Ag(I)-p-NBR-TritonX-100分光光度法测定微量银     

崔永春  张小曼  翟平  汤峨 《昆明师范高等专科学校学报》2002,24(4):58-59

研究了新试剂5-(p-硝基苄叉)若丹宁(p-NBR)与贵金属离子Ag(I)的显色反应,在pH=7.0的NH4Ac缓冲溶液介质中,TritonX-100存在下,Ag(I)与P-NBR生成1:2的黄色稳定络合物,λmax=400nm,ε=3.52×104L·mol-1·cm-1,银的含量在0～30μg/25mL范围内符合比尔定律.方法用于显影液及定影液中微量银的测定,结果满意.  相似文献   

用于电力系统故障电流限制器的快速合闸开关研究     

邹积岩  董恩源  陈金祥 《上海大学学报(英文版)》2002,6(1):92-96

This paper presents a new type of fault current limiter(FCL) based on fast-closing switch,which is composed of a capacitor bank and a reactor in series.The main control component is a fast-closing switch connected in parallel with the capactitors,which is drien by the electromagnetic repulsion force.It can response the order within 1 ms.When fault occurs,the switch closes and the capacitors are bypassed.and the fault current is limited by the reactor,Simulation analysis and experiment show that the electromagnetic repulsion force actuator can meet the demand of fast-closing switch,it is feasible to develop the FCL with low cost and high reliability.  相似文献   

The relation between teacher-set performance goals and students’ mathematical achievement     

《Studies in Educational Evaluation》2016

The relation between teacher-set performance goals for 361 individual students and these students’ mathematics achievement was investigated. High performance goals were found to strongly relate to student performance, with an effect size of d = 0.80. The performance goals were set by the teachers at the end of a step-by-step procedure, consisting of initial teacher expectations, the use of data, and team input. This procedure was expected to decrease negative expectancy bias. Higher teacher performance goals than teachers’ initial expectations, so-called positive changes, were positively associated with the performance of initially low achievers. Initially high achievers, for whom the teachers made a positive change, performed worse than comparable students for whom initial expectation and final goal were the same.  相似文献   

Why Do Cocks Crow? Children’s Concepts About Birds   总被引：1，自引：0，他引：1  

Pavol Prokop  Milan Kubiatko  Jana Fan&#;ovi&#;ová 《Research in Science Education》2007,37(4):393-405

Research into children’s ideas showed that children’s interpretations of natural phenomena often differ from those of scientists. The aim of our study was to identify children’s ideas of various age classes (7/8–14/15) about birds. A questionnaire with 31 multiple choice and open ended questions and eight photographs were administered to 495 children from 10 elementary schools in Slovakia. Children’s ideas were examined in six dimensions (bird classification, food, senses, communication, migration and breeding including parental care). We found several misconceptions, some of them with both anthropomorphical and teleological reasoning of the children about birds within each dimension. In general, misconceptions were more frequently found in younger children, but several misconceptions were similarly distributed across all age classes.  相似文献   

图Km,n∪Kp,q的算术性     

刘育兴  徐建平 《赣南师范学院学报》2008,29(3):38-40

两个偶图Km,n与Kp,q的并记作Km,n∪Kp,q.利用构造的方法,给出了图Km,n∪Kp,q的一个算术标号,证明了图Km,n∪Kp,q是（k,d）算术图,从而推广了路线等人的相应结果.  相似文献   

论我国财政投融资体系的改革和完善     

刘标胜 《江苏经贸职业技术学院学报》2007,(2)

根据新古典经济学及凯恩斯主义的观点和博弈论的分析方法,政府干预经济具有其必要性。在市场经济中,政府干预经济最有效的手段之一就是财政投融资。针对我国财政投融资刚刚起步,在体制、法律和运作方式等方面还存在很多不足的现状,研究借鉴发达国家的财政投融资运作模式,探讨我国财政投融资的发展方向、运作模式及相关法律制度建设,有助于完善我国的财政投融资体系。  相似文献   

Redesigning chat forum for critical thinking in a problem-based learning environment     

Akcell Chii-Chung Chiang  Isaac Pak-Wah Fung 《The Internet and Higher Education》2004,7(4):311-328

Support is needed to promote problem-based learning (PBL) and to enhance critical thinking skills in discussion-based Internet forums. By advancing the capabilities of chat room and forum software, problem-based discussions for learning can be supported further in online learning environments. In this paper, the authors report on MALESAbrain, an intelligent learning tool. The model is built on the notions of threshold and knowledge weight from the discipline of machine learning. The model encourages learners to judge or critically evaluate the solutions posted by others before exploring further knowledge content. The system then sums up the judgment scores as its knowledge weight to pass the thresholds setup for ranking/arranging the learning issues. This constraint design, therefore, becomes a mechanism for critical thinking in a problem-based learning activity. MALESAbrain as a model helps transform the forum and chat room into rich learning discussion environments.  相似文献   

道德需要是道德建设的前提     

韦兆钧 《河池学院学报》2003,23(1):18-21

本文从经济和道德的关系入手 ,提出实施公民道德建设首要解决的问题就是认识问题 ,即如何看待社会主义市场经济建设中的道德滑坡现象的本质 ;并通过对以往道德教育效果不佳进行归因分析 ,得出尊重和满足主体的道德需要是道德教育的切入点的结论  相似文献   

声目标识别技术研究   总被引：2，自引：0，他引：2  

吕永林 《楚雄师范学院学报》2008,23(3):24-31

本文对声目标识别的关键技术进行研究,探讨用小波分析来进行声信号处理和特征提取,用BP神经网络和支持向量机的模式分类方法来进行分类识别.通过对四种声信号的仿真实验表明,使用小波变换和人工神经网络技术及支持向量机分类技术相结合对声目标进行识别是有效、可行的.  相似文献   

多媒体与英语课堂教学     

黄田  郭建红  朱湘军 《邵阳学院学报(社会科学版)》2002,(3)

随着多媒体技术的不断成熟,计算机辅助教学在英语教学中的实际运用正受到越来越多的关注。文章概述了多媒体英语教学的诸多优点,从课件意识向积件思想的发展,阐述了第二代英语课堂教学的模式,并在硬件与软件两方面的规划上做了具体的尝试。  相似文献