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Influence of ZrC on the microstructure of its surrounding resin-based carbon at high temperature

Carbon 2016年 110卷 523-523页

作者： Zhong-wei Zhang Min Mei Liang Li Ce-wen Nan Jun-shan Wang Zheng-hui Xu State Key Laboratory of New Ceramics & Fine Processing Department of Materials Science and Engineering Tsinghua University Beijing 100084 China Science and Technology on Advanced Functional Composites Laboratory Aerospace Research Institute of Materials and Processing Technology Beijing 100076 China China Academy of Launch Vehicle Technology Beijing 100076 China

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Oxidation Behaviors of C-ZrB_2-SiC Composite at 2100℃ in Air and O_2

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Journal of materials Science & technology 2014年第12期30卷 1223-1229页

作者： Zhongwei Zhang Cewen Nan Jingjun Xu Zenghua Gao Meishuan Li Junshan Wang State Key Laboratory of New Ceramics & Fine Processing Department of Materials Science and Engineering Tsinghua University Science and Technology on Advanced Functional Composites Laboratory Aerospace Research Institute of Materials and Processing Technology Institute of Metal Research Chinese Academy of Sciences

The oxidation behaviors of graphite and ZrB2-SiC modified graphite composite were investigated at 2100℃ in1X105 Pa air and 0.2X105 Pa O2. The oxidation tests were conducted in an induction heating furnace. The oxidation of these two materials followed the linear rate law. The determined radius loss rates of graphite and C-ZrB2-Si C at 2100℃ were 2.18X10-2and 1.05X10-2%/s in 1X105 Pa air, and 3.23X10 2 and 2.21X10 2%/s in 0.2X105 Pa O2, respectively. The incorporation of ZrB2 and SiC decreased remarkably the oxidation rate of graphite because the oxide scale formed on the sample surface during oxidation helps in reducing the exposed surface area of the underneath substrate. In two different atmospheres with the same oxygen partial pressure, both graphite and ZrB2-SiC experienced more severe oxidation at 2100℃ in0.2X105 Pa O2than in 1X105 Pa air. The oxidation rate-controlling step for graphite and ZrB2-SiC was proposed to be the inward diffusion of oxygen through the boundary layer and through the pores in the oxide scale, respectively. A model based on diffusion theory was established to discuss the effect of the total gas pressure on their oxidation behaviors.

关键词： Graphite-based composite Ceramic particles Ultra-high temperature oxidation Oxide scale Oxidation mechanism

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Preparation and electrical properties of the new lead-free (1 - X )Bi0.5Na0.5TiO3-xBa(Ni1/3Nb2/3)O3 piezoelectric ceramics

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Journal of the Ceramic Society of Japan 2015年第1443期123卷 1038-1042页

作者： Pan, Zhao An, Mingjie Chen, Jun Fan, Longlong Liu, Laijun Fang, Liang Xing, Xianran Department of Physical Chemistry University of Science and Technology Beijing Beijing100083 China State Key Laboratory for Advanced Metallurgy University of Science and Technology Beijing Beijing100083 China Key Laboratory of New Processing Technology for Nonferrous Metals and Materials Ministry of Education Guilin University of Technology Guilin541004 China

A new lead-free piezoelectric ceramics of (1 - x)Bi0.5Na0.5TiO3-xBa(Ni1/3Nb2/3)O3 (BNTBNN) (x = 0.00.07) have been prepared by a conventional solid reaction method. Their structures and electric properties have been investigated systematically. A pure perovskite phase can be formed in x ≤ 0.06. By the introduction of Ba(Ni1/3Nb2/3)O3, the ceramics exhibit a lower coercive field EC. Composition for x = 0.02 shows optimal piezoelectric properties, with the piezoelectric coefficient d33 = 121 pC/N. Temperature dependent P(E) loops and S(E) curves of 0.98BNT0.02BNN indicate that the phase transition from the ferroelectric to antiferroelectric takes place over a very wide temperature range from 75 to 150°C. © 2015 The Ceramic Society of Japan. All rights reserved.

关键词： Perovskite

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First principles study of oxidation behavior of irradiated graphite

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Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with materials and Atoms 2015年 352卷 160-166页

作者： Juan Liu Limin Dong Chen Wang Tongxiang Liang Wensheng Lai Beijing Key Lab of Fine Ceramics Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China State Key Lab of New Ceramic and Fine Processing Tsinghua University Beijing 100084 China Advanced Material Laboratory School of Materials Science & Engineering Tsinghua University Beijing 100084 China

The relationship between nuclear graphite microstructure and its oxidation resistance underlines the importance of comprehensive oxidation characterization studies of the new grades of nuclear graphite. Periodic DFT calculations are performed to model oxidation behavior of irradiated graphite. O 2 molecules adsorbed on perfect and defective graphite surfaces are calculated. The adsorptive energy of O 2 on defective graphite adsorption site with one carbon atom missing is approximately 10 times as strong as that on a defect-free perfect graphite surface. Monovacancy and divacancy on graphite surface can easily chemisorb O 2 molecule compared to perfect surface. Two oxidation processes including CO and CO 2 formation steps are analyzed. For symmetric monovacancy defect, three dangling C atoms are unsaturated and exhibit high adsorption ability, as well as reconstructed monovacancy and divacancy defects. These vacancy defects in irradiated graphite decrease oxidation resistance of nuclear graphite.

关键词： Nuclear graphite Irradiation Oxidation First-principles calculation

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Thermal annealing of C ion irradiation defects in nuclear graphite studied by positron annihilation

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Journal of Physics: Conference Series 2016年第1期674卷

作者： C Q Shi H Schut Z C Li State Key Lab of New Ceramic and Fine Processing School of Materials Science & Engineering Tsinghua University Beijing China Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 2629 JB Delft the Netherlands Key Laboratory of Advanced Materials (MOE) School of Materials Science & Engineering Tsinghua University Beijing China To whom any correspondence should be addressed.

In order to investigate the thermal behaviour of radiation induced point defects in nuclear graphite, ETU10 graphite was implanted with 350 keV C+ ion to doses of 1015 and 1016 cm-2. The point defects introduced by the implantation were characterized by Positron Annihilation Doppler Broadening (PADB) and their thermal behaviour was studied during 'in situ' annealing at Delft Variable Energy Positron beam (VEP). The annealing was performed for 5 minutes at temperatures ranging from 300 K (as implanted) to 1500 K in steps of 100 K. For both doses, an annealing stage at around 450 K is observed followed by a second stage around 700 K. For the high dose implantation vacancy complexes are found which are stable up to a temperature around 1400K.

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The 5th International Conference on Biomedical Engineering and Biotechnology (ICBEB 2016) Abstracts

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BMC MEDICAL IMAGING 2016年第SUPPL 1期16卷 65-65页

作者： [Anonymous] Department of MRI Shandong Medical Imaging Research Institute Affiliated to Shandong University Jinan Shandong 250021 People’s Republic of China Department of Interventional Radiology Shandong Provincial Hospital Affiliated to Shandong University Jinan Shandong 250021 People’s Republic of China College of Information Science and Technology Engr. Research Center of Digitized Textile & Fashion Tech. for Ministry of Education Donghua University Shanghai 201620 China Intelligent multimedia information processing Lab College of Software Northeastern University Shenyang Liaoning Province 110004 China Institute of Biomedical and Health Engineering Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 China School of Computer Science and Technology Nanjing Normal University Nanjing China Department of Electrical Engineering The City College of New York CUNY New York USA Jiangsu Key Laboratory of 3D Printing Equipment and Manufacturing Nanjing China School of Electronic Science and Engineering Nanjing University Nanjing Jiangsu 210046 China College of Engineering Nanyang Technological University Singapore 639798 Singapore School of Electronic Information Shanghai Dianji University Shanghai China School of Natural Sciences and Mathematics Shepherd University Shepherdstown WV 25443 USA Davis College of Agriculture Natural Resources and Design West Virginia University Morgantown WV 26505 USA State Key Laboratory of Millimeter Waves Southeast University Nanjing 210096 China Center of Medical Physics and Technology Hefei Institutes of Physical Science Chinese Academy of Sciences Hefei China College of Agricultural and Life Sciences University of Florida Gainesville FL 32611 USA Courant Institute of Mathematical Sciences New York University New York NY 10012 USA Translational Imaging Division & MRI Unit Columbia University and New York State Psychiatric Institute New York NY 10032 USA Guangxi Key Laboratory of Manufacturing System & Adv

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Compatibility of polyvinylidene difluorid/polyurethane and preparation of composite tubular membrane

Compatibility of polyvinylidene difluorid/polyurethane and p...

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2014 International Conference on materials Science and Engineering technology, MSET 2014

作者： Zuo, Dan-Ying Li, Hong-Jun Yi, Chang-Hai Gan, Hou-Lei State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile University Hubei 430073 China Department of Industrial Engineering Wuhan Textile University Hubei 430073 China

ISBN: (纸本)9783038351023

The compatibility of polyvinylidene difluorid (PVDF) and polyurethane (PU), the thermodynamics of the PVDF/PU/DMF (N-N-Dimethylformamide) membrane-forming systems were studied, and the composite tubular membranes of PVDF/PU-PET knitted fabric tube were prepared by the immersion precipitation phase inversion method. The results showed that the PVDF/PU system was partly compatible by the measurements of the solubility parameter theory, the mixing enthalpy, the viscosity. With PU content increasing, the gelation values increased and the instantaneous liquid-liquid phase separation was preferred to occur. The water flux of the composite tubular membranes were enhanced from 1264.81 to 2165.35 L/m2.h with PU content increasing from 10wt% to 40wt%, which resulted from the an increment of the membrane porosity and the improvement of the hydrophilicity. © (2014) Trans Tech Publications, Switzerland.

关键词： Phase separation

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Fuel Cells: 3D Quantification of Low-Coordinate Surface Atom Density: Bridging Catalytic Activity to Concave Facets of Nanocatalysts in Fuel Cells (Small 46/2016)

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Small 2016年第46期12卷

作者： Ye Xia Xiaoyan Zhong Xiaoxing Ke Gui-Rong Zhang Zhiying Cheng Bo-Qing Xu National Center for Electron Microscopy in Beijing Laboratory of Advanced Materials (MOE) the State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China EMAT (Electron Microscopy for Materials Science) University of Antwerp Groenenborgerlaan 171 B-2020 Antwerp Belgium Institute of Microstructure and Property of Advanced Materials Beijing University of Technology Beijing 100124 China Innovative Catalysis Program Key Lab of Organic Optoelectronics & Molecular Engineering Department of Chemistry Tsinghua University Beijing 100084 China

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Three-dimensional porous graphene sponges assembled with the combination of surfactant and freeze-drying

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Nano Research 2014年第10期7卷 1477-1487页

作者： Rujing Zhang Yachang Cao Peixu Li Xiaobei Zang Pengzhan Sun Kunlin wang Minlin Zhong Jinquan Wei Dehai Wu Feiyu Kang Hongwei Zhu School of Materials Science and Engineering State Key Laboratory of New Ceramics and Fine Processing Key Laboratory of Materials Processing Technology of MOE Tsinghua University Beijing 100084 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China Advanced Materials Institute Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China Center for Nano and Micro Mechanics Tsinghua University Beijing 100084 China

With the combination of surfactant and freeze-drying, we have developed two kinds of graphene spongy structures. On the one hand, using foams of soap bubbles as templates, three-dimensional porous graphene sponges with rich hierarchical pores have been synthesized. Pores of the material contain three levels of length scales, including millimeter, micrometer and nanometer. The structure can be tuned by changing the freezing media, adjusting the stirring rate or adding functional additives. On the other hand, by direct freeze-drying of a graphene oxide/surfactant suspension, a porous framework with directionally aligned pores is prepared. The surfactant gives a better dispersion of graphene oxide sheets, resulting in a high specific surface area. Both of the obtained materials exhibit excellent absorption capacity and good compression performance, providing a broad range of possible applications, such as absorbents, storage media, and carriers.

关键词： graphene sponge hierarchical freezing media porous foams

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Positron annihilation study of Fe-ion irradiated reactor pressure vessel model alloys

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Journal of Physics: Conference Series 2016年第1期674卷

作者： L Chen Z C Li H Schut N Sekimura State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and Engineering Tsinghua University Beijing 100084 China Department of Nuclear Engineering and Management The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Key Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering Tsinghua University Beijing 100084 China To whom any correspondence should be addressed. Department of Radiation Science and Technology Delft University of Technology Mekelweg 15 2629 JB Delft the Netherlands

The degradation of reactor pressure vessel steels under irradiation, which results from the hardening and embrittlement caused by a high number density of nanometer scale damage, is of increasingly crucial concern for safe nuclear power plant operation and possible reactor lifetime prolongation. In this paper, the radiation damage in model alloys with increasing chemical complexity (Fe, Fe-Cu, Fe-Cu-Si, Fe-Cu-Ni and Fe-Cu-Ni-Mn) has been studied by Positron Annihilation Doppler Broadening spectroscopy after 1.5 MeV Fe-ion implantation at room temperature or high temperature (290 oC). It is found that the room temperature irradiation generally leads to the formation of vacancy-type defects in the Fe matrix. The high temperature irradiation exhibits an additional annealing effect for the radiation damage. Besides the Cu-rich clusters observed by the positron probe, the results show formation of vacancy-Mn complexes for implantation at low temperatures.

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