现场总线技术在变电站综合自动化中的应用探讨

对几种常用现场总线的原理及特点做了简要介绍,结合变电站综合自动化,重点分析了LonWorks和CAN 总线在实际配电系统中的应用,最后以FJNT2000 220kV变电站综合自动化系统的具体拓扑为例,分析了LonWorks和CAN 在现场总线中的应用.对现场总线应用行业从业人员具有实际的参考价值.     

管道防腐涂层新发展

综述了国内外管道防腐涂层的应用现状,着重介绍了管道防腐涂层材料与技术的新发展,对管道防腐涂层的发展前景做出了展望。     

Optimization of hybrid – ground coupled and air source – heat pump systems in combination with thermal storage

Ground coupled heat pumps are attractive solutions for cooling and heating commercial buildings due to their high efficiency and their reduced environmental impact. Two possible ideas to improve the efficiency of these systems are decoupling energy generation from energy distribution and combining different HVAC systems. Based on these two ideas, we present several HVAC configurations which combine the following equipments: a ground coupled heat pump, an air to water heat pump and a thermal storage device. These HVAC configurations are linked to an office building in a cooling dominated area in order to evaluate in these conditions the total electrical consumption of each configuration to obtain which one satisfy the thermal demand more efficiently. The results of our simulations show that the electrical energy consumption obtained when the system employs a suitable configuration is of around the 60% compared with an HVAC system driven by an air to water heat pump and around the 82% compared with an HVAC system driven by a ground coupled heat pump.     

中压氮压机喘振故障及其防范措施分析

由于操作不当和原控制系统存在不足,20000 m3/h中压氮压机发生喘振故障而停运。介绍了故障发生经过,分析了原压缩机防喘振系统存在的问题及其改进措施。     

Development of titanium-doped SmBaMn2O5+δ layered perovskite as a robust electrode for symmetrical solid oxide fuel cells

It is a big challenge ahead of finding a symmetric electrode material that optimally works as both anode and cathode, with excellent structural and chemical stability and high catalytic activity. Herein, we propose a high-performance symmetric electrode material, SmBaMn_1.9Ti_0.1O_5+δ (SBMTi), with a single A-site layered perovskite phase in both reducing and oxidizing atmospheres. Owing to the high binding energy, titanium doping can enhance the structural stability and improve the catalytic activity to the hydrogen oxidation and oxygen reduction processes. The simple Ti-doping strategy enables a dramatic reduction in stoichiometric oxygen change upon oxidizing and reducing atmosphere alternation, and a considerable decrease in thermal expansion coefficient. The symmetrical cell with SBMTi electrode can provide a maximum power density of 603 mW cm⁻² at 900 °C, and shows a relatively stable thermal-cycle and atmosphere alternation performance. The developed SmBaMn_1.9Ti_0.1O_5+δ shows great potential as symmetric electrode in symmetrical solid oxide fuel cells.     

钻井液凝胶对波动压力影响模型研究

为了预防起下钻时井涌、井漏等复杂工况发生,需更精确地实时监测井眼压力。以钻井液实时凝胶分解模型为基础,结合钻井液流变特性,建立了基于钻井液触变特性的动态波动压力计算模型。分析认为,井筒工况改变时,凝胶强度破坏对压力激增影响程度大,并结合实验对比,验证了该模型的可行性和准确性。研究结果表明,该模型能精确地实现钻井中井眼压力实时监测与预警作用,具有良好实用价值。     

低温空气源热泵供热方式在北方供暖地区的适宜性研究

低温空气源热泵作为高效、清洁的供热方式日益受到关注。为分析低温空气源热泵供热方式在北方寒冷地区居住建筑中的应用适宜性,本文以北京地区的居住建筑为研究对象,采用模拟分析的方法,比较研究低温空气源热泵供热方式与北方地区传统供热方式在一次能源消耗、二氧化碳排放量、初投资及运行费用等方面的差异。相对传统供热方式,在适宜应用的场合,低温空气源热泵供热方式具有明显的节能及环保优势。     

某井油管脱扣原因分析

针对某井用Φ88.9mm×6.45mm P110钢级NU油管脱扣事故进行深入调查研究,对脱扣的油管进行了宏观和微观形貌分析,对油管材质进行了理化性能试验,对该批次未使用的油管接头试样进行了参数测量。通过试验分析和研究,认为油管接头材质及螺纹参数符合标准要求,油管脱扣属于低载荷滑脱失效,滑脱失效的主要原因是由于粘扣和上扣不到位导致接头的连接强度大幅度降低造成,而粘扣和上扣不到位的主要原因是上扣过程中发生了错扣。     

Dynamic performance of a façade-based solar loop heat pipe water heating system

This paper reported a dedicated study of a novel façade-based solar loop heat pipe (LHP) water heating system using both theoretical and experimental methods. This system employs a modular panel incorporating a unique loop heat pipe that is able to serve as part of the building façade or a decoration layer of the façade, thus creating a façade integrated, low cost, highly efficient and aesthetically appealing solar water heating structure. Taking into account heat balances occurring in different parts of the system, e.g., solar absorber, heat pipes loop, heat exchanger and storage tank, a dedicated computer model was developed to investigate the dynamic performance of the system. An experimental rig was also established to evaluate the performance of such a prototype system through measurement of various operational parameters, e.g., solar radiation, temperatures and flow rates of the heat pipe fluid and water. Through comparison between the testing and modelling results, the model has been approved to be able to give a reasonable accuracy for predicting the performance of the LHP system. Two types of glass covers, i.e., double glazed/evacuated tubes and single-glazing plate, were applied to the prototype. It was found that for both covers, the heat pipe fluid temperature rose dramatically at the start-up operation and afterwards remained a slow but steady growth; while the water temperature remained a steadily growing trend throughout the operational day. The temperature rise of the circulated water at 1.6 l/min of flow rate was around 13.5 °C in the double-glazed/evacuated tubes based system and 10 °C in the single-glazing based system; correspondingly, their average solar conversion efficiencies were 48.8% and 36%, and the COPs were 14 and 10.5 respectively. In overall, the double-glazed/evacuated tubes based system presented a better performance than the single glazing based one.     

The impact of data base management systems (DBMS) standardization on auditing

Auditing becomes increasingly difficult in a data base environment. Data base management systems standardization efforts, both nationally and worldwide, are significant advances for auditing, but so far they offer only partial solutions to the auditor's difficulties. The enterprise view of data and the International Standards Organization's (ISO) emphasis on the conceptual schema are applied to the audit environment. The findings suggest that auditors must become involved in the standardization discussions and in further attempts to define requirements for a special audit schema.