社会不公信息网络传播的社会反响特征及启示

社会不公信息会影响个体的社会认知和行为表现。网络跟帖是网民现实反应在网络状态中的一种呈现,分析网络跟帖内容,有助于探求不公信息传播的社会反响特征和信息素养培育的方法。从天涯、搜狐、腾讯三大网站,择取反映社会不公的报道的跟帖进行内容分析,可看出网民接触社会不公信息在情绪、认知特征及行为取向上的特点。应该通过学生、政府、传媒、老师合力培育学生的信息素养,减少社会不公信息传播的负面影响。     

Reductive cyclodimerization of arylmethylidenemalononitriles promoted by samarium and catalytic amount of iodine: facile synthesis of cyclopentene derivatives

INTRODUCTION Carbon-carbon bond formation is the essence of organic synthesis and the reductive dimerization of carbonyl derivatives by means of active metals is one of the most valuable methods for establishing carbon-carbon bonds. The reported reductive cyclo- dimerization of a,b-unsaturated nitriles provides novel access to functionalized five-membered ring products (Fan and Zhang, 2001; Zhong and Zhang, 2000; Zhou and Zhang, 1997; 1998). The products of enamine comprise important s…     

Reductive cyclodimerization of arylmethylidenemalononitriles promoted by samarium and catalytic amount of iodine: facile synthesis of cyclopentene derivatives

Samarium and a catalytic amount of iodine were used to obtain functionalized cyclopentenes by reductive dimerization followed by intramolecular cyclization of 1,1-dicyanoalkenes under mild conditions. Preject (No. 20072033) supported by the National Natural Science Foundation of China, and Zhejiang Provincial Natural Science Foundation of China     

金属材料学课程教学探讨

提高金属材料学课程教学质量,夯实学生的专业知识与技能,一直是该门课程教学面临的难题。本文就该课程教学进行了探讨并揭示讲授绪论时需要激发学生的学习热情,讲授合金化理论内容时需要进一步与前期专业基础课程《材料科学基础》和《固态相变》课程中的知识点相结合,同时该课程教学过程中需要开设一定的课带实验,有助于学生掌握抽象的专业理论与技能。此外,引导学生利用现代信息技术了解金属材料学最新研究发展动态。     

二针法测量梯形螺纹中径

研究一种测量梯形螺纹中径的二针测量法，与传统的三针测量法相比，具有能测量大直径螺纹和对操作空间适应性强等优点．该方法也适用于普通螺纹。     

“木马”检测软件

本文重点介绍运用Socket端口扫描技术，判断端口是否打开；接着关联端口和进程名，找到打开端口的进程名，并依据木马的一些基本特征检测出系统中的木马。而系统中的端口数量巨大，为了提高扫描速度节约时间，采用VC^ 的多线程，把多线程和端口扫描融合在一起，进行多线程端口扫描。实验表明，本系统在扫描速度方面有较优。越的性能。     

让个性飞扬,让特色彰显——初中作文指导方法初探

作文是语文教学的最高表现形式。提高学生的作文水平，必须要求学生注重平时作文材料的积累，在个性、特色上做文章。     

Socio-cognitive dynamics of knowledge building in the work of 9- and 10-year-olds

This study examines four months of online discourse of 22 Grade 4 students engaged in efforts to advance their understanding of optics. Their work is part of a school-wide knowledge building initiative, the essence of which is giving students collective responsibility for idea improvement. This goal is supported by software—Knowledge Forum—designed to provide a public and collaborative space for continual improvement of ideas. A new analytic tool—inquiry threads—was developed to analyze the discourse used by these students as they worked in this environment. Data analyses focus on four knowledge building principles: idea improvement; real ideas, authentic problems (involving concrete/empirical and abstract/conceptual artifacts); community knowledge (knowledge constructed for the benefit of the community as a whole); and constructive use of authoritative sources. Results indicate that these young students generated theories and explanation-seeking questions, designed experiments to produce real-world empirical data to support their theories, located and introduced expert resources, revised ideas, and responded to problems and ideas that emerged as community knowledge evolved. Advances were reflected in progress in refining ideas and evidence of growth of knowledge for the community as a whole. Design strategies and challenges for collective idea improvement are discussed.

A note on the analysis of metal threads

Abstract

The present work demonstrates by means of two practical examples the extreme importance of examination of cross sections of metal threads to obtain an overview of their structure and of the different materials employed in their manufacture. Problems that might be caused by disturbance of surface features during polishing were prevented by covering the sample before embedding with a layer of nickel, using electroless deposition. Results from scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) showed that, although the mean chemical composition of both metal wires is the same, their metallurgical structure is completely different: one consisting of pure silver with inclusions of copper particles and the other a silver–copper alloy.     

Effects of Cooperative Learning on Students’ Understanding of Metallic Bonding

The present study focused on investigating the effectiveness of instruction via newly developed teaching materials based on cooperative learning when compared to a traditional approach, on ninth grade students’ understanding of metallic bonding. Fifty-seven ninth grade science students from two science classes in the same high school participated in this study. The same teacher taught metallic bonding with cooperative learning to an experimental group (N = 28) and with a traditional teacher centred approach to a control group (N = 29). Students’ conceptual understanding of metallic bonding was measured using the Metallic Bonding Concept Test. The results from the Student’s t test indicated that the mean score of the students in the experimental group was significantly higher in the experimental group (78.60, SD = 8.62), than in the control group (54.33, SD = 9.11) after treatment. In the light of the results from the concept test and individual interviews, the misconceptions related to metallic bonding were found less in the experimental group than traditional. Five of these misconceptions were firstly identified in this study. The individual interviews which were done with students from experimental group immediately after the instruction showed that students had positive perceptions about their cooperative work experiences.