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。     

基于现场总线的网络故障分析

现场总线是用于过程控制现场仪表与控制室之间的一个标准的、开放的、双向的多站数字通信系统。本文介绍了变电站综合自动化系统中常用的两种现场总线：CAN（Controller Area Network控制器局域网）、LonWorks（Local Operation Network局部操作网）。。详细分析了基于RS-485现场总线网络的故障查找与排除方法。     

浅析FF基金会现场总线

说明基金会现场总线的特点及标准,详细介绍FF总线所挂接仪表数量和连接电缆长度的算法,阐述FF总线本质安全防爆的方法。通过列举应用实例,说明该总线系统有着广阔的发展前景。     

现场总线技术的发展及应用选择浅析

介绍了现场总线技术的优点、发展过程及多协议标准的形成 ,分析了当今几种典型现场总线的技术特点及优势。面对多协议标准并存的现实及统一标准形成的不可预期性 ,就国内现场总线技术应用开发的技术与经济环境 ,提出了国内现场总线技术应用开发的道路及不同应用领域现场总线协议的择优选型     

现场总线控制系统的应用优势

从分析现场总线系统产生的原因入手,总结其发展历程,阐述了现场总线系统的应用优势;结合实用总线设备和现场总线系统的集成,论述了现场总线控制系统的结构和组成。指出现场总线系统在工业控制中的应用,保证了控制计算和作用的网络化实现,并使得控制系统的系统结构趋于扁平化,为系统组织重构和工作协调的实施提供了可能。     

基于高速以太网的现场总线控制系统

分析各标准的现场总线与高速以太网集成的必要性、可能性及其应用技术.研究现场总线与以太网互联的方法,使不同标准的现场总线与以太网相结合,共同组成全分散、全开放的控制网络.     

网络控制与现场总线

给出了现场总线的基本概念,现场总线的特点,以及现场总线较之DCS的优点;现场总线在国际上对仪表和系统带来的影响;现场总线的基本设备等。     

石油化工现场总线控制技术简述

现场总线控制技术作为工业标准的新的现场解决方案,它与传统的过程控制技术相比较有许多明显的优势。文章从各个方面对现场总线控制技术做了明确的分析和比较,并且给出选用何种总线标准的建议。     

现场总线技术的发展及应用选择浅析

介绍了现场总线技术的优点，发展过程及多协议标准的形成，分析了当今几种典型现场总线的技术特点及优势。面对多协议标准并存的现实及统一标准形成的不可预期性，就国内现场总线技术应用开发的技术与经济环境，提出了国内现场总线技术应用开发的道路及不同应用领域现场总线协议的择优选型。     

现场总线技术在小区污水处理电气控制系统中的应用

在简要介绍现场总线技术及现场总线控制系统结构和优点的基础上,重点分析了PROFIBUS现场总线在水处理系统远程提升泵站监控系统中的通信实现。     

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     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has