A micro-perspective on students’ behavioral engagement in the context of teachers’ instructional support during seatwork: Sources of variability and the role of teacher adaptive support

Despite increased acknowledgement of the significance of situational factors to engagement, engagement is traditionally seen as a student characteristic. In this study, we investigated to what extent variation in observational measures of behavioral student engagement during seatwork is due to students versus teachers, teacher-student dyads, or situational (i.e., variation in time) effects. Additionally, we studied whether adaptive support during teacher-student interactions contributes to student engagement following that interaction. A cross-classified multilevel analysis of 324 video- and audio-recorded secondary school teacher-student interactions showed that situational factors and error were the strongest source of variability in student engagement. Other than expected, teacher-related and dyad-related variability were limited. Although behavioral engagement after teacher-student interaction was significantly higher than pre-interaction student engagement, higher post-interaction levels were not related to the level of adaptive support provided during the teacher-student interaction. These findings imply that situational factors deserve more attention in engagement research, for example by investigating what situational factors contribute to engagement. For teachers, the time-variant, situation-dependent nature of engagement opens up valuable opportunities to actively design optimal learning situations.     

交流异步电机状态变量观测及其优化控制

采用维持磁通始终恒定的方法对电机转矩直接控制，可解决交流异步电机控制精度和系统复杂性之间的矛盾，在电机状态变量观测及位置控制中应用了现代控制理论，和传统的矢量控制方法相比，在相同的性能指标下，该系统便于用微机来完成实时控制。     

Harnessing Yik Yak for Good: A Study of Students’ Anonymous Library Feedback

This study explores academic libraries’ potential uses of the mobile application Yik Yak, with particular focus on patrons’ anonymous feedback about library services and spaces. Over a 232-day period, the authors observed the Yik Yak feed for their university and recorded all yaks related to the library. A content analysis of the 249 library-related yaks found six distinct purposes that these library-related yaks served, from the perspective of the patron, which are of interest to the library: asking questions about library services; reporting problems with library spaces; reprimanding violations of and encouraging adherence to library policies; sharing compliments about library services; demons-trating need for improved library services; and discussing and offering feedback about library programs. This study reveals several opportunities for academic libraries to engage with Yik Yak in order to serve their patrons better, including providing virtual reference services, monitoring problems within the building, developing proactive approaches to policy enforce-ment, gathering honest and continuous feedback about the library's strengths, and identifying opportunities to improve and expand services. Implications for practice are discussed.     

论中学体育课程教学的健康达标

正确的健康概念，是指不仅没有疾病，而且表现在身体、心理和社会适应能力各方面保持良好状态，才能算得真正健康。因此，中学体育课程必须由发展学生运动能力，强调学生身体素质达标传统的技术观念，向三维健康观念转变，全面促进学生健康达标。     

光折变晶体三维存储的几种编码方式之比较

本文讨论了当今较为前沿的三维存储光折变晶体材料写入全息图的几种编码方式的基本原理，详细分析了它们的特点。     

中国画论视野中的油画创作教育

“外师造化,中得心源”是中国绘画理论审美意象创作的一种高度概括,是一个统一的过程。在这个过程中创造性的想象起着很重要的作用,中国当代化创造应对本国化有深入的了解,青年油画创作要不断地训练创造性的想象,为创造能够体现先进化发展方向的具有鲜明的民族特色、饱满的时代精神和真诚的个性创造的中国油画艺术而努力。     

数字电视及其先进应用

简要介绍了数字电视技术及其在多媒体数据广播和交互式电视中的应用。     

WEB环境下实验教学系统研究

针对网络教学中缺乏实验环节的问题,本文采用ASP、SQLServer和Java集成架构实现了web环境下机电系统的远程实验。利用该平台用户可以通过网络设计控制算法、调整远端机电系统的控制参数,实验运行结果和现场图像也可反馈给用户端。应用效果验证了该网络远程实验教学系统的有效性和可行性。     

土木工程施工立体化教学研究与实践

解读了土木工程施工立体化教学的内涵,详细论述了土木工程施工立体化教学改革研究内容及三个过程,实现了教材建设多样化、教学内容时代化、教学手段现代化,在教学实践中验证了教学效果。     

多孔尖晶石型锰钴氧化物的制备和催化性能

为获得高效催化还原对硝基苯酚的锰钴氧化物催化剂,以聚甲基丙烯酸甲酯为模板,采用硬模板法制备了具有三维有序大孔结构的尖晶石型锰钴氧化物(MnCo₂O₄)。运用X射线粉末衍射仪、全自动物理吸附仪、扫描电子显微镜及紫外-可见分光光度计等对催化剂的结构和形貌进行表征,并研究其对硼氢化钠还原对硝基苯酚反应的催化性能。结果表明,多孔MnCo₂O₄催化剂具有立方晶相结构,其三维有序大孔孔径均一,比表面积达到65.7 m²/g;与体相MnCo₂O₄和其他贵金属催化剂相比,多孔MnCo₂O₄催化剂表现出更优异的催化活性,对硝基苯酚还原的反应速率常数可达6.59×10^-2s^-1。多孔MnCo₂O₄催化剂在5次重复利用后对硝基苯酚的转化率仍高达90%以上。