简介:Thisstudyconcernsatwo-dimensionalmodelandthecorrespondingvirtualcrackclosuretechnique(VCCT)implementedtosolvethegeneralboundaryvalueproblemsthatmayexplainwhyinterfacediscontinuityhaseffectsonthefracturebehaviorinthesuperconductor-substratesystem.Theinterfacialdiscontinuitycanbeclassifiedaccordingtothematerialproperties'continuityandtheirderivatives'continuityattheinterface.Fornonhomogeneoussuperconductorandsubstratespecimenswithvariousmaterialproperties,aVCCTmethodisdevelopedtocalculatetheirfracturebehavior.Furthermore,theeffectsofappliedmagneticfieldamplitudeandnonhomogeneousparametersareextensivelyandparametricallystudiedintwoactivationprocesses(zero-fieldcoolingandfieldcooling).Theintegrativeandcomputationalstudypresentedhereprovideafundamentalmechanisticunderstandingofthefracturemechanisminthesuperconductor-substratesystemandshedslightontherationaldesignofinterfacialcontinuity.
简介:Theglobalresearchofsuper-conductorshasbeenprevailingsincethediscoveryofrareearthoxidesuperconductingmaterialin1986.InChina,withtheco-effortsofallrelatedinstitu-tions,theresearchinthisfieldhaspercolatedintomanybranchesincludingphysics,chemistry,materialscience,electrotechnicsandelectronics.Asoneknows,thecriticalcurrentdensityisoneofthemostimportantindexesinsuper-conductors,andthatofYBaCuO
简介:Consideringthatinamagneticresonancesystem,ifthedetectioncoilcontributesdominantlytothesystemnoise,theperformanceofthewholesystemcancertainlybeimprovedbyswitchingtoadetectioncoilmadeofahigh-temperaturesuperconductor,andusingYBa2Cu3O7thinfilmson25×25mm^2LaAlO3substrates,wehavepreparedtwokindsofdetectioncoils:single-coilandtwo-coil.encouragingly,theirqualityfactorsaremeasuredtobeQ>2500fortwo-coil(at22.566MHzand77K)andQ>5500forsingle-coil(at92.3MHzand77K),respectively,Here,wedescribethedetailsofthedesign,fabricationandtestingofthecoils.
简介:Thenovelideathatspin-orbitcoupling(SOC)andans-wavepairingsystemcanleadtoinducedpwavepairingwithastrongmagneticlimit,hasstimulatedwidespreadinterestinsearchingforMajoranafermions(MFs)insemiconductor-superconductorhybridstructures.However,despitemajoradvancesinthesemiconductornanotechnology,thissystemhasseveralinherentlimitationsthatprohibittherealizationandidentificationofMFs.Weovercometheselimitationsbyreplacingthes-wavesuperconductorwiththetype-IIFulde-Ferrell(FF)superconductor,inwhichthecenter-of-massmomentumoftheCooperpairrenormalizesthein-planeZeemanfieldandchemicalpotential.Asaresult,MFscanberealizedinsemiconductornanowireswithsmallvaluesoftheLandég-factorandhighcarrierdensities.TheSOCstrengthdirectlyinfluencesthetopologicalboundary;thus,thetopologicalphasetransitionandassociatedMFscanbeengineeredbyanexternalelectricfield.Theoretically,almostallsemiconductornanowirescanbeusedtorealizeMFsbyusingtheFFsuperconductor.However,wefindthatInPnanowireismoresuitablefortherealizationofMFscomparedtoInAsandInSbnanowires.Thus,thisnewschemecantakefulladvantageofthesemiconductornanotechnologyfortherealizationofMFsinsemiconductor-superconductorhybridstructures.
简介:ThetunnelingspectrumofanelectronandaholeinasuperlattieeofNSjunctionsiscomputedusingtheBTKapproachandthetransfermatrixmethod.Itshowssharpresonancesatsomeenergiesabovethesuperconductinggap.Thesharpertheresonanceisthemorelayersthesuperlatticehas.Wefindforthefirsttimeamechanismtobalancetheincidentandoutgoingcurrentsonthesuperlatticebyaveragingoverthephasebetweentheincidentelectronandtheincidenthole.Thismechanismismorenaturalandphysicalthanthoseinliteratures.
简介:Amethodhasbeendevisedtoanalyzemultilayerelectricallythickcircularmi-crostripantennaexcitedbyaprobe.Thecurrentontheprobeistakentobeuniform.Thismethodwasverifiedbyanalysisandexperimentofanelectricallythickcircularmicrostripan-tennawithanairgap.BasedonthefreespaceelectricdyadicGreen’sfunction,thefieldexpressionofanhorizontalelectricdipole(HED),whichislocatedatanypointofthemultilayermediaandpointsinanydirection,hasbeenderived.ByusingthisfieldexpressionandtheRichmondre-actionequation,anintegralequationintermsofelectriccurrentonthepatchisformulated.Byproperlychoosingcurrentexpansionmodes,thismethodcanbeusedforanelectricallythickmi-crostripantenna.Thetheoreticalresultsagreeverywellwithexperimentaldataforanelectricallythickcircularmicrostripantennawithanairgap.
简介:ThepurecubicGaN(c-GaN)hasbeengrownon(001)GaAssubstratesbyECR-PAMOCVDtechniqueatlowtemperatureusingTMGaandhighpureN2asGaandNsources,respectively.TheeffectsofsubstratepretreatmentconditionsonqualityofcubicGaNepilayerareinvestigatedbythemeasurementsofTEMandXRD.Itisfoundthathydrogenplasmacleaning,nitridationandbufferlayergrowthareveryimportantforqualityofcubicGaNepilayer.
简介:Moleculardynamics(MD)simulationsareperformedtostudyadhesionandpeelingofashortfragmentofsinglestrandDNA(ssDNA)moleculefromagraphitesurface.Thecriticalpeel-offforceisfoundtodependonboththepeelingangleandtheelasticityofssDNA.FortheshortssDNAstrandunderinvestigation,weshowthatthesimulationresultscanbeexplainedbyacontinuummodelofanadhesiveelasticbandonsubstrate.Theanalysissuggeststhatitisoftenthepeakvalue,ratherthanthemeanvalue,ofadhesionenergywhichdeterminesthepeelingofananoscalematerial.
简介:TheheterogeneousnucleationbehaviorsofNH4ClcrystalonroughaluminumsubstratesurfaceimmergedinNH4Cl-H2Osolutionwereexperimentallyanalyzed,andtheinfluencemechanismofthemicro/nano-scalesurfacestructuresonheterogeneousnucleationwasinvestigated.Ithasbeenshownthatwettabilityandnucleationareaffectedbysubstratesurfacecondition.Theintrinsicwettingpropertiesbetweennucleusandsubstratesurface,andthesurfacestructureofcertaingeometricalscales,bothimposeeffectsontheheterogeneousnucleationproperties.Foranucleus-wettingsubstratesurface,heterogeneousnucleationispromotedbyahighercomplexityofthesurfacemorphology;butforanucleus-nonwettingsubstratesurface,heterogeneousnucleationisinhibitedbyahighercomplexityofthesurfacemorphology.
简介:TheheterogeneousnucleationbehaviorsofNH4ClcrystalonaroughchillingsurfaceofaluminumimmergedinNH4Cl-H2Osolutionwereexperimentallyanalyzedandtherelationshipbetweenthesurfaceroughnessandthenucleationsiteselectionbehaviorsonpolishedaluminumsubstratewasinvestigated,anditwasdiscoveredthatthenumberofnucleationsitesdecreasessignificantlywithdecreasingtheroughnessofthepolishedsubstrate.Furthernucleationexperimentswerecarriedoutonchemicallyetchedaluminumsubstratewithregularmicro-morphologyonitssurface.Ithasbeenshownthatboththemicro-morphologyandthewettabilityvarywiththesubstratesurfacepreparedbydifferentetchingprocess.Thepreparedsurfacewithstep-likestructureshasastrongwettabilitywithNH4Cl-70wt%H2OsolutionandthenucleationdensityofNH4Clontheitssurfacesissignificantlyhigherthanthatofthereferencesurfaces,whichshowsthatthegeometricalmorphologyfeatureshaveimportanteffectsonboththewettabilityandthenucleationbehaviors.
简介:Electronicsystemswithlargestretchabilityhavemanyapplications.Apreciselycontrolledbucklingstrategytoincreasethestretchabilityhasbeendemonstratedbycombininglithographicallypatternedsurfacebondingchemistryandabucklingprocess.Thebuckledgeometrywasassumedtohaveasinusoidalform,whichmayresultinerrorstodeterminethestrainsinthefilm.Atheoreticalmodelispresentedinthislettertostudythemechanicsofthistypeofthinfilm/substratesystembydiscardingtheass...