网络环境下楼宇自动化控制的新发展

本文筒要介绍了楼宇自动化系统,分析了传统集散控制系统争新兴的现场总线控制系统优缺点以及应用,并介绍了楼宇自控领域中流行的四种现场总线.说明了以太网技术的发展以及在楼宇自控领域中的最新应用情况,对现场总线控制系统和以太网进行了比较.     

现场总线控制系统FCS必将取代集散型控制系统DCS

文章简要介绍了现场总线控制系统FCS及其发展状况,通过与集散型控制系统DCS的对比,显示出了现场总线控制系统FCS的优越性,指出了FCS将是工业自动化领域控制系统中的一个发展趋势。     

现场总线技术的发展及现状

计算机集散控制系统（DCS）的普遍使用给工业过程控制带来了很大的变化，并逐步完善形成了“第三代”DCS，在此基础上出现了现场总线结构。而一个国际统一的现场总线标准将给仪表制造、过程控制、计算机等众多领域带来根本性的变革。本文叙述了它的特点、构成、功能和优势。在此基础上重点分析了现场总线的现状。     

基于现场总线的集散控制系统——FCS

文章介绍了基于现场总线的集散控制系统的技术特点,硬件及软件体系构成,并对基于现场总线的集散控制系统和传统控制系统的可靠性进行了比较。     

现场总线控制系统在应用中存在问题的分析

现场总线控制系统（FCS）主要由新型智能传感器、现场总线以及相应管理软件组成。同传统的集散控制系统（DCS）相比,现场总线控制系统（FCS）具有更高的可靠性和精度。当前现场总线控制系统在国内的应用中尚存在着包括价格、冗余及维护等方面的问题。但是这一系统正在不断飞速发展中。     

DCS和FCS及其在火电厂中的应用

介绍了集散控制系统和现场总线控制系统，并对它们在火电厂中的应用做了分析。     

浅析FCS控制系统的优缺点及发展

介绍现场总线系统的技术含义、技术特点和技术优势;对现场总线控制系统(FCS)与集散控制系统(DCS)的优缺点进行了分析比较;对现场总线线控制系统的发展现状提出了新的要求。     

现场总线控制系统及其应用

针对一般集散控制系统（DCS）各控制单元间没有通信联系，控制单元之间只能通过上一级的决策单元交换信息和互操作性差等，常导致系统难以达到期望的性能指标，本从总体层面讨论克服了上述不足的现场总线控制系统，包括现场总线的定义、特点、现场总线控制系统的结构及其在自动化系统中的应用。     

基于现场总线技术的火力电厂综合自动控制系统设计研究

现场总线控制技术在工业现场过程控制中已经得到越来越广泛的应用。针对传统的集散控制方式在电厂综合控制系统中的弊端,重点分析了基于现场总线技术的电厂综合自动控制系统的构建,通过对控制系统的网络结构和控制实现方式的探讨,初步实现了火力电厂综合自动控制系统的建设,对于现场总线技术工业过程控制的研究有一定的借鉴意义。     

过程控制技术的发展及展望

本文重点介绍过程控制技术从基地式仪表控制系统伊世始，经历了电动单元组合式模拟控制仪表系统、计算机集中式数字控制系统、集散式控制系统DCS(Distributed Control System)和现场总线控制系统，揭示了其发展的必然过程以及今后发展的必然趋势。     

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.     

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.     

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with