简介:Thebeamof35MeV/u~(40)ArwasdeliveredbyHIRFL(HeavyIonResearchFacilityatLanzhou).Atargetof674μg/cm~(2197)Auwasusedintheexperiment.Theexperimentwasmadeattheterminaloflargecylindeicalscatteringchamber,inwhichsixtelescopesareusedtomeasurechargedparticlesemittedintherearandmiddle
简介:Finiteelementmethod(FEM)hasbeenusedtoanalyzethestressandstrainfieldsandthestresstri-axiallevelsaroundthetipofthecrackundermode-Ⅱloading.Theresultsshowthat:undermode-Ⅱloading,thedirectionofthemaximumtensilestressandthatofthemaximumtri-axiallevels(R_)existatanangleof-75.3°fromtheoriginalcrackplane:themaximumshearstressandR_=0existalongtheoriginalcrackplane.Mode-ⅡloadingexperimentusingBHW-35steelatdifferenttemperaturesshowthattherearetwokindsoffracturemode.openingmode(ortensilemode)andslidingmode(orshearmode).Ade-creaseintemperaturecausesthefracturemodetochangefromshearmodetotensilemode.ForBHW-35steel,thiscriticaltemperatureisabout-90C.Actually.underanykindofloadingmode(modeⅠ,modeⅡ,modeⅢormixedmode),therealwaysexistseveralkindsofpotenitalfracturemodes(forexample,openingmode.slidingmode.tearingmodeormixedmode).Theeffectoftemperatureundermode-Ⅱloadingisactuallyrelatedtothechangeoftheelastic-plasticpropertiesofthematerial.
简介:Astudywasmadeofmagneticfieldeffects(MFEs)onthephotoreductionreactionof2-methyl-1,4-naphthoquinone(MNQ)inBrij35micellarsolutioncontaining4-1auroylamino-TEMPO(2,2,6,6-tetramethylpiperidine-1-oxyl)radical(L-R·)undermagneticfieldsbelow1.75Tbyananosecondlaserflashphotolysistechnique.ThetripletMNQmainlyunderwentthehydrogenabstractionfromBrij35moleculetogivearadicalpair.Theescapedradicalyieldincreasedwithmagneticfieldsfrom0to0.62Tandthensaturatedfrom0.62to1.75T.MFEsforbothsystemscanbeexplainedbytherelaxationmechanism.However,itwassupposedthatadditionalradical,L-R.affectedtheMFEsmainlythroughenhancingthespin-spininteractionsofradicalpairs.TheeffectofthemicellesizeonMFEsofthestudyingsystemwasalsodiscussed.