简介:BasedontheEigenandCrow-Kimuramodelswithasingle-peakfitnesslandscape,weproposethefitnessvaluesofallsequencetypestobeGaussiandistributedrandomvariablestoincorporatetheeffectsofthefluctuationsofthefitnesslandscapes(noiseofenvironments)andinvestigatetheconcentrationdistributionanderrorthresholdofquasispeciesbyperforminganensembleaveragewithinthistheoreticalframework.Wefindthatasmallfluctuationofthefitnesslandscapecausesonlyaslightchangeintheconcentrationdistributionanderrorthreshold,whichimpliesthattheerrorthresholdisstableagainstsmallperturbations.However,forasizablefluctuation,quitedifferentfromthepreviousdeterministicmodels,ourstatisticalresultsshowthatthetransitionfromquasi-speciestoerrorcatastropheisnotsosharp,indicatingthattheerrorthresholdislocatedwithinacertainrangeandhasashifttowardalargervalue.Ourresultsarequalitativelyinagreementwiththeexperimentaldataandprovideanewimplicationforantiviralstrategies.
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简介:我们采用nonequilibrium格林的函数方法理论上在一个使变形的分子学习Kondo效果,它被当作一个电子声子相互作用(EPI)系统。为声子部分的自我精力在标准许多身体被计算图解的扩大直到在EPI力量的第二份订单。我们发现多重帮助声子的Kondo卫星除平常的Kondo回声以外产生。在反平行的磁性的配置切开主要Kondo山峰和帮助声子的卫星仅仅发生因为不均匀的点铅couplings,而是它从为平行磁性的配置的对称是免费的。EPI力量和震动的频率能提高主要Kondo和卫星切开的旋转。压制的零偏爱的Kondo回声能被使用一个外部磁场恢复,这被显示出,其大小显著地依赖于phononic效果。尽管在隧道联合的不对称现象没有贡献到Kondo山峰切开的纺纱的恢复,它能缩小需要交换在大否定剧降和大积极山峰之间的通道磁致电阻比率的外部地。
简介:Thediscreteiterativemapmodelofpeakcurrent-modecontrolledbuckconverterwithconstantcurrentload(CCL),containingtheoutputvoltagefeedbackandrampcompensation,isestablishedinthispaper.BasedonthismodelthecomplexdynamicsofthisconverterisinvestigatedbyanalyzingbifurcationdiagramsandtheLyapunovexponentspectrum.Theeffectsoframpcompensationandoutputvoltagefeedbackonthestabilityoftheconverterareinvestigated.Experimentalresultsverifythesimulationandtheoreticalanalysis.Thestabilityboundaryandchaosboundaryareobtainedunderthetheoreticalconditionsofperiod-doublingbifurcationandbordercollision.Itisfoundthattherearefouroperationregionsinthepeakcurrent-modecontrolledbuckconverterwithCCLduetoperiod-doublingbifurcationandborder-collisionbifurcation.Researchresultsindicatethatrampcompensationcanextendthestableoperationrangeandtransfertheoperatingmode,andoutputvoltagefeedbackcaneventuallyeliminatethecoexistingfast-slowscaleinstability.
简介:Usingcryogeniclasertechnology,itisnowpossibletodesignanddemonstratelasersthathaveconcomitanthighaverageandpeakpowers,withnear-diffraction-limitedbeamquality.WerefertothesenewlasersystemsasHAPPlasers.Inthispaper,wereviewimportantlasercrystalmaterialspropertiesatcryogenictemperature,withanemphasisonYblasers,anddiscusstheimportantdesignconsiderations,includingthelaser-induceddamagethreshold,nonlineareffectsandthermaleffects.Acomprehensivemodelispresentedtodescribediodepulsedpumpingwitharbitrarydurationandrepetitionrate,andisusedwiththeFrantz–Nodvikequationtodescribe,tofirstorder,theperformanceofHAPPlasersystems.Acomputercodewithrepresentativeresultsisalsodescribed.
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简介:Pulsecontrastisacrucialparameterofhighpeak-powerlaserssincetheprepulsenoisemaydisturblaser–plasmainteractions.Contrastmeasurementisthusaprerequisitetotacklethecontrastchallengeinhighpeak-powerlasers.Thispaperpresentstheprogressreviewofsingle-shotcross-correlator(SSCC)forreal-timecontrastcharacterization.WebeginwiththekeytechnologiesthatenableanSSCCtosimultaneouslypossesshighdynamicrange(1010),largetemporalwindow(50–70ps)andhighfidelity.WealsosummarizetheinstrumentationofSSCCprototypesandtheirapplicationsonfivesetsofpetawattlaserfacilitiesinChina.Finally,wediscusshowtoextendcontrastmeasurementsfromtimedomaintospatiotemporaldomain.Real-timeandhigh-dynamic-rangecontrastmeasurements,providedbySSCC,cannotonlycharacterizevariouscomplexnoisesinhighpeak-powerlasersbutalsoguidethesystemoptimization.
简介:Wereportonthedesign,realization,andoutputperformanceofadiode-pumpedhigh-peak-powerpassivelyQ-switchedNd:YAG∕Cr4+:YAGcompositemediummonolithiclaserwithfour-beamoutput.Theenergyofalaserpulsewashigherthan3mJwithdurationof0.9ns.Theproposedsystemhastheabilitytochooseindependentlythefocusofeachbeam.Suchalaserdevicecanbeusedformultipointignitionofanautomobilegasolineengine,butcouldalsobeofinterestforignitioninspacepropulsionorinturbulentconditionsspecifictoaeronautics.
简介:Bysimultaneouslyemployingbothanelectro-opticmodulatorandcarbonnanotubesaturableabsorber(CNT-SA)inadual-lossmodulator,asubnanosecondsinglemode-lockingpulseunderneathaQ-switchedenvelopewithhighpeakpowerwasgeneratedfromadoublyQ-switchedandmode-locked(QML)Nd:Lu0.15Y0.85VO4laserat1.06μmforthefirsttime,toourknowledge.CNTswithdifferentwallstructures—single-walledCNTs(SWCNTs),double-walledCNTs(DWCNTs),andmulti-walledCNTs(MWCNTs)—wereusedasSAsintheexperimenttoinvestigatethesinglemode-lockingpulsecharacteristics.Atpumppowerof10.72W,themaximumpeakpowerof1.312MWwasobtainedwiththeDWCNT.