简介:ThesusceptibilityofweldedjointfortheX65pipelinesteeltoH2Sstresscorrosioncracking(SCC)isinvestigated.SCCtestsonthesteelarecarriedoutintheenvironmentbasedonNACETM-01-77solutionwithsaturatedgaseousH2S.Thethresholdstressintensityfactorandcrackpropagationvelocityarecalculatedaccordingtowedge-openingloading(WOL)specimens.Thethree-dimensionalelastic-plasticfiniteelementanalysisofWOLspecimensisperformedbyusingtheFEMprogrammingpackageANSYS.Stressfieldandconcentrationofhydrogendistributionpropertyaheadofthecracktipareobtained.ThispapersurveyedthemicrostructureofweldedjointandstudiedonthemechanicalpropertiesofX65pipelinesteel.Itprovidesexperimentalbasisforstudyingstresscorrosion.Theresultsofnumericalanalysisareconsistentwithconclusionsofstresscorrosiontest.
简介:Chinaisgloballyacknowledgedas'KingdomofBamboo',andZhejiangProvinceisnationallyrecognizedasthefirstprovinceofbambooinChina.SystematicandoverallanalysisismadebytheapproachofcasestudyonwhyZhejiangcangetsuchamarvelousachievementsoastoprovidesignificantreferencesandinstructionsforbamboodevelopmentforothercountrieswhodesiretolearntechnologiesandknow-howfromChina.Themaincontributionsareconcludedasbelow:1)Quickprogressofbambootechnologyprovidesastrongback-upforbambooindustrydevelopment;2)Governmentalsupportspromotethebalanceddevelopmentofbambooindustry,includingfavorablepolicy,financialsupport;3)Goodrelationofbamboocultivationandprocessing;4)Specialsoci-economicandhumanitarianadvantagesforbamboodevelopment,includinggoodexportenvironment,dynamicprivateeconomy,bambooindustryzone,excellenttalentsofbamboo;and5)Quickexpansionofinternationalanddomesticbamboomarketstimulatesanddrivesthedevelopmentofbambooindustry
简介:StaticCoulombstresschangeinducedbyearthquakeslipisfrequentlyusedtoexplainearthquakeactivitiesandaftershockdistribution.However,someparametersfortheCoulombstresscalculationareunabletobewellconstrainedfromlaboratoryexperimentsandfieldobservations.DifferentparametersmaydirectlyaffectthepatternofstaticCoulombstress.ThestaticCoulombstresschangesinducedbytheWenchuanearthquakecalculatedbysixresearchgroupsarenotconsistentwitheachother.Toinvestigatehowtheparametersaffectthecalculationresults,wechangetheparametersinturnthroughmodelingandcomparetheresultsofdifferentcalculationparameters.Wefindthatgravity,positionandstrikeofreceiverfaultshavelittleinfluenceoncoseismicCoulombstresscalculations,butotherparameterscanchangethevalueandsignoftheresultsinvariousdegreesespeciallyaroundtheearthquakeruptureplane.ThereforetheuncertaintyanalysisofstaticCoulombstresschangeinducedbyearthquakeshouldbetakenintoconsiderationintheearthquakehazardanalysis.
简介:Researchingthedynamicdistributioncharacteristicsandtrendevolutionofagriculturalcarbonemissionsisofconsiderablesignificanceinformulatinganeffectiveagriculturalcarbonreductionpolicy.Basedonmeasurementofagriculturalcarbonemissionsof31provincesovertheperiod2002-2011,thestudyobservedregionaldifferencesandthedynamicevolutionofdistributionofagriculturalcarbonemissionsusingagriculturalcarbonintensityastheindicator,accompaniedbyGinicoefficientsandthekerneldensityestimationmethod.TheresultsdemonstratefirstthatagriculturalcarbonemissionsforChinashowanobviousnonequilibriumnatureinregardtospatialdistribution.Accordingtothedifferencesinagriculturalcarbonemissionsdynamictrends,wedividedthe31regionsintofourtypes-continuousdecline,fluctuatingdecline,continuousincrease,andfluctuatingincrease.Further,agriculturalcarbonemissionsintensityshowedadownwardtrendwithsignificantdifferencesintheresearchareas.Second,thegapinspatialdistributionofnationalagriculturalcarbonemissionsisgraduallyexpandingbasedontheresultscalculatedbyGinicoefficient.Fromtheperceptionofregionaldifferencesinagriculturalcarbonemissions,theeasternregionshowedanaveragelevel,thegapwasmoreobviousinthecentralregion,whilewesternregionshowedatrendoffluctuatingdownward.Third,accordingtoestimationbykerneldensity,theregionaldisparityinagriculturalcarbonemissionshadadownward,butlimited,trend.Inregardtoagriculturalcarbonemissionsoverthethreeareas,theregionalgapnotonlytendedtodecreasebutalsoshoweda"fourway"differentiationphenomenonintheeasternregion.Thedifferenceinthecentralregiondifferencewasnarrower.Onthewhole,thegapforthewesternregionreducedsteadilyoverasmallrange.
简介:摘要:本文针对学生不易掌握导数含参数问题中参数该如何分类的问题,通过对几个典型问题的探究,结合流程图来对参数的分类方法和含参数问题的求解步骤来进行总结,形成解决此类问题的模式化解题方法。用流程图来体现参数的分类方法,直观明了,易理解,将解题思想流程化,易操作。