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The Structure-reactivity Relationship for Metathesis Reaction between Ethylene and 2-butene of WO3 /SiO2 Catalysts Influenced by Different Calcination Temperature

The Structure-reactivity Relationship for Metathesis Reactio...

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2012 3rd International Conference on Chemistry and Chemical Engineering

作者： Somboon Chaemchuen Suphot phatanasri Francis Verpoort Nikom Sea-ma Kongkia Suriye Center of Excellent on Catalysis and Catalytic Reaction Engineering Department of Chemical EngineeringFaculty of Engineering Chulalongkorn UniversityBangkok 10330Thailand State key laboratory of advanced technology for materials synthesis and processing Wuhan University of TechnologyChina

The effect of calcination temperatures on the active species of WO 3 /SiO 2 catalysts for propylene production from metathesis of ethylene and 2-butene was studied to elucidate the structure-reactivity *** influence of calcination temperatures on catalyst physicochemical properties,relating to the active species,was summarized from an array of characterization *** has been found that the surface tetrahedral tungsten species with high metal support interaction were formed on the catalyst calcined at 550℃ as confirmed by Raman,UV-Vis and H 2-TPR spectra,respectively.

关键词： Metathesis Silica-support tungsten Structure-reactivity

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Multiscale calculations of thermoelectric properties of n-type Mg2Si1−xSnx solid solutions

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Physical Review B 2012年第20期85卷 205212-205212页

作者： X. J. Tan W. Liu H. J. Liu J. Shi X. F. Tang C. Uher Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology Wuhan University Wuhan 430072 China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Department of Physics University of Michigan Ann Arbor Michigan 48109 USA

The band structure of Mg2Si1−xSnx solid solutions with 0.250 ⩽ x ⩽ 0.875 is calculated using the first-principles pseudopotential method. It is found that the low-lying light and heavy conduction bands converge and the effective mass reaches a maximum value near x = 0.625. Using the semiclassical Boltzmann transport theory and relaxation-time approximation, we find that the system with x = 0.625 exhibits both higher Seebeck coefficient and higher electrical conductivity than other solid solutions at intermediate temperatures. By fitting first-principles total energy calculations, a modified Morse potential is constructed, which is used to predicate the lattice thermal conductivity via equilibrium molecular dynamics simulations. Due to relatively higher power factor and lower thermal conductivity, the Mg2Si0.375Sn0.625 is found to exhibit enhanced thermoelectric performance at 800 K, and additional Sb doping is considered in order to make a better comparison with experiment results.

关键词： THERMOELECTRICITY ELECTRONIC band structure PSEUDOPOTENTIAL method BOLTZMANN'S equation HEAT conduction TRANSPORT theory (Mathematics)

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Photocatalytic Degradation of Rhodamine B Dye with High Purity Anatase Nano-TiO_2 Synthesized by a Hydrothermal Method

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Journal of Wuhan University of technology(materials Science) 2011年第4期26卷 600-605页

作者：史晓亮 School of Mechanical and Electronic Engineering Wuhan University of Technology State Key Laboratory of Advanced Technology for Materials Synthesis & Processing Wuhan University of Technology

High purity anatase nano-TiO2 powders with high photocatalytic activity were prepared by a hydrothermal synthesis method. X-ray diffraction （XRD）, field emission transmission electron microscopy （FETEM）, ultraviolet-visible （UV-Vis） light absorption spectrum and photoluminescence （PL） spectrum were adopted to characterize the catalyst. Effects of temperature, time and sol concentration of hydrothermal synthesis on particle size and phases were investigated. Photocatalytic activities in the degradation of Rhodamine B Dye were studied. The experimental results indicated that photocatalytic activity of the nano-TiO2 powers was much higher than that of P25 （Degussa）.

关键词： TiO2 hydrothermal synthesis photocatalytic activity high purity anatase

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Microstructure and Mechanical Properties of TiB_2-Al_2O_3 Composites

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Journal of Wuhan University of technology(materials Science) 2011年第4期26卷 696-699页

作者：刘国玺张金咏 The Ningbo Branch of Ordnance Science Institute of China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

Effects of Al2O3 and Ni as the additives on the sinterability, microstructure and mechanical properties were systematic studied. The experimental results show that only a relative density about 96.2% of hot-pressing TiB2-30%Al2O3 can be attained due to the plate-like TiB2 particle and its random orientation and excessive Al2O3 grain growth. When sintering temperature is higher than 1 700 ℃, TiB2 grain growth can be found, which obvious improves flexural strength of TiB2 matrix but decreases toughness. It seems that mechanical properties of TiB2-Al2O3 composites are mainly depended on relative density besides grain growth. otherwise, they will be determined by relative density and TiB2 matrix strength together. Anyway, Al2O3 addition can weaken the grain boundary and thus improve the toughness of the materials. A flexural strength of 529 MPa, Vickers hardness of 24.8 GPa and indentation toughness of 4.56 MPa·m1/2 can be achieved inTiB2-30vol% Al2O3.

关键词： TiB2-Al2O3 pressureless sintering microstructure mechanical properties

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Preparation,Structure and Dielectric Properties of Tungsten Bronze Ferroelectrics in SrO-Eu_2O_3-TiO_2-Nb_2O_5 System

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Journal of Wuhan University of technology(materials Science) 2011年第2期26卷 312-315页

作者：胡长征 State Laboratory Breeding Base of Nonferrous Metals and Specific Materials Processing Guilin University of Technology Key Laboratory of Nonferrous Materials and New Processing Technology Ministry of EducationGuilin University of Technology State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

Compounds Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 with filled tetragonal tungsten bronze structure were prepared,and the dielectric characteristics and ferroelectric transition were *** ceramics displayed weak frequency dependence in room temperature dielectric constant,which decreased from 125 to 118 for Sr4Eu2Ti4Nb6O30,from 206 to 195 for Sr5EuTi3Nb7O30 in the frequency range of 10 kHz to 1 *** present ceramics showed a diffuse ferroelectric phase *** frequency independent transition temperature （Tm） indicated the above compounds had no relaxor *** diffuseness （γ） was 1.45 and 1.64 for Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 *** weak ferroelectric of the present materials are indicated from the P-E hysteresis loops,and a small 2Pr of 0.596 μC/cm2 and 0.068 μC/cm2 were observed for Sr4Eu2Ti4Nb6O30 and Sr5EuTi3Nb7O30 respectively.

关键词： tungsten bronze dielectric properties X-ray diffraction phase transition

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Photocatalytic Degradation of Rhodamine B Dye with MWCNT/TiO_2/C_(60) Composites by a Hydrothermal Method

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Journal of Wuhan University of technology(materials Science) 2011年第1期26卷 65-69页

Multi-walled carbon nanotube （MWCNT）/TiO2/C60 composite catalysts were prepared by hydrothermal method. TiO2 was deposited on the MWCNT surface. Their photocatalytic activities for degradation of Rhodamine B dye were studied. X-ray diffraction, field emission transmission electron microscopy, ultraviolet-visible light absorption spectrum and photoluminescence spectrum were carried out to characterize the composite catalysts. The results indicated that MWCNTs and C60 could greatly enhance the photocatalytic activity of TiO2.

关键词： semiconductors chemical synthesis optical properties surface properties

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Effects of novel self-inoculation method on microstructure of AM60 alloy

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China Foundry 2011年第1期8卷 121-126页

作者： Xing Bo Li Yuandong Ma Ying Hao Yuan State Key Lab. of Gansu Advanced Non-ferrous Metal Materials Lanzhou University of Technology Lanzhou 730050 China Key Lab. of Non-ferrous Metal Alloys and Processing Ministry of Education Lanzhou University of Technology Lanzhou 730050 China

A novel cast processing method,self-inoculation method (SIM),was *** process involves the addition of self-inoculant to melt,then pouring the melt to a mould through a multi-stream mixing cooling *** this paper,the process parameters were *** indicate that the melt treatment temperature,the amount of self-inoculant added,and the slope angle of the cooling channel are the key factors for SIM *** optimized parameters are that the melt treatment temperature is between 680 and 700°C;the addition of self-inoculant is between 5wt.% and 7wt.%;and the slope angle of the cooling channel is between 30° and 45°.Further analysis reveals that SIM changes the solidification microstructure of slurry by controlling the nucleation and growth of the primary phase in the melt.

关键词： AM60 alloy self-inoculation method multi-stream mixing cooling channel nucleation and growth

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Configuring pnicogen rings in skutterudites for low phonon conductivity

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Physical Review B 2012年第19期86卷 195209-195209页

作者： Hang Chi Hyoungchul Kim John C. Thomas Xianli Su Stephen Stackhouse Massoud Kaviany Anton Van der Ven Xinfeng Tang Ctirad Uher Department of Physics University of Michigan Ann Arbor Michigan 48109 USA Department of Mechanical Engineering University of Michigan Ann Arbor Michigan 48109 USA Department of Materials Science and Engineering University of Michigan Ann Arbor Michigan 48109 USA State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China School of Earth and Environment University of Leeds Leeds LS2 9JT United Kingdom

Dominant heat-carrying modes in skutterudites are associated with vibrations of the pnicogen rings. Apart from filling the structural cages with foreign species, disrupting the pnicogen ring structure by substitutional alloying should be an effective approach to reduce thermal conductivity. In this paper we explore alloying configurations of pnicogen rings (Sb rings in the case of CoSb3) that yield particularly low values of the thermal conductivity. We find that IV-VI double substitution (replacing two Sb atoms with one atom each from the column IV and column VI elements to achieve an average charge of two Sb atoms) is a very effective approach. Our ab initio calculations, in combination with a cluster expansion, have allowed us to identify stable alloy configurations on the Sb rings. Subsequent molecular and lattice dynamics simulations on low energy configurations establish the range of atomic displacement parameters and values of the thermal conductivity. Theoretical results are in good agreement with our experimental thermal conductivity values. Combining both approaches of compensated double substitution and filling of structural cages should be an effective way of improving the thermoelectric figure of merit of skutterudites.

关键词： SKUTTERUDITE PHONONS THERMAL conductivity ATOMS THERMOELECTRICITY

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Anchoring proteins to Escherichia coli cell membranes using hydrophobic anchors derived from a Bacillus subtilis integral membrane protein

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Protein expression and purification 2012年第1期85卷 60-5页

作者： Cheng Yang Hao Xie Jian-Kun Zhang Bao-Lian Su State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 PR China.

Anchored periplasmic expression (APEx) technology aims to express and localize proteins or peptides in the Escherichia coli periplasm. Some reports have suggested that transmembrane segments of integral membrane proteins can be used as membrane anchors in the APEx system. In this study, a series of hydrophobic anchors derived from the first putative transmembrane helix of a Bacillus subtilis integral membrane protein, MrpF, and its truncated forms were investigated for anchored periplasmic expression of alkaline phosphatase (PhoA) in E. coli. Anchoring efficiency of hydrophobic anchors was evaluated by monitoring the expression and activity of anchored PhoA. The length of hydrophobic anchors was found to be critical for anchoring proteins to cell membranes. This study may open new avenues for applying transmembrane segments derived from native membrane proteins as membrane anchors in the APEx system.

关键词： Membrane anchor Anchored periplasmic expression (APEx) Integral membrane protein (IMP) Transmembrane helix (TMH)

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The effect of dispersion of TiO2 nanoparticles on preparation of flexible dye-sensitized photoanodes

The effect of dispersion of TiO2 nanoparticles on preparatio...

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作者： Zhao, Xiao Chong Lin, Hong Liu, Yizhu Li, Xin Yang, Pan Chen, Huiyuan Y. Wang, Gang Li, Jian Bao State Key Laboratory of New Ceramics and Fine Processing Department of Material Science and Engineering Tsinghua University Beijing 100084 China Pen-Tung Sah Micro-Nano Technology Research Center Xiamen University Xiamen 361005 China Tianjin Institute of Power Sources Tianjin 300381 China School of Mechanical Engineering Qinghai University Xining 810016 China Key Lab. for Hainan Advantage Rsrc. and Appl. Technol. in Chem. Eng. Mat. of Ministry of Education Materials and Chemical Engineering Institute Hainan University Haikou 570228 China

Generally, nanoparticles are easy to aggregate due to their nano sizes, which influence the physical and chemical properties. In this work, a dispersion treatment of the TiO2 nanoparticles with different average sizes was employed to improve the dispersion of TiO2 nanoparticles, in order to prepare flexible photoanodes for dye-sensitized solar cells (DSCs) with novel photovoltaic properties at a low temperature. The effects of dispersion treatment on the dispersion of TiO2 nanoparticles, including the viscosities of the binder-free TiO2 paste, the morphologies and textural properties of nanoparticle-TiO2 films, and the photovoltaic properties of the flexible DSCs, were investigated. Flexible indium-tin oxide (ITO)-coated polyethylene naphthalate (PEN) substrates with sputter deposited Pt were employed as the transparent flexible counter electrodes. A short-circuit photocurrent density of 9.62 mA cm-2, an open-circuit voltage of 0.757 V, a fill factor of 0.589 and an overall light-to-energy conversion efficiency of 4.29% for the flexible DSCs under AM1.5 illumination of 100 mW-cm?2 were obtained with dispersion treatment. A 30.8% increment of the energy conversion efficiency for DSCs made by dispersion treatment was obtained compared with that made without dispersion treatment. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg.

关键词： Dye-sensitized solar cells

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