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简介：ThecorrelationbetweenphasestructuresandsurfaceacidityofAl2O3supportscalcinedatdifferenttemperaturesandthecatalyticperformanceofNi/Al2O3catalystsintheproductionofsyntheticnaturalgas(SNG)viaCOmethanationwassystematicallyinvestigated.Aseriesof10wt%NiO/Al2O3catalystswerepreparedbytheconventionalimpregnationmethod,andthephasestructuresandsurfaceacidityofAl2O3supportswereadjustedbycalciningthecommercialγ-Al2O3atdifferenttemperatures(600–1200C).COmethanationreactionwascarriedoutinthetemperaturerangeof300–600Catdifferentweighthourlyspacevelocities(WHSV=30000and120000mL·g-1h-1)andpressures(0.1and3.0MPa).ItwasfoundthathighcalcinationtemperaturenotonlyledtothegrowthinNiparticlesize,butalsoweakenedtheinteractionbetweenNinanoparticlesandAl2O3supportsduetotherapiddecreaseofthespecificsurfaceareaandacidityofAl2O3supports.Interestingly,NicatalystssupportedonAl2O3calcinedat1200C(Ni/Al2O3-1200)exhibitedthebestcatalyticactivityforCOmethanationunderdifferentreactionconditions.LifetimereactiontestsalsoindicatedthatNi/Al2O3-1200wasthemostactiveandstablecatalystcomparedwiththeotherthreecatalysts,whosesupportswerecalcinedatlowertemperatures(600,800and1000C).ThesefindingswouldthereforebehelpfultodevelopNi/Al2O3methanationcatalystforSNGproduction.

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简介：Inthiswork,syngasmethanationoverNi-W/TiO2-SiO2catalystwasstudiedinafluidized-bedreactor(FBR)anditsperformancewascomparedwithafixed-bedreactor(FIXBR).Theeffectsofmainoperatingvariablesincludingfeedstockgasesspacevelocity,cokecontent,bedtemperatureandsulfur-tolerantstabilityof100hlifewereinvestigated.ThestructureofthecatalystswascharacterizedbyXRD,N2adsorptiondesorptionandTEM.Itisfoundthatundersamespacevelocityfrom5000h1to25000h1FBRgaveahigherCH4yield,lowercokecontent,andlowerbedtemperaturethanthoseobtainedinFIXBR.Ni-W/TiO2-SiO2catalystpossessedexcellentsulfur-tolerantstabilityonthefeedstockgaseslessthan500ppmH2SinFBR.ThecarbondepositsformedonthespentcatalystwereintheformofcarbonfibersinFBR,whileintheformofdenseaccumulationdistributionappearanceinFIXBR.

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简介：HydrotalciteprecursorsofLamodifiedNi-Al2O3andNi-SiO2catalystspreparedbyco-precipitationmethodandthecatalyticactivitieswereexaminedfortheproductionofCOx-freeH2byCH4decomposition.Physico-chemicalcharacteristicsoffresh,reducedandusedcatalystswereevaluatedbyXRD,TPRandO2pulsechemisorptions,TEMandBET-SAtechniques.XRDstudiesshowedphasesduetohydrotalcite-likeprecursorsinovendriedformproduceddispersedNiOspeciesuponcalcinationinstaticairabove450C.Ramanspectraofdeactivatedsamplesrevealedthepresenceofbothorderedanddisorderedformsofcarbon.Ni-La-Al2O3catalystwithamoleratioofNi:La:Al=2:0.1:0.9exhibitedtremendouslyhighlongevitywithahydrogenproductionrateof1300molH2mol1Ni.AdirectrelationshipbetweenNimetalsurfaceareaandhydrogenyieldswasestablished.

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简介：测量了ZnO-TiO2-Bi2O3-CuO-Co2O3,ZnO-TiO2-Bi2O3-CuO-Cr2O3,ZnO-TiO2-Bi2O3-CuO-MnO2和ZnOTiO2-Bi2O3-CuO-MnO2-Co2O3-Cr2O3压敏陶瓷的正电子寿命谱及其电性能参数。研究了MnO2、Co2O3和Cr2O3掺杂对ZnO-TiO2-Bi2O3-CuO压敏陶瓷电子密度和电性能的影响。实验发现：ZnO-TiO2-Bi2O3-CuOCr2O3压敏陶瓷基体和晶界缺陷态的电子密度均最高,其压敏电压最低;ZnO-TiO2-Bi2O3-CuO-MnO2压敏陶瓷晶界缺陷态的电子密度最低,其压敏电压比前者高;ZnO-TiO2-Bi2O3-CuO-Co2O3压敏陶瓷基体（晶粒内）的电子密度最低,其压敏电压较高;而ZnO-TiO2-Bi2O3-CuO-MnO2-Co2O3-Cr2O3压敏陶瓷基体和晶界缺陷态的电子密度均较低,其压敏电压VT和非线性系数ɑ最高,漏电流IL最小。

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简介：Recentadvancesontheuseofnanocarbon-basedelectrodesfortheelectrocatalyticconversionofgaseousstreamsofCO2toliquidfuelsarediscussedinthisperspectivepaper.Anovelgas-phaseelectrocatalyticcell,differentfromthetypicalelectrochemicalsystemsworkinginliquidphase,wasdeveloped.Thereareseveraladvantagestoworkingasphase,e.g.noneedtorecovertheproductsfromaliquidphaseandnoproblemsofCO2solubility,etc.Operatingundertheseconditionsandusingelectrodesbasedonmetalnanoparticlessupportedovercarbonnanotube(CNT)typematerials,longC-chainproducts(inparticularisopropanolunderoptimizedconditions,butalsohydrocarbonsuptoC8-C9)wereobtainedfromthereductionofCO2.Pt-CNTaremorestableandgiveinsomecasesahigherproductivity,butFe-CNT,particularusingN-dopedcarbonnanotubes,giveexcellentpropertiesandarepreferabletonoble-metal-basedelectrocatalystsforthelowercost.ThecontrolofthelocalizationofmetalparticlesattheinneroroutersurfaceofCNTisanimportactfactorfortheproductdistribution.ThenatureofthenanocarbonsubstratealsoplaysarelevantroleinenhancingtheproductivityandtuningtheselectivitytowardslongC-chainproducts.TheelectrodesfortheelectrocatalyticconversionofCO2arepartofaphotoelectrocatalytic(PEC)solarcellconcept,aimedtodevelopknowledgeforthenewgenerationartificialleaf-typesolarcellswhichcanusesunlightandwatertoconvertCO2tofuelsandchemicals.TheCO2reductiontoliquidfuelsbysolarenergyisagoodattempttointroducerenewablesintotheexistingenergyandchemicalinfrastructures,havingahigherenergydensityandeasiertransport/storagethanothercompetingsolutions(i.e.H2).

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简介：许多人都了解RADAR的概念一无线电探测和测距（Ra—dioDetectionandRanging），该技术通过发射无线电频率波在大气层传输，接触目标后反射回到系统进行处理，从而得出目标距离。近年来，电子扫描阵列使这一技术发生了革命性转变，可将无线电波以特定方向传输，无需机械移动。

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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.

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简介：Cu-Fecompositeoxideswerepreparedbyco-precipitationmethodandtestedforhigheralcoholsynthesisfromsyngas.TheselectivitytoC2+OHandC6+OHinalcoholdistributionwasveryhighwhilethemethaneproductfractioninhydrocarbondistributionwasratherlow,demonstratingapromisingpotentialinhigheralcoholssynthesisfromsyngas.ThedistributionofalcoholsandhydrocarbonsapproximatelyobeyedAnderson-Schulz-Florydistributionwithsimilarchaingrowthprobability,indicatingalcoholsandhydrocarbonsderivedfromthesameintermediates.TheeffectsofCu/Femolarratio,reactiontemperatureandgashourlyspacevelocity(GHSV)oncatalyticperformancewerestudiedindetail.ThesamplewithaCu/Femolarratioof10/1exhibitedthebestcatalyticperformance.Higherreactiontemperatureacceleratedwater-gas-shiftreactionandledtolowertotalalcoholsselectivity.GHSVshowedgreateffectoncatalyticperformanceandhigherGHSVincreasedthetotalalcoholselectivity,indicatingthereexistedvisibledehydrationreactionofalcoholintohydrocarbon.