D.P. Tao(Department of Metallurgy
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Kunming University of Science and Technology
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Kunming 650093
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China)
金属学报(英文版)
A fractal pore diffusion model of fiuidS in porous media which is in good agreement with the experimental data of the coke-CO2 reaction, has been derived by using the Mandelbrot's fractal length-area relation. Based on the model, a new formula and its interpretation about the tortuosity of pore structures of a porous medium have been suggested, from which the fructal pore dthesion resistance has been defined. The resistance ascends obviously with the fmctal pore dimension and the conversion rutio increasing, especially in the middle-latter period of fiuid-solid reactions.
关键词:
fractal model
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Zhenya Zhang
材料科学技术（英文）
This study investigated the microstructures and mechanical properties of ZK60 alloy prepared by a simplified rapid solidification powder metallurgy (RS P/M) processing system (S-RS P/M), which consists of warm press in dry air and hot extrusion. Microstructure characterizations showed that S-RS P/M alloy consisted of magnesium matrix and oxide stringers of ~1 μm in width. TEM (transmission electron microscopy) observations illustrated nano-size magnesia particles (10{30 nm) constituted oxide stringer in detail. Due to a relatively higher volume of nano-size magnesia particle produced during S-RS P/M process, 0.2% yield strength of S-RS P/M ZK60 alloy was found to be as high as 382 MPa, which is 10% higher than that of RS P/M alloy. The improvement in mechanical properties is mainly attributed to the combination effects of Orowan mechanism and coe±cient of thermal expansion (CTE) mismatch because of the approximately same average grain size.
关键词:
Microstructure
吕会议
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王铁山
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陈建勇
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杨振
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刘盛进
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方开洪
原子核物理评论
近年来一系列实验表明,金属环境中的低能带电粒子引起的核反应截面与气体靶中的相比出现明显增大,这种现象通常被归结为电子屏蔽效应. 全面介绍了金属环境中D(d, p)T反应电子屏蔽效应的测量方法、数据分析和实验结果的规律性,并简要论述了包括德拜等离子体模型在内的各种理论模型对实验结果的解释. 通过研究,可以获得有关核物理、核天体物理和凝聚态物理的宝贵知识.
关键词:
低能核反应
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电子屏蔽效应
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德拜模型
Applied Surface Science
High corrosion resistance Cu/Ni-P coatings were electrodeposited on AZ91D magnesium alloy via suitable pretreatments, such as one-step acid pickling-activation, once zinc immersion and environment-friendly electroplated copper as the protective under-layer, which made Ni-P deposit on AZ91D Mg alloy in acid plating baths successfully. The pH value and current density for Ni-P electrodeposition were optimized to obtain high corrosion resistance. With increasing the phosphorous content of the Ni-P coatings, the deposits were found to gradually transform to amorphous structure and the corrosion resistance increased synchronously. The anticorrosion ability of AZ91D Mg alloy was greatly improved by the amorphous Ni-P deposits, which was investigated by potentiodynamic polarization curve and electrochemical impedance spectroscopy (EIS). The corrosion current density (I(corr)) of the coated Mg alloy substrate is about two orders of magnitude less than that of the uncoated. (C) 2011 Elsevier B. V. All rights reserved.
关键词:
AZ91D Mg alloy;Electrodeposition;Ni-P;Corrosion resistance;phosphorus incorporation;pure magnesium;thin-films;ni;pretreatment;deposits;behavior;copper
LIU Chunpeng XU Yousheng HUA Yixin Kunming Institute of Technology
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Kunming
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650093
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China.
材料科学技术（英文）
In applying the microwave radiation to extractive me- tallurgy,it is essential first of all to find the extent of microwave energy absorbed by various minerals experi- mentally.In this paper,more than 25 kinds of common useful minerals have been individually irradiated by a 500 W,2450 MHz microwave source in an enclosed quartz crucible to ascertain their heating temperature in a definite time.In addition,the reduction and cbloridization tests were also carried out on the titanomagnetite concentrate and pentlandite with microwave heating,respectively. These experiments indicate potential applications of util- izing microwave energy in extractive metallurgy.
关键词:
microwave radiation
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