检索结果-南通市图书馆

The Role of Calcium in Microstructural Refinement of AZ91 Magnesium Alloy

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials {2.) 2006年第4期21卷 45-47页

作者：刘生发 school of Materials science and {2. Wuhan University of Technology Wuhan 430070China

The effect of calcium addition on the microstructures of AZ91 magnesium alloy was investigated. It was found that a small amount of calcium in AZ91 allay produced a large decrease in the α- Mg grain size and the dispersed fine β-Mgt7 Alt2.phases. In addition, some Al4Ca particles were found to exist in the AZ91 alloy containing 0.5wt% Ca. EDS analysis and water-quenched technique revealed that the grain-refining mechanism of calcium for the AZ91 alloys was mainly attributed to the role of restricting growth of calcium in the primary α-Mg crystals.

关键词： AZ91 magnesium alloy calcium microstructural refinement

Microwave Irradiation Treatment of Wood Flour and Its Application in PVC-Wood Flour Composites

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials {2.) 2007年第1期22卷 148-152页

作者：胡圣飞陈文 Institute of Materials science and engineering Wuhan University of Technology school of chemical and Environmental {2. Hubei University of Technology Wuhan 430068China

The technique of microwave irradiation induced free radical bulk- polyaddition reactions in porous wood flour was used to modify wood flour. The behaviors of the modified wood flour under microwave irradiation, such as thermal stability and moisture sorption properties, were studied. A kind of semiinterpenetrating polymer network wood four （Semi-IPN-WF） can be formed through polymerization of MMA in the porous wood flour by microwave irradiation, and the thermal decomposition temperature of the semi-IPN-WF is considerably increased. PVC/Semi-IPN-WF composites were prepared by melt mixing in double rolls, which exhibit improved rheological properties, lower water sorption properties and outstanding mechanical performances.

关键词： microwave irradiation wood flour poly(vinyl chloride) composites

Fabrication of copper (Ⅰ) nitride nanorods within SBA-15 by metal organic chemical vapor deposition

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2009年第2期52卷 352-356页

作者： ZHANG Ying1,2. Frank Leung-Yuk Lam2. YAN ZiFeng1 & HU XiJun2.1 school of Chemistry & chemical {2., china university of Petroleum, Dongying 2.7061, china 2.Department of chemical {2., Hong Kong university of science and technology, Hong Kong, china school of Chemistry & chemical {2. China University of Petroleum Dongying China Department of chemical engineering Hong Kong University of Science and Technology Hong Kong China

Copper (Ⅰ) nitride nanorods grown in channels of mesoporous silica SBA-15 by chemical vapor deposition method has been synthesized. The morphology and microstructure of the resulting product were characterized by XRD patters, TEM images, EDS analysis and Raman spectra. The XRD and TEM revealed that the Cu3N phase was confined in channels of SBA-15 forming continuous nanowires with 6 nm around and hundreds of nanometers in length. Raman spectra of the final product and pure Cu3N showed peaks shift due to the quantum confinement effect of the nanowires. This preparation methodology only requires a mild working condition and is capable of template synthesis of other binary nitride nanostructures with controlled morphology inside the channels of mesoporous materials.

关键词： nanorods copper nitride CVD SBA-15

Kinetic theory of self-condensing vinyl polymerization

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2010年第12期53卷 2429-2439页

作者： ZHOU ZhiPing 1 & YAN DeYue 2.1 school of Materials science and {2.,Jiangsu university,Zhenjiang 2.2.13,china 2.school of Chemistry and chemical {2.,Shanghai Jiao Tong university,Shanghai 2.02.0,china school of Materials science and {2. Jiangsu University Zhenjiang China school of Chemistry and chemical {2. Shanghai Jiao Tong University Shanghai China

This review introduces the kinetic theory of self-condensing vinyl polymerization (SCVP),including the SCVP of AB inimers,the SCVP with non-equal reactivity between A and B groups,the SCVP in the presence of a small amount of multifunctional initiators,also the SCVP of both inimers and *** analytical expressions of various molecular parameters for the resulting hyperbranched polymers,such as the molecular size distribution function,the average molecular weight,the polydispersity index and the degree of branching,are reviewed systematically.

关键词： kinetic theory self-condensing vinyl polymerization (SCVP) hyperbranched polymers

Wear Performance of Laser Surface Hardened GCr15 Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials {2.) 2010年第1期25卷 84-88页

作者：雷声 school of Materials science and {2. Hefei University of Technology Department of Electromechanical engineering Anhui Institute of Architecture and Industry

In order to assess the new tribological properties of laser surface hardened GCr15 steel, the wear resistance between specimens treated with laser and those of conventionally hardened under dry sliding conditions was compared. The change of wear mechanisms in laser hardened GCr15 resulted in a distinct difference in wear rates. The results showed that quenched zones not only had sufficient depth of hardening and higher hardness, but had more retained austenite and finer carbides because of a higher degree of carbide dissolution. Laser surface hardened GCr15 steel specimens exhibited superior wear resistance to their conventionally hardened specimens due to the effects of the microstructure hardening, high hardness and toughness. The wear mechanism for both the laser quenched layer and conventionally hardened layer was highly similar, generally involving adhesive, material transfer, wear-induced oxidation and plowing. When conventionally hardened block specimens rubbed against the laser hardened specimens, the surface of conventionally hardened block specimens was polished. The microstructural thermal stability was increased after laser surface treatment.

关键词： laser hardening dry sliding conditions GCr15 steel wear mechanisms

Magnesia Modification of Alkali-Activated Slag Fly Ash Cement

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of technology(Materials {2.) 2011年第1期26卷 121-125页

作者：沈卫国 Key Laboratory of Silicate Materials science and engineering of Ministry of Education Wuhan University of Technology school of Materials science and {2. Wuhan University of Technology

A new type of magnesia modification alkali-activated cement was prepared, the strength, setting time, shrinkage ratio and cracking behavior, as well as the composition and structure of the hydration product were investigated. The results indicate that the setting time of this cement is similar to that of the ordinary commercial cements; its strength reaches the standard of 42.5 degree cement, its cracking resistance has been remarkably improved because of the micro-aggregate effect of fly ash and shrinkage compensating of magnesia.

关键词： alkali-activated cement crack magnesia volume stability hydration

Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2.1 College of Mechanical engineering,Zhejiang university of {2.,Hangzhou 310032.china 2.school of Mechanical & Electronic engineering,Changchun university of science and {2.,Changchun 13002.,china College of Mechanical engineering Zhejiang University of Technology Hangzhou China school of Mechanical & Electronic engineering Changchun University of Science and Technology Changchun China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation

Surface Inspection System for Cold Rolled Strips Based on Image ProcessingTechnique

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 296-298页

作者： Ke Xu1 Jinwu Xu2.Shouli Lu1(l Material science and engineering {2., university of science and technology Beijing, Beijing 100083, china2.Mechanical engineering {2., university of science and technology Beding, Beliing 100083, china) Material science and engineering {2. University of Science and Technology Beijing Beijing 100083 China Mechanical engineering school University of Science and Technology Beijing Beijing 100083 China

A new surface inspection system for cold rolled strips based on image processing is introduced. The system is equipped withtwo different illumination structures and CCD matrix cameras. The structure and image processing of the inspection system are described. Some efficient algorithms for image processing and classification are presented. The system is tested with strip samples fromcold rolling plants. The results show that the system can detect and recognize six common defects of cold rolled strips successfully.

关键词： surface inspection system cold rolled strip image processing

Prediction of Dynamic Wellbore Pressure in Gasified Fluid Drilling

在线全文

学校读者我要写书评

暂无评论

Petroleum science 2007年第4期4卷 66-73页

作者： Wang Zhiming1,Ping Liqiu2.and Zou Ke2.(1. school of Petroleum engineering,Petroleum {2. of china,Beijing 102.49,china) (2. Institute of Drilling engineering technology,CNPC,Beijing 100097,china) Petr Univ china Sch Petr Engn Beijing 102249 Peoples R China CNPC Inst Drilling Engn Technol Beijing 100097 Peoples R China

The basis of designing gasified drilling is to understand the behavior of gas/liquid two-phase flow in the wellbore. The equations of mass and momentum conservation and equation of fluid flow in porous media were used to establish a dynamic model to predict wellbore pressure according to the study results of Ansari and Beggs-Brill on gas-liquid two-phase flow. The dynamic model was solved by the finite difference approach combined with the mechanistic steady state model. The mechanistic dynamic model was numerically implemented into a FORTRAN 90 computer program and could simulate the coupled flow of fluid in wellbore and reservoir. The dynamic model revealed the effects of wellhead back pressure and injection rate of gas/liquid on bottomhole pressure. The model was validated against full-scale experimental data,and its 5.0% of average relative error could satisfy the accuracy requirements in engineering design.

关键词： Gasified fluid drilling dynamic model pressure prediction model validation