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简介:AstatisticalanalysisoftectonicenvironmentforM≥6.0strongearthquakesinChina'scontinentsincethebeginningofrecordedhistoryisperformedbasedonthedataofactivefaultsstudiedduringlast10yearsandresultofcompilationofthefourthversionoftheMapofSeismicRegionalizationofChinaforEarthquakeProtection.Tectonictypesofseismicsourcesofstrongearthquakesinallseismicregionsandthemovementmodesofseismogenicstructuresarediscussed.Meanwhile,ananalysisoflengthsofsurfacerupturezonesproducedbyalltypesofearthquakes,orientationsoflongaxesofmeizoseismalareas,regionaltectonicstressfieldsinseismicsourceregionsforstrongearthquakes,geophysicalfields(gravityanomaly,highconductivitylayeranomaly,andterrestrialheatflowdensity),andrecentverticalcrustaldeformationfieldshavebeencarriedout.
简介:TheeasternandwesternfrontsofplatemovementinTaiwanIslandandTibetanPlateaurespectivelyarethetwomajorsourcesoftectonicforceforthemorphogensisduringQuaternaryinChina'stropics.SevenexamplesofgeomorphologicaleffectsofplatemovementareenumeratedtodiscussthedifferentiationoftectoniclandformsinspaceandtimeduringQuaternary.ThetectonicmovementtendstobemoreactivesincemiddlePleistocene.Somephenomenasuchasthearc-shapemountainsystems,volcanismandcrustaldeformationimplythatthejuncturezoneofeasternandwesterntectonicforcesislocatedatabout110°E.
简介:SeismicPvelocitystructureisdeterminedfortheupper500kmoftheinnercoreandlowermost200kmoftheoutercorefromdifferentialtraveltimesandamplituderatios.ResultsconfirmtheexistenceofagloballyuniformFregionofreducedPvelocitygradientinthelowermostoutercore,consistentwithironenrichmentneartheboundaryofasolidifyinginnercore.Pvelocityoftheinnercorebetweenthelongitudes45oEand180oE(quasi-EasternHemisphere)isgreaterthanorequaltothatofanAK135-Freferencemodelwhereasthatbetween180oWand45oE(quasi-WesternHemisphere)islessthanthatofthereferencemodel.Observationofthisheterogeneitytoadepthof550kmbelowtheinnercoreandtheexistenceoftransitionsratherthansharpboundariesbetweenquasi-hemispheresfavoreithernoorveryslowinnercoresuperrotationoroscillationswithrespecttothemantle.DegreeoneseismicheterogeneitymaybebestexplainedbyactiveinnercorefreezingbeneaththeequatorialIndianOceandominatingstructureinthequasi-EasternHemisphereandinnercoremeltingbeneathequatorialPacificdominatingstructureinthequasi-WesternHemisphere.Variationsinwaveformsalsosuggesttheexistenceofsmaller-scale(1to100km)heterogeneity.
简介:Separationtechnologyofrareearthelements(REEs),asthecriticalstepintheseparationprocess,hadlongbeenfraughtwithtechnicaldifficulty.AresearchprojectconductedbyBaotouShiboRareEarthExtraction&EquipmentCo.Ltd.,BaotouREEResearchInstitute,andBaotouSteel&REEGroupHi-TechCo.Ltd(InnerMongolia),hassuccessfullysolvedtheproblemusingacentrifugalextractorandadvancedtechniquestoachieveakeybreakthrough.ThekeydeviceofthewholeproductionlinecontainsCTL-500FBcentrifugalextractorsanddigitalflowsystemequipment.Employmentofanautomaticcontrollingsystemanditsfullyfunctionaloperationsystem,alongwithvarioussupportivefacilities,fulfilstheseparationprocessesforvariousrareearthmaterials.Comparedwithconventionalbox-typeseparationtechnology,thisnewapproachsignificantlyimprovesthestirringintensity,thusimprovingproduction
简介:ThisworkinvestigatesthedistributionofhighwindsaboveBeaufortscale6intheoffshorezonesofChinausinghigh-resolutionsatellitemeasurements.AnumericalexperimentiscarriedoutinordertofindouttheeffectsofTaiwanIslandontheformationofstrongwinds.Theanalysisindicatesthatthedistributionofhighwindoccurrenceissimilartothatoftheaveragewindvelocityinwinter.Highwindstendtobeanchoredinspecialtopographicalregions,suchastheTaiwanStrait,theBashiChannelandthesoutheastcoastofVietnam.HighwindsoccurmuchmorefrequentlyoverthewarmerthanthecolderflankofKuroshiofrontasitmeandersfromTaiwantoJapan.Thefrequencyofhighwindsdecreasesdrasticallyinspring.TheTaiwanStraitmaintainsthelargesthighwindoccurrence.Besides,highwindsremainfrequentintheBashiChannel,thesoutheasttipofTaiwanIslandandthewarmerflankofKuroshiofront.Insummer,highwindsgenerallyoccurinfrequentlyexceptoverabroadregionoffthesoutheastcoastofVietnamnear10°Nandthefrequencytheredecreasesfromsouthwesttonortheast.HighwindsaroundTaiwanIslandpresentnearaxisymmetricdistributionwithlargerfrequencyalongsoutheast-northwestdirectionandsmallerfrequencyalongsouthwest-northeastdirection.Thedominantdirectionofhighwindsexhibitsacounterclockwisecirculationsurroundingtheisland.Thefrequencyofhighwindsincreasesrapidlyinautumnandalmostrepeatsthedistributionthatappearsinwinter.ThesimulationresultssuggestthattheeffectsofTaiwanIslandtopographyonhighwindsvarywithseasons.Inwinter,topographyisthemajorcauseofhighwindsinthesurroundingoceaniczones.HighwindsinbothTaiwanStraitandthesoutheastcorneroftheislanddisappearandthefrequencydecreasesgraduallyfromsouthtonorthwhentheterrainisremoved.However,insummer,highwindfrequencyderivedfromtwosimulationswithandwithoutterrainisalmostidentical.Weattributethisphenomenontothefactorswhicharerespon