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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

NONEL High Precision MS Delay Detonator

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Journal of university of science and technology beijing 2001年第3期8卷 164-166页

作者： Daze Lin, peng Yang Civil and Environmental Engineering School, university of science and technology beijing, beijing 100083, china Civil and Environmental Eng. School Univ. of Science and Tech. Beijing Beijing 100083 China

The NONEL high precision MS Delay Detonator (FDG-1detonator) is introduced. The main aspects about the FDG-1 detonator include the choice of structure, delay composition, control of the gas chamber, optimum charge and density, suitable explosives per meter in the NONEL tube, base firing charge and the main specifications. The improvement of the characteristics of FDG-1 detonator has been tested systematically. The testing method is reliable and its precision can meet the demand for usage.

关键词： NONEL high precision MS Delay Detonator delay time

H~∞ Theory and its Application to the Position of Rolling Mill Control System

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 230-233页

作者： Jie Dong Chaonan Tong Kaixiang peng(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 controller designed according to classical or modern control theory will not satisfy the performance requirements when the controlled object in industrial field can not be described by exact mathematical model or the disturbance of the controlled system. In order to make the controlled system stable and having good performance, H∞ control theory was put forward to solve this practical problem. Taking the position of a rolling mill as the controlled object, it was rectified by optimal engineering way. Then, three different plans were put forward according to Bang-Bang control, LQ control and H∞ control, respectively. The result of the simulation shows that the controller designed according to H∞ method whose robust performance and ability to restrain colors disturbance is satisfactory.

关键词： position control H~∞ control LQ control Bang-Bang controll

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

Sintering Mechanism of Stainless Steel in Powder Injection Molding

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 51-54页

作者： Chengchang Jia Shimin Fan Ying peng Xiaojie Zhao Xiaosen lu Material science and Engineering School, university of science and technology beijing, beijing 100083, china beijing Tungsten and Molybdenum Factory, beijing 102206, china beijing Hard Me Material science and Engineering School University of Science and Technology Beijing Beijing 100083 China beijing Tungsten and Molybdenum Factory Beijing 102206 China beijing Hard Metal Factory Beijing 100055 China

Stainless steel samples were made by Powder injection Molding (PIM) process with-400 mesh powder in order to investigate the sintering mechanism in this system and develop the PIM of stainless steels. The process included mixing, injection molding, debin- ding and sintering. Neck growth model was used to analyze the sintering mechanism. The results show that lattice (volume) diffusion is the main mechanism in the sintering process, the products with higher density (>95%) and properties are obtained. At lower temperatures, grain boundary diffusion may play a role in the sintering densification.

关键词： sintering mechanism powder injection molding stainless steel, volume diffusion

Micro-alloying of yttrium in Zr-based bulk metallic glasses

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Progress in Natural science:Materials International 2011年第1期21卷 46-52页

作者： Wei-jie peng,Yong ZHANG State Key Laboratory for Advanced Metals and Materials, university of science and technology beijing,beijing 100083,china university of science and technology beijing

The effect of yttrium addition on the glass-forming ability(GFA) and mechanical properties of the Zr-based (Zr0.525Al0.1Ti0.05Cu0.179Ni0.146)100-xYxand(Zr0.55Al0.15Ni0.1Cu0.2)100-xYx(x=0,0.2,0.4 0.6,1,2) alloys was ***-alloying of 0.6%yttrium enhances the room temperature ductility as well as the GFA of the Zr-based *** mechanism of enhancing the GFA and room temperature ductility was *** is indicated that proper yttrium addition stabilizes the undercooled liquid by means of forming lots of ordered clusters,thus improving the GFA and the room temperature ductility.

关键词： micro-alloying glass-forming ability Zr-based alloys yttrium

Study on Microstructure and Property of H13 Die Steel with Nitrogen

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稀有金属材料与工程 2011年第S3期40卷 234-236页

作者： Chen Yulai, Liu Biao, Zhao peng, Tang Di, Li Jingyuan university of science and technology beijing, beijing 100083,china Univ Sci & Technol Beijing 100083 Peoples R China

Composition segregation and microstructure nonuniform of H13 steel have been obviously improved though adding nitrogen element. The microstructure and property of H13 steel with nitrogen contents of 0.021% and 0.085% are studied under various quenching and tempering states. Dual quenching that is quenching between 1000-1010 ℃ twice is employed in order to increase the tensile strength and hardness of coupons. The temperature and time are explored for improving the toughness under optimal quenching treatment. For extrusion die steel, the tensile strength can reach a satisfactory level and impact toughness are met the requirements of NADCA at the temperature.

关键词： H13 steel nitrogen chemical composition mechanical property

Irradiation Damage of Oxide Dispersion Strengthened Ferritic Steel after Recrystallization

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International Journal of Minerals,Metallurgy and Materials 1998年第3期12卷 160-164页

作者： Benfu Hu Shunmi peng H Takahashi(Material science and Engineering School, university of science and technology beijing, beijing 100083, china)(Faculty of Engineering, Hokkado university, Sapporo 060, Japan) Material science and Engineering School University of Science and Technology Beijing Beijing 100083 China Faculty of Engineering Hokkado University Sapporo 060 Japan

The evolution of secondary defects and the characteristics of the void swelling of electrons irradiated Oxide Dispersion Strengthened Ferritic Steels (ODS steels) after recrystallization were studied. It was found that recrystallization increases the void swelling of ODS steel as compared with solution and injected He+ + D+ *** are two size ranges of voids formed in recrystallized ODS steel during irradiation, and bubbles can be preferential sites for the void formation. Polycrystal with low density of defects is formed, and sites where point defects disappear by irradiation decrease. This is the main reason for the increase of void swelling of ODS steel after recrystallization.

关键词： ODS steel recrystallization, electron irradiation

Influence of sample surface condition on nano indentation experiment

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Rare Metals 2002年第2期21卷 131-132页

作者： WANG Yanli, LIN Zhi, LIN Junpin, peng Jihua, and CHEN GuoliangState Key laboratory for Advanced Metals and Materials, university of science and technology beijing, beijing 100083, china university of science and technology beijing State Key Laboratory for Advanced Metals and Materials 北京 100083

The microhardness and elastic modules of the materials weremeasured using the Nano Indenter II, which is a new measuring systemfor the mechanical properties of materials on nano-scale. It candetermine themicrohardness, elastic modules and other mechanicalproperties of materials through measuring applied load and depthunder indenter tip. The results indicated that surface condition ofsample such as the surface roughness affects the experimental preci-sion.

关键词： microhardness elastic modules Nano Indenter