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I.IntroductionItisaveryinlportulltdiscoveryofcoherentstrLICturcinshetlrturbulellt11owsbyexperimentinthelate1950s,whichleadsustoseekthenaturall,ropertiesofturbulcllcefromthenewideaandilladifferentway.ThestudyofthecoherclltstrLlcttlrcisofgreatimportallcetounderstandthegeneration,developmentanddecayof'tLlrbulellce,allditlsoconstructsInorerealisticturbulencemodeltheory.Meanwhile,itwillbeor11elpIYomengineerillgpoint,suchaslllassandheattrallslbr,dl'agI.eductiolland11oisecontrolproblems.Soinlnlel… 相似文献
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古志鸣 《应用数学和力学(英文版)》1998,19(10):991-996
1.IntroductionWeestimatedthenumberofthetypesofthesmalloscillatiolls11eal'theequilibriunlpositionsillthewholeconfigurationspace.Theanaliysisofsmalloscillationisbasedonthelillearizationofthesysteminaneighborhoodofanequilibriumposition.Butitisnotavailabletarthelarge-scaleperiodicmotionstolinearizethesystem.Inthispuper,we'llestimatethenumberofthetypesoflarge-scaleperiodicmotionsoftheHamiltonsystembymeansofthetopologicalpropertiesofthephasespaceandthehamiltonian.Ourtoolsare11omologygrd'upsandtheM… 相似文献
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I.IntroductionThenearwallcoherentstructureinaturbulentboundarylayer11aslongbeenthesubjectforalarge11umberofinvestigations.Thereisnolongeranydoubtthatcoherentstructuresareamajorcompollentinwall-boundedturbulentshearflows.Theyplayanimportantroleintheproduction,dissipationandtransportationofturbulentenergy.Oneofthenumerousdifficultiesofthesestudiesishowtoquantitativelymeasurecoherentstructurefromphysicalexperimentsorfi.omdirectnumericalsimulations.Thegoalistoisolateorcharacterizethecoherentstruc… 相似文献
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戴天民 《应用数学和力学(英文版)》1997,18(10):921-925
ProJeclstIpportedb}theNdtionalNaturalSciel1ceFoundationofChinaandtheRearchFoundalio11olLiao11inRPI-()\'111ccI.IntroductionGuohaspresentedi11hismonographl']5variousmomentumequations,i.e.,momentumequationsofCauch}),Boussinesq.KirchhoffSignoriniandNowozilov,… 相似文献
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李刚常 《应用数学和力学(英文版)》1998,19(2):135-146
I.IntroductionSinceE.T.Whittaker.proposedfoestabilit}'problellll'lofnonholononlicsystemsin1904forthefirsttime,thescholarsathomeandabroad11a\'emadealotofresearchesontheequilibriunlstabilityoflinearand11olllinearnonllolollolnicsystems,andhaveobtainedaseriesofimportantresultslZ--7].Hobbled'er,theexpositionandapplicationrelatedtoLagrange'stheorenlinthestabilityanalysisfornonholonomicsystemsisseldonlseenuptonow.Althoughitwasmentionedinreference[3].aspecialdiscussionhasnotbeencarriedoutyet.Asafam… 相似文献
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沈敏 《应用数学和力学(英文版)》1998,19(10):963-969
I.IntroductionTileresearchworkonvariationalprincipleinhydrodynamicsstartedasearlyas1940's.Referencesl:~6]aretheoneswhichmakemoreimportantcolltributions.l-lowevcr,mostoftheseworksstudied11on-viscousflow,putemphasisontheproblemsofexternalllcld,andworkedontilebasisofBernoulli'sequation.Prot'essorChienWeizang11I.slesttlblishcdvariationalprincipleforhydrodynalllicpl-oblemofviscousfluid,thatistheprillciplcofmaxilnLllllpowerlosses,alldgeneralizedvariational(stationary)pl.inciplesoiltilebiLsisofNav… 相似文献
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Numerical research on the coherent structure in the viscoelastic second-order mixing layers 总被引:3,自引:0,他引:3
I.IntroductionViscoelastict'olwsareprevalentinstiring,mixingandchemicalreactionofdilutepolymersolutions.SinceTomsdiscoveredthedragreducingeffectofpolylllerudditivesontul.bulent11owsin1948,1llilnystudiesonitsmechanisms11acebeendoneinviewofitsenormouspr'tcticillalld[lleorcticill\'al[Ics.UPtodata,1ilorcasonilbicilltcrl,rclilti')lls,II()wcvcr,ill'cstillun'lvtlilabjedLlctotiledilllcultiesillfoeviscoelasticdyllalnicsalldthetLlrbulellcetllcory.Al'cwpolymericadditiveshavinglittleeffectonthesolvent… 相似文献
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B. K. Sharma B. S. Thakur 《应用数学和力学(英文版)》1997,18(8):771-778
I.IntroductionTheconceptofasymptoticregularitywasintroducedbyBrowderandPetryshynl'].LetEbearealBanachspacewithnorn11l'l'AmappingT:E-Eissaidtobeasymptotical1yregulariflimijT" 'x~T'x:l=ofora1lxinE,whereTffxdenotesthenthiteratio11of--ooT.ltiswell-knownthatif… 相似文献
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Iterative solution of nonlinear equations with strongly accretive operators in Banach spaces 总被引:1,自引:0,他引:1
周海云 《应用数学和力学(英文版)》1999,20(3):282-289
1IntroductionandPreliminariesLetXbearealBanachspacewithnormIJ'11andadualX'.ThenormalizeddualitymappingJ:X~ZxisdefinedbyJx={x'eX*I(x,x')=11x112=11x if'},where',')denotesthegeneralizeddualitypairing.Itiswell-knownthatifX isstrictlyconvex,Jissingle-valuedandJ(tx)=tjxforallt201xeX.IfX*isuniformlyconvex,thenJisuniformlycontinuousonanyboundedsubsetSofX(of.Browde,fljandBarbuL2]).AnoperatorTwithdomainD(T)andrangeR(T)inXissaidtobeaccretiveifforeveryx,y6D(T),thereexistsajeJ(x--y)suchthat(T… 相似文献
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Nonlinear deformation theory of thin shell 总被引:3,自引:0,他引:3
IntroductionThenonlineardeformationproblemofthinshellisaverycomplexanddifficultproblem.Itmustbesimplified.Inreferencebook,forexample,tosimplifyχ=α233α231 α232 α233-1,usuallyputtingα231 α232 α233=1[1],wegetχ=α233-1.Whenα33>1,wegetχ>0.Moreovertosimplifyε11=(1 e11)2 e212 e213-1,whene11,e212,e21… 相似文献
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热弹性通解完备性的一个新证明 总被引:5,自引:1,他引:5
关于线性各向同性热弹性问题,M.A.Biot提供了一个通解表达式,A.Verruijt证明了这个通解式的完备性。但是此证明十分冗长.本文提供一个完备性证明,这个证明比[2]的证明要简明得多. 相似文献
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从探究物理机制的视角对混凝土疲劳研究进行了逻辑上的梳理,表明既有研究可分为3 类主要模型:基于疲劳试验分析的现象学模型、基于断裂力学的疲劳裂纹扩展模型和基于损伤力学的疲劳损伤演化模型. 通过解析具有典型性的研究,论述了不同类型研究的特点. 进而,从还原论的角度出发,阐明了速率过程理论可以作为解释混凝土材料疲劳损伤演化的物理基础. 注意到疲劳试验结果所表现出的显著随机性,阐述了应以物理随机系统思想研究混凝土疲劳问题的观点. 相似文献
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In response to the need in industry for a quick and reproducible method of measuring the flowability of powders in processes involving transport and storage, the apparently simple idea of measuring angle of repose has been revived. The simple tester first used has evolved over a number of years into the present version which is shown to be capable of handling quite small samples of powders that are even slightly cohesive. Experimental data are presented and results shown to compare consistently with the better known Hausner ratio. 相似文献
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本文研究了几种简单的浮体和船体模型的稳定性,并对船体模型能承受的最大外力矩作了分析和计算,然后将这些分析和计算方法推广到任意形状的实际船体。这对船舶设计提供了一定的参考。本文对浮体稳定平衡的6种判据作了比较,指出各自的优点和局限性,以及相互关系。这对澄清有关的基本概念,改进该领域的教学和研究,会有所助益。 相似文献
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D. Geldart E. C. Abdullah A. Hassanpour L. C. Nwoke I. Wouters 《中国颗粒学报》2006,4(3):104-107
In response to the need in industry for a quick and reproducible method of measuring the flowability of powders in processes involving transport and storage, the apparently simple idea of measuring angle of repose has been revived. The simple tester first used has evolved over a number of years into the present version which is shown to be capable of handling quite small samples of powders that are even slightly cohesive. Experimental data are presented and results shown to compare consistently with the better known Hausner ratio. 相似文献
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本文研究数学规划加权残值法在非线性微分方程求解中的应用,利用数学规划加权残值法和LP模理论,把非线性微分方程边值问题转化为一个可微分的无约束非线性优化问题,从而运用成熟稳定的寻优方法求得问题的解。文中数字计算例子表明本文方法可以快速有效地求解非线性微分方程。 相似文献