电磁调速电机控制器的设计     

史宏俊  莫岳平  朱肖陈  崔顺  雍才富 《林区教学》2016,(4):78-80

设计了一种以89C52RC单片机为核心,单闭环PI控制的电磁调速电机控制器。该控制器通过PI调节让单片机发出相应的PWM信号使电磁调速电机中的电流发生相应的变化,达到控制转速的目的。设计中采用单片机智能控制,实现了转速设定、转速显示、转速检测、转速恒定,掉电时保存数据等一系列功能。解决了模拟器件速度调节较为困难,硬件较为复杂,不能灵活控制等一系列问题。实现了1r/min—1 200r/min的调速范围,转速的精确度和可靠性都有了很大的提高,控制装置体积较小,携带更方便,值得推广使用。  相似文献   

Dialogue's Impact on the Quality of Relationships     

Caroline Seet  Ng Pak Tee 《Educational Research for Policy and Practice》2003,2(3):205-214

This paper presents the findings of an action research that examines teachers' perception of the quality of dialogue and how it impacts on the quality of relationships in a primary school in Singapore. The paper explores how school leaders can facilitate dialogue and also discusses the issues and factors that affect teachers' perception of dialogue. Analysis of the data obtained through a questionnaire and face-to-face interviews shows that the more favourable the perception of dialogue amongst teachers, the more favourable is their perception of the quality of relationships in the school. The implication for school leaders is that by developing a higher quality of dialogue, a better school climate is fostered. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

语法学研究的学科对象和语料对象     

刘顺 《江西师范大学学报(哲学社会科学版)》2003,36(2):125-128

语法学的研究对象可以分为学科对象和语料对象。学科对象应以句子为研究基点，任务是找出语法单位结构和功能的规律。语料对象是普通话，语法研究应该区分不同层次的普通话语料。例如，口语和书面语就应该分别进行研究，这样才能得出正确的结论。  相似文献   

努力创建学习型企业为企业发展提供智力支持     

孙文东 《武汉工程职业技术学院学报》2003,15(3):60-63

本文从烧结厂职工文化、技术状况等角度出发，论述了如何创建“学习型”企业和企业职工教育在国有企业中的地位与作用。为提高企业人力资本和企业创效回报率等方面取得显著成效。  相似文献   

电容近炸引信的综合参数测试系统     

程顺 《西江大学学报》2006,27(2):10-13

测试电容近炸引信的信号处理电路的动态性能参数，是产品研制、调试、生产的重要环节．利用计算机、信号调理板、数据采集板和在LabView平台上开发的软件，构成一套完整的电容近炸引信综合参数测试系统、该系统针对电容近炸引信的检波放大信号、积分信号、微分信号和启动信号等技术指标进行测试和分析。判断电路工作情况，分析有故障电路的故障原因．该系统具有测试精度高、开发成本低、检测效率高、操作简单等优点．  相似文献   

APPLICATION OF GENERALIZABILITY THEORY IN THE INVESTIGATION OF THE QUALITY OF JOURNAL WRITING IN MATHEMATICS     

Youyan  Shu Mei  Shun 《Studies in Educational Evaluation》2007,33(3-4):371-383

This study examined the use of generalizability theory to evaluate the quality of an alternative assessment (journal writing) in mathematics. Twenty-nine junior college students wrote journal tasks on the given topics and two raters marked the tasks using a scoring rubric, constituting a two-facet G-study design in which students were crossed with tasks and raters. The G coefficient was .76 and index of dependability was .72. The results showed that increasing the number of tasks had a larger effect on the G coefficient and index of dependability than increasing the number of raters. Implications for educational practices are discussed.  相似文献   

Counselor Educators’ Perceptions of and Experiences with International Students     

Kok-Mun Ng 《International journal for the advancement of counseling》2006,28(1):1-19

Thirty-six counselor educators’ perceptions and experiences with international student trainees were examined in this online survey research. Findings support the issues identified in the literature as confronting international students and also surface some issues specific to students in counselor training. International counselor education students tend to experience more difficulties in areas related to language, clinical training, adjustment, and cultural differences. Similarities and differences were also found within international student categories involving western and non-western countries and between international and domestic students. Counselor educators in general reported favorably on working with international students. Findings support attention being given to further examine the specific training and supervisory needs of international counseling students.Portions of this article were presented at the 2003 Southern Association of Counselor Education and Supervision Conference, Chattanooga, U.S.A. and at the 2004 American Counseling Association Convention, Kansas City, Missouri, U.S.A.  相似文献   

浅谈企业图书馆如何为精神文明建设服务     

孙继宏 《图书馆学研究》1999,(6):11-12

本文阐述了企业图书馆在精神文明建设中的重要作用,提出了加强为精神文明建设服务的五项措施.  相似文献   

高赖氨酸酵母菌的辐照选育     

孙雪雁  金世芳 《科技通报》1998,14(6):429-432

采用高能电子束辐照处理四株不同的酵母菌株 ,筛选赖氨酸含量较高的突变株并研究电子束对酵母的辐照效应 .试验表明 :电子束处理酵母的最佳剂量为 4 .14～ 4 .83k Gy,临界致死剂量为6.8k Gy,起始剂量为 0 .69k Gy,不同菌株对电子束的敏感性不同 ,其敏感性强度分别为产朊假丝酵母 >产香酵母 >热带假丝酵母 >面包酵母 .发酵试验表明 :不同剂量的电子束处理酵母 ,其胞外赖氨酸含量都发生不同程度的变异 ;其变异幅度为 84～ 2 90μg/ ml,经电子束处理的酵母其胞外赖氨酸含量比出发菌株赖氨酸含量平均提高 10 .9% .在剂量为 4 .83k Gy,致死率 80 %的条件下 ,酵母胞外赖氨酸变异幅度最广 ,产生高赖氨酸菌株的突变株比例为最大 ,达到 16.5% (胞外赖氨酸含量在 1.4 mg/ ml以上 ) ,在突变体选育方面具有较大的可选择性和可行性 ,为该菌的菌种改良提供了一条遗传育种的途径  相似文献   

Framing the Problem: effects of wording on children's statistical inferences     

Sik Hung Ng  Margaret‐Ellen Pipe  Bruce Beath  Derek Holton 《教育心理学》1999,19(4):489-499

ABSTRACT A total of 96 children aged 11 to 12 years were given statistical inference problems (base‐rate and law of large numbers) designed to test the effects of wording on their answers. The wording of the problems was manipulated to make the information on base‐rates and on the law of large numbers either more salient or less salient. The latter condition was established by adding extraneous information to base‐rates, or, in the case of the law of large numbers, making the context unfamiliar or focusing choice on a particular person rather than on the group. A significant main effect of wording was found across all problems in favour of the salient condition. The results indicated that the children had a high level of statistical intuition and that they knew when to reason statistically and when not to.  相似文献