简介:高分辨率的浅地震方法是在近的表面描述的最广泛地使用的地球物理的方法。然而,在许多情况中,解释地震图象能是似是而非的。在这篇文章,我们在场因为不适当的限制,源于表面波浪(MASW)的地震思考,嘘波浪地震思考,和多信道的分析调查的P波浪的三案例研究不正确地在调查地点表面或表面下的条件上被解释。一个P波浪思考调查特征首先作为一个浅差错地区被解释,但是当获得通过了道路交叉,它以后决心源于背景噪音的高水平。一个嘘波浪地震思考调查特征被解释是一个反向的蘸滑倒差错,但是指向钻证明它是进基岩表面的深本地的侵蚀。在MASW调查,最后,一个陡峭地蘸的特征首先作为一条基岩山谷被解释。然而,以后探索的钻显示了特征是严重地抑制了大多数应用表面波浪频率乐队的很软的湖沉积的浅层。尽管起始的解释是不正确的,他们在地球物理学者和地质学家之中刺激了讨论并且以前为在科学家之间的有意义的合作和讲话强调了需要,在期间,并且在地球物理的数据获得以后。
简介:—Inthispaper,anonlinearmodelispresentedtodescribewavetransformationinshallowwat-erwiththezero-vorticityequationofwave-numbervectorandenergyconservationequation.Thenonlineareffectduetoanempiricaldispersionrelation(byHedges)iscomparedwiththatofDalrymple'sdispersionrelation.Themodelistestedagainstthelaboratorymeasurementsforthecaseofasubmergedellipticalshoalonaslopebeach,wherebothrefractionanddiffractionaresignificant.Thecomputationre-sults,comparedwiththoseobtainedthroughlineardispersionrelation.showthatthenonlineareffectofwavetransformationinshallowwaterisimportant.Andtheempiricaldispersionrelationissuitableforre-searchingthenonlinearityofwaveinshallowwater.
简介:Basedonthehydrodynamicalfeatureandthetheoreticalvelocityprofilesoftidalflowandwind-inducedflowinshal-lowsea,acomputationalmodelisestablishedforthefirsttime,whichcanseparateobservedvelocityintotidalvelocityandwind-inducedvelocitybyuseoftheleastsquaremethod.Withthemodel,notonlythesurfacevelocitiesoftidalflowandwind-inducedflowareobtained,butalsothebedroughnessheightisdeterminedandthewindvelocityabovethewa-tersurfaceisestimated.Forverificationofthemodel,theobservedvelocityintheYellowRiverEstuaryandthelaborato-rytestisseparated,thenitisappliedtotheYangtzeRiverEstuary.Alltheresultsaresatisfactory.Theresearchresultsshowthatthemodelissimpleinmethod,feasibleinprocessandreasonableinresult.Themodelisavalidapproachtoanalysisandcomputationoffielddata,andcanbeappliedtoseparatetheobservedvelocityinshallowsea;atthesametime,reasonableboundaryconditionsofthesurfaceandbottomcanbeobtainedfortwo-andthree-dimensionalnumericalsimulation.
简介:Athree-dimensionalnumericalmodel,EFDC(environmentalfluiddynamicscode)isappliedtothePamlicoRiverEstuary(PRE)ineasternNorthCarolinaoftheUnitedStatestoexaminethewindimpactonpollutantagedistributionsandresidencetime.Aseriesofmodelexperimentsrepresentingbasecase,remote-wind-inducedwaterlevelset-upandlocalwindscasesareconducted.ModelresultsindicatethatthepollutantmeanageandthesystemresidencetimearefunctionsofgravitationalcirculationinthePRE.Thesystemresponsestoremote-wind-inducedwaterlevelset-uparedifferentindifferentportionsofthePRE.Undersuchcondition,dissolvedsubstancesintheupstreamportionofthePREhaveayoungerageandshorterresidencetime(comparedwiththebasecase),bycontrast,theyhaveaolderageandlongerresidencetimeinthedownstreamportionofthePRE.Upriveranddownriverlocalwindsappeartohaveoppositeimpactsonpollutantagedistributions.ThesubstancesareretainedmuchlongerwithinthePREunderupriverwindthanthoseunderdownriverwind.Themodelresultsalsosuggestthatacross-riverwindsmayleadtolongerresidencetimethroughenhancedturbulencemixing,whichslowsdownthegravitationalcirculationinthePRE.
简介:摘要:课堂是实施教学的主要阵地,要想提高学生的学习效果,抓好课堂教学十分关键。互动式课堂教学是新型的课堂教学模式,互动的课堂具有真实性、开放性及多维性,是学生与学生、学生与教师之间的对话过程。在小学数学互动式课堂教学中教师应充分发挥出主导作用,鼓励每一个学生都参与到课堂教学活动中,最大限度地提高课堂教学效果。