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25 个结果
  • 简介:Weexperimentallyinvestigatedthenonlinearopticalresponseinfew-layeroxidizedblackphosphorus(OBP)bythefemtosecondZ-scanmeasurementtechnique,andfoundthatOBPnotonlypossessesstrongultrafastsaturableabsorptionbutalsoanonlinearself-defocusingeffectthatisabsentinblackphosphorus(BP).Thesaturableabsorptionpropertyoriginatesmainlyfromthedirectbandstructure,whichisstillmaintainedinOBP.Theemergenceofself-defocusingmightoriginatefromthecombinedconsequencesoftheoxygen-induceddefectsinBP.Ourexperimentalfindingsmightconstitutethefirstexperimentalevidenceonhowtodynamicallytuneitsnonlinearproperty,offeringaninroadintailoringitsopticalpropertiesthroughchemicalmodification(oxidation,introducingdefects,etc.).Theversatileultrafastnonlinearopticalproperties(saturableabsorptionandself-defocusing)implyasignificantpotentialofthelayeredOBPinthedevelopmentofunprecedentedoptoelectronicdevices,suchasmodelockers,opticalswitches,laserbeamshapers,andwavelengthconverters.

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  • 简介:Inordertoprovidethebasisforparameterselectionofvocaldiseasesclassification,anonlineardynamicmodelingmethodisproposed.Abiomechanicalmodelofvocalcordswithpolyporparalysis,whichcouplestoglottalairflowtoproducelaryngealsoundsource,isintroduced.Andthenthefundamentalfrequencyanditsperturbationparametersaresolved.Poincaresectionandbifurcationdiagramareappliedtononlinearanalysisofmodelvibration.Bychangingthepathologicalparametersorsubglottalpressure,thechangesoffundamentalfrequencyandLyapunovexponentsareanalyzed.Thesimulationresultsshowthat,vocalcordparalysisreducesthefundamentalfrequency,andthechaosoccursonlywithinacertainpressurerange;whilevocalcordwithapolypdon’treducethefundamentalfrequency,chaosdistributesthroughouttheentirerangeofpressure.Thereforethisstudyishelpfulforclassificationofpolypandparalysisbytheacousticdiagnoses.

  • 标签: 非线性动力学模型 分类 麻痹 LYAPUNOV指数 发声
  • 简介:Oneofthemostinterestingproblemsofnonlineardifferentialequationsistheconstructionofpartialsolutions.Anewmethodispresentedinthispapertoseekspecialsolutionsofnonlineardiffusionequations.ThismethodisbasedonseekingsuitablefunctiontosatisfyBernolliequation.Manynewspecialsolutionsareobtained.

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  • 简介:Weinvestigatethenonlinearresponseofterahertz(THz)metamaterialperfectabsorbersconsistingofelectricsplitringresonatorsonGaAsintegratedwithapolyimidespacerandgoldgroundplane.Theseperfectabsorbersonbulksemi-insulatingGaAsarecharacterizedusinghigh-fieldTHztime-domainspectroscopy.Theresonancefrequencyredshifts20GHzandtheabsorbanceisreducedby30%astheincidentpeakfieldisincreasedfrom30to300kV/cm.ThenonlinearresponsearisesfromTHzfielddriveninterbandtransitionsandintervalleyscatteringintheGaAs.ToeliminatetheFresnellossesfromtheGaAssubstrate,wedesignandfabricateaflexiblemetamaterialsaturableperfectabsorber.Theabilitytocreatenonlinearabsorbersenablesappealingapplicationssuchasopticallimitingandself-focusing.

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  • 简介:WestudytheDirichletproblemassociatedtostronglynonlinearparabolicequationsinvolvingp(x)structureinW_0~(1,x)L~(p(x))(Q).WeprovetheexistenceofweaksolutionsbyapplyingGalerkin'sapproximationmethod.

  • 标签: 非线性的寓言的方程 存在 可变代表 弱答案
  • 简介:ThisstudyconcernscalculationofphasedarraybeamfieldsofthenonlinearRayleighsurfacewavesbasedontheintegralsolutionsforanonparaxialwaveequation.SincetheparabolicapproximationmodelfordescribingthenonlinearRayleighwaveshascertainlimitationsinmodelingthesoundbeamfieldsofphasedarrays,amoregeneralmodelequationandintegralformsofquasilinearsolutionsareintroduced.SomefeaturesofsteeredandfocusedbeamGeldsradiatedfromalinearphasedarrayofthesecondharmonicRayleighwavearepresented.

  • 标签: 相控阵列 瑞利面波 非线性 波束 傍轴波动方程 模型模拟
  • 简介:Inthispaper,byusingtheGuo-Krasnoselskii'sfixed-pointtheorem,weestablishtheexistenceandmultiplicityofpositivesolutionsforafourth-ordernonlineareigenvalueproblem.Thecorrespondingexamplesarealsoincludedtodemonstratetheresultsweobtained.

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  • 简介:Westudythedynamicsofthecubic–quinticnonlinearSchr?dingerequationbythesymplecticmethod.Thebehaviorsoftheequationarediscussedwithharmonicallymodulatedinitialconditions,andthecontributionsfromthequintictermarediscussed.Weobservetheellipticorbit,homoclinicorbitcrossing,quasirecurrence,andstochasticmotionwithdifferentnonlinearparametersinthissystem.Numericalsimulationsshowthatthechangingprocessesofthemotionofthesystemandthetrajectoriesinthephasespacearevariousfordifferentcubicnonlinearparameterswiththeincreaseofthequinticnonlinearparameter.

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  • 简介:BasedonthecontinuityofthederivativesoftheNon-UniformRationalB-Splines(NURBS)curveandtheJaumannstrainmeasure,thepresentpaperadoptedthepositioncoordinatesofthecontrolpointsasthedegreesoffreedomanddevelopedaplanarrotation-freeEuler-Bernoullibeamelementforisogeometricanalysis,wherethederivativesofthefieldvariableswithrespecttothearc-lengthwereexpressedasthesumoftheweightedsumofthepositioncoordinatesofthecontrolpoints,andtheNURBSbasisfunctionswereusedastheweightfunctions.Furthermore,theconceptofbendingstripwasusedtoinvolvetherigidconnectionbetweenmultiplepatches.Severaltypicalexampleswithgeometricnonlinearitieswereusedtodemonstratetheaccuracyandeffectivenessoftheproposedalgorithm.Thepresentedformulationfullyaccountsforthegeometricnonlinearitiesandcanbeusedtostudythesnap-throughandsnap-backphenomenaofflexiblebeams.

  • 标签: isogeometric 分析 NURBS 没有旋转的横梁 弯曲长带方法 突然将球踢回
  • 简介:Inthispaper,severalnewconstant-amplitudeandvariable-amplitudewavesolutions(namely,travelingwavesolutions)ofageneralizednonlinearSchrdingerequationareinvestigatedbyusingtheextendedhomogeneousbalancemethod,wherethebalancemethodisappliedtosolvetheRiccatiequationandthereducednonlinearordinarydifferentialequation,respectively.Inaddition,stabilityanalysisofthosesolutionsarealsoconductedbyregularphaseplanetechnique.

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  • 简介:Thequasilinearhyperbolicequationwithnonlineardampingisconsideredinthispaper,anewasymptoticprofileforthesolutiontotheequationisobtainedbysuitablychoosingtheinitialdataofthecorrespondingparabolicequation,theconvergenceratesofthenewprofilearebetterthanthatobtainedbyNishihara(1997,J.DifferentialEquations137,384-395)andH.-J.Zhao(2000,J.DifferentialEquations167,467-494).

  • 标签: 拟线性双曲型方程组 非线性阻尼 渐近分布 收敛速度 抛物型方程 渐近曲线
  • 简介:WestudythegeneralizedDarbouxtransformationtothethree-componentcouplednonlinearSchr¨odingerequation.First-andsecond-orderlocalizedwavesareobtainedbythistechnique.Infirst-orderlocalizedwave,wegettheinteractionalsolutionsbetweenfirst-orderroguewaveandone-dark,one-brightsolitonrespectively.Meanwhile,theinteractionalsolutionsbetweenone-breatherandfirst-orderroguewavearealsogiven.Insecond-orderlocalizedwave,one-dark-one-brightsolitontogetherwithsecond-orderroguewaveispresentedinthefirstcomponent,andtwo-brightsolitontogetherwithsecond-orderroguewavearegainedrespectivelyintheothertwocomponents.Besides,weobservesecond-orderroguewavetogetherwithone-breatherinthreecomponents.Moreover,byincreasingtheabsolutevaluesoftwofreeparameters,thenonlinearwavesmergewitheachotherdistinctly.Theseresultsfurtherrevealtheinterestingdynamicstructuresoflocalizedwavesinthethree-componentcoupledsystem.

  • 标签: 非线性波 耦合系统 三分量 局域波 DARBOUX变换 方程
  • 简介:Inthispaper,weconsideranonlinearsystemofreactiondiffusionequationsarisingfrommathematicalneuroscienceandtwononlinearscalarreactiondiffusionequationsundersomeassumptionsontheircoefficients.Themainpurposeistocoupletogetherlinearizedstabilitycriterion(theequivalenceofthenonlinearstability,thelinearstabilityandthespectralstabilityofthestandingpulsesolutions)andEvansfunctionstoaccomplishtheexistenceandinstabilityofstandingpulsesolutionsofthenonlinearsystemofreactiondiffusionequationsandthenonlinearscalarreactiondiffusionequations.TheEvansfunctionsforthestandingpulsesolutionsareconstructedexplicitly.

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  • 简介:在这份报纸,一条直接概率的途径(DPA)被介绍为能是任何一个的环境负担激动的非线性的系统提出并且解决时刻方程一静止或nonstationary随机过程。建议方法有的优点从起始的条件和相应外部刺激的统计特征直接获得回答时刻。首先,回答时刻方程直接基于DPA被导出,它完全独立于它?后来,关于关联的特定的假设都不刺激组织的/filtering途径被做。由在Gaussian闭合下面解决他们,回答时刻能被获得。随后,为时刻方程的数字答案的一个多尺度的算法被利用改进计算效率并且避免许多墙钟时间。最后,有蒙特卡罗(MC)模拟的结果的比较给好同意。而且,多尺度的算法的优点被一个设计例子也以效率表明。

  • 标签: 指导概率的途径 非线性的动态系统 Nonstationary 随机的过程 回答时刻 多尺度的算法
  • 简介:Inthispaper,westudythenonexistenceandlongtimebehaviorofweaksolutionforthedegenerateparabolicequation?_tu~n=u~mdiv(|▽_u~m|~(p-2)▽u~m)+γ|▽u~m|~p+βu~nwithzeroboundarycondition.Blow-uptimeisderivedwhentheblow-updoesoccur.

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  • 简介:这份报纸与uncertain-but-bounded参数或起始的条件为非线性的系统的动态反应分析用衍生物信息建议一个新非恼人的混合间隔方法。这个方法与存在多项式近似间隔方法相比提供更紧密的答案范围。用Chebyshev基础的间隔算术和用一般形式的间隔算术修改了仿射的基础因为多项式被开发为间隔计算获得更紧密的界限。为了进一步减少overestimation,由间隔算术的包的效果引起了,当动态回答是关于所有不明确的变量的monotonic时,动态回答的衍生物信息被用来完成准确溶液。最后,有非线性的二个典型数字例子被使用特别地,表明建议混合间隔方法的有效性它有效地为特定的timepoints控制overestimation的能力。

  • 标签: 非恼人的混合间隔方法 动态反应分析 不明确的非线性的系统 多项式近似 间隔算术 衍生物信息
  • 简介:Inthispaper,aclassofparameter-freefilledfunctionsisproposedforsolvingbox-constrainedsystemofnonlinearequations.Firstly,theoriginalproblemisconvertedintoanequivalentglobaloptimizationproblem.Subsequently,aclassofparameter-freefilledfunctionsisproposedforsolvingtheproblem.Somepropertiesofthenewclassoffilledfunctionsarestudiedanddiscussed.Finally,analgorithmwhichneithercomputesnorexplicitlyapproximatesgradientsduringminimizingthefilledfunctionsispresented.Theglobalconvergenceofthealgorithmisalsoestablished.Theimplementationofthealgorithmonseveraltestproblemsisreportedwithsatisfactorynumericalresults.

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  • 简介:Byusingthemethodofdynamicalsystem,theexacttravellingwavesolutionsofthecouplednonlinearSchrdinger-KdVequationsarestudied.Basedonthismethod,allphaseportraitsofthesystemintheparametricspacearegiven.Allpossibleboundedtravellingwavesolutionssuchassolitarywavesolutionsandperiodictravellingwavesolutionsareobtained.WiththeaidofMaplesoftware,thenumericalsimulationsareconductedforsolitarywavesolutionsandperiodictravellingwavesolutionstothecouplednonlinearSchrdinger-KdVequations.Theresultsshowthatthepresentedfindingsimprovetherelatedpreviousconclusions.

  • 标签: dynamical system method COUPLED NONLINEAR SchrdingerKd
  • 简介:Inthispaper,themodifiedextendedtanhmethodisusedtoconstructmoregeneralexactsolutionsofa(2+1)-dimensionalnonlinearSchr¨odingerequation.WiththeaidofMapleandMatlabsoftware,weobtainexactexplicitkinkwavesolutions,peakonwavesolutions,periodicwavesolutionsandtheir3Dimages.

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