检索结果-南通市图书馆

Modulated Quasi-plane Tunneling Current

在线全文

学校读者我要写书评

暂无评论

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) Beijing 100080 P.O. Box 8730 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

Representations of Real and Complex Stability Radii of 2-Dimensional LinearSystems

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 1999年第4期13卷 299-301页

作者： Lequan Min1.2 Ning Song1(l Applied science School, University of science and technology’ beijing, beijing 100083, china2 china center of advanced science and technology, beijing 100080, china) Applied science School University of Science and Technology Beijing Beijing 100083 China china center of advanced science and technology Beijing 100080 China

Rigorous proofs are given for the representations of real and complex stability' radii of 2-dimensional linear systems. This representations can be used to analyze the robustness of a nominal 2-dimensional linear system under pelturbation of the system parameters, in particular testing the effect of numerical algorithms which are used to calculate the real stability radii of higher dimensional piecewise-linear systems.

关键词： linear systems robustness stability radii

Online application of automatic surface quality inspection system to finishing line of cold rolled strips

在线全文

学校读者我要写书评

暂无评论

Journal of University of science and technology beijing 2003年第4期10卷 38-41页

作者： Hao Sun, Ke Xu, and Jinwu XuNational Engineering Research center of advanced Rolling, University of science and technology beijing, beijing 100083, china Natl. Eng. Res. Ctr. of Adv. Rolling Univ. of Sci. and Technol. Beijing Beijing 100083 China

An automatic surface quality inspection system installed on a finishing lineof cold rolled strips is introduced. The system is able to detect surface defects on cold rolledstrips, such as scratches, coil breaks, rusts, roll imprints, and so on. Multiple CCD area scancameras were equipped to capture images of strip surface simultaneously. Defects were detectedthrough 'Dark-field illumination' which is generated by LED illuminators. Parallel computationtechnique and fast processing algorithms were developed for real-time data processing. Theapplication to the production line shows that the system is able to detect defects effectively.

关键词： surface inspection cold rolled strip finishing line CCD cameras imageprocessing

SUPERCONVERGENCES OF THE ADINI'S ELEMENT FORSECOND ORDER EQUATION

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 1999年第6期17卷 569-574页

作者： Ping Luo(Department of Computer science and technology, Qinghua University, beijing 100084,china)Qun Lin(Institute of Systems science, Academia Sinica, beijing, 100080, china) 清华大学计算机系北京 100084 中科院系统科学所北京 100080

n this papers the asymptotic error expansions of Adini's element for the secondorder imhomogeneous Neumann problem are given and the superconvergence estimations are obtained. Moreover, a numerical example to support ... 详细信息

关键词： Adini's element Superconvergence estimation Asymptotic expansion.

Distribution of Nb atom in the TiAl+Nb system

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2001年第1期20卷 5-12页

作者： Xiaodong Ni, Xidong Hui, Guoliang Chen (Applied science School, University of science and technology beijing, beijing 100083, china State Key Laboratory for advanced Metals and Materials, University of science and technology beijing, china) 北京科技大学新金属材料国家重点实验室北京 100083 北京科技大学新金属材料国家重点实验室北京

Based on MEAM (the modified embedded atom method) potential and an average atom model similar to B-W (Bragg-Williams) method, the distribution of Nb atoms in TiAl+Nb compounds with various composition was calculated. The calculation results showed that Nb atoms prefer to occupy the Ti sublattice of L10 structure for all compounds in question. With increasing atomic fraction of Nb and Al, Nb atoms exhibited a trend of ordered distribution on the Ti sublattice and result in a new L10 derivative superlattice structure.

关键词： Computer simulation Intermetallics Superlattices Ternary systems

Cleaning of Chromate Manufacture Process

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 132-134页

作者： Xing Zou Yi Zhang(Applied science School, University of science and technology beijing, beijing 100083, china)(Institute of Engineering Chemistry and Metallurgy, Chinese Academy of sciences, beijing 100080, china) Applied science School University of Science and Technology Beijing Beijing 100083 China Institute of Engineering Chemistry and Metallurgy Chinese Academy of Sciences Beijing 100080 China

Sodium chromate solubility is determined in the range of NaOH concentrations from 450 to 810 g/L andsolution temperatUres from 30 to 110℃. The optimized conditions to separate sodium chromate from NaOH inleached solution are resolved. It is first found the method to efficiently separate sbdium chromate from NaOH andsodium altuninate in crude sodium chromate. Bench-scale studies on the separating are performed. Finally, goodseparation results are achieved.

关键词： chromate separation clean process

MEAM Potential with Angular Dependence for TiAl

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2001年第1期20卷 13-17页

作者： Xiaodong Ni, Xitao Wang, Guoliang Chen (Physics Department, University of science and technology beijing, beijing 100083, china State Key Laboratory for advanced Metals and Materials, University of science and technology beijing, beijing 100083, china) 北京科技大学新金属材料国家重点实验室北京 100083 北京科技大学北京 100083

The modified embedded atom method (MEAM) is an empirical extension of the embedded atom method (EAM) that includes angular forces. By fitted to the lattice constants, the cohesive energy, the APE (anti-phase boundary) energy, and the vacancy formation energy of TiAl, an accurate MEAM potential is obtained for the TiAl system with L10 structure. The calculation results of the properties of TiAl are in good agreement with experiments and the results of first principle (F.P.) calculations.

关键词： embedded atom method TiAl alloy angular dependence potential intermetallics

Effect of Heating Rate Before Tempering on Reversed Austenite in Fe-9Ni-C Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2012年第9期19卷 73-78页

作者： ZHANG Kun , TANG Di , WU Hui-bin ( National Engineering Research center of advanced Rolling , University of science and technology beijing , beijing 100083 , china ) National Engineering Research center of advanced Rolling University of Science and Technology Beijing Beijing China

The alloy was reheated to 580℃ for tempering at rates of 2 , 5 , 10 , 20 , and 40℃ / s , respectively , after *** amount , distribution , and stability of reversed austenite were investigated by X-ray diffraction ( XRD ) and electron back scatter diffraction ( EBSD ) .The microstructure and cryogenic impact energy were studied by scanning electron microscope ( SEM ), transmission electron microscope ( TEM ) and Charpy V-notch ( CVN ) *** results showed that when the sample was heated at 10℃ / s , the volume fraction of reversed austenite exhibited maximum of 8% ; the reversed austenite was uniform along all kinds of boundaries ; the reversed austenite contained higher concentration of carbon which enabled it to be more *** cryogenic toughness of the alloy was greatly improved when heated at 10℃ / s , as the fracture surface observation showed that it mainly fractured in ductile rupture mode , which was consistent with the results of cryogenic impact energy.

关键词： 9Ni steel heating rate reversed austenite cryogenic toughness

Theorems for Testing Local Activity of CNN and Application to Cardiac Purkinje Equations

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2000年第2期14卷 139-146页

作者： Lequan Min(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 theorems for testing the local in one-port cellular neural/inear network (CNN) cells with four local state variables are presented. Using the theorems computes the bifurcation diagrams of the cardiac Purkinje fiber (CPE) equations Which describethe long-lasting action and pace-maker potentials of the Purkinje fiber of the heart. The computer simulation shows that periodic trajectories or convergent trajectories of the CPF Equations can be foun if the cormsponing cell Parameters are located in a positive domainbut nearby edge of chaos. In particular a heart with approximate normal frequency of heartbeat but non-normal electrocardiogram maysuddenly stop by slightly perturbing the parameters of the corresponding CPF Equations when the Paramders are located nearby the edge of chaos in the bifurcation diagrams. This research seems to interpret reasonbly the phenomena that patients with cardiac diseases might suddenly die without warning.

关键词： cellular neural network local activity cardiac Purkinje fiber heartbeat