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20 个结果
  • 简介:Inordertopredictthemechanicalperformanceofthepolyvinylchloride(PVC)atahighoperatingtemperature,aseriesofshort-termtensilecreeptests(onetenthofthephysicalagingtime)ofthePVCarecarriedoutat63Cwithasmallconstantstressbyadynamicmechanicalanalyzer(DMA).TheStruik-Kohlrausch(SK)formulaandStruikshiftingmethodsareusedtodescribethesecreepdataforvariousphysicalagingtime.AnewphenomenologicalmodelbasedonthemultiplerelaxationmechanismsofanamorphouspolymerisdevelopedtoquantitativelycharacterizetheSKparameters(theinitialcreepcompliance,thecharacteristicretardationtime,andtheshapefactor)determinedbytheagingtime.ItisshownthatthemomentarycreepcompliancecurveofthePVCat63CcanbeverywellfittedbytheSKformulaforeachagingtime.However,theSKparametersforthecreepcurvesarenotconstantduringtheagingprocessattheelevatedtemperatures,andtheevolutionoftheseparametersandthecreeprateversusagingtimecurvesatthedoublelogarithmiccoordinateshaveshownanonlinearphenomenon.Moreover,thecreepmastercurvesobtainedbythesuperpositionwiththeStruikshiftingmethodsareunsatisfactoryinsuchacase.Finally,thepredictedresultscalculatedfromthepresentmodelincorporatingwiththeSKformulaareinexcellentagreementwiththecreepexperimentaldataforthePVCisothermallyagedatthetemperaturerelativelyclosetotheglasstransitiontemperature.

  • 标签: 玻璃化转变温度 蠕变性能 时效温度 对接 老化时间 C相
  • 简介:TheArrheniuslawimpliesthatreactionrateisacontinuousfunctionoftemperature.However,thesteadylaminarflameletmodel(SLFM)doesnotexplicitlygivethisfunctionalrelationship.ThepresentstudyaddressesthisrelationintheSLFM.Itisfoundthatreactionrateisnotcontinuousinthemixture-fractionspace.Asaresult,theSLFMisunabletopredictlocalextinctionandreignition.Furthermore,weusetheunstablebranchofthe"S-curve"tofillthegapbetweensteadyburningbranchandextinctio...

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  • 简介:Viscoelasticityandtemperaturecansignificantlyafecttheperformanceofadielectricelastomer.Inthecurrentstudy,weuseathermodynamicmodeltodescribetheefectoftemperatureandviscoelasticityontheelectromechanicalresponseundergoingacyclicelectricloadbytakingintoaccountofthetemperaturedependentdielectricconstant.Becauseofthesignificantviscoelasticityinthedielectricelastomer,thedeformationandthenominalelectricdisplacementcannotkeepinphasewiththeelectricfieldatlowfrequencies.Theresultsshowthatthemagnitudeofthecyclicelectromechanicalactuationstrainincreaseswiththedecreaseofthetemperatureanddecreaseswiththeincreasingfrequency,andviscoelasticitycanresultinsignificanthysteresisfordielectricelastomersunderarelativelowtemperatureandalowfrequency.

  • 标签: 反应温度 粘弹性 弹性体 介电 动态响应 热力学模型
  • 简介:Acousticfatiguelifeevaluationisessentialforthermalprotectionstructuresduetotheseverethermo-acousticloadinservice.AstudyontemperaturedependenceofacousticfatiguelifeforaC/SiCpanelispresentedinthispaper.EffectsoftemperatureonboththestructuralresponsesandtheS–Ncurvesareinvestigated.TheDirlikmethodisadoptedtopredictthefatiguelifeofaC/SiCpanelatthreedifferenttemperaturesrespectively.Significantdifferencesareobservedfromtheresultsofnumericalsimulationsbetweenthefatiguelivesofthepanelinthethreecases.Thetemperature-dependenceofacousticfatiguelifeofaC/SiCpanelisverified,andfatiguetestofthematerialneedstobemoreattentivelyperformed.

  • 标签: 温度依赖性 疲劳寿命 保护结构 SIC纤维 热防护结构 寿命评价
  • 简介:Thermalcontactresistanceplaysaveryimportantroleinheattransferefficiencyandthermomechanicalcouplingresponsebetweentwomaterials,andacommonmethodtoreducethethermalcontactresistanceistofillasoftinterfacematerialbetweenthesetwomaterials.AtestingsystemofhightemperaturethermalcontactresistancebasedonINSTRON8874isestablishedinthepresentpaper,whichcanachieve600Cattheinterface.Basedonthissystem,thethermalcontactresistancebetweensuperalloyGH600ma...

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  • 简介:在房间温度的第一次干燥的压路机颤动milling被用来准备活跃的碳(交流)nano粒子并且作为电极材料搽粉修改MnO2。在30min交流是到有增加的crystallinity和更高特定的表面区域的3050nm的一种吝啬的粒子尺寸的milled,主要mesoporous并且与改进毛孔直径分发。然后,交流nano粒子与MnO2被合并或做铋的MnO2nano粒子由solgel方法综合了为学习他们的电气化学的表演准备nano合成的电极材料。交流nano粒子与做铋的MnO2nano粒子被发现与增加电流与特定的电容拥有优秀电气化学的性质直到308F/g并且没有明显的变细的10wt.%结合了。我们的方法似乎打开一个新方法改进基于的电极材料为象超级电容器那样的干净精力使用了的交流。

  • 标签: 活性碳 滚筒振动 电极材料 室内空气
  • 简介:Bymeansofadoublemirrorinterferometryatwo-dimensionaltemperaturedistributionmeasurementinconvectivethermalboundarylayersispresented.Whenthecoldairflowsalongahotplatemodel,theinterferometricfringeinsidetheboundarylayerwillbend.Accordingtothedisplacementofthefringeandtherelationbetweentemperatureandindexofrefraction,atwo-dimensionaltemperatureprofileisobtained.Allisaccomplishedbyopticaldevicewiththehelpofmicro-computerwithoutanycontactwiththeflowfield.

  • 标签: BOUNDARY layer temperature distribution LASER INTERFEROMETRY
  • 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:Inarecentstudy,aregimechartwasestablishedforshearedgranularsystems.Forasoftparticlesystemundersimpleshear,theinternalstressshowedarangeofratedependency.Astheparticleconcentrationincreased,thesystemtransitionedfromakineticgastoaplasticsolid.Thistransitionwasgradualforlowstiffnesssystemsbutbecamemoreabruptasthestiffnessincreased.Inthisstudy,therelationshipbetweenthegranulartemperatureandpressureisinvestigatedforthesamesystemofparticles.Thegranulartemperatureisdefinedastheaveragekineticenergyperunitvolumeandthepressureisdefinedasthetraceofthestresstensor.Itisfoundthatthispressure-temperature(P-T)curvedepictsasharpturnwhenthesystemmovesawayfromthekineticgasregime.However,nosignatureisfoundintheP-Trelationshipinotherregimes.

  • 标签: 颗粒系统 温度关系 简单剪切 压力 政权 状态
  • 简介:有温度分发上的放射效果的三维的Couette流动的理论分析被分析了,当在更低的静止的板的液体的注射是一条横向的正弦曲线时一个;它由通过上面的多孔的板的经常的吸的相应移动在一致运动。由于这类注射速度,流动变得三维。Prandtl数字的效果,放射参数;热转移的率上的注射参数被图的帮助检验了。Prandtl数字比注射或放射参数在温度分发上有大得多的效果。

  • 标签: 三维库爱特流动 温度分布 不可压缩流 传热 辐射效应 注入
  • 简介:Afiniteelementisestablishedforanalyzingthedynamicalmechanicsanddeformationofsteelframeathightemperaturewhenitisrapidlycooleddownbyspraywaterinfirefighting.Thesimulationresultshowsthatremarkablemechanicalcouplingeffectsareproducedintheprocess,andthesectionalstressinrapidcoolingdownisfoundconsiderablylargerthanthatinheating-up.Meanwhile,thestressanddeformationofabeammainlyrelatedtocoolingrateandlocationaremuchlargerthanthoseofacolumninrapidcooling.Infirefighting,thestructureonthefirstorsecondfloorwasmoredangerousthanthoseonotherfloorsinrapidcooling.Theseresultscouldprovideatheoreticalreferenceforthedesignofsteelstructureandfirefighting.

  • 标签: 快速冷却 动态力学 钢框架 变形 喷水灭火 高温
  • 简介:三FCC催化剂的液体床稳定性上的温度的效果在液体床弹性上通过考虑被分析了。在最小的起泡的弹性模量上的温度的效果上的试验性的调查结果调节,(E)mb,被分析使用Foscolo和Gibilaro(1984)开发的水动力学液体床稳定性模型并且采用Mutsers和Rietema(1977)开发的interparticle-forces-based稳定性标准。为两个模型,与温度在(E)mb控制变化的参数被讨论,这些的能力当模特儿以便建立液体床弹性和分析的起源在使流体化的催化剂的稳定性上在水动力学和interparticle力量的相对重要性之间区别。

  • 标签: 分析方法 流化床 稳定性 催化剂
  • 简介:Inthispaper,theKirchhoffstransformationispopularizedtothenonlinearheatconductionproblemwhichtheheatconductivitycanbeexpressdasamultinomialoftemperaturefirstly,theboundaryconditionofheatconductionproblemisdeterminedbyanalytics.Secondly,theincubationperoidsuperpositionandthelinearcombinationlawisemployedtosimulatethetransientphassestransformationintheprocessofheattreatmentofmaterials.Thatthebegintimeofphasetransformation,thetypeofphasetransformationandtheamountofphaseconstitutionisdeterminedsimply.Finally,thethree-dimensionDualReciprocityBoundaryElementMethodisusedtoanalysisthetotalprocessofvariousheattreatmentofcomponent,theresultsofnumericalcalculationofexamplesshowthatthemethodprovidedinthispaperiseffectivce.

  • 标签: heat treatment phase TRANSFORMATION temperature FIELD
  • 简介:NanofluidswerepreparedbydispersingCunanoparticles(~20nm)inn-tetradecanebyatwo-stepmethod.Theeffectivethermalconductivitywasmeasuredforvariousnanoparticlevolumefractions(0.0001-0.02)andtemperatures(306.22-452.66K).TheexperimentaldatacompareswellwiththeJangandChoimodel.Thethermalconductivityenhancementwaslowerabove391.06Kthanforthatbetween306.22and360.77K.Theinterfacialthermalresistanceincreasedwithincreasingtemperature.Theeffectivethermalconductivityenhancementwasgreaterthanthatobtainedwithamoreviscousfluidasthebasemediaat452.66KbecauseofnanoconvectioninducedbynanoparticleBrownianmotionathightemperature.

  • 标签: 有效热导率 铜纳米粒子 纳米流体 高温度 颗粒体积分数 有效导热系数
  • 简介:Thispaperfocusesontheeffectoftemperatureontheout-of-planecompressivepropertiesandfailuremechanismofcarbonfiber/epoxycompositepyramidaltrusscoressandwichpanels(CF/CPTSP).CF/CPTSPwithnovelreinforcedframesaremanufacturedbythewaterjetcuttingandinterlockingassemblymethodinthispaper.Thetheoreticalanalysisispresentedtopredicttheout-of-planecompressivestiffnessandstrengthofCF/CPTSPatdifferentambienttemperatures.Thetestsofcompositesandwichpanelsareperformedthroughoutthetemperaturerangefrom-90℃to180℃.Goodagreementisfoundbetweentheoreticalpredictionsandexperimentalmeasurements.ExperimentalresultsindicatethatthelowtemperatureincreasesthecompressivestiffnessandstrengthofCF/CPTSP.However,thehightemperaturecausesthedegradationofthecompressivestiffnessandstrength.Meanwhile,theeffectsoftemperatureonthefailuremodeofcompositesandwichpanelsarealsoobserved.

  • 标签: 碳纤维复合材料 复合夹芯板 环境温度 压缩性能 碳纤维/环氧树脂复合材料 框架
  • 简介:这份报纸与可变的墙温度在一个垂直的可渗透的锥上讨论micropolarnanofluid的自然传送对流边界层流动。非类似的答案被获得。在管理流动的边界层近似下面的非线性地联合的微分方程用一个有效、反复的、tri斜的、含蓄的有限差别方法数字地被解决。为两nanofluid的不同试验性的关联有效粘性和nanofluid热电导率被考虑。作为旋涡粘性参数增加,两个都,速度介绍,这被发现并且本地Nusselt数字减少。在在这调查考虑的所有nanoparticles之中,另外,Cu给好传送对流。

  • 标签: micropolar nanofluid 非类似的答案 有限差别方法 不一致的加热 O361
  • 简介:THEANALYTICALSTUDYONTHELASERINDUCEDREVERSE-PLUGGINGEFFECTBYUSINGTHECLASSICALELASTICPLATETHEORY(Ⅰ)-TEMPERATUREFIELDSZhouYichun...

  • 标签: long PULSED laser. the RPE. TEMPERATURE