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Redistribution of Boron during Ferrite Reaction in Nb-B Microalloyed Steel

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 223-227页

作者： Shanwu Yang Xinlai He(Applied science School, university of science and technology beijing, beijing 100083, China) Applied science School University of Science and Technology Beijing Beijing 100083 China

By contrast of microstructure and boron distribution in the same area of samples, the behavior of boronduring ferrite reaction in Nb-B microalloyed steel was studied. Boron atoms have segregated to original austeniteboundaries betfore ferrite reaction starts during isothermal treatment. The concentration of boron in small Pieces offerrite foming along austenite boundaries may be remarkably higher than that in austenite matrix, but it will reducegradually when the ferrite continuously grows. There is no obvious boron segregation on interface of γ/α and α/α.These facts indicate that ferrite growth is not controlled by diffusion of boron in austenite.

关键词： boron segregation ferrite reaction microalloyed steel

Theory for Constructing Generalized Synchronization and Applications

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 225-228页

作者： Xiaodan Zhang, Lequan Min (Applied science School, university of science and technology beijing, beijing 100083, China) Applied science School University of Science and Technology Beijing Beijing 100083 China

The approaches for constructing directionally coupled generalized synchronization (GS) systems are presented, which are available for the driving system and the respond system that are in GS via a given diffeomorphi... 详细信息

关键词： Chaos generalized synchronization predictability

Preparation of semi-solid AlSi7Mg alloy slurry with big capability

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Rare Metals 2010年第6期29卷 642-645页

作者： LI Sha and MAO Weimin School of Materials science and Engineering,university of science and technology beijing,beijing 100083,China School of Materials science and Engineering University of Science and Technology Beijing Beijing China

Semi-solid AlSi7Mg alloy slurry was prepared by low superheat pouring and weak traveling-wave electromagnetic *** effects of pouring temperature and stirring power on the microstructure of AlSi7Mg alloy slurry were *** results show that the semi-solid AlSi7Mg alloy slurry of 5 kg can be *** new technology can save energy and make the pouring process *** the pouring temperature is decreased at a stirring power of 0.41 kW,the shape of primary α-Al grains gradually changes from dendritic-like to *** the alloy melt is poured at the temperature（630°C） with a certain superheat,the pouring process becomes easier,and the spherical microstructure of AlSi7Mg alloy slurry can be prepared by the weak traveling-wave electromagnetic *** the pouring temperature is 630°C,increasing the stirring power appropriately can result in better spherical primary α-Al grains,but if the stirring power is increased to a certain value（1.72 kW）,the shape of primary α-Al grains does not obviously improve when the stirring power is continually increased.

关键词： aluminum alloys metal forming semisolid slurry electromagnetic stirring microstructure

Equilibrium Precipitation of Niobium Carbonitride in Austenite

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 119-122页

作者： Fuming Wang Wenchao Li(Applied science School, university of science and technology beijing, beijing 100083, China) Applied science School University of Science and Technology Beijing Beijing 100083 China

The equilibrium between niobium carbonitride and austenite has been studied. Experimentally, X-raydiffaction technique was adopted to verify that the precipitates have the same composition and structure. Theoretical-ly, Hillert and Staffansson's regular model about stoichimetric phase was used to describe the thermodynamic proper-ties of multi-component precipitate. Calculated results agree well with experimental values from literatures.

关键词： equilibrium niobium precipitate, austenite

NON-EQUILIBRIUM SEGREGATION OF Si ON Al-0.35 wt-% Si ALLOY SURFACE

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 98-101页

作者： CHEN Niug YU Zongsen university of science and technology beijing,beijing,China professor,Department of Materials Physics,university of science and technology beijing,beijing 100083,China beijing Univ of science and Technology Beijing China

Si segregation was observed in the vacancy condensation pits,formed by supersaturated vacancies beneath the oxidation layer of Al-0.35wt-％Si alloy,by optical microscopy,X- ray photoelectron spectroscopy and microhard... 详细信息

关键词： non-equilibrium segregation vacancy AI-Si alloy surface Si

A POSTERIORI ERROR ANALYSIS OF NONCONFORMING METHODS FOR THE EIGENVALUE PROBLEM

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Journal of Systems science & Complexity 2009年第3期22卷 495-502页

作者： Youai LiCollege of Computer and information Engineering, beijing technology and Business university, beijing100048,China. College of Computer and information Engineering Beijing Technology and Business University

This paper extends the unifying theory for a posteriori error analysis of the nonconformingfinite element methods to the second order elliptic eigenvalue *** particular,the authorproposes the a posteriori error estimator for nonconforming methods of the eigenvalue problems andprove its reliability and efficiency based on two assumptions concerning both the weak continuity andthe weak orthogonality of the nonconforming finite element spaces,*** addition,the authorexamines these two assumptions for those nonconforming methods checked in literature for the Laplace,Stokes,and the linear elasticity problems.

关键词： A posteriori error analysis eigenvalue problem nonconforming finite element.

Recycling of Spent Nickel-Cadmium Batteries

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International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 126-131页

作者： Xanghua Kong Pingnan Wu(Metallurgy School, university of science and technology beijing, beijing 100083, china) Metallurgy School University of Science and Technology Beijing Beijing 100083 China

A technique for recycling spent nickel-cadmium batteries, which makes separaion of cadmium and nickel possible, is developed by laboratory-scale experiments. NH3-H2CO3 aqueous solution was used in this leaching technique. Since neutralization and/or solvent extraction were not required in the separation procedure of nickel and cadmium, the closed systemizaion of the process becomespossible. Experimental results show that, (1) if the NH3 concentraion of leaching solution is sufficiently high and the ratio of H2CO3 toNH3 is properly adjusted, both Ni(OH)2 and Cd(OH)2 react with NH, and quickly dissolve into leaching solution, and (2) Ni(OH)2 can beconverted into insoluble NiO by calcination at 500℃, and CdO from Cd(OH)2 by calcination maintains good solubility in NH3-H2CO3aqueous solution. As a conclusion, the recycling technique characterized by two step leaching can be developed based on such changesin dissolution behavior by calcination. Meanwhile, the yields of 99.8% for nickel and 97.6% for cadmium are obtained, and the puritiesof Recycling of Spent Nickel-Cadmium BatterieRecycling of Spent Nickel-Cadmium Batteries Recycling of Spent Nickel-Cadmium Batteriesrecovered nickel and cadmium are 99.9% and 98.6%, respectively.

关键词： nickel-cadmium batteries recycling, ammonia leaching closed system environmental protection

SIZE DISTRIBUTION AND BEHAVIOUR OF VC PARTICLES IN FERRITIC NODULAR CAST IRON

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 92-97页

作者： WANG Yu SONG Weixi HAN Qiyong university of science and technology beijing,beijing,China The Institute of Precise and Special New Materials, university of science and technology beijing,beijing 100083,China beijing Univ of science and Technology Beijing China

Size distribution and precipitation of VC particles in ferritic nodular cast iron have been examined by techniques of ultrasonic screening,small angle X-ray scattering and chemical *** VC particles are sized over a wide *** superfine ones, dispersed in the ferritic matrix,are the majority.A saturated dispersion with ultrafine VC particles may be approached as the V content increasing in the ***5 seems to play an important role in the precipitation strengthening for ferritic nodular cast iron.

关键词： nodular cast iron ferrite size distribution VC particle

INFLUENCE OF INITIAL TEXTRUE ON THE COLD ROLLING TEXTURE OF Ti SHEETS

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中国有色金属学会会刊：英文版 1995年第2期5卷 66-70页

作者： Mao, Weimin Yu, Yongning Li, Botao(university of science and technology beijing, 100083 beijing) Univ of science and technology Beijing Beijing China

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关键词： Ti Rolling Texture ODF