简介::Twonovelpoly[(3-alkyhhiophene-2,5-diyl)-(benzylidenequinomethane-2,5-diyl)s]derivatives,poly[(3-butylthiophene-2,5-diyl)-(p-N,N-dimethylamino)benzylidenequinomethane-2,5-diyl)](PBTDMABQ)andpoly[-(3-octylthiophene2,5-diyl)-(p-N,N-dimethylamino)benzylidenequinomethane-2,5-diyl)](POTDMABQ),weresynthesized.Thebandgapsofthetwopolymersarecalculatedas1.75eVforPBTDMABQand1.69eVforPOTDMABQ,respectively.Thehomogenousfilmsofthetwopolymerswerepreparedandtheirthird-ordernonlinearopticalpropertieswerestudiedbythebackwarddegeneratefour-wavemixingat532nm.Byusingtherelativemeasurementtechnique,thethird-ordernonlinearopticalsusceptibilitiesofPBTDMABQandPOTDMABQarecalculatedas5.62×10^-9and1.22×10^-8ESU,respectively.Itisfoundthatsubstitutedalkygroupshavestrongeffectsonthebandgapandnonlinearopticalpropertiesofthetwopolymers.Therelativelybigthird-ordernonlinearopticalsusceptibilitiesandsmallbandgapofPOTDMABQresultedmainlyfromthelongeralkylwithstrongelectron-donatingabilitycanenhancethedelocationdegreeofconjugatedπelectronics.
简介:正如手机、MP3等数码产品一样,目前笔记本电脑与商务人士的生活联系得越来越紧密,笔记本电脑的便携性与移动性使之成为商务人士工作的一部分。笔记本电脑除了要具有良好的性能和丰富的功能之外,还需要优雅的外观来显示商务人士的身份、地位、品位、实力等象征,富士通正是瞄准了这一市场,推出了新款S系列专门针对商务人士的笔记本电脑。与之前推出的LifeBookS系列产品一样,这款6月21日才在全国正式推出的富士通新产品LifeBookS7021也具有纤薄、时尚的外观,并以“蝴蝶的轻盈飞舞”将富士通经典S系列的深邃内涵做出了更新的诠释。S7021继承了上一代S系列经典产品S7011的所有功能与特色,并且是富士通推出的第一款采用Sonoma迅驰平台的笔记本电脑产品。
简介:A10Gbit/srecirculatingsystemisconfiguredwithChirpedFiberBraggGrating(CFBG)forthedispersioncompensation.Forthefirsttime,thetransmissiondistanceintheloopreaches1000kmwithbiterrorrateof10-9.Theeffectofthegroupdelayrippleofthefibergratingisalsoinvestigatedintherecirculatingsystems,anditisshownthatthetransmissiondistanceislimitedto4cycles(4×167.1km)intheloopwiththepowerpenaltyfluctuationbelow1.0dB.Thusthegroupdelayrippleshouldbereducedtoallowforthewavelengthdriftof±5GHz.Attheendofthisletter,theprinciplesaregivenfordesigninglonghaulrecirculatingsystemswithdispersioncompensationCFBG.
简介:Atheoreticalmodelinthe1900nmwavebandforamplifiedspontaneousemission(ASE)ofthulium-dopedsilicafiberispresented.TheASEspectralpowerasfunctionsofthefiberlengthandthepumppowerisinvestigatedbysolvingtherateandpropagationequations.Bycalculation,whentheconcentrationofthuliuminfiberis2.25×1025m-3,thefibercorediameteris2.6μm,andthepumppoweris200mWat808nm,theoptimalfiberlengthis8.1m,andtheoutputpowerofASEcanreach60mWintherangeof1800-1950nmwiththisfiberlength.Theoptical-to-opticalconversionis30.3%.Theoptimalpumppoweralsocanbeobtainedbythismodel.
简介:AnewmethodisproposedtoimplementanopticalS-Rflip-flopbypolarizationencodedlightsignal,necessaryopticalnonlinearmaterialandhalf-waveplate.Inthissystemtherealtimespeedofoperationcanbeachieved,andatthetimeoftransmissiontheaveragepowerofabyteremainsconstant.Thispolarizationencodedflip-flopcanactasamemorycell.
简介:Soft-switchingtechniquesareattractivetounity-power-factorAC/DCconverterintheviewofthesizereductionandEMIsuppression.Asoft-switchedboostPFCconverterhasbeenstudiedbasedonitstopologyanalysis,PSIMsimulationandcircuitexperiment.Aspeciallimitationofsoft-switchingtechniqueshasbeenfoundintheirAC/DCapplications.
简介:本文介绍了上海移动新卢湾15环6个汇聚点10Gbit/s设备改造安装工程,并对工程中施工难点和问题做了阐述。