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Melt Synthesis and Characterization of Poly(L-lactic Acid) Chain Linked by Multifunctional Epoxy Compound

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Journal of Wuhan university of Technology(Materials science) 2010年第5期25卷 774-779页

作者：王远亮 Research Center of Bioinspired Materials science and engineering Bioengineering College Chongqing University

High molecular weight（Mw） poly（L-lactic acid）s（PLLAs） were synthesized using multifunctional epoxy compound（Joncryl-ADR4370） as chain extender. The products were characterized by gel permeation chromatography（GPC） and spectroscopy（1HNMR and FTIR）. The results indicated that the Mw of PLLA increased with the increasing of the ratio of epoxy compound and the extending of reaction time. The highest Mw of PLLA reached 360 000 g/mol when the ratio of epoxy compound was 1.5 wt%. However, the reactants turned to cross-linking when the ratio of epoxy compound was over 1.5 wt%. Differential scanning calorimetry（DSC） measurements demonstrated that the glass transition（Tg） and melting temperatures（Tm） of products increased slightly as the increase of the molecular weight. Analysis of the hydrolytic degradation in vitro showed that the branched PLLA possessed the quicker degradability than that of the linear PLLA.

关键词： melt synthesis poly(lactic acid) epoxy compound chain extender

Density Measurement of Liquid Ni-Ta Alloys by a Modified Sessile Drop Method

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Journal of Wuhan university of Technology(Materials science) 2005年第2期20卷 67-70页

作者：方亮 Department of Applied Physics Chongqing UniversityChongqing 400044 China Satellite Venture Business Laboratory Kyushu Institute of TechnologyKitakyushu 804-8550Japan Assoc.Prof

The density of liquid Ni-Ta alloys was measured by using a modified sessile drop method. It is found that the density of the liquid Ni-Ta alloys decreases with the increasing temperature, but increases with the increase of tantalum concentration in the alloys. The molar volume of liquid Ni-Ta binary alloys increases with the increase of temperature and tantalum concentration.

关键词： Ni-Ta alloy density modified sessile drop method molar volume tantalum concentration

Synthesis of New Polyether Polycarboxylate Superplasticizer

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Journal of Wuhan university of Technology(Materials science) 2010年第5期25卷 799-802页

作者：麻秀星 Materials College Chongqing University Xiamen Academy of Building Research Group

The effects of various factors on the synthesis process and the performances of product, including batch feeding way and the dosage of the radical initiator, the system concentration, the reaction temperature and the reaction time were discussed. A kind of polycarboxylate superplasticizer with allyl alcohol polyethylene glycol, maleic anhydride and methacrylic acid sulfonic sodium as main raw materials has been synthesized. Their relative effectiveness as dispersants was evaluated in cement paste by measuring paste fluidity. The optimum parameters of technology and the appropriate proportion of raw materials were obtained. As a result,the new high performance superplasticizer suitable for high-performance concrete has been synthesized. The structure of copolymer was characterized and analyzed by FT-IR spectra. Results indicated that product copolymer structure was consistent with the ideal molecular structure designed.

关键词： polycarboxylate maleic anhydride high-performance superplasticizer free radical polymerization

Experimental Study about Activated Water Generated by the Electro-hydraulic Impulse Strengthening the mechanical Performance of Concrete

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Journal of Materials science & Technology 2002年第4期18卷 290-292页

作者： Shijin ZHANG, Zhenfang LIAO and Changlin YANGCollege of mechanical engineering, {2. university, {2. 400044, china chongqing Univ Coll Mech Engn Chongqing 400044 Peoples R China

On the basis of a great number of experiments, it is proved that the strength of concrete is improved greatly when it is mixed with activated water produced by the electro-hydraulic impulse. With the proper parameters, the compression strength of concrete can be increased by 45%. The reason for improvement of concrete strength by using activated water is discussed from the aspect of the structure of molecule.

关键词： Concrete Electro-hydraulic impulse Activated waterx

Persistence of bounded solutions to degenerate Sobolev-Galpern equations

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science china Mathematics 2010年第11期53卷 2831-2846页

作者： ZHU ChangRong1 & ZHANG WeiNian2. 1school of Mathematics, chongqing {2., chongqing 400044, china 2.angtze Center of Mathematics and Department of Mathematics, Sichuan {2., Chengdu 610064, china 1. school of Mathematics Chongqing University Chongqing 400044 China2. Yangtze Center of Mathematics and Department of Mathematics Sichuan University Chengdu 610064 China

In this paper the persistence of bounded solutions to degenerate evolution equations of Sobolev-Galpern type is discussed. In order to define the evolution operator well, we study the existence and uniqueness of solutions to its linear form. On this basis we discuss exponential dichotomies of the evolution operator and give the Fredholm alternative result for bounded solutions of nonhomogeneous linear degenerate equations. This result enables us to give a condition for the persistence of bounded solutions of a general degenerate nonlinear autonomous equation under a nonautonomous perturbation.

关键词： degenerate evolution equation Sobolev-Galpern type boundedness Fredholm alternative exponential dichotomy

Rock matrix-fractured media model for heterogeneous and fractured coal bed

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中国有色金属学会会刊：英文版 2011年第S3期21卷 621-625页

作者： ZHANG Chun-hui1, YU Guang-ming2. ZHANG Chun1 1. school of Civil engineering, Hebei {2. of science and Technology, Shijiazhuang 050018, china 2. school of Civil engineering, Qingdao Technological {2., Qingdao 2.6033, china [a] school of Civil engineering Hebei University of Science and Technology Shijiazhuang 050018 China [b] school of Civil engineering Qingdao Technological University Qingdao 266033 China

Coal was considered rock matrix-fractured media composed of rock matrix and fractures, and the rock matrix-fractured media model for heterogeneous and fractured coal bed was presented. In this model the rock matrix is heterogeneous, and the mechanical parameters such as elastic modulus and strength follow Weibull distribution. Fractures in coal bed were generated with the discrete fracture network method, and the properties of fractures were simulated with Desai element. Then the virtual generating system (VGS) of natural heterogeneous and fractured coal bed was developed in Matlab 6.0. The coupled model of gas flow and deformation process based on the rock matrix-fractured media model method and VGS for heterogeneous and fractured coal bed was presented, and the numerical code was developed in Matlab 6.0. The gas flow process in the heterogeneous and fractured coal bed was simulated in a numerical case. The main conclusions are: 1) The natural heterogeneous and fractured coal bed could be simulated by the rock matrix-fractured media model and VGS; 2. The fractures connected with the well have much more effects on gas flow than those non-connected.

关键词： heterogeneity fractures rock matrix-fractured media

Surface Inspection System for Cold Rolled Strips Based on Image ProcessingTechnique

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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 {2. 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

Ni60-SiC Coating Prepared by Plasma Spraying, Plasma Re-melting and Plasma Spray Welding on Surface of Hot Forging Die

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Journal of Wuhan university of Technology(Materials science) 2011年第4期26卷 715-718页

作者：王洪福 school of mechanical {2. and Automation North University of China

In order to produce the hear-resistant inner layer of hot-forging die, plasma spraying and plasma re-melting and plasma spray welding were adopted. Substrate material was W6Mo5Cr4V2. including 10%, 2.%, 30% SiC ceramic powder used as coating material to obtain different Ni-based SiC alloys coating. Micro-structure and micro-hardness analysis of the coating layer were followed, as well as thermophysical properties for the coating layer were measured. The experimental results show that the coating prepared with 70% Ni60, 30% SiC powder has best properties with plasma spray welding, in which the micro-hardness can achieve 1100 HV, meanwhile can improve the thermal property of hot-forging die dramatically.

关键词： hot forging die plasma spraying plasma re-melting plasma spray welding thermo- physical properties

Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

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science china Chemistry 2006年第4期49卷 296-307页

作者： LI Ming1, ZHENG Wenxu2.& TIAN Anmin2.1. Department of Chemistry, Southwest-china Normal university, {2. 400715, china 2. Department of Chemistry, Sichuan university, Chengdu 610064, china 1. Department of Chemistry Southwest-China Normal University Chongqing 400715 China 2. Department of Chemistry Sichuan University Chengdu 610064 China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31g(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.