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126 个结果
  • 简介:TheYangtzeRiveristhelargestriverinChina,about6,300kilometreslongwithadrainageareaandpopulationaccountingfor18.8percentand33percentrespectivelyinChina.AimingatincreasingforestandvegetationareasonthemiddleandupperreachesoftheYangtzeRivertocontrolwaterandsoilerosion,theChinesegovernmentin1989decidedtocommenceaconstructionprojectfortheprotectionoftheforestsystemonthemiddleandupperreachesoftheYangtzeRiver.Theprojectcovers645counties(citiesanddistricts)in13provinces,

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  • 简介:<正>WiththerecentannouncementofthewaternowrisingbehindthemassiveThreeGorgesDam(SanxiaBa),IwasremindedofmyjourneydowntheLongRiveratatimewhenthedamwasunderconstructionandthemanycommunitiesalongtheriverstillexistedastheyhaddoneforhundredsofyears.TodaytheregionisattheheartofChina’smodernisationdriveandwillplayWiththerecentannouncementofthewaternowrisingbehindthemassiveThreeGorgesDam(SanxiaBa),IwasremindedofmyjourneydowntheLongRiveratatimewhenthedamwasunderconstructionandthemanycommunitiesalongtheriverstillexistedastheyhaddoneforhundredsofyears.TodaytheregionisattheheartofChina’smodernisationdriveandwillplay

  • 标签: hundreds river behind JOURNEY ANNOUNCEMENT BAMBOO
  • 简介:ThecharacteristicsoftheTriassicsequencesdevelopedintheLowerYangtzeareadisplaysomegreatchangesinbothenvironmentandclimate.Thechangeofenvironmentwasatransitionfrommarinetocontinentviaalternatingenvironments.Thechangeofclimatewasatransitionfromtropic(torrid)towarmandwetclimateviasubtropicdryclimate.Thetypevariationsofthesequenceswerefromthemarinesequencestothecontinentalsequences,correspondingtothechangesofenvironmentsandclimates.Sequence1isatypeⅡofsequenceofmixedclasticandcarbonatesediments;sequence2isatypeⅠofsequenceofcarbonateplatform;sequence3isatypeⅠofsequenceofcarbonatetidalflat-saltlagoon,sequence4isatypeⅡofsequenceoflacustrinewithinmarinelayers,andsequence5isasequenceoflacustrine-swamp.Thedevelopment,distributionandpreservationofthosesequencesrevealthetectoniccontrolsandtheirchangesinthebackground.ThecollisionbetweentheYangtzeplateandtheNorthChinaplatewasagreatgeologicaleventinthegeologicalhistory,butthetimingofthecollisionisstilldisputed.However,thecharacteristicsofTriassicsequencestratigraphyandsealevelchangesintheLowerYangtzearearespondedtothiscoliision.ThecollisionstartedatthebeginningofmiddleTriassicandthegreatregressionintheLowerYangtzeareastarted22Maearlierthanthoseintheworld.Thetectonicconditionsoccurredbeforeandduringthecollisioncontrolledthedevelopmentofsequencesandtypechanges.

  • 标签: 三叠纪 序列 气候 构造运动 沉积岩
  • 简介:Theexploitablepotentialofhydropowerresourcesinthe1,800,000km~2Yangtzebasinis197GW,correspondingtoanannualelectricitygenerationof1030TWh,whiletheupperYangtzeupstreamofthecityYichangwithdrainageareaof1,000,000km~2possessesanexploitablepotentialofhydropowerresourcesof170GWor85%ofwhatisinthewholeYangtzebasin,asriverchannelsofthemainstemandtributariesinuppeYangtzepassthroughhighmountains,plateausandhills.

  • 标签: YANGTZE ELECTRICITY installed river drainage reservoir
  • 简介:ThehydrodynamicandthesedimenttransportpatternswithintheestuaryoftheYangtzeRiverarecomplexbecauseofinteractionoffluvialandthetidalforces,dependingonfreshwaterdischargeandtidalrange.Basedonthedatameasuredinrecentyears,thispaperdiscussesthecharacteristicsofflowandsedimentmovementintheYangtzeRiverEstuaryandtheirinfluencesontheevolutionoftheestuary.

  • 标签: YANGTZE RIVER Estuary Sediment transport TIDAL
  • 简介:Theso-called“Yangtze-type”copperdepositsinclude:(1)Cu-bearingmassivepyritebed,(2)Cu-bearingskarnandmagnetite-typeoredeposits,withreplacementCu-vein-typedepositsnearthemetasomaticzone,and(3)mineralizedintrusivebodiesandbrecciapipes,someofwhichareknownasporphyrycopperores(e.g.Chengmenshan).ThistypeoforedepositsisatypicalexampletoverifythepolygenesisofinostofthedepositsinChina,ashasbeenpromotedbyProf.TuGuangchiinviewofthepolycyclicdevelopmentofthegeologicalhistoryinChina.Thispaperiscon-cemedwithonesub-typeofsuchdeposits.

  • 标签: 铜矿床 沉积环境 黄铁矿 成矿作用 成因 硫同位素
  • 简介:<正>NanjingNO.2YangtzeRiverBridgewasanationalkeyconstructionprojectduringtheNinthFive-YearPlanperiod(1995-2000).Itislocated11kilometresupstreamfromthefirstYangtze

  • 标签: YANGTZE NANJING UPSTREAM Hangzhou AHEAD smoothly
  • 简介:BasedonthebiogeochemicalstudiesonnutrientelementsintheChangjiangestuary,themainresultsandrecentprogressesarereviewedinthispaper,suchasthenutrientfluxesintothesea,themixingbehaviors,thedistributioncharacteristicsandtransportationaswellasthebiogeochemicalbehaviorsofnutrientsintheplumefrontalregion.Theexploringdirectionsandresearchemphasesinthefutureareproposed.

  • 标签: 生物地球化学 营养元素 长江 入口处
  • 简介:Threefundamentaltheoriesareraisedfor“complexityandself-organizedcriticality(SOC)ofmetalogenicdynamicsystems”(Yu,1998):(1)Nonl...

  • 标签: self organized CRITICALITY (SOC) EDGE of
  • 简介:GreendevelopmentisthekeynoteofYangtzeRiverEconomicBelt.Itmustinsistonecologypreferentialandgreendevelopmentwhichisnotonlyrespectationofnaturallawsbutalsotheeconomiclawsandsociallaws.ThearticleusesSWOTanalyticmethodtoanalyzetheinternalandexternalsurroundingsofthegreendevelopmentofYangtzeRiverEconomicBeltonthebasisofgettingaclearunderstandingofitspresentdevelopingstatus.BasedonthisthearticleputsforwardthestrategypatternandpathselectionofgreendevelopmentofYangtzeRiverEconomicBelt.

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  • 简介:ThecircumfluencearoundtheJiuduanSandbankisthoroughlystudiedbymeansoftheprinci-pleofleastresistanceinfluiddynamics.ThediversionratiooftheNorthChannelfor1998iscalculated,whichisalmostthesameasthefieldsurveydata.ThenormalandminimumdiversionratiosoftheNorthChannelafterstagesⅠ,ⅡandⅢregulationworksaswellasthefuturephaseareobtained.Thenumeri-calresultsandpredictedvalueareaccurate.

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  • 简介:-ThispaperdescribesaradioactivetracerexperimentcarriedoutatthelandwardspoilsiteoftheNorthPassageintheYangtzeEstuaryinJune,1991.Scandium-46wasselectedasthetracer,thetotalactivityreleasedwas179.45GBqandtheamountoftheSandium-46glasswas495g.Thepurposeoftheexperimentwastodeterminethesedimentmovementdirection,path,velocityandtransportrate,andtherefore,toprovidedirectevidenceforusingthelandwardspoilsiteinthefuture.Theexperimentalresultsshowedthatthesedimentmovementwasgovernedbytheebbtidecurrentduringtheperiodofmeanandneaptideswhentheradioactivetracerwasinjectedbothonthefloodandebbtides,andthesedimentmovedfromthereleasepointtothemiddleoftheNorthPassagenearnavigationbuoyNo.269.Thedirecitonofthesedimentmovementwas110°,theparticlevelocitywas758m/d,andthesedimenttransportrateperunitwidthwas47.8m3/md.

  • 标签: RADIOACTIVE TRACER SEDIMENT transport ESTUARY injection
  • 简介:MultistagesuperimposeddeformationhasbeendiscussedsystematicallybasedontheprogressofthestratigraphicsequencesofthenortheasternmarginofYangtzeBlock.Thenew-discoveredfirststagedeformationofthosesequencesoccurredfromthemiddleTriassictotheendofearlyJurassictogetherwithdevelopmentofregionalfolding,whichwasresultedfromthedeepdetachmentshearingtendingtowardNW-WNW.Thefoldsdiptoeastandfalldowntowardwest,andweresuperimposedbythemainstagefolding.Thereafter,aseriesoffoldsweredevelopedwithaxestrendingtowardnortheast.Consequentlynormalfoldsoccurredonthenormallimbswhileoverturnedfoldontheoverturnedlimbsduringthefirststagefolding.ThedetachmentorthrustwasformedfromlateJurassictoearlyCretaceous.DuetotheupliftingofDabieandtheWannanMountainsinthenorthandsouthsides,thebi-directionalthrustingbeltwasformedbygravityflowingfromtheMountainstowardthecenterofthebasinalongthenorthsideofXuanchengandsouthsideofGuichi.Thedeformationgeodynamicswasdiscussedsimplybasedonthenewlyrecognizedinformationaboutthetectonicevolution.

  • 标签: 中国 长江下游东北部板块 多级叠加变形 重力滑动 冲断层
  • 简介:Throughoneandhalfyearcontinuousin-situmeasurements,thedistributionsandvariationsofsurfaceozoneanditsprecursorsatatypicalmixedagriculturalandmetropolitanarea-Changshu,YangtzeDeltaregion,werestudied.Thepreliminaryanalysisontheconcentrationlevelsandvariationsofsurfaceozoneindicatedtheobviousseasonalanddiurnalcyclesduringtheexperiment.Thehourlyaveragedconcentrationsofsurfaceozonewerehigh,inabout17%oftotalvalidhoursthesurfaceozoneconcentrationexceeded50ppb,andin22daysthehourlyaveragedozoneconcentrationwasgreaterthan100ppb.Therewereabout40%ofthedaysinthatthedailymaximum8-hourozoneconcentrationwasgreaterthan50ppb.Thedayswithdailymaximum8-hourozoneconcentrationgreaterthan80ppbwereabout33daysthataccountedforabout8%oftheobservationaldays.Thevariationsof5-daymovingaveragedozoneconcentrationsdependedbothontheweatherconditionsandonthechangesofozoneinbackgroundatmosphere.Photochemicalprocesshadthesignificantimpactsonozoneproductions.

  • 标签: TYPICAL mixed agricultural and METROPOLITAN area
  • 简介:长江三角洲(UA-YRD)上的城市的凝块在水,土地,生态的环境,地点和交通的方面有一些优点。依靠资源环境库和另外的优点,UA-YRD完成了大开发。基于索引系统和全面评估的模型,自从1978,纸计算UA-YRD的发展水平。从1978~2007,开发水平以0.0333的年度率逐年增加了的结果表演,和开发的进程能被划分成三个阶段,即低速度的开发舞台(19781991),快速的开发舞台(19912000),并且高速度的开发舞台(20002007)。速度分别地是0.0083,0.0356和0.0766。在30年的发展期间,外国经济活动在开发有最大的效果,由交通,工业经济活动和电信列在后面(有序)。另外,不同驱动力在不同阶段有不同效果。纸建议更多的注意应该对高速度的发展阶段和重要驱动力被给予驾驶它的发展。同时,资源和环境的限制不应该被忽视,长有效的机制需要被证实在UA发展,资源利用和环境保护之中支撑和谐开发。一些比较研究应该着急地被执行有效地支持并且支持UA的持续开发,特别向进化,驱动力和braking力量。

  • 标签: 长江三角洲 城市群 优势 综合评价指标体系 生态环境 资源环境