基于以太网的现场网络化控制系统

为使分布在不同地域的现场控制设备和控制系统有机地连接成一体,达到宽广地域的远程监视与控制,提出了基于以太网的现场网络化控制系统.该系统设计采用以太网作为现场设备之间的通信网络,在研究基于以太网的现场网络化控制系统结构的基础上,开发了现场网络化控制系统可视控制组态平台和现场网络化控制系统可视监控组态平台.该系统具有成本低、结构简单、可靠性高、控制分散,可实现真正的"E网到底"控制等特点,能够组成开放式自动化控制系统;因而可克服以往集散控制系统和现场总线控制系统的局限性,大大降低控制系统的成本、提高控制系统的性能,并获得优良的性能价格比.该系统的研究与开发,可应用于缩短工业控制系统的开发周期.     

基于工业以太网和现场总线互连的氧化锌生产线网络控制系统

为使分布在不同地域的现场控制设备和控制系统有机地连接成一体,达到宽广地域的远程监视与控制,提出了基于以太网和现场总线互连的氧化锌生产线网络控制系统.该系统设计采用以太网作为企业网的上层设备之间的通信网络,将主控制器、操作员站及管理计算机连接起来.在企业网的最底层采用现场总线的形式.该系统具有成本低、结构简单、可靠性高、控制分散,可实现真正的“全分布式”控制等特点,能够组成开放式自动化控制系统;因而可克服以往集散控制系统和现场总线控制系统的局限性,大大降低控制系统的成本、提高控制系统的性能,并获得优良的性能价格比.     

工业以太网在现场总线控制系统中的应用

分析工业以太网现场总线控制系统中的应用,通过工业以太网把所有的现场设备、控制器件和计算机工作站集成为一个高度可靠、低功耗和实时的控制系统;并通过 micro_I/A 现场级控制子系统,进行逻辑控制、批量控制和连续控制。实践表明工业以太网的介入使现场总线能更好的满足实时控制的要求,最大限度使用了数字化通讯和分布式计算技术。     

Delta机器人控制系统研究

随着Delta机器人的迅速发展,其应用范围越来越广,对控制系统性能的要求也越来越高。为满足复杂的工业环境需求,提高控制器的开放性和通用性,设计并测试了一种开放式Delta机器人控制系统。系统硬件方面以微控制器STM32F103ZET6和运动控制芯片MCX514为核心芯片,并基于STM32F103ZET6配备了USB接口和以太网接口,以满足不同的接口需求。软件方面分别使用C语言开发上位机,采用串口和以太网协议作为通信协议。该控制系统成本低、开放性强。试验结果证明,系统精度高,运行稳定,能准确控制机器人进行连续运动。     

烟丝装箱控制系统的改进

为满足烟丝装箱的物流和信息流的同步、高效传送以及远距离数据共享,在烟厂现有装箱设备的基础上对烟丝装箱控制系统进行改进.改进的系统主要采用PLC结合PROFINET网络控制的控制模式,由PROFI-NET、主控PLC、装箱PLC、上位机、RFID识别控制系统等组成.烟丝装箱后的参数信息写入集装箱内的载码卡片上,RFID控制器读取载码卡片上的信息后,可直接通过PROFINET、以太网与PLC、上位机进行数据交换,从而可以有效地实现数据的读取迅速、同步传递,大大地简化了现场设备的互连.     

基于以太网的温度控制系统设计

为了办公自动化网络与工业控制网络的信息无缝集成,进而与Internet连接,实现控制系统的网络化,选择以太网作为控制网络,并搭建了单片机控制以太网网卡芯片进行数据传输实现设备通信的平台,选择电加热炉为被控对象,采用模糊逻辑智能控制方法进行控制。系统仿真结果和现场运行结果表明,模糊控制方法很好地实现了控制目的。该设计成果对推进控制系统网络化具有参考和应用价值。     

基于STM32的TSC型无功补偿控制系统的研究

针对在电力系统网络中,大量电机负荷及大功率设备的投入,出现的功率因数较低、电压波动较大等问题,本文在详细分析无功补偿的相关理论和算法的基础上,研究一种基于STM32的晶闸管投切电容器(TSC)无功补偿控制系统,包括补偿方案、控制算法以及控制器的硬件设计和软件设计等。该系统主控芯片采用STM32芯片,执行模块采用CF6G-3型可控硅触发控制器,信号的采集采用功率测量芯片CS5463,并在控制策略上对常规的九区图做了改进,避免设备的误动作与投切振荡现象的发生,对无功功率进行实时动态补偿。实验结果表明,所设计的无功补偿控制器能够控制电容器准确快捷投切,测量数据精确,补偿效果明显,有效地改善了电网电压供电水平,提高了功率因数,并实现系统在无人值守下的安全高效运行。     

微控制器的嵌入式Internet接入研究

主要介绍利用微控制器MCU为核心的以太网 -CAN网关原理 ,将现场总线CAN总线系统直接连接在以太网上。它既可以将普通CAN接口测控设备变成以太网络测控设备 ,通过互联网进行数据的传送 ;也可以在一些大型分布式测控系统中采用以太网 -CAN接口模块 ,方便地将原来现场总线控制系统升级为以太网络分布式控制系统。     

基于以太网的温度控制系统设计

为了办公自动化网络与工业控制网络的信息无缝集成,进而与Internet连接,实现控制系统的网络化,选择以太网作为控制网络,并搭建了单片机控制以太网网卡芯片进行数据传输实现设备通信的平台,选择电加热炉为被控对象,采用模糊逻辑智能控制方法进行控制.系统仿真结果和现场运行结果表明,模糊控制方法很好地实现了控制目的.该设计成果对推进控制系统网络化具有参考和应用价值.     

浅析远程监控技术

远程监控系统是指利用计算机通过网络实现对生产过程控制系统的监视和控制,突破了地域上的制约而实现异地监视和控制生产过程现场设备。传统的工业控制网络是基于现场总线的,由于现场总线的通讯标准尚未统一,使得现场总线的标准各种各样,这使设备在不同的现场总线监控系统中难以兼容。此外,现场总线目前尚处于低速阶段,难以满足数据高速传输的需要。因此本论文通过和现场总线的对比,分析了在工控领域中,以太网技术的优势。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-