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简介:LarixolgensisA.Henry(Changbailarch)isaproductivecommercialspeciesandgoodcandidateforafforestationinnortheastChina.Itiswidelyplantedinlead-stressedsoilswhichcaninduceoxidativedamageinthisplant.Increasingtolerancetolead(Pb)stressisthereforeofkeeninterest.Agreenhouseexperimentwasconductedtoidentifythebiomass,physiologicalresponsesandPbaccumulationofL.olgensisseedlingstoPbstressundersuccinicacid(SA)applicationandtoexploretheinteractionofexogenousSAapplicationsandstressresistance.L.olgensisseedlingswereplantedinPb-stressedorunstressedhapliccambisolsinpots.InPb-contaminatedsoilstheseedlingsweretreateddailywithconcentrationsofSAsolutionsatarateapproximatelyequivalentto0,0.04,0.2,1.0,or2.0mmolkg-1ofsoilfor10,20,and30days,respectively.Pbtreatmentinduceddamageintheseedlingsandledtotheinhibitionofbiomassaccumulationinroots,stemsandleaves,andariseinPbaccumulationinfinerootsandleaves.Malondialdehyde(MDA)contentandelectrolyteleakageinleavessignificantlyincreasedwhileperoxidase(POD)activities,solubleproteinandphotosyntheticpigmentcontentsinleaveswereallreduced.PhysiologicaltoxicitywaspromotedwithincreasingPbtreatmenttimes.WhenPb-stressedseedlingswereexposedtoSA(especially10.0mmolL-1over20days),thephysiologicalresponsesforPb-onlywerereversedandthebiomassofroots,stems,andleavesdramaticallyincreased.SAfacilitatedPbuptakeinfinerootsandleavesbutmorePbaccumulatedinfineroots.TheresultsdemonstratethatexogenousSAalleviatesPb-inducedoxidativeinjuriesandimprovesthetoleranceofL.olgensisseedlingstoPbstress.
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简介:由考虑界面的损坏并且用变化原则的效果,有界面的损坏的把压成薄片的盘子的三维的非线性的动态管理方程向精确压力分析基于一般six-degrees-of-freedom塔板理论被导出。为有界面的损坏的一个简单地支持的把压成薄片的盘子的interlaminar应力和非线性的动态反应的答案被使用有限差别方法获得,并且结果被比较与非线性的有限元素方法的答案验证。在数字计算,在接口和把压成薄片的盘子的非线性的动态反应的压力上的界面的损坏的效果被讨论。
简介:Vibrationfatigueisthemainfailuremodeofcompressorblade.Evaluatingthevibrationstressofbladethatleadstocrackingisveryusefulforanalysisofvibrationfatigue.Inthispaper,fatiguestressestimationmethodsbyquantitativefractographywerestudiedthroughexperimentalbladeandin-servicefirst-stagecompressorbladeinordertoevaluatetheinitiationvibrationstressofin-serviceblade.Theanalysisprocessofinitiationvibrationstresswasestablished.Theevaluatingresultofvibrationstressofin-servicebladesubjectedtocentrifugalforceandbendingvibrationstressagreeswithaeroenginetestresult.Itisshownthattheevaluationmethodcannotonlyevaluatetheequivalentfatiguestressesofdifferentcrackdepthsbutalsoyieldtheinitiationequivalentfatiguestress.
简介:我们在单轴的弯曲负担下面在T形榫眼和松开的雄榫(M<)家具关节在应力和紧张分布上学习了松开的雄榫尺寸的效果,并且决定了松开的雄榫长度的效果(30,45,60,并且90公里)并且把M<关节的时刻能力弄弯上的松开的雄榫厚度(6和8公里)与聚乙烯化合物的醋酸盐(PVAc)构造了粘合剂。在联合元素的压力和紧张分布然后为每个联合使用ANSYS有限元素(FE)被估计软件。关节的弯曲时刻能力与雄榫的厚度和长度显著地增加了。基于FE分析结果,在单轴的弯曲下面,最高砍压力价值在雄榫的中间的部分被获得,当时最高砍有弹性的紧张价值在在雄榫表面和榫眼的墙之间的胶水线被估计。砍强调在联合元素的有弹性的紧张价值通常与雄榫尺寸和相应弯曲时刻能力增加了并且砍。在预言的最大值之间有一致性砍关节的压力价值和失败模式。
简介:Currentproceduresformass-flowhopperdesignarebasedontheradialstresstheorydevelopedbyJenikeandinvolvethedeterminationofthecriticaloutletdimensionsforflowtobeinitiated.Theseproceduresignorethesurchargeloadsonthehopperandinvolveastudyofthepassiveorarchedstressfieldthatexistsunderflowconditions.Analternativeapproachasappliedtohopperwallloadanalysisistoemploythehorizontalslicemethod.Thearchedstressfieldandhorizontalslicemethodsofanalysisarecompared.Theinfluenceofsurchargeloadsinthedeterminationofhoppergeometryisinvestigated.
简介:Formulationintermsofhypersingularintegralequationsfortheinteractionbetweenstraightandcurvedcracksinplaneelasticityisobtainedusingthecomplexvariablefunctionsmethod.Thecurvedlengthcoordinatemethodandasuitablenumericalschemeareusedtosolvesuchintegralsnumericallyfortheunknownfunction,whicharelaterusedtofindthestressintensityfactor,SIF.
简介:Theformationandevolutionofdeformationtextureinpolycrystallinematerialsarestudiedbyphase-fielddynamicmodel.Inaddition,thedrivingforceoftextureevolutionisalsodiscussed.Inthismodel,grainswithdifferentorientationaredefinedbyasetofcontinuousnon-conservedorderparameterfields.Simulationresultsshowthatgrainswithpreferredorientationgrowattheexpenseofthosewithunfavorableorientations.Itismoreimportantthat,elasticpotentialratherthanelasticenergyplaysacrucialroleintheevolutionoftexturewhetherthepolycrystallinesystemissubjectedtouniaxialstressorshearstress.
简介:MagneticBarkhausennoise(MBN)isaphenomenonofelectromagneticenergyduetothemovementofmagneticdomainwallsinsideferromagneticmaterialswhentheyarelocallymagnetizedbyanalternatingmagneticfields.AccordingtoFaraday’slawofelectromagneticinduction,thenoisecanbereceivedbythecoilattachedtothesurfaceofthematerialbeingmagnetizedandthenoisecarriesthemessageofthecharacteristicsofthematerialsuchasstresses,hardness,phasecontent,etc.Basedonthecharacteristicofthenoise,researchingabouttherelationshipbetweentheresidualstressintheweldingassemblyandthenoisearecarriedout.Furthermore,dataprocessisperformedbyRMS(RootMeanSquare)equationandPowerSpectrumanalysis.
简介:目的methotrexate(MTX)的最重要的副作用是mucositis。这研究的目的是在收到methotrexate的老鼠在肠的损坏和氧化应力上评估沉金摘录的效果。方法实验在划分成六个组的男Wistar白化体老鼠上被执行。首先组织收到的正常盐口头上地,第二个组收到了沉金摘录(100mg瑡潩?????????????????假吗??
简介:BytheaftershockfrequencyestimationmethodbasedonthecalculationofcoseismicstaticCoulombstresschangesandrate-andstate-dependentfaultconstitutivelaw,wecalculatethefrequencyof"direct"aftershocksoftheWenchuanearthquakerelatedtocoseismicstaticCoulombstresschangesinitsaftershockzoneandtheareasnearby.Itshowsthatthefrequencyissignificantlylowerthanthetruthinthemainrupturezone,especiallyinthesouthernrupturezone,duetothedecreaseofstresslevelontheruptureplaneofthemainshockresultingfromcoseismicCoulombstresschange.ThestudyalsoshowsthattheeffectoftheCoulombstresschangeonthedurationofaftershockactivityisassociatedwiththelowerlimitmagnitude.Thedurationisabout15-16monthsforaftershocksaboveML4.0,andcloseto60monthsforaftershocksaboveML3.5.Inthisperiod,theratioofthe"direct"aftershockscausedbycoseismicCoulombstresschangerangesbetween44.7%to48.6%,whichsuggeststhat,eveninthe"effective"periodofcoseismicCoulombstresschanges,abouthalfoftheaftershocksonthemainshockruptureplaneareindependentofcoseismicCoulombstresschanges.Itispointedoutthatthoseaftershocksmayberelatedtotheaftersliportheviscoelasticrelaxation,whicharetimedependentcases.
简介:Inthepaper,sourcemechanismsof33small-moderateearthquakesoccurredinYunnanaredeterminedbymodelingofregionalwaveformsfromYunnandigitalseismicnetwork.TheresultshowsthatmostearthquakesoccurredwithinorneartheChuandianrhombicblockhavestrike-slipmechanism.TheorientationsofmaximumcompressivestressesobtainedfromsourcemechanismarechangedfromNNW-SSNtoNSintheareasfromnorthtosouthoftheblock,andtensilestressesaremainlyinENE-WSWorNE-SE.IntheeasternTibetanPlateau,theorientationsofmaximumcompressivestressradiatetowardoutsidefromtheplateau,andthetensilestressorientationsmostlyparalleltoarcstructures.Near28°Ntheorientationsofbothmaximumcompressivestressandtensilestresschangedgreatly,andtheboundaryseemstocorrespondtothesouthwesternextendedlineofLongmenshanfault.OutsideoftheChuandianrhombicblock,theorientationsofPandTaxesaresomedifferentfromthosewithintheblock.Thecomparisonshowsthatthesourcemechanismofsmall-moderateeventspresentedinthepaperisconsistencewiththatofmoderate-strongearthquakesdeterminedbyHarvardUniversity,whichmeansthesourcemechanismofsmall-moderateeventscanbeusedtostudythetectonicstressfieldinthisregion.