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High Strain Rate Superplasticity in a Micro-grained Al-Mg-sc Alloy with Predominant High Angle Grain Boundaries

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Journal of Materials science & Technology 2012年第11期28卷 1025-1030页

作者： F. c. Liu Z.Y. Ma F. c. Zhang Shenyang national Laboratory for Materials science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China State Key Laboratory of Metastable Materials science and Technology Yanshan University Qinhuangdao 066004China

Friction stir processing （FSP） was applied to extruded AI-Mg-sc alloy to produce fine-grained microstructure with a grain size of 2.2μm. Electron backsc.tter diffraction （EBSD） result showed that the grain boundary misorientation distribution was very close to a random grain assembly for randomly oriented cubes. Super- plastic investigations in the temperature range of 425-500 ℃ and strain rate range of 1x100^-2-1x10 s^-1 showed that a maximum elongation of 1500% was achieved at 475 ℃ and a high strain rate of 1x100^-2-1x10 s^-1. The FSP AI-Mg-sc exhibited enhanced superplastic deformation kinetics compared to that predicted by the constitutive relationship for superplasticity in fine-grained aluminum alloys. The origin for enhanced superplas- tic deformation kinetics in the FSP alloy can be attributed to its high fraction of high angle grain boundaries （HAGBs）. The analyses of the superplastic data and scanning electron microscopy （SEM） examinations on the surfaces of deformed specimens indicated that grain boundary sliding is the main superplastic deformation mechanism for the FSP AI-Mg-sc alloy.

关键词： Superplasticity Friction stir processing Aluminum Microstructure Friction stir welding

novel Mechanical Interface Design for Automotive Starting Systems

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Automotive Innovation 2019年第1期2卷 14-25页

作者： Alvaro c.Michelotti Jonny c.da Silva Lauro c.nicolazzi Research and Development Department Zen S.A.Industria MetalurgicaBrusqueSC 88355-100Brazil cTc-EMc-UFsc Universidade Federal de Santa Catarina(UFSC)P.O.Box 476FlorianópolisSC 88040-900Brazil

Stop-start vehicles(SSVs)represent a potential alternative for improving internal combustion engine(IcE)*** provide IcEs with the functionality of turning the engine off during traffic halts and restarting it without intervention by the *** strategy reduces fuel consumption,especially in dense urban traffic areas,and contributes to emissions reduction to meet green emissions *** most widely adopted SSV system has a mechanical interface to connect the electric starter motor to the IcE,which requires increased robustness compared with standard starting *** requirement allows the motor to withstand a higher number of engine start cycles compared with a standard starting ***,it is a critical problem for wider adoption of *** SSV systems usually are based on the conventional starting system,its durability and noise remains a critical issue to be addressed by *** typical pinion-ring gear interface uses intermittent gear meshing to form a transient coupling *** research reported here presents the development of an innovative mechanical interface for starting systems,called the permanent coupling(Pc)-type interface,which reduces noise and increases durability compared with the existing *** results obtained by a functional prototype of the Pc-type mechanical interface confirm the feasibility of the proposed *** methodology is based on a product development process integrated with lumped-parameter modeling and virtual simulation aimed at reducing failures during prototype *** new mechanical interface was proven to be a good candidate for increasing the use of SSVs in the automotive market.

关键词： Starting systems Internal combustion engines Stop-start vehicles Mechanical interface Lumped-parameter simulation

chemical characteristics of aerosols at coastal station in Hong Kong.Ⅱ. Environmental behavior of trace elements during the April 1995 to April 1996

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Journal of Environmental sciences 2004年第2期16卷 212-221页

作者： K.S.Lam Z.L.cheng S.c.Kot c.W.Tsang Department of civil and Structural Engineering the Hong Kong Polytechnic UniversityResearch Center for Eco-Environmental Sciences Chinese Academy of SciencesDepartment of Mechanical Engineering The Hong Kong University of Science & Technology Clear Water BayDepartment of Applied Biology and Chemical Technology the Hong Kong Polytechnic University Hung Hom Hong Kong ChinaBeijing 100085 ChinaHong Kong ChinaHung Hom Hong Kong China

An one-year of sampling aerosol program was carried out during the period of April 1995 to April 1996 at coastal region, cape D′Aguilar, in Hong Kong. The trace element composition of aerosol particles(TSP and PM 10 ) were measured and analyzed by using the Instrumental neutron Activation Analysis(InAA) and Inductive couple Plasma-Mass Spectrometry(IcP-MS) techniques. The results showed that the polluted elements such as: V, Zn, As, Pb, cd, Sb, I, Se, Bi, with high enrichment factor(E.F) values, are derived from anthropogenic sources, while sc, Al, Fe, Mn, Sm, La, Sr are less than 10 in E.F, these elements are related the crust and soil. The concentration of the trace elements are present seasonal variation i.e. summer low and winter high, whereas the V or noncrustal V(V *) present summer high and winter low, this phenomenon might be explained by local or regional oil combustion sources. Use three type of elemental ratio, e.g. La/Sm, Mn */V * and Bi/Al indicate that both TSP and PM 10 of La/Sm ratios are mainly related to soil and dust, Mn */V * are probably represent fossil combustion and Bi/Al are possibly associated with refuse incineration, ferromanganese alloys and aluminum production. The varimax rotation factor analysis for trace elements was performed. By means of the absolute principal component analysis(APcA) and multiple regression, the contribution of trace elements to possible sources and overall means of trace elements were estimated. The results showed that the present station is impacted by the anthropogenic species, although the quantities are different during the summertime and wintertime.

关键词： TSP PM 10 trace elements enhancement factor element ratios seasonal variation factor analysis

Flow characteristics in a parallel-plate porous channel under convective boundary conditions and triple diffusion for the non-Darcy porous matrix

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Propulsion and Power Research 2021年第4期10卷 396-411页

作者： J.c.Umavathi Department of Mathematics Gulbarga UniversityGulbarga585106KarnatakaIndia

This article inspects the effect of triple diffusion in a vertical conduit encapsulated with porous matrix and subjected to third kind boundary *** kind boundary condition is a combination of Dirichlet and neumann boundary conditions which specifies a linear combination of function and its derivative values on the *** chemical reaction along with viscous and Darcy dissipation effects are *** the Boussinesq approximation,the soultal buoyancy effects due to concentration gradients of the dispersed components are taken into *** suitable transformations,the conservation equations are reduced into dimensionless form and the dimensionless parameters evolved are thermal Grashof number (0≤Λ_(1)≤20),solutal Grashof number(for species 1 and 2,0≤Λ_(2);Λ_(3)≤20),porous (2≤σ≤8) and inertial parameters (0≤Ι≤6),Biot numbers(at the left and right walls,1≤Bi_(1);Bi_(2)≤10),Brinkman number (0≤Br≤1),schmidt numbers (0≤sc_(1);sc_(2)≤6),Soret numbers (Sr_(1) =Sr_(2) =1) and temperature difference ratio (R_(T) = 1).Adopting perturbation technique,the analytical solutions which are applicable only when the Brinkman number is less than one is *** for any values of the Brinkman number,Runge-Kutta shooting method is *** impact of selected parameters on the momentum,heat and dual species concentration fields are presented in the form of *** solutions computed by numerical method are justified by comparing with the analytical *** numerical and analytical solutions are equal in the absence of Darcy and viscous dissipations and the discrepancy advances as the Brinkman number *** the solutions obtained are also justified by comparing the results with Zanchini[1]in the absence of chemical reaction for clear *** thermal field is augmented with the Brinkman number for symmetric and asymmetric Biot *** the profiles are highly distinct at the cold plate for unequal Biot numbers

关键词： Mixed convection Robin boundary conditions Darcy-Forchheimer-Brinkman model Soret number Runge-Kutta shooting method

Differentiation transforming system

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Progress in natural science:Materials International 2009年第3期19卷 397-406页

作者： Qiang chenga,b,c,*, Haibin Zhang d, Bin Wanga, Yonghua Zhao c a LASG, Institute of Atmospheric Physics, chinese Academy of sciences, Beijing 100029, PR china b LSEc, Institute of computing Mathematics, chinese Academy of sciences, Beijing 100080, PR china c sc, Institute of computer network Information center, chinese Academy of sciences, Beijing 100190, PR china d college of Applied sciences, Beijing University of Technology, Beijing 100124, PR china LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 PR China LSEc Institute of Computing Mathematics Chinese Academy of Sciences Beijing 100080 PR China sc Institute of Computer Network Information Center Chinese Academy of Sciences Beijing 100190 PR China college of Applied sciences Beijing University of Technology Beijing 100124 PR China

The differentiation transforming (DFT) system is developed to produce the tangent linear codes, which is used to calculate the Jaco- bian- and the Hessian-vector products with no truncation errors. This paper first gives the introduction of the functionality and features of the DFT system, and then discusses several techniques for the implementation of automatic differentiation tools, including data depen- dence analysis, singular differentiation and code optimization. Finally, the codes generated with DFT used in several applications have been demonstrated.

关键词： Jacobian Hessian Tangent linear model Automatic differentiation

Effects of Solar Radiation on Satellite Antenna

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Effects of Solar Radiation on Satellite Antenna

Finite Element Simulation on Thermal Fatigue of a Turbine Blade with Thermal Barrier coatings

IEEE 2005 International Symposium on Microwave, Antenna, Propagation and EMc Technologies for Wireless communications

作者： Qian Qiaoyuan* Wen Mo Shanghai Spaceflight Institute of tt&c and Telecommunication

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Journal of Materials science & Technology 2014年第4期30卷 371-380页

作者： L.Yang Q.X.Liu Y.c.Zhou W.G.Mao c.Lu Key Laboratory of Low Dimensional Materials & Application Technology(Ministry of Education) Xiangtan University Faculty of Materials Optoelectronic & PhysicsXiangtan University Department of Mechanical Engineering Curtin University

In this paper, a finite element model was developed for a turbine blade with thermal barrier coatings to investigate its failure behavior under cyclic thermal loading. Based on temperature and stress fields obtained from finite element simulations, dangerous regions in ceramic coating were determined in terms of the maximum principal stress criterion. The results show that damage preferentially occurs in the chamfer and rabbet of a turbine blade with thermal barrier coatings and its thermal fatigue life decreases with the increase of thermal stress induced by high service temperature.

关键词： Turbine blade Thermal barrier coatings Finite element model Thermal fatigue Life prediction

Linking sedimentary provenance,climate and tectonics in the neoproterozoic SeridóBelt,Borborema Province(nE Brazil)

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Geoscience Frontiers 2023年第6期14卷 414-431页

作者： carlos V.A.Ribeiro Marcos c.c.Sales Armando L.S.de Oliveira Ricardo Sallet Programa de Pós-graduação em Geologia Instituto de GeociênciasUniversidade de Brasília(UnB)CEP 70910-900 BrasíliaDFBrazil Programa de Pós-Graduação em Geociências Universidade Federal de PernambucoDepartamento de GeologiaCentro de Tecnologia e GeociênciasAv.da ArquiteturaCEP 50740-530 RecifePEBrazil Departamento de Geologia Universidade Federal do Rio Grande do NorteCEP 59078-970 NatalRNBrazil

The SeridóBelt,at the extreme northeast of Brazil,is one of the several neoproterozoic mobile belts related to the Brasiliano/Pan-African Orogeny in Western *** lithostratigraphy of the SeridóBelt comprises basal quartzites and metaconglomerates(Equador Formation)overlain by hornblende-bearing paragneisses,calc-silicate rocks and marbles(Jucurutu Formation)and biotiteschists(SeridóFormation).We investigated the sedimentary provenance of these rocks based on an integration of compiled whole-rock geochemistry,Sm-nd isotopes,U-Pb detrital zircon ages and a new set of whole-rock trace elements *** Formation quartzites have major and trace elements patterns that resemble cratonic sandstones,with a typical felsic provenance consistent with the isotopic composition of plutonic Archean to Paleoproterozoic basement *** proxies suggest that these rocks were deposited in fresh waters under anoxic conditions and moderate to intense weathering conditions(cIA=58–79).A shift in provenance led to an increase in intermediate-mafic sources during the deposition of the Jucurutu and Seridó*** elements from rock types in these units are nearly identical,yet they differ on the contents of some high field-strength elements(e.g.,sc,V and ni),which are higher in the SeridóFormation than average *** proxies show similar depositional environments,with brackish to marine conditions for the Jucurutu and Seridóformations under anoxic to euxinic *** conditions are consistently lower in the Jucurutu Formation(cIA=58–66)in comparison with the SeridóFormation(cIA=60–88).compiled U-Pb data suggest maximum depositional ages of 633±11 Ma and 633±6 Ma for Jucurutu and Seridóformations,respectively,suggesting deposition following the ca.645–635 Ma Marinoan *** compared the geochemistry of the SeridóFormation schists with currently exposed basement rocks and showed a strong affinity with neoproterozoic arc-related

关键词： Whole-rock geochemistry Marinoan Glaciation U-Pb detrital zircon Brasiliano Orogeny

瑞典北部基茹纳地区铜矿床含矿植被的实例研究

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干旱区地理 1992年第2期15卷 89-94页

作者： H.Isaksson M.sc L.c.Adersson M.sc T.Lic 包安明瑞典地质公司瑞典空间有限公司

瑞典北部基茹纳地区土壤中含铜量丰富,被认为与该区露天草场一种叫“威斯卡里亚、阿尔盘纳”的小花分布一致。在威斯卡里亚和帕特哈瓦热中部两种不同铜矿化区均发现类似情况。本研究利用卫星资料,航空数字图象高程图和航空植被图对植被... 详细信息

瑞典北部基茹纳地区土壤中含铜量丰富,被认为与该区露天草场一种叫“威斯卡里亚、阿尔盘纳”的小花分布一致。在威斯卡里亚和帕特哈瓦热中部两种不同铜矿化区均发现类似情况。本研究利用卫星资料,航空数字图象高程图和航空植被图对植被的含矿性进行分析,结果与其它地质方法所提供的重点靶区完全吻合。

关键词：铜矿矿床植被图象传感器