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1.
《International Journal of Hydrogen Energy》2022,47(40):17737-17748
Due to problems such as pores on surface-treated coatings, the corrosion resistance of pure titanium bipolar plates for proton-exchange membrane fuel cells can be further improved by increasing the corrosion resistance of pure titanium by using differential speed-rolling (DSR); however, these materials have not yet reached the standard requirements of bipolar plates (corrosion current density icorr<103 nA·cm?2). In this work, the corrosion resistance of pure titanium was improved by optimizing the DSR process while the strength was maintained. The best corrosion resistance of the DSR pure titanium was achieved when the roller speed ratio was 2, while icorr was 429 nA·cm?2 in a solution of 0.5 M H2SO4 and 2 mg/L HF at room temperature. The formability of the DSR pure titanium for bipolar plates was verified. The optimal holding pressure range was 6.8–7.0 kN. 相似文献
2.
《Journal of the European Ceramic Society》2022,42(5):2429-2440
A ring-on-ring (ROR) test is a prevailing test method for evaluating the equi-biaxial strength of glass materials. However, current ROR test standards limit the strength and size of glass to prevent a nonlinear behavior. In this study, the feasibility of ROR testing for non-standard, high-strength glass, such as tempered or ion-exchanged rectangular glass is investigated. To this end, ROR simulation based on theory and experiment is conducted for thirty non-standard glasses with widths of 100–300 mm and aspect ratios of 1.0–2.0. As a result, the maximum measurable stress was about 215.6 MPa for 100 × 200 mm glass and 481.3 MPa for 300 × 600 mm glass with a 3% deviation, which is well above the strength of regular tempered glass. The main purpose of this work is to understand the range of aspect ratio of horizontal and vertical widths of a glass plate that can be evaluated by the standard ROR test. 相似文献
3.
In this article, two novel kinds of focusing elements as reflectors are analyzed and compared. One is the grooved Fresnel zone plate reflector with continuous phase‐correcting. The other called subzone paraboloid reflector, has the profile that consists of a series of paraboloids. Their diffraction efficiencies and bandwidths are described. The two elements still preserve the advantages of Fresnel zone plates, namely, low profile, high efficiency, and simple fabrication. Two dual‐reflector antennas using the proposed focusing elements as the main reflectors are simulated and the results show that these antennas have good radiation performances. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:101–108, 2015. 相似文献
4.
G. Inglese 《Inverse Problems in Science & Engineering》2019,27(4):439-459
We deal with the mathematical model of the incremental degradation of the internal coating (e.g. a polymeric material) of a metallic pipe in which a fluid flows relatively fast. The fluid drags solid impurities so that longitudinal scratches, inaccessible to any direct inspection procedure, are produced on the coating. Time evolution of this kind of defects can be reconstructed from the knowledge of a sequence of temperature maps of the external surface. The time-varying orthogonal section of this damaged interface is determined as a function of time and polar angle through the identification of a suitable effective heat transfer coefficient by means of Thin Plate Approximation. 相似文献
5.
This paper discusses the compressive performance of perforated brick masonry after fire exposure. Compressive strength tests of the mortar, clay perforated brick, and perforated brick masonry specimens were performed in accordance with ISO834 fire tests of different durations. The temperature distribution of the masonry materials and specimens was simulated using the finite element software ABAQUS, with the thermal parameters of masonry materials recommended by European standard Eurocode 6 and related literature. The compressive strength reduction factors of mortar and clay perforated brick exposed to different fire durations were calculated via the layered method suggested by European standard Eurocode 1. In addition, the compressive strength reduction factors after cooldown were obtained from the experimental data of the masonry materials, and by considering further reductions in the compressive strength after cooling from high temperatures. Experimental data of the masonry specimens were compared with the numerical results obtained using the reduction factors proposed in this work. The comparison revealed an overall acceptable approximation. Thus, the method presented in this paper can be used to evaluate the residual capacity of masonry structures after fire. 相似文献
6.
沉管隧道水下最终接头施工技术初探 总被引:1,自引:0,他引:1
简述了沉管隧道水下最终接头施工技术的应用现状,结合具体隧道工程实例,从外模工程、混凝土结构两方面介绍了最终接头施工技术,表明了该技术具有运用价值。 相似文献
7.
Ph. D. Candidate:Chen Xue-fengState Key Laboratory of Offshore Coastal Engineering Dalian University of Technology Dalian China e-mail: cxfeng @ student dlut. edu.cn 《水动力学研究与进展(B辑)》2003,15(6)
The reflection coefficient of perforated caissons and the total horizontal forces acting on them were experimentally and numerically analyzed and discussed when wave propagates normally. To consider the viscosity effect of fluid and nonlinear action of waves on structures, the VOF (Volume Of Fluid) method combined with the k-ε turbulence model was used to simulate the interaction between waves and structures. Governing equations were solved with the finite difference method. Through 2D experimental study in the wave flume, the empirical relationship between the reflection coefficient of perforated caissons and the main affecting factors were obtained from the experimental data using the least square method. Also the correlation between the ratio of the total horizontal force acting on perforated caisson and the force acting on solid caisson and the main affecting factors were regressed from the experimental data. 相似文献
8.
热镀锌板(卷)工程设计中的环境保护问题 总被引:1,自引:0,他引:1
对热镀锌板(卷)的生产工艺、主要生产设备进行了简要介绍,并就其污染源(工序)、生产过程中产生的污染物及其控制措施进行了评述,同时就设计和生产中宜注意的几个环保问题进行了分析。 相似文献
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