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Magnetron sputtering synthesis of large area well-ordered boron nanowire arrays

science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 403-415页

作者： CAO Limin1,2. ZHANG Ze2.& WANG Wenkui1,2.1. Key Laboratory of Metastable materials science and {2. and College of materials science and Engineering, Yanshan university, Qinhuangdao 066004, china 2. Institute of Physics, Chinese Academy of sciences, Beijing 100080, china Key Laboratory of Metastable materials science and {2. and College of materials science and Engineering Yanshan University Qinhuangdao China Institute of Physics Chinese Academy of Sciences Beijing China

One-dimensionally nanostructured materials, such as nanowires and nanotubes, are the smallest dimensional structures for efficient transport of electrons and excitons, and are therefore critical building blocks for nanoscale electronic and mechanical devices. In this paper, boron nanowires with uniform diameters from 2. to 80 nm were synthesized by radio-frequency magnetron sputtering of pure boron powder and B2.3 powder mixtures in argon atmosphere. The boron nanowires produced stand vertically on the substrate surface to form well-ordered arrays over large areas with self- organized arrangements without involvement of any template and patterned catalyst. The high-density boron nanowires are parallel to each other and well distributed, forming highly ordered and uniform arrays. A more interesting and unique feature of the boron nanowires is that most of their tips are flat rather than hemispherical in morphologies. Detailed studies on its structure and composition indicate that boron nanowires are amorphous. Boron nanowire appears as a new member in the family of one-dimensional nanostructures. Considering the unique properties of boron-rich solids and other nanostructures, it is reasonable to expect that the boron nanowires will display some exceptional and interesting properties. A vapor-cluster-solid (VCS) mechanism was proposed to explain the growth of boron nanowires based on our experimental observations.

关键词： boron nanowires, magnetron sputtering, arrays, self-assembly.

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A novel DNA computing model based on RecA-mediated triple-stranded DNA structure

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Progress in Natural science:materials International 2007年第6期17卷 708-711页

作者： Fang Gang1, Zhang Shemin2. Dong Yafei1 and Xu Jin1(1. The Key Laboratory of Image Processing and Intelligent Control, Department of Control science & Engineering, Huazhong university of science and technology, Wuhan 430074, china 2. shaanxi university of technology, Hanzhong 72.000, china) Key Laboratory of Image Processing and Intelligent Control Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China shaanxi university of {2. Hanzhong 723000 China

The field of DNA computing emerged in 1994 after Adleman’s paper was published. Henceforth,a few scholars solved some noted NP-complete problems in this way. And all these methods of DNA computing are based on conventional Watson-Crick hydrogen bond of doublehelical DNA molecule. In this paper, we show that the triple-stranded DNA structure mediated by RecA protein can be used for solving computational problems. Sequence-specific recognition of double-stranded DNA by oligonucleotide-directed triple helix (triplex) formation is used to carry out the algorithm. We present procedure for the 3-vertex-colorability problems. In our proposed procedure, it is suggested that it is possible to solve more complicated problems with more variables by this model.

关键词： DNA computing 3-vertex-colorability problem.

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Effect of Strain on the Electrical Resistance of Carbon Nanotube/Silicone Rubber Composites

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Journal of Wuhan university of technology({2. science) 2011年第5期26卷 812-816页

作者：曾尤 school of materials {2. and Engineering Shenyang Jianzhu University

Carbon nanotube （CNT） filled silicone rubber （SR） composites were synthesized by in situ *** effect of strain on the electrical resistance of the CNT/SR composites and the structure evolution of CNT networks during tensile deformation were *** results showed that the CNT/SR composites had high sensitivity of resistance-strain *** a wide strain range （0-12.%）,the change of resistivity could reach 107,which was closely associated with the evolution process of the conductive CNT-network *** volume expansion of the composites in the tensile process led to a gradual decrease in the volume fraction of CNTs with the strain *** CNT loading was lower than the percolation threshold,CNT network was in disconnected state with a rapid increase in electrical resistance of the ***,the CNT loading had remarkable effect on the sensitivity of resistance-strain response in the composites.

关键词： carbon nanotubes silicone rubber composite resistance-strain response

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Theory of truth degrees of propositions in the logic system Ln^＊

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science in china(Series F) 2006年第4期49卷 471-483页

作者： LI Jun1,2.& WANG Guojun1,3 1. Institute of Mathematics, shaanxi Normal university, xi’an 710062. {2. 2. school of sciences, Lanzhou university of technology, Lanzhou 730050, {2. 3. Research Center for science, xi’an Jiaotong university, xi’an 710049, {2. Institute of Mathematics Shaanxi Normal University Xi’an China school of sciences Lanzhou University of Technology Lanzhou China Research Center for science Xi’an Jiaotong University Xi’an China

By means of infinite product of uniformly distributed probability spaces of cardinal n the concept of truth degrees of propositions in the n-valued generalized Lu- kasiewicz propositional logic system Ln^＊ is introduced in the present paper. It is proved that the set consisting of truth degrees of all formulas is dense in [0,1], and a general expres- sion of truth degrees of formulas as well as a deduction rule of truth degrees is then obtained. Moreover, similarity degrees among formulas are proposed and a pseudo-metric is defined therefrom on the set of formulas, and hence a possible framework suitable for developing approximate reasoning theory in n-valued generalized Lukasiewicz propositional logic is established.

关键词： truth degree similarity degree approximate reasoning.

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Preparation of TiO_2.thin film by the LPD method on functionalized organic self-assembled monolayers

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science china(Technological sciences) 2009年第1期52卷 137-140页

作者： HE ZhongLiang, YU ZhiWei, MIAO HongYan, TAN GuoQiang & LIU Yan school of materials {2. and Engineering, shaanxi university of science and technology, xi’an 71002., china school of materials {2. and Engineering Shaanxi University of Science and Technology Xi’an China

In this paper, uniform titania (TiO2. films have been formed at 50℃ on silanol SAMs by the liquid-phase deposition (LPD) method at a temperature below 100℃. OTS (Octadecyltrichloro-Silane) selfassembled monolayers (SAMs) on glass wafers were used as substrates for the deposition of titanium dioxide thin films. This functionalized organic surface has shown to be effective for promoting the growth of films from titanic aqueous solutions by the LPD method at a low temperature below 100℃. The crystal phase composition, microstructure and topography of the as-prepared films were characterized by various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicate that the as-prepared thin films are purely crystallized anatase TiO2.constituted by nanorods after being annealed at 500℃. The pH values, concentration of reactants, and deposition temperatures play important roles in the growth of TiO2.thin films.

关键词： TiO_2.thin film SAMs LPD anatase nanorod

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Effect of Lead Contents on the Properties of PMSZT Piezoelectric Ceramics

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Journal of Wuhan university of technology({2. science) 2007年第2期22卷 311-314页

作者：陆翠敏 school of materials {2. and Engineering Tianjin University of Technology

The effects of Pb content on crystallographic phase, microstructure, electric-properties of PMSZT piezoelectric ceramics were studied. The crystallographic phase and microstructure of the ceramics were examined by using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The experimental result shows that the samples consist of a mixture of tetragonal and rhombohedral phases in the range of lead contents x=0.95-1.06, grains grow up homogeneously and the minimum value of Curie temperature was obtained with x-=1.02. With Pb content x〈l.02.or x〉1.02. the Curie temperature moves towards a high temperature. A well-situated electric-properties of ET33/E0 （1660）, d33 （344pC/N）, Kp （0.684）, Qm （2.50）,tan 3（0.0030） were obtained when lead content x=1.02.

关键词： piezoelectric ceramics crystallographic phase microstructure electric-properties

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Two-Sublattice Thermodynamic Model on Carbonitride Precipitation in Microalloyed Steels Bearing Nb-V-Ti

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Journal of Iron and Steel Research International 2011年第S1期18卷 271-277页

作者： xiANG Song 1,3,LIU Guo-quan 2.(1.school of materials and Metallurgy,Guizhou {2.,Guiyang 550003,Guizhou,china 2.school of materials science and Engineering,{2. of science and technology,Beijing,Beijing 100083,china 3.The Key Laboratory for Mechanical Behavior and Microstructure of materials,Guizhou Province,Guiyang 550003,Guizhou,china) Guizhou Univ Sch Met & Mat Guiyang 550003 Guizhou Peoples R China Key Lab Mech Behav & Microstruct Mat Guiyang 550003 Guizhou Peoples R China Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

Based on the two sublattice model of the regular solution,one being metal atom sublattice and another being interstitial atom sublattice,a thermodynamic model for the precipitates of niobium carbonitride,vanadium carbonitride and titanium carbonitride was established to study the starting-temperature of precipitates and the austenite compositions at given temperature in a low carbon *** calculation results show that starting-temperature of the precipitation of niobium carbonitride,vanadium carbonitride and titanium carbonitride are 1100℃,92.℃ and 1340℃,respectively,the mole fraction of carbonitride precipitates is 8.65×10-4 in the 0.053C-0.002.N-1.2.Mn-0.008S-0.031Al-0.046Nb-0.008Ti0.02.V-Fe *** the N content is from 0.002.% to 0.0056%,the starting-temperature of the precipitation of the titanium carbonitride changes from 1340℃ to 1430℃.And the C content is from 0.053% to 0.07%,the startingtemperature of the precipitation of the titanium carbonitride hardly changes,but the atomic fraction of niobium in the carbonitride obviously increases.

关键词： microalloyed steel carbonitride precipitation two sublattice model thermodynamics

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Piezoresistivity of Carbon Fiber Graphite Cement-based Composites with CCCW

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Journal of Wuhan university of technology({2. science) 2011年第2期26卷 340-344页

作者：范晓明 school of materials {2. and Engineering Wuhan University of Technology

The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites（CFGCC） with carbon fiber content（1% by the weight of cement）,graphite powder contents （0%-50% by the weight of cement） and CCCW（cementitious capillary crystalline waterproofing materials,4% by the weight of cement） were *** experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation *** percolation threshold was about 2.%.A clear piezoresistive effect was observed in CFGCC with 1wt% of carbon fibers,2.wt% or 30wt% of graphite powders under uniaxial compressive tests,indicating that this type of smart composites was a promising candidate for strain *** measured gage factor （defined as the fractional change in resistance per unit strain） of CFGCC with graphite content of 2.wt% and 30wt% were 37 and 2.,*** the addition of CCCW,the mechanical properties of CFGCC were improved,which benefited CFGCC piezoresistivity of stability.

关键词： carbon fiber graphite cement-based composites cementitious capillary crystalline waterproofing materials electrical resistivity piezoresistivity

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Microstructural Features During Strain Induced Ferrite Transformation in 08 and 2.Mn Steels

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Journal of university of science and {2. Beijing 2001年第2期8卷 105-110页

作者： Ping Yang, Feng-e Cui, Fuming Wang (materials science and Engineering {2., university of science and technology Beijing, Beijing 100083, china) (Metallurgy {2., university of science and technology Beijing, Beijing 100083, china) materials Sci. and Eng. school University of Science and Technology Beijing 100083 China

The microstructure evolution during strain induced ferrite transformation was followed in thermal-simulation tests of clean 08 and 2.Mn steels. The influences of carbon equivalence and initial austenite grain size on ferrite grain refinement and the volume fraction of ferrite during straining were inspected. The results revealed that the accelerating effect of ferrite transformation by strain was increased as the carbon equivalence decreased. However, finer ferrite grains were obtained at higher carbon content. At strain of similar to1.5 ferrite grains less than 3 mum and 2.mum can be obtained in 08 and 2.Mn steels respectively. Whereas the ferrite grain refinement in 08 steel was due to both effects of strain induced transformation and ferrite dynamic recrystallization, that in 2.Mn was mainly due to strain induced transformation. Heavy strain can produce fine ferrite grains in coarse austenite grained 08 steel, but it would lead to band microstructure in coarse austenite grained 2.Mn.

关键词： clean carbon steel strain induced transformation grain refinement ferrite dynamic recrystallization

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Flotation Separating Rutile from Calcium and Silicon Gangue Minerals

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Rare Metals 2001年第4期20卷 205-208页

作者： Hao Ding1, HaiLin 2.1) Beijing Academy of Building materials, Beijing 100041, china 2. {2. of science and technology Beijing, Beijing 100083, china 北京建筑材料研究院北京 100041 北京科技大学北京 100083

Rutile separation from calcite, apatite and quartz by flotation was investigated. The results show that the rutile separation from calcium and silicon gangue minerals can be realized with alkyl-imino-bismethylene phos... 详细信息

关键词： rutile calcium and silicon gangue minerals flotation separate alkyl-imino-bismethylene phosphoric acid sodium hexametaphosphate

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