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173 个结果
  • 简介:描述了剪切敏感液晶涂层(shear-sensitiveliquidcrystalcoatings,SSLCCs)在高超声速风洞中针对三角翼模进行表面摩擦阻力(简称摩阻)测量的应用情况.建立了基于剪切敏感液晶涂层光学测量系统,在中国航天空气动力技术研究院FD-07风洞中进行了三角翼摩阻测量实验,给出了三角翼表面摩阻分布数据,表明流场结构的复杂.实验结果证明了此方法进行高超声速摩阻测量的可行性,有效解决了在高超声速流场条件下表面摩阻预测的难题,具有重要的应用价值.

  • 标签: 剪切敏感液晶涂层 剪切应力测量 平板三角翼 高超声速流场
  • 简介:Theeffectofbismuth(Bi)forbothVO2+/VO2+andV3+/V2+redoxcouplesinvanadiumflowbatteries(VFBs)hasbeeninvestigatedbydirectlyintroducingBionthesurfaceofcarbonfelt(CF).TheresultsshowthatBihasnocatalyticeffectforVO2+/VO2+redoxcouple.Duringthefirstchargeprocess,BiisoxidizedtoBi3+(neverreturnbacktoBimetalinthesubsequentcycles)duetothelowstandardredoxpotentialof0.308V(vs.SHE)forBi3+/BiredoxcouplecomparedwithVO2+/VO2+redoxcoupleandBi3+exhibitno(orneglectable)electro-catalyticactivity.Additionally,therelationshipbetweenBiloadingandelectrochemicalactivityforV3+/V2+redoxcouplewasstudiedindetail.2wt%Bi-modifiedcarbonfelt(2%-BiCF)exhibitsthehighestelectrochemicalactivity.Usingitasnegativeelectrode,ahighenergyefficiency(EE)of79.0%canbeachievedatahighcurrentdensityof160mA/cm2,whichis5.5%higherthanthepristineone.Moreover,theelectrolyteutilizationratioisalsoincreasedbymorethan30%.Eventhecelloperatedat140mA/cm2forover300cycles,theEEcanreach80.9%withoutobviousfluctuationandattenuation,suggestingexcellentcatalyticactivityandelectrochemicalstabilityinVFBs.

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  • 简介:1教学分析1.1背景介绍2016年6月21日由中华中学上新河初中携学区内金陵中学实验小学、中华中学附属小学启动学区制管理实践——“上新河论坛”,首次论坛聚焦课堂教学方式的中小学衔接,开设数学专场研讨.本课例是这次研讨活动的课堂实录.旨在通过“正数负数”的课堂教学对中小学数学衔接教学实践做些尝试.1.2教材分析本课内容是在小学初步了解正数和负数的意义的基础上展开的,

  • 标签: 中小学数学 上新河 金陵中学 课堂教学方式 课堂实录 教学效果
  • 简介:Weproposeandexperimentallydemonstratea2×2thermo-optic(TO)crossbarswitchimplementedbydualphotoniccrystalnanobeam(PCN)cavitieswithinasilicon-on-insulator(SOI)platform.Bythermallytuningtherefractiveindexofsilicon,theresonancewavelengthofthePCNcavitiescanbered-shifted.WiththehelpoftheultrasmallmodevolumesofthePCNcavities,only~0.16mWpowerisneededtochangetheswitchingstate.Withaspectralpassbandof0.09nmatthe1583.75nmoperationwavelength,theinsertionloss(IL)andcrosstalk(CT)performancesweremeasuredasIL(bar)=-0.2dB,CT(bar)=-15dB,IL(cross)=-1.5dB,andCT(cross)=-15dB.Furthermore,thethermaltuningefficiencyofthefabricateddeviceisashighas1.23nm/mW.

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  • 简介:Theneworganic-inorganiccompound,[C_6H_7N_2O_2]_3TeCl_5·2Clwassynthesizedanditsstructurewasdeterminedatroomtemperatureinthetriclinicsystem(P~-1)withthefollowingparameters:a=10.5330(11)?,b=10.6663(11)?,c=15.9751(16)?,α=82.090(2)°,β=71.193(2)°,γ=68.284(2)°andZ=2.ThefinalcycleofrefinementledtoR=0.057andRw=0.149.ThecrystalstructurewasstabilizedbyanextensivenetworkofN--H···Clandnon-classicalC--H···Clhydrogenbondsbetweenthecationandtheanionicgroup.Severalthermalanalysistechniquessuchasthermogravimetricanalysis,differentialscanningcalorimetricanalysisandevolvedgasanalysiswereused.Weusedisoconversionalkineticsmethodstodeterminethekineticsparameters.Weobservethatthedecompositionof[C_6H_7N_2O_2]_3TeCl_5·2Clentailstheformationhydrochloricacidofnitroanilineasvolatiles.Theinfraredspectrawererecordedinthe4000–400cm~(-1)frequencyregion.TheRamanspectrawererecordedintheexternalregionoftheanionicsublatticevibration50–1500cm~(-1).TheopticalbandgapwascalculatedfromtheUV-VisabsorbancespectrausingclassicalTaucrelationwhichwasfoundtobe3.12and3.67eV.

  • 标签: 结构分析 光学性质 合成 化合物 紫外-可见吸收光谱 差示扫描量热分析
  • 简介:Thispapercontainsadetailed,selfcontainedandmorestreamlinedproofofthel~2decouplingtheoremforhypersurfacesfromthepaperofBourgainandDemeterin2015.TheauthorshopethiswillserveasagoodwarmupforthereadersinterestedinunderstandingtheproofofVinogradov'smeanvaluetheoremfromthepaperofBourgain,DemeterandGuthin2015.

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  • 简介:Mode-andpolarization-divisionmultiplexingoffernewdimensionstoincreasethetransmissioncapacityofopticalcommunications.Selectiveswitchesarekeycomponentsinreconfigurableopticalnetworknodes.Anon-chipsilicon2×2mode-andpolarization-selectiveswitchthatcanroutefourdatachannelsontwomodesandtwopolarizationssimultaneouslyisproposedandexperimentallydemonstratedforthefirsttime,tothebestofourknowledge.Theoverallinsertionlossesarelowerthan8.6dB.Toreducetheinter-modalcrosstalk,polarizationbeamsplittersareaddedtofiltertheundesiredpolarizationsormodes.Themeasuredinter-modalandintra-modalcrosstalkvaluesarebelow-23.2and-22.8dBforallthechannels,respectively.

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  • 简介:TheAlkalineThermalTreatment(ATT)ofbiomassisoneofthefewbiomassconversionprocessesthathasapotentialforBECCS(bio-energywithcarboncaptureandstorage).Combiningin-situcarboncapturewithcreatesacarbon-neutralprocessthathasthepotentialtobecarbon-negative.Thisstudyhasshownthattheconversionofcellulosetosuppressedcanbeachievedthroughthereformingofgaseousintermediatesinafixedbedof10%Ni/ZrO2.Reformingoccursatlowtemperatures≤773K,whichcouldallowforimprovedsustainability.

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  • 简介:对《基于数据的Goodgrant基金最优投资策略》一文使用主成分分析进行综合评价,对候选学校绩效指标值排名进行了探讨。首先,综合前人研究本题实际,指出使用主成分分析进行综合评价存在的争议不足;然后,分别建立TOPSIS模型和综合评价模型对候选学校的绩效指标值进行排名,并对不同方法得到的结果进行对比。结果表明,TOPSIS模型和综合评价模型得到的排名具有高度一致性,前50名重合率达98%,而与主成分分析综合评价的重合率仅有6%,说明使用TOPSIS等传统评价模型对候选学校绩效指标值进行排名更合适。

  • 标签: 主成分分析 TOPSIS模型 综合评价法
  • 简介:强壮的苏(2)计量器chromoelectric领域里的费米子粒子对生产以一个古典方法用Boltzmann-Vlasov方程被学习。在古典描述的一个preproduction过程的存在用non-Abelian粒子生产的分发进化被显示出。发现粒子数字密度的分发在二个岛上被集中并且当它演变,在颜色费用范围上显示出一个裂口有趣,最终到达这个领域的振幅和变化有关的一个稳定的状态。

  • 标签: SU(2) 背景场 BOLTZMANN Vlasov方程 粒子数密度 试制过程
  • 简介:目的:探究季铵型聚合物CO2解吸附过程温度和CO2浓度等变量对解吸附热力学和动力学的影响;研究空气CO2捕集供给植物增产的耦合方法,降低空气CO2捕集利用的能耗成本。创新点:1.基于变湿吸附技术,探究了季铵型聚合物CO2解吸附过程的热力学及动力学特性;2.获得了CO2作为气肥供给植物增产的关键影响参数;3.建立并优化了空气CO2捕集植物利用的耦合模型。方法:1.通过CO2吸附平衡动力学实验,获得季铵型聚合物CO2解吸附的平衡常数和动力学常数的影响参数;2.通过植物CO2吸收实验,获得CO2供给植物增产过程中CO2浓度和光照强度对吸收速率的影响;3.通过理论推导,构建解吸附CO2浓度吸附剂质量、温度以及吹扫气流量等的关系,获得空气CO2捕集植物增产的耦合模型并计算CO2捕集的能耗成本。结论:1.季铵型聚合物材料吸附CO2的平衡常数随温度的升高而降低;吸附、解吸附动力学常数随温度的升高而升高。2.CO2供给植物增产的最佳浓度和光照强度为1000ppm和8000lux。3.基于优化的空气捕集植物利用的耦合算法,CO2的捕集能耗成本分别为35.67kJ/mol和34.68USD/t。

  • 标签: 直接空气捕集 解吸附动力学 温室 CO2气肥 成本分析
  • 简介:Hydrogen,thecleanestandmostpromisingenergyvector,canbeproducedbysolarintochemicalenergyconversion,eitherbythephotocatalyticdirectsplittingofwaterintoH2andO2,or,moreefficiently,inthepresenceofsacrificialreagents,e.g.,intheso-calledphotoreformingoforganics.Efficientphotocatalyticmaterialsshouldnotonlybeabletoexploitsolarradiationtoproduceelectron–holepairs,butalsoensureenoughchargeseparationtoallowelectrontransferreactions,leadingtosolarenergydriventhermodynamicallyup-hillprocesses.RecentachievementsofourresearchgroupinthedevelopmentandtestingofinnovativeTiO2-basedphotocatalyticmaterialsarepresentedhere,togetherwithanoverviewonthemechanisticaspectsofwaterphotosplittingandphotoreformingoforganics.Photocatalyticmaterialswereeither(i)obtainedbysurfacemodificationofcommercialphotocatalysts,orproduced(ii)inpowderformbydifferenttechniques,includingtraditionalsolgelsynthesis,aimingatengineeringtheirelectronicstructure,andflamespraypyrolysisstartingfromorganicsolutionsoftheprecursors,or(iii)inintegratedform,toproducephotoelectrodeswithindevices,byradiofrequencymagnetronsputteringorbyelectrochemicalgrowthofnanotubearchitectures,orphotocatalyticmembranes,bysupersonicclusterbeamdeposition.

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  • 简介:CO2capturewithionicliquids(ILs)hasattractedmanyattentions,andmostworksfocusedonabsorptionabilityatambienttemperatures,whileseldomresearchwasconcernedatelevatedtemperatures.ThisnotonlylimitstheCO2absorptionapplicationatelevatedtemperature,butalsothedeterminationoftheoperationconditionoftheCO2desorptiongenerallyoccurringathighertemperature.ThisworkmainlyreportedCO2solubilitiesinILsatelevatedtemperaturesandrelatedpropertieswerealsoprovided.1-alkyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide([CnMIm][Tf2N])ILswereselectedasphysicalabsorbentsforCO2captureinthisworkduetotheirrelativehigherCO2absorptioncapacitiesandgoodthermalstabilities.Thelong-termstabilitytestsshowedthat[CnMIm][Tf2N]isthermallystableat393.15Kforlongtime.CO2solubilitiesin[CnMIm][Tf2N]weresystematicallydeterminedattemperaturesfrom353.15Kto393.15K.ItdemonstratedthatCO2solubilityobviouslyincreaseswiththeincreaseofpressurewhileslightlydecreaseswithincreaseoftemperature.Asthelengthofalkylchainonthecationincreases,CO2solubilityinILsincreases.Additionally,thethermodynamicpropertiesincludingtheGibbsfreeenergy,enthalpy,andentropyofCO2werealsocalculated.

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  • 简介:Inthiswork,acidfunctionalizedmulti-wallcarbonnanotubes(MWCNTs)weremodifiedwithimidazolium-basedionicliquids.Theselectiveoxidationofvariousalcoholswithhydrogenperoxidecatalyzedby[PZnMo_2W_9O_(39)]~(5-),ZnPOM,supportedonionicliquids-modifiedwithMWCNTs,MWCNTAPIB,isreported.Thiscatalyst[ZnPOM@APIB-MWCNT],wascharacterizedbyX-raydiffraction,scanningelectronmicroscopy(SEM)andFT-IRspectroscopicmethods.Thisheterogeneouscatalystexhibitedhighstabilityandreusabilityintheoxidationreactionwithoutlossofitscatalyticperformance.

  • 标签: 多壁碳纳米管 离子液体 催化剂 多金属氧酸盐 氧化改性 H2O2
  • 简介:Co-electrolysisofCO2andH2Ousinghigh-temperaturesolidoxideelectrolysiscells(SOECs)intovaluablechemicalshasattractedgreatattentionsrecentlyduetothehighconversionandenergyefficiency,whichprovidesopportunitiesofreducingCO2emission,mitigatingglobalwarmingandstoringintermittentrenewableenergies.AsingleSOECtypicallyconsistsofanionconductingelectrolyte,ananodeandacathodewheretheco-electrolysisreactiontakesplace.Thehighoperatingtemperatureanddifficultactivatedcarbon-oxygendouble-bondofCO2putforwardstrictrequirementsforSOECcathode.Greateffortsarebeingdevotedtodevelopsuitablecathodematerialswithhighcatalyticactivityandexcellentlong-termstabilityforCO2/H2Oelectro-reduction.Thesofarcathodematerialdevelopmentisthekeypointofthisreviewandalternativestrategiesofhigh-performancecathodematerialpreparationisproposed.UnderstandingthemechanismofCO2/H2Oelectro-reductionisbeneficialtohighlyactivecathodedesignandoptimization.Thusthepossiblereactionmechanismisalsodiscussed.Especially,amethodincombinationwithelectrochemicalimpedancespectroscopy(EIS)measurement,distributionfunctionsofrelaxationtimes(DRT)calculation,complexnonlinearleastsquare(CNLS)fittingandoperandoambientpressureX-rayphotoelectronspectroscopy(APXPS)characterizationisintroducedtocorrectlydisclosethereactionmechanismofCO2/H2Oco-electrolysis.Finally,differentreactionmodesoftheCO2/H2OcoelectrolysisinSOECsaresummarizedtooffernewstrategiestoenhancetheCO2conversion.Otherwise,developingSOECsoperatingat300-600°CcanintegratetheelectrochemicalreductionandtheFischer-TropschreactiontoconverttheCO2/H2Ointomorevaluablechemicals,whichwillbeanewresearchdirectioninthefuture.

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  • 简介:Probingtheopticalpropertiesofmolybdenumdisulfide(MoS2)isvitaltoitsapplicationinplasmon-enhancedspectroscopy,catalysts,sensing,andoptoelectronicdevices.Inthispaper,wetheoreticallystudiedtheRamanandfluorescencepropertiesofmonolayerMoS2usingtip-enhancedspectroscopy(TES).Inthestrong-couplingTESsystem,theRamanandfluorescenceenhancementfactorscanbeturnedtoashighas4.5×108and3.3×103,respectively,byoptimizingthetip–MoS2-filmdistance.OurtheoreticalresultsnotonlyhelptodeeplyunderstandtheTESpropertiesofmonolayerMoS2,butalsoprovidebetterguidanceontheapplicationsofthenoveltwo-dimensionalmaterial.

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