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Development in Conducting Bus of RE-Al Alloys

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Rare Metals 2001年第2期20卷 107-111页

作者： Jizhou Wang, Jingxia Li, Lu Shi, Zhenzhong Tai (Material and Metallurgical College, northeastern university, Shopna 110015, china shenyang ASTRON Mining Ltd. Corp., shenyang 110003. china) NE Univ Mat & Met Coll Shenyang 110015 Peoples R China shenyang ASTRON Min Ltd Corp Shenyang 110003 Peoples R China

Four kinds of deformed aluminum alloys were tested. One kind of RE-Al-Mg-Si alloy, which possessed high conductivity and strength, was the first priority by contrast test. The large specification bus of conducting aluminum alloys was made by thermomechanical process during the industrial experiment. The properties of the bus are as follows: the tensile strength sigma (b) is 23. MPa, the conductivity (v.s. IACS) is 54.3., and the current-carrying capacity is beyond 3.1 kA during working process. This kind of RE-Al alloy bus has been applied to several electrical transmitting and transforming work.

关键词： rare earth element aluminum alloy conducting bus thermomechanical process

A New Admissibility Condition of Discrete-time Singular Systems with Time-varying Delays

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International Journal of Automation and computing 2012年第5期9卷 480-486页

作者： Yong-Yun Shao 1,3.Xiao-Dong Liu 1,2 Xin Sun 3.Zhan Su 4 1 Transportation Management College, Dalian Maritime university, Dalian 116026,{3. 2 Department of Mathematics, Dalian Maritime university, Dalian 116026,{3. 3.Department of Computer and Mathematics Teaching, shenyang Normal university, shenyang 11003.,{3. 4 Institute of Systems Science, northeastern university, shenyang 110004,{3. 1. Transportation Management College Dalian Maritime University Dalian 116026 China 3. Department of Computer and Mathematics Teaching Shenyang Normal University Shenyang 110034 China 2. Department of Mathematics Dalian Maritime University Dalian 116026 China 4. Institute of Systems Science Northeastern University Shenyang 110004 China

This paper gives a novel delay-dependent admissibility condition of discrete-time singular systems with time-varying delays. For convenience, the time-varying delay is assumed to be the sum of delay lower bound and the integral multiples of a constant delay. Specially, if the constant delay is of unit length, the delay is an interval-like time-varying delay. The proposed admissibility condition is presented and expressed in terms of linear matrix inequality (LMI) by Lyapunov approach. Generally, the uncertainty of time-varying delay would lead to conservatism. In this paper, this critical issue is tackled by accurately estimating the time-varying delay. Consequently, the proposed admissibility condition is less conservative than the existing results, which is demonstrated by a numerical example.

关键词： Singular systems discrete-time delay-dependent admissibility time-varying delay

Effect of Cu on the Spinodal Decomposition of AlZn Alloy with Symmetrical Composition

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Journal of Materials Science & Technology 2005年第6期21卷 836-840页

作者： Shiming HAO+, Yuping REN, Hongxiao LI, Dapeng WANG and Gang ZHAOCollege of Materials and Metallurgy, northeastern university, shenyang 110004, china College of Materials and Metallurgy Northeastern University Shenyang 110004 China

The effect of Cu addition on the spinodal decomposition of the Al-Zn alloy with symmetrical compositions has been investigated by X-ray diffraction analysis. It is found that the single fcc phase can be obtained in the AlZn alloy with the addition of 2 at. pct Cu after solution treatment at 400℃ and water quenching to room temperature. The modulation structure occurs in two types of alloys aged at room temperature for 3. min. The spinodal process remarkably slows down above or at the three phase equilibrium temperature, particularly at room temperature due to the addition of 2 at. pct Cu. The spinodal time increases by 20 times when aging at 3.0℃ and by more than 3. times when aging at room temperature.

关键词： Al-Zn(-Cu) alloy Spinodal decomposition Lattice parameter X-ray diffraction

Effects of Pre-Ageing Treatment on Subsequent Artificial Ageing Characteristics of an Al-1.01Mg-0.68Si-1.78Cu Alloy

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Journal of Materials Science & Technology 2010年第2期26卷 141-145页

作者： Lizi He , Haitao Zhang and Jianzhong Cui Key Lab of Electromagnetic Processing of Materials, Ministry of Education, northeastern university, shenyang 110004, china [a] Key Lab of Electromagnetic Processing of Materials Ministry of Education northeastern university shenyang 110004 china

The influences of pre-ageing temperature and natural ageing time on subsequent artificial age hardening behavior and precipitation sequence of new type Al-1.01Mg-0.O8Si-l.78Cu alloy were investigated by hardness test, differential scanning calorimetry （DSC） test and transmission electronic microscopy （TEM） observations. When pre-ageing temperature is 20℃ （natural ageing）, the peak hardness of subsequent artificial aged alloy is lower than that of T6 treated alloy （negative effect）, while a positive effect appears when pre-ageing temperature is above 80℃. The size of needlelike /3.precipitate in subsequent artificial aged alloy is much coarser when pre-ageing temperature is 20℃, which causes a decrease in peak-hardness. The positive effect occurs again when natural ageing time is longer than 3.weeks. There are seven exothermic peaks in DSC curve of as-quenched alloy, while the number and height of exothermic peak decrease with increasing pre-ageing temperature and natural ageing time.

关键词： Al-Mg-Si-Cu alloy Pre-ageing treatment Age hardening Differential scanning calorimetry (DSC) curve

Generating function approach to reliability analysis of structural systems

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Science china(Technological Sciences) 2009年第10期52卷 2849-2858页

作者： ZHOU JinYu1 & XIE LiYang2 1 Jiangsu Teacher’s university of Technology, Changzhou 213.01, china 2{3., {3. 110004, china 1. Jiangsu Teacher’s university of Technology Changzhou 213001 China 2. northeastern university Shenyang 110004 China

The generating function approach is an important tool for performance assessment in multi-state systems. Aiming at strength reliability analysis of structural systems, generating function approach is introduced and developed. Static reliability models of statically determinate, indeterminate systems and fatigue reliability models are built by constructing special generating functions, which are used to describe probability distributions of strength (resistance), stress (load) and fatigue life, by defining composite operators of generating functions and performance structure functions thereof. When composition operators are executed, computational costs can be reduced by a big margin by means of collecting like terms. The results of theoretical analysis and numerical simulation show that the generating function approach can be widely used for probability modeling of large complex systems with hierarchical structures due to the unified form, compact expression, computer program realizability and high universality. Because the new method considers twin loads giving rise to component failure dependency, it can provide a theoretical reference and act as a powerful tool for static, dynamic reliability analysis in civil engineering structures and mechanical equipment systems with multi-mode damage coupling.

关键词： structure reliability generating function static strength failure fatigue failure failure dependence

Equilibrium Phase Constituents and Discontinuous Precipitation Behavior of Al-Zn-Cu Alloy with Symmetrical Composition

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Journal of Materials Science & Technology 2003年第5期19卷 419-421页

作者： Shiming HAO, Yuping REN, Hua DING, Dapeng WANG, Gang ZHAO and Hongxiao LISchool of Materials and Metallurgy, northeastern university, shenyang 110004, china Sch. of Mat. and Metall. Northeastern Univ. Shenyang 110004 China

Through microstructure observation and X-ray diffraction analysis, the equilibrium phase constituents of Al-Zn alloy that contains 2 at. pct Cu at room temperature have been determined as Al-based solid solution (α), Zn-based solid solution and AI4Cu3.n phase (T'-phase), which are different from a phase, Zn phase and CuZn4 phase originally believed. It is determined that the products of discontinuous precipitation transformation below 277℃ are not the equilibrium phase constituents, but the metastable phases made up of a phase, Zn phase and CuZn4 phase. The phase constituents after discontinuous precipitation of AIZn-2Cu alloy would transform to the ones in equilibrium status: Al-based solid solution (α) in fcc structure, Zn-based solid solution in hcp structure and AI4Cu3.n phase (T'-phase) ultimately through plastic deformation at room temperature and re-heating treatment below 277℃.

关键词： Al-Zn-Cu alloy Discontinuous precipitation Phase constituents Deformation

Effect of Cu on Discontinuous Precipitation of a Symmetrical AlZn Alloy

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Journal of Materials Science & Technology 2005年第2期21卷 215-218页

作者： Shiming HAO, Yuping REN, Dapeng WANG, Danyang DONG and ffongxiao LI College of Materials and Metallurgy, northeastern university, shenyang 110004, china College of Materials and Metallurgy Northeastern University Shenyang 110004 China

The effect of Cu additions on discontinuous precipitation of AlZn alloy were studied with optical microscopy, scanning electron microscopy and X-ray diffraction. It is found that the effect of addition of 2 at. pct Cu on cellular nucleation site is not remarkable, while the effect of aging temperature on cellular nucleation site of AlZn and AIZn-2Cu alloys is fairly obvious. The cell growth rate of discontinuous precipitation of AlZn alloy is remarkably accelerated with the addition of 2 at. pct Cu. The discontinuous precipitation microstructure of AlZn alloy is not apparently affected with the addition of 2 at. pct Cu and the cellular front is still fine microstructure of spinodal decomposition. The phase constituents consist of a fcc Al-rich phase, a hcp Zn-rich phase and a CuZn4 phase. The transformation rate of discontinuous precipitation of AlZn alloy is remarkably accelerated with the addition of 2 at. pct Cu.

关键词： Al-Zn(-Cu) alloy Spinodal decomposition Discontinuous precipitation Transformation rate

INFLUENCE OF CASTING FLOW DEVIATION ON FLUID FLOW IN CASTING BILLET MOLD

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Acta Metallurgica Sinica(English Letters) 1995年第3期8卷 226-230页

作者： ZHA NG Jiongming (Anshan Iron and Steel Research Institute,Anshan, Liaoning, china)HE Jicheng LI Baokuan (northeastern university, {{3., china) Anshan Iron and Steel Research Inst Anshan China

In this paper, the three dimensional flow field in the billet mold has been studied by simple numerical *** influence caused by teeming *** the mold center has been discussed.

关键词： continuos casting mold teeming.flow

COUPLING PROCESS FOR Ti AND Si BETWEEN TITANIA SLAGS AND Cu MELTS AT 1500 ℃

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中国有色金属学会会刊：英文版 1995年第2期5卷 34-38页

作者： Xue,Xiangxin Che,Yinchang (Department of Ferrous Metallurgy, northeastern university, shenyang 110006) northeastern Univ Shenyang China

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关键词： coupling reaction apparent mass transfer coefficient titania slag Cu melt