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Mechanism of Cathode Process of B(Ⅲ) in LiF-NaF-KBF_4 Meltby Electrochemical Titration Technique

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International Journal of Minerals,Metallurgy and Materials 1998年第4期12卷 203-207页

作者： Qingrong Shi Xindong Wang Lianyu Yuan Shuzhen Duan(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 mechanism of cathode process of B(Ⅲ) at molybdenum and platinum electrodes in LiF-NaF-KBF4melt was studied and the transferred electron number of the reaction was calculated by means of cyclic *** effect of adsorption of electroactive component on the electrochemical response (e. g., the voltammetric i─Ecurves) was analyzed and discussed. The 'electrochemical spectra' for linear sweep voltammetry was used to elucidate the electrode reaction accompanied by a following transform process. The results show that the reduction ofB(Ⅲ) to B(0) proceeds in reversible one step three-electron reaction and the cathode process of B(Ⅲ) is affected byproduct adsorbed strongly at the electrode surface. It is assumed that the reduction and deposition of B(Ⅲ) at molybdenum and platinum electrodes proceed in two kinds of mechanism： (1) B(Ⅲ)＋ 3e = Bads→ B (surface diffusiondeposition mechanism) and (2) B(Ⅲ) ＋ 3e = B (direct deposition mechanism).

关键词： boron ions cathode process cyclic voltammetry fluoride melt

Structure and Formative Mechanism of Black Patina on Bronze Mirrors

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 147-155页

作者： Zhaozeng Ma Ling Du Xiulan Yin Lianji Jin Chunying Fang(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 formation of the black patina induced by soil humic asid under different conditions was studied, theblack, grey and brown colored shiny surfaces prepared in laboratory were analyzed. As a result the formation oftin-rich shiny black surface on bronze mirrors is the product of soil corrosion of the bronze mirrors. The patina isformed by reection between the alloy and the humic acid in soil, and leaching of copper and lead oxides through along period time when the mirrors were buried under the ground leaving a dense compact corrosion-resistant layerconsisted predominantly of stannic oxide microcrystal.

关键词： black patina on ancient bronze mirror humic acid soil corrosion, SnO_2 microcrystal

Precipitatation Behavior of FeTiP Phase in High Strength IF Steel

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 197-203页

作者： Zisu Zhao, Weimin Mao, Yongning Yu (university of science and technology beijing, beijing 100083, china) university of science and technology beijing Beijing 100083 China

The influence of chemical composition and annealing parameters on the behavior of FeTiP precipitation has been investigated. With increasing Ti content the yield strength and tensile strength were reduced, and the tendency of FeTiP precipitation became more remarkable. No FeTiP precipitate was observed and the best mechanical properties have been obtained in the steel sheet, of which the atom ratio of Ti to N is approximately equal to 1. In the temperature range of 700 to 800℃ the FeTiP precipitation could appear easily. The precipitation process was suppressed when the annealing temperature was below 600℃, and the FeTiP phase was dissolved above 900℃. The FeTiP precipitates would inhibit the migration of grain boundaries during the recrystallization in certain extent, and weaken the density of {111} fiber texture, which resulted in the reduction of r value. The relationship between composition and processing parameters, as well as their influence on the mechanical properties is discussed.

关键词： IF steel FeTiP precipitation

Fuzzy Pattern Recognition in Atlas and Images of the Unevenness of Carbide in Tool Steel

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Journal of university of science and technology beijing 2001年第3期8卷 234-236页

作者： Hui Zhang, Angui Li, Zhigang Zhang, Li Jiang Applied science school, university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing App Sci Sch Beijing 100083 Peoples R China

Fuzzy pattern recognition has been employed to identify some atlas and images of the unevenness of carbide in tool steel. Three models have been constructed. These models were based on fuzzy mathematics theory, as well as fuzzy pattern recognition method. Distribution rule of the unevenness of eutectic carbide in ledeburite steel is proposed in these models respectively.

关键词： fuzzy mathematics fuzzy and pattern recognition characteristic specimen

Kinetics of Evaporation of Zn and Pb from Carbon-bearing Pellets Made of Dust Containing Zn-Pb-Fe Oxides

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 178-183页

作者： Weiqing Chen, Dongyan Wang, Rongzhang Zhou, Zongcai Lin (Metallurgy school, university of science and technology beijing, beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

The influence of reduction temperature, size of coal powder and the carbon content on the evaporation rates of Zn and Pb in pellets made of ZnO-PbO-FeO bearing dust has been investigated between 1100-1300℃. The evaporation rate of Zn and Pb obtained from the experiments has been analyzed with kinetic models. The results show that the control step for evaporation of Zn is reduction reaction of ZnO by CO at the interface，and that the evaporation rate of Pb is controlled by the volatilization of reduction products, i.e. liquid lead. The overall apparent activation energies of Zn and Pb evaporation from the pellet are 79.42kJ/mol and 88.74kJ/mol respectively.

关键词： Zn-Pb-bearing dust carbon-containing pellet evaporation kinetics

EFFECT OF NITROGEN ON GRAPHITE MORPHOLOGY IN GRAY CAST IRON

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 151-155页

作者： ZHAI Qijie HU Hanqi university of science and technology beijing,beijing,china Faculty of Foundry,university of science and technology beijing,beijing 100083,china beijing Univ of science and Technology Beijing China

The distribution of N and morphology of graphite in gray cast iron containing N were studicd by adopting the man-made specimens of Fe-C-Si-Mn alloys with some N added. The N adsorbed along the interfaces between graphite and matrix together with solid- solutioned in graphite is believed to be the principal cause of morpholongical variation of graphite.

关键词： gray cast iron graphite morphology N

A new theorem to synchronization of unified chaotic systems via adaptive control

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Journal of university of science and technology beijing 2003年第6期10卷 72-75页

作者： Lequan Min and Jianyi JingApplied science school, university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing Appl Sci Sch Beijing 100083 Peoples R China

Chaos synchronization has been applied in secure communication, chemicalreaction, biological systems, and information processing. A new theorem to synchronization ofunified chaotic systems via adaptive control is proposed. The constructive theorem provides thedesign scheme for adaptive controller such that a respond system can synchronize with respect to anuncertain drive system. One example for discontinuous chaotic system is proposed to illustrate theeffectiveness and feasibility.

关键词： uncertain chaotic system adaptive control synchronization Chua's circuit

Modulated Quasi-plane Tunneling Current

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International Journal of Minerals,Metallurgy and Materials 1999年第1期13卷 44-46页

作者： peng Feng Wenmin Dai (china Center of Advanced science & technology (World Laboratory ) P.O. Box 8730, beijing 100080, china)(Applied science school, university of science and technology beijing, beijing 100083, china) china Center of Advanced science and technology (World Laboratory) P.O. Box 8730 Beijing 100080 China Applied science school University of Science and Technology Beijing Beijing 100083 China

A new tutmeling junction can be formed by an insulator layer inserting into a quantum well, and in the quantum well, a quasi-plane tunneling current can be formed by applying a tunneling voltage. If a P-N junction is grown on the quantum well, the tunneling current can be modulated by a P-N junction-bias voltage. The modulated quasi-plane tunneling current is not only related to the bias voltage, but also to the depth of the quantum well. It is analyzed that the P-N junction-bias voltage how to affect the tunneling current and a method of measuring the depth of the quantum well is presented.

关键词： quantum well tunneling current semiconductor device

Comparison of Ferrite Refinement Mechanisms by Different Processing Schedules in 08 and 20Mn Steels

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Journal of university of science and technology beijing 2001年第3期8卷 218-223页

作者： Ping Yang Feng’e Gui, Shicai Ma Material science and Engineering school, university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

The influence of deforming temperature on ferrite refinement was analyzed by comparing the microstructures obtained by deformation at above A(r3), in two-phase region of (alpha + gamma) and at below A(t) in clean 08 and 20Mn steels. The results indicate that ferrite refinement through strain induced transformation by deformation at above A(r3) is more effective than that by deformation simply through ferrite dynamic recrystallization. The main problem of ferrite refinement by deformation at below A(r3) is the inhomogeneity of microstructure which is controlled by the orientations and sizes of ferrite grains and the distribution of second phases. Ferrite dynamic recrystallization after strain induced transformation can further effectively refine ferrite.

关键词： clean carbon steel strain induced transformation grain refinement ferrite dynamic recrystallization