学科分类
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500 个结果
  • 简介:我们在aquantum旋转网络的二平行1D旋转链调查纠纷转移,并且证明完美的纠纷转移能在somespecial时间被认识到。另外,“纠纷的现象在thespin被发现的所谓的突然的死亡”网络系统。

  • 标签: 纠缠转移 周期性突然死亡 量子自旋 自旋台链
  • 简介:EXISTENCEOFWEAKSOLUTIONSOF2-DEULEREQUATIONSWITHINITIALVORTICITYω_0∈E(log ̄+L) ̄α(α>0)JIUQUANSEN(InstituteOfAppliedMathematics,t...

  • 标签: EXISTENCE EULER EQUATIONS WEAK SOLUTIONS
  • 简介:酒吧的气质永远是暧昧的粉红,情人节浪漫的约会场所。《风尚player》发扬粉红精神,为情人节的各位们,寻找最具电眼的醒目酒保,再通过秘密的大考验来挑选出TOP10有又有料的酒保。我们的目的只有一个,就是各位大饱眼福的同时,知道哪里有最有并有料的醒目酒保啦!毕竟养眼又能调美酒的酒吧,谁不愿意去呢?

  • 标签: TOP10 酒吧 PLAYER 情人节
  • 简介:<正>新的《数学课程标准(实验稿)》中强调:"教材所选择的素材应尽量来源于自然、社会与科学中的现象和实际问题".因此,以其他学科知识为素材的中考数学题——学科渗透试题,近几年来倍受命题者的关注.所谓学科渗透试题包含两层含义:一是运用数学知识解决其他学科的问题;

  • 标签: 渗透型 命题者 海拔高度 地理知识 课程标准 兴趣小组
  • 简介:3-DevolutionofKarmanvortexfilamentsandvortexfilamentsinbraidregionsintheturbulentwakeofa2-Dcirculaxcylinderisinvestigatednumeri-callybasedoninviscidvortexdynamicsbyanalyzingtheresponseoftheinitially2-Dspanwisevortexfilamentstoperiodicspanwisedisturbanceofvaryingmagnitude,wavelengthandinitialphaseangles.Ourresultsrevealakindof3-Dvortexsysteminthewakewhichconsistsoflargescalehorseshoe-shapedvorticesandsmallscaleλ-shapedvortexfilamentsaswellasvortexloops.Themechanismandthedynamicprocessaboutthegenerationofstreamwisevorticalstructureandthe3-Dcoherentstructurearereported.

  • 标签: THREE-DIMENSIONAL evolution COHERENT structure WAKE flow
  • 简介:Reactionsofthe6-hydroxy-thiopyrano[3,4-c]pyridine-5-carbonitrilederivative1withα-halo-carbonylcompoundsgavetheortho-substitutedintermediates2a-cwhichwereconvertedintofuro[2,3-b]thiopyrano[4,3-d]pyridines3a-cbyfusionofafuranmoietyunderbasicconditions.Furthercyclizationof3a-cledtoafusionofapyrimidinering,yieldingthetetracyclicproducts6,7and8.Inaddition,condensationof6withvariousaromaticaldehydesaffordedthecorrespondingimines9a,b.Mannichreactionof7gaveproducts10a,b.

  • 标签: Synthesis AROMATIC ALDEHYDES products MANNICH reaction
  • 简介:这研究针对使用片3-D优化到在高度的高通过流动扇子/增强软件的角落流动绕过的控制比率广告扇涡轮引擎。二种片3-D优化,弯曲结束并且鞠躬,上被集中。由于各自的操作模式和环境,3-D的途径转子片的空气动力学的建模与定子翼不同。为转子基于角落流动和紧张问题的考虑的机制的理解,这份报纸使用许多片3-D优化途径例如装载分发优化,离开角度的不安和栈轴操作,它分别地对转子和定子合适。获得的3-D片和翼能改进角落流动特征由弯曲结束并且鞠躬效果。流动在扇子/增强软件的角落的这学习表演的结果例如增强软件的翼的扇子中心区域,尖端和中心,由3-D效果很复杂、统治。在那里的第二等的流动被发现在压缩机表演上有强壮的有害效果。效果弯曲结束并且鞠躬能在角落改进流动分离,但是他们工作的特定的方法和申请范围是有点不同的。经由片3-D优化重新设计片控制角落流动有效地减少了损失产生并且由大数量改进了货摊边缘。

  • 标签: 优化控制 流量控制 角落 刀片 风扇 3维
  • 简介:1赛题分析与解题思路2017年美国大学生数学建模竞赛D题研究机场安检系统旅客吞吐量的优化问题。赛题要求针对美国的机场安检系统建立数学模型,解决如下问题:1)研究旅客通过安检系统的流量,并识别现有系统中的瓶颈,找出存在的问题。

  • 标签: 旅客吞吐量 安检系统 优化模型 机场 数学建模竞赛 优化问题
  • 简介:Synthesisofinorganicnanostructureswithspecificsizeandwelldefinedmorphologieshasattractedconsiderableattentionduetotheirsuperiorelectrical,optical,magnetic,andchemical

  • 标签: 纳米结构 FE2O3 合成 笼状 自由 三维
  • 简介:关于递推数列Xn+1=(axn+b)/(cxn+)的极限的注记田文平(南京审计学院)关于递推数列Z.+l一;;=:一的极限.文D」给出了下面两个结论:”—”——“”””“”-x+”“”’””““-“”“““’””“’—””“”结论1设数列?..

  • 标签: 递推数列 极限 充分必要条件 通项公式 线性递归方程 共轭复根
  • 简介:因为graphene和phosphorene,二维(2D)组IV和组V元素的分层的材料引起大兴趣。然而,组IVV单层没收到到期的注意。在这个工作,啜单层的三种类型计算地被设计探索他们的电子结构和光性质。计算证实这些单层的稳定性,它都是有在范围的bandgaps的indirect-bandgap半导体1.382.21eV。bandgaps在pH=跨骑水的氧化还原作用潜力0,用作watersplitting光催化剂显示单层的潜力。计算光性质证明啜2D材料的某些单层是可见的光的吸收器并且将用作optoelectronic设备的好候选人。

  • 标签: 电子结构 光催化剂 单层 2D 可见光 混合物
  • 简介:<正>Westudythenonlineardynamicsoftwo-componentBose-Einsteincondensatesinone-dimensionalpe-riodicopticallatticepotentials.Thestationarystateperturbationsolutionsofthecoupledtwo-componentnonlinearSchr?dinger/Gross-Pitaevskiiequationsareconstructedbyusingthedirectperturbationmethod.Theoreticalanalysisrevelsthattheperturbationsolutionisthechaoticone,whichindicatestheexistenceofchaosandchaoticregioninparameterspace.Thecorrespondingnumericalcalculationresultsagreewellwiththeanalyticalresults.Byapplyingthechaoticperturbationsolution,wedemonstratetheatomicspatialpopulationandtheenergydistributionofthesystemarechaoticgenerally.

  • 标签: STATIONARY state classical chaos TWO-COMPONENT BOSE-EINSTEIN
  • 简介:Two-dimensional(2D)materialshavebeendemonstratedtoexhibituniquepropertiesoriginatingfromits2Dnature.Inrecentyears,theconstructionof2Dmaterialshasbecomeatopicofgreatinterest.Thisarticlesummarizestherecentadvanceof2Dsupramolecularorganicframeworks(SOFs)whicharehomogeneouslyconstructedinsolutionphasethroughself-assemblyofrationallydesignedbuildingblocks.These2DSOFsaresolubleandstillmaintainstablenetworkstructuresinsolutions,whichexhibituniquenessnotonlyinstructuresbutalsoinproperties.Inthisconcisereview,theSOFs-relatedbackgroundisbrieflyintroducedfirstly,followedbyoutliningtheresearchprogressofsoluble2DSOFsfromtheperspectiveofmonomerdesign,assembly,andstructuralcharacterization.Thearticleendswithapersonaloutlookonthefuturedevelopmentofthisnewclassofsupramolecularpolymers.

  • 标签: SUPRAMOLECULAR organic frameworks(SOFs) SELF-ASSEMBLY TWO-DIMENSIONAL SUPRAMOLECULAR
  • 简介:Anewefficientmeshlessmethodbasedontheelement-freeGalerkinmethodisproposedtoanalyzethestaticdeformationofthinandthickplatestructuresinthispaper.Usingthenew3Dshell-likekinematicsinanalogytothesolid-shellconceptofthefiniteelementmethod,discretizationiscarriedoutbythenodeslocatedontheupperandlowersurfacesofthestructures.Theapproximationofallunknownfieldvariablesiscarriedoutbyusingthemovingleastsquares(MLS)approximationschemeinthein-planedirections,whilethelinearinterpolationisappliedthroughthethicknessdirection.Thus,differentboundaryconditionsaredefinedonlyusingdisplacementsandpenaltymethodisusedtoenforcetheessentialboundaryconditions.TheconstrainedGalerkinweakform,whichincorporatesonlydisplacementdegreesoffreedom(d.o.f.s),isderived.Amodified3Dconstitutiverelationshipisadoptedinordertoavoidoreliminatesomeself-lockingeffects.Thenumericefficiencyoftheproposedmeshlessformulationisillustratedbythenumericexamples.

  • 标签: 无网格伽辽金法 三维本构关系 厚板结构 移动最小二乘 边界条件 无网格方法
  • 简介:Fortwo-dimensionnonlinearconvectiondiffusionequation,atwo-gridmethodofcharacteristicsfinite-elementsolutionwasconstructed.Inthismethodthenonlineariterationsisonlytoexecuteonthecoarsegridandthefine-gridsolutioncanbeobtainedinasinglelinearstep.Forthenonlinearconvection-dominateddiffusionequation,thismethodcannotonlystabilizethenumericaloscillationbutalsoacceleratetheconvergenceandimprovethecomputationalefficiency.Theerroranalysisdemonstratesifthemeshsizesbetweencoarse-gridandfine-gridsatisfythecertainrelationship,thetwo-gridsolutionandthecharacteristicsfinite-elementsolutionhavethesameorderofaccuracy.Thenumericalexampleconfirmsthatthetwo-gridmethodismoreefficientthanthatofcharacteristicsfinite-elementmethod.

  • 标签: 有限元分析 非线性传递 扩散方程 迭代法 稳定性
  • 简介:Aself-adaptiveprecisealgorithminthetimedomainwasemployedtosolve2-Dnonlinearcoupledheatandmoisturetransferproblems.Byexpandingvariablesatadiscretizedtimeinterval,thevariationsofvariablescanbedescribedmoreprecisely,andanonlinearcoupledinitialandboundaryvalueproblemwasconvertedintoaseriesofrecurrentlinearboundaryvalueproblemswhicharesolvedbyFEtechnique.Inthecomputation,noadditionalassumptionandthenonlineariterationarerequired,andacriterionforself-adaptivecomputationisproposedtomaintainsufficientcomputingaccuracyforthechangesizesoftimesteps.Inthenumericalcomparison,thevariationsofmaterialpropertieswithtemperature,moisturecontent,andbothtemperatureandmoisturecontentaretakenintoaccount,respectively.Satisfactoryresultshavebeenobtained,indicatingthattheproposedapproachiscapableofdealingwithcomplexnonlinearproblems.

  • 标签: 有限元分析 非线性传输 自适应系统 热量转移 离散特性