用磁流变液实现导磁材料机件表面的光整加工

磁流变液是未来应用最广泛的智能材料之一,它在无外加磁场作用下表现出良好的流体特性,在强磁场的作用下它的粘度会在毫秒级的时间内增加两个数量级以上,表现出类似固体的特性,一旦去掉磁场又立刻恢复液体的特性.这种可逆、迅速、易控的特点使磁流变液在机械工程中得到广泛的应用,其中包括表面光整加工,如将其用于光学镜片的表面研磨.目前其加工对象仅限于非导磁性材料,而现在绝大多数的机械零件的材料为导磁性材料.文章明确了磁流变液光整加工方法的主要优点;根据加工机理分析和初步实验研究,概括出将磁流变液用于导磁性材料表面光整时碰到的具体问题,并有针对性地提出了合理的解决方法.     

美术欣赏教学的"五字法"

美术欣赏，是一种审美情感的教育，它既能提高学生的审美能力，又能培养学生的创造精神，这种独特的教育功能早已被一些专家、学论证，然而，采取什么样的方法才能更有效地发挥其功能和作用呢?本从五个方面对美术欣赏教学的形式和方法进行了研究探索。     

高职学生行业英语自主学习能力动态研究

通过问卷调查和访谈,对高职学生的行业英语自主学习能力展开了动态考察,并基于教师和环境两个因素探讨了其变化的归因情况。两次问卷数据对比显示,学生的行业英语自主学习能力存在提升的趋势,教师因素和环境因素对学生的自主学习有促进作用。访谈结果表明,教师教学理念和教学方法的更新以及自习环境和实践环境的建设有助于学生行业英语自主学习能力的提升,具体体现在行业英语学习兴趣的提高、自主学习意识的提升以及自我效能感的强化等方面。由此可见,教师合理有效的介入和理想的学习环境是促进学习者自主学习的必要条件。     

Educational Research for Policy and Practice in Japan – With Particular Reference to Youth Education

Based upon the Fundamental Law of Education, Japanese school education system has long been a source of pride for the country as a result of the high school participation rate, the homogeneity of compulsory education throughout the country. However, the confidence of the people in its schools is now showing severe signs of strain and fatigue. In recent years, there have been many reports about the growing seriousness of a number of educational problems having to do with young people in their childhood and adolescence. Since the mid-1970s, a number of problems have been highlighted. They include violent behavior, juvenile crimes, bullying, refusal to attend school, dropping out at secondary level of education, and corporal punishment. Against the above background, based on recommendations from such advisory bodies as the Central Council for Education and the National Commission on Education Reform, the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) has adopted a range of policies and launched a series of educational reform programmes. For instance, what is called “Rainbow Plan”, based on the final report submitted by the National Commission on Education Reform, provides the country with basic guidelines for the educational reform in the near future. Roles of educational research for making policies have been of significance. Research initiated by the National Institute for Educational Policy Research (NIER) and the National Federation of Educational Policy Research Institutes (NFERI) is an example of contributions to the development of educational qualities in the country. This revised version was published online in July 2006 with corrections to the Cover Date.     

计算机辅助无机化学实验教学的研究

针对无机化学实验教学的特点和现状，研究了计算机辅助教学的作用和意义。介绍了课件的制作方法，并就无机化学实验教学中开展计算机辅助教学应注意的问题提出了一些见解。     

The relative impact of school‐wide positive behavior support on teachers’ perceptions of student behavior across schools,teachers, and students

School‐wide positive behavior support (SWPBS) is a systemic approach for implementing a proactive schoolwide discipline and for improving students’ academic and behavioral outcomes by targeting the school’s organizational and social culture. With a multilevel approach, the present study evaluates the relative effectiveness of SWPBS on teachers’ perceptions of the student behavior (N = 3,295) across schools, teachers, and children using a multilevel approach. We assessed teacher perception of student problem behavior five times during a 3‐year implementation of SWPBS in 23 Dutch schools. Multilevel analyses not only revealed a small increase in perceived prosocial behavior and a small decrease in problems with peers, but also different effects across children, teachers, and schools. Effects were stronger for girls and for students with higher severity of perceived problems at baseline. At teachers’ level, higher mean baseline severity of perceived problems was associated with the reduced impact of SWPBS on perceived emotional problems and problems with peers. At the school level, effects were stronger for regular schools as compared with special needs schools.     

学前教育对青少年成就发展的影响——基于CEPS数据的实证研究

基于中国人民大学提供的中国教育追踪调查数据,采用倾向得分匹配法,实证检验学前教育经历对青少年成就发展的现实影响,讨论“去小学”化的现实必要性。结果发现:接受学前教育和未接受学前教育的青少年在学业表现、家庭特征与个体特征等方面存在着一定的差异;Logit模型发现了家庭人力资本存量、经济资本以及家庭规模均对学前教育参与率的提升起到积极影响,但农村青少年的学前教育参与率相对于城镇要低2.3个百分点,显示出学前教育资源在城乡间的非均衡分布;倾向得分匹配法揭示了学前教育经历对青少年的学业表现具有正向影响,尤其是对语文和数学成绩的促进作用最为明显,但提前接触小学教育内容并不能帮助青少年赢在起跑线上。     

胺碘酮、心律平对犬缺血M细胞电生理的影响

目的:临床试验表明,Ⅰ类抗心律失常药物虽能抑制心肌梗塞病人的室性心律失常,但增加死亡率,而胺碘酮(Ⅲ类药物)可提高心肌缺血患者的生存率.心室中层肌细胞(M细胞)有其独特的电生理特性并在心律失常发生中起重要作用.方法:采用细胞内玻璃微电极技术,用含胺碘硐或心律平的模拟缺血液灌流M细胞,了解在缺血情况下,两种药物分别对M细胞电生理有何影响.结果:(1)犬左心室M细胞的动作电位呈现出与心外膜层肌细胞相似的峰-谷-穹窿(spike and dome)形态;动作电位时程(APD)随基础起搏周长(BCL)延长而明显延长,即频率依赖性.(2)模拟缺血使M细胞的静息电位(RP)除极、动作电位幅值(APA)和Vmax减小、APD缩短,其APD的频率依赖性减弱或消失.(3)胺碘硐可延缓或减轻缺血引起的电生理变化.(4)心律平明显抑制M细胞的Vmax、APA,并随频率加快而作用增强.进一步加重了缺血引起的动作电位参数的改变,并可造成传导延缓或阻滞.结论:胺碘酮可减轻而心律平则加重缺血引起的M细胞的电生理改变.部分地解释了上述临床试验的结果.     

Dynamic modelling and robust current control of wind-turbine driven DFIG during external AC voltage dip

INTRODUCTION Due to concerns about emissions from fossil fuels and the depletion of fossil fuel resources, re- newable energy systems are becoming a topic of great interest and investment in the world. In particular, wind energy has been the subject of much recent research and development. In order to overcome the problems associated with fixed-speed wind-turbine system and to maximize the wind energy capture, many new wind farms will employ wind turbines based on Doubly-Fed Induction Ge…     

Optical encryption with cascaded fractional wavelet transforms

INTRODUCTION Recently, with the development of science andtechnology, more and more people become interestedin researching image encryption techniques. Manymethods have been proposed for optical image en-cryption. Random phase encoding methods and digi-tal holography techniques are effectively used inencrypting (Javidi and Nomura, 2000; Unnikrishnanet al., 2000a; Hennelly and Sheridan, 2003; Nishchalet al., 2004). Meantime some important properties oflight are used to realize encryptio…