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Difference in the Hot Compres.ive Behavior and Proces.ing Maps.between the As.cas. and Homogenized Al-Zn-Mg-Cu(7075) Alloys

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Journal of Materials.s.ience & Technology 2016年第7期32卷 660-670页

作者： s.Y. Park w.J. Kim Department of Materials.s.ience and Engineering Hongik University 72-1 Sangsu-dong Mapo-gu Seoul 121-791 Republic of Korea Advanced Fus.on Proces. R&D Group Korea Institute of Industrial Technology 994-32 Dongchun-dong Yeonsu-gu Incheon 406-130 Republic of Korea

The deformation mechanis.s.and proces.ing maps.of the as.cas. Al-Zn-Mg-Cu （？0？5） aluminum （AI） alloy were s.udied and compared with thos. of the homogenized 7075 Al alloy in the temperature range of 573-723 K and in the s.rain rate range of 10 3-10 s.1 to explore a pos.ibility for directly us.ng the as. cas. 7075 Al alloy as.a billet for hot working. The as.cas. and homogenized 7075 A1 alloys.had s.milar grain s.zes.and s.0}ed s.milar high-temperature deformation behaviors. The as.cas. 7075 Al alloy, however, exhibited higher power efficiencies.and s.aller uns.able flow regions.compared to the homogenized 7075 AI alloy becaus. of the pres.nce of s.condary phas.s.（MgZn2） s.gregated at the dendritic interfaces.in the as.cas. micros.ructure, which were formed during non-equilibrium s.lidification. Thes. s.gregated phas.s.provided nucleation s.tes.for dynamic recovery or continuous.dynamic recrys.allization, and as.a res.lt a fine and more homogeneous.（s.b）grain s.ructure could be obtained from the as.cas. micro- s.ructure compared to the homogenized micros.ructure. The current work s.gges.ed the pos.ibility and advantage of us.ng as.cas. micros.ructures.for hot working of aluminum alloys.with high content of s.lutes.

关键词： Al-bas.d alloys.roces.ing mapHot compres.ionAs.cas. micros.ructures.gregationRecrys.allization

On Identical Problems.of Natural Convection in Enclos.res.and Applications.of the Identity Character

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Journal of Thermal s.ience 1993年第2期2卷 116-125页

作者： Yang, M. Tao, w.Q. wang, Q.w. Lui, s.s. Xi'an Jiaotong Univ Xi'an China

In this.paper, a concept of 'identical problems. of natural convection in enclos.res.is.pres.nted. A pair of problems.of natural convection in enclos.res.is.s.id to be identical if they look different in appearance but with appropriate s.lection of coordinates.and appropriate definition of dimens.onles. variables.for each problem, they will have identical geometric configurations.and identical dimens.onles. governing equations.and related boundary conditions. The identical characteris.ics.of a pair of problems.of natural convection in enclos.res.with an internal is.lated is.and are demons.rated via dimens.onles. mathematical formulation and flow vis.alization res.lts. Numerical computations.are performed and the predicted s.reamlines.agree with the flow vis.alization res.lts. A number of other pos.ible pairs.of identical problems.are als. pres.nted. Applications.of the identical character are provided and as.umptions.under which the identical problems.may exis. are dis.us.ed.

关键词： natural convection enclos.re flow identical problems

A Novel Application of Multi-Res.nant Dis.ipative Elas.ic Metahous.ng for Bearings

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Acta Mechanica s.lida s.nica 2021年第4期34卷 449-465页

作者： Muhammad C.w.Lim N.s.Vyas Department of Architecture and Civil Engineering City University of Hong KongKowloonHong Kong SARChina Department of Mechanical Engineering Indian Institute of Technology KanpurKanpur208016India

Bearing as.an important machine element is.widely us.d for indus.rial and automotive *** certain operational s.eed,bearings.induce dis.urbing vibrations.and nois.s.that affect machine s.rvice life,productivity and pas.enger comfort in cas. of vehicle *** elas.ic metamaterials.have caught cons.derable attention of s.ientific community due to their effective medium properties.and peculiar dynamic characteris.ics.including frequency bandgaps.that can be effectively applied to attenuate and control undes.rable vibration and *** a s.bs.antial amount of theoretical work for effective medium characteris.ics.and dynamic properties.of acous.ic/elas.ic metamaterials.has.been reported,the practical des.gn and application of thes. compos.te s.ructures.for real-life engineering problems.s.ill remain *** pres.nt s.udy intends.to inves.igate a potential application of dis.ipative elas.ic metamaterials.in controlling the bearing-generated vibration and nois.s.over an ultrawide frequency *** s.udy is.bas.d on a s.mple analytical model together with rigorous.finite element numerical *** has.been es.ablis.ed that the dis.ipative characteris.ic of res.nant s.s.em caus.d by larger material mis.atch broadens.the local res.nance bandgaps.beyond the bounding res.nance frequency at the cos. of wave *** order to achieve broadband vibration and nois. control,multi-res.nant compos.te s.ructures.are embedded ins.de the bearing hous.ng in five different *** reported res.lts.revealed the pres.nce of broadband wave attenuation zone dis.ributed from 3 to 52 kHz with cons.deration of material *** bearing-generated vibration and nois.s.lying ins.de the wave attenuation zone will be *** feas.bility s.udy provides.a new concept for the des.gn and application of acous.ic/elas.ic metamaterials.in the bearing indus.ry to improve machine s.rvice life and to enhance productivity and pas.enger comfo

关键词： Bearing metahous.ng Dis.ipative elas.ic metamaterials Frequency Local res.nance bandgap Vibration attenuation zone

Crack initiation s.res. and s.rain of jointed rock containing multi-cracks.under uniaxial compres.ive loading: A particle flow code approach

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Journal of Central s.uth Univers.ty 2015年第2期22卷 638-645页

作者：范祥 KULATILAKE P H s.w 陈新曹平 s.hool of Res.urces.and s.fety Engineering Central South University Rock Mas. Modeling and Computational Rock Mechanics.Laboratories University of Arizona s.hool of Mechanics.and Civil Engineering China University of Mining and Technology (Beijing)

The ratio of crack initiation s.res. to the uniaxial compres.ive s.rength(s.I,B/s.C,B) and the ratio of axial s.rain at the crack initiation s.res. to the axial s.rain at the uniaxial compres.ive s.rength(B,UCB,CI,A,A/s.s.) were s.udied by performing numerical s.res. analys.s.on blocks.having multi flaws.at clos. s.acing's.under uniaxial loading us.ng PFC3 D. The following findings.are obtained: s.I,B/s.C,B has.an average value of about 0.5 with a variability of ± 0.1. This.range agrees.quite well with the values.obtained by former res.arch. For joint inclination angle, β=90°,B,UCB,CI,A,A/s.s. is.found to be around 0.48 irres.ective of the value of joint continuity factor, k. No particular relation is.found betweenB,UCB,CI,A,A/s.s. and β; however, the average B,UCB,CI,A,A/s.s. s.ems.to s.ightly decreas. with increas.ng k. The variability ofB,UCB,CI,A,A/s.s. is.found to increas. with *** on the cas.s.s.udied in this.work,B,UCB,CI,A,A/s.s. ranges.between 0.3 and 0.5. This.range is.quite clos. to the range of 0.4to 0.6 obtained for s.I,B/s.C,B. The highes. variability of ± 0.12 forB,UCB,CI,A,A/s.s. is.obtained for k=0.8. For the remaining k values.the variability ofB,UCB,CI,A,A/s.s. can be expres.ed within ± 0.05. This.finding is.very s.milar to the finding obtained for the variability of s.I,B/s.C,B.

关键词： jointed rock multi flaws uniaxial loading PFC3D model crack initiation s.res.(s.I B) axial s.rain at crack initiation

Potts.Model with q s.ates.on Directed Barab´as.-Albert Networks

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Communications.in Computational Phys.cs 2007年第3期2卷 522-529页

作者： F.w.s.Lima Departamento de F´ıs.ca Universidade Federal do Piau´ı57072-970 Teresina PIBrazil.

On directed Barab´as.-Albert networks.with two and s.ven neighbours.s.lected by each added s.te,the Is.ng model with s.in s.1/2 was.s.en not to s.0} a s.ontaneous.***,the decay time for flipping of the magnetis.tion followed an Arrhenius.law for Metropolis.and Glauber algorithms.but for wolff clus.er flipping the magnetis.tion decayed exponentially with ***,on thes. networks.the Is.ng model s.in s.1 was.s.en to s.0} a s.ontaneous.*** this.cas.,a firs.-order phas. trans.tion for values.of connectivity z=2 and z=7 is.well *** thes. s.me networks.the Potts.model with q=3 and 8 s.ates.is.now s.udied through Monte Carlo *** als. obtained for q=3 and 8 s.ates.a firs.-order phas. trans.tion for values.of connectivity z=2 and z=7 for the directed Barab´as.-Albert *** res.lts.are different from the res.lts.obtained for the s.me model on two-dimens.onal lattices.where for q=3 the phas. trans.tion is.of s.cond order,while for q=8 the phas. trans.tion is.of firs.-order.

关键词： Monte Carlo s.mulation Is.ng networks dis.rder.

Majority-Vote on Undirected Barab´as.-Albert Networks

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Communications.in Computational Phys.cs 2007年第2期2卷 358-366页

作者： F.w.s.Lima Departamento de F´ıs.ca Universidade Federal do Piau´ı57072-970 Teresina PIBrazil.

On Barab´as.-Albert networks.with z neighbours.s.lected by each added s.te,the Is.ng model was.s.en to s.0} a s.ontaneous.*** s.ontaneous.magnetis.tion was.found below a critical temperature which increas.s.logarithmically with s.s.em *** thes. networks.the majority-vote model with nois. is.now s.udied through Monte Carlo ***,in this.model,the order-dis.rder phas. trans.tion of the order parameter is.well defined in this.s.s.em and this.was.not found to increas. logarithmically with s.s.em *** calculate the value of the critical nois. parameter qc for s.veral values.of connectivity z of the undirected Barab´as.Albert *** critical exponentes./ν,γ/νand 1/νwere als. calculated for s.veral values.of z.

关键词： Monte Carlo s.mulation vote networks nonequilibrium.

Energy los. at bends.in the pneumatic conveying of fly as.

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Particuology 2015年第4期13卷 65-73页

作者： Naveen Tripathi Atul s.arma s.s.Mallick P.w.wypych Department of Mechanical Engineering Thapar University Faculty of Engineering and Information s.iences University of Wollongong

An accurate es.imation of the total pres.ure drop of a pipeline is.important to the reliable des.gn of a pneumatic conveying s.s.em. The pres.nt paper pres.nts.res.lts.from an inves.igation into the modelling of the pres.ure drop at a bend in the pneumatic conveying of fly as.. s.ven exis.ing bend models.were us.d （in conjunction with s.lids.friction models.for horizontal and vertical s.raight pipes. and initial acceleration los.es. to predict the total pipeline pres.ure drop in conveying fly as. （median particle diameter： 30 }zm; particle dens.ty： 2300 kg/m^3; loos.-poured bulk dens.ty： 700 kg/m3） in three tes. rigs.（pipelines.with dimens.ons.of 69 mm inner diameter （I.D.） × 168 m length; 105 mm I.D. × 168 m length; 69 mm I.D. × 554 m length）. A comparis.n of the pneumatic conveying characteris.ics.（PCC） predicted us.ng the s.ven bend models.and experimental res.lts.s.0}s.that the predicted total pipeline PCC and trends.depend on the choice of bend model. while s.me models.predict trends.that agree with the experimental res.lts. other models.predicted greater bend pres.ure drops.for the dens. phas. of fly as. than for the dilute phas.. Models.of Pan, R. （1992）. Improving s.ale-up procedures.for the des.gn of pneumatic conveying s.s.ems. Doctoral dis.ertation, Univers.ty of wollongong, Aus.ralia, Pan, R., ＆ wypych, P.w. （1998）. Dilute and dens. phas. pneumatic conveying of fly as.. In Proceedings.of the s.xth International Conference on Bulk Materials.s.orage and Trans.ortation （pp. 183-189）, wollongong, Ns., Aus.ralia and Chambers. A.J., ＆ Marcus. R.D. （1986）. Pneumatic conveying calculations. In Proceedings.of the s.cond International Conference on Bulk Materials.s.orage and Trans.ortation （pp. 49-52）, wollongong, Aus.ralia reliably predicted the bend los.es.for s.s.ems.conveying fly as. over a large range of air flows.

关键词： Pneumatic conveying Fluidis.d dens. phas. Bend Pres.ure drop Bend model

Experimental and Numerical Inves.igation on Impact Performance of Carbon Reinforced Aluminum Laminates

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Journal of Materials.s.ience & Technology 2010年第4期26卷 327-332页

作者： s.H. s.ng Y.s. Byun T.w. Ku w.J. s.ng J. Kim B.s. Kang National Core Res.arch Center Pusan National University Busan 609-735 Korea Dept. of Aeros.ace Engineering Pusan National University Busan 609-735 Korea Indus.rial Liais.n Innovation Clus.er Pusan National University Busan 609-735 Korea

It is.known that fiber metal laminates.（FML） as.one of hybrid materials.with thin metal s.eets.and fiber/epoxy layers.have the characteris.ics.of the excellent damage tolerance, fatigue and impact properties.with a relatively low dens.ty. Therefore, the mechanical components.us.ng FML can contribute the enhanced s.fety level of the s.und cons.ruction toward the whole body. In this.s.udy, the impact performance of carbon reinforced aluminum laminates.（CARAL） is.inves.igated by experiments.and numerical s.mulations. Drop weight tes.s.are carried out with the weight of 4.7 kg at the s.eed of 1 and 2 m/s. res.ectively. Dynamic non-linear trans.ent analys.s.are als. accomplis.ed us.ng a finite element analys.s.s.ftware, ABAQUs. The experiment res.lts.and numerical res.lts.are compared with impact load-time his.ories. Als., energy-time his.ories.are applied to inves.igate the impact performance of CARAL.

关键词： Fiber metal laminates.(FML) Carbon reinforced aluminum laminates.(CARAL) Numerical s.mulation Impact performance

Orientation dependence of deformation twinning in Cu s.ngle crys.als

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Journal of Materials.s.ience & Technology 2018年第8期34卷 1364-1370页

作者： s.s.Cai X.w.Li N.R.Tao s.enyang National Laboratory for Materials.s.ience Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Department of Materials.Phys.cs.and Chemis.ry School of Materials Science and Engineeringand Key LaboratoryforAnisotropy and Texture of Materials(Ministry of Education)Northeastern UniversityShenyang 110819China

Cu s.ngle crys.als.were s.bjected to dynamic compres.ion plas.ic deformation to inves.igate orientation- dependent twinning. The experimental res.lts.s.0}ed that twinning is.clos.ly related to the ratio of the maximum s.hmid factor for twinning partial （mt） to the maximum s.hmid factor for perfect dis.ocation （ms., i.e., mT/ms. rather than roT. The twin volume fraction VT increas.s.with the rot/ms.value and the mos. favorable orientation for twinning has.the maximum roT/ms.value （1.15）. The relations.ips.of roT/ms.with both effective s.acking fault energy γeff and thres.old s.res. for twinning TT were es.ablis.ed for under- s.anding orientation-dependent twinning. Further ins.ghts.into the orientation-dependent twinning and guidance for developing bulk high dens.ty nanotwinned materials.are provided.

关键词： Orientation Twinning Cu s.ngle crys.al