简介:Aconstructionmethodbasedonthep-planetodesignhigh-girthquasi-cycliclow-densityparity-check(QC-LDPC)codesisproposed.Firstlythegoodpointsineverylineofthep-planecanbeascertainedthroughfilteringthebadpoints,becausethedesignedparity-checkmatrixesusingthesepointshavetheshortcyclesinTannergraphofcodes.Thenoneofthebestpointsfromtheresidualgoodpointsofeverylineinthep-planewillbefound,respectively.Theoptimalpointisalsosingledoutaccordingtothebiterrorrate(BER)performanceoftheQC-LDPCcodesatlast.ExplicitnecessaryandsufficientconditionsfortheQC-LDPCcodestohavenoshortcyclesarepresentedwhichareinfavorofremovingthebadpointsinthep-plane.Sincepreventingtheshortcyclesalsopreventsthesmallstoppingsets,theproposedconstructionmethodalsoleadstoQC-LDPCcodeswithahigherstoppingdistance.
简介:ByanalyzingthemainrecombinationmechanismsinGaInAsSbmaterials,thedependencesofthedarkcurrentdensityandopencircuitvoltageinn+-pGaInAsSbthermophotovoltaiccellsontherecombinationparameters,carrierconcentrationandcellthicknessarecalculated.Theresultsshowthatthedarkcurrentmainlycomesfromp-region,anditisrelatedwiththesurfaceandAugerrecombinationsinlowandhighcarrierconcentrationranges,respectively.ThesurfaceandAugerrecombinationscanbesuppressedbyreducingthesurfacerecombinationvelocityandcarrierconcentration,respectively.Thedarkcurrentdensitycanbesuppressedbyoptimizingmaterialparametersanddevicesurfacepassivationtechnique.SothehighopencircuitvoltagecanbeobtainedforGaInAsSbthermophotovoltaiccells.
简介:回想去年年来的手机市场,以索尼爱立信P908.摩托罗拉A768.多普达696等为主的智能手机着实火了一把,也让手机在功能方面进行了一次洗礼。那时候也有很多人认为智能手机会在今年大红大紫,成为当然的主流。然而.手机在功能方面虽然一直在发展.但却衍生出拍照手机商务手机.娱乐手机等不同的形态.在过去意义上的综合性能的智能手机新品却并不多见。作为摩托罗拉A768和索尼爱立信P908的升级作品,摩托罗拉A780和索尼爱立信P910c这两款智能手机终于在年底和人们见面了,同时出现在手机市场的选两款重量级作品到底有什么独到之处?这里就向大家一一进行展示。
简介:Inthelaserwarningsystem,anon-mechanicalscanningFabry-Perot(F-P)typelaserwarningmethodanditscrucialcomponent-laserincidentsensordesignmethodarebroughtout,andtheF-Petalonwiththeinterferometricfiltercombinationisadopted.Fortheincidentlaserpulsewithacertainwavelength,thetransmittancedifferenceoftheinterferometricfiltersisindependentwithpolarizationofincidentlight,anddescendsalmostlinearlyastheincidentanglegetswider.Alaserincidentanglesensorexperimentalplatformisbuiltup,andtheexperimentiscarriedoutwithagivenlaserrangefinder.Astheresultsindicate,whentheincidentangleislessthan5o,thetransmittancedifferencemeasuredbythelaseranglesensorissignificantlylower,andthedeviationismorethan10%.Whiletheincidentangleisgreaterthan10o,thedeviationisreducedsignificantly.
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:AwedgeshapeSiLEDisdesignedandfabricatedwith0.35μmdouble-gratingstandardCMOStechnology.ThedevicestructureisbasedontheN-well-P+junction.TheP+hasawedgeshapeandissurroundedbytheN-well.ThemicrographsofSiLEDs'emittingandlayoutarecaptured.TheI-VcharacteristicandspectraoftheSiLEDaretested.Underroomtemperatureandbackwardbias,itsradiantluminosityis12nWat100mA,andthewavelengthoftheemittingpeakislocatedat764nm.
简介:Cupricoxide(CuO)isconsideredtobeapromisingmaterialforphotovoltaicapplications.Inthispaper,p-CuO/n-Sijunctionsolarcellswereobtainedbythermaloxidationofmetalliccopperfilmsdepositedonn-Sisubstratesat400℃for5h.X-raydiffractionpatternsshowthattheas-preparedfilmsareCuOwithmonocliniccrystallinestructure.HalleffectmeasurementresultsshowthatCuOfilmsarep-typeconduction.Adirectband-gapof~1.57eVfortheCuOfilmisdeducedfromUV-VisAbsorbancespectra.SolarcellsofCu/p-CuO/n-Si/AlstructureshowthatitsphotovoltaicbehaviorhasamuchwiderspectrumresponsewidthcomparedwiththatofSisolarcells.Inaddition,thephotocurrentofCuO/n-SijunctionisinvestigatedasafunctionofCuOfilmthickness,anditisfoundthatthecriticalthicknessforCuOonSiisabout250nm.