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Preparation and electric properties of Bi0.5Na 0.5TiO3-Bi(Al0.5Ga0.5)O3 lead-free piezoceramics

Journal of the American Ceramic Society 2013年第12期96卷 3793-3797页

作者： Wang, Qi Chen, Jun Fan, Longlong Song, Huidong Gao, Wei Rong, Yangchun Liu, Laijun Fang, Liang Xing, Xianran Department of Physical Chemistry University of Science and Technology Beijing Beijing 100083 China University of Science and Technology Beijing Beijing 100083 China Key Laboratory of New Processing Technology for Nonferrous Metals and Materials Ministry of Education Guilin University of Technology Guilin 541004 China State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China

A new lead-free BNT-based piezoelectric ceramics of (1 - x)Bi 0.5Na0.5TiO3-xBi(Al0.5Ga 0.5)O3 (x = 0, 0.02, 0.03, 0.04, and 0.05) were synthesized using a conventional ceramic fabrication method. Their structures and electrical properties were investigated. All the samples show a typical ferroelectric P(E) loops and S(E) curves at room temperature. The optimal properties are obtained at the composition of the x = 0.03. The substitution of Bi(Al0.5Ga0.5)O3 enhances piezoelectric constant and increases Curie temperature from 58 pC/N and 310°C of pure BNT to 93 pC/N and 325°C of the x = 0.03. The temperature-dependent P(E) loops and S(E) curves of 0.97BNT-0.03BAG indicate that phase transition from ferroelectric to antiferroelectric takes place over a very wide temperature region from 80°C to 180°C. The results show that the introduction of BAG improves the electrical properties of BNT. © 2013 The American Ceramic Society.

关键词： Piezoelectric ceramics

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Photocatalytic Properties of Hierarchical and Nanoporous Titania Hollow Microspheres

Photocatalytic Properties of Hierarchical and Nanoporous Tit...

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International Conference on Nanoscience & technology,China 2013(ChinaNANO 2013)

作者： Chao Zhang Jie Yang Yueli Liu Wen Chen State Key Laboratory of Advanced Technology for Materials Synthesis and Processing and School of Materials Science and Engineering Wuhan University of Technology

TiO 2 hollow structure materials had become one of the hot spots because of their low density, high specific surface areas, and good photocatalytic activity. Till now, there were lots of works focused on them, such as their extensive application in catalysis, pharmacy, sensing device, photon transmission and the basis material of DSSC. Nevertheless, the drawbacks which are out control of nanoparticles phases on the surface, raw materials wasted and visible region absorption of its structure doesn't make it get better development in the field of photocatalysis research. In the present work, sulfonated-polystyrene latex particles with the diameter varying from 500～700 nm were prepared by emulsifier-free emulsion polymerization using KPS as the anionic initiator, which was used as the template to synthesize porous titania microspheres with tunable shell thickness and void volume with the calcination at 400°*** coating reaction was processed in the mixed solvent of ethanol and acetonitrile at room temperature by hydrolyzing TBOT in the presence of ammonia. The thickness of titania shells could be controlled by varying the concentration contents of titanium tetrabutoxide (TBOT) in the ethanol/acetonitrile mixed solvents with an appropriate volume ratio (3:1). The titania shell was composed of tiny nanoparticles with a size range from 10～15 nm. The XRD analysis indicated that the calcinations temperature promoted the phase transformation of amorphous titania to an anatase TiO 2 phase, and then to rutile TiO 2 phase. To investigate the absorption properties of the TiO 2 hollow spheres, the UV–visible spectra of the TiO 2 hollow spheres were also measured, it was found that the prepared hollow sphere showed a stronger absorption in the UV-visible region than that of the P25 with a slight peak-shift towards longer wavelength, which may lead to the enhanced photocatalytic activity of tinatia hollow spheres by 53% if compared with P25 powders. In summary, hierarchical and na

关键词： TiO 2 hollow spheres, Template method, Photocatalytic property, Benzene gas

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Effect of Zn on microstructure and mechanical properties of AL-zn-Mg-Cu-Zr alloy by powder metallurgy

Effect of Zn on microstructure and mechanical properties of ...

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2013 International Conference on advanced Technologies and Solutions in Industry, ICATSI 2013

作者： Wu, Chuan Dong Li, Cheng Zhang Fang, Pan Luo, Guo Qiang Shen, Qiang State Key Lab of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Material Technology Institute of CVTC Dongfeng Motor CO.LTD Wuhan 430056 Hubei China

ISBN: (纸本)9783037857205

In this paper, full-density Al-Zn-Mg-Cu-Zr powder metallurgy(P/M) alloy is prepared by hot-press sintering in vacuum at 600°C. Experiments are conducted to evaluate the effects of Zn additive in the range of 7.2-8.4 wt.% on the microstructure and mechanical properties of Al-Zn-Mg-Cu-Zr alloys. X-ray diffraction(XRD), scanning electron microstructure(SEM) and electron probe micro-analyzer (EPMA), and mechanical properties such as tensile strength are measured. The porosity decreases gradually with increasing of Zn and it achieves 0.01% with a density of 2.95 g/cm3 at 8.4% Zn. The tensile strength reaches the maximal value of 436 MPa at 8.4% Zn. © (2013) Trans Tech Publications, Switzerland.

关键词： Aluminum alloys

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The study of artificial xenon arc lamp ageing on E-glass/vinyl ester composites

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Fuhe Cailiao Xuebao/Acta Materiae Compositae Sinica 2013年第SUPPL.期30卷 33-39页

作者： Ni, Aiqing Zhang, Lifeng Ji, Yundong Wang, Jihui State Key Laboratory of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 China

The effects of artificial xenon arc lamp ageing on E-glass/vinyl ester composite were investigated. The mechanical properties of the composite are investigated by static mechanical tests, the storage and loss moduli, Tg, the peak of tanδ by DMA, the peak location and peak intensity by FTIR for pure resin and the composite, and fracture development and the relationship between fracture density and fatigue stress level by SEM, respectively. It is found out that the most significant ageing factor is ultraviolet radiation, and that the introduction of glass fiber will accelerate the crosslink and degradation of resin.

关键词： Glass fibers

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Facile and Scalable synthesis of Graphene by Direct Transformation of Amorphous Carbide

Facile and Scalable Synthesis of Graphene by Direct Transfor...

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IUPAC 9th International Conference on Novel materials and their synthesis(NMS-IX) & 23rd International Symposium on Fine Chemistry and Functional Polymers(FCFP-XXIII)(IUPAC第九届新型材料和合成国际会议暨第23届国际精细化工和功能聚合物研讨会)

作者： Tao Peng Shichun Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China

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POROUS GRAPHENE ELECTRODES FOR PEM FUEL CELLS

POROUS GRAPHENE ELECTRODES FOR PEM FUEL CELLS

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第五届世界氢能技术大会(WHTC2013)

作者： Kun Cheng Daping He Tao Peng Haifeng Lv Mu Pan Shichun Mu State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070China

As an air-pollution-free and high efficient power generating device,proton exchange membrane fuel cell (PEMFC) has attracted a wide *** of the key components of PEMFC is catalyst,during while the support materials pla... 详细信息

关键词： Proton exchange membrane fuel cell graphene pore mass diffusion catalyst

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Electrochemical Nanowire Devices for Energy Storage

Electrochemical Nanowire Devices for Energy Storage

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International Conference on Nanoscience & technology,China 2013(ChinaNANO 2013)

作者： Liqiang Mai Chaojiang Niu Xiaocong Tian Xu Xu Qinyou An Qiulong Wei Yunlong Zhao State Key Laboratory of Advanced Technology for Materials Synthesis and Processing WUT-Harvard Joint Nano Key Laboratory Wuhan University of Technology

One-dimensional nanomaterialshave attracted significant attention for a wide range of energy-related applications due to such unique advantages as short Li-ion insertion/extraction distance, facile strain relaxation upon electrochemical cycling, enhanced electron transport, and very large surface to volume ratio. We designed the single nanowire electrode devices as a unique platform for in situ probing the direct relationship between electrical transport, structure, and electrochemical properties of the single nanowire electrode to understand intrinsic reason of capacity fading. It demonstrates that during the electrochemical reaction conductivity of the nanowire electrode decreased, which limits the cycle life of the devices. Then, the prelithiation and Langmuir-Blodgett technique have been used to improve the cycling stability of nanowire electrode. Recently, we have synthesized SVO/PANI triaxial nanowires and fabricated hierarchical MnMoO 4 /CoMoO 4 heterostructured nanowires by combining "oriented attachment" and "self-assembly". The asymmetric supercapacitors based on the hierarchical heterostructured nanowires showed a high specific capacitance and good reversibility with a cycling efficiency of 98% after 1,000 cycles. Furthermore, we fabricated Li-air battery based on hierarchical mesoporous LSCO nanowires and nonaqueous electrolytes, which exhibits ultrahigh capacity over 11000 mAh g –1 , with the improvement of one order of magnitude than LSCO nanoparticles. We also designed and synthesized novel cucumber-like MnO 2 nanoparticles-enriched V 2 O 5 /PEDOT coaxial nanowires by layer-by-layer assembly with enhanced electrochemical performance. Recently we designed a nanoscroll buffered hybrid nanostructural VO 2 (B) composed of nanobelts and nanowires with greatly improved cycle life and rate capability. It is expected that our study may extend effective and helpful methods in directions that will solve the challenge of property degradation in energy storage an

关键词： nanowire devices, lithium batteries, energy storage

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Nanosphere Cathode materials with Three-dimensional Continuous Electron Pathways for Long-life and High-rate Lithium Storage

Nanosphere Cathode Materials with Three-dimensional Continuo...

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International Conference on Nanoscience & technology,China 2013(ChinaNANO 2013)

作者： Yifan Dong Shuo Li Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing WUT-Harvard Joint Nano Key Laboratory Wuhan University of Technology

Lithium-ion batteries （LIBs） are receiving considerable attention as storage devices in the renewable and sustainable energy developments. However, facile fabrication of long-life and high-rate cathode materials for LIBs is required to facilitate practical application. Among the candidate materials for high power LIBs, sodium super ionic conductor （NASICON） structured polyanion-based orthophosphate Li 3 V 2 （PO 4 ） 3 exhibits high energy and power density, and has been regarded as a prospective alternative cathode material in high power facilities such as electric vehicles, hybrid electric vehicles, and other power-supply equipment. Nevertheless, Li 3 V 2 （PO 4 ） 3 still faces some challenges such as low electronic conductivity and capacity fading during cycling. Here we propose a rationally controllable synthesis of highly crystalline Li 3 V 2 （PO 4 ） 3 nanospheres with a uniform carbon coating layer to restrain structure degradation during cycling. Additionally, acetylene black was used as the reducing agent and the template for particle growth, as well as a three-dimensional conductive and flexible network to provide a continuous electron pathway in the electrode. The uniform carbon layer and the conductive carbon network have a synergetic effect to enhance not only the cycling stability but also rate performance of Li 3 V 2 （PO 4 ） 3 in the application for LIBs. The as-prepared cathode material has a discharge capacity of 142 mA h g -1 at 1 C rate, approaching its theoretical value （150 mA h g -1 ）, and can even be cycled at a rate as high as 30 C without capacity fading. After 1000 cycles at a rate of 5 C, the as-prepared material has capacity retention of up to 83%, and can also tolerate 5000 cycles with a considerable capacity, demonstrating excellent cycling stability. Our work shows that this material has great potential for high-energy and high-power energy storage applications, and this rational method can be applied to synthesizing high-performance catho

关键词： lithium batteries energy storage long-life high-rate

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Nanoscroll Buffered Hybrid Nanostructure for Long-Life and High-Rate Lithium Storage

Nanoscroll Buffered Hybrid Nanostructure for Long-Life and H...

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International Conference on Nanoscience & technology,China 2013(ChinaNANO 2013)

作者： Qiulong Wei Qinyou An Liqiang Mai State Key Laboratory of Advanced Technology for Materials Synthesis and Processing WUT-Harvard Joint Nano Key Laboratory Wuhan University of Technology

Rechargeable lithium batteries have been widely used for consumer electronics and are desirable for the development of hybrid electric vehicles and electric vehicles, due to their high energy density and good environment compatibility. The enhanced electrochemical performance of electrodes depends on not only the material intrinsic characteristics, but also the designed morphologies. One-dimensional （1D） nanostructures can offer large surface area and efficient electron transport pathway to achieving high capacity. As a functional nanostructure, nanoscroll with open ends/edges could provide easy radial expansion by interlayer sliding to buffer the swelling during lithiation/delithiation. Herein, we report a nanoscroll buffered hybrid nanostructural VO 2 （B）（HNS） composed of nanobelts and nanowires with greatly improved cycle life and rate capability. It is found that this unique HNS with buffered section provides facile strain relaxation to accommodate the volume variations during lithiation/delithiation, which greatly enhance the structural stability and cyclability. Further, the interior of nanoscrolls and the interconnected voids between the hybrid nanostructures could shorten the lithium ion diffusion pathway for fast charge/discharge. As a result, the HNS cathode exhibits long-life performance with capacity retention over 82% after 1,000 cycles at C （1,000 mA g -1 ）, and high rate up to ～20 C （2,000 mA g -1 ）. This unique HNS can be applied to the next-generation high-performance batteries for portable electronics and large-scale energy storage devices. Constructing the nanoscroll buffered hybrid nanostructure described in this paper is a facile and effective method to enhance the electrochemical performance of other electrode materials.

关键词： lithium batteries, nanoscrolls, nanowires, hybrid nanostructure, nano energy

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One-step synthesis of Highly Monodisperced and Thermally Stable PtPd Bimetallic Nanoparticles in Mesocellular Silica Foam

One-step Synthesis of Highly Monodisperced and Thermally Sta...

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International Conference on Nanoscience & technology,China 2013(ChinaNANO 2013)

作者： Jie Ying Nan Jiang Wei Gen Li Lu Shengchun He Jie He Xiaoyu Yang Baolian Su State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Laboratory of Inorganic Materials Chemistry University of Namur (FUNDP)

The preparation and stabilization of metallic nanoparticles are of great importance in the field of nano-catalysis. The developments in supermolecular self-assembled porous materials enabled catalytic metal nanoparticles to be hosted inside the pores of such porous materials for enhancing the stability of these metallic nanoparticles, which is the drawback for bare metallic nanoparticles because of their deformation or aggregation. Herein, we report the design of a high-surface-area model catalytic system that consists of highly uniform PtPd bimetallic nanocrystals inside of mesocellular foam (PtPd@MCF) via one-step simple and easy impregnation route. The inorganic silica meso-channels play dual important roles in mass transfer of bimetallic nanoparticle synthesis and catalysis reation. This study represents a strategy in catalyst design that utilizes nanoscience to fabricate active catalyst sites, which are grown inside a support to produce a model heterogeneous catalyst. The results suggest that the high thermal stability of these composites are excellent nanocatalytic systems for high-temperature catalytic reations. The synthetic approach described here in facile and general for the design of practical catalysts and nanoreactors, which combined functionalities in all of the compositions. The design concept can also be extended to other metal/metal oxide compositions and porous materials for the design of various function composites.

关键词： PtPd bimetal Mesocellular silica foam thermal stability catalysis

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