降温水循环泵恒压供水变频改造

本文介绍了降温水循环泵恒压供水变频改造的特点及变频控制系统与DCS控制应用于降温水循环泵变频调速控制的基本情况。     

变压变频供水系统的节能控制方法

节能供水是一个老问题，但又是一个重要的难题。继《一种节能的变压变频供水系统》一文提出的无线网构成变压变频节能供水系统后，本文以系统思考的理念从改变系统控制软件角度使供水系统结构具有变压变频的节能属性。     

论给水变频控制系统在100MW机组中的应用

引用某热电厂100MW机组给水系统的变频改造实际运行和测试结果，证明在电厂给水系统中应用给水变频控制系统进行改造是切实可行的。不仅可以有效改善系统自动化水平和控制品质，而且可以取得良好的经济效益。     

芯片测试时如何减少电源电压波动之手法

随着半导体芯片的电源低电压化及测试高速化的发展，电源电流的变化也越来越大，由此在芯片测试时对电源电压波动抑制的要求也越来越高。为了在各种测试条件下都能给被测芯片提供更稳定的电源电压，我们开发了一种模块化的解决方法。该模块仅需简单连接在芯片测试用load board上，即能实现为芯片提供高速电流，并将电压波动抑制在50mV范围之内。接下来将结合模块实际使用情况来对该模块改善芯片正常动作环境范围进行介绍。     

基于简化拓扑结构的陕京天然气管网供气可靠性分析

为了定量分析结合了拓扑结构与水力计算的天然气管网的供气可靠性,以陕京天然气管网为分析对象,提出了一种通用的天然气长输管网系统供气可靠性评估方法。首先从上述天然气管网的拓扑结构入手,将站场与天然气管段视为网络结构的结点与链路单元,对系统进行了简化,建立了天然气管网系统的拓扑结构模型;然后通过设备失效数据库确定了系统各单元的事故率分布,耦合基于故障率分布的蒙特卡洛模拟生成了天然气管网的拓扑结构;最后再结合水力计算得到一定拓扑结构下陕京天然气管网的供气能力。结果表明:①无论是用气高月还是用气低月,该管网都保持了很高的供气可靠性;②陕京一、二、三线3条天然气管道构成了具有一定拓扑结构的供气网络,增加了系统的鲁棒性,从拓扑结构层面也提高了供气的可靠性。结论认为,该项研究成果给出了天然气管网供气可靠性的定量计算方法,为天然气管网供气可靠性分析提供了技术支持。     

Food safety pre-warning system based on data mining for a sustainable food supply chain

In recent years, the food safety incidents happened frequently in china, and then the problems related to food quality and safety have attracted more and more social attention. Considering the concern with regard to quality sustainability in food supply chain, many companies have developed a real time data monitoring system to ensure products quality in the supply chain network. In this paper, we proposed a food safety pre-warning system, adopting association rule mining and Internet of Things technology, to timely monitor all the detection data of the whole supply chain and automatically pre-warn. The aim of pre-warning system is to help managers in food manufacturing firm to find food safety risk in advance, and to give some decision support information to maintain the quality and safety of food products. A case study of a dairy producer was conducted, and the results showed that the proposed pre-warning system can effectively identify safety risks and accurately determine whether a warning should be issued, depending on the expert analysis when an abnormality is detected by the system. In addition, implications of the proposed approach were discussed, and suggestions for future work were outlined.     

Detection of unapproved genetically modified potatoes in Korea using multiplex polymerase chain reaction

Several genetically modified (GM) potato cultivars with improved traits such as increased amylopectin levels, decreased asparagine levels, and reduced incidence of black spot have been developed. In this study, we describe a multiplex polymerase chain reaction (PCR) method specific for four GM potato events (EH92-527-1, AM04-1020, PH05-026-0048, and E12) that are unauthorized in Korea. The UDP-glucose pyrophosphorylase (UGPase) gene was used as the endogenous reference gene. The specificity of the primer sets was evaluated using GM potatoes and other GM crops. The limit of detection in the developed multiplex PCR was confirmed to be approximately 0.04% (w/w). Thirty-three commercial products containing potato ingredients were tested by the multiplex PCR assay, and GM potato event E12 was found in one of the 33 samples. This result suggested that the developed PCR method could be used to effectively identify unauthorized GM potatoes in Korea.     

Simulation model for sizing of stand-alone solar PV system with interconnected array

Solar PV arrays made of interconnected modules are comparatively less susceptible to shadow problem and power degradation resulting from the aging of solar cells. This paper presents a simulation model for the sizing of stand-alone solar PV systems with interconnected arrays. It considers the electricity generation in the array and its storage in the battery bank serving the fluctuating load demand. The loss of power supply probability (LPSP) is used to connote the risk of not satisfying the load demand. The non-tracking (e.g., fixed and tilted) and single-axis tracking aperture arrays having cross-connected modules of single crystalline silicon solar cells in a (6×6) modular configuration are considered. The simulation results are illustrated with the help of a numerical example wherein the load demand is assumed to follow uniform probabilistic distribution. For a given load, the numbers of solar PV modules and batteries corresponding to zero values of LPSP on diurnal basis during the year round cycle of operation are presented. The results corresponding to the surplus and deficit of energy as a function of LPSP are also presented and discussed to assess the engineering design trade offs in the system components.Furthermore, a simple cost analysis has also been carried out, which indicates that for Delhi the stand-alone solar PV systems with fixed and tilted aperture arrays are better option than those with single-axis tracking aperture (with north–south oriented tracking axis) arrays.     

基于PLC的变频恒压变流量供水节能系统的研究与应用

针对传统供水系统能源浪费严重、自动化程度低等特点,设计开发了一种以PLC、变频器为核心构成的变频恒压变流量供水系统。介绍了该系统的节能原理、系统构成及工作原理、硬件、软件设计及系统优点,证明了变频恒压控制系统优越的技术性能和极其显著的经济效益,具有很好的推广应用价值和进一步的研究价值。