Math model of metal heating under action by laser beam智慧树知到答案2024年1

Mathmodelofmetalheatingunderactionbylaserbeam1智慧树知到答案2024年第一章测试

Stepsatthemathmodelingare（）。

A:Quality’sanalysisofuniquenesssolutionormultiplicityoftheproblemsolution.Forthisaim,asarule,thepointwisemodelisderivedfromPDEs.B:Derivationoftheconservationlaws(integralsofmotions)fortheproblemunderconsideration.C:Introducingdimensionlessvariablesandwritingsimilarityparameters(π-parameters).D:Developingfinite-differenceschemes(finite-elementsscheme)fornumericalsolutionoftheproblemunderconsideration.E:Analysisofthephysicalandchemicalprocessesoccurringinprocessunderconsideration.F:Writingofthedifferential(andother)equationsdescribingtheprocessunderconsideration.G:Analysisofphysicalunitsofeachtermsinvolvingintheequations.

答案:FWhichofthefollowingoptionsistherequirementforthenumericalmethod?（）。

A:AlloftheaboveB:Thenumericalmethodmustbetestedbyusingthewell-knownsolutionsoftheproblemunderconsideration.C:FDSmustbeeconomicalone.Itmeansthat3Dor2Ddifferenceequationsmustbesolvedassequenceof1Ddifferenceequations.D:Highorderofapproximationofthedifferentialequationsbynumericalsolution.

答案:AThefollowingareapplicationsoflaserradiationinthefieldofphysics?（）。

A:Opticaldatastorage(CD,SVD,5Dopticalmemory)B:AstrophysicsC:NanophotonicsD:Photochemistry

答案:ABCWhatfieldscanlaserradiationbeusedin?（）。

A:LaserMedicineB:LaserChemistryC:PhysicsD:LaserBiology

答案:ABCDWhatarethepropertiesoflaserradiation?（）。

A:Laseremitsmonochromaticwave.Usuallylaseremitssinglewavelength.B:Stimulatedemission.C:Divergenceoflaserbeamissmall.D:Coherence(spatial,temporal).E:Polarization.

答案:ABCDETheonethatcanexplaintheexperimentalcurveofblackbodyradiationperfectlyis（）

A:Planck'sformulaB:Einstein'sformulaC:theRiley-PierceequationD:Wien'sformula

答案:AAconcavecavitywithaconcavemirrorofradiusRequaltothecavitylengthLisa（）.

A:unsteadycavityB:CriticalcavityC:UncertainD:Stabilizingcavity

答案:BThewavelengthoftheCO2laseris（）

A:810nmB:1064nmC:335nmD:10.6μm

答案:DThebasicstructureofthelaserconsistsofelectricalworkingmatter,pumpsourceand（）threeparts.

A:ReflectorB:OpticalresonantcavityC:WindowmirrorD:Affectedpole

答案:BCarbondioxidelaserscommonlyusedgasmixturecompositioniscomposedof（）,helium,argon,nitrogen.

A:CarbondioxideB:NeongasC:CarbonmonoxideD:Oxygen

答案:A

第二章测试

Whattypeoflaserdoesthecarbondioxidelaserbelongto?（）

A:Solid-statelaserB:SemiconductorlaserC:GaslaserD:Fiberlaser

答案:CWhenthepulseenergyiscertain,thenarrowerthepulsewidth,itmeansthetimeenergydensitywithtimeasthedenominator（）.

A:thesmallerB:ThegreaterC:ConstantD:Uncertain

答案:BForauniformlybroadenedmedium,thesmall-signalgaincoefficientatthecentercenterfrequencyisG0(v0),andwhenI=Is,saturationissignificant,andthenon-small-signalcenter-frequencygaincoefficientis:（）.

A:B:C:D:

答案:BThefollowingstatementabouttheelectricfieldinductionformulaiscorrect（）。

A:ε(z,x,y,t)isdielectricpermittivityB:P(z,x,y,t)ispolarizationofamediumC:allD:E(z,x,y,t)iselectricfieldstrength

答案:CWhatistheDuffing’sequationusedtocalculateelectrondisplacement?（）

A:B:C:D:

答案:DThethresholdconditionistheformationoflaser（）。

A:necessarycondition.B:sufficientnecessarycondition.C:Indeterminate.D:sufficientcondition.

答案:BWhenalaserpropagatesfromonemediumtoanotherwithadifferentrefractiveindex,a(C)willappearattheinterfacebetweenthemedia（）。

A:RefractionB:NeitherC:ReflectionsD:Reflectionandrefraction

答案:DThecollisionalbroadeningspectrallineis（）。

A:GaussianlinetypeB:ParabolictypeC:HyperbolictypeD:Lorentzianlinear

答案:DParticlenumberreversaldistributionstatemicroscopicparticlessatisfy（）

A:BormanzdistributionB:GaussiandistributionC:NegativetemperaturedistributionD:Fermidistribution

答案:CAtacertaintemperature,theoddsofspontaneousradiationare（）timesgreaterthantheoddsofexcitedradiation

A:B:C:D:

答案:B

第三章测试

TheDopplerbroadeningoftheCO2spectrallineis53MHz,andtheextremevalueofthespectrallinefunctioncorrespondingtothecentralfrequencyis（）。

A:1.7×10-9sB:1.7×109HzC:1.7×10HzD:1.7×10-9Hz

答案:AQ-modulatedlaserscanusuallyobtain（）magnitudeshortpulses.

A:fsB:μsC:msD:ns

答案:DRubylaserisatypical（）system。

A:Four-energylevelB:Multi-energylevelC:ThreeenergylevelD:Dienergylevel

答案:CDopplerbroadeninghasoccurredin（）media.

A:SolidsB:liquidsC:liquidsD:Isolates

答案:BHe-Nelasersbelongtothetypical（）system.

A:fourenergylevels,B:multi-energylevelC:twoenergylevelsD:threeenergylevels

答案:AThecharacteristicsoflasercavityoscillationmodeare（）。

A:Thedivergenceangleofthelaserbeamforeachmode.B:Theelectromagneticfieldtheoryofthemode.C:Thesimpleharmonicfrequencyofthemode.D:Therelativepowerlossexperiencedbythemodeduringoneroundtripinthecavity.

答案:ABCDForthesamemedium,thesmallsignalgaincoefficientvarieswith（）。

A:particlenumberdensityB:SpectrallinewidthC:ExcitationpowerD:Spontaneousradiationchance

答案:CNaturalbroadeningiscausedby（）.

A:collisionsofparticlesB:theDopplereffectC:excitedstateshaveacertainlifetimeD:vibrationofparticles

答案:CTheresonantfrequencyofthelongitudinalmodeoftheresonantcavityis（）。

A:B:C:D:

答案:BSymmetricconfocalcavitybasemodelightwaistfor（）。

A:B:C:D:

答案:C

第四章测试

TherelationshipbetweentheEinsteincoefficientofspontaneousradiationandtheaveragelifetimeτoftheexcitedstateE2is（）。

A:B:C:D:

答案:BTherelationshipbetweenEinsteincoefficientsA21andB21is（）

A:B:C:D: