简介:为研制具有较宽频带微波吸收性能的材料,采用机械合金化法制备CoxFe80-xSi20(x=0,6,10,14摩尔百分数)合金粉体,使用SEM、XRD和矢量网络分析仪等测试手段,研究了合金粉体微观结构及Co-Fe-Si合金微波吸收性能。结果表明:制备的合金粉末呈片状,主要由-Fe相组成;Co的添加使Co-Fe-Si合金出现两个微波吸收峰。在较高频段处的微波吸收峰值随Co的添加先增大后减小。在涂层厚度为1.8mm时,x=10的合金低频处的反射率最小值最小,合金吸波峰频率和峰值分别为6.2GHz和-14.8dB,合金在高频处吸波峰频率和峰值分别为18GHz和-8.8GHz,合金反射率低于-5dB的带宽达14GHz,具有良好的微波吸收宽频效应。
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简介:探讨用等离子体喷涂方法制备降低较高强度材料与U-Nb合金之间的摩擦性能的减磨层的可行性以及这些减磨层的摩擦特性。选用Sn为软涂层,ZrO2为硬涂层。采用SulzerMETCO9M等离子体喷涂机制备了Sn单层、ZrO2单层、Sn/ZrO2双层、Sn+ZrO2混合层等4种涂层。利用CSEM型销盘型摩擦磨损试验机分析了半径为3mm的U-Nb合金对偶销在涂层上滑动时的干摩擦特性,滑动速度分别为0.42,6.4,26.16cm/s。涂层为典型的等离子体喷涂涂层形貌。表面为Sn的涂层颗粒熔合状况和致密性比ZrO2单层好,其粗糙度低,Sn+ZrO2混合涂层表面形貌与ZrO2单层相近。Sn和ZrO2分别以bcc结构的Sn和四方结构ZrO2结构存在。
简介:Low-energypartial-waveπNscatteringdataisreexaminedwiththehelpoftheproductionrepresentationofpartial-waveSmatrix,wherebranchcutsandpolesarethoroughlyunderconsideration.Theleft-handcutcontributiontothephaseshiftisdetermined,withcontrolledsystematicerrorestimates,byusingtheresultsofO(p^3)chiralperturbativeamplitudesobtainedintheextended-onmass-shellscheme.InSnandPuchannels,severediscrepanciesareobservedbetweenthephaseshiftdataandthesumofallknowncontributions.Statisticallysatisfactoryfitstothedatacanonlybeachievedbyaddingextrapolesinthetwochannels.WefindthataSnresonancepolelocatesat√zr=(0.895±0.081)—(0.164±0.023)iGeV,onthecomplexs-plane.Ontheotherhand,aFnvirtualpole,asanaccompanyingpartnerofthenucleonbound-statepole,locatesat√zv=(0.966±0.018)GeV,slightlyabovethenucleonpoleontherealaxisbelowthreshold.Physicaloriginofthetwonewlyestablishedpolesisexploredtothebestofoiirknowledge.ItisemphasizedthattheO(p^3)calculationgreatlyimprovesthefitqualitycomparingwiththepreviousO(p^2)one.
简介:Twoseriesofmixedoxides,CoAlMandMgAlM(M=Cr,Mn,Fe,Co,Ni,Cu),werepreparedbycalciningtheircorrespondinghydrotalcite-likecompounds(HTLc).TheratioofMg:Al:M(orCo:Al:M)was3:1:1.ThecatalyticactivityofallsamplesforthereactionofNO+COwasinvestigated.TheresultsshowedthattheactivityofCoAlMwasmuchhigherthanthatofMgAlM.ThestructureandthepropertyofredoxwerecharacterizedbyXRDandH2-TPR.TheresultsindicatedthatonlyMgOphasewasobservedaftercalciningMgAlMhydrotalcites,andthetransitionmetalsbecamemorestable.Thespinel-likephaseappearedinallofCoAlMsamplesafterthecalcination,andthetransitionmetalswerechangedtobemoreactive,andeasilyreduced.TheactivitiesofthreeseriesofmixedoxidesCoAlCuobtainedfromdifferentpreparationmethods,differentratioofCo:Al:Cuandatdifferentcalcinationtemperatures,werestudiedindetailforproposingthemechanismofreaction.TheabilityofadsorptionofNOandCO
简介:COandformaldehyde(HCHO)oxidationreactionswereinvestigatedovermesoporousAg/Co3O4catalystspreparedbyone-pot(OP)andimpregnation(IM)methods.Itwasfoundthattheone-potmethodwassuperiortotheimpregnationmethodforsynthesizingAg/Co3O4catalystswithhighactivityforbothreactions.ItwasalsofoundthatthecatalyticbehaviorofmesoporousCo3O4andAg/Co3O4catalystsforthebothreactionswasdifferent.AndtheadditionofsilveronmesoporousCo3O4didnotalwaysenhancethecatalyticactivityoffinalcatalystforCOoxidationatroomtemperature(20C),butcouldsignificantlyimprovethecatalyticactivityoffinalcatalystforHCHOoxidationatlowtemperature(90C).Thehighsurfacearea,uniformporestructureandtheprettygooddispersiondegreeofthesilverparticleshouldberesponsiblefortheexcellentlow-temperatureCOoxidationactivity.However,forHCHOoxidation,theadditionofsilverplayedanimportantroleintheactivityenhancement.AndthesilverparticlesizeandthereducibilityofCo3O4shouldbeindispensableforthehighactivityofHCHOoxidationatlowtemperature.
简介:IntroductionIn2O3·Snfilmshavehightransparency(>95%)withinthevisiblespectralregion,lowresistivity(10-2—10-4ohm·cm)atroomtemperatureandsuperiorthermalstability.Thesefilmshavebeenappliedtosolarcells,electronicsandphotoelectronicsfields.Inrecentyears,organometallic-CVDmethodhasemergedasasuccessfulalternatetothephysicalmethodsandgeneralCVDforthegrowthofthesefilms.TheMO-CVDtech-
简介:Dopantsanddefectsareimportantinsemiconductorandmagneticdevices.Strategiesforcontrollingdopinganddefectshavebeenthefocusofsemiconductorphysicsresearchduringthepastdecadesandremaincriticaleventoday.Co-dopingisapromisingstrategythatcanbeusedforeffectivelytuningthedopantpopulations,electronicproperties,andmagneticproperties.Itcanenhancethesolubilityofdopantsandimprovethestabilityofdesireddefects.Duringthepast20years,significantexperimentalandtheoreticaleffortshavebeendevotedtostudyingthecharacteristicsofco-doping.Inthisarticle,wefirstreviewthehistoricaldevelopmentofco-doping.Then,wereviewavarietyofresearchperformedonco-doping,basedonthecompensatingnatureofco-dopants.Finally,wereviewtheeffectsofcontaminationandsurfactantsthatcanexplainthegeneralmechanismsofco-doping.
简介:利用methoxysilyl一半的水解作用和冷凝作用,器官无机的混血儿(N-isopropylacrylamide-co-acrylamide-co-3-(trimethoxysilyl)propylmethacrylate)poly,P(NIPAM-co-AM-co-TMSPMA)microgels经由二个不同方法被准备。第一个方法是microgels是从crosslinkable的fabricated以后线性P(NIPAM-co-AM-co-TMSPMA)terpolymer在terpolymer的更低的批评答案温度(LCST)上面的水的答案。为第二个方法,microgels被常规表面活化剂直接综合NIPAM,AM,和TMSPMA的免费乳剂copolymerization。结果的P(NIPAM-co-AM-co-TMSPMA)microgels的水动力学直径和稳定性强烈取决于microgel的pH和温度水的答案。microgels的水动力学直径与增加测量温度减少了。microgels的阶段转变温度被发现在34附近吗??
简介:第三的Ni-5%Cu-5%Sn和Ni-10%Cu-10%Sn合金的液体状态undercoolability和水晶生长动力学被玻璃fluxing方法调查。在这二合金,304K的试验性的最大的undercoolings(0.18TL)和286K(0.17TL)被完成,树枝状的生长速度分别地达到39.8和25.1m/s。从进equiaxed结构的粗糙的树突的形态学的转变发生并且谷物尺寸(Ni)当undercooling增加时,显著地分阶段执行减少。格子常数和microhardness与undercooling的改进显然增加。Cu和Sn溶质内容的丰富减少树枝状的生长速度,当时提高格子常数和microhardness(Ni)阶段。
简介:Ba1.0Co0.7Fe0.2Nb0.1O3-δ(BCFN)oxidewithperovskitecubicstructurewassynthesizedbysolidstatereactionmethod.CO2corrosionofBCFNmembranewasinvestigatedbyX-raydiffraction(XRD),scanningelectronmicroscopy(SEM),diffusereflectanceinfraredFouriertransformedspectroscopy(DRIFT)andX-rayabsorptionfinestructurespectroscopy(XAFS).Cobalt(Co)K-edgeabsorptionspectraofBCFNannealedinCO2revealthattheoxidationstatesofCoinallthesampleswerelargerthan+3andtheydecreasedwiththeincreaseofcalcinationtime.At800℃,1%CO2introducedintoHecouldspeedupthereductionofCocationsincomparisonwithpureHe.Inaddition,sulfateionsinthebulkofBCFNmembranepreferredtomigratetothesurfaceunderCO2calcinationandformmonoclinicBa(CO3)0.9(SO4)0.1besidesorthorhombicwitherite.Moreover,SEMresultsindicatethatthenucleationandgrowthofcarbonatesgrainsstartedatthegrainboundaryofthemembrane.