简介:Areviewontheprogressofpowerful2μmsilicafibersourcesinpastdecadesispresented.Wereviewthestate-of-the-artrecordsandrepresentativeachievementsof2μmhigh-average-powercontinuouswave,pulsedfiberlasersandamplifiers,andpowerfulsuperfluorescentsources.Challengeswhichlimitthefurtherpowerscalingof2μmsilicafibersourcesarediscussed,includingpumpingbrightnesslimitation,thermalproblem,andnonlineareffects.Potentialandpromisingroadmapstogobeyondtheselimitations,liketandempumpingandbeamcombining,arediscussed.Prospectsofpowerful2μmsilicafibersourcesarealsopresentedintheendofpaper.
简介:TheproblemsofcharacteristicpolynomialassignmentinFomasini-Marchesini(F-M)modelⅡof2-Dsystemsareinvestigated.Thecorrespondingclosed-loopsystemsdescribedbyF-MmodelIIareobtainedviathestatefeedback.Usingthealgebraicgeometrymethod,thecharacteristicpolynomialassignmentinthedosed-loopsystemsisdiscussed.Intermsofthetheoryofalgebraicgeometry,theproblemofcharacteristicpolynomialassignmentistransferredtotheonewhetherarationalmappingisonto.SufficientconditionsforalmostarbitraryassignmentcoefficientsofcharacteristicpolynomialinF-MmodelⅡof2-Dsystemsviastatefeedbackarederived,andtheyareavailableformulti-inputcases.Italsohasbeenshownthatthismethodcanbeappliedtoassignthecharacteristicpolynomialwithoutputfeedback.Thesufficientconditionsforalmostarbitraryassignmentcoefficientsofcharacteristicpolynomialofmulti-input2-DsystemsdescribedbyF-MmodelⅡwithoutputfeedbackareestablished.
简介:研究表明含氟气体的性质决定了原子氟(F)的转化效率,通常在CxFy气体中x的值越大,氟(F)的转化效率也就会越高。所以C3F8(八氟丙烷)比C2F6(乙氟烷)具有更高的利用效率,更少的PFC(全氟化物)的排放。文章主要研究在以四乙氧基硅烷(TOES)为基础的离子增强化学气相沉积(PlasmaEnhancedChemicalVaporDeposition,PECVD)的清洗制程中,利用分解效率高的C3F8气体取代C2F6气体。通过实验设计(DesignOfExperiment,DOE),调整腔体压力、射频(RF)功率、气体流量等参数,最终得到最优化的新清洗配方。应用到实际的量产中,有效地降低了成本,减少了PFC的排放。
简介:Inthispaper,wedemonstratetheacetylehe(C2H2)sensorwithhighsensitivityusingahollow-corephotonicbandgapfiber(HC-PCF).ExperimentsformeasuringC2H2concentrationsingasmixtureareperformed.Usinga2m-longHC-PCFasgascell,thespectrumofacetyleneatn1+n3bandhasbeenmeasured,andtheP11-branchhasbeenselectedforthepurposeofsensing.Aminimumdetectivityof143partspermillionbyvolume(ppmv)forthesystemconfigurationisestimated.
简介:ThepreparationofPT/PEK-cfilmsisreportedaswellastheirdielectricandopticalproperties.Thec-axisorientationratioofthefilmsis68%.Dielectricconstantandlossfactorat10kHzisabout4.023F/mand0.003,respectively.Therefractiveindicesofthefilms,neandno,are1.6573and1.6278at0.63μmwavelength,respectively.Theopticalband-gapofthefilmwithathicknessof2.33μmisfoundtobe3.06eV
简介:Superluminescencediode(SLD)moduleswithwidespectrumcharacteristicsarerequiredinfibergyroscopes.A1.3μmbutterflypackagedsuperluminescencediodewiththespectrumwidthover30nmisreportedandrecentadvancesinprocessofSLDisdescribedinthepaper.TheSLDmoduleshavebeenappliedtofibergyroscopes.
简介:Asimpleandeffectivegreedyalgorithmforimageapproximationisproposed.Basedonthematchingpursuitapproach,itischaracterizedbyareducedcomputationalcomplexitybenefitingfromtwomajormodifications.First,ititerativelyfindsanapproximationbyselectingMatomsinsteadofoneatatime.Second,theinnerproductcomputationsareconfinedwithinonlyafractionofdictionaryatomsateachiteration.Themodificationsareimplementedveryefficientlyduetothespatialincoherenceofthedictionary.Experimentalresultsshowthatcomparedwithfullsearchmatchingpursuit,theproposedalgorithmachievesaspeed-upgainof14.4~36.7timeswhilemaintainingtheapproximationquality.