带式输送机软启动技术的分析

根据带式输送机启动特性,对软启动过程进行了分析,着重介绍了CST启动装置的性能及其特点。     

Validity and reliability of a low-cost dynamometer to assess maximal isometric strength of upper limb

Muscle imbalance and deficit are key parameters for guiding rehabilitation and sports sessions and avoiding injuries. However, the high cost and non-portable nature of most instruments employed for muscle strength assessment frequently hamper an affordable evaluation in field conditions. This study evaluated the validity and reliability of a low-cost digital dynamometer to assess the maximal isometric strength of upper limb muscles. Fourteen physically active volunteers performed the main movements of the upper limb at maximal isometric strength: flexion-extension, internal-external rotation and abduction-adduction of the shoulder; and flexion-extension of both elbow and wrist. Validity was examined by comparing the strength values from the low-cost digital dynamometer and those measured by an isokinetic dynamometer, assumed as the gold standard. The correlation between both devices was perfect (r > 0.913), while Bland-Altman plots showed absolute agreement between both devices, the maximum range of the values of bias was ?0.99–1.00 N in wrist extension. Inter-tester and intra-tester reliability were excellent for all movements (ICC ≥ 0.855). The low-cost digital dynamometer showed strong validity and excellent reliability in assessing maximal isometric strength during the main movements of the upper limb. Professionals may use it for an affordable isometric muscle strength assessment in field situations.     

职业教育的概念与内涵

“职业”是人类生活的外在表现,这些活动因其结果而让个人感到有意义;“技术”的五个层面的含义、三种存在状态只是认识论中的“技术”,“技术”知识只有进入教育场域成为可传授的知识,才能成为“职业技术教育”场域中的“技术”知识。教育立场中“技术”知识的内在构成包括三个不可分割的组成部分：符号标准、逻辑形式和意义性。因此,职业教育是以“职业”和“技术”知识再生产为中介的人的价值的实现过程。     

智能电器定时控制电路的设计

本文设计了一个定时电子钟,目的是可以在设定的时间启动和停止。设计的主题思想是通过石英晶体振荡器产生的时标信号送到分频器,分频电路将时标信号分成每秒一次的方波信号。秒信号送入计数器进行计数,同时把累计的结果以"时"、"分"、"秒"的数字通过LED显示出来。到了设定的时间,接触器动作,开关闭合,就起到了定时的作用,来达到给电器定时的目的。     

Leader-following consensus for multi-agent systems with actuator faults via adaptive event-triggered control

In this paper, the leader-following consensus problem is investigated by event-triggered control for multi-agent systems subject to time-varying actuator faults. Firstly, for a case of the leader without control input, a distributed event-triggered fault-tolerant protocol is proposed with the help of adaptive gains. Secondly, the proposed protocol is developed by an auxiliary nonlinear function to compensate the effect of the leader’s unknown bounded input. It is shown that under the both obtained protocols the tracking errors converge to an adjustable neighborhood around the origin, meanwhile the Zeno behavior is avoided. Moreover, the protocols are fully distributed in sense that any global information associated with the network is no longer utilized. Finally, numerical examples are presented to show the validity of the obtained protocols.     

Teachers’ dilemmatic decision-making: reconciling coexisting policies of increased student retention and performance

In recent years, many countries within the Organisation for Economic Co-operation and Development have formulated educational policies aimed at providing better education to more students. However, this may be perceived as constituting dilemmatic spaces, where teachers must make efforts to reconcile coexisting political demands in their everyday work. The purpose of this article is to provide insight into how teachers handle coexisting educational policies of increased student retention and performance. Empirical findings from a one-year field study at a Danish vocational school explore how teachers’ decision-making as response to coexisting demands of increased student retention and performance involves the development of various pedagogical approaches to the students: an active ‘caring’ approach, a passive ‘wait until this class is over’ approach, an active ‘vocational gate-keeping’ approach, and a passive ‘wait and see whether they drop out’ approach. Based on the findings, it is argued that the various pedagogical approaches are developed through social negotiations with leaders, students, and other teachers. Moreover, these pedagogical approaches lead to the development of further negotiated, dilemmatic decisions to be made. Thus, a dynamic approach to teachers’ dilemmatic decision-making is proposed.     

“互联网+”背景下大学生心理健康教育的“心”路径

文章针对高校心理健康教育课程教学设置学时少,无法满足大学生心理健康持续发展的“心”需要的问题,讨论了如何充分发挥新媒体的功能与特性,使新媒体能够成为大学生心理健康教育的“心”出路,开启网络心理健康教育的“心”时代。     

知识获取、路径依赖对企业创新能力的影响研究

构建知识获取、路径依赖、渐进式创新和突破式创新之间的关系模型,运用SPSS和LISREL软件对收集的248份有效问卷进行实证分析。研究结果表明,中国企业的创新路径为知识获取-渐进式创新-突破式创新,知识获取对渐进式创新具有显著的影响,而对突破式创新的直接影响不显著;同时路径依赖对知识获取与企业渐进式创新之间的关系具有显著的调节作用。这为我国企业通过获取外部信息培育和发展创新能力提供了新的证据和启示。     

人文信息的多媒体声音实现方法探讨*

本文根据大千世界中声音的各种表现特征, 探讨了人文信息多媒体系统中声音信息的采样与传播机理及实现方法。