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Fabrication of nano-sized Ca(OH)_2 with excellent adsorption ability for N_2O_4

Particuology 2012年第6期10卷 737-743页

作者： Yucheng Du Qi Meng Ruiqin Hou Jing Yan Hongxing Dai Tong Zhang Key Lab of Advanced Functional Materials Ministry of Education of ChinaCollege of Materials Science and EngineeringBeijing University of Technology Beijing Special Engineering Design and Research Institute Laboratory of Catalysis Chemistry and Nanoscience Department of Chemistry and Chemical EngineeringCollege of Environmental and Energy EngineeringBeijing University of Technology

Uniform nano-sized calcium hydroxide （Ca（OH）2） monocrystal powder was synthesized from calcium oxide in a surfactant solution via a digestion method by decreasing the surface tension of the reaction system to control the growth of crystalline Ca（OH）2. The Ca（OH）2 monocrystal powder samples were characterized by means of scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, high resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）, Brunauer-Emmett-Teller （BET）, and Fourier transform-infrared spectroscopy （FT-IR）. The NOx adsorption ability of the samples was evaluated, and the influence of various types and concentrations of surfactants on powder agglomeration and then the specific surface area in the precipitation process were studied. The specific surface area of the samples was found as high as 58 m2/g and 92 m2/g and the particle size, 300-400 nm and 200-300 nm in the presence of 10 wt% PEG600 and 0.086 mL/L SDS at a reaction time of 5 h, respectively. The product has an exceptionally strong adsorption ability for NOx, which makes it a highly promising adsorbent for emission control and air purification.

关键词： Nano-sized Ca（OH）2 Surfactant Digestion method NOx collecting

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Controlled synthesis of highly active mesoporous Co3O4 polycrystals for low temperature CO oxidation

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Applied Catalysis B: Environmental 2012年 111-112卷 461-466页

作者： Feng, Yingjun Li, Liang Niu, Shufan Qu, Yan Zhang, Qian Li, Yongsheng Zhao, Wenru Li, Hua Shi, Jianlin Laboratory for Advanced Functional Materials School of Materials Science and Engineering East China University of Science and Technology Shanghai 200237 China State Key Laboratory of High Performance Ceramic and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

Polycrystalline mesoporous Co3O4 has been successfully fabricated using a simple but efficient controlled thermal decomposition approach and their catalytic activities for low temperature CO oxidation were evaluated. In such a synthesis, micrometer-sized polyhedral cobalt oxalate crystals were first prepared and used as precursor. Mesoporosity was then generated via the pyrolysis of the cobalt oxalate precursor and the resultant nano-sized Co3O4 crystallites connected together to form mesoporous structure within the original micrometer-sized particles. The as-prepared material by calcination at 300°C at a heating rate of 0.5°C/min possessed high surface area and showed extraordinarily high catalytic activity for low temperature CO oxidation, the full CO conversion can be achieved at as low as -70°C. © 2011 Elsevier B.V.

关键词： Cobalt compounds

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Prediction of stable hafnium carbides: Stoichiometries, mechanical properties, and electronic structure

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Physical Review B 2013年第21期88卷 214107-214107页

作者： Qingfeng Zeng Junhui Peng Artem R. Oganov Qiang Zhu Congwei Xie Xiaodong Zhang Dong Dong Litong Zhang Laifei Cheng Science and Technology on Thermostructural Composite Materials Laboratory School of Materials Science and Engineering Northwestern Polytechnical University Xi'an Shaanxi 710072 People's Republic of China Department of Geosciences Center for Materials by Design Institute for Advanced Computational Science State University of New York Stony Brook New York 11794-2100 USA Moscow Institute of Physics and Technology Dolgoprudny Moscow Region 141700 Russia School of Materials Science and Engineering Northwestern Polytechnical University Xi'an Shaanxi 710072 People's Republic of China Institute of Modern Physics Northwest University Xi'an Shaanxi 710069 People's Republic of China

We have performed a search for stable compounds in the hafnium-carbon (Hf-C) system at ambient pressure using a variable-composition ab initio evolutionary algorithm implemented in the uspex code. In addition to the well-known HfC, we predicted two additional thermodynamically stable compounds Hf3C2 and Hf6C5. The structure of Hf6C5 with space group C2/m contains 22 atoms in the conventional cell, and this prediction revives the earlier proposal by Gusev and Rempel [Phys. Status Solidi A 135, 15 (1993)]. The stable structure of Hf3C2 also has space group C2/m and is more energetically favorable than the Immm,P3¯m1,P2, and C2221 structures put forward by Gusev and Rempel [Phys. Status Solidi A 135, 15 (1993)]. The dynamical and mechanical stabilities of the newly predicted structures have been verified by calculations of their phonons and elastic constants. Structural vacancies are found in the ordered defective rock-salt-type HfC. Chemical bonding, band structure, and Bader charges are presented and are discussed. All three compounds are weak metals with increasing metallicity as the vacancy concentration increases. The mechanical properties of the hafnium carbides nonlinearly decrease with increasing vacancy concentration, indicating the defect tolerance of this refractory compound. It is, therefore, possible to tune the hardness, ductility, and electrical conductivity by varying the stoichiometry of the hafnium carbides.

关键词： HAFNIUM CARBIDES STOICHIOMETRY ELECTRONIC structure EVOLUTIONARY algorithms PHONONS ELASTIC constants ENERGY bands

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A novel method to fabricate tough cylindrical Ti2AlC/graphite layered composite with improved deformation capacity

A novel method to fabricate tough cylindrical Ti2AlC/graphit...

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作者： Li, Aijun Chen, Lin Zhou, Yanchun Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Graduate School of Chinese Academy of Sciences Beijing 100039 China Science and Technology on Advanced Functional Composite Laboratory Aerospace Research Institute of Materials and Processing Technology Beijing 100076 China American Ceramic Society United States

Based on the structure feature of a tree, a cylindrical Ti 2AlC/graphite layered composite has been fabricated through heat treating a graphite column and six close-matched thin wall Ti2AlC cylinders bonded with the Ti2AlC powders at 1300°C and low oxygen partial pressure. SEM examination reveals that the bond interlayers between cylinders or that between cylinder and column are not fully dense without any crack formation. During the compressive test, the strain of the Ti 2AlC/graphite layered composite is about twice higher than that of the monolithic Ti2AlC ceramic, and the compressive strength of the layered composite is 348 MPa. The layered composite show the noncatastrophic fracture behaviors due to the debonding and shelling off of the layers, which are different from the monolithic Ti2AlC ceramic. The mechanism of the improved deformation capacity and non-catastrophic failure modes are attributed to the presence of the central soft graphite column and cracks deflection by the bond interlayers.

关键词： Deformation

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Effect of thermal oxidation on the surface characteristics and corrosion behavior of a Ta-implanted Ti-50.6Ni shape memory alloy

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International Journal of Minerals,Metallurgy and Materials 2012年第12期19卷 1134-1141页

作者： Sheng-nan Wang Yan Li Ting-ting Zhao School of Materials Science and Engineering Beihang University Beijhag 100191 China Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology Beihang University Beijing 100191 China Key Laboratory of Aerospace Materials and Performance (Ministry of Education) Beihang University Beijing 100191 China

A NiTi shape memory alloy （SMA） modified by Ta ion implantation was subjected to oxidation treatment in air at 723 and 873 K. Atomic force microscopy （AFM）, Auger electron spectroscopy （AES）, and grazing incidence X-ray diffraction （GIXRD） measurements were conducted to investigate the surface characteristics, including surface topography, elemental depth profiles, and surface phase structures. The surface roughness of the Ta-implanted NiTi increases after oxidation, and the higher the oxidation temperature is, the larger the value is. The surface of the Ta-implanted NiTi oxidized at 723 K is a nanolayer mainly composed of TiO2/Ta2O5 and TiO with depressed Ni content. The Ta-implanted NiTi oxidized at 873 K is mainly covered by rutile TiO2 in several micrometers of thickness. Potentiodynamic polarization tests indicated that the corrosion resistance of the Ta-implanted NiTi was improved after thermal oxidation at 723 K, but a negative impact was found for the Ta-implanted NiTi oxidized at 873 K.

关键词： nickel alloys titanium alloys shape memory effect ion implantation oxidation corrosion resistance

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Mechanical properties of Ni_(0.83)Co_(0.15)Cu_(0.02)Fe_(1.9)O_(4-δ)+PbZr_(0.52)Ti_(0.48)O_(3)particulate composites by composite oscillator technique and the correlation with the results of magnetoelectric properties

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Journal of advanced Ceramics 2012年第4期1卷 317-326页

作者： M.Venkata RAMANA M.Penchal REDDY N.Ramamanohar REDDY B.S.MURTY K.V.SIVA KUMAR Shenhua SONG Shenzhen Key Laboratory of Advanced Materials Department of Materials Science and EngineeringShenzhen Graduate SchoolHarbin Institute of TechnologyShenzhen 518055China Department of Physics Changwon National UniversityChangwonRepublic of Korea Ceramic Composite Materials Laboratory Department of PhysicsSri Krishnadevaraya UniversityAnantapur 515003India Nanotechnology Laboratory Department of Metallurgical and Materials EngineeringIndian Institute of TechnologyChennai 600036India

The xNi_(0.83)Co_(0.15)Cu_(0.02)Fe_(1.9)O_(4-δ)+PbZr_(0.52)Ti_(0.48)O_(3)(PZT)particulate magneto ferroelectric composites with x=0,0.1,0.2,0.3,0.4,0.5 and 0.6 mole fraction were prepared by conventional ceramic double sintering *** presence of two phases(perovskite structure of ferroelectric phase and spinal structure of ferromagnetic phase)was confirmed by X-ray *** magnetoelectric(ME)property of the particulate composites was determined at room temperature as a function of intensity of magnetic *** temperature variation of the longitudinal modulus(L)and the internal friction(Q−1)of these particulate composites at 104.3 kHz was studied in the wide temperature range 30-420℃.The temperature variation of the longitudinal modulus in each composition of these particulate composites showed two abrupt *** minimum coincided with the ferroelectric-paraelectric Curie transition temperature(θE)and the other with the ferromagnetic-paramagnetic Curie transition temperature(θM).The internal friction measurement also showed two sharp peaks in each composition corresponding to those temperatures where the minima were noticed in the temperature variation of the longitudinal modulus behaviour.

关键词： X-ray diffraction magnetoelectric effect piezoelectric coefficient internal friction Curie transition temperature

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Study on leakage rate of HDPE/paraffin composite for phase change materials

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2nd International Symposium on Chemical Engineering and Material Properties, ISCEMP 2012

作者： Liu, Huan-rui Yang, Wen-bin Pu, Xin-yi Zhang, Kai State Key Laboratory Cultivation Base for Nonmetal Composite and Functional Materials Southwest University of Science and Technology Sichuan 621010 China School of Materials Science and Engineering Southwes University of Science and Technology Sichuan 621010 China Institute of System Engineering China Academy of Engineening Physics Sichuan 621010 China

ISBN: (纸本)9783037854549

Based on high density polyethylene (HDPE) as supporting and encapsulating materials, paraffin wax as energy storage materials, HDPE/paraffin composite for phase change materials was prepared in the paper. In order to low leakage rate of HDPE/paraffin composite for phase change materials, the influencing factors of leakage rate of HDPE/paraffin composite, such as temperature of mixing, time of mixing, different content of DCP, rate of cooling, were studied. The results indicated that low leakage rate of PCM could be prepared. © (2012) Trans Tech Publications, Switzerland.

关键词： Paraffins

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Locking characteristics of single mode Fabry-Perot laser diode

Locking characteristics of single mode Fabry-Perot laser dio...

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2012 International Conference on Photonics in Switching, PS 2012

作者： Wu, Jian Wei Won, Yong Hyub Nakarmi, Bikash Hoai, Tran Quoc Department of Electrical Engineering Korea Advanced Institute of Science and Technology Daejeon 305-714 Korea Republic of Department of Information and Communications Engineering Korea Advanced Institute of Science and Technology Daejeon 305-714 Korea Republic of State Key Laboratory of Millimeter Waves Nanjing 210096 China Chongqing Key Laboratory O Optoelectronic Functional Material Chongqing 400047 China

ISBN: (纸本)9782912328618

In this paper, the locking characteristics of self mode and power injection near side mode are experimentally studied based on the single mode Fabry-Perot laser diode (SMFP-LD). Results show that the system parameters such as the temperature, bias current, injection energy, and wavelength detuning will produce very important influence on the locking behaviors. The dominated mode will back and forth jump among different lasing modes for changed temperature, whose output intensity will also enhanced with the increase of bias current. In addition, while the injection wave with enough energy and judicious detuning is introduced into the laser diode, the lasing modes may be further suppressed so that the corresponding side-mode suppression ratio (SMSR) can reach up to 30dB. © 2012 SEE.

关键词： Semiconductor lasers

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Imaging: Red Emissive Biocompatible Nanoparticles from Tetraphenylethene-Decorated BODIPY Luminogens for Two-Photon Excited Fluorescence Cellular Imaging and Mouse Brain Blood Vascular Visualization (Part. Part. Syst. Charact. 4/2014)

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Particle & Particle Systems Characterization 2014年第4期31卷

作者： Zujin Zhao Bin Chen Junlong Geng Zhengfeng Chang Laura Aparicio-Ixta Han Nie Chi Ching Goh Lai Guan Ng Anjun Qin Gabriel Ramos-Ortiz Bin Liu Ben Zhong Tang College of Material Chemistry and Chemical Engineering Hangzhou Normal University Hangzhou 310036 China Bin Liu Department of Chemical and Biomolecular Engineering National University of Singapore Singapore 117576 Ben Zhong Tang Centro de Investigaciones en Óptica A. P. 1–948 37000 León Gto. México Department of Chemical and Biomolecular Engineering National University of Singapore Singapore 117576 Centro de Investigaciones en Óptica A. P. 1–948 37000 León Gto. México State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 China Singapore Immunology Network (SIgN) A*STAR (Agency for Science Technology and Research) Biopolis 138648 Singapore Zujin Zhao College of Material Chemistry and Chemical Engineering Hangzhou Normal University Hangzhou 310036 China Department of Chemistry Institute for Advanced Study State Key Laboratory of Molecular Neuroscience and Institute of Molecular Functional Materials The Hong Kong University of Science & Technology Clear Water Bay Kowloon Hong Kong China

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Morphology control of self-catalyzed germanium nanostructures with graphitic carbon shell

Morphology control of self-catalyzed germanium nanostructure...

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作者： Kim, Byung-Sung Lee, Jae-Hyun Son, Kiseok Hwang, Sung Woo Choi, Byoung Lyong Lee, Eun Kyung Whang, Dongmok Sungkyunkwan Advanced Institute of Nanotechnology School of Advanced Materials Science and Engineering Sungkyunkwan University Suwon 440-746 Korea Republic of Research Center for Time-Domain Nano-functional Devices Samsung Advanced Institute of Technology Yongin 449-712 Korea Republic of Frontier Research Laboratory Samsung Advanced Institute of Technology Yongin 449-712 Korea Republic of

The crystalline germanium nanowires (GeNWs) with a uniform graphitic carbon shell were prepared via a conventional low-pressure chemical vapor deposition method without any external catalyst. The GeNWs grown at low te... 详细信息

关键词： Nanowires

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