搅拌设备控制系统的输入信号预处理电路设计

为了提高沥青混凝土搅拌设备计算机控制系统的可靠性，针对其工作环境对输入信号预处理电路的特殊要求，通过比较的方法，论述了温度检测和配料称量等模拟信号及开关量输入信号处理电路设计的依据，并设计了相应的电路。针对变频器输出频率显示信号中的高频噪声，设计了相应的噪声消除电路，给出了进一步提高系统抗干扰能力的措施。将设计的电路应用于LB2000和LB3000型沥青混凝土搅拌设备计算机控制系统，进行了测试。测试结果表明：输出信号稳定，且消除了高频干扰，提高了系统的可靠性和抗干扰能力。     

基于冲量自修正的间歇式沥青混合料动态配料系统

本文提出了一种高精度间歇式沥青混合料搅拌设备配料系统,配料过程采用冲量自动修正技术保证搅拌设备石料配置的精度,采用沥青二次称量控制技术控制沥青混合料的油石比,解决了传统间歇式沥青混合料搅拌设备存在的配比精度低、响应速度慢及性能不稳定等问题.该系统使用PLC作为主控制器,上位监控软件利用OPC技术与PLC进行通讯以实现数据采集和远程控制.使用情况表明,该系统运行稳定,完全满足沥青混合料配料的精度和速度要求.     

沥青混凝土搅拌设备的使用管理

在沥青路面的施工中使用的沥青混凝土搅拌设备一般均为强制间歇式设备，其主要由控制系统、冷料供给系统、烘干加热系统、热料粉料供给系统、搅拌器、成品料储存仓（包括成品料小车）、除尘系统及沥青加热储存供给系统等构成。对于设备的一般使用保养，各设备的随机资料均已作出详细说明，因此本文仅就我们在历年的工作中遇到的问题及解决方法进行一些探讨。     

浅析我国沥青搅拌设备的现状和发展趋势

本文从沥青混凝土搅拌设备的结构入手，阐述了间歇式和连续式混凝土搅拌设备的差异，分析了目前我国沥青搅拌设备行业的发展现状，以及设计和制造中仍需解决的问题，并且结合未来公路行业的发展动态，对我国沥青搅拌设备制造行业未来的发展趋势进行了展望。     

沥青混凝土拌和设备控制系统的设计与开发

提出了基于SIMENES S7-300 PLC的沥青混凝土拌和设备控制系统的总体框架，叙述了计算机控制系统软件中关键技术的实现方法，系统程序使用VC 6．0开发实现，程序中采用了多线程串口通讯技术及ADO数据库编程技术，经使用满足生产需要。     

沥青拌和机除尘技术创新设计研究

沥青拌和机是沥青路面施工中较为重要的设备,主要用于公路沥青路面大、中修的沥青混合料的生成。传统的沥青拌和机构造简单、投资少、动力消耗低,其除尘效果也比较低。而沥青混凝土搅拌设备在烘干、筛分、热骨料的输送和搅拌等工序中产生大量烟尘,主要是石料系统产生粉尘,使用时对周边环境产生很大污染。对沥青拌和机进行除尘技术改造,势在必行。     

浅谈LBY600型沥青混凝土拌和设备沥青计量筒结构改进

针对LBY600型沥青混凝土拌和设备使用期间,其单筒式沥青计量筒存在计量不稳定,沥青流量不好控制,造成沥青混凝土质量得不到有效保障,为解决该问题,笔者与厂家将单筒式沥青计量筒改进为双筒式保温计量筒,使沥青流量得到很好保障,解决了沥青混凝土的质量。     

基于模糊PID控制沥青砂浆车液压调平系统

针对施工中沥青砂浆搅拌车的计量设备受其水平度影响大和频繁移动的特点,以可编程逻辑控制器(PLC)为控制核心,开发了4点液压调平系统,分别以PID(比例、积分、微分)和模糊PID为调平控制方法进行试验对比研究。结果表明:在满足调平精度为±0.1°前提下,模糊PID调平控制的调平时间为8.5 s,PID调平控制的调平时间为23 s;模糊PID控制通过优化调平过程中阀的开度,能够显著提高调平效率和调平精度,基于模糊PID控制调平能提高沥青砂浆车的计量精度和施工效率。     

我国沥青混合料搅拌设备发展状况

沥青混合料搅拌设备是修筑沥青路面的关键大型专用路面机械设备。其功能是依据沥青路面施工技术规范要求,将基配骨料、沥青、矿粉以及各种添加剂按设计配比和精度加热搅拌成为多种规格的热拌沥青混合料,用于铺筑沥青路面。     

基于PLC和工控机的间歇强制式沥青混凝土搅拌站控制系统设计

沥青混凝土搅拌站属于大型的成套设备,对电气控制系统的要求比较高。就此研究了间歇强制式沥青搅拌站,在分析间歇强制式沥青搅拌站的生产工艺要求的基础上,设计其控制系统,包括PLC控制系统和监控系统,同时,给出了控制程序流程图。实践表明,这种控制系统对间歇强制式沥青混凝土搅拌站的控制是合理可靠的。     

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.     

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     

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

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