简介:ABanachspaceoperatorsatisfiesgeneralizedRakoevi'sproperty(gw)ifthecomplementofitsuppersemiB-WeylspectruminitsapproximatepointspectrumisthesetofeigenvaluesofTwhichareisolatedinthespectrumofT.Inthisnote,wecharacterizehypecyclicandsupercyclicoperatorssatisfyingtheproperty(gw).
简介:Becausemostpiezoelectricdeviceshaveinterfaceswithfluidinengineering,itisvaluabletostudythecoupledfieldbetweenfluidandpiezoelectricmedia.Asthefundamentalproblem,the3DGreen'sfunctionsforpointforcesandpointchargeloadedinthefluidandpiezoelectricbimaterialsarestudiedinthispaper.Basedonthe3Dgeneralsolutionsexpressedbyharmonicfunctions,weconstructedthesuitableharmonicfunctionswithundeterminedconstantsatfirst.Then,thecouplefieldinthefluidandpiezoelectricbimaterialscanbederivedbysubstitutionofharmonicfunctionsintogeneralsolutions.Theseconstantscanbeobtainedbyvirtueofthecompatibility,boundary,andequilibriumconditions.Atlast,thecharacteristicsoftheelectromechanicalcoupledfieldsareshownbynumericalresults.
简介:我们在场这里周期的oligo(乙烯adipate)的第一合成经由有乙烯乙二醇的adipoyl氯化物的伪高度冲淡冷凝作用反应的s(COEA),和合成相应poly(乙烯adipate)(豌豆)经由COEA的melt聚合。COEA的结构被1H-NMR和MALDI-TOF团大小。器官的底,反应温度和到COEA的收益上的乙烯乙二醇的adipoyl氯化物的比率的效果被学习,并且最佳反应条件被揭示。豌豆,二酸和diol基于半水晶的绿脂肪族的聚酯,被COEA的melt聚合用Ti综合(n-C4H9O)是的4是的催化剂和1,10-decanediol在200点的开始者在上到葡萄牙的语言的BPI在巴西说瞄准它的以后的用法在癌症病人生活测量疼痛的紧张和干扰。方法:BPI-B从原来的位/英寸被开发,用背翻译和委员会评论。背Translatio?
简介:Wavepropagationanalysisforafunctionallygradednanobeamwithrectangularcross-sectionrestingonvisco-Pasternak'sfoundationisstudiedinthispaper.Timoshenko'sbeammodelandnonlocalelasticitytheoryareemployedforformulationoftheproblem.TheequationsofmotionarederivedusingHamilton'sprincipalsbycalculatingkineticenergy,strainenergyandworkduetoviscoelasticfoundation.Theeffectsofvariousparameterssuchaswavenumber,non-homogeneousindex,nonlocalparameterandthreeparametersoffoundationareperformedonthephasevelocityofthenanobeam.Theobtainedresultsindicatethatsomeparameterssuchasnon-homogeneousindex,nonlocalparameterandwavenumberhavesignificanteffectontheresponseofthesystem.
简介:目的:研究P波斜入射下的地基动应力路径,探讨其影响因素和可能变化范围,为进一步研究斜入射地震波作用下场地动力响应奠定理论基础。创新点:1.从数学上证明斜入射P波在任一深度的地基中形成的应力路径在剪应力分量(偏差正应力-水平剪应力)组成的平面中为一个斜椭圆;2.分析了P波入射角、土体泊松比和单位波长深度对斜椭圆应力路径形状与大小的影响。方法:1.基于半无限弹性空间的地震波传播理论,考虑地震波在自由界面的反射,推导土体中任一深度处由P波斜入射产生的动应力,并表示成由剪应力分量组成的平面下的应力路径(公式(9))及该应力路径的特征参数表达式(公式(A12)~(A14));2.通过控制变量法,分析参数敏感性(图7、9、10和12)。结论:1.虽然证实P波斜入射引起的应力路径为斜椭圆形式,但在地基深度、入射波频率和波速的特定组合下,斜椭圆仍可从斜线一直变化到圆形,形式较为多样化;2.P波斜入射角度在30?~60?时引起的动偏应力幅最大,最大可达同等条件下其它入射角产生的动应力幅的2倍以上;3.斜入射角大于45?后,斜椭圆路径形状几乎不随入射角改变,在研究范围内以竖直扁椭圆形为主;4.土体饱和度大于70%时,泊松比的变化对土体斜椭圆路径形状影响不大,但动应力幅随泊松比增大而显著降低。
简介:我们学习配对的状态在一大部分在旋转起来和旋转下面费米子分别地被充满到s-和px-orbital乐队的地方,二部件的费密气体在一个各向异性的二维的光格子装载了的imbalanced。我们由于s和pxorbitals的乐队结构的相对倒置显示出那,在一样上在二费米子之间配对的系统帮助Brillouin地区站在一起,与有限center-of-mass动量为状态导致大稳定的政体,即,Fulde-Ferrell-Larkin-Ovchinnikov(FFLO)状态。特别地,二费密什么时候出现,在动量空间是靠近的,嵌套的效果与空间调整稳定-FFLO阶段的一种特殊类型沿着容易掘的x方向。我们在二维的飞机以内为各种各样的方面比率在吝啬地的途径以内畴划零温度的阶段图并且计算Berezinskii-Kosterlitz-Thouless(BKT)转变温度T为不同阶段的BKT。
简介:为了解决乘波体偏离设计条件下气动特性会恶化,特别在低速时,升力严重不足这个问题,提出了通过增大后掠角生成前缘涡,增加背风面的升力,以改善乘波体低速气动性能.首先使用VisualBasic编程语言,并通过CATIA软件二次开发技术,实现了锥导乘波体的参数化设计和自动生成.再通过控制圆锥角和流场长度这两个设计参数,获得了大后掠乘波体构型.最后,运用剪切应力输运(shear-stress-transport,SST)模型,计算了所得乘波体的气动特性,并分析了流场变化,发现乘波体在设计状态下激波能很好附着在前缘上,在小的正攻角下,乘波体可获得比设计状态更高的升阻比,满足巡航要求.运用I.模型计算了乘波体的低速气动特性,得到了不同攻角下升力、阻力和升阻比的变化规律.研究结果发现,乘波体在低速下产生了明显的涡结构,在合适攻角下,能产生数量可观的附加升力,提高了乘波体的水平起降性能.
简介:Althoughmanyliteratureshavebeenfocusedontheunderneathflowandlossmechanism,veryfewexperimentsandsimulationshavebeendoneundertheengines'representativeworkingconditionsorconsideringtherealcavitystructureasawhole.Thispaperaimsatrealizingthegoalofdesignofefficientturbineandscrutinizingthevelocitydistributioninthevicinityoftherimseal.Withtheaidofnumericalmethod,anumericalmodeldescribingtheflowpatternbothinthepurgeflowspotandwithinthemainstreamflowpathisestablished,fluidmigrationanditsaccompaniedflowmechanismwithintherealisticcavitystructure(withrimsealstructureandconsideringmainstream&secondaryairflow'sinteraction)isusedtoevaluateboththeflowpatternandtheunderneathflowmechanismwithintheinwardrotatingcavity.Meanwhile,theunderneathflowandlossmechanismarealsostudiedinthecurrentpaper.Thecomputationalresultsshowthatthesealingairflow'singestionandejectionarehighlyinterwoundwitheachotherinbothupstreamanddownstreamflowoftherimseal.Boththedownstreamblades'potentialeffectsaswellastheupstreamblades'waketrajectorycanbringabouttheingestionofthehotgasflowwithinthecavity,abruptincreaseofthestaticpressureisbelievedtobethemainreason.Also,theresultsindicatethatsealingairflowejectedthroughtherearcavitywillcauseunexpectedlossneartheoutletsectionofthebladesinthedownstreamoftheHProtorpassages.