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Effect of Reinforcement Speciality on Average Fracture Spacing of Reinforced Concrete Specimen

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Effect of Reinforcement Speciality on Average Fracture Spaci...

Effect of Pre-treatment on the Bi-2223/Ag Tapes Fabricated with Different Powders

第五届国际材料与热加工物理模拟及数值模拟学术会议

作者： Juanxia ZHANG 1 a Chun’an TANG2 b Xianzhang GUO3 c Xiuyan ZHOU1 d Shengguang ZHUO1 a Yandong PENG1 a 1northeastern university at qinhuangdao qinhuangdao P.R.China 066004) 2Department of Hydraulic and Civil Engineering of Dalian university of Technology Dalian P.R.China 116024) 3 School of Resource and Civil Engineering of northeastern university Shenyang P.R.China 110004)

A numerical test code named RFPA （Realistic Failure Process Analysis） was used to investigate the crack distribution rule of the reinforced concrete specimen under axial tension. The results indicate that the periodically distributed fracture spacing phenomenon exists in the failure process of the reinforced concrete structure and the effect of reinforcement characteristic on the mechanical behavior and average crack spacing of reinforced concrete specimen were also studied with five samples with different elastic modulus value of reinforcement. The elastic modulus value of reinforcement is considered to be an important factor not only to significantly influence on the average crack spacing but also to control the ultimate strain of the specimen, in addition, the average crack spacing is increased and the ultimate strain of the specimen is also increased with the decrease of the elastic modulus value of the reinforcement.

关键词： 3D, Numerical test Reinforcement concrete Crack distribution

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稀有金属材料与工程 2011年第S3期40卷 325-328页

作者： Li Mingya1, Chen Xingpin2, Ye Chengli1, Yu Liang1, Zhu Xu1 1 northeastern university at qinhuangdao, qinhuangdao 066004, China 2 Chongqing university, Chongqing 400044, China NE Univ qinhuangdao Dept Mat Sci & Engn Qinhuangdao 066004 Peoples R China Chongqing Univ Chongqing 400044 Peoples R China

Samples of Bi-2223/Ag tapes fabricated with powders contained different lead oxide compounds were annealed at a temperature lower than the formation temperature of Bi-2223 phase before traditional heat treatment, which was called pretreatment. In pre-treatment stage, samples were heat treated at 780 ℃ in 8.5% O2, and the dwelling time is different. Experimental results show that pre-treatment had different influence on the formation and size of the Bi-2223 grains for tapes fabricated with powders contained different lead oxide compounds. For tapes contained both Ca2PbO4 and the 3321 phase, the decomposition of the 3321 phase enhanced the growth of Bi-2212 grains during pre-treatment process, which promoted the formation of Bi-2223 phase and enhanced the superconducting properties of Bi-2223/Ag tapes.

关键词： pre-treatment Bi-2223/Ag tapes lead oxide compounds critical current

Unitary cyclic ESPRIT-like direction finding

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Science China(Information Sciences) 2010年第10期53卷 2087-2096页

作者： LIU ZhiGang & WANG JinKuan Department of Electronic Information, northeastern university, qinhuangdao 066004, China 1. Department of Electronic Information Northeastern University Qinhuangdao 066004 China

A unitary formulation of cyclic ESPRIT algorithm, with uniform linear array (ULA) configuration, is proposed by constructing the forward backward cyclic autocorrelation matrix by Hermitian mapping. This approach not only substantially reduces the computational complexity via real-valued decomposition, but also outperforms the forward backward spatial smoothing algorithm for uncorrelated or correlated sources. In addition, this method allows to select desired signals and to ignore interferences because of its signal-selective property. The performance analysis shows that for uncorrelated or correlated sources, the Hermitian mapping approach has a lower RMSE and a higher output SNR than the FBSS method. Finally, simulation results show the effectiveness of the proposed methods.

关键词： array signal processing cyclostationary signals direction of arrival cyclic ESPRIT unitary ESPRIT

Multi-channel neural mass modelling and analyzing

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Science China(Information Sciences) 2011年第6期54卷 1283-1292页

作者： CUI Dong 1 , LI XiaoLi 2 , JI XueQing 3 & LIU LanXiang 3 1 Institute of Information Science and Engineering, Yanshan university, qinhuangdao 066004, China 2 Institute of Electrical Engineering, Yanshan university, qinhuangdao 066004, China 3 The No.1 Hospital of qinhuangdao, qinhuangdao 066000, China 1. Institute of Information Science and Engineering Yanshan University Qinhuangdao 066004 China2. Institute of Electrical Engineering Yanshan University Qinhuangdao 066004 China3. The No.1 Hospital of Qinhuangdao Qinhuangdao 066000 China

Multi-channel neural signals generated by a computational model can help understand the mechanism of EEG rhythms, analyze brain functional connectivity and evaluate neural signal processing methods. In this study, a two-kinetics lumped-parameter neural mass model is extended to a multi-kinetics and multi-channel coupled model. This new model can effectively simulate the coupled dynamics activities between different areas in the brain. The simulation results show that the proposed model can generate neural signals with various frequency bands, from delta wave (1-4 Hz) to gamma wave (30-70 Hz), and the dynamics of the simulated neural signals is more complicated. The simulation analysis can also reveal the relationship between the coupled neural networks and the rhythm of neural populations, and the simulated neural signals can present the bi-modal and uni-modal phenomenon in the frequency domain when the coupling strength of models increases. Finally, analysis of an epileptic EEG signal from a rat demonstrates that the coupling among the neural populations can induce a large-scale seizure.

关键词： multi-channel neural mass model coupling spectrum synchronization epilepsy

First-principles calculations of electronic and magnetic properties of CeN:The LDA +U method

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Chinese Physics B 2013年第10期22卷 460-462页

作者：郝爱民白静 School of Resources and Materials Northeastern University at Qinhuangdao

Electronic and magnetic properties of CeN are investigated using first-principles calculations based on density func- tional theory （DFT） with the LDA ＋ U method. Our results show that CeN is a half-metal. The majority-spin electron band structure has metallic intersections, whereas the minority-spin electron band structure has a semiconducting gap straddling the Fermi level. A small indirect energy gap occurs between X and W. The calculated magnetic moment is 0.99 μb per unit cell.

关键词： first-principles calculations strongly correlated system electronic structure magnetic properties

Solution of a hollow thick-wall cylinder subject to quadric function pressures and its limit when l→∞

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Science China(Technological Sciences) 2004年第2期47卷 229-236页

作者： LIU Zhubai1,SHAN Rui2,LIU Wen2 & NI Liyong1 1.College of Mechanical Engineering,Yanshan university,qinhuangdao 066004,China 2.College of Science,Yanshan university,qinhuangdao 066004,China 1. College of Mechanical Engineering Yanshan University 066004 Qinhuangdao China 2. College of Science Yanshan University 066004 Qinhuangdao China

The problem of a hollow thick-wall cylinder subject to quadric function pressures is solved with a new stress function, thus laying the basis for solving the spatial symmetric deformation of a hollow cylinder subject ... 详细信息

关键词： quadric function pressure, analytic solution, stress function, hollow cylinder.

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 213001, China 2 northeastern university, Shenyang 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

Surface Modification of NiW Alloy Substrates

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稀有金属材料与工程 2011年第S3期40卷 380-382页

作者： Wang Xue1, 2, Li Chengshan2, Yu Zeming2, Zheng Huiling2, Ji Yongbin2, Chen Zewen 1, 2, Fan Zhanguo 1 1northeastern university, Shenyang 110004, China 2Northwest Institute for Non-ferrous Metal Research, Xi’an 710016, China NW Inst Nonferrous Met Res Superconducting Mat Res Ctr Xian 710016 Peoples R China northeastern Univ Shenyang 110004 Peoples R China

We have studied the adsorption of elemental S on the surfaces of NiW alloy substrates where elementary sulfur was used as sulfur source. Compared with those previous investigations which used H2S as the sulfur source and operated in an ultra-high vacuum chamber, we used elemental sulfur as the sulfur source which does not need an ultra-high vacuum chamber but Ar-H protection atmosphere in the process of sulfuration. After sulfuration, epitaxial LZO buffer layers were deposited on these substrates directly. The samples were investigated by means of AFM, XPS, SEM and XRD in this study. The results show that after sulfuration, S forms a c (2×2) structure at a coverage of 0.5 ML, in agreement with previous results, representing the effectiveness of elemental sulfur during the sulfuration process. The c (2×2)-S superstructure on the surface of the NiW substrates has optimized the La2Zr2O7(LZO) buffer layer texture.

关键词： NiW substrates sulfuration c (2×2) structure buffer layer

Partial Inverse Grain Size Dependence of Strength in High Mn Steels Microalloyed With Nb

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Journal of Iron and Steel Research International 2012年第9期19卷 68-72页

作者： DING Hua 1 , 2 , LI Hua-ying 1 , DING Hao 1 , QIU Chun-lin 2 , TANG Zheng-you 1 ( 1.School of Materials and Metallurgy , northeastern university , Shenyang 110819 , Liaoning , China 2.State Key Lab of Rolling and Automation , northeastern university , Shenyang 110819 , Liaoning , China ) [a] School of Materials and Metallurgy Northeastern University Shenyang 110819 Liaoning China [b] State Key Lab of Rolling and Automation Northeastern University Shenyang 110819 Liaoning China

Two steels without and with Nb addition were chosen to investigate the effects of Nb on the microstructures and the mechanical properties of Fe-Mn-Al-Si *** results revealed that Nb refined the grains markedly and both TRIP and TWIP effects occurred during deformation *** Nb containing steel possesses higher yield strength and much lower tensile strength , the latter being explained by the suppression of TRIP effect due to the increase of stacking fault *** indicates grain refining is secondary for strengthening of steels when TRIP or TWIP effect exists during the deformation of low carbon and high Mn steels.

关键词： grain size strength high Mn steel Nb