PLC在起重机变频调速控制中的应用

本文介绍了PLC在起重机变频调速控制中的应用,给出了用S7-200自由口控制数台变频器的通信及进行变频器参数设置的方法,并通过STEP7编程进行了具体实现。     

科研体制中的权力维度

本文通过分析发展科研能力的必要性,提出高校和基金会制中,按一定规则赋予科研人员或科研组织一定的行政权力是促进科学发展的重要因素,     

CO_2、NH_3对YBa_2Cu_3O_(7-x)的结构及超导电性的影响

以热重分析(TGA)、电阻测量和X射线衍射分析等方法,研究了CO_2与NH_3对YBa_2Cu_3O_(7-x)超导体结构稳定性及超导,电性的影响。当温度低于373K时,CO_2对YBa_2Cu_3O(7-x)的结构和超导电性无影响;当温度为523K时,CO_2使YBa_2Cu_3O_(7-x)的Tc下降;温度高于703K时,CO_2将很快破坏YBa_2Cu_3O_(7-x)的结构,并产生化学反应,生成新的化合物,在CO_2中存在的O_2与N_2对YBa_2Cu_3O(7-x)与CO_2的反应及反应产物的影响有较大差异。NH_3对YBa_2Cu_3O(7-x)结构稳定性的影响不大。     

Two direct Tustin discretization methods for fractional-order differentiator/integrator

This paper deals with fractional calculus and its approximate discretization. Two direct discretization methods useful in control and digital filtering are presented for discretizing the fractional-order differentiator or integrator. Detailed mathematical formulae and tables are given. An illustrative example is presented to show the practically usefulness of the two proposed discretization schemes. Comparative remarks between the two methods are also given.     

国际大型体育赛事与中国国家形象的时代特征及发展机遇*

我国从近代开始参与国际大型体育赛事,到目前为止已经成为参与、举办国际大型体育赛事较多的国家。在不同的历史阶段,国际大型体育赛事提升国家形象表现出不同的时代特征。当前,一带一路国家战略的积极实施、中国特色大国外交战略的积极推广以及体育强国建设的全面推进,为国际大型体育赛事提升国家形象带来了崭新的发展机遇。     

Drivers of illicit drug use regulation in Australian sport

Most Australian sport stakeholders not only believe that government regulation is a good thing, but also assume that intervention in the drug-use problem will improve sport's social outcomes and operational integrity. In this paper we examine the regulation of illicit drug use in Australian sport through an interrogation of two cases: the Australian Football League and the National Rugby League. Using Pierre Bourdieu's conceptual frames of social field, capital, and habitus, we aim to secure a clearer understanding of the drivers of Australian sport's illicit drug regulations by (1) identifying those stakeholders who set the drug regulation agenda, (2) revealing the values and dispositions that underpin these regulations, and (3) explaining how dominant stakeholders go about sustaining their position and marginalising those stakeholders with opposing drug regulation claims. Our results show that Australian sport's drug-use regulations are driven by a set of values and dispositions that views sport as an instrument for shaping the character of its participants, and drugs as a threat to sport's moral fabric and good standing. The dominant stakeholders, comprising the Commonwealth Government, its sport agencies, and the major governing bodies for sport, imposed these values and dispositions on peripheral stakeholders by designing a drugs-in-sport social field that yielded capital and power to only those participants who endorsed these values and dispositions. Peripheral stakeholders – including players, their agents, and drug-treatment professionals – who mostly shared different values and dispositions, were sidelined, and denied the opportunity of adding to their already limited supplies of capital, power, and policy making influence.     

文化、观念与制度——国家体育软实力理论模型构建与动力机制分析

以文献资料和理论分析为基本方法,在国家体育综合实力的层面提出并深入分析了体育软实力概念。明确了体育观念、体育文化和体育制度等无形的非物质要素是体育软实力的资源基础和载体。以此为基础,构建了包括表层、中层和核心层三个层面的国家体育软实力三维结构模型,并重点对该模型中耦合软实力所包含的文化——观念动力系统、文化——制度动力系统、观念——制度动力系统的动力机制进行了分析,提出了体育软实力建设的对策建议。     

基于PLC和组态王的高效自动化集装箱码头监控系统设计

针对高效自动化集装箱码头物理仿真模型的控制点多、监控界面设计复杂等缺陷,由西门子公司的S7300可编程逻辑控制器和组态王6.53软件设计一套改进的控制系统.系统的硬件部分包括实物模型部分和系统控制部分（S7300 PLC）,系统控制部分由上位机监控系统和下位机控制系统构成.整个网络采用两层网络拓扑结构,上层为通信监控,底层为PROFIBUSDP现场总线.软件部分包括用于为下位机组态、编程以及调试的STEP7和用于监控界面设计的组态王6.53.实验测试表明,该仿真模型监控系统运行良好、稳定可靠.     

飞行试验应变参数自动校准系统的设计

针对目前机上应变参数校准采用手动单通道效率较低,易出现人为误差的现状,应变参数自动校准系统在C＋＋Builder平台上开发,采用Pickering公司的6通道40-265可编程应变模拟卡,通过以太网将KAM500采集器的数据传输,最终实现应变量的自动加载、校线自动生成、存储等。     

基于Cypress单片机的USB键盘设计

USB接口是一种简单易行又能够最大限度地节省计算机软硬件资源的接口,具有真正的即插即用、数据传输速度快、性能稳定等优点,USB设备在近几年得到了迅速普及。本文设计了一种基于Cypress单片机的USB键盘,首先简要介绍了USB接口协议的发展和CY7C63513芯片的特点,然后分析了键盘的硬件电路各部分的原理作用和键盘扫描程序流程。