简介:Thispaperreportstheexperimentsofevaporationstudyin6mminnercopperdiametertubesusingHFC-134a,HCFC-22andCFC-12asworkingfluid.Theresultsshowthattheevaporationheattransfercofeeicientincreasesewiththedecreasingofinnerdiameteroftubes,AnewconceptofnondimensionaltubediameterUisproposedinthispaperforcorrectionoftheinfluenceofthetubediameterontheevaporationheattransfercoefficient.Andfurther,aconveinentempiricalcorrectionmethodispreseted.
简介:Thispaperstudiesrestrictedfaultdiameterofthen-dimensionalhypercubenetworksQn(n≥2).ItisshownthatforarbitrarytwoverticesxandywiththedistancedinQnandanysetFwithatmost2n-3verticesinQn-{x,y},ifFcontainsneitherofneighbor-setsofxandyinQn,thenthedistancebetweenxandyinQn-FisgivenbyD(Qn-F;x,y){=1,for=1;≤d+4,for2≤d≤n-2,n≥4;≤n+1,ford=n-1,n≥3;=n,ford=n.Furthermore,theupperboundsaretight.Asanimmediatelyconsequence,Qncantolerateupto2n-3verticesfailuresandremaindiameter4ifn=3andn+2ifn≥4providedthatforeachvertexxinQn,alltheneighborsofxdonotfailatthesametime.ThisimprovesEsfahanian'sresult.
简介:让F是有|F的一块地|≥3,李·平·胡昂电子邮件:lipingmath@sohu.com全文预览(小,大)[3]。苍白,Z.X.:重游的矩阵的几何学,代数学和组合数学,一个国际国会,ICAC'97,香港,由K.P编辑了。Shum等,Springer-Verlag,新加坡,1999,477486[4]。黄,L.P.:在任何部门上的hermitian矩阵的毗邻保存bijection地图与复杂物响。ActaMathematicaSinica,英语系列,23(1),95102(2007)[5]。黄,W.L.,Höfer,R.,苍白,Z.X.:毗邻保存地图砰对称并且hermitian矩阵。Aequations数学,67(12),132139(2004)[6]。黄,W.L.,苍白,Z.X.:矩形的矩阵的毗邻保存地图砰。Beiträgezur代数学undGeometrie,45(2),435446(2004)[7]。黄,L.P.:在戒指上的矩阵的几何学,科学出版社,北京,2006[8]。Šemrl,P.:在Hua矩形的矩阵的几何学的基本定理上。J。代数学,248,366380(2002)[9]。Cao,C.G.,黄,L.P.,唐,X.M.:保存在交替的矩阵上的等级2的添加剂地图。Afr。向国外散居J。数学,3(2),107113(2005)[10]。你,H.,唐,X.M.:在对称、交替的矩阵的空格的等级添加的添加剂preservers。线性代数学Appl,380,185198(2004)[11]。张,X.:在在域和应用程序上的交替的矩阵空格的等级的添加剂preservers。线性代数学Appl,397(1),325343(2005)[12]。张,X.:在在地上的交替的矩阵的空格的等级2的Linear/additivepreservers。线性代数学Appl,396(1),91102(2005)[13]。Havlicek,H.,Šemrl,P.:从几何学到invertibilitypreservers。Studia数学,174,99109(2006)
简介:AsubsetofSofthevertexsetofagraphGiscalledacyclicifthesubgraphitinducesinGcontainsnocycles.SiscalledanacyclicdominatingsetofGifitisbothacyclicanddominating.Theminimumcardinalityofanacyclicdominatingset,denotedbyγα(G),iscalledtheacyclicdominationnumberofG.S.M.Hedetniemietal.on2000introducedtheconceptofacyclicdominationandposedthefollowingopenproblem:Isγα(G)≤δ(G)foranygraphwhosediameteristwo?Inthispaper,wegiveacounterexamplewhichdisprovestheproblem.
简介:在这个工作,我们以它的最小的度和它的顺序为任何图的直径获得好上面的界限,改进由于Erd的一条古典定理?s,Pach,绿鳕和Tuza。我们使用这些界限以便学习夸张的图(在Gromov意义)。计算hyperbolicity常数是一个几乎难处理的问题,这样试着以图的一些参数围住它是自然的。让H(n,0)是有n顶点和最小的度0,和J的图G的集合(n,)是有n顶点和最大的度的图G的集合。我们在图上学习四个后面的extremal问题:一(n,0)=min{(G)|GH(n,0)},b(n,0)=最大{(G)|GH(n,0)},(n,)=min{(G)|GJ(n,)}并且(n,)=最大{(G)|GJ(n,)}。特别地,我们为b获得界限(n,0)和我们计算精确价值一(n,0),(n,,并且(),并且(n,)为n的所有价值,0并且分别地。
简介:ThisLetterproposesabrand-newfilamentdiametermeasurementmethodbasedonwhatiscalled'dualdiffraction,'inthatagratingisaddedbehindthefilamenttomakefulluseofitssubdivisionandamplificationcharacteristics.Highermeasurementaccuracyisachievedbythismethodcomparedwiththetraditionaldiffractionmethod.Toverifyitsaccuracy,threestandardfilamentswithnominalvaluesof100.2,120.1,and140.8μmaremeasuredbythedualdiffractionmethodandtraditionaldiffractionmethodunderthesameexperimentalconditions.Therelativemeasurementerrorsofthenewmethodarelessthan0.75%,anditsaveragerelativeerrorisreducedby56%comparedwiththetraditionaldiffractionmethod.
简介:Controlofshockwaveandboundarylayerinteractioncontinuestoattractalotofattention.Inrecentdecadesseveralmethodsofinteractioncontrolhavebeeninvestigated.Theresearchhasmostlyconcernedsolid(vanetype)vortexgeneratorsandtranspirationmethodsofsuctionandblowing.Thisinvestigationconcernsinteractioncontrolusingair-jetstogeneratestreamwisevortices.Theeffectivenessofair-jetvortexgeneratorsincontrollingseparationhasbeenprovedinapreviousresearch.Thepresentpaperfocusesontheinfluenceofthevortexgeneratordiameterontheseparationregion.Itpresentstheresultsofexperimentalinvestigationsandprovidesnewguidelinesforthedesignofair-jetvortexgeneratorstoobtainmoreeffectiveseparationcontrol.
简介:Thelarge-diametercylinderstructure,whichismadeoflargesuccessivebottomlesscylindersplacedonfoundationbedorpartlydrivenintosoil,isarecentlydevelopedretainingstructureinChina.Itcanbeusedinport,coastalandoff-shoreworks.Themethodforstabilityanalysisofthelarge-diametercylinderstructure,especiallyforstabilityanalysisoftheembeddedlarge-diametercylinderstructure,isanimportantissue.Inthispaper,anideaispresentedthatis,em-beddedlarge-diametercylinderquayscanbedividedintotwotypes,i.e.thegravitywalltypeandthecylinderpilewalltype.Amethodforstabilityanalysisofthelarge-diametercylinderquayofthecylinderpilewalltypeisdevelopedandamethodforstabilityanalysisofthelarge-diametercylinderquayofthegravitywalltypeisalsoproposed.Theeffectofsig-nificantparametersonthestabilityofthelarge-dianetercylinderquayofthecylinderpilewalltypeisinvestigatedthroughnumericalcalculation.
简介:High-strengthpipelinesteelandlargediameterlinepipesareoftenusedtoincreasethecapacityoftransportationandreducethecostassociatedwiththeconstructionandoperationoflong-distancegaspipelineprojects.China’sinitiativestoconstructlong-distancenaturalgaspipelineshasbroughtinnewopportunitiesforthedevelopmentofX80linepipes.BaosteelhasdesignedtheoptimumchemicalcompositionofX80withhighniobiumandlowmolybdenumcontent.Inaddition,aweldingexperimentalplatformandafiniteelementmodel(FEM)havesupportedthedevelopmentofX80UOEpipesinanefficientandeconomicalway.TheapplicationandrecentdevelopmentofX80UOEpipeswereintroducedinthispaper.TocomplywiththerequirementsoftheSecondWest-EastGasPipelineProject(2ndWEPP),X80pipelinesteelwithlowcarbonbainitemicrostructurewasdevelopedbyutilizingtheoptimizedcompositionandTMCPprocess.Thematchingweldingmaterial,weldingprocedureandUOEformingprocessesfor1219mmoutsidediameterX80UOEpipeswerealsodeveloped.Morethan340000tofX80UOEpipeswereproducedandappliedinthe2ndWEPP.Furthermore,tomeettheprospectivedemandforlong-distancegaspipelineswithanannualtransportationcapacityofover40billionm3,largersizeX80UOEpipeswith1422mmOD×30.8mmWTweretrialproducedrecently.DWTTperformance,themaintechnicalchallengeforheavierwallpipes,wasimprovedbyusingoptimizedmicrostructuraldesign.ThenewlydevelopedX80pipescanbepotentiallyusedforlargertransportationcapacitypipelinesinChina.
简介:为简单的坑,复杂的坑和盆和价值在海洋之神Procellarum区域附近学习影响坑的深度直径关系证实深入地(付款交丹)的二个变化弯。我们分类影响坑到三种类型,它是简单的坑,复杂的坑和盆。用在数据的最太古或最深的坑,三种深度直径关系是坚定的:线性为简单的坑合适是d=0.126D+0.4902;为复杂的坑合适的最好的实验力量是d=0.3273D0.6252;为盆合适的最好的实验力量是d=0.3004D0.4633在d是的地方,坑和D的深度是坑的直径,两个在公里。为盆的深度直径关系被一个更低的斜坡为复杂的坑比那描绘,证明这词法转变对应于深入地相对它有增加尺寸的直径的影响结构的进一步的减少。这些关系然后能被用来估计任何影响半径的理论深度,能因此被用来在海洋之神Procellarum区域附近估计坑的太古的形状。海洋之神Procellarum的学习将帮助人类进一步了解月亮的起源和进化。
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简介:AmethodofcoupledBEM-FEManalysisfortheelasticspatialstructuresystemispresented.Itcanbeappliedtothecalculationofthestressanddeformationofthelarge-diamatercylinderstructuresystemanditissuitableforsymmetricornon-symmetricstructuresunderthedistributedorconcentratedload.NumericalexamplesshowthattheproposedmethodandcomputerprogramBEFEMarequiteefficientintheanalysisofthelarge-diametercylinderstructureproblemsinoceanengineering.