双调谐回路负阻放大器的最大平坦特性

在微波放大器的谐振腔中引入双调谐腔回路是实现宽带微波及毫米波负阻放大器的有效方法。在推导出了该电路的稳态工作方程之后,着重讨论了实现最大平坦增益特性的条件,指出两谐振腔负载Q值的比值是实现最大平坦增益的决定因素,导出了获得最大平坦增益时,电路参数的解析表达式,从而为最大平坦增益设计提供了理论依据,研究的理论得到了以往文献中实验结果的验证。     

一类中立型泛函微分方程解的振动定理

给出了二阶中立型泛函微分方程,其中Pi（t）∈C（[t_0,∞）,[0,∞））,τ_i＞0（i＝1,2…,m）,f（t,u）∈C（[t_0,∞）×R,R）且f（t,0）＝0,g（t,v）∈C（[t_0,∞）×R,R）且的一切解均为振动的必要和充分条件。     

关于《一阶超前类型微分方程解的振动性》的注记

讨论了微分方程ｙ′（ｔ） ＝ ｑ（ｔ）ｙ（σ（ｔ）） ,σ（ｔ） ＞ ｔ,ｔ ≥ｔ０ 解的振动性,获得了其解振动的几个充分条件,从而改进了文献［２］ 中的相应结果．     

具有变系数的三阶中立型时滞差分方程解的振动性

本文研究具有变系数的三阶中立型时滞差分方程解的振动性,给出了其有界解振动的二个充分条件。     

半导体激光器的高频响应特性研究

应用一种新的半导体激光器理论模型—微波等效电路模型来研究半导体激光器的高频响应特性,得出半导体激光器高频响应特性与偏置电流的关系以及各电路参数对高频响应特性的影响,提出了提高半导体激光器高频响应的途径。     

关于时变大系統之平稳振蕩

本文利用大系统分解理论来研究时变大系统之平稳振荡问题。首先通过构造一个特殊的函数,将一个微分大系统的有界性问题转化为一个代数不等的求解问题,由此得出用期解之存在性。然后,由上极限理论对大系统之非常稳定性进行研究,由此导出周期之唯一性。     

关于电磁感应定律的两种表述

电磁感应定律有两种表述:一种是通量法则;另一种则把感应电动势分成感生电动势和动生电动势两部分。两种表述是否等效,是国内外多年争论而至今尚未解决的问题。争论的焦点是通量法则是否例外。本文通过对两种表述式的内在联系和讨论中经常使用的反例,比较全面而认真的分析,证明了两种表述式对任何闭合回路都完全等效,因此,通量法则没有例外。     

Crisis and public intellectuals: From the transnational intellectual field to the digital global public circuit

We examine the modes of intervention of global public intellectuals at times of crisis. In critical situations, public intellectuals take positions on matters that affect the societies they inhabit and, eventually, all humanity. To this end, they take advantage of the opportunities afforded by new communications technologies, establishing an important distinction between the “analog” intellectual (who relies on the slow time of books, opinion columns, and bookstores) and the “digital” intellectual who uses modern information and communications technologies. To study the activities of global public intellectuals and their political influence, we propose to leave aside the notion of “transnational intellectual field” in favor of an understanding of a transnational intellectual stage peopled by a certain type of intellectual agent whose symbolic and cultural production is disseminated through a digital global public circuit. To illustrate the functioning of a circuit of this type, we take the example of the Project Syndicate platform.     

Robotic assembly of printed circuit boards with component feeder location consideration

The use of industrial robots for the assembly of printed circuit boards (PCB) is fast gaining popularity. Minimization of the time required for board assembly while maintaining production quality is the process planner's main task. This task involves the specification of the insertion sequence of components in their respective locations and the assignment of component types to feeders or dispensing magazine slots. The time taken by a robot to fetch a component for insertion is dependent on the location of the feeder that holds the component type. Similarly, board assembly lime is dependent on the order of component insertion on the board and the fetch time of components between insertions. In this paper, models to minimize the total assembly time for a board are developed and studied. Factors considered in the analysis of the assembly time are the component assignment to magazine     

加强学习,努力提高试卷命题水平——电路分析基础课程2004年度考试卷分析

电路分析基础是电子电气工程类一门重要的专业基础课程,学生学好该课程对其后续课程学习有很大的影响。目前考试是测试学生理解电路水平的一个重要手段。随着电子技术的发展,教学内容、方法和手段不断发生变化,因此考试的内容和方式也应该不断改革,教师命题的水平也需要不断提高。本文介绍了电子科技大学2004年度电路分析基础课程的试卷,从全校2857份试卷中随机抽查了147份试卷,重点分析了计算题部分。其统计结果可以反映学生对知识点的理解和综合能力,也为教学的改进和试卷的命题水平提高提供一个参考思路和建议。