大学英语四、六级统考笔试“新”题型补充

根据社会发展对大学英语教学的要求、根据对大学英语和英语专业英语教学大纲、考试大纲、历年四、六级试题以及现行大学英语和英语专业英语教材的研究,本文提出了大学英语四、六级统考可以补充的六种题型,期望能在更大限度上实现四、六级考试大纲所描述的各项测试目的,提高四、六级考试的效度,并通过测试的反拨作用更好地引导大学英语教学向《大学英语教学大纲》提出的培养目标靠近。尽管有些题型对目前的大学英语学生有些超前,但社会发展对大学英语教学与测试的要求会让它们有用武之地。     

直流电机调速系统的工程设计方法的探讨

本文在“电子调节器优化”分析的基础上，全面讨论了直流电机调速系统的工程设计方法，为电机调速系统优化设计提供亍理论依据．     

Student Group Project Work: A Pioneering Experiment in Interactive Engagement

Fully half of the curriculum of Roskilde University, Denmark(RUC), is student-driven group research project work, often interdisciplinary. I shall describe the practice of group project work in the sciences at RUC, and evaluate implications for educational practice in the U.S.     

茶叶香气成分的研究--乌龙茶与鲜茶香气成分的比较

报道了用同时蒸馏-萃取装置分别提取乌龙茶与鲜茶香气成分，测得乌龙茶的香气成分含量为3．65％．鲜茶的香气成分含量为2．40%。用GC／MS法分别从乌龙茶与鲜茶香气成分中分离并确定出42种和19种化学成分，并对香气化学成分及含量进行了对比。     

Will I succeed in middle school? A longitudinal analysis of self-efficacy in school transitions in relation to goal structures and engagement

The current study aimed to explore the concept of transition self-efficacy, which is defined as individuals’ subjective evaluation of their ability to execute the actions required for a successful transition from elementary to middle school. The study followed a sample of 128 sixth-grade students for 2 consecutive years (before and after the school transition). A path analysis based on structural equation modelling revealed that the students’ perceptions of the teachers’ emphasis on mastery goal orientations predicted academic and social aspects of self-efficacy. The social aspect of self-efficacy in turn predicted changes in the students’ emotional and behavioural engagement after the transition. The results were robust when we controlled for self-reported GPA and gender. An interaction between gender and aspects of self-efficacy was also observed. The findings emphasise the importance of transition self-efficacy for adaptive school transitions and provide evidence that teachers’ goal emphases play a significant role in promoting self-efficacy.     

Learning and engagement through natural history museums*

This review examines how natural history museums (NHMs) can enhance learning and engagement in science, particularly for school-age students. First, we describe the learning potential of informal science learning institutions in general, then we focus on NHMs. We review the possible benefits of interactions between schools and NHMs, and the potential for NHMs to teach about challenging issues such as evolution and climate change and to use digital technologies to augment more traditional artefacts. We conclude that NHMs can provide students with new knowledge and perspectives, with impacts that can last for years. Through visits and their on-line presence, NHMs can help students see science in ways that the school classroom rarely can, with opportunities to meet scientists, explore whole topic exhibitions, engage with interactive displays and employ digital technologies both in situ and to support learning in the school science classroom. Although these interactions have the potential to foster positive cognitive, affective and social outcomes for students, there is a lack of reliable measures of the impact of NHM experiences for students. Opportunities to foster relationships between NHM staff and teachers through professional development can help articulate shared goals to support students’ learning and engagement.     

The role of perceived classroom goal structures,self-efficacy,and engagement in student science achievement

Background: Numerous studies have been conducted to investigate the factors related to science achievement. In these studies, the classroom goal structure perceptions, engagement, and self-efficacy of the students have emerged as important factors to be examined in relation to students’ science achievement.

Purpose: This study examines the relationships between classroom goal structure perception variables (motivating tasks, autonomy support, and mastery evaluation), engagement (behavioral, emotional, cognitive, and agentic engagement), self-efficacy, and science achievement.

Sample: The study participants included 744 seventh-grade students from 9 public schools in two districts of Gaziantep in Turkey.

Design and methods: Data were collected through the administration of four instruments: Survey of Classroom Goals Structures, Engagement Questionnaire, Motivated Strategies for Learning Questionnaire, and Science Achievement Test. The obtained data were subjected to path analysis to test the proposed model.

Results: Students’ perceptions of classroom goal structures (i.e. motivating tasks, autonomy support, and mastery evaluation) were found to be significant predictors of their self-efficacy. Autonomy support was observed to be positively linked to all aspects of engagement, while motivating tasks were found to be related only to cognitive engagement. In addition, mastery evaluation was shown to be positively linked to engagement variables, except for cognitive engagement, and self-efficacy and engagement (i.e. behavioral, emotional, and cognitive engagement) were observed to be significant predictors of science achievement. Finally, results revealed reciprocal relations among engagement variables, except for agentic engagement.

Conclusions: Students who perceive mastery goal structures tend to show higher levels of engagement and self-efficacy in science classes. The study found that students who have high self-efficacy and who are behaviorally, emotionally, and cognitively engaged are more successful in science classes. Accordingly, it is recommended that science teachers utilize inquiry-based and hands-on science activities in science classes and focus on the personal improvement of the students. Furthermore, it is also recommended that they provide students with opportunities to make their own choices and decisions and to control their own actions in science classes.     

温度监测的应用设计与编程

介绍了目前常用的三种温度监测电路,应用设计与编程,并举例说明。同时给出了与单片机80C196KB的接口及采用PL/M-96编写的程序。     

ANALYSIS OF MICROWAVE N-PORT NETWORK BY A MODIFIED BOUNDARY ELEMENT METHOD

A new approach based on resonance technique and modified boundary ele-ment method is presented to calculate the impedance parameter matrix of a microwaveN-port network of waveguide structure.A two port network is taken as a numerical ex-ample and the results show that the approach occupys the advantages of high accuracyand less computation effort.     

Psychologic implications of the maltreated-child syndrome

A retrospective investigation of 97 psychologically maltreated children showed a clear relationship between clinical symptoms and the intensity of the abuse. Parental neglect resulted in impairment of intellectual and locomotor development and emotional and behavioral disorders. Neurotic manifestations of regressive type appeared in nearly half the preadolescents who suffered severe psychological abuse. Children under 6 years of age presented functional symptoms, including regression in toilet training and sleep disorders secondary to inadequate mothering.