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500 个结果
  • 简介:ResultsofinelasticneutronscatteringexperinientsandabinitiomoleculardynamicssimulationsforGeTe一theparentcompoundofphase-changematerialsarereported.TheinelasticneutronspectraofGeTepowdersampleshavebeendeterminedinthetemperaturerangeextendingfrom300to700K.Thephononpeaksundergothermalshiftsresultingfromanharmoniceffectsbeingweakerforacousticthanopticmodes.AsmallconcentrationoffreechargecarriesarisingfromthepresenceofGe-vacancieswasfoundnottoaffectsignificantlytheneutronweightedphonondensitiesofstatesofGeTe.Thespectralpatternchangesqualitativelyacrossthestructuralphasetransition,butthelocalstructureofGeTeremainshardlyaffected,asconfirmedbytheanalysisoftemperaturedependenceofthepairdistributionfunctionobtainedfromabinitiomoleculardynamicsinvestigations.Thepresenttheoreticalstudiessupportinawideextentourexperimentalobservationsandalsothoseprovidedbylocalprobemethods.

  • 标签: PHASE-CHANGE MAT erials INELASTIC neutron scattering
  • 简介:Atunableplasmonicperfectabsorberwithatuningrangeof650nmisrealizedbyintroducinga20nmthickphase-changematerialGe2Sb2Te5layerintothemetal–dielectric–metalconfiguration.Theabsorptionattheplasmonicresonanceiskeptabove0.96acrossthewholetuningrange.Inthisworkwestudythisextraordinaryopticalresponsenumericallyandrevealthegeometricconditionswhichsupportthisphenomenon.Thisworkshowsapromisingroutetoachievetunableplasmonicdevicesformulti-bandopticalmodulation,communication,andthermalimaging.

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  • 简介:Wenumericallydemonstrateanovelultra-broadbandpolarization-independentmetamaterialperfectabsorberinthevisibleandnear-infraredregioninvolvingthephase-changematerialGe2Sb2Te5(GST).Thenovelperfectabsorberschemeconsistsofanarrayofhigh-indexstrong-absorbanceGSTsquareresonatorsseparatedfromacontinuousAusubstratebyalow-indexlosslessdielectriclayer(silica)andahigh-indexGSTplanarcavity.Threeabsorptionpeakswiththemaximalabsorbanceupto99.94%areachieved,owingtotheexcitationofplasmon-likedipolarorquadrupoleresonancesfromthehigh-indexGSTresonatorsandcavityresonancesgeneratedbytheGSTplanarcavity.Theintensitiesandpositionsoftheabsorptionpeaksshowstrongdependenceonstructuralparameters.AheattransfermodelisusedtoinvestigatethetemporalvariationoftemperaturewithintheGSTregion.TheresultsshowthatthetemperatureofamorphousGSTcanreachupto433Kofthephasetransitiontemperaturefromroomtemperatureinjust0.37nswitharelativelylowincidentlightintensityof1.11×108W∕m2,duetotheenhancedultra-broadbandlightabsorbancethroughstrongplasmonresonancesandcavityresonanceintheabsorber.Thestudysuggestsafeasiblemeanstolowerthepowerrequirementsforphotonicdevicesbasedonathermalphasechangeviaengineeringultra-broadbandlightabsorbers.

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  • 简介:做Si的Ge(2)sb(2)Te(5)电影被dc劈啪作响magnetronco与Ge2Sb2Te5和Si目标准备了。在在两结晶化温度和阶段转变温度fromface-centred-cubic(fcc)的增加的Te(5)电影结果分阶段执行到的Ge(2)sb(2)的Si的增加六角形(十六进制)阶段。Ge2Sb2Te5电影的抵抗力显示出重要增加,Si做。当在这部电影做Si的11.8at.%时,在退火的460度C以后的抵抗力与undopedGe2Sb2Te5电影相比从64~99终止从1~11m终止(.)厘米和动态抵抗增加增加。这对写阶段变化随机存取记忆的当前的减小很有用。

  • 标签: GE2SB2TE5薄膜 掺杂 随机存储 相变 结晶温度
  • 简介:Thisworkbrieflysummarizedtherecentresearcheffortsmadeonthephaseheattransferprocessesinvolvingbiologicalaggregates,withparticularattentiononthecorrelationofaggregatestructureandstateofwaterwiththeprocessefficiency.Thephasechangeprocessesincludeboiling,drying,freezing,sintering,pyrolysis,andsupercriticalextraction,whiletheformerthreewerediscussedinsomedetail.

  • 标签: PHASE-CHANGE AGGREGATES FRACTAL STRUCTURES BOUND water.
  • 简介:这短通讯通过一个一步舞方法作为壳材料用硅石在阶段变化材料的microcapsules的合成和描述上报导我们的最近的工作。方法不为stabilising使用表面活化剂或分散剂囊。结果证明一步舞方法允许调节不同核心材料的囊,和使用的尺寸和多分散性。囊的分析证明他们包含大约65%阶段变化材料。结果也不由胺组由于self-stabilisation为一个stabilising代理人建议需要。进一步的工作是在进行之中的调查microcapsules的机械、热的性质和方法的按比例增加。

  • 标签: 微胶囊相变材料 一步法 生产 表面活性剂 稳定剂 硅材料
  • 简介:Anewcompositioncontentquaternary-alloy-basedphasechangethinfilm,Sb-richAglnSbTe,hasbeenpreparedbyDC-magnetronsputteringonaK9glasssubstrate.Afterthefilmhasbeensubsequentlyannealedat200℃for30min,itbecomesacrystallinethinfilm.Thediffractionpeakofantimony(Sb)areobservedbyshallow(0.5degree)x-raydiffractioninthequaternaryalloythinfilm.Theanalysesofthemeasurementfromdifferentialscanningcalorimetry(DSC)showthatthecrystallizationtemperatureofthephasechangethinfilmisabout190℃andincreaseswiththeheatingrate.ByKissingerplot,theactivationenergyforcrystallizationisdeterminedtobe3.05eV.Thereflectivity,refractiveindexandextinctioncoefficientofthecrystallineandamorphousphasechangethinfilmsarepresented.Theopticalabsorptioncoefficientofthephasechangethinfilmsasafunctionofphotonenergyisobtainedfromtheextinctioncoefficient.Theopticalbandgapsoftheamorphousandcrystallizationphasechangethinfilmsare0.265eVand1.127eV,respectively.

  • 标签: 薄膜物理学 相位变换 光学数据存储 杂质添加
  • 简介:ZrO2nanopowdersbasedstearicacidphasechangematerials(PCMs)werepreparedbyhigh-energymilling.Theconceptofheatcapacityfactor(HCF)wasusedtoanalyzethethermalpropertiesofthematerials.TheheatstoragepropertyofPCMs,containingthesamecontentofstearicacid(23%bymass)inthestartingmaterialsbutsynthesizedbydifferenttechnicalprocesses,wasinvestigatedbyusingHCF.Itwasfoundthattherewerevastinfluencesofdifferentdispersantsontheheatcapacity.Thesamplespreparedwithchloroformprovidedthebestheatstorageabilityinallsamplestested.

  • 标签: 相变材料 纳米粉体 硬脂酸 氧化锆 基础研究 蓄热性能
  • 简介:High-temperaturePhaseChangeMaterial(PCM)isusedasathermalstoragemediumofaheat-pipereceiverinanadvancedsolardynamicsystem.Withbothvoidcavityandnaturalconvectionconsidered,thermalperformanceoftheheat-pipereceiverisnumericallyanalyzedundergravity.TheresultsindicatethatthePCMcontainedintheintegratedheatpipeperformsanaveragingfunctionofheatloadings.Thethermalperformanceoftheheat-pipereceiverisstableandreliable.Whenaheatingcycleisstable,thetemperaturefluctuationsbothonheat-pipewallandinPCMcanisterremainlessthan13Kthroughoutasunlightandeclipsecycle.TheutilityofPCMisessentiallyimproved.ThemaximummeltingratioofPCMis92%.Undergravity,PCMmeltsmorequicklywiththeeffectofnaturalconvection.Naturalconvectionacceleratestheprocessofphasechanges.Numericalresultsarecomparedwiththeexperimentalresultsconcerned.Theaccuracyofnumericalmodelundergravityisverified.TheexperimentforthePCMcanisteronthegroundcanbewellpreparedwithournumericalsimulation.

  • 标签: 重力作用 相变材料 瞬态热分析 热管 二维 吸热
  • 简介:Anewpotassiumnitrate(KNO_3)/diatomiteshape-stabilizedcompositephasechangematerial(SSCPCM)waspreparedbythemixingandsinteringmethod.KNO_3servedasthephasechangematerial(PCM)forthermalenergystorage,whilediatomiteactedasthecarriermatrixtoprovidethestructuralstrengthandpreventtheleakageofPCM.ItwasfoundthatKNO_3couldberetained65wt%intoporesandonsurfacesofdiatomitewithouttheleakageofmeltedKNO_3fromtheSS-CPCM.ThecalculatedfillingrateofmoltenKNO_3thatcouldenterintothedisc-likeshapeporeofdiatomiteverifiedthescanningelectronicmicroscopyimagesofSS-CPCM.X-raydiffractionandFouriertransforminfraredspectroscopyresultsshowedthatnoreactionoccurredbetweenKNO_3anddiatomite,performinggoodcompatibility.Accordingtothedifferentialscanningcalorimetryresults,after50thermalcycles,thephasechangetemperaturesformeltingandfreezingofSS-CPCMwith65wt%KNO_3werechangedfrom330.23°Cand332.90°Cto330.11°Cand332.84°Candcorrespondinglatentheatsvariedfrom60.52J/gand47.30J/gto54.64J/gand41.25J/g,respectively.TheKNO_3/diatomiteSS-CPCMmaybeconsideredasapotentialstoragemediainsolarpowerplantsforthermalenergystorage.

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  • 简介:ThisArticlepresentsathreedimensionalnumericalmodelinvestigatingthermalperformanceandhydrodynamicsfeaturesoftheconfinedslotjetimpingementusingslurryofNanoEncapsulatedPhaseChangeMaterial(NEPCM)asacoolant.Theslurryiscomposedofwaterasabasefluidandn-octadecaneNEPCMparticleswithmeandiameterof100nmsuspendedinit.AsinglephasefluidapproachisemployedtomodeltheNEPCMslurry.ThethermophysicalpropertiesoftheNEPCMslurryarecomputedusingmodernapproachesbeingproposedrecentlyandgoverningequationsaresolvedwithacommercialFiniteVolumebasedcode.TheeffectsofjetReynoldsnumbervaryingfrom100to600andparticlevolumefractionrangingfrom0%to28%areconsidered.ThecomputedresultsarevalidatedbycomparingNusseltnumbervaluesatstagnationpointwiththepreviouslypublishedresultswithwaterasworkingfluid.ItwasfoundthataddingNEPCMtothebasefluidresultswithconsiderableamountofheattransferenhancement.ThehighestvaluesofheattransfercoefficientsareobservedatH/W=4andC_m=0.28.However,duetothehigherviscosityofslurrycomparedwiththebasefluid,theslurrycanproducedrasticincreaseinpressuredropofthesystemthatincreaseswithNEPCMparticleloadingandjetReynoldsnumber.

  • 标签: 三维数值模型 相变材料 数值研究 浆料粘度 冲击冷却 射流
  • 简介:OnOctober1,wecelebratedour55thNationalDay.Inthepast55years,ongoingpovertyeradicationhasbeenamajoraspectofChina'ssteadydevelopment.ThisisapparentinareasasdiverseasXinjiang,ethnicautonomousregionsintheNorthwest,andFoshanCity,asmallbutdevelopedcityinGuangdongProvince,SouthChina.Bothbearwitnesstoremarkablechanges.

  • 标签: 新疆 佛山市 地方文化 工业经济 历史文化
  • 简介:Inthispaper,aWindDirectionChangeIndex(WI),whichcandescribefour-dimensionalspatiotemporalchangesoftheatmosphericcirculationobjectivelyandquantitatively,isdefinedtostudyitsevolutionandseasonalvariation.ThefirstfourmodescanbeobtainedbyEOFexpansionofthezonallyaveragedWI.ThefirstmoderevealsthebasicspatialdistributionoftheannuallyaveragedWI.Thesecondmodereflectsthequasi-harmonicpartsoftheWIdeviations.Tropical,subtropicalandextratropicalmonsoonareascanbeclearlyreflectedbythismode.Thethirdmodereflectsthenon-harmonicpartsoftheWIdeviations.Itshowstheso-calledFebruaryreverseinstratosphericatmosphereaswellastheasymmetricseasonalchangesfromspringtofallandfromfalltospringduetoboththeland-seadistributioncontrastbetweentheNorthernandSouthernHemispheresandthenonlineareffectofatmosphericandoceanfluids.Thefourthmoderevealsthenorthwardadvancingoftheglobalreversedwindfieldsfromspringtosummerandtheirsouthwardwithdrawalfromsummertoautumn.

  • 标签: 弯屈方向变化索引(WI ) 实验直角的功能(文件结束) 四维的时空变化 2 月同温层的颠倒
  • 简介:Si16Sb84-based线房间阶段变化随机存取记忆(PCRAM),在哪个Si16Sb84阶段变化线被听电极与nanoscale差距联系,被为重设操作的最低当前、测量的脉搏宽度是的电子横梁平版印刷术制作115μA和18ns,分别地为再结晶的测量最短的脉搏宽度是110ns,与1.5V的应用脉搏振幅。为有不同的线长度的线房间的集合和重设电流是坚定的。106的耐力与上面的电阻比率骑车800被完成了。

  • 标签: 低能耗相位 SiSb 薄膜 电极
  • 简介:【赏析】吉姆·罗恩是国际知名的商业思想家、美国JimRohn培训机构的创办人。他也是当今世界最受欢迎的企业界领袖之一,经常为顶级的销售组织和管理团队开办培训课程,并常受邀到全球各大企业去演讲。在这篇“改变始于选择”一文中,吉姆·罗恩把生活比喻成选择题,

  • 标签: 高校 英语 课外阅读 阅读材料