Study on Modeling for Pretreatment and Cyclic Control Stream

The characteristics of pretreatment and cyclic control stream are analysed:the form of cyclic embedded hardware circuit,the idea for designing the pretreatment program.The chart model of the system is established preliminarily.     

葡萄霜霉病研究进展

文章介绍了葡萄霜霉病病害症状及侵染循环过程,归纳了其对卵孢子的形成发育及该病菌侵染后相关分泌蛋白的产生与变化,总结了葡萄霜霉病的致病机理。同时针对目前葡萄霜霉病的防治手段,分别从选育抗性品种、农业物理防治、生物防治、化学防治及综合防治等方面进行梳理与综述,以期为后续的葡萄霜霉病的研究与病害治理提供参考。     

The environmental performance of milk production on a typical Portuguese dairy farm

The activities associated with raw milk production on dairy farms require an effective evaluation of their environmental impact. The present study evaluates the global environmental impacts associated with milk production on dairy farms in Portugal and identifies the processes that have the greatest environmental impact by using life cycle assessment (LCA) methodology. The main factors involved in milk production were included, namely: the dairy farm, maize silage, ryegrass silage, straw, concentrates, diesel and electricity. The results suggest that the major source of air and water emissions in the life cycle of milk is the production of concentrates. The activities carried out on dairy farms were the major source of nitrous oxides (from fuel combustion), ammonia, and methane (from manure management and enteric fermentation). Nevertheless, dairy farm activities, which include manure management, enteric fermentation and diesel consumption, make the greatest contributions to the categories of impact considered, with the exception of the abiotic depletion category, contributing to over 70% of the total global warming potential (1021.3 kg CO₂ eq. per tonne of milk), 84% of the total photochemical oxidation potential (0.2 kg C₂H₄ eq. per tonne of milk), 70% of the total acidification potential (20.4 kg SO₂ eq. per tonne of milk), and 41% of the total eutrophication potential (7.1 kg eq. per tonne of milk). The production of concentrates and maize silage are the major contributors to the abiotic depletion category, accounting for 35% and 28%, respectively, of the overall abiotic depletion potential (1.4 Sb eq. per tonne of milk). Based on this LCA case study, we recommend further work to evaluate some possible opportunities to improve the environmental performance of Portuguese milk production, namely: (i) implementing integrated solutions for manure recovery/treatment (e.g. anaerobic digestion) before its application to the soil as organic fertiliser during maize and ryegrass production; (ii) improving manure nutrient use efficiency in order to decrease the importation of nutrients; (iii) diversifying feeding crops, as the dependence on two annual forage crops is expected to lead to excessive soil mobilisation (and related impacts) and to insignificant carbon dioxide sequestration from the atmosphere; and (iv) changing the concentrate mixtures.     

不同工况柴油机排气余热回收系统试验与仿真

基于有机朗肯循环(Organic rankine cycle,ORC)设计了柴油机排气余热回收系统。建立了ORC热力学仿真模型预测系统回收性能,并对某款柴油发动机在有、无ORC作用下分别进行试验,对比了试验数据与仿真结果,验证了模型的有效性。将模型应用于不同工况下,观察不同工质流量对ORC净功率及热效率的影响,结果表明ORC净功率随着转速的增加而增加,不同工况下最大热效率均为12.1%,且对应的工质流量选择区间随着转速的提高而扩大,此区间的确定可为ORC试验时工质流量范围的选择提供参考依据。     

先锋植物沙棘Ⅲ——生活史分析

就沙棘生态习性,应归属r-型生态对策型。沙棘的生活史具两型性(有性和无性繁殖),是对有限资源权衡利用与分配在生命维持-生长-繁殖-扩散上的不均衡结果,是长期自然选择,进化的结果。固氮与克隆生长有利与扩大了r-型生态对策。雌雄异株的进化,避免了近交衰退和提高了沙棘的适合度。沙棘的花序分化受多种同源异型基因调控,而性别决定则受Y性染色体上性基因连锁决定。沙棘繁殖力很高,但衰老较快,是一种生命期(20年左右)较短的灌木。     

锅炉循环水泵机械密封设计探讨

通过IR型热水循环泵轴封结构的更新设计实践，阐述了在水温150℃下机械密封的正确设计方法和组合式密封结构专利技术的优点。实践表明，该组合式密封结构作为锅炉热水循环泵的轴封使用是可行的，可以推广应用。     

红色砒砂岩水泥土干湿循环下力学性能试验研究

为有效利用砒砂岩资源,通过简单加工降低治理成本,达到利用价值,在红色砒砂岩中加入不同掺量的硅酸盐水泥制成砒砂岩水泥土,在不同龄期下进行干湿循环、无侧限抗压强度试验和超景深微观结构观测.结果表明:掺量仅为5%砒砂岩水泥土就可以有效改善砒砂岩遇水溃散的特性;干湿循环5次砒砂岩水泥土抗压强度达到最大,然后趋于平缓,可见干湿循环对无掺水泥砒砂岩有破坏作用,对砒砂岩水泥土却提供了有效养护;不论是早期还是后期强度,掺量为5%的抗压强度最低,然后逐渐增加,掺量20%及以上的强度几乎相等且最大,可见水泥最优掺量为20%;通过微观结构观察,龄期的增加,掺量小的砒砂岩水泥土表面凹凸起伏程度大,孔洞多,最优掺量为20%的砒砂岩水泥土结构整体性紧密,表面平整、孔洞少,密实性更好,且抗压强度可以满足砖和砌块的强度要求.     

电动汽车固定区域行驶工况开发研究

行驶工况对于电动汽车的开发设计有很重要意义。本文以中山大学校区校园SEV中巴行驶工况开发为实例,通过实地调查和采集数据分析,根据固定区域内单一线路行驶车辆具有相似性和周期性特点,提出行驶段来分割原始数据方法。对大量试验数据进行了处理,提取有效行驶段的特征参数,引入主成分分析对特征参数进行压缩,以主成分参数为准则,从行驶段样品挑选出代表性行驶工况。本文提出了一种快速有效行驶工况开发方法,可以用在固定区域如景区、楼盘、学校里有相对固定路线的汽车行驶工况开发。     

基于生态和环境用水安全的调入水规模研究

为实现调水工程受水区可持续发展,以二元水循环规律为基础,从受水区生态和环境用水水量和水质两方面对调水的规模进行了研究,并建立了与其水资源开发利用系数、污水排放率和区域外与区域内用水比例k相关的生态和环境水安全调入水规模计算模型.以郑州市2010年和2020年不同频率年接受南水北调水为例进行计算和综合评价.结果是:①20...