The Cosmos in a Cabinet: Performance,Politics, and Mechanical Philosophy in Henry Bridges’ ‘Microcosm’

How did ordinary people – artisans, laborers, servants, and children – come to know the Newtonian universe? And what effects did this knowledge have on how they contextualized their place in society? When it appeared in 1733, Henry Bridges’ “Modern Microcosm” promised to give paying customers a view of the entire universe ingeniously recreated in a ten-foot-tall automaton theater. A hit with audiences, this clockwork wonder was displayed in Britain and the American colonies until disappearing mysteriously in the 1770s. This paper attempts to recover non-elite understandings of public science by examining the career of an astronomical wonder in the rowdy marketplace of ideas that was the London show scene.     

高职高专“机械制造技术”课程教学改革探讨

目前高职高专＂机械制造技术＂教学中存在的问题如：课程内容多授课课时少、教材体系欠合理、实践性教学环节的比重偏少、课程设计要求与生产实际差距大等问题。为了提高教学质量,实现＂机械制造技术＂课程的培养目标,认为有必要优化教学内容,设计课程的教学模块、教学课题、教学任务三级教学体系;改革教学方法,采用项目化教学法;改进课程教学效果的评价方法,采用实践操作、现场答辩、撰写实习报告等多种考核方式。     

H∞ output-feedback control for discrete-time switched linear systems via asynchronous switching

In this paper, we consider the H_∞ hybrid dynamical output-feedback control problem for discrete-time switched linear systems under asynchronous switching. A time-varying multiple Lyapunov-like-function (MLF) approach is applied to derive sufficient conditions that guarantee the stability and weighted l₂-gain performance of the closed-loop systems, where the established conditions explicitly depend on the upper and lower bounds of asynchronous switching delays. An alternative approach is proposed to decouple the bilinear problems of the control synthesis conditions. Convex optimization algorithms are also proposed based on the established conditions to determine the minimum l₂-gain performance. Two numerical examples are provided to illustrate the effectiveness of the proposed method, demonstrating significant improvement over the existing results.     

Consensus analysis for multi-agent systems via periodic event-triggered algorithms with quantized information

In this article, a novel distributed event-triggered control protocol for the consensus of second-order multi-agent systems with undirected topology is studied. Based on the proposed control protocol, the event-triggered condition is evaluated only at every sampling instant. The control input for each agent will be updated with local information if and only if its condition is violated. Both ideal and quantized relative state measurements are considered under this framework. Some sufficient conditions for achieving consensus are derived using spectral properties of edge Laplacian matrix and the discrete-time Lyapunov function method. Finally, numerical examples are given to demonstrate the effectiveness of our theoretical results.     

计算机辅助模具设计中装配图绘制规范

联系当前计算机辅助模具设计制造的实际,分析了一般装配图的特点,归纳了适合当前职业教育的型腔模具装配图的绘制要求。     

对低重心标枪的力学分析

本文以中外优秀男子标枪运动员为对象,从力学角度分析了低重心标枪和旧标枪的特性,通过对新旧标枪的投掷技术的对比研究,得出新旧、标枪在气动性能方面存在明显差异。本文还探索了我国男子标枪运动成绩落后的原因,提出了尽快掌握低重心标枪投掷技术的有效方法。     

乒乓球与球桌碰撞的力学模型

本文建立了一个乓乒球与球桌碰撞的力学模型，并就该力学模型应用冲量定律、冲量矩定理及有关的力学原理进行了较深入的分析讨论。     

基于工作过程的“化工机械设备技术”课程改革与实践

化工机械设备技术是一门理论与实践结合紧密,综合性和实践性很强的专业课程,按照基于工作过程的项目化教学方式组织实施教学,有利于实现教学目标。文章从课程体系、教学内容、教学手段、考核方法等方面对该课程的改革进行了探索,并提出了解决办法。     

“机械设计”课程设计教学改革研究与实践

课程设计是机械设计课程教学的重要组成部分。提高课程设计的教学质量,对培养学生分析和解决工程设计问题的能力起着十分重要的作用。在实际当中“机械设计”课程设计存在诸多不足之处,从而导致教学效果不佳,无法达到预期的人才培养目标。随着教育改革的深入和持续发展,对机械设计课程进行教学改革与重新设计成为了必然的结果。就如何提高机械设计课程设计的教学质量,从设计课题、实物操作、实施模式和绩效评价等方面指出了教学改革的建议和举措。     

基于“微课”背景下高职院校《机械制图》教学模式改革探析

《机械制图》作为高职院校工科学生必修的一门专业技术基础课,被公认为是一门既抽象又难学的专业技术基础课程。在国家大力推进教育信息化的大背景下,通过探讨如何将"微课"应用在高职院校《机械制图》教学模式改革中,让学生从枯燥、抽象的学习方式中解放出来,由无趣学习变为有趣学习、被动学习变为主动学习,从而提高他们对《机械制图》的学习兴趣与效率。