简介：据说，赫鲁晓夫讲过一个关于苏联秘密警察的故事。

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简介：“Forcedlearning”referstothefactinChinathatsomestudentsareforcedtolearnbyparentsandteachers,regardlessoftheirownwishes.Sometimes,someparentsandteachersevenforcestudentstolearnthroughdisciplinaryactions.Specifically,studentsareimposedinthefollowingfouraspectsbyparentsandteachers:learningtime,learningcontents,learningfrequency,andlearningdifficulty,soitcausedbadconsequencesthatsomestudents’studytooktoomuchtime,coveredexcesscontents,isrepeatedtoomuchandistoodifficult.“Forcinglearning”destroyedthenatureofstudents,overdrewstudents’potential,andharmedstudents’physicalandmentalhealth.Inordertochangethisexistingsituationof“forcedlearning”,parentsandteachersshouldclarifythenatureofknowledgeandbroadenthewaystudentsacquireknowledge,activatestudents’innerstudymotive,andguidethemtolearnconsciouslyandactively,createaharmoniouseducationalenvironment,andmakefulluseofstudents’“children”nature;parentsandteachersstrengthencooperationtogivestudentsscientificguidanceonpsychology,emotion,andlearning.

简介：Inthispaper,thefrontogenesisforcedbydustradiativeheatingandtheradiativeeffectsofanisolatedduststorrnonafrontalcirculationsystemareexaminedbymeansoftwo-andthree-dimensionalnumericalmodels.Resultsindicatethatasaduststormbreaksout,frontogenesisiscausedinbydustradiativeheatingintheloweratmosphere.Amarkedisentropicpotentialtemperaturelayerisformedinthemiddletroposphere.Thelow-levelconvergenceoccursalongthedirectionofthefrontmovement.Atnight,dustradiativecoolingresultsinfrontolysisintheloweratmosphere.Anobviousverticalcirculationisforcedbyradiativeheatingofanisolatedduststormalongthedirectionofthepre-vailingwind.Itisstrongeratday,weakerandreverseatnight.Theresponseofthehorizontalwindfieldtodustradiativeforcingisdifferentatdifferentlevels.

简介：Theoreticalandexperimentalinvestigationsofheattransferinflatcurvilinearchannelhavebeencarriedout.Linearandnon-lineareffectsofDeanvortexesonintensityofheattransferweretakenintoaccount.Thelineareffect,whichdescribeharmonic(sinuous)variationoftheheattransfercoefficientneartheconcavesurfaceofthechannelandthenon-lineareffectcausesthegeneralincreaseoftheheattransfercoefficientduetoaugmentationofheattransferengenderedbytheDeanvortexes.Forbotheffects,mathematicalrelationswereobtainedintheformofquadratures.Thesenumericalresultsweremodifiedtotheformconvenientinengineeringcalculations.TheinvestigationshaveshownthatbothlinearandnonlinearcomponentsgrowupwiththeDeannumber.NonlinearcomponentQ0Tincreasesmoreabruptly,whilethelinearoneQ1Tismoreconservative.Thisisaconfirmationofstabilityofvortexstructures.

简介：Fiftyyearsago,theTibetansocietycomprisedserfsandslaves(referredtoasserfs),whoconstituted95percentofTibet’stotalpopulation,andthethreekindsofmanorlords(referredtoasserfowners),whoconstituted5％ofthetotalpopulation.Thethreemanorlordswereofficials(ofthelocalgovemment),feudallordsandtheupperstratumoftheclergy.TheyownedalllandinTibet(including

简介：Thispaperstudiesthecouplingeffectofthepipelinevibrationontheseabedscour.Averticaltwodimensionalmodelisappliedtonumericallyinvestigatethelocalscourbelowavibratingpipelinewithdifferentamplitudesandperiods.Usingthescourunderneathafixedpipelineasareference,thispaperfocusesontheimpactofthepipelinevibrationontheequilibriumscourdepth.Genericrelationshipsareestablishedbetweenthenon-dimensionalscourdepthandthenon-dimensionalvibratingparameters,i.e.,amplitudeandfrequency.Thenormalizationprocesstakesintoaccounttheinfluencesofsuchparametersastheincomingflowvelocity,pipediameter,andShieldsparameter.Anempiricalformulaisproposedtoquantifytheserelationships.

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简介：Abstract.Inthispaper,theforcedoddorderneutraldifferentialequationsoftheformarecon-sidered

简介：Inthispaper,wepresentanextensivestudyofthelinearlyforcedisotropicturbulence.Byusinganalyticalmethod,weidentifytwoparametricchoices,ofwhichtheyseemtobenewasfarasourknowledgegoes.WeprovethattheunderlyingnonlineardynamicalsystemforlinearlyforcedisotropicturbulenceisthegeneralcaseofacubicLienardequationwithlineardamping.WealsodiscussaFokker–Planckapproachtothisnewdynamicalsystem,whichisbistableandexhibitstwoasymmetricandasymptoticallystablestationaryprobabilitydensities.

简介：被动tracer的概率分布函数(PDF)，由“一个吝啬的坡度”强迫了，被学习。首先，我们采取二条理论途径，Lagrangian和有条件的闭合形式体系，到学习如此的外部地强迫的被动示踪物的PDF。然后，我们在一个范围上并且为测试吝啬坡度的模型是否能被用于学习在中间的纬度混合的同温层的tracer的同温层的风遨游的中等范围的天气预报(ECMWF)的欧洲中心为理想化的随机的流动执行数字模拟地区，在哪个，并且是否一弱并且杆病房带平均数的坡度被示踪物漏通过极、热带的混合障碍维持在中间的纬度的示踪物变化的PDF与理论预言一致。数字模拟证明当散开的驱散被吝啬坡度的强迫平衡时，在随机的PDF流动，在ECMWF风中的南部半球的PDF显示出时间不变的指数的尾巴，与理论预言一致。在北半球，PDF展出non-Gaussian尾巴。然而，PDF尾巴不与理论期望一致。强迫的示踪物的PDF尾巴的长期的行为与腐烂的tracer的相比。腐烂的示踪物的PDF尾巴是时间依赖者，这被发现，并且演变向恭维比指数。

简介：Theprimaryresonancesofaquadraticnonlinearsystemunderweakandstrongexternalexcitationsareinvestigatedwiththeemphasisonthecomparisonofdifferentanalyticalapproximateapproaches.Theforcedvibrationofsnap-throughmechanismistreatedasaquadraticnonlinearoscillator.TheLindstedt-Poincar′emethod,themultiple-scalemethod,theaveragingmethod,andtheharmonicbalancemethodareusedtodeterminetheamplitude-frequencyresponserelationshipsofthesteady-stateresponses.Itisdemonstratedthatthezeroth-orderharmoniccomponentsshouldbeaccountedintheapplicationoftheharmonicbalancemethod.Theanalyticalapproximationsarecomparedwiththenumericalintegrationsintermsofthefrequencyresponsecurvesandthephaseportraits.Supportedbythenumericalresults,theharmonicbalancemethodpredictsthatthequadraticnonlinearitybendsthefrequencyresponsecurvestotheleft.Iftheexcitationamplitudeisasecond-ordersmallquantityofthebookkeepingparameter,thesteady-stateresponsespredictedbythesecond-orderapproximationoftheLindstedtPoincar′emethodandthemultiple-scalemethodagreequalitativelywiththenumericalresults.Itisdemonstratedthatthequadraticnonlinearsystemimpliessofteningtypenonlinearityforanyquadraticnonlinearcoefficients.

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简介：<正>Inthispaper,weprovethattheforcedpendulum-typeequation+Gx（x,t）=p（t）,whereG（x,t）∈C1（R2）with1-periodicityinxsatisfiestheconditions:sup（x,t）∈R2|Gx（x,t）|<+∞andlimsupt→∞{supx∈R|（Gt（x,t））/t|}=0,possessesinfinitelymanyunboundedsolutionsonacylinderS1×Rforanyalmostperiodicfunctionp（t）withnonvauishingmeanvalue.

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简介：Thedynamiccharacteristicsofthelargescalecoherentstructuresinaforcedfreeshearlayerareexperi-mentallystudiedbymeansofflowvisualization.ThequantitativemeasurementsareacquiredbytheuseofaLDV.Itisshownthatthedevelopmentofthecoherentstructurescanbegreatlyinfluencedbyupstreamartificialperturbationsandasaresultthemixinginthelayercanbecontrolled.Likevortexmerging,vortexsplittingisalsoacommonevolu-tionpatterninthedevelopmentofthecoherentstructures.

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简介：Amathematicalmodelbasedonthetheoryofheatandmasstransferinporousmediawasdevelopedtosimulatetheevolutionofgraintemperatureandmoisturecontentinawheatstoragebinduringventilationwithcoolingairattheconstanttemperatureandhumidity.Unlikethepreviousworksonthisaspect,thepresentworkwasnotfocusedoncoolingthestoredgrainbyventilationwithambientair,butwiththerefrigeratedair.Validationwasperformedbycomparingbetweenpredictedandmeasuredgraintemperatureandgrainmoisturecontentfortwocases.Predicteddatawereinreasonablegoodagreementwithmeasuredones.Themodelandtheparametervaluesusedinthemodelareapplicableforpredictingtemperatureandmoistureofstoredgrainsunderventilationconditions.

简介：SignificantchangeshaveoccurredintheAntarcticPeninsula(AP)includingwarmertemperatures,acceleratedmeltingofglaciers,andbreakupoficeshelves.ThisstudyusestheWeatherResearchandForecastingmodel(WRF)forcedbytheCommunityClimateSystemModel4(CCSM)simulationstostudyfoehnwindwarminginAP.Wea-thersystemsresponsibleforgeneratingthefoehneventsaretwocyclonicsystemsthatmovetowardand/orcrossoverAP.WRFsimulatesthemovementofcyclonicsystemsandtheresultingfoehnwindwarmingthatisabsentinCCSM.ItisfoundthatthewarmingextentalongatransectacrossthecentralAPtowardLarsenCIceShelf(LCIS)variesduringthesimulationperiodandthemaximumwarmingmovesfromnearthebaseofleewardslopestoover40kmawayextendingtowardtheattachedLCIS.Ouranalysissuggeststhatthefoehnwindwarmingisnegativelycorrelatedwiththeincomingairtemperatureandthemountaintoptemperatureduringperiodswithoutsignificantprecipitation,inwhichisentropicdrawdownisthedominantheatingmechanism.Ontheotherhand,whensignificantprecipitationoccursalongthewindwardsideofAP,latentheatingisthemajorheatingmechanismevidencedbypositiverelationsbetweenthefoehnwindwarmingand1)incomingairtemperature,2)windwardprecipitation,and3)latentheating.Foehnwindwarmingcausedbyisentropicdrawdownalsotendstobestrongerthanthatcausedbylatentheating.ComparisonofWRFsimulationsforcedbyoriginalandcorrectedCCSMdataindicatesthatfoehnwindwarmingisstrongerintheoriginalCCSMforcedsimulationwhennosignificantwindwardprecipitationispresent.Thefoehnwindwarmingbecomesweakerinbothsimulationswhenthereissignificantwindwardprecipitation.Thissuggeststhatmodel’sabilitytoresolvethefoehnwarmingvarieswiththeforcingdata,buttheprecipitationimpactontheleewardwarmingisconsistent.