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Mechanical properties of WC–Co coatings with different decarburization levels

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Rare Metals 2014年第3期33卷 313-317页

作者： Xu Wu Zhi-Meng Guo Hai-Bin Wang xiao-yan song School of Materials Science and Engineering University of Science and Technology Bejing College of Materials Science and Engineering Beijing University of Technology

In this study, two kinds of WC-Co coatings with different decarburization levels were deposited by high-velocity oxy-fuel（HVOF） spraying using the ultrafine WC-Co composite powder and commercial micronsized powder, respectively. The hardness and elastic modulus were measured on the top surface and cross sections of the prepared coatings by the nanoindentation method. The results show that the ultrafine-structured coating has much higher density and inhibited decarburization than the conventional coating, which thus results in higher hardness and elastic modulus values than the micronsized coating. The wear resistance of thermal-sprayed cermet coatings greatly depends on the cross-sectional hardness and elastic modulus which reflects the bond strength between splats to some extent. Based on the analysis, a better understanding of the microstructure and properties in cermet coating materials was obtained.

关键词： Composite powder Cermet coating Decarburization Nanoindentation Wear resistance

Microstructure and performance of WC-Co-Cr coating with ultrafine/nanocrystalline structures

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Rare Metals 2018年第11期37卷 968-975页

作者： Xue-Zheng Wang Hai-Bin Wang Xue-Mei Liu Chao Hou xiao-yan song College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials Education Ministry of ChinaBeijing University of Technology

The WC-lOCo-4Cr composite powder was synthesized firstly. Then the composite powder was agglomerated to prepare thermal spraying feedstock. The ultrafine/nanostructured WC-lOCo-4Cr coating was prepared by high velocity oxygen fuel thermal spraying. The phase constitution, elemental distribution and microstructure of the coating were characterized by X-ray diffraction and transmission electron microscopy, respectively. The wear resistance and corrosion resistance of the prepared composite coating were tested. The results show that the main phases of the coating include WC, binding phase with partial amorphous structure, with a little WC and Co(Cr)coexisting. The distributions of Co and Cr elements from the phase boundary to the eutectic area then to Co zone were analyzed quantitatively. The mechanisms for the formation of the microstructure and effects of Cr on the performance of the composite coating are proposed.

关键词： In situ synthesis High velocity oxygen fuel Ultrafine/nanostructure Composite coating Phase constitution

Thermodynamic simulation of the effect of slag chemistry on the corrosion behavior of alumina–chromia refractory

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International Journal of Minerals,Metallurgy and Materials 2016年第12期23卷 1458-1465页

作者： Shi-xian Zhao Bin-li Cai Hong-gang Sun Gang Wang Hong-xia Li xiao-yan song State Key Laboratory of Advanced Refractories Sinosteel Luoyang Institute of Refractories Research Co. Ltd. School of Materials Science and Engineering Beijing University of Technology

The corrosion behavior of alumina-chromia refractory against two kinds of industrial slags （coal slag and iron smelting slag） at 1550℃ was investigated via thermodynamic simulations. In the proposed simulation model, the initial slag first attacks the matrix and surface aggregates and subsequently attacks the inner aggregates. The simulation results indicate that the slag chemistry strongly affects the phase formation and corrosion behavior of the refractory brick. Greater amounts of alumina were dissolved and spinel solid phases formed when the brick interacted with iron smelting slag. These phenomena, as well as the calculated lower viscosity, may lead to much deeper penetration than that exhibited by coal slag and to more severe corrosion compared to that induced by coal slag. The thermodynamic calculations well match the experimental observations, demonstrating the efficiency of the proposed simulation model for evaluating the corrosion behavior of alumina-chromia refractory.

关键词： thermodynamic analysis simulation corrosion spinel alumina chromia refractories

Crystal structures and magnetic performance of nanocrystalline Sm-Co compounds

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Frontiers of Materials Science 2012年第3期6卷 207-215页

作者： xiao-yan song Zhe-Xu ZHANG Nian-Duan LU Hai-Ning LIANG Ding-Peng LI Xiang-Quan yan Jiu-Xing ZHANG College of Materials Science and Engineering Key Laboratory of Advanced Functional Materials(Ministry of Education)Beijing University of TechnologyBeijing 100124China

A variety of intermetallic compounds in the binary Sm Co system were reviewed, and the contents were focused on the crystal structures, magnetic properties and the nanoscale effects. The representative nanocrystalline Sm-Co compounds were introduced in details, the diagrams for their lattice structures and the atomic sites and occupancies were provided. Moreover, the magnetic properties of the nanocrystalline Sm-Co compounds were compared with those of the conventional polycrystalline counterparts. It showed that the nanocrystalline Sm Co compounds exhibit special phase stability and remarkably enhanced magnetic performance, which are promising candidates for the matrix phases to develop permanent magnets, particularly the advanced high-temperature magnetic materials.

关键词： Sm-Co compounds nanoscale crystal structure magnetic performance

Using CropSyst to Simulate Spring Wheat Growth in Black Soil Zone of Northeast China

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Pedosphere 2006年第3期16卷 354-361页

作者： WANG Zong-Ming, ZHANG Bai LI xiao-yan song Kai-Shan LIU Dian-Wei ZHANG Shu-Qing Northeast Institute of Geography and Agricultural Ecology Chinese Academy of Sciences Changchun 130012 （China）

Available water and fertilizer have been the main limiting factors for yields of spring wheat, which occupies a large area of the black soil zone in northeast China; thus, the need to set up appropriate models for scenario analysis of cropping system models has been increasing. The capability of CropSyst, a cropping system simulation model, to simulate spring wheat growth of a widely grown spring cultivar, 'Longmai 19', in the black soil zone in northeast China under different water and nitrogen regimes was evaluated. Field data collected from a rotation experiment of three growing seasons (1992-1994) were used to calibrate and validate the model. The model was run for 3 years by providing initial conditions at the beginning of the rotation without reinitializing the model in later years in the rotation sequence. Crop input parameters were set based on measured data or taken from CropSyst manual. A few cultivar-specific parameters were adjusted within a reasonable range of fluctuation. The results demonstrated the robustness of CropSyst for simulating evapotranspiration, aboveground biomass, and grain yield of 'Longmai 19' spring wheat with the root mean square errors being 7%, 13% and 13% of the observed means for evapotranspiration (ET), grain yield and aboveground biomass, respectively. Although CropSyst was able to simulate spring production reasonably well, further evaluation and improvement of the model with a more detailed field database was desirable for agricultural systems in northeast China.

关键词： black soil zone of northeast China cropping system simulation model validation spring wheat

Ab initio investigation of excited state dual hydrogen bonding interactions and proton transfer mechanism for novel oxazoline compound

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Chinese Physics B 2019年第10期28卷 309-314页

作者： Yu-Sheng Wang Min Jia Qiao-Li Zhang xiao-yan song Da-Peng yang College of Physics and Electronics North China University of Water Resources and Electric PowerZhengzhou 450046China State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Owing to the importance of excited state dynamical relaxation, the excited state intramolecular proton transfer(ESIPT) mechanism for a novel compound containing dual hydrogen bond(abbreviated as "1-enol") is studied in this *** density functional theory(DFT) and time-dependent density functional theory(TDDFT) method, the experimental electronic spectra can be reproduced for 1-enol compound. We first verify the formation of dual intramolecular hydrogen bonds, and then confirm that the dual hydrogen bond should be strengthened in the first excited state. The photo-excitation process is analyzed by using frontier molecular orbital(HOMO and LUMO) for 1-enol compound. The obvious intramolecular charge transfer(ICT) provides the driving force to effectively facilitate the ESIPT process in the S1 state. Exploration of the constructed S0-state and S1-state potential energy surface(PES) reveals that only the excited state intramolecular single proton transfer occurs for 1-enol system, which makes up for the deficiencies in previous experiment.

关键词： excited state intramolecular proton transfer potential energy surface intramolecular charge transfer infrared vibrational spectra

Elastic modulus of nanocrystalline cemented carbide

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Transactions of Nonferrous Metals Society of China 2018年第5期28卷 966-973页

作者： Xue-mei LIU Hai-bin WANG xiao-yan song Riccardo MOSCATELLI College of Materials Science and Engineering Beijing University of Technology Beijing 100124 China Engineering Department University of Rome ＂ROMA TRE＂ 00146 Rome Italy

The purposes of this work were to obtain the accurate elastic modulus of the nanocrystalline WC-Co cemented carbides, and to propose the mechanism for the difference of elastic modulus between the nanocrystalline and conventional polycrystalline cemented carbides. The nanocrystalline cemented carbide was prepared by spark plasma sintering（SPS） technique. The conventional polycrystalline cemented carbides were prepared by SPS and sinter-HIP techniques as references, respectively. The sintered cemented carbides were characterized by X-ray diffractometry, scanning electron microscopy and the transmission electron microscopy with precession electron diffraction technology. The elastic modulus was obtained by averaging the values measured with the continuous stiffness measurement method of the nanoindentation technology. The results show that the nanocrystalline cemented carbide has a relatively low modulus, which could be attributed to the more interface area and higher fraction ratio of the hcp cobalt phase caused by the rapid heating and cooling process during SPS.

关键词： nanocrystalline cemented carbide elastic modulus nanoindentation spark plasma sintering cobalt phase

An initial study on liner-like Z-pinch loads with a novel configuration on Qiangguang-I facility

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Nuclear Science and Techniques 2021年第9期32卷 116-125页

作者： Zhan-Chang Huang Shi-Jian Meng Ze-Ping Xu Jian-Lun yang Fu-Yuan Wu Fa-Xin Chen xiao-song yan Rong-Kun Xu Zheng-Hong Li Hong-Wei Xie yan-Yun Chu Fan Ye Jia-Min Ning Jian Lu Shu-Qing Jiang Rui-Hua yang Institute of Nuclear Physics and Chemistry Mianyang 621900China E.T.S.I.Aeronauticos y del Espacio Universidad Politecnica de Madrid28040 MadridSpain

A series of liner-like Z-pinch loads with a novel configuration have been investigated experimentally for the first time on Qiangguang-I facility in *** metallic layer is sputtered on the inner surface of the cylindrical SiO 2 substrate *** the preliminary experiment,the electric current flowed through the metallic load during the ***,the currents also flowed through the outer surface of the SiO 2 substrate during the main *** the dielectric length had been increased in the formal experiment,most of the current flowed through the metallic load until radial radiation peak was measured by radiation *** the line mass of the metallic load increases,the peak time of radial radiation also *** ultravi-olet frames indicate that the radiations are nearly azi-muthally uniform at first,but the uniformity becomes worse after radial radiation *** clearly separated boundary between the metal plasmas and the substrate has not been observed in the *** results are discussed and compared with simulation using the one-dimension radiation hydrodynamics code MULTI-IFE.

关键词： Z-pinch Liner-like UV frame Qiangguang-I

Expression and location of Smad2,4 mRNAs during and after liver fibrogenesis of rats

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World Journal of Gastroenterology 2006年第10期12卷 1577-1582页

作者： yang Liu Li-Feng Wang Hai-Feng Zou xiao-yan song Hua-Feng Xu Ping Lin Hai-Hong Zheng xiao-Guang Yu Department of-Biochemistry and Molecular Biology Harbin Medical University Harbin 150086 Heilongjiang Province China Department of Pathology of the First Clinical College Harbin Medical University Harbin 150001 Heilongjiang Province China Department of Experimental Animal of the Second Clinical College Harbin Medical University Harbin 150086 Heilongjiang Province China Master degree student of Department of Pathology of Harbin Medical University Harbin 150086Heilongjiang Province China

AIM： To investigate the location alteration of Smad2 and Smad4 mRNAs in the liver during and after fibrogenesis in rats. METHODS： Eighty male Wistar rats weighing approximately 200 g each were used. The rat models of experimental hepatic fibrosis were established by injection with carbon tetrachloride （CCh）, normal rats and rats were injected with olive oil and served as control groups. In situ hybridization（ISH） was used to detect the Smad2 and Smad4 mRNA in liver. RESULTS： In situ hybridization showed Smad2 and Smad4 mRNA expressions in the cytoplasm of hepatic stellate cells （HSC）, fibroblasts and myofibroblasts around the central vein and hepatic sinus during and after fibrogenesis. Expression of Smad2, 4 mRNA was higher than that in normal and control rats. CONCLUSION： In the process of and after hepatic fibrosis formation, HSC, fibroblasts and myofibroblasts are the major cells that express Smad2 and Smad4. The more serious the hepatic fibrosis is in the injured liver, the higher the level of Smad2 and Smad4 gene expression is during and after fibrogenesis respectively.

关键词： Smad2, Smad4 mRNA, Liver fibrogenesis