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500 个结果
  • 简介:Aseriesofamine-basedadsorbentsweresynthesizedusingsiliceousMCM-41individuallyimpregnatedwithfourdifferentamines(ethylenediamine(EDA),diethylenetriamine(DETA),tetraethylenepentamine(TEPA)andpentaethylenehexamine(PEHA))tostudytheeffectofaminechainlengthandloadingweightontheirCO2adsorptionperformancesindetail.TheadsorbentswerecharacterizedbyFT-IR,elementalanalysis,andthermo-gravimetricanalysistoconfirmtheirstructureproperties.Thermo-gravimetricanalysiswasalsousedtoevaluatetheCO2adsorptionperformanceofadsorbents.Longerchainamine-basedmaterialscanachievehigheramineloadingsandshowbetterthermalstability.TheCO2adsorptioncapacitiesatdifferenttemperaturesindicatethattheCO2adsorptionisthermodynamicallycontrolledoverEDAMCM41andDETA-MCM41,whiletheadsorptionoverTEPA-MCM41andPEHA-MCM41isunderkineticcontrolatlowtemperature.ThechainlengthofaminesaffectstheCO2adsorptionperformanceandtheadsorptionmechanismsignificantly.TheresultsalsoindicatethatCO2adsorptioncapacitycanbeenhanceddespiteofhighoperationtemperatures,ifappropriateamines(TEPAandPEHA)areapplied.However,adsorbentswithshortchainamineexhibithigheradsorptionanddesorptionratesduetothecollaborativeeffectofrapidreactionmechanismsofprimaryaminesandlessdiffusionresistanceofshorterchainlengthamines.

  • 标签: MCM-41 吸附性能 二氧化碳 胺基 材料 硅质
  • 简介:Fourkeyreactions,12C(,)13O,13C(,n)16O,25Mg(p,)26Aland19F(p,)16O,willbestudiedforthefirsttimewithinorneartheastrophysicalrelevantenergyregions(Gamowwindow)atJinpingUndergroundlaboratoryforNuclearAstrophysics(JUNA)[1],whichwilltaketheadvantageoftheultra-lowbackgroundofChinaJinPingundergroundLaboratory(CJPL),highcurrentacceleratorbasedonECRsourceandahighlysensitivedetectionsystem.

  • 标签: Institute MODERN PHYSICS
  • 简介:TheroleoftemperatureontheoxidationdynamicsofCu2OonZnO(0001)wasinvestigatedduringtheoxidationofCu(111)/ZnO(0001)byusingoxygenplasmaastheoxidant.AtransitionfromsinglecrystallineCu2O(111)orientationtomicro-zonephaseseparationwithmultipleorientationswasrevealedwhentheoxidationtemperatureincreasedabove300°C.TheexperimentalresultsclearlyshowtheeffectoftheoxidationtemperaturewiththeassistanceofoxygenplasmaonchangingthemorphologyofCu(111)filmandenhancingthelateralnucleationandmigrationabilitiesofcuprousoxides.Averticaltop-downoxidationmodeandalateralmigrationmodelwereproposedtoexplainthedifferentnucleationandgrowthdynamicsofthetemperature-dependentoxidationprocessintheoxidationofCu(111)/ZnO(0001).

  • 标签: CU2O OXIDATION plasma molecular BEAM EPITAXY
  • 简介:TheeffectsofTiO2onsinteringandnonlinearelectricalpropertiesof(98.5-x)ZnO–0.5MnO2–0.5Co2O3-0.5Bi2O3–xTiO2(x=0.3,0.5,0.7,0.9mol%)ceramicvaristorspreparedbytheceramictechniqueareinvestigatedinthiswork.Theoptimumsinteringtemperatureofthepreparedsamplesisdeducedbydeterminingthefiringshrinkageandwaterabsorptionpercentages.Theoptimumsinteringtemperatureisfoundtobe1200℃,atwhicheachofthesamplesshowsamaximumfiringshrinkageandminimumwaterabsorption.Alsominimumwaterabsorptionappearsinasampleofx=0.9mol%.HighersinteringtemperatureandlongersinteringtimegiverisetoareductioninbulkdensityduetotheincreasedamountofporositybetweenthelargegrainsofZnOresultingfromtherapidgraingrowthinducedbytheliquidphasesintering.ThecrystalsizeofZnOdecreaseswithincreasingTiO2doping.TheadditionofTiO2improvesthenonlinearcoefficientandattainsitsmaximumvalueatx=0.7mol%ofTiO2,furtheradditionnegativelyaffectsit.Adecreaseincapacitanceconsequentlyinthedielectricconstantisrecordedwithincreasingthefrequencyinarangeof30kHz–200kHz.ThetemperatureandcompositiondependencesofthedielectricconstantandACconductivityarealsostudied.Theincreaseoftemperatureraisesthedielectricconstantbecauseitincreasesionicresponsetothefieldatanyparticularfrequency.

  • 标签: ZNO压敏电阻 非线性系数 烧结温度 TIO2 介电性能 掺杂
  • 简介:采用TEA-CO2差分吸收激光雷达进行探测,是建立在气体组分对某些波长激光选择性吸收的基础上的,物质对波长的选择性吸收主要是由原子、分子内部能级的固有特性所决定的,进行探测时的技术难点在于种子源连续波导激光器频率稳定性的实现,也即是外差信号的高稳频技术,因为激光的频率稳定度将影响相干探测的混频效率,并在混频时产生相位噪声,降低系统的信噪比,直接影响探测灵敏度,因此激光雷达在信号发出到返回的时间内的频率稳定度是至关重要的。

  • 标签: 差分吸收激光雷达 光探测 选择性吸收 频率稳定度 实验 稳频技术
  • 简介:WereportontheoperationofpassivelyQ-switchedwaveguidelasersat1μmwavelengthbasedonagraphene∕WS2heterostructureasasaturableabsorber(SA).ThegainmediumisacrystallineNd:YVO4claddingwaveguideproducedbyfemtosecondlaserwriting.Thenanosecondwaveguidelaseroperationat1064nmhasbeenrealizedwiththemaximumaverageoutputpowerof275mWandslopeefficiencyof37%.IncomparisonwiththesystemsbasedonsingleWS2orgrapheneSA,thelasingQ-switchedbyagraphene∕WS2heterostructureSApossessesadvantagesofahigherpulseenergyandenhancedslopeefficiency,indicatingthepromisingapplicationsofvanderWaalsheterostructuresforultrafastphotonicdevices.

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  • 简介:PhotoelectrochemicalandelectrochemicalreductionofCO2intoorganicchemicalsispromisingfordirectlyorindirectlytransformingsolarenergyintochemicalenergyforfurtherutilization.However,researchontheelectroactivespeciesintheseprocesseshasbeenratherlimited.Inthiswork,weinvestigatedpossibleelectroactivespecies(CO2orHCO3–)involvedintheelectrochemicalreductionofKHCO3atelevatedtemperatureswithoutCO2bubbling.TheresultsshowedthatCO,CH4,andC2H4wereproducedafterelectrochemicalreductionof3.0mol/LKHCO3atelevatedtemperatureonaCuelectrodeevenwithoutCO2bubbling,althoughtheirfaradaicefficiencieswerelow(<6%).MeasurementsforCO2generationfromthedecompositionofHCO3–showedthatelevatedtemperatureandhighHCO3–concentrationstronglypromotedthisprocess.Theseresultssuggestedthatthein-situproducedCO2fromthedecompositionofHCO3–wasprobablytheelectroactivespeciesintheelectrochemicalreductionofHCO3–withoutCO2bubbling.ChangesoftheGibbsfreeenergy,rateconstant,andactivationenergyofthedecompositionofHCO3–intoCO2werealsoinvestigatedandcalculatedfromtheexperimentaldata.

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  • 简介:Two-dimensionalatomic-layeredmaterialisarecentresearchfocus,andsinglelayerTa2O5usedasgatedielectricinfield-effecttransistorsisobtainedviaassembliesofTa2O5nanosheets.However,theelectricalperformanceisseriouslyaffectedbyelectronicdefectsexistinginTa2O5.Therefore,spectroscopicellipsometryisusedtocalculatethetransitionenergiesandcorrespondingprobabilitiesfortwodifferentchargedoxygenvacancies,whoseexistenceisrevealedbyx-rayphotoelectronspectroscopyanalysis.SpectroscopicellipsometryfittingalsocalculatesthethicknessofsinglelayerTa2O5,exhibitinggoodagreementwithatomicforcemicroscopymeasurement.NondestructiveandnoncontactspectroscopicellipsometryisappropriatefordetectingtheelectricaldefectslevelofsinglelayerTa2O5.

  • 标签: TA2O5 电气性能 单层 缺陷 二维 电子能谱分析
  • 简介:Theregionaroundthedouble-closedshellnucleus208Pbhasbeenparticularlyusefulinstudyingresidualinteractions.ThelowspinisomersoftheisotopesintheN=127,Z=8387regionhavebeenidentifiedinlastfiftyyearsexcept213Rn[1??4].Inourrecentimplantation–r-acorrelationstudyoftheisotopesaroundtheN=126shellclosure,anewrayisobservedbetweentheimplantationsandthedecaysof213Rn,whichcouldbeduetothedepopulationoftheisomerof213Rnmentionedabove.

  • 标签: Implantation-r-a CORRELATION METHOD
  • 简介:近似所有人的癌症表演正常TP53基因表示的一半但是MDM2或MDMX的异常overexpression。这个事实建议有希望的癌症在指向在p53和MDM2/MDMX之间的相互作用的治疗学的策略。为了帮助,实现开发有效禁止者破坏p53-MDM2/MDMX相互作用的目标,我们系统地调查了结构并且有它和从用随机的分子的动力学模拟的一个原子论的观点的MDM2和MDMX的相互作用的禁止者的p53的相互作用特征。我们发现在MDM2和MDMX玩的结构的某特定的helices在他们的绑定给角色调音到禁止者,并且氢契约在MDM2或MDMX与它的对应物由p53的Trp23残余形成了,这在vivo从MDM2-p53建筑群决定MDM2-p53相互作用的混乱和p53的代替的动态比赛过程。结果在这报导纸被期望为设计功能的禁止者并且认识到癌症基因治疗的新策略提供基本信息。

  • 标签: MDM2 相互作用 竞争机制 结构效应 P53 肿瘤治疗
  • 简介:Ta2O5电影被常规电子横梁蒸发方法在熔化硅石底层上扔。由在不同温度退火,非结晶、六角形、斜方晶的阶段的Ta2O5电影被获得并且由X光证实衍射计(XRD)结果。X光检查光电子光谱学(XPS)分析证明所有这些电影的化学作文是stoichiometry。非结晶的Ta2O5电影完成最高的激光,这被发现在355或1064nm的导致的损坏阀值(LIDT)任何一个,由六角形的阶段和最后斜方晶的阶段列在后面。当前者显示出一个一致熔化区域,当后者在至少一个缺点点上被集中时,在355和1064nm的损坏形态学是不同的,它被不同损坏机制导致。在1064nm的LIDT的减少被归因于增加结构的缺点,当时在355nm由于增加的联合效果结构的缺点和减少的乐队差距精力。[从作者抽象]

  • 标签: 氧化钽薄膜 激光损坏阈 电子束放射法 相结构
  • 简介:TheLHCDantennathatwillbeusedinHL-2AistheoriginaloneusedinHL-1M,whichwillbemodified.Wemeasuredthefeatureoftheantenna.Thefeaturesincludethereflectionofmainwaveguide,VSWR,theadjacentphrasingbetweenthesub-waveguidesandsoon.Thepaperdescribesthemeasuredresultsandspectrumcalculationbasedonthemeasuredparameters.FromtheworkswecanappreciateourantennacorrectlywhichwillbeusefulforLHCDexperimentonHL-2Aintheyear.

  • 标签: HL-2A LHCD 子波导 多节发射天线阵 波谱 数值计算
  • 简介:ThisworkismainlytostudytheeffectofheavyionirradiationonthedamageofsinglelayerMoS2.ThenumberoflayersofMoS2preparedbyCVD(chemicalvapordeposition)methodwasdeterminedbyopticalmicroscopyandRamanspectroscopy.ThemonolayerMoS2preparedbyCVDunderhighenergy209BiionirradiationwasanalyzedbyRamananalysisandAFMobservation.AndtheresultsarecomparedandanalyzedbeforeandafterthebeamirradiationofsinglelayerMoS2preparedbymechanicalstrippingmethod.

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  • 简介:Weproposeandexperimentallydemonstratecompacton-chip1×2wavelengthselectiveswitches(WSSs)basedonsiliconmicroringresonators(MRRs)withnestedpairsofsubrings(NPSs).OwingtotheresonancesplittinginducedbytheinnerNPSs,theproposeddevicesarecapableofperformingselectivechannelroutingatcertainresonancewavelengthsoftheouterMRRs.SystemdemonstrationofdynamicchannelroutingusingfabricateddeviceswithoneandtwoNPSsiscarriedoutfor10Gb∕snon-return-to-zerosignal.Theexperimentalresultsverifytheeffectivenessofthefabricateddevicesascompacton-chipWSSs.

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  • 简介:为实现2×5GW级双路输出超宽谱高功率微波驱动源的小型化,研制了一种初级脉冲功率源——与双筒脉冲形成线(Blumlein线)相配一体化的带有开路磁芯的Tesla变压器.通过对Tesla变压器的理论分析,并根据简化的磁路模型得出了Tesla变压器初、次级线圈电感等电参数的估算方法,给出了Tesla变压器磁芯截面的估算和磁芯制作方法.实验结果表明,Tesla变压器最大输出电压为880kV,充电时间约为20μts,耦合系数约为0.95,与理论值吻合较好.

  • 标签: TESLA变压器 初级线圈 次级线圈 开路磁芯