PLC与变频器在四层电梯教学模型中的应用

PLC与变频器在电梯控制系统中的应用非常广泛。本文介绍了四层教学电梯模型中PLC与变频器控制的设计思想,提出了适用于高层电梯控制程序设计的编程方法。     

基于PLC脉宽调制控制的变频调速系统应用设计

以六层电梯模型中的变频调速部分为例，论述了脉宽调制(PWM)的应用设计。此设计增强了电梯舒适感和平层定位精度，对中小型电梯企业具有应用推广价值。     

三层电梯PLC控制系统的设计

本文阐述了可编程控制器在三层电梯控制系统中的应用,主要从电梯的控制要求、PLC选择、I/O分配、梯形图的设计与调试等方面进行了软件和硬件上的设计,并实现了一种三层电梯的控制系统的设计。     

电梯案例教学在《机电一体化系统设计》课程中的应用

对《机电一体化系统设计》课程特点进行了分析,将电梯案例应用在该课程中。阐述了电梯案例的教学内容设置,实施步骤、案例实施中的注意事项及教学实践效果分析。通过实践表明电梯案例教学法在《机电一体化系统设计》课程中的应用是成功的。     

基于MC35i的GPRS无线通信在电梯检验中的应用

随着电梯的不断普及,电梯运行安全的检验任务量不断增大,为提高电梯检验的效率,设计一种电梯实时运行时的检验设备,并将基于MC35i的GPRS技术应用到设备通信中,完成实时数据传输功能。首先介绍了电梯检验设备的系统结构,然后详细介绍了MC35i电路设计,S3C2440处理器及其时钟和存储电路,最后给出MC35i模块以及设备系统的程序设计和软件流程图。实际应用中,检验员使用该设备进行电梯检验,利用自动检验和实时上传数据功能,能够快速、准确的完成电梯检验任务,极大提高工作效率。     

电梯模拟系统的研究与设计

电梯模拟系统是对实际生活中电梯调度运行情况的模拟.在研究与设计该系统的过程中,设计了电梯调度算法来控制电梯的调度过程,使用双缓冲技术来解决电梯图片在刷新过程中出现的闪烁现象;使用Java语言作为开发工具,通过创建类及类的属性和方法来实现系统模块的功能.该系统实现了对电梯运行过程中状态和行为的模拟,促进了虚拟现实技术的应用与发展.     

基于ARM的电梯远程监控系统服务器端设计

应用网络通信技术,开发了基于ARM的电梯运行状态的远程监控系统服务器端,为电梯在运行过程中故障的发现、分析和排除提供了设计依据。     

基于单片机的电梯控制模型实验教学系统的设计

电梯控制模型是一种实验教学演示系统。本文阐述了电梯控制模型在实验教学中的应用，介绍了基于单片机的电梯控制模型的主要特色。给出了系统的硬件设计和软件设计。     

基于S7-200和触摸屏的电梯控制实验项目的分层设计

利用电气控制实验室的SIEMENS S7-200和触摸屏,结合电梯控制教学模型,设计了电梯控制实验项目。介绍了电梯控制电路的硬件结构,软件设计要求和人机界面的组态。将电梯控制实验应用于开放实验教学中时,面向不同的学生和不同的培养目标,设计了基础应用型、创新研究型和毕业设计型三个应用层次。面向不同的应用层次,在实验的设计上具有不同的侧重点和不同的实验要求,实现了多元化的分层培养模式。将现代工业控制对象应用于实验教学,不但提高了学生的动手能力和实践能力,更有利于培养学生的综合素质和创新思想。     

基于DSP永磁同步电机的电梯应用研究

以DSP系统和永磁同步电机在电梯中的应用为目标,讨论了电梯控制系统的结构、矢量控制的基本原理、基于DSP的永磁同步伺服系统的软硬件组成及设计方案,采用TMS320LF2812数字信号处理器,实现了对电梯永磁同步电机的矢量控制。实验结果表明：应用高速DSP芯片,采用矢量控制的永磁同步电机电梯拖动系统具有良好的动态响应性能和静态性能,并具有结构紧凑,设计合理,控制灵活等优点。     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

Social and Cultural Influence on Word Meaning

Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.