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Application of mesoscale modeling optimization to development of advanced materials

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Progress in Natural science:Materials International 2004年第8期14卷 8-15页

作者： SONG Xiaoyan(school of Materials science and engineering, beijing university of technology, beijing 100022, china) beijing Univ Technol Sch Mat Sci & Engn Beijing 100022 Peoples R China

The rapid development of computer modeling in recent years offers opportunities for materials preparation in a more economic and efficient way. In the present paper, a practicable route for research and development of advanced materials by applying the visual and quantitative modeling technique on the mesoscale is introduced. A 3D simulation model is developed to describe the microstructure evolution during the whole process of deformation, recrystallization and grain growth in a material containing particles. In the light of simulation optimization, the long-term stabilized fine grain structures ideal for high-temperature applications are designed and produced. In addition, the feasibility, reliability and prospects of material development based on mesoscale modeling are discussed.

关键词： mesoscale computer simulation Monte Carlo technique deformation recrystallization grain growth.

Robust Design for Generalized Minimum Variance Controllers

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 144-148页

作者： Heping Liu Xin Shim (Information engineering school, university of science and technology beijing, beijing 100083, china) (Shenyang Aircraft Corporation, Shenyang 110034, china) Information engineering school University of Science and Technology Beijing Beijing 100083 China Shenyang Aircraft Corporation Shenyang 110034 China

In order to improve the robustness and noise resistance of generalized minimum valance cothrol systems, several generalizedminimum variance control schemes are synthetically analyzed. The output variance caused by stochastic noise is decomposed to two parts. One part accords with the output variance of minboum vedance control and the other is the additional term of output variance causedby the control weighting factors. At the same time, the sensitivity function of modeling error is also deduced. A new robast design method that can minimize the sensitivity and the additional part of output variance is Presented by regulating variable parameters of contollers. The simulation results of self-tuning control show the effect of this method.

关键词： generalized minimum variance control variance robustness sensitivity

Interface reactions in film materials

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Journal of university of science and technology beijing 2003年第5期10卷 1-8页

作者： Fengwu Zhu, Zhonghai Thai, and Guanghua YuMaterials science and engineering school, university of science and technology beijing, beijing 100083, china Materials science and engineering school University of Science and Technology Beijing Beijing 100083 China

Interface reaction (IR) is a frequently observed phenomenon in the study ofadvanced thin film materials. It is very important to study the reaction conditions at which IRhappens and then to suppress or make use of it, the necessary conditions, including boththermodynamical and dynamical conditions of IR were discussed in detail. IRs in various systems,including oxide/silicon, oxide/metal, metal/metal, metal/semiconductor andsemiconductor/semiconductor, were reviewed. Methods to suppress and make use of IR were alsointroduced.

关键词： interface reaction spin-valve multilayers gate dielectric

Fractal structure reconstruction for alumina-silicate refractory fiber and simulation of the thermal conductivity

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Journal of Thermal science 2010年第1期19卷 80-86页

作者： XIA Dehong,GUO Shanshan,and Ren Ling Department of Thermal engineering,university of science and technology beijing,beijing 100083,china Department of Thermal engineering University of Science and Technology Beijing Beijing China

In this paper, it is proved that the intemal porous structure of alumina-silicate refractory fiber has fractal characteristics, which is reconstructed by the computer and the reconstructed structure further proved to have fractal characteristics. Based on the reconstructed structure, the network-thermal-resistance model is established to calculate the thermal conductivity of the fiber. It is shown that the calculated results agree well with the previous experimental ones, proving the correctness of the method.

关键词： fractal refractory fiber thermal conductivity

Feasibility Study on Continuous Mining Method in Deep Position of Jinchuan Nickel Mine, china

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Journal of university of science and technology beijing 2001年第2期8卷 81-85页

作者： Meifeng Cai, Lan Qiao, Changhong Li, Shuanghong Wang (Civil and Environmental engineering school, university of science and technology beijing, beijing 100083, china) Univ Sci & Technol beijing Civil & Environm Engn Sch Beijing 100083 Peoples R China

Jinchuan nickel mine is the largest nickel mine in china. Cut-and-fill mining method with high density cementing materials is used in the mine. The original mining design divided the mining operation into two steps. The first step stopped the mining rooms and the second step stopped the pillars. Because the two-step method made big trouble for finally mining pillars and strongly limited the mining speed and production, it was successfully changed to a continuous cut-and-fill method without pillars. However, the mining operation in the mine has been down to 800 m and the mining condition is getting worse and more complicated. Through systematical field investigations and 3-D FEM analysis, it is proved that the mining method without pillars is feasible for mining deeper orebodies in Jinchuan nickel mine.

关键词： Jinchuan nickel mine deep position continuous mining feasibility study

Reaction Sintering of Fe-Al Powder Mechanically Activated

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 233-236页

作者： Chengchang jia Xiaosen Lu Jun Zhao Zizhang Xie(Material science and engineering school, university of science and technology beijing, beijing 100083, china) (beijing Hard Metal Factory, beijing 100055, china) Material science and engineering school University of Science and Technology Beijing Beijing 100083 China beijing Hard Metal Factory Beijing 100055 China

The mixture of Fe and Al powder was mechanically activated and sintered to study a non-melting methodof producing the intermetallics Fe3Al. High-energy ball milling was used as an activation method, X-ray diffractionand SEM were chosen to analyze the materials variation before and after activation and sintering, and hot press ofFe-Al powder was inveshgated to compare mechanical activation with sintering. The results show that combiningmechanical activation with reaction sintering can complete the transformation from pure Fe and Al powder to intermetallics. It is difficult to do the transformation by either mechanical activation or hot press.

关键词： intermetallic compound sintering metal powder mechanical activation

Electrochemical Characteristic of Decarburization Reaction

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 27-30页

作者： Xionggang Lu Fushen Li Lifen Li Kouchih Chou (Applied science school, university of science and technology beijing, beijing 100083, china)(Material science and engineering school, Shanghai university, Shanghai 200072, china) Applied science school University of Science and Technology Beijing Beijing 100083 China Material science and engineering school Shanghai University Shanghai 200072 China

The electrochemical mechanism of the reaction between Fe-C melts and CaO-SiO2-Al2O3-FeOx slag systems has been carried out. The experimental results suggest that the final content of carbon in melt increases as the partial oxygen pressure of gas decreases no matter whether there is electronic conductor or not. However, the final content of carbon in the system with electronic conductor is much lower than that without electronic conductor. It can be deduced that the transfer ability of oxygen in slag is dominated by electrons. When an electronic conductor exists, an easy pathway for the electrons is provided and the oxygen transfer rate is accelerated.

关键词： melt-slag reaction decarburization electrochemistry electronic conductor

Simulation of Vertical Planetary Mill Based on Virtual Prototyping

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Journal of university of science and technology beijing 2001年第2期8卷 86-90页

作者： Ruitao Li, Mei Fang, Wenming Zhang, Yue Ma (Civil and Environmental engineering school, university of science and technology beijing, beijing 100083, china) Univ Sci & Technol beijing Civil & Environm Engn Sch Beijing 100083 Peoples R China

The mechanical model of vertical planetary mill is set up, whose dynamic and kinetic characteristics are described as well. Based on the analysis of system dynamics of vertical planetary mill, virtual prototyping technology is applied in the simulation of this mill. The development of virtual prototype of equipment, virtual test and optimization of virtual prototype are stated in detail. Some useful conclusions which have theoretical meaning for the manufacturing of vertical planetary mill have been obtained. Furthermore, it is pointed out that virtual prototyping technology shows great advantage and is bound to become a main method of developing product in the future.

关键词： virtual prototype vertical planetary mill dynamics simulation ADAMS

Synthesis of Zeolites by Alkaline Activation of Fly Ash

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Journal of university of science and technology beijing 2001年第3期8卷 161-163页

作者： Hua wang, Qiang Zhang, Cunyi Song, Fengmei Liu Civil and Environmental engineering school, university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing Sch Civil & Environm Engn Beijing 100083 Peoples R China

In terms of mineral transformation, and chemical composition of acid-soluble component as a function of reaction time, the effect of alkaline solution on zeolite-like fly ash was studied by employing fly ash and NaOH solution as starting materials. When fly ash and 1-10 mol/L NaOH solution were processed at 100 degreesC for 24 h with 1:10 W/S ratio in a relatively closed system, powder XRD patterns of resulting products indicated the formation of various zeolites. Zeolite P crystallized early at low alkaline concentration, which was replaced then by zeolites X and A. At high concentration, hydroxy sodalite was the only new phase. Quartz, in fly ash and NaOH solution system, gradually dissolved, and mullite, however, remained stable. It was concluded that, with Al/Si and Na/Si finally reaching equilibrium in molar ratio, composition of starting mixtures affects the crystallization of zeolite from fly ash.

关键词： fly ash alkaline solution zeolite