简介:Anewtypeoffiberopticglucosebiosensorbasedonfluorescencequenchinghasbeendesignedanditspropertieshavebeenstudied.Glucosecanbeoxidizedbyoxygenwhenglucoseoxidaseareusedasthecatalyst,therefore,theconcentrationofglucosecanbemeasuredbydetectingtheconsumptionofoxygen.Forthedetectionofoxygenconcentration,theruthenium(Ⅱ)complex,Ru(bpy)3Cl2,wereusedasthefluorescenceindicatoranditsfluorescencelifetimeweredetectedbylock-intechnology.Thedetectingrangeofthesensoris50-500mg/dlanditsresponsetimeis30seconds,showingthatthiskindofsensorsispossibletobeusedinclinicaldiagnosisanddetection.
简介:Usingmoleculardynamics(MD)methodscombiningwithtwo-stepradiationheatingmodel,themechanismsofablationandthethermodynamicstatesatNisurfaceunderfemtosecondlaserirradiationareinvestigated.Simulationresultsshowthatthemainmechanismsofablationareevaporationandtensilestressesgeneratedinsidethetarget.Thevelocityofstresswaveispredictedtobenearlyequaltosoundvelocity.Theratesofablationatdifferentfluencesobtainedfromsimulationsareingoodagreementwithexperimentaldata.Superheatingphenomenonisalsodiscovered.
简介:Alightpurplishredsapphireisheattreatedinanairtightcrucible.Thesamplechangeslittleincolorafterreceivingheattreatmentat1100°C,butturnstolightblueandblueafterbeingtreatedat1200°Cand1300°C,respectively.Beforeheating,theUV-VISabsorptionspectraofthesamplearedominatedbythe551nmbroadabsorptionbandcontributedbythed-electrontransition~4A_2→~4T_2ofCr~(3+).Afterheating,theUV-VISabsorptionspectraaredominatedbythe563nmbroadabsorptionbandcontributedbytheintervalencechargetransferofFe~(2+)-Ti~(4+).ThexrayphotoelectronspectroscopytestrevealsthattheFe~(2+)andTi~(4+)ioncontentsincreasewithincreasingtemperature.ThesapphirechangingfromlightpurplishredtoblueintheheatingprocessisowingtothefactthattheFe~(2+)andTi~(4+)contentsgrowandtheintervalencechargetransferofFe~(2+)-Ti~(4+)selectivelyabsorbsUV-VISlight.
简介:Mitoxantrone,aclinicallyusefulantitumourantibioticforleukaemiaandbreastcancer,hasreceivedmoreattentions.Inthispaper,theinteractionbetweenmitoxantroneandcalfthymusDNAisinvestigatedbyRamanandfluorescencespectroscopies,andthebindingsiteofmitoxantronetocalfthymusDNAisexplored.TheresultsshowedthatmitoxantroneinteractswithcalfthymusDNAbasesbytheintercalationofanthracyclineintothebasepairplaneofadenine(A)andthymine(T),anditresultsinthedisruptionofthehydrogenbondsbetweencalfthymusDNAbases,andthusthecalfthymusDNAdouble-strandcanbedisruptedintotheB-formDNAdouble-strandsegments.
简介:Nitridatedβ-Ga_2O_3(100)substratewasinvestigatedasthesubstrateforGaNepitaxialgrowth.Theeffectsofnitridationtemperatureandsurfaceroughnessofβ-Ga_2O_3wafersontheformationofGaNwerestudied.Itwasfoundthatthemostoptimizednitridationtemperaturewas900°C,andhexagonalGaNwithpreferredorientationwasproducedonthewell-polishedwafer.Thenitridationmechanismwasalsodiscussed.
简介:Thenonlinearswitchingcharacteristicsoffusedfiberdirectionalcouplerswerestudiedexperimentally.Byusingfemtosecondlaserpulseswithpulsewidthof100fsandwavelengthofabout1550nmfromasystemofTi:sapphirelaserandopticalparametricamplifier(OPA),thenonlinearswitchingpropertiesofanullcoupleranda100%couplerweremeasured.Theexperimentalresultswerecoincidentwiththesimulationsbasedonnonlinearpropagationequationsinfiberbyusingsuper-modetheory.Nonlinearlossinfiberwasalsomeasuredtogettheinjectedpoweratthecoupler.Afterdeductingthenonlinearlossandinputefficiency,thenonlinearswitchingcriticalpeakpowersfora100%andanullfusedcouplerswerecalculatedtobe9410and9440W,respectively.ThenonlinearlossparameterPNinanexpressionofαNL=αP/PNwasobtainedtobePN=0.23W.
简介:Thefeasibilityoffenestrationoperationinmiddleearbonewithpulsedinfraredlaserisevaluated.HealthymaleNewZealandrabbitsinvivoareusedintheexperiment.Middleearmastoidboneofanimalmodeliscompletelyexposedwithconventionalmethods,andthenapulsedCO2laser(10.6μm)andanEr:YAGlaser(2.94μm)areusedtoperformthefenestrationoperation.Diamonddrillisalsousedasacontrolgroup.Thetotaloperationtimeandlightirradiationtimearerecordedandtheopeningefficiencyisassessed.Themorphologicalchangesandthermaldamagearoundtheopeningwindowonthemiddleearboneareexamined.Itisshownthatbothlasersystemsaresuitableforthefenestrationoperationinmiddleearbone,andthisno-touchtechniquehasalotofbenefitscomparedwithtraditionalmethods.Thebleedingduringoperationhasanimportanteffectonoperationtimeandthermalinjuryandneedstobecontrolledefficientlyinfurtherstudy.更多还原
简介:Amaster-slaveconfigurationusedtocontrolthenonlinearbehaviorsarisinginaverticalcavitysurfaceemittinglaser(VCSEL)withstrongexternalopticalfeedbackisestablished.Intermsofbifurcationdiagram,timeandfrequencydomain,theinfluenceofthecontinuousopticalinjectionfromthemasterVCSELonthenonlinearcharacteristicsoftheslaveisinvestigatedtheoretically.Forrelativelyweakinjection,theslavestillkeepsitsintrinsicnonlinearstate.Withincreasingtheinjectionstrength,thesenonlinearbehaviorsevolvetoperiodicfluctuation,andatlastarereplacedbythesteady-state(e.g.thecriticalinjectionparameterforsteady-stateis1.2whenexternalcavity'sreflectivityandlengthare4%and4cm,respectively).Duringthisevolutionthebifurcation-contractionphenomenaarealsoobserved.
简介:InordertoimprovetheopticalpropertiesoftheⅢ-Ⅴlaserdiodes(LDs)bymeansofH_2Splasmapassiva-tiontechnology,H_2SplasmapassivationtreatmentisperformedontheGaAs(110)surface.Theoptimumpassivationconditionsobtainedare60-Wradiofrequency(RF)powerand20-minduration.Sothelasercavitysurfacesaretreatedundertheoptimumpassivationconditions.Consequently,comparedwithun-passivatedlaserswithonlyAR/HR-coatings,thecatastrophicopticaldamage(COD)thresholdvalueofthepassivatedlasersbyH_2Splasmatreatmentisincreasedby33%,whichisalmostthesameasthatof(NH_4)_2S_xtreatment.Andthelife-testexperimenthasdemonstratedthatthispassivationmethodismorestablethan(NH_4)_2S_xsolutionwet-passivatedtreatment.
简介:Anovelno-guidelightpentype3D-coordinatemeasurementsystemwiththreesetsofpositionsensitivedevices(PSDs)torealizeintersectionconvergeinagingisintroduced.Itiscalledasthelightpentypemeasurementsystem,becausethemeasuringheadisshapedasapenwithseverallightsourcesonit.Thestructuredesign,measurementprincipleandexperimentalresultsarepresented.Thetheoreticalanalysisandexperimentalresultsprovethatthissystemhasadvancedfeaturesofsimplestructure,highautomation,andhighaccuracy,andcanbeusedinthemeasurementfieldsofmechanicalmanufacture,robot,auto,aviationandmedicineeffectively.
简介:OpticalmethodsandMTTmethodareusedtocharacterizetheantiproliferationeffectofantitumordrug9-aminoacridine(9AA)withandwithoutsilvernanoparticles.IntracellularsurfaceenhancedRamanscattering(SERS)spectraandfluorescentspectraof9AAindicatetheformof9AAadsorbedonthesurfaceofsilvernanoparticles.AlthoughbothsilvernanoparticlesandantitumordrugcaninhibitthegrowthofHelacells,silvernanoparticlescanslowdowntheantiproliferationeffectonHelacellsatlowconcentrationofantitumordrugs.Ourexperimentalresultssuggestthatsilvernanoparticlesmayserveasslow-releasedrugcarriers,whichisimportantinantitumordrugdelivery.
简介:Usingamicrowavegenerator,chlorinedilutedbyheliumwasdissociatedtochlorineatomsthatsubse-quentlyreactedwithhydrogenazidetoproducetheexcitedstatesofNCl(a1△).Meanwhile,moleculariodinewithcarriergasofheliumreactedwithatomicchlorinetoproduceatomiciodinewhichthenwaspumpedtoexcitedstateofI(2P1/2)byanenergytransferreactionfromNCl(a1△).Inthispaper,thechangesofNCl(a1△)andNCl(bi∑)emissionintensityispresentedwhenI2/HeisintroducedintothestreamofCl/Cl2/He/HN3/NCl(a1△)/NCl(b1∑).ThedependencesofatomiciodineI(2P1/2)onflowratesofgaseswerealsoinvestigated.TheoptimumparametersforI(2P1/2)productionaregiven.