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:IntheinterlayerexpansionofthelayeredzeoliteprecursorCOK-5,aSn,salt,bis(2,4-pentanedionate)-dichlorotin[Sn(acac)2Cl2],insteadofasilylatingagentwasusedtolinkthelayersat180°C.Theobtainedmaterial,whichisdesignedasSn-COE-5,showsashiftofthefirstXRDreflection,whichisverysimilartothatofCOK-5interlayerexpandedwithdichlorodimethylsilane(DCDMS),indicatinganincreaseininterlayerdistance.X-raydiffraction(XRD),N2sorptionisotherms,inductivelycoupledplasma(ICP),andX-rayphotoelectronspectroscopy(XPS)supporttheincorporationofisolatedSnsitesinthesample.Intheconversionofglucosetolevulinicacid,Sn-COE-5exhibitsmuchhigheractivitythanCOK-5,whichisduetothepresenceofLewisacidicsitesintheSn-COE-5.
简介:摘要采用溶胶-凝胶法制备了Al2O3-ZrO2复合溶胶膜,研究了化学组成和添加剂对复合溶胶的影响。结果表明,当Al2O3/ZrO2=1,DMF=40vol%时,可得到澄清透明,粘度适中,稳定性好,且凝胶干燥后几乎无开裂的溶胶膜
简介:TheinfluenceofNa2SO4ontheformationofZnOwhiskerswasinvestigatedinthispaper.ZnOwhiskerswithaspectratiosofupto50weresynthesizedbydissolvingε-Zn(OH)2precursorinNaOH/Na2SO4solutionatroomtemperature,followedbyagingoftheresultingsolutionat140℃for6h.Fouriertransforminfraredspectroscopy,Ramanspectroscopy,andX-rayphotoelectronspectroscopyanalysesrevealedthatSO42-ionswereprimarilyadsorbedonthe(100)planeoftheZnOwhiskersviaanouter-spherecomplexconfiguration(O-H…O),therebypromotingtheone-dimensionalgrowthofZnOwhiskersalongthec-axis.
简介:Lifetimemeasurementsoflow-lyingexcitedstatesin87Zrand87Nbhavebeenperformedviaandcoincidences.The124MeV32SbeamwasdeliveredfromtheSector-FocusingCyclotron(SFC)oftheHeavyIonR-esearchFacilityinLanzhou(HIRFL).Theparentnuclei87Nband87Mowereproducedbytherespectivereactions58Ni(32S,3p)and58Ni(32S,2p1n),atabeamenergy100MeVthroughthe8mAldegrader.
简介:目的:观察外源给予H2O2对C2C12细胞中UII/UT系统表达的影响。方法:培养小鼠肌原细胞系C2C12细胞株,应用胎盘蓝染色和测定细胞培养液中LDH的含量检测H2O2对细胞损伤的影响,应用放射免疫的方法检测细胞培养液和裂解液中UII的含量,应用RT-PCR法测定C2C12中UTmRNA的表达,应用WesternBlot检测不同浓度H2O2对肌原细胞系C2C12中UT蛋白表达的影响。结果:外源给予不同浓度的H2O2,C2C12细胞裂解液中UII的含量各组间无明显差异,但增加了细胞孵育液中UII的含量,10-4M和10-3M时分别增加了83.1%(p〈0.01)和94.5%(P〈0.01)。低浓度H2O2(0.5×10-6M,10-6M,10-5M,10-4M)刺激明显增加了UTmRNA的表达,而高浓度的H2O2(10-3M)刺激反而使UTmRNA的表达降低。高浓度的H2O2(10-6M,10-5M,10-4M,10-3M)刺激使UT蛋白表达分别增加了200.1%、255.6%、111.1%和100.1%(均p〈0.05)。结论:H2O2作为T2DM发病因素之一的活性氧族,可能是T2DM时骨骼肌组织中UII/UT系统表达增加的一个因素。
简介:构建了一种基于R^2LC^2(可靠、冗余、损耗、特性、成本)的中高压多电平统一电能质量调节器(UnifiedPowerQualityConditioner,UPQC)拓扑评估体系.选定多种应用于UPQC的多电平拓扑结构类型,建立多电平UPQC拓扑结构的损耗模型、故障模型、仿真模型、冗余模型和器件模型,分别用以分析并形成损耗与拓扑关系、拓扑可靠性、暂稳态特性、系统稳定性、结构与成本关系的评价指标.结合五种评价指标的相互影响关系,建立层次分析模型,定量得到五种评价指标的权重系数,构造成对比较矩阵,计算排序权向量,全面分析多种多电平UPQC拓扑结构的整体性能,实现多电平UPQC拓扑结构的综合准确评估,提供多电平UPQC变流器拓扑结构类型的选择依据.选取级联H桥、模块化多电平变流器和换桥臂多电平变流器为实际应用范例,验证了所提评估体系的可行性.
简介:某型号火药起动器壳体采用新材料1Cr11Ni2W2MoV,需要进行焊接工艺研究。针对此产品进行了自动TIG焊工艺试验,对比了S-659和HGH367两种焊丝以及不同焊接电流、焊接速度配合所焊焊缝的组织及性能。结果表明,采用S-659焊丝以及大电流高速焊的"大规范"的焊接参数所焊焊缝,成形、组织及性能均更优,焊缝质量满足QJ1842-95Ⅰ级要求。在此基础上进行了产品模拟件及正式产品的焊接,所焊产品经X光检查合格,液压、气密试验考核合格,满足使用要求。
简介:ToimprovethemechanicalpropertiesofWC-Al2O3composites,theeffectsoftraceamountofCeO2additivesonthemicrostructureandmechanicalpropertiesoftheWC-Al2O3compositespreparedbyhotpressingwereinvestigated.TheresultsrevealedthattheWC-Al2O3compositesdopedwith0.1%CeO2possessedrefinedmicrostructureandenhancedmechanicalpropertiescomparedwiththatoftheundopedWC-Al2O3composites.TraceCeO2suppressedthedecarburizationofWC,promotedthemicrostructuralrefinement,andimprovedtheinterfacecoherenceoftheWCmatrixandAl2O3.When0.1%CeO2wasaddedtotheWC-Al2O3composites,theeffectofCeO2resultedintheachievementofarelativedensityof98.82%withanexcellentVickershardnessof16.89GPa,combiningafracturetoughnessof9.85MPa·m1/2withanacceptableflexuralstrengthof1024.05MPa.
简介:Amolybdenumdisulfide(MoS2)saturableabsorberwasfabricatedbythermallydecomposingtheammoniumthiomolybdate.ByusingtheMoS2absorber,acompactdiode-pumpedpassivelyQ-switchedTm:GdVO4laserhasbeendemonstrated.AstableQ-switchedlaserwithrepetitionratesfrom25.58to48.09kHzwasachieved.Maximumaverageoutputpowerwas100mWwiththeshortestpulsedurationof0.8μs.Maximumpulseenergyis2.08μJatcenterof1902nm.
简介:Theroleofpulseparametersonnanoparticlepropertyisinvestigatedself-consistentlybasedonacoupleoffluidmodelandaerosoldynamicsmodelinacapacitivelycoupledparallel-plateacetylene(C2H2)discharge.Inthismodel,themasscontinuityequation,momentumbalanceequation,andenergybalanceequationforneutralgasaretakenintoaccount.Thus,thethermophoreticforceariseswhenagastemperaturegradientexists.Thetypicalresultsofthismodelarepositiveandnegativeiondensities,electronimpactcollisionsrates,nanoparticledensity,andchargedistributions.Thesimulationisperformedfordutyratio0.4/0.7/1.0,aswellaspulsemodulationfrequencyfrom40kHzto2.7MHzforpureC2H2dischargesatapressureof500mTorr.Wefindthatthepulseparameters,especiallythedutyratio,haveagreataffectonthedissociativeattachmentcoefficientandthenegativedensity.Moreimportantly,bydecreasingthedutyratio,nanoparticlesstarttodiffusetothewall.Undertheactionofgasflow,nanoparticledensitypeakiscreatedinfrontofthepulseelectrode,wherethegastemperatureissmaller.