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简介：河口沼泽地用作一个自然障碍移开产生陆地的污染物质并且从陆地稀释污染物质负担到海。作为最重要的河口沼泽地之一，Yangtze河口沼泽地吸引了特别inte

简介：BasedontheABAQUSexplicitdynamicsimulationplatform,thefiniteelementmodelofsinglestandmillwithrestrainedmandrelwasadoptedtoresearchtheinfluenceofmandrel-rollervelocityratio(MRVR),mandrelfrictionandtensionbetweenstandsonrollingforce.TheanalysisresultsshowthatwhentheMRVRislowerthan1,therollingforceincreasesobviouslywiththeincreaseofMRVRandreachesthepeakvaluewhentheMRVRisabout1.TherollingforceincreaseinducedbytheMRVRincreaseisthemainreasonoftheformationofthebulgedefectonthetubeheadandtailattheenteringandexitingstageduringtubecontinuousrollingprocessbyfullfloatingmandrelmill,whichcanbeintensifiedbytheincreaseofmandrelfrictioncoefficient.Therollingforcedecreaseswiththeincreaseoftension.Asthetensionislarger,therollingforcedecreaseamplitudeislarger.Theinfluenceofbackwardtensiononrollingforceisgreaterthanthatofforwardtensiondistinctly.TensioncontrolcanbeusedtodecreasetherollingforceincreaseinducedbytheMRVRincrease,whichisimposingtensionatthesametimewhentheMRVRincreases,inordertoimproveeveneliminatethebulgedefect,andenhancethetubedimensionprecision.

简介：OnNovember3to5,theBeijingSummitoftheChina-AfricaCooperationwasheldinBeijing.ThePeople'sDaily,thecentralgovernment-administratednewspaper,praisedthisasaNewStartingPointforSino-AfricanRelations,markingthatthehalf-centurySino-Africanfriendshipthathassteppedintoanewhistoricalperiod.Duringtheforum,China'sForeignTradeinterviewedMr.MohamedA.ElMasry.ChairmanofFederationofEgyptianChamberofCommerce.'InEgypt,peoplefeelveryproudofChina,andaboutwhattheChinesepeoplehaveachieved,webelievethatasAfricans,wewanttostrengthentiesbetweenChinaandAfrica.That'swhyEgyptianPresidentHosnyMubarakwillcontinuetohavespecialvisitstoChinaafterthesummitonNovember6and7,inordertoenhancetraderelationsbetweenEgyptandChina,especiallyininvestment,tourism,etc.'Mr.Masrisaid.ByEditor