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Journal of university of science and technology beijing 2004年第3期11卷 235-239页

作者： Yan Huang Hong Qiu Liqing Pan Yue Tian Fengping Wang Ping Wu department of Physics, applied science school, university of science and technology beijing, beijing 100083, china Dept. of Phys. Appl. Sci. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

110 nm-thick Au layers were sputter-deposited on unheated glasses coatedabout a 10 nm-thick and a 50 nm-thick Cr layer respectively. The Au/Cr bilayer films were annealedin a vacuum of 1 mPa at 300℃ for 2, 5 and 30 min, respectively. Auger electron spectroscopy, X-raydiffraction and Field emission scanning electron microscopy were used to analyze the composition andstructure of the Au layers. The resistivity of the bilayer films was measured by using four-pointprobe technique. The adhesion of the bilayer films to the substrate was tested using tape tests. Theamount of Cr atoms diffusing into the Au layer increases with increasing the annealing time,resulting in a decrease in lattice constant and an increase in resistivity of the Au layer. Thecontent of Cr inside the Au layer grown on the thinner Cr layer is less than that grown on thethicker Cr layer. For the Au/Cr bilayer films, the lower resistivity and the good adhesion to theglass substrate can be obtained at a shorter annealing time for a thinner Cr layer.

关键词： Au/Cr bilayer film Cr layer thickness annealing characteristic

CALCULATING MODELS OF MASS ACTION CONCENTRATIONSFOR MATTES (Cu_2S-FeS-SnS)INVOLVING EUTECTIC

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 392-397页

作者： J. Zhang (department of Metallurgy, university of science and technology beijing, beijing 100083, china) Univ of science and technology Beijing Beijing China

Based on the facts that cations and anions of molten salts and binary basic oxide solid solutions do not separate from each other as well as that the electric conductivities of mattes are greater than that of salts and basic oxide solid solutions, the calculating models of mass action concentrations for binary and ternary mattes involving eutectic have been formulated. The results of calculation agree well with the values measured;this in turn shows that the calculating models can reftect the structural characteristics of the mattes concerned.

关键词： matte activity eutectic mass action concentration

Crystallization Mechanism of Na_2O-CaO-Al_2O_3-SiO_2-F Glass Containing Cr_2O_3

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 214-218页

作者： Lidong Teng Fuming Wang Wenchao Li(department of inorganic Materials, Shandong Institute of Light Industry, Jinan 250100, china)(applied science school, university of science and technology beijing, beijing 100083, china) department of Inorganic Materials Shandong Institute of Light Industry Jinan 250100 China applied science school University of Science and Technology Beijing Beijing 100083 China

The effect of Cr2O3 on the nucleation and crystallization of Na2O-CaO-Al2O3-SiO2-F- glass has been investigated by means of ESR(Electron Spin Resonance), SEM(Scanning Electron Microscope), EDS(Energy Dispersive Specrometer) and so on. Computer pattern recognition is applied to optimize the heat-treatment schedules. The experimental results show that the base glass containing more than 1 .5 % (mass fraction) Cr2O3 can be nucleated internally and converted to spheroidal crystal glass materials. The spheroidal crystal consisted of fibrous wollastonite crystals radiating from a center. The residual glass phase filled in the interstices between the fibers and between the spherulites. During heat treatment process, the valence states ofchromium changed from Cr6- to Cr3-, and the Cr-spinel solidsolution [CaCr2O4] precipitated followed this valence change. At the primary stage of crystallization, the Cr-spinel could act as a nucleating center on which the principal or}stalline phase β-CaSiO3 grew epitaxially.

关键词： crystallized glass Na_2O-CaO-Al_2O_3-SiO_2 Cr_2O_3 pattern recognition

A WT-STFT combining Algorithm

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 315-317页

作者： Xisheng Li, Shaochun Wang (Information Engineering school, university of science and technology beijing, beijing 100083, china) Information Engineering school University of Science and Technology Beijing Beijing 100083 China

A fast wavelet packet (WP) algorithm is presented, in which the wavelet transform (WT) and the short-time Fourier transform (STFT) are combined. As WT produces multiresolution of frequency and time, and STFT has a fas... 详细信息

关键词： signal processing, wavelet transform short-time Fourier transform Informatid

Discrepancy of the magnetic behaviors and crystalline structure on the Co/FeMn and FeMn/Co interfaces with ultrathin Pt spacer

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Rare Metals 2010年第5期29卷 473-479页

作者： LIU Yang,FU Yanqiang,JIN Chuan,and FENG Chun department of Materials Physics and chemistry,university of science and technology beijing,beijing 100083,china department of Materials Physics and chemistry University of Science and Technology Beijing Beijing China

The exchange coupling at the ferromagnetic/antiferromagnetic （FM/AFM） interface is influenced by both the magnetic structure and the crystalline micro-structure. Co/FeMn/Co thin films with 0.4 nm Pt spacer layer inserted into the Co/FeMn and FeMn/Co interface respectively were deposited by means of magnetron sputtering. The two interfaces upon and beneath the FeMn layer show distinct behaviors before and after the Pt spacer inserted. There is a remarkable shrink of the interracial uncompensated spins within the FeMn bottom interracial monolayers, whereas a relaxation of the pinning strength of the FeMn interfacial spins along the out-of-plane direction occurs at the top in- terface. XRD analysis indicates the Pt layer upon the FeMn layer forms an fcc （002） texture, implying the magnetic discrepancy between the top and bottom FeMn interfaces has crystalline structural origins.

关键词： interfaces exchange coupling exchange bias spacer stress anisotropy lattice match

High Temperature Ductility Loss of 16MnCr5 Pinion Steels

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 123-128页

作者： Haiwen Luo Pei Zhao Zijiu Dang(Metallurgy school, university of science and technology beijing, beijing 100083, china) Metallurgy school University of Science and Technology Beijing Beijing 100083 China

A wide ductility trough covering from 700 to 1100 is observed in the curve of Reduction of Area (RA) *** for 16MnCr5 pinion steel. At 750℃, corresponding to the minimum of RA, it is grain boundary slidingthat controls its hot ductility rather than usual Deforming Induced Ferrite (DIF), which can only appear just below750℃ and slightly improve hot ductility. The volume fraction of ferrite is dependent on the strain and strain *** a critical strain must be necessary for formation of DIF then with strain rate increasing, the volume fractionof DIF decreases but RA is elevated. In the γ phase region, hot ductility is seriously deteriorated because of grainboundary sliding promoted by oxidcs and sulfides at the grain boundary and recovered because of dynamic recrystal-lization at higher temperature; when strain rate increases, ductility is improved as there is insufficient time for cracksto propagate along the γ grain boundary as well as dynamically precipitating, and ductility trough becomes narrowerbecause the temperature for onset of dynamic recrystallization decreases. In addition, γ→α phase transformationintroduced by temperature drop before the tensile test encourages precipitation of AlN and impairs ductility.

关键词： hot ductility deforming induced ferrite grain boundary sliding precipitates

Effect of powder mixing process on the microstructure and thermal conductivity of Al/diamond composites fabricated by spark plasma sintering

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Rare Metals 2010年第1期29卷 86-91页

作者： CHU Ke, JIA Chengchang, LIANG Xuebing, and CHEN Hui 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

Two powder mixing processes, mechanical mixing （MM） and mechanical alloying （MA）, were used to prepare mixed Al/diamond powders, which were subsequently consolidated using spark plasma sintering （SPS） to produce bulk Al/diamond composites. The effects of the powder mixing process on the morphologies of the mixed powders, the microstructure and the thermal conductivity of the composites were investigated. The results show that the powder mixing process can significantly affect the microstructure and the thermal conductivity of the composites. Agglomerations of the particles occurred in mixed powders using MM for 30 min, which led to high pore content and weak interfacial bonding in the composites and resulted in low relative density and low thermal conductivity for the composites. Mixed powders of homogeneous distribution of diamond particles could be obtained using MA for 10 min and MM for 2 h. The composite prepared through MA indicated a high relative density but low thermal conductivity due to its defects, such as damaged particles, Fe impurity, and local interfacial debonding, which were mainly introduced in the MA process. In contrast, the composite made by MM for 2 h demonstrated high relative density and an excellent thermal conductivity of 325 W.m^-1.K^-1, owing to its having few defects and strong inter-facial bonding.

关键词： metal matrix composites thermal properties sintering powder mixing

Effect of coherent-light phase on tunneling process

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Journal of university of science and technology beijing 2003年第4期10卷 61-64页

作者： Peng Fengapplied science school, university of science and technology beijing, beijing 100083, china Univ Sci & Technol beijing Appl Sci Sch Beijing 100083 Peoples R China

The coherent-light-driven tunneling in double quantum wells has been *** electrons are coupled to a system of phonons and subjected to the two beams of coherentlyoptical waves. By adopting a gauge to both the external field and the phonon field, the phonon fieldoperators in the Schrodinger equations are eliminated. In this way, an expression of the tunnelingcurrent is conveniently derived considering the relaxation effect. It is shown that under theintense laser field, the tunneling current oscillates rapidly with time at low temperature. Theduration of the oscillations is related to the temperature. By adjusting the phase difference of thetwo light-beams, the oscillation frequency can be modulated.

关键词： tunneling current quantum wells gauge transformation

Application of Diagonal Recurrent Neural Network toDC Motor Speed Control Systems

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 68-71页

作者： Jing Wang Hui Chen Information Engineering school, university of science and technology beijing, beijing 100083, china Information Engineering school University of Science and Technology Beijing Beijine 100083 China

A new kind of dynamic neural network--diagonal recurrent neural network (DRNN) and its learning method and architecture are presented. A direct adaptive control scheme is also developed that is applied to a DC (Direct Current) speed control system with the ability to auto-tune PI (Proportion Integral) parameters based on combining DRNN with PI controller. The simulation results of DRNN show better control performances and potential practical use in comparison with PI controller.

关键词： diagonal recurrent neural network PI controller DC Motor speed control system

Multimedia Data Coding and its Development

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International Journal of Minerals,Metallurgy and Materials 2000年第3期14卷 229-232页

作者： Xingye Yu, Yang Yang (Information Engineering school, university of science and technology beijing, beijing 100083, china) Information Engineering school University of Science and Technology Beijing Beijing 100083 China

The requirements of data coding in multimedia applications are presented, the current technique of coding and relative standards is introduced, then the work that have been doing is presented, i.e. the wavelet-based coding method and the VE (Visual Entropy)-based coding method. The experiment results prove that these methods have gained a better perceptual quality of a reconstructed image and a lower bit rate. Their performance evaluations are better than JPEG (Joint Photographic Experts Group) coding. Finally, the future topics of study are put forward.

关键词： multimedia data coding MPEG (Moving Picture Experts Group) VE (Visual Entropy)