简介:Poly4-vinylphenol(P4VP)/multi-wallcarbonnanotubes(MWNTs)multi-layersensitivefilmsweredepositedoninterdigitatedelectrodesbyairbrushtechnologytodetecttoluenevaporatroomtemperature.Thesurfaceandsectionmorphologiesofthemulti-layerfilmswereobservedbyascanningelectronmicroscope(SEM).Itisfoundthattheresistanceofthesensorincreaseswhenitisexposedtotoluenevaporandtheresponsehasagoodlinearitywiththeconcentrationoftoluene.TheresultsshowthattheP4VP/MWNTsthree-layerfilmsensorshavebettersensingpropertiescomparedwiththetwo-layerfilmsensors.Therelatedsensingmechanismisstudiedindetail.
简介:Theformaldehyde(HCHO)detectingatroomtemperatureisofgreatsignificance.DifferentratiosofP3HT/ZnOcompositefilms(3:1,1:1,and1:3)weredepositedontheorganicthinfilmtransistor(OTFT)byspray-depositiontechnology,andtheelectricalpropertiesandHCHO-sensingpropertiesofallthepreparedOTFTdevicesweremeasuredbyKeithley4200-SCSsourcemeasurementunit.TheresultsshowthattheOTFTsensorbasedontheP3HT/ZnOfilmswiththeratioof1:1exhibitedthebestoutputandtransfercurves.DifferentchangingtendencywereobservedwiththeincreaseofZnOproportionwhenexposedtoHCHOatroomtemperature,andthedevicewiththeratioof1:1behavedagoodresponseandrecoverycharacteristics.
简介:Thestabilityofthedrivecurrentisveryimportantforalaserdriver,whileitisdifficulttomaintainthecurrentstableatahighvalueforthelaserdriver.Ontheotherhand,therangeofthedrivecurrentisexpectedtobeaswideaspossibletobeappliedtodifferentkindsoflasers.Inthispaper,ahighcurrentlaserdriverforthesuperluminescentlightemittingdiode(SLED)ispresented,whichisusedintheopticfibergyroembeddedbya0.35mbipolarcomplementarymetal-oxide-semiconductortransistor(BiCMOS)process.Thelaserdriverprovidesautomaticpowercontrolandcertainvalueofcurrentdeterminedbytheexternalresister.Thesystemisbasedontheoptic-electricfeedbacktheoryandusestheclosed-loopcontroltechniquetomaintainthedrivecurrentstable.Thesystemiscapableofproducingstablecurrentrangesfrom4mAto200mAwhenthevalueofexternalresisterchanges.