Math model of metal heating under action by laser beam知到智慧树章节测试课后答案2024年秋华南理工大学

Mathmodelofmetalheatingunderactionbylaserbeam知到智慧树章节测试课后答案2024年秋华南理工大学第一章单元测试

Stepsatthemathmodelingare（）。

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

答案:Writingofthedifferential(andother)equationsdescribingtheprocessunderconsideration.Whichofthefollowingoptionsistherequirementforthenumericalmethod?（）。

A:Highorderofapproximationofthedifferentialequationsbynumericalsolution.B:FDSmustbeeconomicalone.Itmeansthat3Dor2Ddifferenceequationsmustbesolvedassequenceof1Ddifferenceequations.C:AlloftheaboveD:Thenumericalmethodmustbetestedbyusingthewell-knownsolutionsoftheproblemunderconsideration.

答案:AlloftheaboveThefollowingareapplicationsoflaserradiationinthefieldofphysics?（）。

A:Opticaldatastorage(CD,SVD,5Dopticalmemory)B:NanophotonicsC:AstrophysicsD:Photochemistry

答案:Opticaldatastorage(CD,SVD,5Dopticalmemory)；Nanophotonics；AstrophysicsWhatfieldscanlaserradiationbeusedin?（）。

A:LaserMedicineB:PhysicsC:LaserBiologyD:LaserChemistry

答案:LaserMedicine；Physics；LaserBiology；LaserChemistryWhatarethepropertiesoflaserradiation?（）。

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

答案:Coherence(spatial,temporal).；Divergenceoflaserbeamissmall.；Polarization.；Laseremitsmonochromaticwave.Usuallylaseremitssinglewavelength.；Stimulatedemission.Theonethatcanexplaintheexperimentalcurveofblackbodyradiationperfectlyis（）

A:theRiley-PierceequationB:Einstein'sformulaC:Wien'sformulaD:Planck'sformula

答案:Planck'sformulaAconcavecavitywithaconcavemirrorofradiusRequaltothecavitylengthLisa（）.

A:StabilizingcavityB:UncertainC:unsteadycavityD:Criticalcavity

答案:CriticalcavityThewavelengthoftheCO2laseris（）

A:1064nmB:10.6μmC:335nmD:810nm

答案:10.6μmThebasicstructureofthelaserconsistsofelectricalworkingmatter,pumpsourceand（）threeparts.

A:OpticalresonantcavityB:ReflectorC:AffectedpoleD:Windowmirror

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

A:NeongasB:CarbondioxideC:CarbonmonoxideD:Oxygen

答案:Carbondioxide

第二章单元测试

Whattypeoflaserdoesthecarbondioxidelaserbelongto?（）

A:GaslaserB:FiberlaserC:Solid-statelaserD:Semiconductorlaser

答案:GaslaserWhenthepulseenergyiscertain,thenarrowerthepulsewidth,itmeansthetimeenergydensitywithtimeasthedenominator（）.

A:thesmallerB:UncertainC:ThegreaterD:Constant

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

A:B:C:D:

答案:Thefollowingstatementabouttheelectricfieldinductionformulaiscorrect（）。

A:P(z,x,y,t)ispolarizationofamediumB:ε(z,x,y,t)isdielectricpermittivityC:E(z,x,y,t)iselectricfieldstrengthD:all

答案:allWhatistheDuffing’sequationusedtocalculateelectrondisplacement?（）

A:B:C:D:

答案:Thethresholdconditionistheformationoflaser（）。

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

答案:sufficientnecessarycondition.Whenalaserpropagatesfromonemediumtoanotherwithadifferentrefractiveindex,a(C)willappearattheinterfacebetweenthemedia（）。

A:ReflectionandrefractionB:NeitherC:RefractionD:Reflections

答案:ReflectionandrefractionThecollisionalbroadeningspectrallineis（）。

A:ParabolictypeB:HyperbolictypeC:LorentzianlinearD:Gaussianlinetype

答案:LorentzianlinearParticlenumberreversaldistributionstatemicroscopicparticlessatisfy（）

A:FermidistributionB:GaussiandistributionC:BormanzdistributionD:Negativetemperaturedistribution

答案:NegativetemperaturedistributionAtacertaintemperature,theoddsofspontaneousradiationare（）timesgreaterthantheoddsofexcitedradiation

A:B:C:D:

答案:

第三章单元测试

TheDopplerbroadeningoftheCO2spectrallineis53MHz,andtheextremevalueofthespectrallinefunctioncorrespondingtothecentralfrequencyis（）。

A:1.7×109HzB:1.7×10HzC:1.7×10-9sD:1.7×10-9Hz

答案:1.7×10-9sQ-modulatedlaserscanusuallyobtain（）magnitudeshortpulses.

A:nsB:fsC:msD:μs

答案:nsRubylaserisatypical（）system。

A:ThreeenergylevelB:DienergylevelC:Multi-energylevelD:Four-energylevel

答案:ThreeenergylevelDopplerbroadeninghasoccurredin（）media.

A:IsolatesB:SolidsC:liquidsD:liquids

答案:liquidsHe-Nelasersbelongtothetypical（）system.

A:twoenergylevelsB:multi-energylevelC:threeenergylevelsD:fourenergylevels,

答案:fourenergylevels,Thecharacteristicsoflasercavityoscillationmodeare（）。

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

答案:Thedivergenceangleofthelaserbeamforeachmode.；Thesimpleharmonicfrequencyofthemode.；Theelectromagneticfieldtheoryofthemode.；Therelativepowerlossexperiencedbythemodeduringoneroundtripinthecavity.Forthesamemedium,thesmallsignalgaincoefficientvarieswith（）。

A:ExcitationpowerB:SpontaneousradiationchanceC:particlenumberdensityD:Spectrallinewidth

答案:ExcitationpowerNaturalbroadeningiscausedby（）.

A:collisionsofparticlesB:excitedstateshaveacertainlifetimeC:theDopplereffectD:vibrationofparticles

答案:excitedstateshaveacertainlifetimeTheresonantfrequencyofthelongitudinalmodeoftheresonantcavityis（）。

A:B:C:D:

答案:Symmetricconfocalcavitybasemodelightwaistfor（）。

A:B:C:D:

答案:

第四章单元测试

TherelationshipbetweentheEinsteincoefficientofspontaneousradiationandtheaveragelifetimeτoftheexcitedstateE2is（）。

A:B:C:D:

答案:Th