基于OPCHDA技术的历史数据通讯系统的实现

针对过程控制系统中历史数据通讯接口复杂、数据量大等特点,以OPCHDA技术为基础,构建了一个三层的历史数据通讯系统,并以FPSO历史数据通讯系统为例,详细论述了整个系统的实现过程及其关键技术,为过程控制系统的历史数据通讯提供了一个可行的解决方案.     

成品油管道完整性数据管理

针对管道完整性数据管理存在信息量大、种类繁多、数据分散等难题,从数据模型与数据库建立、历史数据恢复、信息平台建设、数据管理体系构建四个方面针对性地提出相应解决方案。以APDM数据模型为基础,建立成品油管道完整性管理数据模型,涵盖管道中心线及本体,管道运行、周边环境等,设计并建立了基于Oracle数据平台的管道完整性数据库和智能化管线管理系统平台。采用建立数据模型、数据库对示范管道进行了历史数据恢复实践,并依据建立的完整性数据管理体系明确了数据管理流程及职责,提高了管道数据管理效率,满足了完整性数据管理的要求。     

基于联合互信息的动态软测量方法

针对工业过程中普遍存在的时延特性和动态特性,提出一种基于联合互信息的动态软测量方法.以联合互信息最大化作为准则,从各辅助变量的历史输入数据矩阵中选取一个连续子变量集,组成包含过程时延信息和动态信息的新数据集,进而确定各辅助变量的时延参数、历史数据长度.各辅助变量参数完全基于过程历史数据确定,与后续软测量模型的建立无关,因此建立动态软测量模型的形式可根据对象非线性程度自主选择.针对实际脱丁烷塔塔底丁烷浓度软测量的仿真研究验证了方法的有效性.     

构建化工企业的Intranet

本文论述基于ASP和SQL Sever 2000数据库等技术的化工企业的Intranet构建方案,是一种技术简单、安全可靠、普及率高的方案,具有一定的实用价值。     

间歇造气炉上位机监控软件设计

针对煤化工间歇造气炉生产工艺流程,开发一套上位机监控软件.该软件通过自定义的通信协议与造气炉下位机之间进行实时通信,利用主界面模拟现场运行环境,动态显示造气炉各类运行参数;同时,通过建立外部SQL数据库,实现实时数据与历史数据的长久保存;另外,该软件设计有内嵌OPC服务器接口,成功地解决了本系统与其它设备系统之间的通信难题.将其应用于内蒙古乌拉山化肥有限公司的造气生产过程控制中,取得了良好的运行效果.     

蒸汽管网在线监测系统的设计与应用

蒸汽管网在线监测系统是一个B/S(Browse/Server)模式,并以在线模拟与检测技术和ORACLE数据库技术为基础的蒸汽管网监测系统,本系统的主要功能:管网基本信息管理、实时工况监测以及历史数据查询.本系统的应用有效地帮助企业提高了蒸汽管网管理水平,增强蒸汽系统运行的安全性和可靠性,收到明显的节能降耗效益.     

基于PLC和组态技术的智能干油润滑系统设计

介绍了西门子S7-200PLC和WinCC组态软件在润滑控制系统中的应用,通过分析干油润滑系统的特点,提出了一种智能干油润滑系统的总体设计方案.在设计的计算机监控系统中集成了总线技术和组态技术,利用工控机和PLC组成上、下两级分布式监控系统.上位机采用工控软件WinCC实现工艺流程、报警、历史曲线的显示报表以及数据库查...     

抓住新形式下的发展机遇促进生物化工产业集群化发展

在当前金融危机形势下,生物化工产业面临新的挑战与难得的发展机遇.阐述了生物化工产业作为当今世界经济发展的一个新的增长点.通过分析指出集群化发展是当今世界高技术产业发展的重要趋势和一般规律,也是发展我国生物化工产业的重要途径.新形式下一定要抓住实现跨越发展的历史契机,促进我国生物化工产业集群化发展.     

学校应用系统数据库设计研究

学校数据库系统是学校业务应用的核心组件,它的设计至关重要。为了保障数据库系统经济、高效、可靠的运行,要尽量减少数据库类型和数据库实例。在目前大多数数据中心采用了虚拟化技术之后,以Oracle为例,从数据库性能和数据库集群部署方式两方面阐述应如何设计。     

基于OPC的聚合物动态塑化挤出实时监控系统设计

针对目前聚合物动态塑化挤出过程控制中，监控系统对于多变量实时数据的批处理和对历史数据的访问与分析的效率不高，难于实现精密化控制的问题，提出了一种基于OPC技术的实时监控系统设计方案。该方案已成功运用于“聚合物动态流变综合测试仪”中，其性能稳定，数据传输速率很快，达到了工业现场高效率的实时数据传输要求，大大降低了数据传输过程中的差错率，从而实现各变量的实时精密控制。     

改进型无线传感器网络安全分簇路由协议

无线传感器网络路由协议对无线传感器网络起着非常重要的作用,是无线传感器网络的关键技术之一。本文基于经典的LEACH算法提出一种改进型LEACH-R,主要体现在对簇首的考虑上。簇形成阶段引入对加入簇节点的身份验证机制以及对候选簇首广播消息的认证。簇稳定阶段引入簇内节点对簇首广播消息进行认证的机制。计算机仿真对比实验结果表明,LEACH-R协议能够延长网络寿命,使用网络的安全性得到提高,网络性能得到改善。     

Classification of monofloral honeys by voltammetric electronic tongue with chemometrics method

A voltammetric electronic tongue (VE-tongue) based on multifrequency large amplitude pulse voltammetry (MLAPV) was developed to classify monofloral honeys of seven kinds of floral origins. The VE-tongue was composed of six working electrodes (gold, silver, platinum, palladium, tungsten, and titanium) in a standard three-electrode configuration. The applied waveform of MLAPV was composed of four individual frequencies: 1 Hz, 10 Hz, 100 Hz, and 1000 Hz. Two eigenvalues (the maximum value and the minimum value) of each cycle were extracted for building the first database (FDB); four eigenvalues (the maximum value, the minimum value, and two inflexion values) were exacted for building the second database (SDB). The two databases were analyzed by three-pattern recognition techniques: principal component analysis (PCA), discriminant function analysis (DFA) and cluster analysis (CA), respectively. It was possible to discriminate the seven kinds of honeys of different floral origins completely based on FDB and SDB by PCA, DFA and CA, and FDB was certificated as an efficient database by contrasting with the SDB. Moreover, the effective working electrodes and frequencies were picked out as the best experimental project for the further study.     

Influence of low molecular weight ABS species on properties of PC/ABS systems

Differential scanning calorimetry (DSC), scanning electron microscopy (SEM) rheological, mechanical and impact tests were performed on alloys consisting of polycarbonate (PC) and diverse acrylonitrile‐butadiene‐styrene copolymers (ABS), from which different amounts of low molecular (M) weight (W) species had been previously extracted in a Soxhlet apparatus by methanol. The influence on properties of the alloy composition and of the low MW species amount was investigated. The glass transition temperature (Tg) was found to be a useful probe for monitoring the migration trends of low MW ABS species towards the PC domains for the different alloys. In a morphological analysis it was found that the higher the ABS extraction extent the less the penetration of the etching agent into the surfaces of smoothed specimens. The blend rheological behavior showed that the capability of improving the PC processability, characteristic of commercial ABS's, was strongly lowered by the ABS extracted ones. The alloy modulus was higher when the ABS extraction extent was larger. The yield stress of alloys showed higher values than that of the PC one, particularly at low ABS content. The alloy composition, for which the impact resilience was at its maximum value, strongly depended on the extraction extent. All the above findings seem to suggest an increased adhesion between PC and ABS domains with enhanced extraction amounts of low MW species from the ABS component.     

化工设计企业的信息化解决方案

根据建设部制定的工程设计企业信息化规划的要求，结合化工设计企业的特点，从网络规划，系统安全，计算机集成应用系统的项目管理，设计流程管理，电子文档管理，协同设计先进子系统的功能和实现方法，工程数据库的建立以及相关的管理措施等方面论述了化工设计企业实现信息化的具体方案。     

我国聚碳酸酯合成技术发展前景

重点介绍了PC合成技术的发展历程和发展方向,对主要PC合成技术特点进行了比较,提出了我国PC合成技术开发存在问题,并预测了将来的发展前景.     

新型增容剂在PC/ABS合金中的应用

介绍了三种不同类型的新型增容剂并与传统的增容剂（PE-g-MAH)对比了在PC／ABS合金体系中的改性效果，试验表明，这三种增容剂对PC／ABS合金的增韧比PE－g-MAH效果都要好，其中，增容剂E3比E1，E2具有更好的增韧效果，同时还有增强作用，而且E3在PC／线性饱和聚酯合金体系中也有非常好的增韧效果，这种新型增容剂用量少，成本可接受，为PC合金的性能提高提供了一个较好的选择。     

基于多代理的异构数据库转换系统的实现

用多代理技术给出了一种数据库转换与同步策略,引入新的访问控制机制。在保证各个参与数据库自治,维护其完整性、安全性的基础上,实现异构数据库的转换。用多代理工具jade实现了该系统模型,为化工企业在数据库系统升级过程中给出了一个可行的异构数据库转换系统的解决方案。     

Reinforcing the phenomenological consistency in artificial neural network modeling of multiphase reactors

Artificial neural networks (ANN) aided with dimensional analysis have been successfully applied in multiphase reactors modeling when considerable amount of experimental data (or database) is available. An important problem that stemmed from this approach was the ambiguity to select the fittest combination of dimensionless numbers to be used as ANN inputs to predict a variable of interest. A genetic algorithm (GA) based methodology was proposed to optimize the combination of inputs by taking into account the phenomenological consistency (PC) of the resulting ANN models along with their fitting capabilities. PC is a measure of the capability of an ANN model to simulate outputs with specified gradient conditions with respect to the process variables. These conditions are imposed based on a priori knowledge of the system's behavior. PC used to be evaluated in the vicinity of a particular point in the database space. The novelty of the approach was the extension of the PC test around all the points available in the training data set. This technique may be regarded as a robust method to prevent data overfitting when the function to be learned by ANN is characterized by a monotonic behavior with respect to some of the process variables. The new approach was illustrated using as a case study the correlation of two-phase pressure drop in randomly packed beds with countercurrent flow.     

浅析重金属污染防治规划保障措施

重金属污染防治工作是一项涉及各区、各部门的复杂的系统工程,为更好地开展重金属污染防治工作,从机制、政策、资金和技术4个方面提出保障措施。通过分析可知,政策保障是前提,机制保障是有力手段,资金保障和技术保障是基础,只有四者有机结合,发挥各自作用,才能保证重金属污染防治规划目标和任务的实现。     

Rural development, household food safety, and nutrition in western Honduras

The authors studied the impact of a rural development project on household food security and nutrition. A quasi-experimental study design was used to compare the experience of members of thirteen Honduran small-holder farmers groups which had already received a year of credit and technical assistance, with another thirteen groups which had just joined the project, and thirteen control communities. All these communities were followed-up for one year (March/April 1997-March/April 1998). Farmers participating in the project showed a greater increase in maize stores than farmers in the control communities (p = 0.01), but did not increase their dietary energy consumption. There was, however, a small improvement in their dietary diversity (p = 0.01). The impact of the project on the nutritional status of under 5's was complex. The study underlined the importance of monitoring the impact of programs which may affect food and nutrition.