High temperature transport kinetics in heteroepitaxial LaFeO3 thin films

Heteroepitaxial LaFeO₃(1 1 0) thin films with a thickness of 150 nm were grown on LaAlO₃(0 0 1) by reactive sputtering in an inverted cylindrical magnetron geometry. Equilibrium conductivity was measured as a function of partial pressure of oxygen at T=1000 °C, and logσ plotted vs. logP(O₂) showed a minimum in conductivity for P(O₂)=10⁻¹¹ atm and a linear response between 10⁻¹⁰ and 1 atm. This linear response makes thin films of LaFeO₃ a promising material for oxygen sensor applications. We have also measured the time response of the film conductivity upon an abrupt change in the partial pressure of ambient oxygen from 10⁻² to 10⁻³ atm, which was determined at 60 s for T=700 °C and <3.5 s at T=1000 °C.     

驻极体声传感器及其储电材料的现状

综述了驻极体声传感器及其储电材料近年来的迅猛发展。传统的FEP(tetrafluoroethylene—hexa—fluoropropylene copolymer)极体电容式声传感器及以铁电聚合物PVDF(poly vinylidene fluoride)家族为芯片的声传感器和超声抉能器仍焕发着青春活力。Si基微型驻极体声传感器的理论和实验研究已经日趋成熟，而用空间电荷型多孔聚合物驻极体压电薄膜为芯片可望研制出新一代声电和电声传感器、压力传感器和驱动器。     

乳化液浓度自动检测配比系统

本文论述了乳化液浓度自动检测配比系统。文章给出了阻容型浓度、液位传感器的原理、结构和测试电路，以及实现乳化液浓度自动检测与自动配比的系统硬件和软件。系统样机通过了型式试验、防爆和工业性试验。研究结构表明，本系统性能优良，达到了煤矿监控产品技术标准，对提高煤机械自动化程度具有重要意义，推广应用前景广阔。     

无基坑轨道衡的研究

本文对无基坑轨道衡的开发与研制,进行了可行性研究。     

十三陵蓄能电站上水库自动监测系统的设计及运行

由于十三陵蓄能电站上水库地处蟒山之巅，所在山体地质条件复杂。施工期埋设了大量的监测仪器，原有人工监测系统效率低、资料分析的同步性差。2002年5月，对其进行了自动化改造，现已有一套符合其特点的自动化监测系统。十三陵上水库水工建筑自动监测系统已正常运行了三年，同时也存在着问题，有待于进一步的探讨和改进。     

Development of cable fault location method using fiber optic distributed temperature sensor

When ground-fault problems occur on a cable line, immediate fault location and restoration are required. Therefore, various new methods to locate the fault point instantaneously have been investigated to replace such conventional methods as the Murray loop method and the pulse radar method [1]. These methods require a long time to locate the fault point. One possible fault location method is to sense the temperature rise following a ground fault using a fiber optic distributed temperature sensor. Application of this method was found feasible through sensing the temperature rise at a ground-fault test using a thermocouple as a temperature sensor with test cables [4]. A power/optical composite cable was prepared experimentally and after verifying its thermal mechanical performance, the temperature rise at an incidence of a fault was determined and the anticipated performance was demonstrated in a ground-fault test. This article describes the outline of the test.     

一种用于强振环境的转速传感器

该文介绍一种简单、可靠、小巧的转速传感器。它的特点是在强振环境下仍具有很高的可靠,可用于坦克底盘、重型工程机械,燃气轮机组等机械作为转速监测。     

Surveillance test policy optimization through genetic algorithms using non-periodic intervention frequencies and considering seasonal constraints

In order to maximize systems average availability during a given period of time, it has recently been developed a non-periodic surveillance test optimization methodology based on genetic algorithms (GA). The fact of allowing non-periodic tests turns the solution space much more flexible and schedules can be better adjusted, providing gains in the overall system average availability, when compared to those obtained by an optimized periodic test scheme. This approach, however, turns the optimization problem more complex. Hence, the use of a powerful optimization technique, such as GA, is required.Considering that some particular features of certain systems can turn it advisable to introduce other specific constraints in the optimization problem, this work investigates the application of seasonal constraints for the set of the Emergency Diesel Generation of a typical four-loop pressurized water reactor in order to planning and optimizing its surveillance test policy. In this analysis, the growth of the blackout accident probability during summer, due to electrical power demand increases, was considered. Here, the used model penalizes surveillance test interventions when the blackout probability is higher.Results demonstrate the ability of the method in adapting the surveillance test policy to seasonal constraints. The knowledge acquired by the GA during the searching process has lead to test schedules that drastically minimize test interventions at periods of high blackout probability. It is compensated by more frequent redistributed tests through the periods of low blackout probability in order to improve on the overall average availability at the system level.     

An economic and environmental assessment of biomass utilization in lignite‐fired power plants of Greece

The environmental and socio‐economic impacts of biomass utilization by co‐firing with brown coal in an existing thermoelectric unit in Greece or through its pure combustion in a new plant were studied and evaluated in this work. The 125 MW_e lignite‐fired power plant in Ptolemais Power Station (Western Macedonia) was used as reference system. The environmental benefits of the alternative biomass exploitation options were quantified based on the life cycle assessment methodology, as established by SETAC, while the BIOSEM technique was used to carry out socio‐economic calculations. The obtained results showed clear environmental benefits of both biomass utilization alternatives in comparison with the reference system. In addition, co‐firing biomass with lignite in an existing unit outperforms the combustion of biomass exclusively in a new plant, since it exhibits a better environmental performance and it is a low risk investment with immediate benefits. A biomass combustion unit requires a considerably higher capital investment and its benefits are more evident in the long run. Copyright © 2005 John Wiley & Sons, Ltd.     

Photovoltaic collectors efficiency according to their integration in buildings

A model for building integrated photovoltaic systems has been developed and implemented in a dynamic simulation tool. This tool takes into account the thermal interactions between the PV collector and the building. The influence of the type of integration upon the PV collector efficiency has been evaluated and hybrid PV/air collectors have been studied. An overall efficiency is defined, including the production of electricity and heat. A case study has been performed on two different typical buildings. In the case of a multi-crystalline silicon PV collector integrated on the roof of a single family house located in Paris, the efficiency of unventilated PV modules fixed on the roof is 14%. If the PV collector is used to preheat the ventilation air, the efficiency reaches 20%. A proper building integration also improves the environmental balance of PV technologies over their life cycle.