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A new beam element for analyzing geometrical and physical nonlinearity

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Acta Mechanica Sinica 2010年第4期26卷 605-615页

作者： Xiao-Feng Wang qing-shan yang Qi-Lin Zhang College of Civil Engineering Tongji University 709 Civil Building 1239 Siping Road Shanghai 200092 China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044 China

Based on Timoshenko＇s beam theory and Vlasov＇s thin-walled member theory, a new model of spatial thin-walled beam element is developed for analyzing geometrical and physical nonlinearity, which incorporates an interior node and independent interpolations of bending angles and warp and takes diversified factors into consideration, such as traverse shear deformation, torsional shear deformation and their coupling, coupling of flexure and torsion, and the second shear stress. The geometrical nonlinear strain is formulated in updated Lagarange （UL） and the corresponding stiffness matrix is derived. The perfectly plastic model is used to account for physical nonlinearity, and the yield rule of von Mises and incremental relationship of Prandtle-Reuss are adopted. Elastoplastic stiffness matrix is obtained by numerical integration based on the finite segment method, and a finite element program is compiled. Numerical examples manifest that the proposed model is accurate and feasible in the analysis of thin-walled structures.

关键词： Spatial beams Thin-walled section Beam element Geometrical and physical nonlinearity FEM

Effect of Extrusion Strain Path on Microstructure and Properties of AZ31 Magnesium Alloy Sheet

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Acta Metallurgica Sinica(English Letters) 2015年第10期28卷 1257-1263页

作者： qing-shan yang Bin Jiang Zu-Jian Yu qing-Wei Dai Su-Qin Luo School of Metallurgy and Material Engineering Chongqing University of Science and Technology Chongqing Academy of Science and Technology

The mechanical properties of AZ31 magnesium alloy sheets processed by different extrusion strain paths were examined in correlation with concurrent microstructure and texture evolution. The conventional extrusion（CE） and asymmetric extrusion（ASE） paths were performed on Mg alloy sheets. The textures at near surface and mid-layer of ASE sheets were various throughout sheet thickness direction as a result of extra asymmetric shear strain. This can stimulate the orientation of（0002） basal planes to incline approximately 12° toward the shear direction. Moreover, the basal texture of ASE sheet was weakened compared with CE one. Enhancing the ambient formability of extruded Mg alloy sheet fabricated by ASE path was accomplished by the tilted weak basal texture.

关键词： Mg alloy Extrusion Microstructure Texture Mechanical property Formability

Influence of Extrusion Joint on Microstructural Evolution and Properties of Mg Alloy Sheet

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Acta Metallurgica Sinica(English Letters) 2016年第5期29卷 475-482页

作者： qing-shan yang Zu-Jian Yu Hu-Cheng Pan qing-Wei Dai Jian-Hui Li School of Metallurgy and Materials Engineering Chongqing University of Science and TechnologyChongqing 401331China Chongqing Academy of Science and Technology Chongqing 401123China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110819China

The mechanical behaviour of AZ31 magnesium alloy sheet with the extrusion joint （EJ） was evaluated. Extruded joint of AZ31 alloy sheets was obtained by the hot extrusion process. Tensile tests were carried out along the extrusion direction at room temperature, and both the non-uniform plastic deformation and the fracture behaviour were studied. It is found that the samples with EJ present significantly deteriorated mechanical properties compared with the EJ- free counterpart. Inhomogeneous rnicrostructure distribution around EJ zone brings in the uncoordinated deformation due to the high density of {1012} twins which were readily activated during plastic deformation.

关键词： Mg alloy Microstructure Twin Texture Extrusion joint

Moderate Deviations for the Parameter Estimation in the Fractional Ornstein-Uhlenbeck Process with H∈(0,1/2)

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Acta Mathematicae Applicatae Sinica 2024年

作者： Hui JIANG qing-shan yang School of Mathematics Nanjing University of Aeronautics and Astronautics MOE Key Laboratory of Applied Statistics School of Mathematics and StatisticsNortheast Normal University

Abstract In this paper,we study the asymptotic properties for estimators of two parameters in the drift function in the ergodic fractional Ornstein-Uhlenbeck process with Hurst index H∈(0,1/2).The Cramér-type moderate deviations,as well as the moderation deviations with explicit rate function can be *** main methods consist of the deviation inequalities and Cramér-type moderate deviations for multiple WienerIt?integrals,as well as the asymptotic analysis techniques.

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Interfacial reaction between AZ91D magnesium alloy melt and mild steel under high temperature

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China Foundry 2024年第2期21卷 159-167页

作者： Jia-hong Dai Jian-yue Zhang Bin Jiang Xiang-jun Xu Zhong-tao Jiang Hong-mei Xie qing-shan yang Guo-qing Zhang College of Materials Science and Engineering Yangtze Normal UniversityChongqing 408100China National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China Chongqing Jiulongyuan High-tech Industry Group Co. Ltd.Chongqing 400080China Loncin Industry Co. Ltd.Chongqing 400080China Department of Materials Science and Engineering The Ohio State UniversityColumbusOH 43210USA Chongqing Key Laboratory of Materials Surface&Interface Science Chongqing University of Arts and SciencesChongqing 402160China School of Metallurgy and Material Engineering Chongqing University of Science and TechnologyChongqing 401331China

The metallurgical quality control of magnesium(Mg)and Mg alloys in melting process is required to ensure a satisfied mechanical and corrosion performance,while the typical used steel crucible introduces impurities and interfacial interaction during melting ***,a systematic study about impurities diffusion and interfacial interaction between molten Mg and steel is *** the present study,the interfacial reaction between molten AZ91D Mg alloy and mild steel during melting process was investigated with the melting temperatures of 700℃,750℃ and 800℃.The results show that Al(Fe,Mn)intermetallic layer is the intermetallic primarily formed at the interfaces of AZ91D melt and mild ***,Al_(8)(Mn,Fe)5is indexed between Al(Fe,Mn)and ***_(3)C appears between the mild steel and Al(Fe,Mn)at 700℃ and 750℃,but absent at 800℃ due to the increased solubility of carbon in Mg *** is found that the growth of the intermetallic layer is controlled by diffusion mechanism,and Al and Mn are the dominant diffusing species in the whole interfacial reaction *** measuring the thickness of different layers,the growth constant was *** increases from 1.89(±0.03)×10^(-12)m^(2)·s^(-1)at 700℃ to 3.05(±0.05)×10^(-12)m^(2)·s^(-1)at 750℃,and 5.18(±0.05)×10^(-12)m^(2)·s^(-1)at 800℃.Meanwhile,the content of Fe is linearly increased in AZ91D with the increase of holding time at 700℃ and 750℃,while it shows a significantly increment after holding for 8 h at 800℃,indicating holding temperature is more crucial to determine the Fe content of AZ91D than holding time.

关键词： AZ91D mild steel interface reaction intermetallic growth kinetics

Robust microporous metal-organic framework with high moisture tolerance for efficient separation of propylene from propane

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Chinese Journal of Structural Chemistry 2023年第2期42卷 29-34页

作者： shan-qing yang Lei Zhou Bo Xing Ying-Hui Zhang Tong-Liang Hu School of Materials Science and Engineering National Institute for Advanced MaterialsNankai UniversityTianjin300350China

Adsorptive separation of propylene(C_(3)H_(6))from propylene/propane(C_(3)H_(8))is desired to replace energy-intensive cryogenic distillation for its energy efficiency,economical viability,and environment *** this work,we report a cupper-based robust microporous metal-organic framework,Cu-Hmpba,constructed by the hard soft acid-base principle using the bifunctional pyridylcarboxylate ligand featuring methyl group,for high-efficient separation of the propylene/propane *** the synergistic effect of the protective group and hard soft acid base principle,Cu-Hmpba possesses good solvents stability,especially water ***-Hmpba exhibits the adsorption capacity of C_(3)H_(6)with 2.10 mmol g^(-1)and good equimolar C_(3)H_(6)/C_(3)H_(8)selectivity with 2.24 at ambient *** gas adsorption experiments,IAST selectivity calculations and theoretical calculations comprehensively support the selective adsorption toward C_(3)H_(6)among C_(3)H_(6)/C_(3)H_(8)***,it could maintain stable under moisture environment,suggesting its potential for the industrial separation of C_(3)H_(6)/C_(3)H_(8)*** results of experiments and simulations demonstrate that the Cu-Hmpba would be a candidate adsorbent for the separation and purification of light hydrocarbons,and this work provides the insight of syn-thesizing stable MOF materials for separating high-value chemicals.

关键词： Metal-organic framework Adsorptive separation Propylene/propane separation Energy efficient

Precision measurement of the Newtonian gravitational constant

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National Science Review 2020年第12期7卷 1803-1817页

作者： Chao Xue Jian-Ping Liu qing Li Jun-Fei Wu shan-qing yang Qi Liu Cheng-Gang Shao Liang-Cheng Tu Zhong-Kun Hu Jun Luo Tian Qin Research Center for Gravitational Physics & School of Physics and Astronomy Sun Yat-sen University(Zhuhai Campus) MOE Key Laboratory of Fundamental Physical Quantities Measurement & Hubei Key Laboratory of Gravitation and Quantum Physics PGMF and School of PhysicsHuazhong University of Science and Technology

The Newtonian gravitational constant G,which is one of the most important fundamental physical constants in nature,plays a significant role in the fields of theoretical physics,geophysics,astrophysics and *** G was the first physical constant to be introduced in the history of science,it is considered to be one of the most difficult to measure accurately so *** the past two decades,eleven precision measurements of the gravitational constant have been performed,and the latest recommended value for G published by the Committee on Data for Science and Technology(CODATA) is(6.674 08 ±0.000 31) × 10m~3 kgswith a relative uncertainty of 47 parts per *** uncertainty is the smallest compared with previous CODATA recommended values of G;however,it remains a relatively large uncertainty among other fundamental physical *** this paper we briefly review the history of the G measurement,and introduce eleven values of G adopted in CODATA 2014 after 2000 and our latest two values published in 2018 using two independent methods.

关键词： precision measurement Newtonian gravitational constant CODATA

A review of high-performance MEMS sensors for resource exploration and geophysical applications

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Petroleum Science 2022年第6期19卷 2631-2648页

作者： Hua-Feng Liu Zhi-Cai Luo Zhong-Kun Hu shan-qing yang Liang-Cheng Tu Ze-Bing Zhou Michael Kraft National Precise Gravity Measurement Facility(PGMF)and School of Physics Huazhong University of Science and TechnologyWuhanHubei430074China Institute of Geophysics Huazhong University of Science and TechnologyWuhanHubei430074China TianQin Research Center for Gravitational Physics and School of Physics and Astronomy Sun Yat-sen University(Zhuhai Campus)ZhuhaiGuangdong519082China Nanchang Research Institute Sun Yat-sen UniversityNanchangJiangxi330099China ESAT-MNS University of LeuvenLeuvenBelgium

MEMS sensors have the advantages of small volume,lightweight,and low cost,therefore,have been widely used in the fields of consumer electronics,industry,health,defence,and *** their ever-improving performance,MEMS sensors have also started to be used in resource exploration and geophysical ***,the requirements of high-precision MEMS sensors for geophysical applications have not been specified in ***,this paper systematically analyzes the requirements of high-performance MEMS sensors for prospecting and geophysical applications,including seismic surveillance,Earth tide,volcanic activity monitoring for natural disasters;seismic,gravity,and magnetic resource prospecting;drilling process monitoring and local gravity measurement for gravity aided *** on the above applications,this paper summarizes the state-of-the-art of research on high-performance MEMS sensors for resource exploration and geophysical *** off-the-shelf MEMS sensors have been used for earthquake monitoring,seismic exploration and drilling process monitoring,and a range of MEMS research prototype sensors have successfully been employed for Earth tides measurement and are promising to be used for gravity *** magnetometers should have a lower noise floor to meet the demand for magnetic *** gravity gradiometers are still under early development and will not be deployable in *** MEMS sensors hold the advantages of low-cost,high integration,and capability of working in extreme environments;therefore,they are likely to gradually replace some conventional geophysical instruments in some application areas.

关键词： Accelerometer Seismometer Gravimeter Tilt-meter Magnetometer

Information Heterogeneity: Implications for Liquidity and Price Efficiency

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Acta Mathematicae Applicatae Sinica 2024年

作者： Zhi-hua LI Hong LIU qing-shan yang Northeast Normal University KLAS and School of Mathematics and Statistics

This paper discusses a model about information heterogeneity. The market size, information attention and information asymmetry affect market liquidity and price information. Larger market size can lead to an increase in market liquidity and the release of price information; however, traders who possess higher information attention can quickly affect price efficiency through their trading, leading to increased price *** addition, the increase in asymmetry scale will lead to a decrease in liquidity and a reduction in the release of price information. Under information asymmetry, large trading groups attract followers, thereby increasing market liquidity and trading intensity.

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