussed, where the primary‐ and secondary‐side resonant frequencies are the same. From the above discussion, we conclude that when the specific conditions of electromagnetic induction are satisfied, the wireless power transfer can be categorized as electromagnetic resonant coupling. The unified theory of electromagnetic induction and magnetic resonant coupling is verified through experiment.     

实例教学法在“电磁场与电磁波”教学中的应用

本文针对"电磁场与电磁波"课程的特点,在教学中引入了实例教学法,分析了运用实例教学法的几个实例,探讨了运用实例教学法时的注意事项。实践表明,实例教学法作为一种启发式的教学方法,突出了学生的主体地位,有利于调动学生学习的积极性和主动性,能有效地培养学生理论联系实际的能力。     

浅议我国电力市场改革中的若干理论问题

对我国电力市场改革中需要研究的几个理论问题进行了简要分析。这些问题包括 :电力市场运营模式 ,电力市场交易 ,电能成本分析 ,电价理论 ,电力市场监管 ,电力市场技术支持系统 ,电力市场转运服务等。     

将科研内容融入"电磁场与电磁波"课程教学

在"电磁场与电磁波"的课程教学中,有机地增加科研内容不仅使学生对抽象的内容有新的认识,激发学生的求知欲,充分认识电磁场与电磁波理论的重要性,同时还能使学生掌握科研方法,为本科毕业论文的设计打下坚实的基础.本文以电磁场与电磁波教学中均匀平面波垂直投射到多层介质中内容为例,结合自己的科研工作,引入具有周期性多层介质结构的一维光子晶体内容,分别运用Rsoft软件模拟和Matlab编程计算一维光子晶体的性能,从而有利于学生理解多层介质结构的应用,提高教学的广度和深度.     

New Considerations in Teaching Switching Theory

In this paper some aspects of the relation between the state of the art and the way of teaching in the field of switching theory are described. Some critical comments and suggestions concerning the contemporary way of teaching switching theory are presented.     

语篇衔接理论在英语教学中的应用

语篇衔接理论是进行语篇分析的重要手段.衔接方式包括语法衔接和词汇衔接两个方面.将衔接理论应用于英语阅读教学、写作教学和翻译教学有很强的可行性和有效性,是丰誊教学手段、提高教学效果的一条新途径.     

归因理论在教学实践中的应用

本文对韦纳的归因理论进行了概述,指出教师可将归因理论应用于教学实践,研究学生的归因倾向,引导学生进行正确归因,激发其学习动机,使其逐渐走向成功.     

图式理论在金融英语教学中的运用策略

图式理论的发展和完善为金融英语教学提供了理论基础,在金融英语教学中发挥了积极的指导作用.本文试探性地以图式理论为依据,阐述了图式理论在金融英语教学中运用的策略,以有效地改进教学,提高教学质量,满足培养复合型人才的要求.     

"电磁场理论"课程教学方法的探讨

通过对"电磁场理论"教学方法的探讨,从多角度分析本课程各章节内容的衔接及与本课程其他相关专业、知识的联系,寻求比较适合电气工程及其自动化专业学生的电磁场理论教学方法,以培养学生使用基于场的观点对电气工程领域中电磁现象、电磁过程及电磁规律进行定性与判断的初步能力,并使其掌握对典型工程电磁场问题进行定量分析的基本技能.