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  • 简介:在这份报纸,我们与不可压缩的条件为3DMHD方程的答案考虑整齐标准。由使用一些古典不平等,我们分别地以速度地和磁场的一个部件在某些足够的条件下面获得三维的MHD方程的强壮的答案的整齐。

  • 标签: MHD方程 三维 标准 压缩条件 充分条件 组成部分
  • 简介:Inthispaper,twoalgorithmsarepresentedforgeneratingtwocodescanlistsofanN-dimensionalHilbertcell,andaformalproofofthebackwardencodingalgorithmisgiven.Onthebasisoftheself-simi-laritypropertiesofaHilbertcurve,thispapergivesanovelalgorithmforgeneratingastaticevolvementruletablethroughanalyzingaHilbertcell.Bylookingupthestaticevolvementruletable,theN-dimensionalHilbertmappingsareefficientlyimplemented.

  • 标签: 空间图像 图像处理 曲线 地图 编制方法
  • 简介:M(J,{msns},{cs})bethecollectionofCartesianproductsoftwohomogenousMoransetswiththesameratios{cs}whereJ=[0,1]×[0,1].ThenthemaximalandminimalvaluesoftheHausdorffdimensionsfortheelementsinMareobtainedwithoutanyrestrictionon{msns}or{cs}.

  • 标签: 齐次MORAN集 笛卡尔积 尺寸 HAUSDORFF 笛卡尔乘积 最小值
  • 简介:Afinite-ratemethodisusedtosimulatethethree-dimensionalcombustionprocessinaplasmageneratorwithCH4asthefuel.ThesimulationwasrunwithRNGk-εmodeltosimulateturbulence,witheddy-dissipation-concept(EDC)modeltosimulatethecombustionandwithdiscreteordinatesmodeltosimulateradiation.Thenumericalresultsshowthattheflowfieldcharacteristicsandtheparameterdistributionsareundertheconditionofrichfuels,andtheseresultsprovidevaluableinformationwhenoptimizingtheplasmageneratordesignandorganizingitsflowfields.

  • 标签: 燃气轮机 数值模拟 三维模型 等离子体 维修方法
  • 简介:MostalgorithmsoftheimmersedboundarymethodoriginatedbyPeskinareexplicitwhenitcomestothecomputationoftheelasticforcesexertedbytheimmersedboundarytothefluid.Adrawbackofsuchanexplicitapproachisasevererestrictiononthetimestepsizeformaintainingnumericalstability.AnimplicitimmersedboundarymethodintwodimensionsusingthelatticeBoltzmannapproachhasbeenproposed.Thispaperreportsanextensionofthemethodtothreedimensionsanditsapplicationtosimul...

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  • 简介:SufficientconditionsaregiventoassertthattwoC1-mappingsshareonlyonevalueinaconnectedcompactBanachmanifoldmodelledoverRn.Theproofoftheresult,whichisbaseduponcontinuationmethods,isconstructive.

  • 标签: BANACH流形 价值 有限维 充分条件 映象
  • 简介:Thedynamicbehavioroftwo-dimensionalnanostructuresisimportanttothefutureapplicationofnanodevices.Thevibrationalbehaviorsofsingle-layeredhexagonalboronnitride(h-BN)arestudiedbymoleculardynamicssimulationandcontinuumplatemodel.ThebendingstiffnessandPoisson'sratiosofh-BNalongzigzagdirectionandarmchairdirectionarecalculated.H-BNissoftercomparedwithgraphene.Thecontinuumplatemodelcanpredictthevibrationofh-BNwithfouredge-clampedboundaryconditionswell.Theelectricfieldsindifferentdirectionshaveobviousinfluenceonthevibrationofh-BN.Thenaturalfrequencyofh-BNchangeslinearlywiththeelectricfieldintensityalongthepolarizationdirection.Thenaturalfrequencyofh-BNdecreaseswiththeincreaseofelectricfieldintensityalongbothpositiveandnegativenonpolarizationdirection.Whilethenaturalfrequencyofh-BNincreaseswiththeincreaseofelectricfieldintensityalongbothpositiveandnegativetransverseelectricfield.

  • 标签: HEXAGONAL BORON NITRIDE Molecular dynamics Natural
  • 简介:Considerathree-dimensionalsystemhavinganinvariantsurface.Byusingbifurcationtechniquesandanalyzingthesolutionsofbifurcationequations,theauthorsstudythespacialbifurcationphenomenaofakmultipleclosedorbitintheinvariantsurface.Thesufficientconditionsoftheexistenceofmanyclosedorbitsbifurcatefromthekmultipleclosedorbitareobtained.

  • 标签: 表面变化 闭合周期轨道 三维系统 分支方程 线性代数
  • 简介:Inthispaperwestudytheexistence,pathwiseuniquenessandhomeomorphismflowofstrongsolutionstoaclassofonedimensionalSDEsdrivenbyinfinitelymanyBrownianmotions,andwithYamada-Watanabediffusioncoefficientsanddistributionaldriftcoefficients.

  • 标签: 随机微分 方程式 漂移 同拓扑
  • 简介:BackgroundTwo-dimensionalspeckletrackingimaging(2D-STI)andreal-timethree-dimensionalechocardiography(RT-3DE)havemoreadvantagesinevaluatingleftventricular(LV)systolicdyssynchronythantraditionalechocardiographictechniques.ThestudyaimedtoevaluateLVdyssynchronyparametersbyboth2D-STIandRT-3DE,andthecorrelationbetweenthesetwotechniques.MethodsAtotalof43chronicheartfailure(CHF)patientsand27healthyvolunteerswereenrolled.Therewere23dyssynchronyparametersselectedtoevaluateleftventricularsystolicsynchronization,involving15from2D-STIand8fromRT-3DE.ResultsFewofthedyssynchronyparametersshowednegativecorrelationswithLVejectionfraction(LVEF)intheCHFgroup.Thedifferencebetweentimetopeak-systolicradialstrainoftheanteroseptalandposteriorsegmentsatthelevelofpapillarymuscles[AS-P(RS)]from2D-STIshowedpositivecorrelationswithpartsoftheparametersfromRT-3DE(P<0.05).ConclusionsLVsystolicdysfunctiondoesnotcorrelatewithdyssynchrony.Moreover,thereisaweakassociationbetween2D-STIandRT-3DEinassessmentofleftventriculardyssynchrony.

  • 标签: 超声心动图 成像技术 收缩功能 同步性 左心室 评价
  • 简介:Thefundamentalmomentumconservationrequirementq~0fortheRamanprocessisrelaxedinthenanocrystallites(NCs),andphononsawayfromtheBrillouin-zonecenterwillbeinvolvedintheRamanscattering,whichiswell-knownasthephononconfinementeffectinNCs.ThisusuallygivesadownshiftandasymmetricbroadeningoftheRamanpeakinvariousNCs.Recently,theA'_1modeof1LMoS2NCsisfoundtoexhibitablueshiftandasymmetricbroadeningtowardthehigh-frequencyside[Chem.Soc.Rev.44(2015)2757andPhys.Rev.B91(2015)195411].Inthiswork,wecarefullycheckthisissuebystudyingRamanspectraof1LMoS2NCspreparedbytheionimplantationtechniqueinawiderangeofion-implanteddosage.ThesameconfinementcoefficientisusedforbothE'andA'_1modesin1LMoS_2NCssincethephononuncertaintyinanNCismainlydeterminedbyitsdomainsize.TheasymmetricalbroadeningneartheA′_1andE′modesisattributedtotheappearanceofdefect-activatedphononsatthezoneedgeandtheintrinsicasymmetricalbroadeningofthetwomodes,wheretheanisotropyofphonondispersioncurvesalongΓ-KandΓ-Misalsoconsidered.Thephotoluminescencespectraconfirmtheformationofsmalldomainsizeof1LMoS_2nanocrystallitesintheion-implanted1LMoS_2.Thisstudyprovidesnotonlyanapproachtoquicklyprobephonondispersiontrendsof2DmaterialsawayfromΓbytheRamanscatteringofthecorrespondingNCs,butalsoareferencetocompletelyunderstandtheconfinementeffectofdifferentmodesinvariousnanomaterials.

  • 标签: 声子色散 MOS2 布里渊区 纳米探针 二维材料 离子注入技术
  • 简介:该研究采用传统热压和喷蒸热压两种方法来生产杨木刨花板.刨花板内施加10%的脲醛树脂胶(UF),目标厚度分别取10,15,20,和25mm,热压温度均为180℃.喷蒸热压时饱和蒸汽的压力为0.3~0.5MPa,每种厚度下喷汽时间一定,取两个热压时间;传统热压时每种厚度下各取4个热压时间.然后测定试件的吸水厚度膨胀率、吸水率、密度、含水率及力学性能.本文重点讨论了喷蒸热压对杨木刨花板尺寸稳定性的影响.结论认为:喷蒸热压相对于传统热压,在保证刨花板的强度、缩短热压时间的条件下,明显改善了杨木刨花板的尺寸稳定性.

  • 标签: 喷蒸热压 传统热压 杨木刨花板 尺寸稳定性
  • 简介:Thisstudypresentsthenumericalresultsforthethree-dimensionalnaturalgas-airmixinginarectangularsubsonicchannelunderthestandarddatumstate.ThelowerandupperdecompositionmethodwasemployedtoobtainthesolutionsofthefullNavier-Stokesequationscapableofdescribingcompressiblefluidmixing.Gridwasgeneratedbytheareaorthogonaltechnique.Theresultsindicatethatthree-dimensionalmixingbetweenNaturalGas(NG)andairhasmorecomplicatedcompressiblewavesaroundtheinjectionnozzle.Thepresenceofinjectionwithlargespeedcansuppresstheboundaryseparationhappenedoccurringatthetopwallduetothechannelexpansion,butmakesthenear-wakeflowmorecomplicated.Themixingregioncanbewidenedbyincreasingtheinjectionspeed.TherecurrenceofthevortexstructureandthecoherentstructurecanbefoundfromthefullNavier-Stokessimulation.ItcanbeconcludedthattheincreaseintheinjectionvelocitycanimprovetheeffectivenessofmixingofNGandairinthenearwakeoftheinjectors.

  • 标签: 燃料空气混合 LU分解 数值模拟 Navier-Stokes流体方程
  • 简介:Heattransportisakeyenergeticprocessinmaterialsanddevices.Thereducedsamplesize,lowdimensionoftheproblemandtherichspectrumofmaterialimperfectionsintroducefruitfulphenomenaatnanoscale.Inthisreview,wesummarizerecentprogressesintheunderstandingofheattransportprocessinlow-dimensionalmaterials,withfocusontherolesofdefects,disorder,interfaces,andthequantummechanicaleffect.Newphysicsuncoveredfromcomputationalsimulations,experimentalstudies,andpredictablemodelswillbereviewed,followedbyaperspectiveonopenchallenges.

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  • 简介:作者在非各向同性的海森堡组和海森堡类型组织的二种更高维的海森堡组鈥?为热核获得锋利的坡度估计吗?n,m。这里使用的方法在光线的功能和一些联系semigroup技术上依靠Bakry-茅mery弯曲螕2的积极性质。关键词坡度估计-螕2弯曲-加热核-Sublaplace-海森堡组2000苏布杰克特先生分类58J35-中国奖学金委员会(号码2007U13020)支持的43A80工程。

  • 标签: 海森堡群 梯度估计 高维 非各向同性 径向函数 F2代
  • 简介:AbstractBackground:Hemifacial microsomia (HFM), which involves multiple sites with different levels of severity, is the second most common congenital craniofacial deformity after cleft lip and palate. However, three-dimensional (3D) measurements of mandibular deformities have not yet been studied in detail. The objective of this study is to investigate the method of 3D measurements of mandibular deformities in HFM patients.Methods:A total of 48 HFM patients were included in this study. All clinical treatment for patients was performed in the Plastic Surgery Hospital of the Chinese Academy of Medical Sciences at Peking Union Medical College from June 2006 to June 2020. The patients’ 3D computerized tomography scan data were processed using medical imaging software, following four iterative steps: 3D reconstruction, mirroring, differential analysis, and partition.Results:The characteristics of the mandibular bone in HFM patients are mainly presented as follows: (1) compared to the normal side, the part of the bone body that extends from the ascending ramus to the pogonion (Po-NB) is analyzed using a dynamic process: less fullness-fullness-more fullness; (2) absences were frequently observed among the angular zones, that is, the height of the ascending ramus is deficient.Conclusions:HFM is a complicated condition with numerous variations in clinical presentation. We employed both 3D image reconstruction and computerization image processing techniques to investigate asymmetrical mandibular deformity in HFM patients in detail and with great accuracy. This will be of great use to clinicians for disease management.

  • 标签: Hemifacial microsomia Mandibular deformity Three-dimensional measurement