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91.
Jesús Canales-Vázquez Juan Carlos Ruiz-Morales David Marrero-López Juan Peña-Martínez Pedro Núñez Pedro Gómez-Romero 《Journal of power sources》2007
In the work presented herein, the potential use of La4Sr8Ti12−xFexO38−δ (LSTF) materials as electrodes for a new concept of solid oxide fuel cells, symmetrical fuel cells (SFCs), is considered. Such fuel cells use simultaneously the same material as anode and cathode, which notably simplifies the assembly and further maintenance of the cells. Therefore, we search for materials showing high conductivity in a wide range of oxygen partial pressures in addition to certain degree of catalytic activity for the oxidation of the fuel and reduction of the oxidant, respectively. The preliminary electrochemical experiments performed reveal that the overall conductivity increases notably upon Fe substitution, being the main contribution electronic n-type. The fuel cell tests indicate that LSTF composites with YSZ and CeO2 perform reasonably well under H2 conditions, although the performance in methane is rather modest and require further optimisation. 相似文献
92.
93.
Precise timing and asynchronous I/O are appealing features for many applications. Unix kernels provide such features on a per‐process basis, using signals to communicate asynchronous events to applications. Per‐process signals and timers are grossly inadequate for complex multithreaded applications that require per‐thread signals and timers that operate at finer granularity. To respond to this need, we present a scheme that integrates asynchronous (Unix) signals with user‐level threads, using the ARIADNE system as a platform. This is done with a view towards support for portable, multithreaded, and multiprotocol distributed applications, namely the CLAM (connectionless, lightweight, and multiway) communications library. In the same context, we propose the use of continuations as an efficient mechanism for reducing thread context‐switching and busy‐wait overheads in multithreaded protocols. Our proposal for integrating timers and signal‐handling mechanisms not only solves problems related to race conditions, but also offers an efficient and flexible interface for timing and signalling threads. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
94.
着重介绍了静态法测试低温下(-100~50℃)液体饱和蒸气压的原理及方法,给出了低温下液体全氟三乙胺饱和蒸气压的测试结果,并进行了讨论。 相似文献
95.
Vicente Ferreira Cristina Peña Ana Escudero Juan Cacho 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1996,202(4):318-323
The ability of fermentative CO2 to blow off the volatile compounds that are synthesized during fermentation has been studied. Model solutions simulating a fermenting must were purged at different CO2 flow rates and temperatures, and the amount of volatile compounds blown off by the stream of CO2 was recorded by high-resolution gas chromatography. Data showed that under normal fermenting conditions, fatty acid ethyl esters and some fusel alcohol acetates are blown off the solution at a high rate. The maximum loss rate was observed for ethyl decanoate. The purging speed is doubled when temperature increases from 17 °C to 27 °C. Losses can be interpreted by a linear model and are a function of the compound and the flow rate of CO2. These models allow us to reconstruct the volatile synthesis vs time functions through graphic calculus and to estimate the proportion of volatile material retained, hydrolysed and purged. Synthesis takes place during the tumultuous period of fermentation together with CO2 production that blows off the volatile material. Hydrolysis takes place in the last stages of fermentation. In a 10-1 open fermenter, up to 80% of volatile material can be blown off while an average of 10% is retained. Residual esterase activity accounts for about 20% of the total amount of ester synthesized. 相似文献
96.
Víctor Osma-Ruiz Juan I. Godino-Llorente Pedro Gómez-Vilda 《Pattern recognition》2007,40(3):1078-1090
The present paper describes a new algorithm to calculate the watershed transform through rain simulation of greyscale digital images by means of pixel arrowing. The efficiency of this method is based on limiting the necessary neighbouring operations to compute the transform to the outmost, and in the total number of scannings performed over the whole image. The experiments demonstrate that the proposed algorithm is able to significantly reduce the running time of the fastest known algorithm without involving any loss of efficiency. 相似文献
97.
This paper studies the input-output finite-time stabilization problem for time-varying linear singular systems. The output and the input refer to the controlled output and the disturbance input,respectively.Two classes of disturbance inputs are considered,which belong to L-two and L-infinity.Sufficient conditions are firstly provided which guarantee the input-output finite-time stability.Based on this,state feedback controllers are designed such that the resultant closed-loop systems are input-output finite-time stable.The conditions are presented in terms of differential linear matrix inequalities.Finally,an example is presented to show the validity of the proposed results. 相似文献
98.
面向软件动态演化的需求建模及其模型规范化 总被引:2,自引:0,他引:2
针对目前需求工程阶段对软件动态演化考虑不足的现状,在分析软件动态演化面临的挑战的基础上,设计了面向动态演化的需求元模型(dynamic-evolution-orientedrequi rements meta-model,DERM)。该元模型以特征为基本部件,按特征组合的方式建立需求模型,需求模型由行为特征和属性特征组成。行为特征被区分为计算行为特征和交互行为特征,以实现计算和交互的相对隔离;属性特征通过其作用域,指定其在行为特征模型中的作用范围,从而将行为特征模型和属性特征模型统一为需求模型。在此基础上,讨论了需求模型的参照完整性、依赖一致性和互斥一致性,并进一步把需求模型规范化为需求模型第一范式到第三范式,需求模型规范化的过程提供了一种保证需求模型一致性的方法。最后通过案例研究,表明了该方法的可行性及其对软件动态演化的有效支持。 相似文献
99.
100.
By analysis of the basic properties of entanglement swapping of high-dimensional Bell states,a universal and general deterministic secure quantum communication(DSQC)protocol is proposed,in which unitary operation is not required.By making use of the results of high-dimensional Bell measurement,the sender and the receiver can encode and decode the message respectively by performing the modular addition and subtraction.Two mutually complementary bases are constructed;and according to the property of mutual complement,a method for checking security of the high-dimensional quantum channel is put forward.Some common attack strategies are analyzed,and the corresponding error rates are calculated.Then the upper bound of the threshold of error rate is deduced. 相似文献