简介：AninvestigationofmacrobenthosinthelittoralzonewascarriedoutinTangguDistrict,TianjinCityinJune2003.Thisinvestigationwastheonlyintegratedonesince1983there.Somethingaboutmacrobenthosinvestigationwasreportedinthispaper.Theresultsshowedthatthebiomassofmacrobenthosofthatareawasalmostatthesamelevelasthatof1983,andthedensityofmacrobenthosincreasedalittle.ThebiomassofMactraveneriformishasgreateffectontheaveragebiomassofthatarea.Thediversityofmacrobenthoshaschangedobviously,and5or6kindsofmacrobenthoshavebecomeextinctordecreasedgreatly.Sotheecologicalstructureofmacrobenthoshasbecomesimplerandunstable.Inaddition,someecologicalmethodstoremedytheareaarediscussedinthispaper.

简介：Xiangshanbayisanarrowsemi-closedbayandsituatedonthenorthwesterncoastoftheEastChinaSea.Overpastdecades,ithasbecometoamajorbaywithintensivehumanactivities,denseurbanizedarea,andpoorwaterquality.Theaimofthispaperwastorevealtheecologicalstatusthroughtheelucidationofthespeciescomposition,abundance,biomassanddiversityofmacrobenthosinthisbay.SixintertidalsectionsweresurveyedfromJanuary2007toNovember2008quarterly.SectionsTG,HDandXHarelocatedinthethreeinnerbays,sectionsQJandWSarelocatednearthethermalpowerplants,andsectionXXislocatedattheouterpartofXiangshanBay.Greatvariationsinmacrobenthoscommunitywereindentified,andthespeciescompositionofthecommunityinthepresentstudyshowedthedominanceintheorderofmolluscs(bivalvesandgastropods),crustaceansandothers,andonlyfewPolychaetawererecorded.Onlythreedominantspecies,Littorinabrevicula,Ilyplaxtansuiensis,andCerithideacingulatawerecollectedinallthesections,andatotalof19dominantspecieswererecordedonlyinonesection.Two-wayANOVAanalysesofabundanceindicatedthatthereweresignificantdifferencesamongsectionsorseasons.Shannon-Wienerdiversityindex(H’)haditsmaximum(2.45)insectionQJ,andminimum(1.76)insectionTG.Multipleirregulark-dominanceplotsclearlyshowedthatthestudyareawaspollutedandthemacrobenthoscommunitywasunderstress.WeconcludethatthemacrobenthosofXiangshanBayhavebeendisturbedbyhumanactivities,especiallyattheinteriorbay.

简介：Athree-dimensional(3-D)oceanmodeliscoupledwithatwo-dimensional(2-D)seaicemodel,torevisitanonlinearadvectionmechanism,oneofthemostimportantmesoscaleeddygenesismechanismsinthemarginalicezone.Two-dimensionaloceanmodelsimulationssuggestnonlinearadvectionmechanismismoreimportantwhenthewatergetsshallower.Insteadofconsideringtheoceanasbarotropicfluidinthe2-Doceanmodel,the3-Doceanmodelallowstheseaicetoaffectthecurrentdirectlyinthesurfacelayerviaocean-iceinteraction.Itisfoundthatbothmesoscaleeddyandseasurfaceelevationaresensitivetochangesinawaterdepthinthe3-Dsimulations.Theverticalprofileofacurrentvelocityin3-Dexperimentssuggeststhatwhenthewaterdepthgetsshallower,thecurrentmovefasterineachlayer,whichmakestheseasurfaceelevationbenearlyinverseproportionaltothewaterdepthwiththesamewindforcingduringthesametime.Itisalsofoundthatbecauseoftheverticalmotion,themagnitudeofvariationsintheseasurfaceelevationinthe3-Dsimulationsisverysmall,beingonly1%ofthechangeinthe2-Dsimulations.Anditseemstheverticalmotiontobetheessentialreasonforthedifferencesbetweenthe3-Dand2-Dexperiments.

简介：Iceloadisthedominativeloadinthedesignofoffshoreplatformsintheicezone,andtheextremeiceloadisthekeyfactorthataffectsthesafetyofplatforms.ThepresentpaperstudiesthestatisticalpropertiesoftheglobalresistanceandtheextremeresponsesofthejacketplatformsinBohaiBay,consideringtherandomnessoficeload,deadload,steelelasticmodulus,yieldstrengthandstructuralmemberdimensions.Then,basedontheaboveresults,anefficientapproximatemethodoftheglobalreliabilityanalysisfortheoffshoreplatformsisproposed,whichconvertstheimplicitnonlinearperformancefunctionintheconventionalreliabilityanalysistolinearexplicitone.Finally,numericalexamplesofJZ20-2MSW,JZ20-2NWandJZ20-2MUQoffshorejacketplatformsintheBohaiBaydemonstratethesatisfyingefficiency,accuracyandapplicabilityoftheproposedmethod.