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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,{2., 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

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 {2. and Engineering,university of {2. and technology beijing,beijing 100083.china school of materials {2. 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

Microstructure Characteristics and Apparent Viscosity of Hypereutectic Al-2.%Si Alloy Melt During Semi-solid State Stirring

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Journal of university of science and technology beijing 2001年第2期8卷 126-128页

作者： Yanjun Li, Weimin Mao, Zisheng Zhen, Xueyou Zhong (material science and Engineering {2., university of science and technology beijing, beijing 100083. china) material Sci. and Engineering school University of Science and Technology Beijing 100083 China

The microstructural evolution and apparent viscosity of hypereutectic Al-2.%Si alloy during semi-solid state shearing were studied with a Searte type viscometer. When the alloy melt was continuously stirred from 72. degreesC to eutectic temperature, the primary Si crystals were gradually changed from elongated platelets to near-spherical shapes. It was found that some nondendritic a-phase formed when the melt was stirred below 585 degreesC. The experiment showed that the semi-solid stirring had strong effect on inhibiting the anisotropic growth of Si crystals during solidification. The apparent viscosity of the alloy melt increased slowly with the decreasing of temperature before the formation of nondendritic alpha -phase, which caused the dramatic increase of apparent viscosity.

关键词： hypereutectic Al-Si alloy solidification structures apparent viscosity

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,{2., 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

Producing Calcium-Bearing Mullite Thermal-Insulating Refractories by Kyanite

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International Journal of Minerals,Metallurgy and materials 1999年第1期13卷 50-53页

作者： Wen Ni (Resources Engineering school, university of science and technology beijing,{2.) Resources Engineering school University of Science and Technology Beijing Beijing 100083 China

To improve the physical properties, a series of experiments have been camed out to produce calcium-bearing mullite thermal-insulating refractories by using kyanite as major raw materials. The experiments were carried out by a foaming technique and using white cement as a combing agent. The results show that the calcium-bearing mullite refractory has much better physical properhes than traditional clay refractory and high-alumina refractory.

关键词： mullite thermal-insulating refractory kyanite

A New Safety Electric Initiating System

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 306-308页

作者： Daze Lin(Resource Engineering school, university of science and technology beijing,{2.) Univ of science and technology Beijing Beijing China

Based on the analysis of weakness on the safety of traditional electric detonators, a BJ-l safety electric detonator initiatingsystem and its corresponding safe examination technique were successfully developed. By leading false foot wires and taking advantageof the transmitting frequency band of Mo-Zn ferrite, detonators in this new system can completely impede the direct induction of outsidecrosstalk that may cause casual firing in the ordinary as well as eleclromagnetic ones. Possible causality by lightning was discussed. Results are presented, of its safety tests on resistance to direct and alternating current, electrostatic, and crosstalk induced by damp leakagein saturated salty water.

关键词： electric detonator blasting engineering, electric initiating system, safety

CABOSFV algorithm for high dimensional sparse data clustering

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Journal of university of science and technology beijing 2004年第3期11卷 283-288页

作者： Sen Wu Xuedong Gao Management school, university of science and technology beijing,{2. Mgmt. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

An algorithm, Clustering Algorithm Based On Sparse Feature Vector (CABOSFV),was proposed for the high dimensional clustering of binary sparse data. This algorithm compressesthe data effectively by using a tool 'Sparse Feature Vector', thus reduces the data scaleenormously, and can get the clustering result with only one data scan. Both theoretical analysis andempirical tests showed that CABOSFV is of low computational complexity. The algorithm findsclusters in high dimensional large datasets efficiently and handles noise effectively.

关键词： clustering data mining sparse high dimensionality

Calculation Models of Mass Action Concentrations for Metallic Melts Involving Monotectic

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Journal of university of science and technology beijing 2001年第4期8卷 248-253页

作者： Jian Zhang Metallurgy school, university of science and technology beijing,{2. Metallurgy school University of Science and Technology Beijing Beijing 100083 China

Based on the phase diagrams, measured activities as well asDeltaG(m) and DeltaG(xs), calculating models of mass action concentrations for metallic melts involving monotectic have been formulated. The calculated results agree with practice on the whole, showing that the models deduced generally can reflect the structural characteristics of these melts. The metastable compounds formed in the melts are of the types A(2.B(3), AB(2., A(2.B(3) or AB and A(2.B(3)+AB etc..

关键词： metallic melts monotectic activity mass action concentration

New templates of CNN for extracting corners of objects in gray-scale images

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Journal of university of science and technology beijing 2003年第3期10卷 73-75页

作者： Lequan Min, Ming Lei, and Xisong DongApplied science school,{2., beijing 100083. china Appl. Sci. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

A new cellular neural network (CNN) with nonlinear templates is presented forextracting convex corners of objects in gray-scale images. Application examples showed that the newCNN can even detect convex corner charact... 详细信息

关键词： cellular neural network extract convex comers gray-scale images