学科分类
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6 个结果
  • 简介:Low-lyingstatesofaverticallycoupledthree-layerquantum-dotsystemarestudied.Eachlayercontainsoneelectron,andthetunnellingofelectronsbetweenlayersisneglected.EffectsoftheinterlayerseparationdandtheexternalmagneticfieldBareevaluatedbynumericalcalculations.Inthestrongcouplingcase(i.e.dissmall),asinasingledot,transitionsoftheangularmomentumLofthetruegroundstatesoccurwhenBincreases,whereasintheweakcouplingcasethetransitiondoesnotoccurandLremainszero.Furthermore,itisfoundthatthevariationofdmayalsoinducetheLtransition.Asaresult,aphasediagramofLofthetruegroundstateisgiveninthed-Bplane.

  • 标签: 半导体 半导体异质结构 三层量子斑点 半导体量子理论
  • 简介:Thispaperpresentsawaytomeasurethetruetemperatureoftheelectronicdeviceswithoutdisturbingtheirnormaloperatingconditions,whichinvolvedwithestimatingtargetemissivity,backgroundtemperaturecorrectlyandchoosinginfraredtransparentmaterialanditstransmissionestimation.Thetemperaturedistributionsofthemainboardinpersonalcomputerweremeasuredbythemethodpresentedherewithinfraredthermographyinseveraldifferentrunningconditions.Themeasurementerrorsandtheirpossibleremediesarealsodiscussed.

  • 标签: INFRARED THERMOGRAPHY ELECTRONIC COOLING TEMPERATURE distrubution
  • 简介:Areasonablestrengthcriterionshouldreflectthehydrostaticpressureeffect,minimumprincipalstresseffect,andintermediateprincipalstresseffect.Theformertwoeffectscanbedescribedbythemeridiancurves,andthelastonemainlydependsontheLodeangledependencefunction.Amongthreeconventionalstrengthcriteria,i.e.Mohr–Coulomb(MC),Hoek–Brown(HB),andExponent(EP)criteria,thedifferencebetweengeneralizedcompressionandextensionstrengthofEPcriterionexperienceafirstlyincreasethendecreaseprocess,andtendstobezerowhenhydrostaticpressureisbigenough.Thisisinaccordancewithintrinsicrockstrengthcharacterization.Moreover,thecriticalhydrostaticpressureIccorrespondingtothemaximumdifferenceofbetweengeneralizedcompressionandextensionstrengthcanbeeasilyadjustedbyminimumprincipalstressinfluenceparameterK.So,theexponentfunctionisamorereasonablemeridiancurves,whichwellreflectsthehydrostaticpressureeffectandisemployedtodescribethegeneralizedcompressionandextensionstrength.Meanwhile,threeLodeangledependencefunctionsofLMN,LWW,andLYMH,whichunconditionallysatisfytheconvexityanddifferentialrequirements,areemployedtorepresenttheintermediateprincipalstresseffect.Realizingtheactualstrengthsurfaceshouldbelocatedbetweenthegeneralizedcompressionandextensionsurface,newtrue-triaxialcriteriaareproposedbycombiningthetwostatesofEPcriterionbyLodeangledependencefunctionwithasamelodeangle.Theproposednewtrue-triaxialcriteriahavethesamestrengthparametersasEPcriterion.Finally,14groupsoftriaxialtestdataareemployedtovalidatetheproposedcriteria.Theresultsshowthatthethreenewtrue-triaxialexponentcriteria,especiallytheExponentWillam-Warnkecriterion(EPWW)criterion,givemuchlowermisfits,whichillustratesthattheEPcriterionandLWWhavemorereasonablemeridiananddeviatoricfunctionform,respectively.Theproposednewtrue-tria

  • 标签: Rock Strength criterion MERIDIAN plane Lode
  • 简介:AgraphGiscalledchromatic-choosableifitschoicenumberisequaltoitschromaticnumber,namelych(G)=χ(G).Ohba’sconjecturestatesthateverygraphGwith2χ(G)+1orfewerverticesischromaticchoosable.ItisclearthatOhba’sconjectureistrueifandonlyifitistrueforcompletemultipartitegraphs.Recently,Kostochka,StiebitzandWoodallshowedthatOhba’sconjectureholdsforcompletemultipartitegraphswithpartitesizeatmostfive.Butthecompletemultipartitegraphswithnorestrictionontheirpartitesize,forwhichOhba’sconjecturehasbeenverifiedarenothingmorethanthegraphsKt+3,2*(k-t-1),1*tbyEnotomoetal.,andKt+2,3,2*(k-t-2),1*tfort≤4byShenetal..Inthispaper,usingtheconceptoff-choosable(orL0-size-choosable)ofgraphs,weshowthatOhba’sconjectureisalsotrueforthegraphsKt+2,3,2*(k-t-2),1*twhent≥5.Thus,Ohba’sconjectureistrueforgraphsKt+2,3,2*(k-t-2),1*tforallintegerst≥1.

  • 标签: 猜想 完全多部图 可选择 时间 KT 色数