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Preparation of ultra-thick β-SiC films using different carbon sources

materials Research Innovations 2015年 19卷 397-402页

作者： Tu, R. Zheng, D.H. Cheng, H. Han, M.X. Zhang, S. Goto, T. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology 122 Luoshi Road Wuhan430070 China Institute for Materials Research Tohoku University 2-1-1 Katahira Aoba-ku Sendai980-8577 Japan

Polycrystalline ultra-thick β-SiC films have been grown on graphite substrates via halide chemical vapour deposition method by using tetrachlorosilane (SiCl4) as silicon source, whereas methane (CH4), acetylene (C2H2), propane (C3H8) and liquid petroleum gas as carbon sources, respectively. The effects of deposition temperature (Tdep) and carbon source on the orientations, microstructures and deposition rate (Rdep) were investigated. Rdep of β-SiC films dramatically increased with increasing Tdep. In the case of C2H2, it provides a sufficient source of carbon and results in the maximum Rdep under identical Tdep compared to the other carbon sources. Conversely, CH4 decomposition in the Si-C-Cl-H system was proved to be inactive with SiCl4 in the entire range of Tdep. The orientations of the β-SiC films transform from 〈111〉 to random to 〈110〉 with increasing Tdep, and highly 〈111〉- and 〈110〉-oriented β-SiC films were fabricated at 1473 and 1773 K, respectively. © 2015 W. S. Maney & Son Ltd.

关键词： Microstructure

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Quantitative detection of molds counts in cigarette cut tobacco at early stages by an electronic nose

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Sensor Letters 2014年第1期12卷 56-63页

作者： Zhu, Chao Huang, Kaijin Yuan, Fangli Xie, Changsheng State Key Laboratory of Materials Processing and Die and Mould Technology Huazhong University of Science and Technology Wuhan 430074 China State Key Laboratory of Multiphase Complex Systems Institute of Process Engineering Chinese Academy of Science Beijing 100190 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Cigarette cut tobacco mildew will cause tremendous economic loss and human health. An improved electronic nose was developed to detect cigarette cut tobacco mildew at early stages. After storing 96 h at 30 °C and 90% RH, the molds counts in dry cigarette cut tobacco was 1.6×104 CFU/g which is much higher than the mildew threshold of 2.5×103 ˜ 3.0×103 CFU/g. Cluster analysis and loading analysis were applied to optimize the gas sensor array. For the results of canonical discriminant function analysis (DFA), both of the original sensor array and the optimized sensor array had high overall correct classification rate (96.7%). For the results of multilayer perceptron neural network (MLPNN), the correlation coefficient of the real molds counts and the prediction molds counts increased from 0.99508 to 0.99612 and the average relative error decreased from 0.42% to 0.25%. The excellent performance of the electronic nose makes it a good choice to play as a rapid and effective method to quantitatively detect molds counts in cigarette cut tobacco at early stages. Copyright © 2014 American Scientific Publishers.

关键词： Tobacco

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Effect of 2,2′-dipyridyl on the plating rate, microstructure and performance of copper-coated tungsten composite powders prepared using electroless plating

Effect of 2,2′-dipyridyl on the plating rate, microstructur...

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作者： Chen, Wenshu Luo, Guoqiang Li, Meijuan Shen, Qiang Wang, Chuanbin Zhang, Lianmeng State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Highly pure copper-coated tungsten powders were successfully prepared in fixed quantities using electroless plating, via the addition of an appropriate amount of 2,2′-dipyridyl to the plating bath. The effect of 2,2′-dipyridyl on the plating Cu rate, microstructure and performance of the coated Cu layer was studied systematically. Changing the concentration of 2,2′-dipyridyl had significant effects on the plating Cu rate, surface morphology, average grain size, purity and quantity of coated Cu. With a 2,2′-dipyridyl concentration of approximately 20-40 mg/L, the coated Cu was highly pure, with very little oxygen content (less than 0.1 wt.%). The complexation of the 2,2′-dipyridyl with cuprous ions and the absorption of the 2,2′-dipyridyl on the coated Cu surface can explain these findings. With increase in the concentration of 2,2′-dipyridyl in the plating bath, the plating Cu rate, microstructure and performance of the coated Cu layer changed steadily, indicating that the complexation and absorption of 2,2′-dipyridyl gradually approached a saturation level. High thermal performance W-Cu composite can be fabricated by using these composite powders. © 2014 Published by Elsevier B.V.

关键词： Electroless plating

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Effect of flow-field dimensions on the formability of Fe-Ni-Cr alloy as bipolar plate for PEM Fuel Cell 20

Effect of flow-field dimensions on the formability of Fe-Ni-...

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20th World Hydrogen Energy Conference, WHEC 2014

作者： Hu, Qinghui Zhang, Dongming Fu, Hao State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

The Fe-Ni-Cr alloy is a potential material as bipolar plate for proton exchange membrane fuel cell, and the stamped metal bipolar plate is a promising candidate for the traditional graphite due to the advantages of mass production, low cost and excellent performance. The flow-channel geometrical dimensions, including channel width, rib width, channel depth, draft angle and radius of the fillet, have vital influences on the formability of the alloy during the stamping process. This paper numerically investigates how the serpentine flow-field geometrical dimensions affect the formability of the alloy plate by the finite element software. The finite element model was established with different channel dimensions in this study. The results predict the proper scope of flow-field dimension for alloy used for bipolar plate, further, the stamping process of alloy plate is also optimized to obtain better performance.

关键词： Proton exchange membrane fuel cells (PEMFC)

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Theoretical Study on the C-H Activation in Decarbonylation of Acetaldehyde by NiL_2(L=SO_3CH_3) Using Density Functional Theory

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Journal of Wuhan University of technology(materials Science) 2014年第6期29卷 1170-1172页

作者：刘红飞 JIA Tiekun MIN Xinmin State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology School of Physics and Electrical Information Engineering Ningxia University Department of Materials Science and Engineering Luoyang Institute of Science and Technology

Density functional theory calculations were carried out to explore the potential energy surface（PES） associated with the gas-phase reaction of Ni L2（L=SO3CH3） with acetone. The geometries and energies of the reactants, intermediates, products and transition states of the triplet ground potential energy surfaces of [Ni, O, C2, H4] were obtained at the B3LYP/6-311＋＋G（d,p） levels in C,H,O atoms and B3LYP/ Lanl2 dz in Ni atom. It was found through our calculations that the decabonylation of acetaldehyde contains four steps including encounter complexation, C-C activation, aldehyde H-shift and nonreactive dissociation. The results revealed that C-C activation induced by Ni L2（L=SO3CH3） led to the decarbonylation of acetaldehyde.

关键词： density functional theory decarbonylation transition state energy C-C activation

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Fabrication and properties of W-Cu functionally graded material by tape-casting

Fabrication and properties of W-Cu functionally graded mater...

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5th International Symposium on advanced Ceramics, ISAC 2013 and 3rd International Symposium on advanced synthesis and processing technology for materials, ASPT 2013

作者： Luo, Guoqiang Dai, Yang Liu, Shulong Yu, Kan Shen, Qiang Zhang, Lianmeng State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

ISBN: (纸本)9783038351306

In this paper, the W-Cu functionally graded material (FGM) was prepared by using the non- Aqueous tape-casting technique combined with vacuum hot-pressing sintering. The graded composite material with high density, uniform transition and graded component was designed by 7 layers with the copper content range from 40 to 100 wt. %. Then the structures and properties of the composite were characterized. The scanning acoustic microscope (SAM) results for the W-Cu graded material showed that the interface between different layers was of high smoothness and parallel. The SEM-EDS results of cross section show that the W and Cu content changed gradually along the laminating direction after sintering. The equivalent electrical conductivity and the equivalent thermal conductivity of the W-Cu graded material were 0.3976×108 S/m and 323.5 W/(m·K), respectively, which were much higher than that of the W-40 wt. % Cu homogeneous composite. The Vickers hardness of the high tungsten content surface and the high copper surface were 163 HV and 80 HV, respectively, which were same with that of the homogeneous material. © (2014) Trans Tech Publications, Switzerland.

关键词： Functionally graded materials

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Investigation of stamping process of metallic bipolar plates in PEM fuel cell - Numerical simulation and experiments

Investigation of stamping process of metallic bipolar plates...

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作者： Hu, Qinghui Zhang, Dongming Fu, Hao Huang, Kaikai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

Flow channel in bipolar plate for PEMFC has the function of transporting the fuel and oxygen and water. Stamping process for flow channel on metallic bipolar plates is an economic and convenient method for mass production. It is extremely important to predict and prevent the tearing, wrinkling, thinning, skid mark and spring back in stamping process. In this study, finite element method is used to predict the imperfection and analyze thickness variation during the stamping process. Dynaform software is employed to predict the performance of a stamping process. Forming Limit Diagrams are used to determine the safe limit of the metallic bipolar plates. In simulation, the dimension of flow channels, punch speed, radius of punch and die and draft angle were selected as variable process parameters. Experiments were conducted to compare with the simulation results. It is demonstrated that the simulation results are in good agreement with the experimental ones for ss304 metal sheets. So simulation model could be employed as a predictive tool to provide optimal parameters for better performance of the stamping process. © 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

关键词： Skids

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The activity influence of isopropyl alcohol for flat plant Pt and Pt/C electrode

The activity influence of isopropyl alcohol for flat plant P...

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2014 Electrochemical Conference on Energy and the Environment, ECEE 2014

作者： Sun, Shuang Pan, Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan430070 China

ISBN: (纸本)9781607685555

Pt, as a precious metal, is an important component of fuel cell catalyst, however the impurities in polymer electrolyte membrane fuel cell(PEMFC) has a great influence on the electrochemical activity. This paper studies the electrochemical activity influence of isopropyl alcohol(IPA) on a flat plate Pt and Pt/C electrodes by means of cyclic voltammograms and oxygen reduction test methods, the influence of the research results show that the addition of isopropyl alcohol will not change the stripping potentials of hydrogen, but it will obviously block the absorption of proton at the Hads potentials, and the biggest oxidation current on the Pt/C electrode was larger than that on the flat plate Pt electrode;we also find that the present of IPA reduces the limit current density of the plate Pt electrode, thus further influence on the performance of the catalyst in PEMFC. © The Electrochemical Society.

关键词： Proton exchange membrane fuel cells (PEMFC)

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Novel 3DOM BiVO4/TiO2 nanocomposites for highly enhanced photocatalytic activity

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Journal of materials Chemistry A 2015年第42期3卷 21244-21256页

作者： Zalfani, Meryam Van Der Schueren, Benoit Hu, Zhi-Yi Rooke, Joanna C. Bourguiga, Ramzi Wu, Min Li, Yu Van Tendeloo, Gustaaf Su, Bao-Lian 61 rue de Bruxelles NamurB-5000 Belgium Laboratoire de Physique des Matériaux: Structure et Propriétés Groupe Physique des Composants et Dispositifs Nanométriques Faculté des Sciences de Bizerte University of Carthage Jarzouna-Bizerte7021 Tunisia University of Antwerp Groenenborgerlaan 171 AntwerpB-2020 Belgium State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Luoshi Road 122 WuhanHubei430070 China Department of Chemistry and Clare Hall College University of Cambridge Lensfield Road Cambridge United Kingdom

Novel 3DOM BiVO4/TiO2 nanocomposites with intimate contact were for the first time synthesized by a hydrothermal method in order to elucidate their visible-light-driven photocatalytic performances. BiVO4 nanoparticles and 3DOM TiO2 inverse opal were fabricated respectively. These materials were characterized by XRD, XPS, SEM, TEM, N2 adsorption-desorption and UV-vis diffuse (UV-vis) and photoluminescence spectroscopies. A references for comparison, a physical mixture of BiVO4 nanoparticles and 3DOM TiO2 inverse opal powder (0.08:1), and a BiVO4/P25 TiO2 (0.08:1) nanocomposite made also by the hydrothermal method were prepared. The photocatalytic performance of all the prepared materials was evaluated by the degradation of rhodamine B (RhB) as a model pollutant molecule under visible light irradiation. The highly ordered 3D macroporous inverse opal structure can provide more active surface areas and increased mass transfer because of its highly accessible 3D porosity. The results show that 3DOM BiVO4/TiO2 nanocomposites possess a highly prolonged lifetime and increased separation of visible light generated charges and extraordinarily high photocatalytic activity. Owing to the intimate contact between BiVO4 and large surface area 3DOM TiO2, the photogenerated high energy charges can be easily transferred from BiVO4 to the 3DOM TiO2 support. BiVO4 nanoparticles in the 3DOM TiO2 inverse opal structure act thus as a sensitizer to absorb visible light and to transfer efficiently high energy electrons to TiO2 to ensure long lifetime of the photogenerated charges and keep them well separated, owing to the direct bandgap of BiVO4 of 2.4 eV, favourably positioned band edges, very low recombination rate of electron-hole pairs and stability when coupled with photocatalysts, explaining the extraordinarily high photocatalytic performance of 3DOM BiVO4/TiO2 nanocomposites. It is found that larger the amount of BiVO4 in the nanocomposite, longer the duration of photogenerated charg

关键词： Bismuth compounds

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Perovskite Solar Cells: Solvent‐Mediated Dimension Tuning of Semiconducting Oxide Nanostructures as Efficient Charge Extraction Thin Films for Perovskite Solar Cells with Efficiency Exceeding 16% (Adv. Energy Mater. 7/2016)

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advanced Energy materials 2016年第7期6卷

作者： Wu‐Qiang Wu Fuzhi Huang Dehong Chen Yi‐Bing Cheng Rachel A. Caruso Particulate Fluids Processing Centre School of Chemistry The University of Melbourne Melbourne VIC 3010 Australia State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Materials Science and Engineering Monash University VIC 3800 Australia CSIRO Manufacturing Private Bag 10 Clayton South VIC 3169 Australia

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