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science china(Technological sciences) 2005年第5期48卷 510-520页

作者： SU Juanhua1,2. LIU Ping2. DONG Qiming2.& LI Hejun1 1. college of materials {2. and engineering, Northwestern Polytechnical university, Xi’an 710072. china 2. college of materials {2. and engineering, Henan university of {2. and Technology, Luoyang 471003, china college of materials {2. and engineering Northwestern Polytechnical University Xi’an China college of materials {2. and engineering Henan University of Science and Technology Luoyang China

The thermomechanical treatment process is effective in enhancing the properties of the lead frame copper alloy. In this study, an optimal pattern of the thermomechanical processes for Cu-Cr-Zr was investegated using an intelligent control technique consisting of neural networks and genetic algorithms. The input parameters of the artificial neural network (ANN) are the reduction ratio of cold rolling, aging temperature and aging time. The outputs of the ANN model are the two most important properties of hardness and conductivity. Based on the successfully trained ANN model, genetic algorithms (GA) are used to optimize the input parameters of the model and select perfect combinations of thermomechanical processing parameters and properties. The good generalization performance and optimized results of the integrated model are achieved.

关键词： Cu-Cr-Zr alloy, thermomechanical processing optimization, artificial neural network, genetic algorithms.

Dynamic damage and stress-strain relations of ultra-high performance cementitious composites subjected to repeated impact

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science china(Technological sciences) 2010年第6期53卷 1520-1525页

作者： LAI JianZhong1 & SUN Wei2.1 Department of materials science and {2.,Nanjing university of science and Technology,Nanjing 2.0094,china 2.college of materials science and engineering,southeast university,Nanjing 2.1189,china Department of materials science and {2. Nanjing University of Science and Technology Nanjing China college of materials {2. and engineering Southeast University Nanjing China

Ultra-high performance cementitious composites (UHPCC) were prepared by replacing 60% of cement with ultra-fine industrial waste *** dynamic damage and compressive stress-strain relations of UHPCC were studied using split Hopkinson pressure bar (SHPB).The damage of UHPCC subjected to repeated impact was measured by the ultrasonic pulse velocity *** show that the dynamic damage of UHPCC increases linearly with impact times and the abilities of repeated impact resistance of UHPCC are improved with increasing fiber volume *** stress waves on impact were recorded and the average stress,strain and strain rate of UHPCC were calculated based on the wave propagation *** effects of strain rate,fibers volume fraction and impact times on the stress-strain relations of UHPCC were *** show that the peak stress and elastic modulus decrease while the strain rate and peak strain increase gradually with increasing impact times.

关键词： ultra-high performance cementitious composites (UHPCC) split Hopkinson pressure bar (SHPB) repeated impact damage stress-strain

Dynamic Mechanical Behaviour of Ultra-high Performance Fiber Reinforced Concretes

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Journal of Wuhan university of Technology(materials {2.) 2008年第6期23卷 938-945页

作者：赖建中 Department of materials science & {2. Nanjing University of Science & Technology

Ultra-high performance fiber reinforced concretes （UHPFRC） were prepared by replacing 60% of cement with ultra-fine industrial waste powder. The dynamic mechanical behaviour of UHPFRC with different fiber volume fraction was researched on repeated compressive impact in four kinds of impact modes through split Hopkinson pressure bar （SHPB）. The experimental results show that the peak stress and elastic modulus decrease and the strain rate and peak strain increase gradually with the increasing of impact times. The initial material damage increases and the peak stress of the specimen decreases from the second impact with the increasing of the initial incident wave. Standard strength on repeated impact is defined to compare the ability of resistance against repeated impact among different materials. The rate of reduction of standard strength is decreased by fiber reinforcement under repeated impact. The material damage is reduced and the ability of repeated impact resistance of UHPFRC is improved with the increasing of fiber volume fraction.

关键词： ultra-high performance fiber reinforced concretes split Hopkinson pressurebar dynamic repeated impact

Internal relative humidity and creep of concrete with modified admixtures

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Progress in Natural science:materials International 2011年第5期21卷 426-432页

作者： Zhi-hai HE~(1,2.,Chun-xiang QIAN~(1,2. 1.college of materials {2. and engineering,southeast university,Nanjing 2.1189,china 2.Jiangsu Key Lab of Construction materials,Nanjing 2.1189,china college of materials {2. and engineering Southeast University Nanjing 211189 China Jiangsu Key Lab of Construction materials Nanjing 211189 China

The creep characteristics and internal relative humidity(IRH) of concrete with shrinkage reducing admixtures(SRA),poly vinyl alcohol fiber(PVAF) and a mixture of fly ash and slag(MFS) were investigated by the self-made loading *** pore structure was tested,and the relationship of creep and IRH of concrete was *** results indicate that MFS and SRA reduce the total creep and delay the change of ***,the effect of PVAF is contrary,relative to MFS and *** total creep depends largely on drying *** basic creep of concrete is similar,which is significantly influenced by volume fraction of pores whose diameter is between 3.5 nm and 50 nm to the total pore(VP),and IRH of concrete is connected with *** is easy to obtain a good linear relationship predicting the creep of concrete according to the change of IRH.

关键词： modified admixture internal relative humidity total creep drying creep basic creep porosity

Two-and Three-Dimensional Chloride Ingress into Fly Ash Concrete

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Journal of Wuhan university of Technology(materials {2.) 2011年第5期26卷 978-982页

作者：张云升 Jiangsu Key Laboratory for Construction materials Southeast University college of materials {2. and engineering Southeast University

2.,3D chloride ion concentration at the edge and corner zones were systematically investigated for fly ash concretes made with different cement replacement percentage by fly ash （0%,10%,2.%,40%,60%）,water to binder ratios （0.3,0.35,0.4）,and curing ages （2. d,90 d）.An interaction effect caused by 2. and 3D diffusion could obviously be observed through the comparison with 1D testing *** order to quantify the interaction effect,2. and 3D diffusion interaction coefficients was proposed in this ***,the changes of 2. and 3D interaction coefficients with the change in the free chloride ion concentration were *** above research provide an insight into chloride ion attack on the edge and corner reinforcing bars of concrete structures in the field of civil engineering.

关键词： fly ash concrete chlorides two and three dimension ingress

Comparison of the fracture process of the rubberized concrete and plain concrete under bending load

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science china(Technological sciences) 2010年第6期53卷 1526-1533页

作者： ZHANG YaMei1,WANG Chao2.LU Yi1 & MA AiBin2.1 Jiangsu Key Laboratory of Construction materials,southeast university,Nanjing {2.,china 2.college of materials science and engineering,Hohai university,Nanjing 2.0098,china Jiangsu Key Laboratory of Construction materials Southeast University Nanjing China college of materials {2. and engineering Hohai University Nanjing China

Acoustic emission (AE) technique is employed to investigate the damage process of the notched plain concrete and rubberized concrete specimens under 3-point bending *** signals in the fracture process of notched specimens are illustrated by analyzing the distribution of amplitude and hit rate of AE *** signals in the rubberized concrete have lower activity and amplitude than in the plain *** AE location analysis,it is found that the high energy events mainly are distributed near the notch *** to AE energy,the fracture process zone (FPZ) is *** comparing the FPZ of both concretes,it is found that the incorporation of rubber particles in concrete can greatly alleviate the damage process of concrete specimens and the damage zone in the rubberized concrete is much smaller than in the plain *** moment tensor is also used to analyze the type of cracks and it is found that tensile cracks dominate the early period of loading,while shear cracks become dominant with propagation of cracks in late load period.

关键词： concrete rubberized concrete acoustic emission damage moment tensor

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

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science china(Technological sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2. LIU GuoQuan2. LI ZhiLin3, FENG ChengMing1 1 Mechanical and Electronic engineering college, Shandong Agricultural {2., Tai’an 2.1018, china 2.college of materials science and engineering, {2. of science and Technology, Beijing 100083, china 3 college of Material science and engineering, Beijing {2. of Chemical Technology, Beijing 10002., china Mechanical and Electronic engineering college Shandong Agricultural University Tai’an China college of materials {2. and engineering University of Science and Technology Beijing China college of Material science and {2. Beijing University of Chemical Technology Beijing China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

Magnetron sputtering synthesis of large area well-ordered boron nanowire arrays

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science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 403-415页

作者： CAO Limin1,2. ZHANG Ze2.& WANG Wenkui1,2.1. Key Laboratory of Metastable materials science and Technology and {2. of materials science and engineering, Yanshan university, Qinhuangdao 066004, china 2. Institute of Physics, Chinese Academy of sciences, Beijing 100080, china Key Laboratory of Metastable materials science and Technology and {2. of materials science and engineering Yanshan University Qinhuangdao China Institute of Physics Chinese Academy of Sciences Beijing China

One-dimensionally nanostructured materials, such as nanowires and nanotubes, are the smallest dimensional structures for efficient transport of electrons and excitons, and are therefore critical building blocks for nanoscale electronic and mechanical devices. In this paper, boron nanowires with uniform diameters from 2. to 80 nm were synthesized by radio-frequency magnetron sputtering of pure boron powder and B2.3 powder mixtures in argon atmosphere. The boron nanowires produced stand vertically on the substrate surface to form well-ordered arrays over large areas with self- organized arrangements without involvement of any template and patterned catalyst. The high-density boron nanowires are parallel to each other and well distributed, forming highly ordered and uniform arrays. A more interesting and unique feature of the boron nanowires is that most of their tips are flat rather than hemispherical in morphologies. Detailed studies on its structure and composition indicate that boron nanowires are amorphous. Boron nanowire appears as a new member in the family of one-dimensional nanostructures. Considering the unique properties of boron-rich solids and other nanostructures, it is reasonable to expect that the boron nanowires will display some exceptional and interesting properties. A vapor-cluster-solid (VCS) mechanism was proposed to explain the growth of boron nanowires based on our experimental observations.

关键词： boron nanowires, magnetron sputtering, arrays, self-assembly.

Integrated intelligent control analysis on semi-active structures by using magnetorheological dampers

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science china(Technological sciences) 2008年第12期51卷 2270-2284页

作者： XU ZhaoDong1 & GUO YingQing2.1Civil engineering college, {2., Nanjing 2.0096, china 2.Automation college, {2., Nanjing 2.0096, china Civil engineering college Southeast University Nanjing China Automation college Southeast University Nanjing China

The control strategy is very important for semiactive control or active control systems. An integrated intelligent control strategy for building structures incorpo rated with magnetorheological (MR) dampers subjected to earthquake excitation is proposed. In this strategy, the time-delay problem is solved by a neural network and the control currents of the MR dampers are determined quickly by a fuzzy controller. Through a numerical example of a three-storey structure with one MR damper installed in the first floor, the seismic responses of the uncontrolled, the intelligently controlled, the passiveon controlled, and the passive-off controlled structures under different earthquake excitations are analyzed. Based on the numerical results, it can be found that the time domain and the frequency domain responses are reduced effectively when the MR damper is added in the structure, and the integrated intelligent control strategy has a better earthquake mitigation effect.

关键词： magnetorheological damper semi-active control intelligent

Microstructure and formation mechanism of twins of laths of austenite with high nitrogen

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science china(Technological sciences) 2007年第6期50卷 755-764页

作者： WU CuiLan1,2.& LUO ChengPing2.1 Center for High Resolution Electron Microscopy, college of materials {2. and engineering, Hunan university, Changsha 410082. china 2.college of Mechanical engineering, South china university of Technology, Guangzhou 510641, china Center for High Resolution Electron Microscopy College of Materials Science and Engineering Hunan University Changsha China college of Mechanical engineering South China University of Technology Guangzhou China

The microstructure of composite diffusion layer of the nitrided and chromized 0.2. carbon steel is investigated using TEM and EDS. It is found that laths of austenite with high nitrogen (γ N) precipitate from α-ferrite matrix in the deeper zone of the diffusion layer. These γ N laths are all twins, with their {111} twinning planes parallel to the lath axis, thus forming a characteristic "back-to-back" morphology. There are two types of γN lath. The first is a genuinely {111} twin, and γ N and α keep the accurate K-S relationship, and each γ N and α form a sharp and smooth γ N/α inter- face of {335}γN//{341}α, namely habit plane {335}fcc. The second is a pseudo-twin, with micro-twins {111} or faults formed within the two twin components. Localized lattice deformation (relaxation) seems to have occurred at the interfaces of the second type of γ N due to the formation of micro-twins or faults within the twin components. These micro-twins or faults make the orientation relationship (OR) between each of the γN and the α-matrix deviate from the accurate K-S OR, and the OR between two γ N twin components deviate from the genuine {111} twin relation- ship. In addition, the γ N/α interface of the second type of γ N is not as sharp or smooth as that of the first one.

关键词： austenite containing nitrogen, twins, steel 2., nitriding, composite chromizing