异步电动机特性研究的(f、b、0)坐标法

采用 (f、b、0 )坐标法 ,推导出适用于分析异步电动机在变频调速时稳态特性的基本表达式。     

制度共识的异质发生学--政治秩序整合的社会基础分析

一定的社会基础决定着其所适用的政治秩序整合模式,整合模式变迁的合理性在于对由其社会基础所决定的潜在收益空间的释放,民主制作为一种高级整合模式,只适用于异质体社会。虽然民主与法治,更准确地说是民主基础上的法治,在思想形态上已经成为一种全球共识,也正是在这种西方现代明价值观的全球性扩张下,发展中国家面临着巨大的现代化压力。使这种思想共识演化为制度共识,对于发展中国家而言,重要的不是如何模仿发达国家的整合模式,而是如何促进本国社会的异质化进程,并在此基础上为制度共识的发生及稳定创造充分与必要的条件。     

单片机在电动机软起动中应用

近几年来,单片机已经被认为在现代文明和技术发展与进步中,起着越来越重要的作用;工业上,单片机技术有着广泛的应用,针对其应用的越来越广泛,提出了利用面向对象技术设计的方法,并将其用于以intel16位系列单片机8098为中央处理单元的电子软设计中;因为三相交流异步电动机启动电流过大,易烧毁或损坏电机,基于单片机系统、集成芯片和可控硅为辅助,提出了三相晶闸管交流调压的数字移相控制方法,通过控制触发角来控制输出电压,从而降低电动机的启动电流,使安全稳定的启动。这种方法具有其特点.即达到了延长异步电动机使用寿命的目的,具有故障显示及自诊断功能。     

MSI中规模计数器设计课程中的教法探讨

在数字电子技术课程的教学中有一章专门讨论时序逻辑电路的分析与设计,随着MSI中规模芯片的普及,大量的MSI计数器芯片进入了教材。由于课时的限制,教师不可能全面讲授这类芯片的设计方法,从而导致许多同学在考研时或在毕业后的工作中遇到不同的MSI芯片设计时就会出现困难。为此在本文中,我利用多年的教学经验总结归纳了此类问题的相关特征和简便的设计方法,为在校电子专业学习的同学们和从事电子专业教学的教师们提供一个参考。     

Possible factors influencing Asian students' degree of participation in peer-facilitated online discussion forums: a case study

This study investigated possible factors that might influence the degree of student participation in asynchronous online discussion forums. Degree of participation refers to the number of messages posted by the students. Data were collected from 41 forums, students' reflection logs, and students' interviews. Of these 41 forums, the top third forums (n = 14) in terms of the highest frequency of participant postings were identified. Fourteen less frequent forums were randomly chosen from the remaining forums. We also assessed the quality of the discussions found in both the more frequent and less frequent groups by examining the levels of knowledge construction exhibited in the online postings. We found that that the quality of contributions in the more frequent group was greater than those found in the less frequent group in terms of higher knowledge construction levels. Quantitative analyses showed that the duration of the discussion could not account for the difference between the two groups. Instead, the more and less frequent forums differed in terms of group size, as well as the frequency of two habits of mind displayed by the student facilitators: (a) is aware of own thinking, and (b) is accurate and seeks accuracy. Qualitative analyses of the reflection logs and interviews suggested several other important factors that could also influence students' decision to participate: (a) familiarity with the facilitator, (b) mutual obligation to help each other, (c) knowledge about the topic, and (d) availability of time. Implications of the findings and suggestions for future research are provided.     

基于交互关系的突发事件热度预测研究

突发事件之间存在的关联、削弱或衍生的关系,会对现发的突发事件的热度产生影响。本文根据突发事件的交互关系,建立舆情敏感信息库,对突发事件的热度进行预测,并通过实验验证和理论分析,为政府消解突发事件负面舆情提供参考。     

基于可满足性问题的有用工作量证明共识机制

为减少在公链上基于哈希的工作量证明中无意义计算消耗,合理利用区块链网络算力,创建一个促进可满足性问题（SAT）研究的有用工作社区环境,基于 SAT 问题求解,开发一种有用工作量证明共识机制,通过竞争解决困难 SAT 问题的方法获得区块链中区块构造权,并使各节点间达成共识。实验证明,基于该共识算法的区块链系统性能稳定,且各算法在系统中运行平稳,基于 SAT 求解的工作量证明共识机制有助于解决基于哈希计算工作量证明的无意义消耗问题,更好创造 SAT 问题的研究环境。     

Predicting Future Trends in Adult Fitness Using the Delphi Approach

Abstract

This study determined how experts see the future of adult fitness by using the Delphi Technique as a measurement tool. Experts (n = 50), all Fellows of the American College of Sports Medicine, were selected on the basis of their reputations in adult fitness. Three questionnaires were submitted to the panel. In the first questionnaire each expert listed five or more events, trends, or developments they thought would take place and five or more events they would like to see take place in the next 25 years. From the events and trends listed on this questionnaire, 100 items were generated that formed the basis for the last two questionnaires. Responses to the items on the second questionnaire were evaluated on a 5-point Likert scale for probability and desirability. In the third questionnaire, group means and standard deviations were calculated and recorded for each item. Only those items which were significantly (p < .01) higher than 3.0, the average probability or desirability response on the Likert scale, were included in the analysis. The items were divided into seven categories: fitness in sport and recreation, fitness and wellness, fitness in industry, fitness in education, fitness in business, research in fitness, and fitness equipment and facilities. The highest single mean for any item for both probability (M = 4.31) and desirability (M = 4.83) was increased awareness of health and fitness among the elderly.     

Interaction and cognitive engagement: An analysis of four asynchronous online discussions

Online discussion plays a unique role in face-to-face and distance teaching and learning. Interaction and student cognitive engagement during the online discussion are critical for constructing new understanding and knowledge. This article analyzes types of interaction that occur during online discussions, examines levels of student cognitive engagement in each discussion, and explores their effects on and implications for learning and teaching in higher education. By combining methods of social network analysis with qualitative content analysis, the article explores new methodologies for analyzing participation, interaction, and learning that take place online, and suggests areas for research in learning and teaching online.