新型缝纫机用永磁直流电动机驱动电路设计

介绍一款缝纫机用永磁直流电动机驱动电路设计。该缝纫机具有良好的起动、调速和制动性能,通过脚踏板控制缝纫机即动即停。本驱动电路设计很好地解决了离合器电动机电能浪费的缺点,具有较好的应用价值。     

语篇衔接视角下的大学英语阅读教学(英文)

了解语篇的衔接与连贯有助于阅读理解能力的提高。以语篇衔接理论为支撑,构建衔接分析模式,通过对大学英语课文中语篇衔接手段尤其是词汇衔接的分析,探索一种新的教学模式,以帮助学生明确语篇线索、掌握语篇模式、推导语篇主旨。语篇衔接的讲解与训练可以作为阅读教学的一个重要组成部分,还可以被纳入自主学习策略培训课程中,这有助于学生自主学习能力的提高。     

试论全绝缘屏蔽铜管母线在变电站中的应用

介绍了一种新型的变电站设备——全绝缘屏蔽铜管母线,简述了其结构,概括了其优点和部分现场应用情况,分析了推广应用这一新设备的意义。     

高校设备档案管理存在的问题及对策

加强高校设备档案管理具有重要意义,设备档案管理中存在着诸多问题,针对这些问题应采取相应的解决对策。     

基于扭转振动装置的内模PID控制器设计

以扭转振动装置为研究对象,分析了其系统的组成结构,并且对于装置的数学模型进行了推导。简单介绍了内模PID控制器的原理,设计了控制器的参数,并进行了仿真实验,得到的仿真曲线证明了该控制器的有效性。     

瞳孔直径大小检测驾驶员疲劳的实证效度分析

驾驶员疲劳是指驾驶员在驾驶过程中,身体机能整体性的下降现象,它是导致交通事故的主要因素之一。因此,选取一种有效可靠的生理指标检测驾驶员的工作疲劳具有重要的实践意义。本研究采用驾驶员动态危险知觉视频量表加载工作负荷,诱发疲劳。使用自我报告法、眼动追踪与心电技术,测查39名驾驶员的疲劳状态。结果显示：采用瞳孔直径指标检测驾驶疲劳具有跨人群的一致性,随着驾驶员自我报告的困倦感增加,其瞳孔直径缩小,心率变异性减小,瞳孔直径与心率变异性呈显著正相关。说明随着工作时间的延长,驾驶员逐渐进入疲劳状态,瞳孔直径可以成为检测驾驶员心理疲劳的有效指标。     

钠与水反应的实验装置改进

高中化学教材中钠与水反应实验虽然简单,但无法让学生直观看到反应生成的气体,且未能对该气体性质进行论证即给出结论,不利于学生探究精神的培养;同时,该实验容易因取用钠太大造成实验事故。文章通过改进实验,能清楚观察到气体的生成并对其溶解性、可燃性进行验证,并能观察到钠在煤油和水层反应的跳动现象,效果明显,实验成功率100%,不存在安全问题。     

A longitudinal study on the uses of mobile tablet devices and changes in digital media literacy of young adults

This study examined whether gaining access to a new digital device enhanced the digital media literacy of young adults and what factors determine such change. Thirty-five young adults were given a mobile tablet device and observed for one year. Participants engaged in an online community, responding regularly to online surveys and discussion forums. Digital media literacy, using multidimensional scales, was measured at the beginning and end of the study. Usage was measured every month to track changes over time. When measured with multiple dimensional scales, the participants’ digital media literacy levels increased over time. Those who used the tablet device for information access and social activities increased their digital media literacy in some dimensions. However, an increase in digital media literacy was not directly related to the time spent on the tablet.     

Using action research to improve health and the work environment for 3500 municipal bus drivers

During the past five decades occupational researchers have documented that bus drivers’ health is worse than in almost any other profession. The authors suggest that the reason there has not been any successful attempt to change this situation is because the focus until now on removing statistically associated external risk factors has been too narrow. The article describes a project whose purpose was to improve the health and well‐being of 3500 Copenhagen bus drivers. At the end, more than 200 interventions were implemented. The authors adopted a new approach of combining epidemiological results and qualitative methodologies, creating a broader explanatory foundation for action, linked by repetitive processes of critical reflection, which was central to defining problems, explaining causes, developing sufficiently effective interventions and measuring effects. The project revealed the importance of several new and potentially preventable factors involving such issues as lifestyle, private stressors and inappropriate management. During the project period an evaluative framework was developed to explore and measure the complex effects of multiple interventions. Three years after the interventions were launched, follow‐ups revealed remarkable improvements such as reductions in stress and body pains, an increase in satisfaction, and improvements in management and the drivers’ cabin. This article is the story of a methodological journey, from classical epidemiology to an approach combining the strengths of survey (broad coverage), qualitative methods (in‐depth focus) followed by critical reflections and ending with action research.     

The use of keywords for delivering immediate performance feedback on teacher competence development

Literature shows that feedback that is specific, immediate and goal-oriented is effective on (pre-service) teachers’ performance. Synchronous coaching gives this kind of feedback. Due to immediateness of feedback, pre-service teachers can suffer from cognitive load. We propose a set of standardised keywords through which this performance feedback can be delivered – each keyword acts as a summary for the feedback message. The construction and the selection of the keywords is aimed at the reduction of message ambiguity, while at the same time a low level of cognitive load on the pre-service teacher must be maintained. An in vivo pilot-study with 40 respondents (pre-service teachers and their coaches) supported our hypothesis that usage of such sets of standardised keywords will mitigate the levels of ambiguity and cognitive load. These findings and other considerations for additional research using immediate performance are addressed.