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101.
The macro-homogeneous porous electrode theory is used to develop a model which describes the catalyst layer of the hydrogen electrode formed by catalyst particles that are bonded to the membrane. The water transport in the catalyst layer and polymer electrolyte membrane is considered. The effects of catalyst layer structure parameters such as polymer volume fraction, catalyst layer thickness, platinum loading and reactant gas humidity as well as CO poison on the hydrogen electrode behavior are examined. The results show that the catalyst layer thickness has a significant effect on the electrode performance. A thicker catalyst layer will result in a larger ohmic voltage loss and higher catalyst cost. The optimal polymer volume fraction and catalyst layer thickness are 0.5 and 1.5–4 μm, respectively, for this electrode. An optimal platinum surface coverage on carbon need not exceed 20% (20 wt% Pt/C). Larger platinum coverage will increase the cost, but only slightly enhance the electrode performance. 相似文献
102.
Pre- and/or post-compensators are designed to square down a general MIMO system to a uniform rank system, the structure of which is almost similar to a SISO system. The method of squaring down either does not change the finite zero structure of the given MIMO system or simply adds additional finite zeros in the left half s-plane. The significance of such a squaring down lies in the simplicity of the structure of a uniform rank system lending itself for easy analysis and control design. 相似文献
103.
Invertible Bloom Lookup Tables (IBLTs) have been recently introduced as an extension of traditional Bloom filters. IBLTs store key-value pairs. Unlike traditional Bloom filters, IBLTs support both a lookup operation (given a key, return a value) and an operation that lists out all the key-value pairs stored. One issue with IBLTs is that there is a probability that a lookup operation will return “not found” for a key. In this paper, a technique to reduce this probability without affecting the storage requirement and only moderately increasing the search time is presented and evaluated. The results show that it can significantly reduce the probability of not returning a value that is actually stored in the IBLT. The overhead of the modified search procedure, compared to the standard IBLT search procedure, is small and has little impact on the average search time. 相似文献
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107.
Gemini表面活性剂的结构特点及在采油中的应用 总被引:2,自引:0,他引:2
文章简要地介绍了Gemini表面活性剂的结构特点;从表面活性剂的作用原理出发,介绍了Gemini表面活性剂的优良性能:如表面张力、泡沫力、润湿力、优异的协同效应、耐温抗盐性等;在此基础上,阐述了该类表面活性剂在油田三次采油上的应用前景。 相似文献
108.
The effect of the processing molding temperature on the properties and crystalline structure of acrylonitile‐butadiene rubber (NBR)/nylon 6,66,1010 (trinylon) thermoplastic vulcanizates (TPV) was studied. With decreasing molding temperature, the stress at 100% and elongation at break of TPV changed slightly, and the solvent resistance of TPV improved. The best conditions for processing molding were 170°C and 12 min. The crystalline structure of the nylon continuous phase in TPV was investigated by X‐ray diffraction, polarized optical microscopy, and differential scanning calorimetry. The results show that the crystalline structure of the nylon phase in TPV was more perfect/orderly and formed α‐crystalline structure at a processing molding temperature of 170°C. Therefore, the oil resistance of NBR/trinylon TPV clearly improved. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 1374–1379, 2006 相似文献
109.
Wei Wu 《Chemical engineering science》2003,58(15):3565-3570
Experiment was conducted on the threshold pressure for atmospheric air through unconsolidated narrow size distributed mini sphere and sand particles at low flow rates. The threshold diameter calculated from measured threshold pressure showed that it does not follow the traditional similarity theory. This is consistent with our experiment on accurate permeability measurement, and can be explained as a result of gas slip flow within such micro pore structure. Our current work tend to find the method to predict the permeability-threshold pressure relationship for unconsolidated porous structures. 相似文献
110.
Hiroya Nakata Takayoshi Kiguchi Osamu Hino 《Journal of the American Ceramic Society》2022,105(4):2791-2803
To understand the role of phosphate ester dispersant, we investigated the rheology of a BaTiO slurry. For the model case, a coarse-grain molecular dynamics (CGMD) simulation was performed with the butyral polymer didodecyl hydrogen phosphate (DHP) in the toluene/ethanol solvent. By systematically analyzing the effect of DHP from an atomic-scale first principle and from all-atom MD to microscale CGMD simulation, we investigated how the adsorption of a DHP dispersant on a BaTiO surface affects the microstructure rheology of a BaTiO slurry. The first-principle and all-atom MD simulation suggests that DHP molecules prefer to locate near the BaTiO surface. CGMD simulation shows a reduction in viscosity with an increase in dispersants, suggesting that the dispersant population near the BaTiO surface plays a key role in controlling the rheology of the BaTiO slurry. In this study, we propose an approach for understanding the BaTiO slurry with molecular-level simulations, which would be a useful tool for efficient optimization of slurry preparation. 相似文献