检索结果-南通市图书馆

Time-dependent lateral response of pile embedded in elasto-plastic soil

在线全文

学校读者我要写书评

暂无评论

journal of Central south University 2010年第2期17卷 372-380页

作者： j.M.ABBAs Z.h.ChIK M.R.TAhA q.s.M.shAFIqU Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia Department of Civil Engineering Nahrain University

A two-dimensional （2D） finite element analysis was carried out to assess the time-dependent behavior of single vertical pile embedded in elasto-plastic soil. The finite element analyses were carried out using the linear elastic model for the structure of the pile, while the Mohr-Coulomb model was used for representing the soil behavior surrounding the pile. The study includes cohesionless and cohesive soil to assess the lateral response of pile in the two types of soil. The whole geoteehnical model is suitable for problem of piles to determine the design quantities such as lateral deformation, lateral soil stress and its variation with time. The model is verified based on the results of published cases and there is good comparison between the results of published ease and the present simulation model. It is found that, the pile in cohesionless soil has more resistance in the rapid loading and less one in the long term loading. On the other hand, the pile in cohesive soil shows opposite behavior.

关键词： single pile consolidation effect lateral response soil pressure 2D finite element method

sUBsTRATE MATERIALs FOR POLY-CsiTF sOLAR CELLs: OPTIMIZATION OF sILICON shEET FROM POWDER

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica sinica(English Letters) 2005年第3期18卷 184-188页

作者： q.Ban h.shen X.j.wang X.W.Zou Z.C.Liang stateKeyLaboratoryofOptoelectronicMaterialsandTechnologies DepartmentofPhysicsandEngineeringZhongshan（SunYat-sen）UniversityGuangzhou510275China GuangzhouInstituteofEnergyConversion TheChineseAcademyofSciencesGuangzhou510275China

The optimization of silicon sheet from powder (ssP) technology as polycrystalli ne silicon thin film (poly-CsiTF) solar cells' substrate materials is studied by orthogonal design experimental method. Based on technological optimization of s sP prepared from electronic grade silicon powder, ssP solar cell devices with si mple structure are prepared and the effect of ssP substrate is discussed. Up to now, the conversion efficiency of the prepared solar cells on low purity ssP sub strate with fundamental structure has reached 8.25% (with area of 1cm×1cm).

关键词： poly-CsiTF ssP substrate material

Two-stage hall-Petch relationship in Cu with recrystallized structure

在线全文

学校读者我要写书评

暂无评论

journal of Materials science & Technology 2020年第13期47卷 31-35页

作者： Y.Z.Tian Y.P.Ren s.Gao R.X.Zheng j.h.wang h.C.Pan Z.F.Zhang N.Tsuji G.W.qin Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China state Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Department of Materials science and Engineering Kyoto UniversityYoshida-honmachiSakyo-kuKyoto 606-8501Japan Elements strategy Initiative for structural Materials(EsIsM) Kyoto UniversityYoshida-honmachiSakyo-kuKyoto606-8501Japan Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education School of Materials Science and EngineeringBeihang UniversityBeijing 100191China state Grid Urban and Rural Electric Power Design Research(Beijing)Co.Ltd Beijing 100078China Laboratory of Fatigue and Fracture for Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China school of Materials science and Engineering University of Science and Technology of ChinaHefei 230026China

Although Cu was studied extensively,the hall-Petch relationship was mainly reported in the coarsegrained *** this work,fully recrystallized Cu specimens with a wide grain size regime of 0.51–14.93μm manifest a two-stage hall-Petch *** is a critical grain size of 3μm that divides stagesⅠandⅡwhere the hall-Petch slope k value are quite *** stageⅡis supposed to be validified down to 100 nm at least by comparing with a Cu-Ag *** critical grain size varies in different materials systems,and the underline mechanisms are discussed based on the dislocation glide modes.

关键词： Cu Yield strength hall-Petch relationship Ultrafine grain Recrystallization

GRACE terrestrial water storage data assimilation based on the ensemble four-dimensional variational method PODEn4DVar:Method and validation

在线全文

学校读者我要写书评

暂无评论

science China Earth sciences 2015年第12期58卷 371-384页

作者： sUN qin XIE Zhenghui TIAN Xiangjun state Key Laboratory of Numerical Modelling for Atmospheric sciences and Geophysical Fluid Dynamics(LAsG) Institute of Atmospheric PhysicsChinese Academy of Sciences University of Chinese Academy of sciences Numerical Weather Prediction Center China Meteorological Administration

seasonal and interannual changes in the Earth's gravity field are mainly due to mass exchange among the atmosphere,ocean,and continental water *** terrestrial water storage changes,detected as gravity changes by the Gravity Recovery and Climate Experiment(GRACE) satellites,are mainly caused by precipitation,evapotranspiration,river transportation and downward infiltration *** this study,a land data assimilation system LDAs-G was developed to assimilate the GRACE terrestrial water storage(TWs) data into the Community Land Model(CLM3.5) using the POD-based ensemble four-dimensional variational assimilation method PODEn4 DVar,disaggregating the GRACE large-scale terrestrial water storage changes vertically and in time,and placing constraints on the simulation of vertical hydrological variables to improve land surface hydrological *** ideal experiments conducted at a single point and assimilation experiments carried out over China by the LDAs-G data assimilation system showed that the system developed in this study improved the simulation of land surface hydrological variables,indicating the potential of GRACE data assimilation in large-scale land surface hydrological research and applications.

关键词： data assimilation land surface model terrestrial water storage ensemble four-dimensional variational data assimilation method

同方期刊数据库

Constructing two-scale network microstructure with nano-Ti5si3 for superhigh creep resistance

在线全文

学校读者我要写书评

暂无评论

journal of Materials science & Technology 2019年第8期35卷 1532-1542页

作者： Y.jiao L.j.huang s.L.Wei h.X.Peng q.An s.jiang L.Geng state Key Laboratory of Advanced Welding and joining Harbin Institute of TechnologyHarbin 150001 China Center of Analysis and Measurement Harbin Institute of TechnologyHarbin 150001 China Department of Materials science and Engineering Massachusetts Institute of TechnologyCambridge MA02139 USA Institute for Composites science Innovation (InCsI) School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027 China

The improvement of mechanical properties must be achieved by designing and constructing more suitable microstructure,such as hierarchical *** order to significantly enhance the creep resistance of titanium matrix composites(TMCs),two-scale network microstructure was constructed including the first-scale network(h micro-TiB whisker(TiBw)reinforcement and the second-scale network(h nano-Ti5si3 reinforcement by powder metallurgy and in-situ *** results showed that the creep rate of the composite was remarkably reduced by an order of magnitude compared with the Ti6Al4V alloy at 550℃,600℃,650℃ under the stresses between 100 MPa and 350 ***,the rupture time of the composite was increased by 20 times,compared with that of the Ti6Al4 Valloy at 550℃/300 *** superior creep resistance could be attributed to the hierarchical *** micro-TiBw reinforcement in the first-scale network boundary contributed to creep resistance primarily by blocking grain boundary sliding,while the nano-Ti5si3 particle in the second-scale network boundary mainly by hindering phase boundary *** addition,the nano-Ti5si3 particle was dissolved,and precipitated with smaller size than the primary *** phenomenon was attributed to si element diffusion under high temperature and external stress,which could further continuously enhance the creep ***,the creep rate during steady-state stage was significantly decreased,which manifested superior creep resistance of the composite.

关键词： Titanium matrix composite Two-scale network microstructure Nano-Ti5si3 Creep Powder metallurgy

Dynamic Impact of high-Density Aluminum Foam

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica solida sinica 2022年第2期35卷 198-214页

作者： q.Peng j.Xie h.s.Ma X.Ling X.Liu Y.G.Wei LNM Institute of MechanicsChinese Academy of SciencesBeijing 100190China school of Engineering science University of Chinese Academy of SciencesBeijing 100049China school of Engineering and Technology China University of GeosciencesBeijing 100083China College of Engineering Peking UniversityBeijing 100871China

high-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 *** this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,*** on the derived model,we performed finite element simulation to study the impact response of the present *** dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after *** the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic.

关键词： high density aluminum Foam Deshpande-Fleck model Finite element method Impact analysis Plastic wave

A Novel Design and Fabrication of Magnetic Random Access Memory Based on Nano-ring-type Magnetic Tunnel junctions

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

journal of Materials science & Technology 2007年第3期23卷 304-306页

作者： X.F.han h.X.Wei Z.L.Peng h.D.Yang j.F.Feng G.X.Du Z.B.sun L.X.jiang q.h.qin M.Ma Y.wang Z.C.Wen D.P.Liu W.s.Zhan state Key Laboratory of Magnetism Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Science Beijing 100080 China

Nano-ring-type magnetic tunnel junctions （NR-MTjs） with the layer structure of Ta（5）/Ir22Mn78（10）/ Co75Fe25（2）/Ru（0.75）/CoooFe20B20（3）/Al（0.6）-oxide/Co60Fe20B20（2.5）/Ta（3）/Ru（5）（thickness unit： nm） were nano-fabricated on the si（100）/siO2 substrate using magnetron sputtering deposition combined with the optical lithography, electron beam lithography （EBL） and Ar ion-beam etching techniques. The smaller NR-MTjs with the inner- and outer-diameter of around 50 and 100 nm and also their corresponding NR-MTj arrays were nano-patterned. The tunnelling magnetoresistance （TMR ＆ R） versus driving current （I） loops for a spin-polarized current switching were measured, and the TMR ratio of around 35% at room temperature were observed. The critical values of switching current for the free Co60Fe20B20 layer relative to the reference Co6oFe2oB2o layer between parallel and anti-parallel magnetization states were between 0.50 and 0.75 mA in such NR-MTjs. It is suggested that the applicable MRAM fabrication with the density and capacity higher than 256 Mbit/inch2 even 6 Gbite/inch2 are possible using both I NR-MTj＋1 transistor structure and current switching mechanism based on based on our fabricated 4×4 MRAM demo devices.

关键词： Nano-ring-type magnetic tunnel junctions NR-MTj MRAM spin polarization spin transfer effect

Maximal Cohen-Macaulay modules over a noncommutative 2-dimensional singularity

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2019年第5期14卷 923-940页

作者： Xiaoshan qin Yanhua wang james ZhANG China Academy of Electronics and Information Technology Beijing 100041China school of Mathematical sciences Shanghai Center for Mathematical SciencesPudan UniversityShanghai 200433China school of Mathematics Shanghai Key Laboratory of Financial Information TechnologyShanghai University of Finance and EconomicsShanghai 200433China Department of Mathematics University of WashingtonSeattleWA 98195USA

We study properties of graded maximal Cohen-Macaulay modules over an N-graded locally finite,Auslander Gorenstein,and Cohen-Macaulay algebra of dimension *** a consequence,we extend a part of the McKay correspondence ... 详细信息

关键词： Noncommutative quasi-resolution Artin-schelter regular algebra Maximal Cohen-Macaulay module pretzeled quivers

hot Deformation Behavior and Processing Maps of a high Al-low si Transformation-Induced Plasticity steel: Microstructural Evolution and Flow stress Behavior

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica sinica(English Letters) 2018年第5期31卷 503-514页

作者： h.q.huang h.s.Di N.Yan j.C.Zhang Y.G.Deng R.D.K.Misra j.P.Li state Key Laboratory of Rolling and Automation Northeastern University Laboratory for Excellence in Advanced steel Research Department of Metallurgical Materials and Biomedical Engineering University of Texas at El Paso

hot deformation behavior of a high Al-low si transformation-induced plasticity（TRIP） steel was studied by an MMs-300 thermo-simulation machine at the temperature range of 1050–1200℃ and strain rate range of 0.01–10s^（-1）. The constitutive equations of the TRIP steel were established at high temperature by fitting the strain factor with a sixth-order polynomial. The instability during hot rolling was discussed using processing maps. The results reveal that two types of flow stress curves（dynamic recrystallization and dynamic recovery） were observed during the hot compression of the high Al-low si TRIP steel. Flow stress decreased with increasing deformation temperature and decreasing strain rate. The predicted flow stress of experimental TRIP steel is in agreement with the experimental values with an average absolute relative error of 4.49% and a coefficient of determination of 0.9952. According to the obtained processing maps, the TRIP steel exhibits a better workability at strain rate of 0.1s^（-1） and deformation temperature of 1200℃ as compared to other deformation conditions.

关键词： TRIP steel hot compression Constitutive equation Processing maps