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:Moleculardynamics(MD)simulationsareperformedtostudyadhesionandpeelingofashortfragmentofsinglestrandDNA(ssDNA)moleculefromagraphitesurface.Thecriticalpeel-offforceisfoundtodependonboththepeelingangleandtheelasticityofssDNA.FortheshortssDNAstrandunderinvestigation,weshowthatthesimulationresultscanbeexplainedbyacontinuummodelofanadhesiveelasticbandonsubstrate.Theanalysissuggeststhatitisoftenthepeakvalue,ratherthanthemeanvalue,ofadhesionenergywhichdeterminesthepeelingofananoscalematerial.
简介:Wehaveinvestigatedthephysicalproperties,includingthemorphology,texture,adhesionandchemicalquality,ofhigh-frequencychemicalvapourdepositeddiamondcoatingsonWC-6%Cosubstrates,whichwerepre-treatedbyatwo-stepetchingmethod.TheresultsindicatethattheincreasingCocontentfrom0.12to3.05%withintheetchingdepthof5μmcausedamorphologytransformationfromprismdiamondtospheruliticdiamond,andatexturetransformationfroma{111}orientationtoa{110}orientation.TheRamanspectrumshowsthatthespheruliticdiamondfilmcontainsmorenon-diamondphases(graphite,amorphouscarbonanddiamond-likecarbon,etc)andhaslowerchemicalqualitythandiamondfilmsonaWC-6%Cosubstrate.Thediamondcoatinggrainsizesbecameaboutfourtimessmallerwhenthedepositiontemperaturesonthesubstratesurfacewerereducedfrom1000to900℃.Comparedwithspheruliticdiamondfilms,theprismdiamondfilmsexhibitbetteradhesionontheWC-6%Cosubstrate.
简介:Tetrahedralamorphoushydrogenatedcarbon(ta-C:H)filmsonSi(lO0)substrateswerepreparedbyusingamagnetic-field-filterplasmastreamdepositionsystem.Sampleswithdifferentratiosofsp^3-bondtosp^2-bondwereobtainedbychangingthebiasvoltageappliedtothesubstrates.Theellipsometricspectraofvariouscarbonfilmsinthephotonenergyrangeof1.9-5.4eVweremeasured.Therefractiveindexnandtherelativesp^3CratioofthesefilmswereobtainedbysimulatingtheirellipsometricspectrausingtheForouhi-BloomermodelandbyusingtheBruggemaneffectivemediumapproximation,respectively.Thehaemocompatibilityoftheseta-C:Hfilmswasanalysedbyobservationofplateletadhesionandmeasurementofkineticclottingtime.Theresultsshowthatthesp^3Cfractionisdependentonthesubstratebiasvoltage,andthehaemocompatibilityisdependentontheratioofsp^3-bondtosp^2-bond.Agoodhaemocompatibilitymaterialofta-C:Hfilmswithasuitablesp^3Cfractioncanbepreparedbychangingthesubstratebiasvoltage.
简介:Afullsolutionoftwo-dimensionalNavier-Stokesandenergyequationwasconductednumericallytoanalyzethenaturalconvectionofthehorizontalstripwithanadiabaticsubstrate.Themainfeaturesofsuchconvectionare:(i)theleadingandtrailingedgeeffect,(ii)thenon-boundarylayereffect,and(iii)thesideedgeeffect.Theresultsarecomparedwiththeboundarylayertheoryandexprimentaldata.
简介:ThescatteringofLovewavesbyaninterfacecrackbetweenapiezoelectriclayerandanelas-ticsubstrateisinvestigatedbyusingtheintegraltransformandsingularintegralequationtechniques.Thedy-namicstressintensityfactorsoftheleftandtherightcracktipsaredetermined.Itisfoundfromnumericalcalculationthatthedynamicresponseofthesystemdependssignificantlyonthecrackconfiguration,thema-terialcombinationandthepropagatingdirectionoftheincidentwave.Itisexpectedthatspecifyinganappro-priatematerialcombinationmayretardthegrowthofthecrackforacertaincrackconfiguration.
简介:Wehavefabricatedatop-emittingorganiclight-emittingdeviceonsiliconsubstratewithhighyellowluminancebasedon5,6,11,12-tetraphenylnaphthacenesub-monolayer.Itconsistsofathinlayerofhighlyconductivesilverasthesemitransparentcathodeandsurfaced-modifiedAgastheanode.Thedeviceturnsonat3Vwiththeluminanceof8.4cd/m^2.Themaximumcurrentefficiencyis1.3cd/Aat6Vandtheluminancereaches14790cd/m^2at14V.Theperformanceofthedeviceisexcellentintop-emittingorganiclight-emittingdevicesaccordingtoourknowledge.
简介:WereportonN-dopedp-typeZnOfilmswiththec-axisparalleltothesubstrate.ZnOfilmswerepreparedonana-Al2O3(0001)substratebysolid-sourcechemicalvapourdeposition(CVD),Zn(CH3COO)2.2H2OwasusedastheprecursorandCH3COONH4asthenitrogensource.Thegrowthtemperaturewasvariedfrom300℃to600℃,theas-grownZnOfilmdepositedat500℃showedp-typeconductionwithitsresistivityof42Ωcm,carrierdensity3.7×10^17cm^-3andHallmobility1.26cm^2V^-1.s^-1atroomtemperature,whicharethebestpropertiesforp-typeZnOdepositedbyCVD.Thep-typeZnOfilmpossessesatransmittanceofabout85%inthevisibleregionandabandgapof3.21eVatroomtemperature.