简介：Ｏｎｔｈｅｂａｓｉｓｏｆｐｒｅｖｉｏｕｓｒｅｓｅａｒｃｈａｎｄｐｒａｃｔｉｃｅ，ａｎｅｗｍｏｄｅｌｓａｎｄＢＺＹｈａｓｂｅｅｎｓｕｃｃｅｓｓｆｕｌｌｙｄｅｖｅｌｏｐｅｄ．Ｅｘｐｅｒｉｍｅｎｔｓｈａｖｅｂｅｅｎｃａｒｒｉｅｄｏｕｔｏｎｉｔｓｐｒｏｐｅｒｔｉｅｓ，ｉｎｃｌｕｄｉｎｇｕｎｉｔｗｅｉｇｈｔ，ｉｎｉｔｉａｔｉｏｎｖｅｌｏｃｉｔｙ，ｓｅｔｔｌｉｎｇｖｅｌｏｃｉｔｙ，ｒｅｐｏｓｅａｎｇｌｅ，ｅｔｃ．ＴｈｅｅｘｐｅｒｉｍｅｎｔｓｓｈｏｗｔｈａｔｔｈｅＢＺＹｍｏｄｅｌｓａｎｄｈａｓｍａｎｙｍｅｒｉｔｓｏｖｅｒｏｔｈｅｒｓ，ｓｕｃｈａｓａｄｊｕｓｔａｂｌｅｕｎｉｔｗｅｉｇｈｔ，ｗｉｄｅｒａｎｇｅｏｆｐａｒｔｉｃｌｅｓｉｚｅ，ｐａｒｔｉｃｌｅｓｈａｐｅｓｉｍｉｌａｒｔｏｎａｔｕｒａｌｓａｎｄａｎｄｓｔａｂｌｅｐｈｙｓｉｃａｌａｎｄｃｈｅｍｉｃａｌｐｒｏｐｅｒｔｉｅｓ．Ｔｈｕｓｉｔｈａｓｈｉｇｈｖａｌｕｅｆｏｒｓｔｕｄｙ，ｄｅｖｅｌｏｐｍｅｎｔａｎｄｅｘｔｅｎｓｉｏｎｆｏｒａｐｐｌｉｃａｔｉｏｎ．Ｓｔｉｌｌｓｏｍｅｏｆｉｔｓｐｒｏｐｅｒｔｉｅｓｎｅｅｄｔｏｂｅｆｕｒｔｈｅｒｓｔｕｄｉｅｄ

简介：Experimentalstudyoninitiationofbivalveshellmotiononahorizontalsandbed,underaunidirectionalflowofwater,ispresented.Experimentswerecarriedoutinaflumewiththreetypesofbivalveshells,namelyCoquinaClam,Cross-barredChioneandPonderousArk,totesttheconditionforinitiationofmotion.Theshapeparametersofbivalveshellsaredefinedappropriately.Experimentswereconductedinaflumewithahorizontalbed,andthecriticalshearstresseswereestimatedusingVanoni'sside-wallcorrection.Thecharacteristicparametersaffectingtheinitiationofshellmotiononahorizontalbedinrough-turbulentregimeidentifiedbasedonthephysicalreasoninganddimensionalanalysisaretheShieldsparameter(nondimensionalcriticalshearstress),nondimensionalcompetentmeanvelocity,nondimensionalsandroughness,nondimensionalflowdepthandshapeparameter.EquationsofShieldsparameterandnondimensionalcompetentmeanvelocityfortheinitialmovementofshellsonahorizontalsandbedwithconvexupwardanddownwardconditionsareobtainedusingexperimentaldata.

简介：Theresultsofastudyonthekeytechnologyofusingshellsand,akindofseasand,asbackfillforseareclamationaredescribedbriefly.Laboratorytestsshowthatthephysicalandmechanicalpropertiesofshellsandareasgoodasnormalquartzsand.Basedonthechemicaltestanddurabilitytestofshellsanditcouldbeconcludedthattheinfluenceofcorrosionofshellsandbyacidrainandseawatermightbeignoredintheevaluationofthesafetyanddurabilityoftheengineeringproject.Theresultsoffieldimprovementtestsshowthatthebearingcapacityofshellsandbackfillfoundationismorethan200kPaaftervibroflotationimprovementordynamiccompactionimprovement.Theshellsandisagoodbackfillmaterialforseareclamation.

简介：Ｔｈｅ　ｍｏｄｅｒｎ　ｃｈａｎｇｅ　ａｎｄ　ｅｖｏｌｕｔｉｏｎ　ｔｅｎｄｅｎｃｙ　ｏｆ　ｓａｎｄ　ｃｏａｓｔ　ｉｎ　ｔｈｅ　ｅａｓｔｅｒｎ　ａｒｅａ　ｏｆ　Ｌｉａｏｄｏｎｇ　ＧｕｌｆＭｉａｏＦｅｎｇｍｉｎ；ＢｉＺｈａｏｑｉ；ＬｉＳｈｕｙｕａｎ；Ｘｉａ...

简介：ShanghaiislocatedineasternChinaandisbuiltonoverburdensoillayers.ItcanbeseenfromtheMexicoMs=8.1earthquakeonSeptember19,1985andtheHanshinMs=7.4earthquakeonJanuary17,1995thatheavycasualtiesandpropertylosseshaveadirectrelationshipwithoverburdensoillayers.Groundmotionscausedbyearthquakesaresignifieantlyamplifiedwhenpassingthroughthesoillayers.Undertheinfluenceoftheseamplifiedmotions,buildingstructures,whosenaturefrequencyiswithinthefrequencybandofsoilamplificationresponse,willexperiencemoreseveredamagethanthosebuiltonbedrock.Therefore,engineeringseismologistshavepaidconsiderableattentiontheamplificationresponsesintheShanghaioverburdensoillayers.TheamplificationresponsesofsoilandsandlayersinthispaperaregivenbytheML=4.1earthquakeinNantong,JiangsuProvinceonDecember25,2001at31.8°N,120.9°E.Itcanbeseenthattheresponsesofsoilandsandlayersareverydifferent.Thatisimportant.

简介：“Ejin节”在调查的EjinOasiswas在一个典型盖住植被的沙丘发现了。在这研究，263件样品为谷物尺寸分析从节被拿，25for化学药品分析，11为~(14)标明日期的C并且6为扫描电子显微镜(SEM)。学习的Theresults显示在节的沉积的3种类型能被识别，YS，LSand圣伊斯，同类的黄褐的沙丘沙，等于内陆沙漠的那些，LS，像黄土的砂土，与在中间的沙的黄土一样黄河和现代掉落灰尘，和圣，沙的沉积内部有Tamarixspp的枯枝和落叶的beded，代表突然的变化在气候打断的节的depositional过程。自从2500年BP和灰尘暴风雨的高峰时期，TheEjin节记录了重复灰尘暴风雨或沙暴或节揭示的沙暴在历史的文学与“灰尘雨”的记录一致，显示气候的变化是增加沙暴或灰尘暴风雨的一个关键因素，而，“人工”的因素可以仅仅是加速的fordesertification。

简介：Thetypicalblackstormsorsand-duststormsinthenorthwesternChinaaregeneratedanddevelopedthroughaninteractionbetweenthespecificlargescalecirculationpatternandmesosealesystems.Thepassingby/overahugesand-abundantdesertofastrongcoldfrontwithintensivefrontalzoneatmidandlowerlevelsisanecessaryconditionfortheformationanddevelopmentofablackstormoraseveresand-duststorm.Inordertoinvestigatethemechanismofthesand-dustmobilization,transportandsedimentationduringtheblackorsand-duststorms,aparameterizationschemeofsand-dustsource-sinktermsandanequationoftransportforthesand-dustwereproposedandincorporatedintotheMM4mesoscalemodel.ThemodifiedMM4modelwasappliedtothe“May1993”blackstormcaseandsucceededinreproducingtheevolutionoftheweathersystemsassociatedwiththeblack-storm,thesand-dustconcentrationatsurfacelayeranditsverticaldistribution,andthesand-dustsedimentationandtransport.Ourresultsshowthatthenumericalsimulatingmethodbyusingamesoscalemodel,withinclusionofanequationofthesand-dusttransportandaparameterizationschemeofthesand-dustsource-sinkterms,isapromisingapproachtostudythemechanismforsand-dustmobilization,transportandsedimentationduringasand-duststormevent.

简介：Sand-duststormisaspecialnaturaldisasterthatfrequentlyoccursindesertsandtheirsurroundingareas.WiththedatapublishedonSurfaceMeteorologicalMonthlyBulletinandSurfaceChartduring1971-1996,thetemporal-spatialdistributionandannualvariationofsand-duststormsareanalyzedonthebasisofthecasestudyofatmosphericprocesses.Furthermore,thetracksandsourceareasofsand-duststormsaredeterminedwiththeaidofGIS.TheresultsshowthatexceptsomepartsofQinghaiProvinceandInnerMongoliaaswellasBeijing,sand-duststormsdecreaseapparentlyintimeandspaceinrecentdecadesinChina.Sand-duststormsoccurmostfrequentlyinspring,especiallyinApril.Accordingtotheirsourceareas,sand-duststormsareclassifiedintotwotypes,i.e.,theinner-sourceandouter-sourcesand-duststorms.Mostoftheouter-sourcesand-duststormsmovealongthenorthandwesttracks.Thenorth-trackouter-sourcesand-duststormsalwaysintrudeintoChinaacrosstheSino-MongolianborderfromHami,acityintheeasternpartofXinjiang,toXilinGol,aleagueinInnerMongolia,whilethewest-trackonesintrudeintoChinafrombothsouthernandnorthernXinjiang.Thesourcelandsofinner-sourcesand-duststormsconcentrateintheTaklimakanDesertanditssurroundingareasinsouthernXinjiang,southernpartoftheJunggarBasininnorthofXinjiang,theHexiCorridorinwesternGansuProvince,thedrydesertsofInnerMongoliaandtheQaidamBasininQinghai.

简介：Theformationofsandwaveissuchaprocessinwhichtheroughnessanddiscontinuityoftheoriginalbedsurfacecausethedisturbanceofthebottomlaminarflowinanopenchannel,andthedevelopmentofthedisturbanceinturnleadstoinstabilityoftheflowandtheappearanceofthecoherentstructure.Theevolutionanddevelopmentofthecoherentstructurefurtherpromotetheundulationsofbedsurfaceandsandwavesrisefinally.Thesandwaveisexplainedasaresultofactionthatthebedsedimentparticlesaredisturbedbythecoherentstructure.Thisstudyshowsthatthesandwaveformationistheresultofdisturbanceactionofneutralcoherentstructure,andthesandwaveshapeobtainedincomputationsisidenticaltothepracticalone.