简介:Time-temperaturesuperpositionprinciple(TTSP)wasusedtoexaminedynamicviscoelasticpropertiesofChineseFir(Cunninghamialanceolata)woodatanextremelylowmoisturecontent(0.6%).Storagemodulusandlossfactordatawereobtainedatdifferentconstanttemperaturesrangingfrom25℃to150℃infrequencymultiplexingexperiments(0.1-20Hz).Allviscoelasticcurvesatothertemperatureswereshiftedalongthelog-frequencyaxistosuperimposethemonareferencetemperature(i.e.135℃inthisstudy)curve.Theextendedstoragemodulusandlossfactorisothermalmastercurveswereoverawiderangeoffrequency.TheshiftfactorsweredeterminedtobeafunctionoftemperatureandfittedintotheArrheniusequationwiththeleastsquaresmethod.TheresultsshowedthatthestoragemodulusdatawereexcellentlyfittedintotheArrheniusmodel,indicatingthevalidityofthemodeltocharacterizethedynamicstiffnessbehaviorofdrywoodintherangeof25-150℃usingtheTTSP.However,thetime-temperatureequivalencewasnotabletopredictthedampingproperties.
简介:Spinodalphaseseparationbehaviorofpoly(methylmethacrylate)/poly(styrene-co-acrylonitrile)(PMMA/SAN)blendswasinvestigatedbythetime-resolvedsmallanglelightscattering(SALS)technique.Itwasfoundthattheinfluenceoftemperatureonthescatteringintensityevolutionfollowedthetime-temperaturesuperpositionprinciple.TherelationshipbetweentemperatureandtherelaxationtimeofscatteringintensityI(t)canbewelldescribedbytheWilliams-Landel-Ferry(WLF)function.
简介:Stress-dependenceoftheintrinsictimeofviscoelasticmaterialsisinvestigated.Theinfluenceofstresslevelontheintrinsictimeisconsideredtobesimilartothatoflemperature,pressure,solventcon-centration,damageandphysicalaging.Thetime-lemperature-stressequivalenceprincipleisproposed,byemployingwhich,thecreepcurvesatdifferenttemperaturesandstresslevelscanbeshiftedintoamastercurveatreferencetemperatureandstresslevel.Thusthelong-termcreepbehaviorofviscoelasticmaterialsatalowertemperatureandstresscanbepredictedfromtheshort-termoneatahighertemperatureandstress.Asanexample,thenonlinearcreepbehaviorofhigh-densitypolyethylene(HDPE)atroomtemperatureisstudiedusingthetime-temperature-stressequivalenceprinciplepresented.
简介:当学习节肢动物食肉动物猎物相互作用时,内脏内容分析是一个有用工具。我们使用了聚合酶链反应(PCR)检验在内脏的猎物脱氧核糖核酸的察觉怎么食肉动物满足的技术到消化时间和温度被影响。如此的知识在使用基于PCR的内脏内容分析回答前是批评的收集了食肉动物。two-spotted女士甲壳虫(AdaliabipunctataL.)的幼虫在21℃或14℃用鸟樱桃燕麦蚜虫(Rhopalosiphum垫iL.)被喂。在消费一个蚜虫以后,食肉动物被允许为时间时期的一个范围消化猎物直到24个小时。A上的温度的影响。喂行为的bipunctata也被记录。从喂的幼虫,全部的脱氧核糖核酸被提取并且有R的PCR反应。垫i特定的教材被运用。A的数字。测试的bipunctata为R积极。垫i脱氧核糖核酸是否定地与消化时间的长度有关。温度影响了幼虫的喂的行为但是没在R上有重要效果。填i脱氧核糖核酸察觉。在从两个温度处理分享数据以后,我们估计了时间点什么时候R。垫i脱氧核糖核酸能从50%喂的A被放大。由PCR到的bipunctata是4.87个小时。与在猎物脱氧核糖核酸察觉成功的如此的快速的减少,积极PCR反应将很可能是立即在俘获前发生的捕食事件的结果。如果一个定义消化温度范围证明了不影响猎物察觉,从食肉动物获得的PCR数据在那个特别范围以内收集了能以一样的方法被解释。
简介:AseriesofPr-CothinfilmsweredepositedontheSi(100)substrateswithCrunderlayerbymagnetronsputtering.Theeffectsofboththepost-annealingtemperatureandtheannealingtimeonthemicrostructureandmagneticpropertiesforthePr-Cofilmswerestudiedsystematically.Theas-depositedPr-Cothinfilmsaremostlyamorphousandtendtocrystallizeafterannealingattemperaturesabove600℃.Whentheannealingtimeisincreased,thefilmsshowacomplicatedstructurewithvariousphasesco-existing.Accordingly,theas-depositedfilmandlowtemperatureannealedfilmsaresoftmagnetsandfilmsannealedattemperaturesbeyond600℃tendtobehardmagnets.Whentheannealingtimeisincreasedfrom5minto2h,thefilmstransferfromhardmagnetstosoftagain.Thesampleannealedat600℃for10minshowsthelargestcoercivityof0.59T.
简介:TheZnOquantumdots(QDs)weresynthesizedwithimprovedchemicalsolutionmethod.ThesizeoftheZnOQDsisexceedinglyuniformwithadiameterofapproximately4.8nm,whicharehomogeneouslydispersedinethanol.Theopticalabsorptionedgeshiftsfrom370nmofbulkmaterialto359nmofQDmaterialsduetothequantumsizeeffect,whilethephotoluminescencepeakshiftsfrom375nmto387nmwiththeincreaseofthedensityofZnOQDs.ThestabilityofZnOQDswasstudiedwithdifferentdispersiondegreesat0?Candatroomtemperatureof25?C.Theagglomerationmechanismsandtheirrelationshipwiththeemissionspectrawereuncoveredforthefirsttime.WiththeageingofZnOQDs,theagglomerationisaggravatedandthesurfacedefectsincrease,whichleadstothedefectemission.
简介:基于三个全球年度吝啬的表面温度时间系列和三个中国年度平均数表面空气温度时间系列,多重timescales上的气候变化趋势被使用多滑动的时间窗户的趋势评价方法分析。结果被用来在1998-2012期间讨论所谓的全球温暖的中断。不同开始和结束时间在趋势评价的结果上有明显的效果,这被表明,并且当使用一扇短窗户时,含意特别地大。全球温暖的中断在1998-2012期间是在短timescales上看温度系列的结果;并且类似于它的事件,或有甚至冷的趋势的事件,实际上历史上多次发生了。因此,全球温暖的中断是可能的是长期的温度变化的一个期刊特征。它主要在短学期反映温度,和如此的现象的十的可变性不从长远的观点看改变全面温暖趋势。
简介:Theeffectofsinteringdispersedandbulk,lowmolecularweight(Mn=50,000Da),nano-emulsionpolytetrafluoroethylene(PTFE)particlesneartheirmeltingpointisdescribed.Withthenascentparticlesconsistingofca.75nmdiameter,hexagonal,singlecrystals,sinteringat,e.g.,350℃,results,initially,inmergerofneighboringparticles,followedbyindividualmolecularmotiononthesubstrateandtheformationoffoldedchain,lamellarsinglecrystalsandspherulites,andon-edgeribbons.Itissuggestedthesestructuresdevelop,withtime,inthemesomorphic'melt'.Sinteringofthebulkresinyieldsextendedchain,bandstructures,aswellasfoldedchainlamellae;end-surfacetoend-surfacemerger,possiblybyend-to-endpolymerization,occurswithincreasingtime.
简介:作为一种试验性的技术,它的需要在标本的温度在高温度裂口Hopkinson压力酒吧(SHPB)中是一致的,这试验。然而,当标本开始到时,在标本减少的温度和酒吧的温度增加与酒吧联系,它在标本导致不一致的温度分发,并且可以导致试验性的结果的不确。在这份报纸,当标本独自被加热时,在高温度SHPB实验的标本和酒吧的温度分布被调查。第一,标本的温度历史被实验在不同起始的温度测量,然后,模拟被执行。模拟结果与由调整在标本和酒吧之间的热接触系数的试验性的结果一致。由这样,热接触系数和模拟结果被验证,并且合适的冷接触在高温度SHPB实验标本和酒吧预定被讨论。最后,结果与在参考书的那些相比。
简介:在到地震预言的MODIS卫星遥感数据的应用程序的学习,论文第一次提出一个量的方法与反常亮度温度(BT)为象素估计比率为云移动的增加和一个初步的计划。原则是第一,无云的数据在时间,但是在不同的天内的一样的时期由一样的卫星观察了(通常1天到3天)是mosaiced得到晴朗天空的高比率,然后BT变化曲线和每个象素的mcan平方差别(MSD)从盖住的区域与数据被计算每天决定今日的BT数据作为标准用两倍MSD在某个象素由是正常的。为有反常BT增加的象素的比率能被与整个区域的全部的象素划分反常象素的全部的数字计算。在台湾区域的一系列最近的地震上的分析证明为有反常BT增加的象素的比率,通常在零附近波动,有突然的改进1天到在媒介强壮的地震前的20天。为识别地震预兆的一个新方法能被从MODIS卫星遥感随反常BT增加为象素分析比率的变化与经常的地震活动在区域通过特殊研究发现,这被期望红外线(红外)云的效果从被移开的信息到某个程度。
简介:BasedonageneralanalysisofGreenfunctionsinthereal-timethermalfieldtheory,wehaveproventhatthefour-pointamputatedfunctionsinanNJLmodelinthefermionbubblediagramapproximationbehavelikeusualtwo-pointfunctions.WeexpoundthethermaltransformationsofthematrixpropagatorsforascalarboundstateintheFFbasisandintheRAbasisrespectively.Theresultingphysicalcausal,advancedandretardedpropagatorsarerespectivelyidenticaltocorrespondingonesderivedintheimaginary-timeformalism,andthisshowsonceagainthecompleteequivalenceofthetwoformalismsofthermalfieldtheoryonthediscussedproblemintheNJLmodel.
简介:TheresolutionexpressionforthetemperaturedependenceofthecurrentandthresholdvoltageisdeducedaswellastheanalysisoftemperaturecharacteristicsofBJMOSFET.EquivalentcircuitofanalysisandsimulationhasbeenestablishedfortheBJMOSFETtemperaturecharacteristics.ByusingthegeneralcircuitsimulationsoftwareofPSpice9andcomputersimulation,characteristicgraphsoftheBJMOSFEToutputcharacteristic,transientcharacteristicandamplitude-frequencycharacteristicwithtemperaturevariationareobtained.TheresultsaccordedverygoodwiththeoreticalanalysisandprovedthatBJMOSFEThasbettertemperaturecharacteristicsthantraditionalMOSFET.
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.