简介:Analgorithmofhighlymaneuveringtargettrackingisproposedtosolvetheproblemoflargetrackingerrorcausedbystrongmaneuver.Inthisalgorithm,anewestimator,namedasmulti-parameterfusionSinger(MF-Singer)modelisderivedbasedontheSingermodelandthefuzzyreasoningmethodbyusingradialaccelerationandvelocityofthetarget,andappliedtotheproblemofmaneuveringtargettrackinginstrongmaneuveringenvironmentandoperatingenvironment.ThetrackingperformanceoftheMF-Singermodelisevaluatedandcomparedwithothermanueveringtrackingmodels.ItisshownthattheMF-Singermodeloutperformsthesealgorithmsinseveralexamples.
简介:Thehighpowerholeyfiberisanefficientsupercontinuumlightsourcebyusingpicosecondpulse,whichisalessexpensivelasersourcecomparedwithlowpowerandexpensivefemtosecondlasersources.Inthispaper,ahighpowerhighlynonlinearholeyfiber(HN-HF)withalowconfinementlossisproposedforsupercontinuumlightsources.ThefinitedifferencemethodisusedtocalculatethedifferentpropertiesoftheproposedHN-HF.Highnonlinearcoefficientsareobtainedat1.06μm,1.31μm,and1.55μmwavelengthswithflattenedchromaticdispersionandlowconfinementlossessimultaneously.Moreover,numericalsimulationresultsshowthathighpowerbroadsupercontinuumspectrawithveryshortlengthoftheproposedphotoniccrystalfiberareachieved.
简介:Theultraviolet(UV)bandedgephotorefractivityofLiNbO_3:Zrat325nmhasbeeninvestigated.Theexperimentalresultsshowthattheresistanceagainstphotorefractionat325nmisquiteobviousbutnotasstrongasthatat351nm,whenthedopingconcentrationofZrreaches2.0mol%.ItisreportedthatthephotorefractivityinothertetravalentlydopedLiNbO_3crystals,suchasLiNbO_3:HfandLiNbO_3:Sn,isenhanceddramaticallywithdopingconcentrationoverthreshold.HerewegiveanexplicitexplanationonsuchseemlyconflictingbehaviorsoftetravalentlydopedLiNbO_3,whichisascribedtothecombinedeffectofincreasedphotoconductivityandtheabsorptionstrengthofthebandedgephotorefractivecenters.