学科分类
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22 个结果
  • 简介:在这个工作,试验性的调查被追求了分析影响向下在在在冲积隧道的圆形的桥码头附近的旋涡结构的流动和相应变化的狂暴的特征上的渗出物。实验为没有渗出物,10%渗出物和20%渗出物盒子与不同尺寸的圆形的墩在沙床隧道被进行。象速度和雷纳兹压力那样的狂暴的流动统计的测量被发现在scour洞在以内否定墩在上游而申请向下,渗出物延迟在速度和雷纳兹引起减少的流动的颠倒强调。更高级的雷纳兹砍因为生产,应力在下游的方面占优势弄醒旋涡。到彻底的雷纳兹的所有爆炸事件的贡献砍压力生产被观察了增加与向下渗出物。不可分的规模的分析建议旋涡的那种尺寸与渗出物增加,它为粒子活动性的增加负责。开始搜索评价是消退逐渐地象与一样与膨胀预定的更多增加了向下渗出物。存在向下,渗出物向墩的下游的方面减少旋涡和移动的深度和长度。

  • 标签: 湍流特性 河床形态 桥墩 雷诺兹应力 下渗 剪切应力
  • 简介:Soilsalinityisoneofthemostimportantproblemsofcropproductioninestuarineandcoastalzones.Improvementinsalttoleranceofmajorfoodcropsisanimportantwayfortheeconomicutilizationofcoastalzones.Thisstudyprovedthattheapplicationofsalicylicacid(SA)improvedthegrowthandyieldundersaltstressconditionsandinvestigateditsphysiologicalmechanismsforsalttolerance.TheinvestigationontheeffectofSAforsalttoleranceduringgerminationshowedthatthedecreasedratesofgerminationandgrowth(intermsofshootandrootlengths)bythesaltstressweresignificantlyincreasedbytheSAapplication(SA+NaCl).ThetreatmentofSAtothehighandlowsalinesoilsenhancedthegrowth,yieldandnutrientvaluesofrice.TheeffectsofSAonNa+,K+andCl–ionicaccumulationweretracedundersaltstressconditionbyinductivelycoupledplasmaopticalemissionspectrometryandionchromatography.ItwasrevealedthattheincreasedaccumulationofNa+andClˉionsbythesaltstresswerereducedbySAapplication.AnincreasedconcentrationofendogenousSAlevelwasdetectedfromtheSA-treatedricevarieties(ASD16andBR26)byliquidchromatographyelectrosprayIonization-tandemmassspectrometry.Theactivitiesofantioxidantenzymessuchassuperoxidedismutase,catalaseandperoxidasewereincreasedbysaltstresswhereasdecreasedbytheSAapplication.ThestudyprovedthattheapplicationofSAcouldalleviatetheadverseeffectsofsaltstressbytheregulationofphysiologicalmechanisminriceplants.Inspiteofsaltstress,itcanbeappliedtothecoastalandestuarineregionstoincreasethericeproduction.

  • 标签: salicylic acid SALT tolerance ORYZA SATIVA
  • 简介:Hydrocarbonmicro-seepagecancauseoxidationreductionreactionsandproducealteredmineralsinsurfacesedimentsandsoil.Thetypicalalteredmineralsmappingbytheirdiagnosticspectralfeaturesonhyper-spectralimagesisanimportanttoolforthepetroleumexplorationindustry.Inthisstudy,theairbornehyper-spectraldatawereusedtoinvestigatethealteredmineralsinducedbyhydrocarbonmicro-seepagesbyspectralfeaturefitting(SFF)intheloesscoverageareaofXifengOilfield.Theresultsrevealthatthedistributionregionofthealteredmineralsinducedbyhydrocarbonmicro-seepageislargerthantheknownoilfieldexplorationarea.Thepotentialhydrocarbonmicro-seepageregionwasalsorevealedbythedistributionofalteredmineralsbesidestheknownhydrocarbonarea.Afastindexwasproposedbytheabsorptiondepthsofclayandcarbonatemineralsforassessmentofhydrocarbonmicroseepage.Anditgavemuchclearerboundariesforthehydrocarbonmicro-seepageintheloesscoverageareathanthosebythealteredmineralmapping.Inaddition,somefieldsampleswereanalyzedbyX-raydiffraction(XRD)andatomicabsorptionspectrophotometertovalidatetheresults.Withintheextentsofhydrocarbonmicro-seepage,therearelowercontentsofferricironandhighercontentsofcarbonatemineralsinthesesamples.Therefore,itissatisfactorytohavetheairbornehyper-spectraldatatooutlinetheextentsofhydrocarbonmicro-seepageforfurtherhydrocarbonexplorationintheloesscoveragearea.

  • 标签: 烃类微渗漏 蚀变矿物 高光谱数据 西峰油田 渗漏检测 原子吸收分光光度法
  • 简介:Droughtisthemajorabioticstressfactorthatlimitsriceproductionworldwide.Toevaluatetheosmoticstressresponsesinricevarietiesunderdroughtcondition,atotalof42high-yieldingricevarietieswerecollectedfromvariousresearchstationsofKeralaAgriculturalUniversityinIndia.Theexperimentalsetupcomprisesofinitialhydroponictreatmentsatdifferentosmoticpotentials,artificiallyinducedbydesiredstrengthsofpolyethyleneglycol(PEG6000),andfollowedbythepotplantedexperimentsintherain-out-zone.Theactivitiesofantioxidantenzymes,relativewatercontent,cellmembranestability,photosyntheticpigments,prolinecontent,alongwithplantgrowthparametersofthevarietiesunderdroughtconditionwereevaluated.Moreover,thestandardscoresofthesericevarietieswereassessedunderstressandrecoveryconditionsbasedonthescoringscaleoftheStandardEvaluationSystemforrice.Amongthe42ricevarieties,weidentified2ricevarieties,SwarnaprabhaandKattamodan,withlessleafrolling,betterdroughtrecoveryabilityaswellasrelativewatercontent,increasedmembranestabilityindex,osmolyteaccumulation,andantioxidantenzymeactivitiespointedtowardstheirdegreeoftolerancetodroughtstress.Thepositiveadaptiveresponsesofthesericevarietiestowardsdroughtstresscanbeusedinthegeneticimprovementofricedroughtresistancebreedingprogram.

  • 标签: DROUGHT resistance RICE ANTIOXIDANT ENZYME OSMOLYTE
  • 简介:Thestress-inducedmagneticdomainswitchinginFeGathinfilmsisstudiedusingphase-fieldmethod.Inparticular,themagneticfieldisappliedalongthe[110]directionandbiaxialstressesareappliedalong[100]and[010].Acompressivepre-stresscorrespondstoasmallercoercivemagneticfieldwhileatensilepre-stresscorrespondedtoalargercoercivefield.Atthesametime,itisalsofoundthatthetransitionbetweenbutterflyandsquare-likemagnetostrictionloopsoccursatthecriticaloppositebiaxialstressstate.Thetwodifferentevolutionscorrespondtotwodifferentmechanisms:oneisthatthesingledomainswingsacrossafanareabackandforth;theotheristhatthesingledomainturnsaclockwisecircle.Theresultscanbeexplainedbythestresstunedanisotropyenergywell.

  • 标签: 磁致伸缩 应力诱导 正方形 蝴蝶 相场方法 双轴应力
  • 简介:有在紧张和压缩的不同moduli的材料被称为双性人模量材料。Graphene是有最高的力量和最薄的厚度的如此的一种材料。在这份报纸,受到温度效果并且放了在Winkler地基上的双性人模量横梁的机械反应被学习。关于中立的轴位置和双性人模量基础横梁的正常紧张的未经决定的参数的微分方程被建立。然后,地基横梁的正常压力,弯曲时刻,和排水量的分析表情被导出。同时,一个计算过程基于有限元素方法(女性)被开发获得双性人模量结构的温度压力。获得的双性人模量解决方案能恢复古典模量解决方案,这被显示出,并且结果由分析表达式,现在的女性的过程,和传统的女性的软件获得是一致的,它验证现在的分析模型和过程的精确性和可靠性。最后,双性人模量结果之间的差别和古典一样的模量结果被讨论,并且为在实际工程计算并且优化某些双性人模量成员的几个合理建议被介绍。

  • 标签: 双性人模量横梁 Winkler 基础 温度应力 分析答案 节目的第二等的开发 O343.5
  • 简介:为有一个横向的裂缝的一条半长带的飞机橡皮问题被调查。起始的问题被一个不可分的转变方法的使用与一个概括计划归结为一个一个维的连续问题。一个维的问题首先作为一个向量边界问题被提出,然后归结为三个单个不可分的方程(SIE)的一个系统。系统被一个直角的多项式方法和一个特殊概括方法的使用解决。这个工作的贡献是核的考虑在解决系统的固定奇特。相对半长带的裂缝长度和它的地点侧面的方面被调查简化问题陈述。这简化把起始的问题归结为二SIE的一个系统。

  • 标签: 半长带 横向的快克 草地工作 不可分的转变 固定奇特 单个不可分的方程(SIE )
  • 简介:Ascientifichypothesisisproposedandpreliminarilyverifiedinthispaper:underthedrivingofseepageflows,theremightbeaverticalmigrationoffine-grainedsoilparticlesfrominteriortosurfaceofseabed,whichisdefinedas‘sub-bottomsedimentpumpaction’inthispaper.FieldexperimentswereperformedtwiceontheintertidalflatoftheYellowRiverdeltatostudythisprocessviabothtrappingthepumpedmaterialsandrecordingtheporepressuresinthesubstrate.Experimentalresultsarequiteinterestingaswedidobserveyellowslurrywhichismainlycomposedoffine-grainedsoilparticlesappearingontheseabedsurface;seepagegradientswerealsodetectedintheintertidalflat,undertheactionoftidesandsmallwindwaves.Preliminaryconclusionsarethat‘sedimentpump’occurswhenseepageforceexceedsacertainthreshold:firstly,itisbigenoughtodisconnectthesoilparticlesfromthesoilskeleton;secondly,thedegreeofseabedfluidizationorbioturbationisbigenoughtoprovidepreferredpathsforthedetachedmaterialstomigrateupwards.Thentheywouldbefirstlypumpedfrominteriortothesurfaceofseabedandtheneasilyre-suspendedintooverlyingwatercolumn.Influentialfactorsof‘sedimentpump’aredeterminedashydrodynamics(waveenergy),degreeofconsolidation,indexofbioturbation(permeability)andcontentoffine-grainedmaterials(sedimentaryage).Thisnewperspectiveof‘sedimentpump’mayprovidesomeimplicationsforthemechanisminterpretationofseveraluncleargeologicalphenomenaintheYellowRiverdeltaarea.

  • 标签: sediment PUMP action vertical migration FINE-GRAINED
  • 简介:Thestressintensityfactor(SIF)isacriticalparameterassociatedwiththefracturebehaviourofmaterials.Inthispaper,weselectthedisplacementfunctionaroundacracktipastheshapefunctionofthedigitalimagecorrelation(DIC),whichmakesitpossibletodirectlycalculatetheSIFbythecorrelationscheme.Moreover,weuseanon-rectangularsubset,whichcanreducetheinfluenceofplasticdeformationandcrackwidthontheDICmeasurementaccuracy.WemeasuredtheSIFofamodeIcrackinasuper-hardaluminiumalloyspecimentoverifytheperformanceoftheproposedmethod.OurexperimentalresultsshowthataDICwithaspecificshapefunctioncanbeusedtoaccuratelyandefficientlycalculatetheSIF.Furthermore,wealsopresentapracticalapplicationofourproposedmethodfordeterminingtheSIF,crackpropagationangleandcracktipdisplacement.

  • 标签: Digital image CORRELATION (DIC) SHAPE function
  • 简介:BasedonthedigitalwaveformdatarecordedbyXinjiangDigitalSeismicNetworkfortheXinyuan-HejingM_L6.8earthquakesequencesofJune30,2012,thispaperanalyzesthestressdropsofearthquakesequencesandthecorrelationcoefficientsoffocalmechanismssignificantforstrongaftershocks.Firstly,thesourceparametersoftheXinyuan-HejingM_L6.8earthquakesequencesareobtainedbyapplyingthespectrumanalysisandtheBrunessourcemodel.Then,thecorrelationcoefficientsofspectralamplitudesarecalculatedusingthelow-frequencyspectralamplituderecordedbythesamestationforthedifferentevents.Finally,basedontheresultsofthecorrelationcoefficientsofspectralamplitudes,theeventswithsimilarfocalmechanismsaregroupedusingtheclusteringmethod.Theresultsshowthat:(1)Thestressdropvaluesshowasteadytrendintheaftershocksequencecalmperiodandthestressdropvaluesshowarise-fallinstrongaftershocks.(2)Themovingaveragecorrelationcoefficientofamplitudespectrumbeginstospreadafterthemainshock.Itshowsthatthecorrelationdecreasesbetweenthemainshockandtheaftershocksinmechanisms.(3)Theresultsoffocalmechanismgroupsshowthattheearthquakesequencesaremainlystrikeslips.ThestressdistributionofthemainpressureaxisisnearlyNS,whichisthesameasthestructuralstressfield.(4)Themagnitudeandmechanismshowthatthereisanagreementbeforethestrongaftershock,whichshowsthattheregionalstressfieldisenhanced.

  • 标签: 震源机制 地震序列 应力降 相关系数 区域应力场 数字地震台网
  • 简介:ThenonlinearvibrationsofviscoelasticEuler–BernoullinanobeamsarestudiedusingthefractionalcalculusandtheGurtin–Murdochtheory.EmployingHamilton'sprinciple,thegoverningequationconsideringsurfaceeffectsisderived.Thefractionalintegro-partialdifferentialgoverningequationisfirstconvertedintoafractional–ordinarydifferentialequationinthetimedomainusingtheGalerkinscheme.Thereafter,thesetofnonlinearfractionaltime-dependentequationsexpressedinastate-spaceformissolvedusingthepredictor–correctormethod.Finally,theeffectsofinitialdisplacement,fractionalderivativeorder,viscoelasticitycoefficient,surfaceparametersandthickness-to-lengthratioonthenonlineartimeresponseofsimply-supportedandclamped-freesiliconviscoelasticnanobeamsareinvestigated.

  • 标签: 分数阶微积分 非线性振动 粘弹性系数 表面效应 伯努利 振动分析
  • 简介:Themajorityofrice(OryzasativaL.)producedinthesouthernUSAisdrill-seededandgrownunderupland-likeconditionsbecausepermanentfloodingisestablishedafterthefour-leafstage.Therefore,riceduringtheseedlinggrowthstagewillbesubjectedtovariablesoilmoisturecontent.Agreenhouseexperimentwasconductedtoevaluatetheperformanceof15ricecultivarscommonlygrowninMississippiofUSAunderearly-seasonsoilmoisturestress.Twentymorpho-physiologicalparametersofriceseedlingssubjectedtothreedifferentlevels(100%,66%and33%fieldcapacity)ofsoilmoisture,from10to30daftersowing,weremeasured.Significantmoisturestress×treatmentinteraction(P<0.001)wasobservedformostoftheparameters.Further,thetotaldroughtresponseindex(TDRI)wasdevelopedtoscorethecultivarsfordroughttolerancewiththevariationfrom26.88to36.21.Accordingly,thecultivarswereclassifiedintodifferentgroupsoftolerance.ThecultivarsCL152andCL142-ARwereclassifiedastheleastandthemosttoleranttodroughtbasedonTDRIandstandarddeviation,respectively.Eventhoughbothtotalroot(R2=0.98)orshoot(R2=0.76)droughtresponsesindiceswerepositivelycorrelatedwithTDRI,roottraitswereimportantinderivingtheindices.Therefore,TDRIcouldbeusedtoselectcultivarsfordroughttoleranceinagivenenvironmentanddevelopricevarietieswithearly-seasondroughttolerance.However,furtherresearchisneededtoidentifyandcharacterizetoleranceatotherstagestoassistbreedingprogramsinrice.

  • 标签: DROUGHT field capacity morpho-physiological parameter Oryza
  • 简介:Inflammationafterstrokeisthemaincauseofcerebralischemia/reperfusioninjury.Cascadingeventsafterinjurycanleadtocelldeath.Heatshockprotein70andotherendogenousinjury-signalingmoleculesarereleasedbydamagedcells,whichcanleadtosystemicstressreactions.Protectingthebrainthroughrepairbeginswiththestress-injury-repairsignalingchain.Thisstudyaimedtoverifywhetheracupunctureactsthroughthischaintofacilitateeffectivetreatmentofischemicstroke.Ratmodelsofcerebralischemia/reperfusioninjurywereestablishedbyZeaLonga'smethod,andinjurysiteswereidentifiedbyassessingneurologicalfunction,2,3,5-triphenyltetrazoliumchloridestaining,andhematoxylin-eosinstaining.ElectroacupunctureatacupointsBaihui(DU20)andZusanli(ST36)wasperformedinthemodelratswithdilatationalwaves,deliveredfor20minutesadayat2–100Hzandanamplitudeof2mA.Weanalyzedthebloodserumfromtheratsandfoundthatinflammatorycytokinesaffectedthelevelsofadrenotrophinandheatshockprotein70,eachofwhichfollowedasimilarbimodalcurve.Specifically,electroacupunctureloweredthepeaklevelsofadrenocorticotrophichormoneandheatshockprotein70.Thus,electroacupuncturewasabletoinhibitexcessivestress,reduceinflammation,andpromotetherepairofneurons,whichfacilitatedhealingofischemicstroke.

  • 标签: 缺血再灌注损伤 损伤修复 应激反应 脑卒中 电针 调节作用
  • 简介:ActivinA,amemberofthetransforminggrowthfactor-betasuperfamily,playsaneuroprotectiveroleinmultipleneurologicaldiseases.Endoplasmicreticulum(ER)stress-mediatedapoptoticandautophagiccelldeathisimplicatedinawiderangeofdiseases,includingcerebralischemiaandneurodegenerativediseases.ThapsigarginwasusedtoinducePC12celldeath,andActivinAwasusedforintervention.OurresultsshowedthatActivinAsignificantlyinhibitedmorphologicalchangesinthapsigargin-inducedapoptoticcells,andtheexpressionofapoptosis-associatedproteins[cleaved-caspase-12,C/EBPhomologousprotein(CHOP)andcleaved-caspase-3]andbiomarkersofautophagy(Beclin-1andlightchain3),anddownregulatedtheexpressionofthapsigargin-inducedERstress-associatedproteins[inositolrequiringenzyme-1(IRE1),tumornecrosisfactorreceptor-associatedfactor2(TRAF2),apoptosissignal-regulatingkinase1(ASK1),c-JunN-terminalkinase(JNK)andp38].Theinhibitionofthapsigargin-inducedcelldeathwasconcentration-dependent.ThesefindingssuggestthatadministrationofActivinAprotectsPC12cellsagainstERstress-mediatedapoptoticandautophagiccelldeathbyinhibitingtheactivationoftheIRE1-TRAF2-ASK1-JNK/p38cascade.

  • 标签:
  • 简介:被动导致电影的压力和危险性在在各种各样的pH价值的3.5%钠氯化物答案的7050铝合金的SCC被慢紧张率测试调查(SSRT)并且流动应力微分方法。结果证明到SCC的被动导致电影的压力和危险性与增加pH减少了价值什么时候pH7,当他们与增加pH增加了时价值什么时候pH>7。然而,当,腐蚀类型被解释脱落腐蚀什么时候pH=1并且14,并且没有电影,在标本的表面上形成。整个变化与pH导致电影的应力和SCC危险性阴谋当,价值两个都被介绍山谷形状。导致电影的压力的标志和数量与被动电影的作文有关,它用X光检查光电子被分析光谱学(XPS)。

  • 标签: 7050 铝合金 危险性到 SCC pH 价值 被动导致电影的应力
  • 简介:Purpose:Thepurposeofthisstudywastoinvestigatetheeffectsofobesityandhigh-intensityacuteexerciseonoxidant-antioxidantstatus,neurotrophicfactorexpression,andblood-brainbarrier(BBB)disruption.Methods:Twenty-fourhealthy,untrainedmen(12non-obese(mean14.9%bodyfat)and12obesesubjects(mean29.8%bodyfat))performed20minofcontinuoussubmaximalaerobicexerciseat85%maximaloxygenconsumption.Bloodsamplingwasperformedtoexaminetheoxidant-antioxidantstatus(reactiveoxygenspecies(ROS)andsuperoxidedismutase(SOD)),neurotrophicfactors(brain-derivedneurotrophicfactor(BDNF)andnervegrowthfactor(NGF)),andBBBdisruption(S100βandneuron-specificenolase)beforeandafteracuteexercise.Results:Theobesegroupshowedsignificantlyhigherpre-exerciseserumROSlevelsandsignificantlylowerpre-exerciseserumSODlevelsthanthenon-obesegroup(p<0.05).SerumROS,SOD,BDNF,NGF,andS100βlevelsweresignificantlyincreasedpost-exercisecomparedwithpre-exerciselevelsinboththenon-obeseandtheobesegroups(p<0.05).TheobesegroupshowedsignificantlyhigherserumROS,BDNF,NGF,andS100βlevelspost-exercisecomparedtothenon-obesegroup(p<0.05).Conclusion:OurstudysuggeststhatepisodicvigorousexercisecanincreaseoxidativestressandbloodneurotrophicfactorlevelsandinducedisruptionoftheBBB.Moreover,highlevelsofneurotrophicfactorinthebloodafterexerciseintheobesegroupmaybeduetoBBBdisruption,anditisassumedthatoxidativestresswasthemaincauseofthisBBBdisruption.

  • 标签: 水平运动 血脑屏障 氧化应激 高强度 脑源性神经营养因子 肥胖