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Investigation on Uniaxial Tensile Instability of USIBOR1500 Steel Sheets at Elevated Temperature

Chinese Journal of Mechanical Engineering 2010年第1期23卷 94-99页

作者： MIN junying LIN Jianping TIAN Haobin SUN Guohua XU Zhou College of Mechanical Engineering Tongii University Shanghai 201804 China College of Mechanical and Electrical Engineering Shanghai Second Polytechnic University Shanghai 201209 China

In the sheet forming process with stretch, diffuse instability and localized instability usually occur in the process one after another. The necking rate has a great impact on the instability process and the forming limits of the rate sensitive material, such as USIBOR1500 steel sheets at elevated temperature. The available reports about this steel mainly focus on hot uniaxial tensile, martensitic transformation and forming process, but there are few investigations on instability behavior and forming limits. Based on Inoue Kachiro＇s flow stress constitutive model at elevated temperature, combined with Swift＇s diffuse instability rule and Hill＇s localized instability nile, the relation is theoretically deduced between the diffuse necking rate along with the localized necking rate and the exponent of strain rate sensitivity together with the strain rate in the case of the USIBOR1500 steel sheets at elevated temperature. According to the time-temperature characteristics of the hot stamping process, tensile tests of the steel sheets were carried out on Gleeble3800, and the stress-strain curves were obtained at different temperatures and different strain rates. Then the values of the exponent of strain rate sensitivity and the hardening exponent were obtained through fitting the curves by least squares. The tests also helped to provide the distribution laws of the major strain of the specimens and the uniform strains as well as the necking width. The uniform strains obtained from the tests are matched well with the theoretical calculations.

关键词： USIBOR1500 uniaxial tensile instability uniform strain necking rate

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Joint frequency,2-D DOA,and polarization estimation using parallel factor analysis

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Science in China(Series F) 2009年第10期52卷 1891-1904页

作者： LIANG JunLi LIU Ding ZHANG junying School of Computer Science and Engineering Xi'an University of Technology Xi'an 710048 China School of Automation and Information Engineering Xi'an University of Technology Xi'an 710048 China School of Computer Xidian University Xi'an 710071 China

This paper proposes a new algorithm for joint frequency, two-dimensional （2-D） directions-of-arrival （DOA）, and polarization estimation using parallel factor （PARAFAC） analysis model and cumulant. The proposed algorithm designs a new array configuration, and extends the PARAFAC analysis model from the common data-domain and subspace-domain to the cumulant one, and forms three-way arrays by using the three cumulant matrices obtained from the properly chosen dipole outputs, and analyzes the uniqueness of low-rank decomposition of the three-way arrays, and then jointly estimates the source parameters via the low-rank decomposition of the constructed PARAFAC model. In comparison with the conventional methods, the proposed method alleviates the aperture loss, and avoids pairing parameter. Finally, the simulation results are presented to validate the performance of the proposed method.

关键词： array signal processing cumulant parallel factor analysis polarization sensitive array

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Enhanced Performance of Osteoblasts by Silicon Incorporated Porous TiO_2 Coating

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Journal of Materials Science & Technology 2012年第2期28卷 109-117页

作者： Quanming Wang Hongjie Hu Yuqing Qiao Zhengxiang Zheng junying Sun Orthopaedic Department The First Affiliated Hospital of Soochow University 188 Shizi Street Suzhou 215006 China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

Silicon （Si） incorporated porous TiO2 coating （Si-TiO2） prepared on titanium （Ti） by micro-arc oxidation （MAO） technique was demonstrated to be cytocompatible in previous studies. In view of the potential clinical applications, a detailed in vitro study of the biological activity of Si-Ti02 coating, in terms of osteoblast （MC3T3-EI cells） morphology, proliferation, differentiation and mineralization was performed. Immunofluo- rescent staining indicated that cells seeded on the Si-TiO2 coating showed improved adhesion with developing mature cytoskeletons, which contained numerous distinct and well-defined actin stress fibers in the cell mem- branes compared with those on the Ti02 coating and Ti plate. Results from proliferation assay showed that the proliferation rate of cells seeded on the Si-TiO2coating was significantly faster than that on the TiO2 coating and Ti plate. Furthermore, the analysis of osteogenic gene expression demonstrated that the Si-Ti02 coating stimulated the expression of osteoblast-related genes and promoted differentiation and mineralization of MC3T3-EI cells. In addition, the Si-TiO2 coating differentially regulated Wnt signaling pathway by up-regulating the expression of low-density lipoprotein （LDL） receptor-related protein 5 （LrpS）, and downregulating the expression of Dickkopf-1 （Dkkl）. All together, these results indicate that the investigated titanium with Si-TiO2 coating is biocompatible and a good candidate material used as implants.

关键词： Micro-arc oxidation Silicon TiO2 Osteoblast Gene expression

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Necking of Q&P Steel during Uniaxial Tensile Test with the Aid of DIC Technique

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Chinese Journal of Mechanical Engineering 2013年第3期26卷 448-453页

作者： DING Lei LIN Jianping MIN junying PANG Zheng YE You School of Mechanical Engineering Tongji University Body & Exterior Department Pan Asia Technical Automotive Center

A lot of research has been focused on the necking process during the plastic deformation of sheet metals, but the localized necking is rarely distinguished form diffused necking by experiments, due to the limit of measurement equipment and method. Quenching and Partitioning (Q&P) steel is a 3rd generation advanced high strength steel (AHSS). Its good combination of high strength and ductility ensures potential application in automobile industry. Uniaxial tensile tests of QP980 steel sheet at five strain rates are performed to investigate the necking process and the effect of strain rate on necking behavior of Q&P steel. Digital image correlation (DIC) method is applied during tensile tests, and evolutions of major strain, minor strain and normal strain distributions along gauge section of the tensile specimens are obtained. The diffused and localized necking strains are determined according to SWIFT necking theory and HILL necking theory respectively. The test results indicate that with the increasing of strain rate in the investigated range, the diffused necking strain decreases from 0.152 to 0.120 and localized necking strain decreases from 0.245 to 0.137. Meanwhile, the difference of the two strains decreases form 0.096 to 0.017. Thus it can be concluded that strain rate has an influence on both necking strains during the deformation of QP980 steel sheet. Diffused and localized necking strains are determined by uniaxial tensile tests with the aid of DIC technique and the effect of strain rate on necking strains is evaluated.

关键词： Q&P steel strain rate DIC SWIFT necking theory HILL necking theory

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Study of pre-processing model of coal-mine hoist wire-rope fatigue damage signal

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International Journal of Mining Science and Technology 2015年第6期25卷 1017-1021页

作者： Tian Jie Wang Hongyao Zhou junying Meng Guoying School of Mechanical Electronic and Information Engineering China University of Mining and Technology

In this paper, we propose a pre-processing method for the detection of wire-rope signals. This is necessary because of the lack of processing methods that are currently employed. First, we investigated the one-dimensional discrete morphological and wavelet transform. Then, we developed a pre-processing model that is based on the morphological wavelet-filtering algorithm. We then proposed a modified morphology filtering algorithm. We also designed an experiment platform for wire-rope *** levels of localized flaws(LFs) and damage were formed in the wire-rope specimen. We performed a series of experimental studies, and the results show that the proposed method can effectively filter the drift signal. The signal-to-noise ratio of the new filtering algorithm was over 26 d B. The signal-to-noise ratio of the existing method is less than 15 d B, and the noise-signal ratio of the new filtering algorithm has improved by 73%. Based on our results, the filtering effect of the proposed method is better than that of the present method. This study has great significance and practical value in engineering applications.

关键词： Coal-mineHoist wire ropeSignal processingFast morphological wavelet-filteringalgorithm

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Biological Activity and Antibacterial Property of Nano-structured TiO_2 Coating Incorporated with Cu Prepared by Micro-arc Oxidation

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Journal of Materials Science & Technology 2013年第3期29卷 237-244页

作者： Wei Zhu Zhenxiang Zhang Beibei Gu junying Sun Lixian Zhu Orthopedic Department The First Affiliated Hospital of Soochow University Orthopedic Department Orthopedic DepartmentThe Affiliated Taizhou People's Hospital of Nantong University

Micro-arc oxidized Cu-incorporated TiO2 coatings （Cu-TiO2） were prepared in the Ca, P, Cu-containing electrolyte to obtain an implant material with superior biological activity and antibacterial property. The surface topography, phase, and element composition of the TiO2 and Cu-TiO2 coatings were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and energy-dispersive X-ray spectrometry （EDS）, respectively. Staphylococcus aureus （S. aureus） was selected to evaluate the antibacterial property of the Cu-TiO2 coatings, whereas osteoblastic MG63 cells were cultured on the coatings to investigate the biological activity. The obtained results demonstrated that Cu element was successfully incorporated into the porous nano-structured TiO2 coatings, which did not alter apparently the surface topography and phase composition of the coatings as compared to the Cu-free TiO2 coatings. Moreover, the antibacterial studies suggested that the Cu-incorporated TiO2 coatings could significantly inhibit the adhesion of S. aureus. In addition, the in vitro biological evaluation displayed that the adhesion, proliferation and differentiation of MG63 cells on the Cu-incorporated coatings were enhanced as compared to those on the Cu-free coatings and Ti plates. In conclusion, the innovative Cu-incorporated nano-structured TiO2 coatings on Ti substrate with excellent antibacterial property and biological activity are promising candidates for orthopedic implant.

关键词： Micro-arc oxidation Copper Biological activity Antibacterial property

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An analysis of farmers'resource disposal methods for livestock and poultry waste and their determinants

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Chinese Journal of Population,Resources and Environment 2020年第1期18卷 49-58页

作者： Jianhua Wang junying Tao School of Business Jiangnan UniversityWuxi214122China Food Safety Research Base of Jiangsu Province Jiangnan UniversityWuxi214122China

Based on field research data on farmers in 30 counties(districts)of six cities in Shandong Province,this study systematically examines the methods of disposal of livestock and poultry waste and the factors that influence them,that is,the determinants of farmers’waste disposal behaviors,using the UTAUT theoretical framework and a disordered multi-class logit *** results show that,first,economic performance expectancy,subjective norms,farming population,and poultry and livestock breeding numbers have significant effects on the four waste recycling methods considered:direct return,compost fermentation,biogas fermentation,and fresh-packed ***,annual family income has a positive effect on the direct return ***,compost fermentation is positively affected by farmers'knowledge,distance from sources of water,and farming scale,and negatively affected by gender and marital ***,biogas fermentation is negatively affected by the age of farmers and positively affected by the farming income ratio and environmental ***,the most important factors affecting the four methods are subjective norms,farming scale,economic performance expectancy,and farming ***,this study proposes that policies to promote resource utilization of livestock and poultry waste must prioritize raising awareness among the farmers of the advantages of resource disposal of waste;provide reasonable subsidies for waste recycling and enhance policy applicability,pertinence,and motivation;strengthen the promotion of waste recycling technology and improve the practicality of lectures or training content;and improve relevant laws and regulations and enhance authority and usability.

关键词： Farmers Livestock waste Resources recovery Disordered multi-class logit model UTAUT

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Background concentrations of reactive gases and the impacts of long-range transport at the Jinsha regional atmospheric background station

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Science China Earth Sciences 2011年第10期54卷 1604-1613页

作者： LIN WeiLi XU XiaoBin SUN junying LIUXiWen WANG Ying Key Laboratory for Atmospheric Chemistry Centre for Atmosphere Watch & Services Chinese Academy of Meteorological Sciences Beijing 100081 China Tibet Institute of Plateau Atmospheric and Environmental Science Lhasa 850000 China Wuhan Central Meteorological Observatory Wuhan 430074 China

Lorentz curve fittings are applied to frequency distributions of the concentrations of O3, CO, NOx and SO2 recorded at the Jinsha regional atmospheric background station （JSH） from June 2006 to July 2007, and the peak concentrations of these species for the different seasons are obtained. The peak concentrations are considered to be representative of different background levels for certain processes. The peak concentrations are compared with the corresponding mean （median） concentrations, and the suitability and limitations of the mean （median） values as the background levels are discussed. The mean （median） values might represent the background concentrations in the region under some circumstances, but in other cases these values often underestimate or overestimate the true background concentrations owing to the transport of pollutants and other factors. The effects of air masses transported from different regions on the pollutant background concentrations are obtained by analyzing the 72-hour backward trajectories of air masses 100m above the ground at JSH, These trajectories are estimated using the HYSPLIT model and then clustered for the measurement period. The spatial distribution and seasonal variations of trajectories and the corresponding mean concentrations of O3, SO〉 NOx and CO for different clusters are analyzed. After filtering the seasonal changes in pollutant concentrations, the relative influences of air masses from different regions are obtained. The results show that JSH can be used to obtain the atmospheric background information of different air masses originating from or passing over the Yangtze River Delta, Central South China and the Jianghan Plain. Air masses from Central China, South China, and the western Yangtze River Delta contribute significantly to O3 at JSH. Air masses from the north and northeast of JSH （i.e., the Jianghan Plain, Huang-Huai Plain and North China Plain） and the south （Central South China） contribute significantly to SO2

关键词： Jinsha regional atmosphere background station background signal Lorentz curve fitting air transport O3 CO NOx SO2

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Special Issue on Automotive Lightweight

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Automotive Innovation 2020年第3期3卷 193-194页

作者： A.Erman Tekkaya junying Min Institute of Forming Technology and Lightweight ComponentsTU Dortmund University44227 DortmundGermany School of Mechanical Engineering Tongji UniversityShanghai 201804China

Lightweight is one of the core technologies to realize energy saving,to improve the safety and driving performance of vehicles,and to provide added passenger comfort as *** is of special significance for increasing cruising range of electric or hybrid-powered *** these,lightweight components use less mass and hence reduce the primary energy requirement imbedded in the ***,lightweight has always been a central topic and an important direction in the automotive field whether in the past or in the future.

关键词： weight hence driving

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Spintronic materials and devices based on antiferromagnetic metals

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Progress in Natural Science:Materials International 2017年第2期27卷 208-216页

作者： Yuyan Wang Cheng Song junying Zhang Feng Pan Department of Physics Beihang University Key Laboratory of Advanced Materials (MOE) School of Materials Science and EngineeringTsinghua University

In this paper, we review our recent experimental developments on antiferromagnet(AFM) spintronics mainly comprising Mn-based noncollinear AFM metals. Ir Mn-based tunnel junctions and Hall devices have been investigated to explore the manipulation of AFM moments by magnetic fields, ferromagnetic materials and electric fields. Room-temperature tunneling anisotropic magnetoresistance based on Ir Mn as well as Fe Mn has been successfully achieved, and electrical control of the AFM exchange spring is realized by adopting ionic liquid. In addition, promising spin-orbit effects in AFM as well as spin transfer via AFM spin waves reported by different groups have also been reviewed, indicating that the AFM can serve as an efficient spin current *** explore the crucial role of AFM acting as efficient generators, transmitters, and detectors of spin currents is an emerging topic in the field of magnetism today. AFM metals are now ready to join the rapidly developing fields of basic and applied spintronics, enriching this area of solid-state physics and microelectronics.

关键词： Antiferromagnetic metals Spintronics Tunneling anisotropic magnetoresistance Electrical manipulation

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