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101.
102.
103.
Electrical contact resistance between stainless steel bipolar plate and carbon felt in PEFC: A comprehensive study 总被引:1,自引:0,他引:1
Johan André Laurent Antoni Jean-Pierre Petit Eric De Vito Alexandre Montani 《International Journal of Hydrogen Energy》2009
Bipolar plate represents a key component of Proton Exchange Membrane Fuel Cell (PEFC) with several essential functions, among them the electric connection of elementary cells. Usually made of graphite, this component is studied worldwide in order to develop a commercially viable alternative: different ways have been being investigated, and to date, despite corrosion issues, stainless steel (SS) appears as a good candidate material, but its Electrical Contact Resistance (ECR) can reach unacceptable values when exposed to PEFC environment. This paper offers a comprehensive study of the parameters acting on ECR when using uncoated SS in PEFC: roughness, which influences the surface contact area with carbon baking, bulk composition of the alloy, which influences only partly the nature of passive films, and the composition and structure of passive films, strongly modified by surface treatments and ageing conditions. 相似文献
104.
105.
Michael G. Debije Jean-Pierre Teunissen Paul P.C. Verbunt 《Solar Energy Materials & Solar Cells》2009,93(8):1345-1350
The effect of adding white scattering layers to the bottom side of luminescent solar concentrator waveguides is evaluated. It is determined that adding a rear scatterer separated from the waveguide by an air gap results in a large increase of energy output from the waveguides, and this enhancement persists over long (>30 cm) distances, although the magnitude of the enhancement decreases with distance. An attached scatterer resulted in the greatest improvement of light output for short (∼6 cm) distances, but actually reduced edge emissions over longer distances. We provide estimates for the relative contribution of dye-emitted light and scattered light to the total waveguide emission, as well as distinguishing between the contributions of direct and indirect scattering of light to the total output as a function of dye content of the waveguides. 相似文献
106.
The textural characteristics of three commercial activated carbons, Filtrasorb 400 (F400), Industrial React High Affinity
and Picabiol, commonly used in water treatment, are reinvestigated. Nitrogen physisorption isotherms are determined in the
range P/P
0 = [4 × 10−7–0.998] and processed using BET, αS (Sing), Dubinin–Radushkevich and Density Functional Theory methods. In addition, fractal dimensions are determined by the
Frenkel–Halsey–Hill procedure. Since F400 is often considered as a reference material in studies on the adsorption of solutes
in aqueous solutions, a review of the textural characteristics of this carbon is carried out. The results obtained in this
work using the different methods are consistent and a critical crossed comparison of these results allows discussing the limitations
of the methods used. In particular, the impact of the P/P
0 range considered on S
BET value is examined. In addition, the accuracy of the BET specific surface area is assessed in the light of information from
recent literature. 相似文献
107.
This paper deals with a well-known problem in the general area of search theory: optimize the search resources sharing so as to maximize the probability of detection of a (moving) target. However, the problem we consider here considerably differs from the classical one. First, there is a bilevel search planning and we have to consider jointly discrete and continuous optimization problems. To this perspective original methods are proposed within a common framework. Furthermore, this framework is sufficiently general and versatile so as to be easily and successfully extended to the difficult problem of the multizone multisensor search planning for a Markovian target. 相似文献
108.
Magalie Laniel Jean-Pierre Emond Ahmet E. Altunbas 《Sensing and Instrumentation for Food Quality and Safety》2009,3(1):34-40
The performance of radio waves in open environments has been studied for years. In contrast, the behavior of Radio Frequency
Identification (RFID) inside metal enclosed areas is not yet understood. This research project focuses on the 3-D mapping
of RFID signal strength inside a 12 m refrigerated marine container instrumented with three different types of radio frequency
(RF) emitters: 915 MHz reader; 2.45 GHz reader and 433 MHz RF transmitter. The main goal is to find a frequency/configuration
that would allow real time reading of the temperature in a shipment of perishable products using RFID. Only one frequency
and one antenna were used at a time. The RF transmitter antenna was mounted at two different places inside the container;
at the top of the front wall (facing back) and on the ceiling in the middle of the container (facing down). The signal strength
was acquired by a spectrum analyzer and its antenna was mounted on a small electric cart inside the container. The cart was
programmed to move along the length of the container and stop repeatedly, allowing three automated measures per position.
All data were analyzed in terms of power level and attenuation. The maps showed that the RFID antenna positioned at the front
of the container delivered slightly better results than the one in the middle of the ceiling. The results showed a significantly
higher performance at the 433 MHz level.
This article was presented at Food Processing Automation Conference, American Society of Agricultural and Biological Engineering
(ASABE), Providence, RI, June 28–29 2008. 相似文献
109.
Andrea Kaiser Katja I. Hartmann Dietmar R. Kammerer Reinhold Carle 《European Food Research and Technology》2013,237(3):353-365
Initial heating was applied as the first processing step in the production of innovative pasty celeriac products. For this purpose, celeriac was converted into a paste and subsequently heated at 90 and 100 °C for 5–10 min. Alternatively, the fresh plant material was blanched prior to mincing. For the first time, phenolic compounds in celeriac were characterized by high-performance liquid chromatography coupled with mass spectrometry (LC–MSn). Among the 14 phenolics detected, several caffeic, ferulic and quinic acid derivatives as well as malonylated and acetylated flavonoid derivatives were newly identified. Upon thermal treatment, the antioxidant capacities (TEAC assay) and the total phenolic contents remained virtually unchanged. The antioxidant capacities of heated samples determined by the FRAP assay were even higher than those of the unheated control. The contents of the main phenolic compound apiin decreased upon heat treatment, whereas the levels of the minor compounds malonylapiin A and B increased. Only by extended steam- and water-blanching at 100 °C, respectively, complete inactivation of peroxidase and polyphenol oxidase was achieved. The obtained celeriac products were characterized by their bright white color. Consequently, blanching is recommended as the initial operation in the processing of celeriac into novel pasty products. 相似文献
110.
Shaoying Lu Michailova A. Saucerman J. Yuhui Cheng Zeyun Yu Kaiser T. Li W. Bank R. Holst M. Mccammon J. Hayashi T. Hoshijima M. Arzberger P. McCulloch A. 《IEEE engineering in medicine and biology magazine》2009,28(2):46-57
This paper indicates that in ventricular myocytes when the SR (sarcoplasmic reticulum) is pharmacologically inhibited, the intracellular Ca2+concentration rapidly increases during Ca2+ entrance (0-70 ms), whereas the decay of Ca2+ is slow; in the absence of fluorescent dye, large Ca2+ concentration gradients might develop near the cell membrane; intracellular Ca2+ distribution is tightly regulated by the localization of Ca2+transporter proteins along the sarcolemma and strongly relays on the presence of mobile and stationary Ca2+ buffers. These studies also imply that in ventricular cells with intact and functional SR, the Ca2+ signal most likely would spread faster along the t-tubular system, surface membrane than to the cell interior and that in the absence of Ca2+ dye high Ca2+ gradients under the surface membrane and more uniform Ca2+ distribution in the cell interior might be expected. 相似文献