简介：有机-无机杂化复合纳米材料可以在微观尺寸上将有机和无机组分相结合,使复合材料兼具两种组分的优点,实现所需的性能或功能,因此成为材料学的研究热点之一。本文以有机荧光染料罗丹明、三苯胺和金属配合物发光材料为母体,制备出一系列对汞离子、铜离子、铁离子等常见金属离子具有明显光谱响应的探针类材料并选取合适的支撑基质组装成有机-无机复合材料,实现了对金属离子和一些阴离子的目视比色传感。不同离子的加入及加入顺序都会对探针类材料的吸收及发光光谱造成明显的变化。以不同的金属离子或氧气作为输入值,以吸收强度/发光强度作为输出值,模拟了分子水平的逻辑门,拓展了这些材料的应用。为了解决背景荧光干扰,我们利用六角相的β-NaYF4纳米晶为激发源,采用二氧化硅进行包覆,然后将荧光探针分子固载到二氧化硅表面,得到了对金属离子具有传感性能的核壳型的上转换纳米复合材料。在近红外激发下能够显示明亮的上转换绿光发射,同时对金属离子具有较好的选择性、较高的灵敏度,并且其荧光强度表现出对汞离子浓度的线性响应。这种纳米复合材料的上转换光学性质、汞离子传感性能使它们在分析化学、生物化学等领域有潜在的应用价值。

简介：PureAl2O3-2SiO2powderswerepreparedbysol-gelandcoprecipitationmethods,andtheiralkaliactivationreactivitieswerecompared.Thealkali-activationreactivityofthepowderpreparedbythesol-gelmethodwashigherthanthatofthepowderpreparedbythecoprecipitationmethod.Thepowderswereinvestigatedby27AIand29Simagic-anglespinningnuclearmagneticresonancespectroscopy（MASNMR）tounderstandtherelationshipbetweentheirstructureandalkali-activationreactivity.The27AlMASNMRdatashowedthatthefive-coordinateAIcontentofthepowderpreparedbythesol-gelmethodwashigherthanthatofthepowderpreparedbycoprecipitation.Thehighercontentoffive-coordinateAlcorrespondedtohigheralkali-activationreactivity.The29SiMASNMRdatashowedthatforthepowderpreparedbythesol-gelmethod,siliconwasreplacedbyaluminumatsecondarycoordinationsitesofthecentralSiatomsduringcalcination.However,forthepowderpreparedbysingle-batchcoprecipitation,themainchangewasfromalowdegreeofpolycondensationtoahighdegreeofpolycondensation.

简介：Moleculardynamics(MD)simulationswereperformedtostretchtherectangulargraphenesheetsdopedwithsilicon,nitrogenorboronatoms.Young’smodulus,ultimatestress(strain)andenergyabsorptionweremeasuredforthegraphenesheetswiththedopingconcentration(DC)rangingfrom0to5%.Theemphasiswasplacedonthedistincteffectsofeachindividualdopantonthefundamentalmechanicalpropertiesofgraphene.TheresultsindicatedthatincorporatingthedopantsintographeneledtoanalmostlineardecreaseinYoung’smodulus.Monotonicreductionsinultimatestrength,ultimatestrainandenergyabsorptionwerealsoobserved.Suchdopingeffectswerefoundtobemostsignificantforsilicon,lesspronouncedforboron,andsmallornegligiblefornitrogen.Theoutputsprovideanimportantguidanceforthedevelopmentandoptimizationofnovelnanoscaledevices,andfacilitatethedevelopmentofgraphene-basedM/NEMS.

简介：Li4Ti5O12（LTO）/carbonnanotubes（CNTs）compositematerialissynthesizedbasedonasolid-statemethodbysand-milling,spray-dryingandcalciningat8508CunderN2flow.TheLTO/CNTssampleswith1wt%and3wt%weightratioofCNTsadditionandthepristineLTOsampleareprepared.TherateperformanceandthethermalstabilityofthesesamplesareinvestigatedbasedonLiMn2O4（LMO）/LTOfull-cell.TheresultsshowthattheweightratioofCNTsadditionhasdistincteffectonLTOperformances.ThecompositematerialsofLTOcompositedCNTshavebetterperformanceathigh-rateduetotheintercalationenhancementbyconductivenetworkofCNTs.Atsecond,theoverchargingtemperatureresponseofthecell’ssurfacewith1wt%CNTsadditionisthelowest.Theparticlesizedistributionismeasuredandthemostuniformparticlesareobtainedwith1wt%CNTsaddition.ThistrendcouldexplainthatthemediumquantityofCNTsisoptimaltoimprovetheheatandmasstransferandpreventtheproblemsofcrystallitegrowinginterferenceandaggregationduringthecalcinationprocess.

简介：在同一直线上的双脉搏的导致激光的故障光谱学被使用一双毫微秒Nd在Si水晶上执行:在1064nm射出的钇铝柘榴石激光来源。光谱紧张和选择Si原子、离子的线的signalto-噪音比率被用来评估光排放。当改变interpulse延期时间和二的精力比率时，光排放紧张被记录搏动的激光。线紧张和signal-to-noise比率上的数据获得延期时间的效果也被调查了。基于结果，最佳的interpulse延期时间，二的精力比率搏动了激光，和完成原子、离子的最大值的数据获得延期时间衬里紧张被作出对有利的裁决有在同一直线上的双脉搏的激光途径的Si血浆的产生。为观察的线紧张变化的主导的机制也被讨论。另外，在不同的门的血浆温度和电子数字密度推迟时间和不同interpulse延期时间被导出。血浆在更短的interpulse延期时间在电子温度和电子数字密度上防护的重要影响被观察。

简介：Onenewsesquiterpenecompound,namely,illihenlactoneA（1）,andonenewprenylatedC6–C3compound,illihenryioneH（2）,alongwiththreeknownsesquiterpenes（3–5）wereisolatedfromthestemsofIlliciumhenryi.Thestructuresof1and2wereelucidatedbyspectroscopicevidenceincludingNMR,HRESIMSandcirculardichroism（CD）.Compound2exhibitedaweakinhibitoryratioforbglucuronidasereleaseinducedbyplatelet-activatingfactor（PAF）inratpolymorphonuclearleukocytes（PMNs）invitro.

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.

简介：Inthispaper,weintroduceaconditionweakerthantheLpdifferentiability,whichwecallCpcondition.Weprovethatifafunctionsatisfiesthisconditionatapoint,thenthereexiststhebestlocalapproximationatthatpoint.WealsogiveanecessaryandsufficientconditionforthatafunctionbeLpdifferentiable.Inaddition,westudytheconvexityofthesetofclusterpointsofthenetofbestappoximationsoff,{Pe(f)}ase→0.

简介：Inthispaper,weapplythecontractionmappingtheoremtoestablishsomeboundedandunboundedadditiveperturbationtheoremsconcerninglocalC-semigroups.SomegrowthconditionsofperturbationsoflocalC-semigroupsarealsoestablished.

简介：ThefirststarsintheearlyUniversewereformedabout400millionyearsafterthebigbang.VerificationoftheexistenceofthesestarsisimportantforourunderstandingoftheevolutionoftheUniverse[1].IthasbeenpredictedthatforPopulation-IIIstellarproductionyields,theabundancesofodd-Zelementsareremarkablydeficientcomparedtotheiradjacenteven-Zelements[2].Astronomersaresearchingforlong-lived,lowmassstarswiththeuniquenucleosyntheticpatternmatchingthepredictedyields[3].

简介：

简介：

简介：Si-richsiliconnitridefilmsarepreparedbyplasma-enhancedchemicalvapordepositionmethod,followedbythermalannealingtoformtheSinanocrystals(Si-NCs)embeddedinSiNxfloatinggateMOSstructures.Thecapacitance–voltage(C–V),current–voltage(I–V),andadmittance–voltage(G–V)measurementsareusedtoinvestigatethechargingcharacteristics.Itisfoundthatthemaximumflatbandvoltageshift(△VFB)duetofullchargedholes(～6.2V)ismuchlargerthanthatduetofullchargedelectrons(～1V).ThechargingdisplacementcurrentpeaksofelectronsandholescanbealsoobservedbytheI–Vmeasurements,respectively.FromtheG–VmeasurementswefindthattheholeinjectionisinfluencedbytheoxideholetrapswhicharelocatedneartheSiO2/Si-substrateinterface.CombiningtheresultsofC–VandG–Vmeasurements,wefindthattheholechargingoftheSi-NCsoccursviaatwo-steptunnelingmechanism.TheevolutionofG–VpeakoriginatedfromoxidetrapsexhibitstheprocessofholeinjectionintothesedefectsandtransferringtotheSi-NCs.

简介：利用YAG-50型声光调Q激光划片机对156＋156＊0．18mm的多晶硅太阳能电池片进行划片实验，得到了不同调Q频率和电池片电性能参数的关系，从而找出了Q开关的最佳频率范围值，并从理论上探讨分析了不同调Q频率范围划片得到的太阳能电池片电性能参数差异的原因。

简介：用单辊甩带法制备了不含高生物毒性元素的Ti60Zr10Ta15Si15非晶薄带,并在高于其晶化开始温度的不同温度下对该非晶薄带进行了真空退火,研究了该非晶薄带在磷酸盐缓冲溶液（PBS）中的电化学腐蚀行为及热处理对其显微组织及其电化学行为的影响。结果表明,用单辊甩带法制备的Ti60Zr10Ta15Si15金属薄带为完全的非晶态结构,其玻璃转变温度和晶化开始温度分别为759K和833K,经过878K真空热处理后,薄带发生了部分晶化,在非晶的基底上析出了Ti相;经过938K热处理后,薄带发生了完全晶化,晶化相主要由Ti、Si3Ta5和SiZr以及TiSi组成。动电位极化测试表明,该非晶合金在PBS溶液中可表现出较为优异的耐蚀性能,部分晶化可进一步提高该合金的耐蚀性能,而完全晶化的合金抗腐蚀性能明显下降。

简介：CO2methanationhasbeenahottopicbecauseofitsimportantapplicationinthespacecraftandpotentialutilizationofcarbondioxide.Nickelcatalystisactiveforthisreaction.However,itsactivitystillneedstobeimproved.Dielectricbarrierdischarge(DBD)plasma,initiatedatambientconditionandoperatedat~150°C,hasbeenemployedinthisworkfordecompositionofnickelprecursortoprepareNi/MgAl2O4.Theplasmadecompositionresultsinhighdispersion,uniquestructure,enhancedreducibilityofNiparticlesandpromotedcatalyst-supportinteraction.AnimprovedactivityofCO2methanationwithahigheryieldofmethanehasbeenachievedovertheplasmadecomposedcatalyst,comparedtothecatalystpreparedthermally.Forexample,themethaneyieldoftheplasmapreparedcatalystis71.8%at300°Cbutitis62.9%overthethermalpreparedcatalyst.ThecatalystcharacterizationconfirmedthatCO2methanationovertheDBDplasmapreparedcatalystfollowspathwayofCOmethanation.

简介：

简介：Inthisarticle,nano-scaleAl/Fe2O3compositeswithdifferentmorphologiesweresuccessfullyobtainedbyasimpleelectrospinningtechnique,whichisbasedonasurfactant（polyvinylpyridine,PVP）inamixtureofN,N-dimethylformamide（DMF）and2-propanol.TheelectrospunAl/Fe2O3compositesexhibitedacrystalstructureandphasecompositionbyX-raydiffractionanalysis.ThedifferentmorphologiesoftheAl/Fe2O3compositeswerealsoobservedthroughscanningelectronmicroscopyandtransmissionelectronmicroscopy.Itwasfoundthattherathersimpleelectrospinningmethodusedtopreparethemorphology-controlledAl/Fe2O3compositesmayhavethepotentialforpreparationofpropellants,explosives,andpyrotechnicsinthefuture.

简介：TheeffectofacidcomponentincludingvariousconventionalacidsandtungsticcompoundsonglucosehydrogenationoveraseriesofbinarycatalystsystemcontainingRu/Ccatalystwasinvestigated.TheresultsshowedthatHCl,H2SO4,H3BO3,H3PO4,andHNO3hadnegligibleeffect,whileallthetungsticcompoundsimposedinhibitingeffectsonthehydrogenationofglucoseoverRu/Ccatalyst,andthesuppressingeffectfollowedtheorderofH2WO4>HPW>WO3>AMT>HSiW.Thisorderisthesameastheorderofethyleneglycol(EG)yieldsintheone-potconversionofglucosetoEG,suggestingtheimportantroleofcompetitionbetweenglucosehydrogenationandretro-aldolcondensationincontrollingtheselectivityofEG.

简介：