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101.
Sr2−xLaxMnO4+δ (x = 0.4, 0.5, 0.6) oxides were studied as the cathode material for solid oxide fuel cells (SOFC). The reactivity tests indicated that no reaction occurred between Sr2−xLaxMnO4+δ and CGO at annealing temperature of 1000 °C, and the electrode formed good contact with the electrolyte after being sintered at 1000 °C for 4 h. The total electrical conductivity, which has strong effect on the electrode properties, was determined in a temperature range from 100 to 800 °C. The maximum value of 5.7 S cm−1 was found for the x = 0.6 phase at 800 °C in air. The cathode polarization and AC impedance results showed that Sr1.4La0.6MnO4+δ exhibited the lowest cathode overpotential. The area specific resistance (ASR) was 0.39 Ω cm2 at 800 °C in air. The charge transfer process is the rate-limiting step for oxygen reduction reaction on Sr1.4La0.6MnO4+δ electrode. 相似文献
102.
This paper presents an optimization approach applied to a whole fuel cell (FC) air supply system including its geometry and its control. The aim is to optimize its power consumption along with its mass. Particle swarm optimization (PSO) algorithm is used to define the design parameters of both permanent magnet synchronous motor (PMSM) and a fuzzy logic controller (FLC). The results are compared with those obtained by a sequential optimization process and advantages of co-design optimization approach are clearly shown. Indeed, a significant reduction of the objective function (made up on both motor mass and energy consumption) on a considered operating cycle can be obtained. 相似文献
103.
Electrical characterization analyses are proposed in this work using the Lambert function on Schottky junctions in GaN wide band gap semiconductor devices for extraction of physical parameters. The Lambert function is used to give an explicit expression of the current in the Schottky junction. This function is applied with defined conduction phenomena, whereas other work presented arbitrary (or undefined) conduction mechanisms in such parameters'' extractions. Based upon AlGaN/GaN HEMT structures, extractions of parameters are undergone in order to provide physical characteristics. This work highlights a new expression of current with defined conduction phenomena in order to quantify the physical properties of Schottky contacts in AlGaN/GaN HEMT transistors. 相似文献
104.
O. Latry P. Dherbécourt K. Mourgues H. Maanane J.P. Sipma F. Cornu P. Eudeline M. Masmoudi 《Microelectronics Reliability》2010,50(9-11):1574-1576
A reliability test bench dedicated to RF power devices is used to improve 330 W LDMOS in a radar conditions. The monitoring of RF power, drain, gate voltages and currents under various pulses and temperatures conditions are investigated. Numerous duty cycles are applied in order to stress LDMOS. It shows with tracking all this parameters that only few hot carrier injection phenomenon appear with no incidence on RF figures of merit (Pout or PAE). Robustness and ruggedness are shown for LDMOS with this bench for radar applications in L-band. 相似文献
105.
106.
The introduction of competition into retail electricity supply gave rise to great expectations. However, to date, its performance has proven less than stellar, owing primarily to the theoretical concepts underpinning this reform, which draw heavily on the Austrian school. Neither consumers’ decision processes nor this sector's technical paradigm were adequately accounted for, leading to an uncorrect estimation of the expected impact of opening to competition. Short- and medium-term prospects for the evolution of retail markets must be reconsidered from the perspective of greater stability: not a generalization of competition, but rather a persistent segmentation between active and inactive clients; not a large and rapid diffusion of radical innovations in commercialisation, with the potential for undermining the incumbents’ positions. 相似文献
107.
Christophe Basso 《电子设计应用》2009,(6)
在此前一系列的3篇文章中,指出了如何采用TL431来实现1类和2类补偿器。如果前述补偿器类型适合大多数电流模式控制配置工作,其它控制模式则可能需要3类补偿器。举例来说,如果需要对连续导电模式(CCM)电压模式转换器进行补偿,就需要额外的极点和零点。在这3类配置中,TL431并不太有利于实践这样的设计:眼前的快通道(fast lane)显然会使设计工作复杂化。本文提出了简单的构想,以与所观测到交流输入完全解耦的外部直流偏置来消除快通道。这样一来,设计工作被简化,类似于采用运放来构建传统的3类补偿器。 相似文献
108.
Laurent Mezeix Christophe Bouvet Julitte Huez Dominique Poquillon 《Journal of Materials Science》2009,44(14):3652-3661
Entangled fibrous materials have been manufactured from different fibers: metallic fibers, glass fibers, and carbon fibers.
Specimens have been produced with and without cross-links between fibers. Cross-links have been achieved using epoxy spraying.
The scope of this article is to analyze the mechanical behavior of these materials and to compare it with available models.
The first part of this article deals with entangled fibrous materials without cross-link between fibers. Compression tests
are detailed and test reproducibility is checked. In the second part, compression tests were performed on materials manufactured
with cross-linked fibers. The specific mechanical behavior obtained is discussed. 相似文献
109.
Christos Baloukas Author Vitae Jose L. Risco-Martin Author Vitae Christophe Poucet Author Vitae Lazaros Papadopoulos Author Vitae Juan Lanchares Author Vitae 《Journal of Systems and Software》2009,82(4):590-602
Modern multimedia application exhibit high resource utilization. In order to efficiently run this kind of applications in embedded systems, the dynamic memory subsystem needs to be optimized. A key role in this optimization is played by the dynamic data structures that reside in every real-life application. This paper presents a novel and automated way to optimize dynamic data structures. The search space is pruned using genetic algorithms that converge to the best multilayered data structure implementation for the targeted applications. 相似文献
110.
We present a manufacturing method based on the dynamic use of phase plates to photowrite Bragg gratings. This process allows for control of the local value of the index modulation envelope in the grating. The application to apodized fiber Bragg gratings is discussed. 相似文献