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25 个结果
  • 简介:ThecapacitytocaptureCO2wasdeterminedinseveralstoichiometriccompositionsintheLi2O–Bi2O3system.Thecompounds(Li7BiO6,Li5BiO5,Li3BiO4andLiBiO2phases)weresynthesizedviasolid-statereactionandcharacterizedbyX-raydiffraction,scanningelectronmicroscopyandN2adsorptiontechniques.Thesampleswereheat-treatedattemperaturesfrom40to750°CundertheCO2atmospheretoevaluatethecarbonateformation,whichisindicativeofthecapacityofCO2capture.Moreover,Li7BiO6showsanexcellentCO2capturecapacityof7.1mmol/g,whichisconsiderablyhigherthanthoseofotherpreviouslyreportedceramics.Li7BiO6isabletoreactwithCO2from240°Ctoapproximately660°CshowingahighkineticreactionevenatCO2partialpressurevaluesaslowas0.05.

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  • 简介:对化合物[Na_2(H_2O)_(10)][Cu_4(H_2O)_(12)(H_2W_(12)O_(42))]·15H_2O(简称Na_2Cu_4W_(12))进行了体外抗肿瘤活性研究.应用四甲基偶氮唑盐(3-[4,5-dimethylthiazo-2-y]-2,5-diphenyltetrazoliumbromide,MTT)比色法分析Na_2Cu_4W_(12)对人肝癌细胞(HepG2)、人神经母细胞瘤细胞(SHY5Y)增殖抑制活性.采用光学显微镜观察肿瘤细胞的凋亡形态变化,用流式细胞术分析细胞周期和细胞凋亡,计算各期细胞比例及细胞凋亡率.结果表明,Na_2Cu_4W_(12)对HepG2和SHY5Y2种肿瘤细胞增殖半数抑制浓度IC_(50)值分别为5.3和10.2μmol·L~(-1),且呈剂量依赖性.光学显微镜下处理组细胞出现皱缩、变圆、缩小等形态变化,不同浓度Na_2Cu_4W_(12)处理12h早期凋亡细胞所占的百分比显著增加且呈剂量依赖性.综上所述,Na_2Cu_4W_(12)能够抑制胞瘤细胞增殖,诱导细胞凋亡.

  • 标签: 仲钨酸盐化合物 抗肿瘤 体外研究
  • 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:磁铁矿(Fe3有不同尺寸和形状的O4)nanoparticles被热分解方法综合。二条途径,非注射一个壶和热注射的方法,被设计详细调查生长机制。nanoparticles的尺寸和形状被调整先锋集中和持续时间时间决定,这被发现,它能好在我们的合成系统基于LaMer模型由机制解释了。monodisperseFe3O4nanoparticles从5nm有一条吝啬的直径到16nm,和形状进化从对球形三角形、立方。磁性是尺寸依赖者,和Fe3在关于在房间温度和最大的浸透磁化的5nm展览superparamagnetic性质的小尺寸的O4nanoparticles来临到78emu/g,而Fe3O4nanoparticles当直径增加到大约16nm时,开发铁磁性的性质。

  • 标签: 纳米FE3O4 磁性纳米粒子 合成系统 单分散 FE3O4纳米粒子 可控
  • 简介:AnefficientprocessfortheconversionofdimethyloxalateintoethyleneglycolwithhighselectivityandhighyieldoverCu2Owasinvestigated.InsituformedCuasatruecatalyticallyactivespeciesshowedagoodcatalyticperformanceforDMOconversiontoproduceEGin95%yield.

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  • 简介:Twofamiliesofcatalysts,basedonPdnanoparticlessupportedonceramicasymmetrictubularaluminamembranes,arestudiesinthedirectsynthesisofH_2O_2.TheyarepreparedbydepositingPdintwoways:(i)reductionwithN_2H_4inanultrasonicbathand(ii)byimpregnation-deposition.Thefirstpreparationleadstolargerparticles,withaveragesizeofaround11nm,whilethesecondpreparationleadstosmallerparticles,withaveragesizearound4nm.Thecatalyticmembranesweretestedasprepared,afterthermaltreatmentinairandafterfurtherpre-reductionwithH_2inmild(100℃)conditions.SampleswerecharacterizedbyTEM,CO-chemisorptionmonitoredbyDRIFTSmethodandTPR,whilecatalytictestshavebeenperformedinasemi-batchrecirculationmembranereactor.Experimentalcatalyticresultswereanalysedusingtwokineticsmodelstoderivethereactionconstantsfortheparallelandconsecutivereactionsofthekineticnetwork.SmallerparticlesofPdshowlowerselectivityduetothehigherrateofparallelcombustion,evenifthebetterdispersionofPdandthushighermetalsurfaceareainthesampleleadtoaproductivityinH_2O_2similarorevenhigherthanthesamplewiththelargerPdparticles.IndependentlyonthepresenceofsmallerorlargerPdnanoparticles,anoxidationtreatmentleadstoasignificantenhancementintheproductivity,althoughthecatalystprogressivelyreducesduringthecatalyticprocess.Theinhibitionoftheparallelcombustionreaction(towater)inducedfromthecalcinationtreatmentremainsafterthein-situreductionoftheoxidizedPdspeciesformedduringthepre-treatment.Thisislikelyduetotheeliminationofdefectsiteswhichdissociativelyactivateoxygen,andtentativelyattributedtoPdsitesabletogivethree-andfour-foldcoordinationofCO.

  • 标签: 钯纳米粒子 过氧化氢 直接合成 预处理 TEM样品 动力学模型
  • 简介:Cu2ZnSnS4(CZTS)基于太阳能电池被microelectronic和photonic结构(AMPS-1D)的一个维的太阳能电池模拟软件分析数字地模仿。在模拟使用的设备结构是Al/ZnO:Al/nZn(O,S)/pCZTS/Mo。工作是在ZnO1xSx缓冲区层,它将产出更高的变换效率。由改变S/(S+O)比率x,在CZTS/Zn的传导乐队偏移量(CBO)(O,S)如果比率的完整的范围被考虑,接口能从0.23eV到1.06eV。当时,0.23eV的最佳的CBO能被完成ZnO1xSx缓冲区有S/(S+O)0.6的比率。太阳能电池效率首先与增加硫内容增加然后为x突然地减少>0.6,它由我们的建议的最佳的硫内容x=到达17.55%的最高的价值0.6。我们的结果在处理ZnO1x为高效率CZTS的Sx缓冲区层免职太阳能电池。

  • 标签: Zn(O S) CZTS太阳能电池 性能 放大器缓冲层
  • 简介:Multilayerblackphosphorus(BP)nanoplateletsofdifferentthicknesseswerepreparedbytheliquidphaseexfoliationmethodanddepositedontoyttriumaluminumgarnetsubstratestoformsaturableabsorbers(SAs).Thesewerecharacterizedwithrespecttotheirthickness-dependentsaturableabsorptionpropertiesat3μm.TheBP-SAswereemployedinapassivelyQ-switchedEr:Lu2O3laserat2.84μm.ByusingBPexfoliatedindifferentsolvents,stablepulsesasshortas359nsweregeneratedatanaverageoutputpowerofupto755mW.Therepetitionrateintheexperimentwas107kHz,correspondingtoapulseenergyof7.1μJ.TheseresultsprovethatBP-SAshaveagreatpotentialforopticalmodulationinthemid-infraredrange.

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  • 简介:Ithasbeenproposedthatfusionreactionsbetweenneutron-richlightnuclei,forexample24C,24Oand28Ne,maycontributetoachievingtheignitiontemperatureforexplosivecarbonburningprocessduringsuperbusrsts[1,2].Studiesoffusionreactionsinvolvingneutron-richnucleiarebeyondordinaryexperimentaltechniques,sincetheintensityofradioactivebeambecomelowforthesemeasurements[3].TheactivetargettechniqueusingTPC(TimeProjectionChamber),withpropertiesofmulti-sampling,highefficiencyandlowbackground,isasuitablesolutiontotheproblem.

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  • 简介:ThepresolarSiCgrains[1]carrytheoriginalstellarnucleosynthesissignature.Theirisotopicanomaliescomparedtothesunarethestrongconstrainsinthesupernovae(SN)modelcalculations.The15N-excessinsomeSiC-ABgrains(12C/13C<10and14N/15N<272)isoneofthechallengesofcore-collapsesupernovae(CCSNe)models[2].Recently,PignataripointedoutthattheentrainmentofH-richmaterialintotheHeshellbeforetheSNexplosionallowsthecoproductionof13C,15Nand26Al,whichprovidesanewproductionscenarioforSiC-ABgrains[2].IntheHeshellnucleosynthesis,the13Cisproducedthrough12C(p,γ)13N(β+γ)13Creaction.The14Nissynthesizedthrough13N(n,γ)and13C(p,γ)reactions.

  • 标签: EXPERIMENTAL STRONG SIC SUN 15N He
  • 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:介绍了阻变存储器及其I-V特性的测试分析方法。通过测量三明治结构的阻变存储器的I-V特性,采用多种拟合方法,与导电机制原理对比,可以判断器件的导电机制,便于深入分析阻变机理。

  • 标签: 电致阻变 I-V特性 导电机制
  • 简介:Inthisstudy,nanocrystallineCo–Ni–MgferritepowderswithcompositionCo0.5Ni0.5-xMgxFe2O4aresuccessfullysynthesizedbytheco-precipitationmethod.Asystematicinvestigationonthestructural,morphologicalandmagneticpropertiesofun-dopedandMg-dopedCo–Niferritenanoparticlesiscarriedout.Thepreparedsamplesarecharacterizedusingx-raydiffraction(XRD)analysis,Fouriertransforminfraredspectroscopy(FTIR),fieldemissionscanningelectronmicroscopy(FESEM),andvibratingsamplemagnetometry(VSM).TheXRDanalysesofthesynthesizedsamplesconfirmtheformationofsingle-phasecubicspinelstructureswithcrystallitesizesinarangeof32nmto36nm.ThelatticeconstantincreaseswithincreasingMgcontent.FESEMimagesshowthatthesynthesizedsamplesarehomogeneouswithauniformlydistributedgrain.TheresultsofIRspectroscopyanalysisindicatetheformationoffunctionalgroupsofspinelferriteintheco-precipitationprocess.ByincreasingMg2+substitution,roomtemperaturemagneticmeasurementshowsthatmaximummagnetizationandcoercivityincreasefrom57.35emu/gto61.49emu/gand603.26Oeto684.11Oe(1Oe=79.5775A·m-1),respectively.ThehighervaluesofmagnetizationMsandMrsuggestthattheoptimumcompositionisCo0.5Ni0.4Mg0.1Fe2O4thatcanbeappliedtohigh-densityrecordingmediaandmicrowavedevices.

  • 标签: 尖晶石铁氧体 尖晶石结构 纳米晶 磁性能 镁掺杂 振动样品磁强计
  • 简介:Fe_(3–x)O_4raspberryshapednanostructures/graphenenanocompositesweresynthesizedbyaone-steppolyol-solvothermalmethodtobetestedaselectrodematerialsforLi-ionbattery(LIB).Indeed,Fe_(3–x)O_4raspberryshapednanostructuresconsistoforiginalorientedaggregatesofFe_(3–x)O_4magnetitenanocrystals,ensuringalowoxidationstateofmagnetiteandahollowandporousstructure,whichhasbeeneasilycombinedwithgraphenesheets.TheresultingnanocompositepowderdisplaysaveryhomogeneousspatialdistributionofFe_(3–x)O_4nanostructuresatthesurfaceofthegraphenesheets.TheseoriginalnanostructuresandtheirstronginteractionwiththegraphenesheetsresultedinverysmallcapacityfadinguponLi+ionintercalation.Reversiblecapacity,ashighas660mAh/g,makesthismaterialpromisingforanodeinLi-ionbatteriesapplication.

  • 标签: 纳米复合材料 锂离子电池 覆盆子 石墨 FE 性能
  • 简介:采用CBS-QB3方法构建了丙烯酸甲酯(CH_2=CHCOOCH_3)与O_3反应体系的势能剖面并在此基础上利用经典过渡态理论(TST)和Wigner矫正模型计算了标题反应在200K~1200K温度区间内的速率常数kTST/W.研究结果表明,CH_2=CHCOOCH)3与O)3反应首先经过渡态生成一个稳定的五元环中间体,然后按断键位置不同,分别生成产物P1(CH_3OCOCHO+CH_2O_2)和P2(CH)3OCOCHOO+HCHO).此外,速率常数结果显示,在计算温度范围内,标题反应速率常数呈正温度系数效应.294K时,CH_2=CHCOOCH_3与O_3反应速率常数为1.76×10^(-18)cm^3·molecule^(-1)·s^(-1),与所测实验值(0.95±0.07)×10^(-18)cm^3·molecule^(-1)·s^(-1)非常接近.

  • 标签: CH2=CHCOOCH3 O3 Criegee机理 反应机理 速率常数
  • 简介:采用一步法合成了氨基化四氧化三铁(NH2-Fe3O4)磁性纳米材料,并以XRD,IR等手段对其进行了表征.将NH2-Fe3O4组装到磁性玻碳电极表面,得了NH2-Fe3O4修饰的磁玻碳电极,并以该修饰电极为工作电极,研究了其电化学性能.利用差分脉冲溶出伏安法研究了铅(Ⅱ)离子和铜(Ⅱ)离子在该修饰电极上的电化学行为.结果表明:NH2-Fe3O4纳米粒子可显著提高Pb2+和Cu2+在电极表面的富集量,提高溶出峰电流.由于差分脉冲溶出伏安曲线中Pb2+和Cu2+的溶出峰电位差较大,且没有相互干扰,所以该电极可用于Pb2+和Cu2+的同时测定.

  • 标签: 氨基化Fe3O4 磁性玻碳电极 PB2+ Cu2+
  • 简介:TypeIX-rayburstsarethemostfrequentthermonuclearexplosionsinnature,resultingfromthermonuclearrunawayonthesurfaceofanaccretingneutronstar[1].Thebreakoutreaction14O(α ,p)17FfromthehotCNOcyclemayhaveaprominentimpactontheburstlightcurveandburstashes[2].However,insufficientexperimentalinformationisavailabletocalculateareliable,preciserateforthisreaction[3].Weproposedtoaddresstheexperimentalinvestigationofthe14O(α,p)17FusingTimeProjectionChamber(TPC)[4].

  • 标签: PROJECTION SIMULATION GEANT4 experimental surface impact
  • 简介:通过Cu纳米颗粒掺杂制备了Li[(Ni0.6Co0.2Mn0.2)1-xCux]O2三元正极材料,并通过调节Cu的掺杂量,讨论了Cu的掺入对Li[(Ni0.6Co0.2Mn0.2)1-xCux]O2三元正极材料晶体结构、表面形貌、电化学性能和循环性能等一系列性能的影响,铜掺杂量为x=0.01时,在0.2C倍率下的首次放电比容量达到了219.1mAh/g,经过50次充放电循环之后,剩余比容量为115.4mAh/g。最终结果为Li[(Ni0.6Co0.2Mn0.2)1-xCux]O2中Cu的掺入量为x=0.01时,所得正极材料的电化学性能和循环性能最为优异。

  • 标签: 锂离子电池 三元正极材料 纳米Cu掺杂 电化学性能 循环性能
  • 简介:以4-[(8-羟基-5-喹啉)偶氮]-苯磺酸与氯化钴为原料,采用溶剂热法通过原位反应合成{[Co(5-氨基-8-羟基喹啉)_2]·H_2O}_n,并通过X-射线单晶衍射方法确定了该配合物的晶体结构.结构分析表明:标题配合物属于斜方晶系,Pbcn空间群,晶胞参数a=1.321(2)nm,b=0.811(2)nm,c=1.511(2)nm,α=β=γ=90.00°,V=1.619(3)nm~3,Z=4,R_1=0.0516,wR_2=0.1025.配合物中存在ππ堆积相互作用和氢键作用,将配合物连接形成三维超分子网络结构.

  • 标签: Co(Ⅱ)配合物 氢键 π…π堆积 超分子
  • 简介:AnewlayeredCu-basedoxychalcogenideBa3Fe2O5Cu2S2hasbeensynthesizedanditsmagneticandelectronicpropertieswererevealed.Ba3Fe2O5Cu2S2isbuiltupbyalternativelystacking[Cu2S2]2-layersandironperovskiteoxide[(FeO2)(BaO)(FeO2)]2-layersalongthecaxisthatareseparatedbybariumionswithFe3+fivefoldcoordinatedbyasquare-pyramidalarrangementofoxygen.Fromthebondvalencearguments,weinferredthatinlayeredCuCh-based(Ch=S,Se,Te)compoundsthe+3cationinperovskiteoxidesheetprefersasquarepyramidalsite,whilethelowervalencecationprefersthesquareplanarsites.Thestudiesonsusceptibility,transport,andopticalreflectivityindicatethatBa3Fe2O5Cu2S2isanantiferromagneticsemiconductorwithaNe′eltemperatureof121Kandanopticalbandgapof1.03eV.Themeasurementofheatcapacityfrom10Ktoroomtemperatureshowsnoanomalyat121K.TheDebyetemperatureisdeterminedtobe113K.TheoreticalcalculationsindicatethattheconductionbandminimumispredominantlycontributedbyO2pand3dstatesofFeionsthatantiferromagneticallyarrangedinFeO2layers.TheFe3dstatesarelocatedatlowerenergyandresultinanarrowbandgapincomparisonwiththatoftheisostructuralSr3Sc2O5Cu2S2.

  • 标签: 钙钛矿型氧化物 铁磁半导体 光学带隙 德拜温度 电子性质 阳离子