学科分类
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32 个结果
  • 简介:Thispaperaimstogivesomeexamplesofdiffeomorphic(orhomeomorphic)lowdimensionalcompleteintersections,whichcanbeconsideredasageometricalrealizationofclassificationtheoremsaboutcompleteintersections.AconjectureofLibgoberandWood(1982)willbeconfirmedbyoneoftheexamples.

  • 标签: 交叉口 几何 低维 微分同胚 分类定理 相交
  • 简介:Heattransportisakeyenergeticprocessinmaterialsanddevices.Thereducedsamplesize,lowdimensionoftheproblemandtherichspectrumofmaterialimperfectionsintroducefruitfulphenomenaatnanoscale.Inthisreview,wesummarizerecentprogressesintheunderstandingofheattransportprocessinlow-dimensionalmaterials,withfocusontherolesofdefects,disorder,interfaces,andthequantummechanicaleffect.Newphysicsuncoveredfromcomputationalsimulations,experimentalstudies,andpredictablemodelswillbereviewed,followedbyaperspectiveonopenchallenges.

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  • 简介:Duetotheupcomingdemandsofnext-generationelectronic/magnetoelectronicdeviceswithlow-energyconsumption,emergingcorrelatedmaterials(suchassuperconductors,topologicalinsulatorsandmanganites)areoneofthehighlypromisingcandidatesfortheapplications.Forthepastdecades,manganiteshaveattractedgreatinterestduetothecolossalmagnetoresistanceeffect,charge-spin-orbitalordering,andelectronicphaseseparation.However,theincapableofdeterministiccontrolofthoseemerginglow-dimensionalspinstructuresatambientconditionrestricttheirpossibleapplications.Therefore,theunderstandingandcontrolofthedynamicbehaviorsofspinorderparametersatnanoscaleinmanganitesunderexternalstimuliwithlowenergyconsumption,especiallyatroomtemperatureishighlydesired.Inthisreview,wecollectedrecentmajorprogressesofnanoscalecontrolofspinstructuresinmanganitesatlowdimension,especiallyfocusingonthecontroloftheirphaseboundaries,domainwallsaswellasthetopologicalspinstructures(e.g.,skyrmions).Inaddition,capacitor-basedprototypespintronicdevicesareproposedbytakingadvantageoftheabovecontrolmethodsinmanganites.Thiscapacitor-basedstructuremayprovideanewplatformforthedesignoffuturespintronicdeviceswithlow-energyconsumption.

  • 标签: 自旋结构 定性控制 锰氧化物 低维材料 纳米级 磁电子器件
  • 简介:Farr-Gao算法是为减少的Gr的一个最先进的算法?bner有限的点的消失的理想基于,它作为一个内建的命令在枫树被实现了。这份报纸为它论述二维的改进那为计算减少的Gr采用预处理策略?与给定的点集合的塔子集联系的bner底。试验性的结果证明preprocessedFarr-Gao算法比古典的更有效。

  • 标签: Gr ? bner 基础 Gr ? bner
  • 简介:Anticipatedbackwardstochasticdifferentialequation(ABSDE)studiedthefirsttimein2007isanewtypeofstochasticdifferentialequations.Inthispaper,weestablishageneralcomparisontheoremforABSDEs.

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  • 简介:ExperimentsontheNationalIgnitionFacilityshowthatmulti-dimensionaleffectscurrentlydominatetheimplosionperformance.Lowmodeimplosionsymmetryandhydrodynamicinstabilitiesseededbycapsulemountingfeaturesappeartobetwokeylimitingfactorsforimplosionperformance.Onereasonthesefactorshavealargeimpactontheperformanceofinertialconfinementfusionimplosionsisthehighconvergencerequiredtoachievehighfusiongains.Totackletheseproblems,apredictableimplosionplatformisneededmeaningexperimentsmusttrade-offhighgainforperformance.LANLhasadoptedthreemainapproachestodevelopaone-dimensional(1D)implosionplatformwhere1Dmeansmeasuredyieldoverthe1Dcleancalculation.Ahighadiabat,lowconvergenceplatformisbeingdevelopedusingberylliumcapsulesenablinglargercase-to-capsuleratiostoimprovesymmetry.Thesecondapproachisliquidfuellayersusingwettedfoamtargets.Withliquidfuellayers,theimplosionconvergencecanbecontrolledviatheinitialvaporpressuresetbythetargetfieldingtemperature.Thelastmethodisdoubleshelltargets.Fordoubleshells,thesmallerinnershellhousestheDTfuelandtheconvergenceofthiscavityisrelativelysmallcomparedtohotspotignition.However,doubleshelltargetshaveadifferentsetoftrade-offversusadvantages.Detailsforeachoftheseapproachesaredescribed.

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  • 简介:Wepresentaninexpensivetechniquetoobtainathree-dimensional(3D)millimeterwave(MMW)andterahertz(THz)imageusingupconversion.InthisworkwedescribeanddemonstrateamethodforupconversionofMMW/THzradiationtothevisualbandusingaveryinexpensiveminiatureglowdischargedetector(GDD)andasiliconphotodetector.WepresentMMW/THzupconversionimagesbasedonmeasuringthevisuallightemittingfromtheGDDratherthanitselectricalcurrent.Theresultsshowbetterresponsetimeandbettersensitivitycomparedtotheelectronicdetectionperformedpreviously.Furthermore,inthisworkweperformfrequencymodulationcontinuouswave(FMCW)radardetectionbasedonthismethodusingaGDDlamp,withaphotodetectortomeasureGDDlightemission.ByusingFMCWdetection,therangeinadditiontotheintensityateachpixelcanbeobtained,thusyieldingthe3Dimage.TheGDDactsasaheterodynemixernotonlyelectronicallybutalsooptically.Thesuggested3DupconversiontechniqueusingtheGDDissimpleandinexpensiveandhasbetterperformancecomparedtootherMMW/THzimagingsystemssuggestedintheliterature.Thismethodprovidesminimumdetectablesignalpowerthatisabout6ordersofmagnitudebetterthansimilarplasmasystemsduetotheverylargeinternalsignalgainderivingfromthemuchsmallerelectrodeseparationandresultinginmuchhigherplasmaelectricfield.

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  • 简介:Three-dimensional(3D)printing(3DP)isarapidprototypingtechnologythathasgainedincreasingrecognitioninmanydifferentfields.Inherentaccuracyandlow-costpropertyenableapplicabilityof3DPinmanyareas,suchasmanufacturing,aerospace,medical,andindustrialdesign.Recently,3DPhasgainedconsiderableattentioninthemedicalfield.Theimagedatacanbequicklyturnedintophysicalobjectsbyusing3DPtechnology.Theseobjectsarebeingusedacrossavarietyofsurgicalspecialties.Theshortageofcadaverspecimensisamajorprobleminmedicaleducation.However,thisconcernhasbeensolvedwiththeemergenceof3DPmodel.Custom-madeitemscanbeproducedbyusing3DPtechnology.Thisinnovationallows3DPuseinpreoperativeplanningandsurgicaltraining.Learningisdifficultamongmedicalstudentsbecauseofthecomplexanatomicalstructuresoftheliver.Thus,3Dvisualizationisausefultoolinanatomyteachingandhepaticsurgicaltraining.However,conventionalmodelsdonotcapturehapticqualities.3DPcanproducehighlyaccurateandcomplexphysicalmodels.Manytypesofhumanoranimaldifferentiatedcellscanbeprintedsuccessfullywiththedevelopmentof3Dbio-printingtechnology.Thisprogressrepresentsavaluablebreakthroughthatexhibitsmanypotentialuses,suchasresearchondrugmetabolismorliverdiseasemechanism.Thistechnologycanalsobeusedtosolveshortageoforgansfortransplantinthefuture.

  • 标签: 肝脏疾病 三维印刷 医学领域 外科 快速成型技术 应用
  • 简介:轧了nanorods被磁控管劈啪作响和加氨系统综合,并且Tb中间的层的厚度被改变学习效果在上轧了nanorods。结果被扫描电子测试显微镜学(SEM),X光检查衍射(XRD),传播电子显微镜学(TEM),高分辨率的传播电子显微镜学(HRTEM),和光致发光(PL)系列。结果证明Tb层的厚度在形式,质量,和光性质上有明显的效果轧了nanorods。在房间温度的PL系列在368点显示出一座很强壮的排放山峰?nm和弱排出物在387点达到顶点?当Tb层是20时,为生产样品的山峰的nm,和紧张到达最大值?nm。最后,20的最佳的厚度?为综合的Tb中间的层的nm轧了nanostructures被完成。

  • 标签: GAN纳米棒 中间层 高分辨透射电子显微镜 厚度 TB 合成
  • 简介:Theinstabilityofterahertz(THz)plasmawavesintwo-dimensional(2D)quantumelectrongasinananometerfieldeffecttransistor(FET)withasymmetricalboundaryconditionshasbeeninvestigated.WeanalyzeTHzplasmawavesoftwopartsofthe2Dquantumelectrongas:gatedandungatedregions.Theresultsshowthattheradiationfrequencyandtheincrement(radiationpower)in2Dungatedquantumelectrongasaremuchhigherthanthatin2Dgatedquantumelectrongas.Thequantumeffectsalwaysenhancetheradiationpowerandenlargetheregionofinstabilityinbothcases.Thisallowsustoconcludethat2Dquantumelectrongasinthetransistorchannelisimportantfortheemissionanddetectionprocessandbothgatedandungatedpartstakepartinthatprocess.

  • 标签: 二维电子气 等离子体波 量子效应 不稳定性 太赫兹 门控
  • 简介:Inthispaper,weusecontractionmappingprinciple,operator-theoreticapproachandsomeuniformestimatestoestablishlocalsolvabilityoftheparabolic-hyperbolictypechemotaxissystemwithfixedboundaryin1-dimensionaldomain.Inaddition,localsolvabilityofthefreeboundaryproblemisconsideredbystraighteningthefreeboundary.

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  • 简介:Inthispaper,thethree-dimensional(3D)couplingeffectisdiscussedfornanowirejunctionlesssilicon-on-insulator(SOI)FinFETs.Withfinwidthdecreasingfrom100nmto7nm,theelectricfieldinducedbythelateralgatesincreasesandthereforetheinfluenceofbackgateonthethresholdvoltageweakens.Foranarrowandtallfin,thelateralgatesmainlycontrolthechannelandthereforetheeffectofbackgatedecreases.Asimpletwo-dimensional(2D)potentialmodelisproposedforthesubthresholdregionofjunctionlessSOIFinFET.TCADsimulationsvalidateourmodel.Itcanbeusedtoextractthethresholdvoltageanddopingconcentration.Inaddition,thetuningofbackgateonthethresholdvoltagecanbepredicted.

  • 标签: FINFET 模型分析 耦合效应 SOI 纳米线 三维
  • 简介:Inthispaper,bifurcationofsmallamplitudelimitcyclesfromthedegenerateequilibriumofathree-dimensionalsystemisinvestigated.Firstly,themethodtocalculatethefocalvaluesatnilpotentcriticalpointoncentermanifoldisdiscussed.Thenanexampleisstudied,bycomputingthequasi-Lyapunovconstants,theexistenceofatleast4limitcyclesonthecentermanifoldisproved.Intermsofdegeneratesingularityinhigh-dimensionalsystems,ourworkisnew.

  • 标签: 极限环分支 三维系统 Lyapunov 复性 中心流形 高维系统
  • 简介:空气隔板提供安全、干净、适当的空气流动给引擎并且广泛地与象轮船和潜水艇那样的大引擎在车辆被使用。在这运作的研究,在清洗的一个Ranque-Hilsch旋涡试管内的分离进程(冷却)系统被调查在旋涡试管性能上分析操作煤气的类型的影响;使用的操作气体是空气,氮,氧,二氧化碳和氮二氧化物。动态模型使用了的计算液体与三维的结构被装备,并且不变的条件在计算期间被使用。标准k-骚乱模特儿被雇用解决非线性的流动方程,和各种各样的关键参数,例如热、冷用尽热落下,并且驱动分离率,数字地被描述。结果证明氮二氧化物创造最大的分离从测试的所有气体的力量,和数字结果被对可得到的试验性的数据的好同意验证。另外,比较在二个不同边界条件,pressure-far-field和压力插头的使用之间被做,当在空气隔板内分析复杂狂暴的流动时。结果在未来为使用介绍一个全面、实际的答案数字研究。

  • 标签: 分离过程 数值研究 三维结构 涡流管 空气分离器 流体动力学模型
  • 简介:一个三维的数字模型在现在的纸被开发,旨在模仿处于不连续的状况的推迟的沉积运输。在模型,推迟的沉积的移流散开方程基于未组织的网孔用紧缩的不连续的Galerkin(CDG)方法被解决。模型的评估揭示了在建议模型和存在理论之间的好同意。模型有秒顺序精确性。而且,模型被用于引起由的推迟的沉积运输的一个理想化的盒子基于这块地撕破水流空间规模。

  • 标签: 三维模型 悬移质输沙 紧凑型 有限元法 间断 GALERKIN解
  • 简介:多层的沙岩水库全球性发生并且当前在国际生产。这些水库的3D特征太复杂,不能被一般structural-facies-reservoir建模精确地描出。鉴于特殊地质的特征,例如沙岩和mudstoneinterbeds的垂直建筑学,侧面的稳定的沉积和水库poroperm和液体分发的强壮的异质,我们为多层的沙岩水库的3D描述开发了一个新三阶段、六阶段的过程。过程包括二阶段的结构的建模,二阶段的外形建模和水库性质的二种类型的建模。用这个过程,我们建立了形成的模型结构,沙身体结构和microfacies,水库外形和性质包括孔,渗透和煤气的浸透并且提供了3DSebei多层的沙岩气体地的好规模的、系统的描述,中国。这个新过程,由Sebei煤气的地验证了,能被使用描绘类似的多层的沙岩水库。

  • 标签: 砂岩油藏 三维模型 涩北气田 中国 储层沉积相 储层模型
  • 简介:Thispaperisconcernedwithasingularlimitfortheone-dimensionalcompressibleradiationhydrodynamicsmodel.ThesingularlimitweconsidercorrespondstothephysicalproblemoflettingtheBouguernumberinfinitewhilekeepingtheBoltzmannnumberconstant.InthecasewhenthecorrespondingEulersystemadmitsacontactdiscontinuitywave,WangandXie(2011)[12]recentlyverifiedthissingularlimitandprovedthatthesolutionofthecompressibleradiationhydrodynamicsmodelconvergestothestrongcontactdiscontinuitywaveintheL∞-normawayfromthediscontinuitylineatarateofε14,asthereciprocaloftheBouguernumbertendstozero.Inthispaper,WangandXie’sconvergencerateisimprovedtoε7/8byintroducinganewaprioriassumptionandsomerefinedenergyestimates.Moreover,itisshownthattheradiationfluxqtendstozerointheL∞-normawayfromthediscontinuityline,ataconvergencerateasthereciprocaloftheBouguernumbertendstozero.

  • 标签: 流体力学模型 收敛速度 辐射通量 可压缩 一维 接触面
  • 简介:Twodifferentmethodsfromgraphicprocessingunit(GPU)andcentralprocessingunit(CPU)areproposedtosuitablyoptimizelook-uptablealgorithmsofcomputergeneratedholography(CGH).Thenumericalsimulationsandexperimentalresultsshowthatwecanreconstructagoodqualityobject.ThecomputationofCGHforathree-dimensional(3D)dynamicholographicdisplaycanalsobespedupbyprogrammingwithourproposedmethod.Itcanoptimizebothfileloadingandtheinlinecalculationprocess.Thephase-onlyCGHwithgigabytedataforreconstructing10MBobjectsamplingsisgenerated.Inaddition,theproposedmethodeffectivelyreducedtimecostsofloadingandwritingofflinetablesonaCPU.ItisbelievedtheproposedmethodcanprovidehighspeedandhugedataCGHfor3Ddynamicholographicdisplaysinthenearfuture.

  • 标签: 全息显示 三维动态 字节 计算机 计算全息图 中央处理单元
  • 简介:Inthispaper,themodifiedextendedtanhmethodisusedtoconstructmoregeneralexactsolutionsofa(2+1)-dimensionalnonlinearSchr¨odingerequation.WiththeaidofMapleandMatlabsoftware,weobtainexactexplicitkinkwavesolutions,peakonwavesolutions,periodicwavesolutionsandtheir3Dimages.

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