简介:Inthispaper,onlynarrow-senseprimitiveBCHcodesoverGF(q)areconsidered.Aformula,thatcanbeusedinmanycases,isfirstpresentedforcomputingthedimensionofBCHcodes.ItimprovestheresultgivenbyMacWilliamsandSloanein1977.AnewmethodforfindingthedimensionofalltypesofBCHcodesisproposed.Insecondpart,itisprovedthattheBCHboundistheleaderofsomecyclotomiccoset,andweguessthattheminimumdistanceforanyBCHcodeisalsotheleaderofsomecyclotomiccoset.
简介:Thispaperpresentsthelowerboundsandupperboundsforthemeanvalueandvarianceofdistancedistributionofnon-linearcodesinGF(q).Bypresentingseveralexamples,itisshownthattheseboundscouldbeachieved.
简介:ThroughusingbothCr4+:YAGandGaAssaturableabsorbers,adiode-pumpeddoublepassivelyQ-switchedNd:GdVO4laserisrealizedandcomparedwithasinglepassivelyQ-switchedlaser.Thislasercangeneratesymmetricpulsetemporalprofilesandshorterpulses.Alaserpulsewidthof17nshasbeenachievedwiththeincidentpumppowerof8.5W.
简介:All-opticalregeneratorscanbeusedtosuppressamplifiedspontaneousemission(ASE)noiseintroducedbycascadederbiumdopedfiberamplifiers(EDFAs)inopticalfibercommunicationsystemsandleadtotheimprovementofopticalreceiversensitivity.ByintroducingtheQ-factortransferfunction(QTF),weevaluatetheQ-factorperformanceofdegeneratefour-wavemixing(DFWM)regeneratorswithclockpumpandrevealthedifferencesbetweentheoptimalinputpowersdeterminedfromthestaticanddynamicpowertranferfunction(PTF)andtheQTFcurves.Oursimulationshowsthattheclock-pumpregneratoriscapableofimprovingtheQ-facorandreceiversensitivityfor40Gbit/sASE-degradedreturn-to-zeroon-offkeying(RZ-OOK)signalby2.58dBand4.2dB,respectively.
简介:WeproposeanddemonstrateexperimentallyamultimodeoscillationQ-switchederbium-dopedfiberlaserwithafew-modefibercavity.ThedifferentcouplingprocessesofreflectionpeaksoffiberBragggratings(FBGs)whichactascavitymirrorsallowthedifferentoscillatingstates.Weobtainmicrosecondlightpulseoutputstateswhoseoscillationandoutputbeamshavedifferentmodecompositions,includinghighordermode.Suchastructureenablesthehighordermodeoscillationinthewholecavitywithanall-fiberstructure,whichhaspotentialapplicationsinmode-divisionmultiplexedsystemsandresearchofmultimodenonlineareffect.
简介:Ahigh-Qmicrowavephotonicfilterusingasemiconductoropticalamplifier(SOA)-basedmode-lockingfiberringlaserisproposed,analyzedandexperimentallydemonstrated.Theproposedmicrowavephotonicfiltercanrealizeahigh-Qfrequencyresponse,itiscompactwithoutanopticalsource,anditcanbeeasilytunedbyadjustinganopticalvariabledelaylineinaringcavity.AresultwithaQ-factorofabout236andarejectionratioofabout45dBisobtained.Themeasuredresultsandthetheoreticalestimationsagreeverywell.
简介:Adiode-pumpedacousto-optical(A-O)Q-switchedextra-cavityfrequency-doubledNd:YVO4/KTP(KTiOPO4)greenlaserformedwithasimpleplane-planecavityhasbeendemonstrated.Withtheincidentpumppowerof12.7W,A-OQ-switchedaverageoutputpowerat1064nmwas3.81Wwithadurationof25nsatarepetitionrateof20kHz,extra-cavityfrequencydoublingwithKTPasthenonlinearcrystalyieldedthemaximumoutputpowerof1.92Wat532nm,thecorrespondingopticalconversionefficiencyfrom1064nmto532nmlightis50.4%.Thecontinuous-wave(CW)laserpropertiesofdiodepumpedNd:YVO4crystaloperatingat1064nmhavebeenstudied.Withtheincidentpumppowerof25W,themaximumCWoutputpowerof13.81Wwasobtainedwiththecorrespondingopticalconversionefficiencyof55.24%.
简介:在这份报纸,消极地切换Q、锁模式的c切割在1.17m的做Nd的vanadate水晶self-Raman激光被使用Cr第一表明<啜class=“a-plus-plus”>4+:YAG。Nd的二晶体<啜class=“a-plus-plus”>3+:YVO4和Nd<啜class=“a-plus-plus”>3+:GdVO4被采用分别地产生激光。与13W的事件泵力量,在1.17m的678mW和852mW的平均产量力量分别地与1.8ns和2ns的切换Q的信封的持续时间被获得。锁模式的重复率分别地象2.3Hz和2.2GHz一样高。根据我们知道,切换Q的信封是最狭窄并且锁模式的重复率是最高目前在这块地里。另外,黄激光输出被使用解放也完成<潜水艇class=“a-plus-plus”>3O<潜水艇class=“a-plus-plus”>5频率加倍水晶。
简介:摘要近些年来,随着科技的快速发展,在日常生活中代替人们头脑计算的工具出现得越来越多,而随着这些工具的出现,人们的头脑计算能力明显地退化了很多.而且,这些工具逐渐出现在小学生的视野中,一些学生为了方便,在学习数学知识的过程中,进行计算的过程中往往都是借助计算器.计算器的使用严重阻碍了小学生的头脑思考,严重抑制了学生的计算思维.此外,在小学数学教学的过程中,一些教师没有对培养学生的计算能力做出相应的关注,教师的教学侧重点只是偏重于教学知识的传授.为此,如何在小学数学教学中合理锻炼学生的计算思维,培养学生的计算能力是值得教师探究的.本文结合笔者多年的小学数学教学经验,对小学数学培养学生计算能力的教学策略进行探究。