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  • 简介:研究目的:研究新型磁性回热填料Gd2O2S对液氦温区高频脉管制冷机多级回热器损失特性的影响。创新要点:确定了不同回热填料以及运行参数(频率、平均压力)下液氦温区多级脉管制冷机的制冷温度和各级预冷量,进一步明确了4K高频回热损失机理。研究方法:采用理论研究与实验验证相结合的方法,基于一台两级G-M型低频脉管制冷机预冷的单极斯特林型高频脉管制冷机,研究多级回热器在高频以及4K温区下的损失特性。选取新型回热填料Gd2O2S替代部分回热填料HoCu2,比较回热器采用两种填料时在不吲运行频率及平均压力下的冷端制冷温度(图10)、各级预冷量和预冷温度(图1112)。重要结论:采用孔隙率较小的新型磁性回热填料Gd2O2S可显著改善第一级回热器内压力波与质量流的相位关系,从而减小该级回热损失。减小平均压力可以降低制冷机无负荷制冷温度并减小第二级预冷量,但制冷工质氦的体积比热容会急剧增大,从而使低温级回热器的换热对频率非常敏感。此外,频率对高温级回热器的回热特性影响不明显。该方法可以为三级斯特林型4K多级脉管制冷机提供设计依据。

  • 标签: 斯特林型脉管制冷机 回热填料 4K 高频 预冷 低温惯性管
  • 简介:Weexperimentallydemonstratea4×4nonblockingsiliconthermo-optic(TO)switchfabricconsistingofthreestagesoftunablegeneralizedMach–Zehnderinterferometers.All24routingstatesfornonblockingswitchingarecharacterized.Thedevice’sfootprintis4.6mm×1.0mm.Measurementsshowthattheworstcrosstalkofallswitchingstatesis-7.2dB.Theon-chipinsertionlossisintherangeof3.7–13.1dB.TheaverageTOswitchingpowerconsumptionis104.8mW.

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  • 简介:Generallyspeaking,mainflowpathofgasturbineisassumedtobeperfectforstandard3Dcomputation.Butinrealengine,theturbineannulusgeometryisnotcompletelysmoothforthepresenceoftheshroudandassociatedcavityneartheendwall.Besides,shroudleakageflowisoneofthedominantsourcesofsecondaryflowinturbomachinery,whichnotonlycausesadeteriorationofusefulworkbutalsoapenaltyonturbineefficiency.Ithasbeenfoundthatneglectshroudleakageflowmakesthecomputedvelocityprofilesandlossdistributionsignificantlydifferenttothosemeasured.Evenso,theinfluenceofshroudleakageflowisseldomtakenintoconsiderationduringtheroutineofturbinedesignduetoinsufficientunderstandingofitsimpactonendwallflowsandturbineperformance.Inordertoevaluatetheimpactoftipshroudgeometryonturbineperformance,a3Dcomputationalinvestigationfor1.5-stageturbinewithshroudedbladeswasperformedinthispaper.Thefollowinggeometryparameterswerevariedrespectively:-Inletcavitylengthandexitcavitylength,-Shroudoverhangupstreamoftherotorleadingedgeanddownstreamofthetrailingedge,-Shroudradialtipclearance,Theaimofthispaperistoisolatetheinfluenceofshroudandcavitygeometrymodificationsonturbineaerodynamicperformanceandtoobtaincleartrendsofefficiencychangescausedbydifferenttipshroudgeometry.Moreover,interactionbetweenleakageflowandmainstreamfordifferentshroudconfigurationisalsohighlightedinordertopenetrateintothephysicalmechanismsproducingthem.Duetothelimitationsofthemodelselectedinthispaper,theaimofresearchisnottoputforwardthedesignrulesofturbineshroud.However,theresultsobtainedfromthisworkwillbeusefultotheintegrateddesignandoptimizationofturbinewithshroudedblades.

  • 标签: 燃气涡轮机 几何形状 性能影响 计算量 高负荷 轮罩
  • 简介:Aseriesofoxygenpermeabledual-phasecompositeoxides60wt%Ce0.8Gd0.2O2-δ-40wt%LnBaCo2O5+δ(CGO-LBCO,Ln=La,Pr,Nd,Sm,GdandY)weresynthesizedthroughasol-gelrouteandeffectsoftheLn3+cationsontheirphasestructure,oxygenpermeabilityandchemicalstabilityagainstCO2wereinvestigatedsystemicallybyXRD,SEM,TG-DSCandoxygenpermeationexperiments.XRDpatternsrevealthatthelargerLn3+cations(La3+,Pr3+andNd3+)successfullystabilizedthedouble-layeredperovskitestructureofsinteredLBCO,whilethesmallerones(Sm3+,Gd3+,andY3+)resultedinthepartialdecompositionofLBCOwithsomeimpuritiesformed.CGO-PBCOyieldsthehighestoxygenpermeationflux,reaching2.8×10-7mols-1cm-2at925?Cwith1mmthicknessunderair/Hegradient.TheTG-DSCprofilesin20mol%CO2/N2andoxygenpermeabilityexperimentswithCO2assweepgasshowthatCGO-YBCOdemonstratesthebestchemicalstabilityagainstCO2,possiblyduetoitsminimumbasicity.ThestableoxygenpermeationfluxofCGO-YBCOunderCO2atmosphererevealsitspotentialapplicationintheoxy-fuelcombustionrouteforCO2capture.

  • 标签: CO2 透氧性 双相 化学稳定性 TG-DSC 渗透实验
  • 简介:On △I= Bifurcation PhenomenaOn△I=BifurcationPhenomena¥ZhangJingye;YangSunandMikeGuidryTheexperiments-bythenew7--raydetector...

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  • 简介:TomoreindepthunderstandthedopingeffectsofoxygenonSiGealloys,boththemicro-structureandpropertiesofO-dopedSiGe(including:bulk,(001)surface,and(110)surface)arecalculatedbyDFT+Umethodinthepresentwork.Thecalculatedresultsareasfollows.(i)The(110)surfaceisthemainexposingsurfaceofSiGe,inwhichOimpuritypreferstooccupythesurfacevacancysites.(ii)ForOinterstitialdopingonSiGe(110)surface,theexistencesofenergystatescausedbyOdopinginthebandgapnotonlyenhancetheinfraredlightabsorption,butalsoimprovethebehaviorsofphoto-generatedcarriers.(iii)ThefindingaboutdecreasedsurfaceworkfunctionofO-dopedSiGe(110)surfacecanconfirmpreviousexperimentalobservations.(iv)Inallcases,Odoingmainlyinducestheelectronicstructuresnearthebandgaptovary,butisnotdirectlyinvolvedinthesevariations.Therefore,thesefindingsinthepresentworknotonlycanprovidefurtherexplanationandanalysisforthecorrespondingunderlyingmechanismforsomeoftheexperimentalfindingsreportedintheliterature,butalsoconducetothedevelopmentofμc-SiGe-basedsolarcellsinthefuture.

  • 标签: SIGE 计算结果 电子结构 掺杂 O型 锗硅合金
  • 简介:合成了六铝酸盐SrNiAl11O19并用XRD、UVDRS、TGDTA和TEM等技术对其进行了表征。在750℃于SrNiAl11O19上进行的甲烷与二氧化碳重整反应表明,这类催化剂较Ni/SrAl12O19具有较大活性和低积碳能力,在催化反应过程中可有效地抑制Ni颗粒的增大。

  • 标签: 六铝酸盐甲烷重整Ni催化剂
  • 简介:TheNd2O3nanoparticleswhichmodifiedbyAOTwaspreparedusingmicrioemulsionmethodinthesystemofwater/xylene.L3edgeXAFSwasusedtodeterminethedifferenceofthelocalstructurearundNd^3+ionandtheelectricalstructurebetweenthenanocystallineNd2O3andthecoarsebulkmicrocrystallineNd2O3.ItwasfoundthatNd-Odistanceincreasedwiththeformofnanocrystalliteandtheintensityofabsorptionedgealsoenhancedatthesametime.

  • 标签: EXAFS研究 ND2O3 毫微米粒子
  • 简介:我们介绍自发的对称碎在Pati之间的acouplingbetween的顺序—Salam和电镀物品弱对称苏(4)_(PS)直接X苏(4)_(EW)可伸缩以便在宏大统一精力在联合常数之中建立一种算术地一致的关系。与减已知的夸克和雷普顿的雷普顿量数字那里的酒吧的价值,由传递includingright的中微子,我们能在直到电磁的U(1)_(他们)的层次放大的不同精力发现混合角度关系。

  • 标签: 电弱模型 统一化对称 规范对称 耦合常数
  • 简介:Therearemoreandmorecountriestoakeanefforttothestudiesofvanadiumalloyforfusionapplication.NIFSinJapanhasrecentlydevelopedan80kgheatV4Cr4Tialloy(NIFS-heat2)aftertheproductionofa500kgscaleV4Cr4TiinU.S.severalyearsago.PropertyevaluationofthealloyhasbeenputintoaninternationalcollaborationprogramunderthecoordinationofIEA(InternationalEnergyAgency).SWIPhasjoinedthecollabrationonthehydrogenembrittlementresistanceevaluationofthealloyt.

  • 标签: 钒合金 氢脆变 阻抗 NIFS
  • 简介:ThedevelopmentoftheGEANT4applicationforALICEsimulationwithinthealiRootframeworkisdescribed.TheG3toG4approachadoptedbyALICEcollaborationisexplained.Theoverviewofthedesign,presentimplementationandfunctionalityispresentedandtheremainingproblemsarediscussed.

  • 标签: ALICE实验 软件开发 GEANT4
  • 简介:SinceitserliestyearsofR&D[1],theGEANT4simulationtoolkithasbeendevelopedfollowingsoftwareprocessstandardswhichdictatedtheoverallevolutionoftheproject.Thecomplexityofthesoftwareinvolved,thewideareasofapplicationofthesoftwareproduct,thehugeamountofcodeandCategorycomplexity,thesizeanddistributednatureoftheCollaborationitselfareallingredientswhichinvolveandcorrelatetogetherawidevarietyofsoftwareprocesses.Althoughin"production"andavailabletothepublicsinceDecember1998,theGEANT4softwareproduct[1]includesCategoryDomainswhicharestillunderactivedevelopment.Thereforetheyrequiredifferenttreatmentalsointermsofimprovementofthedevelopmentcycle,system,testingandusersupport,ThisarticleismeanttodescribesomeofthesoftwareprocessesastheyareappliedinGEANT4forbothdevelopment,testingandmaintenanceofthesoftware.

  • 标签: GEANT4 软件处理 软件开发
  • 简介:本文首次采用高温高压固相反应法合成类钙钛矿化合物Ba1-xLaxTiO3(x=0.0,0.1,0.2,0.3,0.4,0.5)。XRD谱的测量结果表明,在压力为2.8GPa,温度为850℃下,稀土La在BaTiO3中的替代导致结构从立方到四方到正交的结构转变,因此,Ba1-xLaxTiO3体系体现结构转变规律和丰富的物相结构。

  • 标签: XRD 结构相变 晶格畸变 高温高压合成
  • 简介:Vanadiumalloys(V-Cr-Tiseries)areimportantcandidatematerialsforblanketcomponentsoffusionreactorsduetotheirlowactivationandhighstrengthatelevatedtemperatures.Low-temperatureirradiationembrittlementdeterminestheoperationtemperaturelimitofVanadiumalloysfortheapplicationtostructuralmaterialsoffusionreactorsirradiationresponseofvanadiumalloysneedstobeclarifiedfortheirapplication.Inthepresentstudy,specimensoftwoalloys(V-4Cr-4TiandV-5Cr-5Ti)wereirradiatedwithenergeticHeionsandheavyionstounderstandhardeningofthealloysduetoheliumaccumulationandcascadedamageproduction.

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