简介：WehavestudiedtheMossbauereffectofYBa2Cu2.88Fe0.12O7-xsuperconductiveoxidefrom78to273K.TwominimaofrecoillessfractionandDebyetemperaturewerefoundnear110Kand220K.Itmeansthatlatticesofteninghappenednearthesetwotemperatures.Wealsoobservedminimaofisomershiftnear110Kandquadrupolesplittingincreasewhentemperatureislowerthan110K.Wesuggestthatlatticesofteningwouldleadtothedisplacementofoxygenatoms.Thismayberelativetosuperconductivetransition.

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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.

简介：利用室温液相还原、晶种生长的方法,成功的制备了大小形貌均一、性能稳定且具有磁性的Fe3O4@Cu2O复合纳米粒子,并且对制备的Fe3O4@Cu2O纳米粒子进行了光催化性能的研究.在以紫外光为光源的照射下,合成的Fe3O4@Cu2O纳米粒子对有机染料甲基蓝溶液起到很好的降解作用.更重要的是,在外加磁场的作用下,Fe3O4@Cu2O纳米粒子容易回收,具有良好的可循环利用性能.

简介：摘要采用溶胶-凝胶法合成掺杂La的六角晶系Z型钡铁氧体Ba3-xLaxCo2Fe24O41，并对其吸波性能进行研究。实验结果表明，镧的最大添加量为x=0.3，此时Ba3-xLaxCo2Fe24O41可以形成完整的物相结构，对其吸波性能研究分析表明，适量的掺杂镧可以提高Z型钡铁氧体的吸波特性，最大衰减量为-26.5dB，有效带宽为5GHz。

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简介：Poly(methylmetacrylate)(PMMA)/Y0.0025Si0.025Ba0.9725(Ti(0.9)Sn0.1)O3(YBTS)composites在YBTS的不同重量比率被准备(0wt%，5wt%，10wt%和20wt%YBTS)招待以便在PMMA的电、光的性质上调查YBTS增加的效果。电的性质(阻抗，绝缘的经常的绝缘的损失和交流电导率)在频率范围被学习10kHz-1MHz并且在温度范围20鈥?0掳C。在增加YBTS的内容之上陶器，我们在在绝缘的经常的、绝缘的损失和PMMA的交流电导率的阻抗和增加观察了减小主人。我们也发现在高YBTS内容的松驰过程由于在离子的传导性的松驰。吸收系数(伪)在波长范围被决定了230鈥?在为所有YBTS-PMMAcomposites的房间温度的00nm。而且，YBTS的增加陶器高度特别在300nm下面提高PMMA主人的紫外吸收。对PMMA主人陶器的20wt%YBTS的增加减少从5eV的光精力差距到3.41eV。关联在之间电，光并且SEM结果被报导。关键词电-光-PMMA，陶器-铁电体-Composites

简介：Жил-бbIл　yчебHиK.Ъыл　OHHeHбbьIЙ,aдOCTаTOчHOCTаpыЙ.ПoHeMyзaHиMалиCbpeбяTaCTapаTeлbHыe,HepиCOBали　HaCTpaHицaX.

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简介：МИРＢ２０００ГОДУ参考译文２０００年的世界美国环境保护委员会和国务院的专门委员会对２０００年地球文明的发展作了预测。在假设不发生任何社会经济或工艺革命，保持现有工业发展的性质的条件下，该委员会得出了一些非常悲观的结论。下面介绍其中几项结论。地球...

简介：1.IntroductionSofarthemicrostructureandcoercivityofSm（Co,Cu,Fe,Zr）7.4alloyhavebeenstudiedindetailbyvariousauthors.TheeffectofZr-richlaminarphasestructureonthehighcoecivityofalloyismoreattractive.Thechangesofmagnetic

简介：1.IntroductionLightrareearthadditioncanremarkablyenhancetheservicelifeofFe-Cr-Alalloyforelectricalheatingelement,butitscontentinthealloymustbecontrolledbelowthelevelof0.1wt-%.Whenthecontentexceedsthat,theperformance

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简介：铝电解用连接导杆是连接阳极和电源的关键部件，在高温电解条件下起承载阳极的作用和承担大电流导通的任务，其原材料必须是导电的、有一定强度和高致密度的。该文采用粉末冶金方法制备Cu-Ni-Fe-Co合金材料，研究烧结温度对其密度及力学性能的影响，进而确定制备高致密度导杆合金材料的最佳烧结工艺。结果表明：该合金的相对密度随烧结温度的提高而提高，当烧结温度为1250℃时能获得综合性能较好、相对密度为95.2％、晶粒尺寸为20-30μm的Cu-Ni-Fe-Co合金材料，其性能完全满足制作铝电解连接导杆的要求。

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简介：TheroleoftemperatureontheoxidationdynamicsofCu2OonZnO(0001)wasinvestigatedduringtheoxidationofCu(111)/ZnO(0001)byusingoxygenplasmaastheoxidant.AtransitionfromsinglecrystallineCu2O(111)orientationtomicro-zonephaseseparationwithmultipleorientationswasrevealedwhentheoxidationtemperatureincreasedabove300°C.TheexperimentalresultsclearlyshowtheeffectoftheoxidationtemperaturewiththeassistanceofoxygenplasmaonchangingthemorphologyofCu(111)filmandenhancingthelateralnucleationandmigrationabilitiesofcuprousoxides.Averticaltop-downoxidationmodeandalateralmigrationmodelwereproposedtoexplainthedifferentnucleationandgrowthdynamicsofthetemperature-dependentoxidationprocessintheoxidationofCu(111)/ZnO(0001).

简介：采用丝印法在铝基板上制备具有低室温电阻率、适中热敏常数的负温度系数BaCo0.02ⅡCo0.04ⅢBi0.94O3/Ba0.5Bi0.5Fe0.9Sn0.1O3复合热敏厚膜。采用数字多用表、吉时利2400和阻抗分析仪对热敏厚膜的电学性能进行表征。结果表明：随着Ba0.5Bi0.5Fe0.9Sn0.1O3含量从0.05增加至0.25,厚膜的室温电阻率、热敏常数和峰值电压均有所增加且分别处于1.47-26.5Ω·cm、678-1345K和18.9-47.0V范围内,厚膜峰值电压对应的电流也有所降低且处于40-240mA范围。阻抗谱测试表明,这些热敏厚膜表现出非正常的异质电学微结构行为,由高阻态的晶粒和较低电阻态的晶界区域构成。由此可知,在BaCo0.02ⅡCo0.04ⅢBi0.94O3中添加Ba0.5Bi0.5Fe0.9Sn0.1O3改善了热敏行为但也恶化了电流特征.

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.

简介：BondingofAl2O3tocuisperformeddirectlyusingTifoilattemperatureof1273K.Themicrostructureofthejointinterfaceisinuestigatedthroughscanningelectronmicroscope（SEM）,electron.probemicroanalysis（EPMA）andX-raydiffraction（XRD）.theeffectoftheinitialtifoilthicknessonthereactionlayerthicknessandthejointStrengthareinvestigated.