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941.
Saurabh A. Vilekar 《Journal of power sources》2010,195(8):2241-2247
Even though the measured open-circuit voltage in a H2-O2 PEM fuel cell is invariably about 200-250 mV lower than that predicted from thermodynamics (1.229 V at 25 °C), there is no unequivocal explanation of this phenomenon available in the literature, although several hypotheses exist. Based on a theoretical model of mixed potential with a priori parameters, it is shown here that this voltage loss under open-circuit conditions can be attributed exclusively to hydrogen crossover and the resulting oxygen reduction reaction overpotential at the cathode. The analytical model predictions agree well with available experimental results. 相似文献
942.
943.
R. B. Salikhov A. N. Lachinov R. G. Rakhmeev R. M. Gadiev A. R. Yusupov S. N. Salazkin 《Measurement Techniques》2009,52(4):427-431
A procedure is described for formation of a nano-structured organic-organic interface with increased conductivity at the interface
of two polymer films. It is established that conductivity is determined by the type and degree of external action. It is shown
that on the basis of this interface it is possible to create chemical sensors, and in fact sensors for the relative humidity
of air, ethanol vapor pressure, and pH readings.
Translated from Izmeritel’naya Tekhnika, No. 4, pp. 62–64, April, 2009. 相似文献
944.
Thirty Lactobacillus isolates from artisanal Manchego cheeses, 10 belonging to Lactobacillus plantarum and 20 belonging to Lactobacillus paracasei subsp. paracasei, were examined for potential use as adjunct cultures. Isolates were screened for acidifying and amino-biogenic capacity, for proteolytic, lipolytic, autolytic and aminopeptidase activities, and for sensory characteristics in UHT coagulated milk. Most of the lactobacilli displayed high aminopeptidase and autolytic activities and low acidifying activity. Only one isolate was able to produce tyramine. When growing on milk 53.3% of the Lb. paracasei subsp. paracasei isolates were able to produce pleasant flavours. Strains PBL210 (Lb. plantarum) and PBL213 and PBL226 (Lb. paracasei subsp. paracasei) presented the best technological characteristics, and also were still viable and with unaltered properties after freeze-drying and storage for 12 months. For these reasons, these strains could be good candidates for inclusion as adjuncts in a starter culture to manufacture industrial Manchego cheese. 相似文献
945.
In today's digital electronic integrated circuits device heating is one of the most critical issues. Overheating can cause failures in functionality and device malfunction. In certain circumstances overheating of ICs can cause physical destruction of the device itself. This paper introduces a solution to determine cell and gate heating curves across the standard cell IC's surface. The presented methodology and toolset is tightly integrated into standardized logic simulator engines thus providing digital circuit designers a low-level, cell-resolution temperature distribution map during logic simulations. Actual temperatures of each consisting cell of the design can be monitored throughout the whole logic simulation. By being able to monitor temperatures of digital cells during initial simulations, it allows us to detect hot-spots and overheating caused malfunctions far before manufacture. By using the spatial location and temperature magnitude of hot-spots acquired from the presented methodology, place and route (P&R) tools can be driven to change cell placement and routing in order to avoid heating caused failures. Additionally, cooling solutions can be developed using the simulated temperature maps of the IC's surface. This paper also presents various aspects of power characterization methods which were used throughout the experiments. 相似文献
946.
947.
948.
949.
超细分子筛的合成和应用 总被引:5,自引:0,他引:5
综述了近年来超细沸石分子筛的合成及其结构-性能表征方面的进展,并简介超细分子筛材料在催化领域中的应用。 相似文献
950.
Minghui Chen Shenglong Zhu Mingli ShenFuhui Wang Yan Niu 《Materials Science and Engineering: A》2011,528(3):1360-1366
NiCrAlY platelets modified glass matrix composites were prepared. Their microstructures were characterized, their Young's modulus, fracture strength in bending, Vickers hardness, and indentation toughness were measured, and their thermal shock resistance was studied using quenching-strength and indentation-quench methods. With increasing NiCrAlY content, evident enhancements of the Young's modulus and indentation toughness were obtained. The NiCrAlY alloy inclusion could exert significant influences on the retained bending strength of the samples after quench tests, from 9.6 MPa for NiCrAlY-free glass to 32.0 MPa for 30 wt.% NiCrAlY-containing composites. The indentation-quench tests showed that NiCrAlY alloy inclusion elevated the critical quenching temperatures for propagation of pre-crack, from 150 °C for NiCrAlY-free glass to 225 °C for 30 wt.% NiCrAlY-containing composites. Inclusion debonding and intersection, crack deflection and bridging were observed, and are likely the micromechanisms accounted for the improvement of fracture resistance. 相似文献