500kV同杆并架双回线路感应电压和感应电流的计算及接地开关的选择

针对500 kV龙滩—沙塘部分同杆并架双回线路的感应电流和感应电压,利用EMTPE程序进行模拟计算分析,为线路接地开关选择提供依据,确保系统运行的可靠性,同时给出接地开关的配置方案和推荐方案。     

基于系统动力学的某市水环境承载力动态变化研究

在对某市社会、经济、环境系统分析的基础上,建立了该市的水环境承载力系统动力学模型,针对目前该市水环境存在的问题提出了9种水环境保护模拟方案。通过对各个方案下水环境承载力的动态变化分析比较,确定出了符合该市社会经济可持续发展要求的最优方案,从而为该市走可持续发展道路提供了科学的决策依据。     

河北平原地下咸水资源利用的效应分析

河北平原在严重缺乏淡水的同时,也蕴藏有大量的地下咸水,如何合理开发利用地下咸水已成为缓解河北平原水资源危机和改善生态环境的关键问题。地下咸水的开发利用有直接利用和间接利用两种模式。大量的实验证明,合理开发利用浅层咸水,使咸水水位降低到合理水平,可以：避免地下水的无效蒸发,增加水资源量;增强调蓄能力和抗旱防涝能力;促进浅层咸水淡化,改造盐碱地,改善生态环境;减轻对淡水资源的威胁。经计算,若将地下咸水水位降低到10m,在避免海水入侵的情况下,河北平原将有54×10^8m^3的咸水可以利用。     

基于DCS的麦芽干燥自动控制系统研究

该文介绍了以PLC为现场控制单元、以上位机为集中管理器的麦芽干燥集散控制系统。描述了该系统的体系结构、组成以及基本控制流程。通过该控制系统实现了麦芽干燥过程的自动有效控制，通过上位机实现了麦芽干燥过程的流程监控。     

HACCP在学生饮用奶生产中的应用

本文研究了HACCP系统在学生饮用奶生产中的应用，进行危害分析（HA），确定关键控制点（CCP），并制定相应控制限值，监控体系的HACCP计划工作模式，以提高学生饮用奶生产管理水平和产品安全性。     

中国学生营养餐现状分析及对未来发展的思考

详细分析了中国学生营养餐的现状,并对学生营养餐未来的发展进行了思考。     

一种新颖的万能式断路器短路短延时动作可返回试验方式

提出了一种万能式断路器短延时动作可返回试验方法。在多磁路变压器一次侧接入一个可调阻抗和一个机电式投切开关（如接触器）,通过程序控制器控制投切开关的闭合与断开时间,实现了二次侧电流从万安级短时间通电后返回至千安级。     

中小型交流电机自动检测保护装置的研制

介绍了一种用于发电机组、电机等设备在线故障检测和保护报警的控制系统．该系统采用以８０９８单片机为核心的控制器件及其外围电路，通过对电压、电流采样并对检测到的参数进行处理，实现了自动检测、故障自诊断、保护报警以及在线设置参数等功能．它可以降低成本，减少组装和调试工作，缩小控制屏体积，减少内部构件，效益明显．     

Effects of genomic selection on genetic improvement, inbreeding, and merit of young versus proven bulls

Genomic selection has the potential to revolutionize dairy cattle breeding because young animals can be accurately selected as parents, leading to a much shorter generation interval and higher rates of genetic gain. The aims of this study were to assess the effects of genomic selection and reduction of the generation interval on the rate of genetic gain and rate of inbreeding. Furthermore, the merit of proven bulls relative to young bulls was studied. This is important for breeding organizations as it determines the relative importance of progeny testing. A closed nucleus breeding scheme was simulated in which 1,000 males and 1,000 females were born annually, 200 bulls were progeny tested, and 20 sires and 200 dams were selected to produce the next generation. In the “proven” (PROV) scenario, only cows with own performance records and progeny-tested bulls were selected as parents. The proportion of the genetic variance that was explained by simulated marker information (M) was varied from 0 to 100%. When M increased from 0 to 100%, the rate of genetic gain increased from 0.238 to 0.309 genetic standard deviations (σ) per year (+30%), whereas the rate of inbreeding reduced from 1.00 to 0.42% per generation. Alternatively, when young cows and bulls were selected as parents (YNG scenario), the rate of genetic gain for M = 0% was 0.292 σ/yr but the corresponding rate of inbreeding increased substantially to 3.15% per generation. A realistic genomic selection scheme (YNG with M = 40%) gave 108% higher rate of genetic gain (0.495 σ/yr) and approximately the same rate of inbreeding per generation as the conventional system without genomic selection (PROV with M = 0%). The rate of inbreeding per year, however, increased from 0.18 to 0.52% because the generation interval in the YNG scheme was much shorter. Progeny-testing fewer bulls reduced the rate of genetic gain and increased the rate of inbreeding for PROV, but had negligible effects for YNG because almost all sires were young bulls. In scenario YNG with M = 40%, the best young bulls were superior to the best proven bulls by 1.27 σ difference in genomic estimated breeding value. This superiority increased even further when fewer bulls were progeny tested. This stochastic simulation study shows that genomic selection in combination with a severe reduction in the generation interval can double the rate of genetic gain at the same rate of inbreeding per generation, but with a higher rate of inbreeding per year. The number of progeny-tested bulls can be greatly reduced, although this will slightly affect the quality of the proven bull team. Therefore, it is important for breeding organizations to predict the future demand for proven bull semen in light of the increasing superiority of young bulls.     

基于Petri网的PLC程序设计方法研究

针对传统程序设计方法难以对具有并发、协调、竞争等复杂事件的PLC控制系统编程的问题，探讨了一种基于Petri网模型的PLC程序设计方法。该方法利用Petri网的图形性质和对并发事件建模的能力，可简便、直观地构建PLC控制系统程序，并能对控制系统性能进行分析，以确认程序的合理性。