Study on Magnetic Responsibility of Rare Earth Ferrite／Polyacrylamide Magnetic Microsphere

Magneticpolymermicrospherecanbeseparatedquicklyundermagneticfieldandithasgotwideappli cationinmanyfields ,suchascellseparationetc .Themicrospheremustpossesshighmagneticresponsibili ty ,sothatmagneticseparationisquickandconve nient.Themagneticresponsibilit…     

Preparation and Characterization of Eu／MCM-41 Mesoporous Composite Material

Nanosized mesoporous molecular sieve MCM-41 was synthesized with tetraethyl orthosilicate (TEOS) as the source of silica and cetyltrimethyl-ammonium bromide (CTAB) as the template. The photoluminescent functional supramolecule Eu(DBM)3phen/MCM-41 between the nanosized MCM-41 and Eu(DBM)3phen was prepared in chloroform, and characterized by XRD, HRTEM, IR and fluorescent spectroscopy.     

Synthesis and Characterization of Gadolinium Doping M-type Hexagonal Barium Ferrite Ultrafine Powders

Becausepermanentbariumferritematerialpos sessesrelativelyhighsaturationmagnetization ,greatcoerciveforceandhighmagneticanisotropyfieldaswellasexcellentchemicalstabilityandcorrosionresis tance ,ithasbeenwidelyusedastraditionalperma nentmagnets ,high densitymagneticandmagneto op ticrecordingmedia ,microwavefilters[1,2 ] .Thusthestudyonthesynthesisofmagnetoplumbite typebariumferriteisconsiderablyimportanttotheelectronicandmagneticmaterialsindustry .Duringthelastfewdecades ,peoplehavemadegreateffo…     

Preparation of Rare Earth Doped Alumina-Siloxane Gel and Its ER Effect

Poly(methyl methacrylate) (PMMA) was used to wrap alumina-siloxane sol through emulsion polymerization. A kind of suspensions with notable ER effect was produced by fully mixing the prepared microcapsule with silicon oil. Meanwhile a series of PMMA wrapped alumina - siloxane gel doped with rare earths was obtained and its ER effect was tested, like viscosity of different rare earth ion doped samples in different powder concentrations and at different temperatures, at the same time, leak current density and dielectric constant were measured. Resuits show that the ER effect of this suspension is remarkable, and its stability is much better. The condition of emulsion polymerization and the mechanism of effect are discussed.     

Preparation and Characterization of Microporous Nano-Tungsten Trioxide and Its Photocatalytic Activity after Doping Rare Earth

Recently,heterogeneousphotocatalyticoxidation decompositionoforganiccontaminantshasbeenstud iedkeenlyinvariousfields.WO3isknownasamulti functionalmaterialapplicableforelectrochromicdis playdevice(ECD),semiconductorgassensor,cata lystetal.WO3,whosebandgapenergyhasbeenesti matedtobe2.5eV,hasthepotentialabilitytophoto catalyzeunderirradiationofvisiblelightofwavelength相似文献   

Influences of Niobium and Zirconium Additions on Crystallization Behaviors and Magnetic Properties of Melt-Spun （Nd, Pr）2Fe14B／α-Fe Alloys

Effects of Nb and Zr substitutions on the crystal]ization behaviors and magnetic properties of melt-spun (Nd,Pr)2Fe14B/α-Fe alloys were studied.The results show that for (Nd0.4Pr0.6)8.5Fe85.5B6 ribbons, the metastable (Nd,Pr)3Fe62B14 precipitates after the initial crystallization of α-Fe and decomposes into the final mixture of (Nd,Pr)2Fe14B and α-Fe. For(Nd0.4 Pr0.6)8.5 Fe84.5 Zr0.5 Nb0.5B6 ribbons, however,(Nd, Pr)2Fe14B and α-Fe phases precipitate simultaneously. This indicates that both Nb and Zr dopingcan avoid the formation of metastable phase and!     

Synthesis of YAG：Ce^3＋ Phosphor by Polyacrylamide Gel Method and Promoting Action of α-Al2O3 Seed Crystal on Phase Formation

YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some intermediate phases, including θ-Al2O3, YAM and YAP, are formed when calcining polyacrylamide gel, however, the pure YAG phase can be formed directly when calcining polyacrylamide gel with α-Al2O3 as seed crystal. These facts show that the existence of α- Al2O3 seed crystal can block the formation of θ-Al2O3, YAM and YAP, and accelerate its reaction with Y2O3 to form YAG phase directly at lower temperature. The emission peak of prepared YAG ： Ce^3 ＋ phosphor is wide with maximum at 550 nm and the exitation band has two peaks, the major one is around at 460 nm, which matches the blue emission of GaN LED and is suitable for the assemble of white LED. Some fluxes can enhance the photoluminescence intensity of phosphor particles, that can be attributed both to the improvement of crystallization processes of YAG and to the stabilization of trivalence cerium ion in YAG：Ce^3 ＋.     

Preparation and Structure Characterization of Rare Earth Doped Alumina-Siloxane Gel and Its Modification on ER Effect

A series of samples of alumina-siloxane gel wrapped by poly (methyl methacrylate) and doped with rare earths such as lanthanum, praseodymium, yttrium, gadolinium and europium were prepared. The structure features were characterized by micrograph, X-ray fluorescence spectrum, X-ray diffraction spectrum, Fourier transform infrared spectrum and differential thermal analysis.Tests indicate that rare earths modify the electrorheological effects of the stable suspensions composed of samples stirred with silicon oil.     

Preparation of BaMgAl10O17 ：Eu^2＋ and Its Phase Behavior in Microemulsion System

BaMgAl10O17 ： Eu^2＋ （BAM） was prepared in the microemulsion system and its phase behavior was studied. There exists a small region in the reverse microemulsion system where the dispersed particles are of spherical form. In this way, BAM blue phosphor with good dispersion can be synthesized. The microemulsion phase diagrams of the pseudo-ternary system （Triton X-100/cosuffactant-oil-BAM brine） were first established intuitively by the dilution method. The microstructure of microemulsions was determined through eyeballing, conductance technique, and polar optical microscopy. Its phase behavior is affected by various factors, such as temperature （room temperature, 30, 40 ℃）, oil, surfactants, and cosurfactants in microemulsions. According to the phase diagrams, the microemulsion system of Triton X-100/1-hexanol-hexane-BAM brine was chosen to prepare the precursor. The BAM phosphor can be obtained via sintering the precursor at a comparatively low temperature. The phosphors were characterized by XRD and vacuum ultraviolet （VUV） spectra.     

Preparation and Characterization of CeO2-ZrO2 Solid Solution Ultrafine Particles Using Reversed Microemulsion

The development of the TWCs (three-way cata-lysts) was dictated bythe need to si multaneously con-vert the three main pollutants inthe exhaust gases ,i .e .,hydrocarbons (HCs) ,COand NOxpresent in theautomotive exhaust to H2O, CO2and N2[1]. Highestconvers…     

稀土磁性复合微球的制备及表征

以聚乙二醇磁性胶体粒子为种子 ,运用分散聚合法 ,同时掺入稀土离子 ,制备出表面配位有稀土离子的磁性聚苯乙烯微球 ,该微球粒径为 6 0～ 180 nm,考察了稀土磁性微球的形态和结构。并用电镜、原子吸收光谱、红外光谱对其性质进行了表征。     

纳米稀土铁氧体磁性颗粒的制备研究

采用湿化学方法研究制备纳米稀土铁氧体磁性颗粒，研究纳米稀土铁氧体颗粒制备过程中主要影响因素，如pH和RE^3＋等对纳米稀土铁氧体颗粒粒径及磁性能的影响；同时对纳米Dy铁氧体颗粒的形貌、粒度分布、晶型结构及磁性能进行了分析和研究。研究发现轻稀土对Fe3O4颗粒的磁性有削弱作用，不宜掺杂；重稀土元素掺杂是提高铁氧体磁性颗粒磁性能的有效途径，改善磁性能的强弱顺序为Dy^3＋〉Gd^3＋〉Er^3＋。制备的Dy铁氧体颗粒的平均粒径为9．6nm，比饱和磁化强度98．27A·m^2·kg^-1，具有超顺磁特性。同时讨论了Dy^3＋在Fe3O4的晶体结构中取代Fe离子增强磁性能的可能形式。     

干法氟化制备高纯金属镝的工艺研究

介绍了一种制备无水高纯氟化镝的新方法。在氟化炉内的镍制料盘中直接完成了Dy2O3和无水氟化氢气体的氟化反应，然后将钙热还原DyF3制得的粗镝进行熔盐萃取提纯处理，用此式敢可使工业规模化生产的镝金属中的氧，氟含量均小于0.02%，使金属镝的纯度达99.9%以上。     

Study on Synthesis and Polymerization of Mono (isopropylmaleate oyloxyl) Diisopropoxyl Dysprosium

Ｉｎｔｈｅｅａｒｌｙ1980ｓ,ｒａｒｅｅａｒｔｈｃｏｎｔａｉｎｉｎｇｐｏｌｙｍｅｒｓｗｅｒｅｐｒｅｐａｒｅｄ[1].Ｔｈｅｎｅｗｍａｔｅｒｉａｌｓｃｏｍｂｉｎｅｄｔｈｅｏｐｔｉｃａｌ,ｅｌｅｃｔｒｏｎｉｃｏｒｍａｇｎｅｔｉｃｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｒａｒｅｅａｒｔｈｉｏｎｓｗｉｔｈｔｈｅｐｒｏｐｅｒｔｉｅｓｏｆｏｒｇａｎｉｃｐｏｌｙｍｅｒ.Ｓｏｔｈｅｙｍｉｇｈｔｂｅｕｓｅｄａｓｆｌｕｏｒｅｓｃｅｎｔ,ｌａｓｅｒ,ｍａｇｎｅｔｉｃｍａｔｅｒｉａｌｓｏｒｏｐｔｉｃａｌｐｌａｓｔｉｃｓ[2,3].Ｈｏｗｅｖ…     

镝掺杂W型钡镍铁氧体的制备及电磁性能研究

采用固相反应法制备了掺镝W型钡镍铁氧体粉体。利用X射线衍射仪及扫描电子显微镜对其晶体结构及微观形貌进行分析,使用微波网络分析仪对其微波电磁性能进行研究。结果表明:1350℃时,不同Dy掺杂量下均形成了纯度较高的W型钡镍铁氧体,六角片状结构完整。在15～18GHz频段:μ″,tanμ值随Dy掺杂量的增加而增大,掺镝摩尔分数x=0.08时达到最大。     

Sm-Fe-C复合纳米粉的制备及磁性

在氢等离子体电弧法制备Sm-Fe纳米粉过程中,增加原料中Fe的含量有利于形成Sm-Fe相,在真空烧结炉里进行碳化处理过程中,碳化时间过长,会出现Sm2C和α-Fe相,反之,内部出现未碳化的钐铁相区、碳浓度分布不均匀或碳浓度低,都导致磁性能降低。在500℃碳化4h后,随炉冷却至室温,样晶的磁性能为最佳,达到Ms=89.0emu/g,Mr=13.0emu/g,Hc=212Oe,居里温度同碳化时间关系不大,保持在460℃左右。对Sm-Fe-C微观结构及磁性能等进行了研究。     

Preparation and Characterization of Rare Earth Composite Materials Radiating Far Infrared for Activating Liquefied Petroleum Gas

Rare earth composite materials radiating far-infrared rays were prepared according to far infrared absorption spectrum of main component in liquefied petroleum gas (LPG). The composite materials were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transformed infrared spectra(FTIR). The results show that after the composite materials were calcined at 873 K for 4 h, FTIR spectra of rare earth composite materials display two new peaks at 1336 and 2926 cm-1 available for activating LPG.     

Preparation, Characterization and Photo-Catalytic Behavior of Y_2O_3/TiO_2 Composite Semiconductor Nanopowder

ＴｉＯ2 ｐｈｏｔｏ ｃａｔａｌｙｓｉｓｈａｓｂｅｅｎａｆｏｃｕｓｏｆｎｕｍｅｒｏｕｓｉｎｖｅｓｔｉｇａｔｉｏｎｓｉｎｒｅｃｅｎｔｙｅａｒｓ ,ｐａｒ ｔｉｃｕｌａｒｌｙｏｗｉｎｇｔｏｉｔｓａｐｐｌｉｃａｔｉｏｎｆｏｒｔｈｅｃｏｍ ｐｌｅｔｅｍｉｎｅｒａｌｉｚａｔｉｏｎｏｆｕｎｄｅｓｉｒａｂｌｅｏｒｇａｎｉｃｃｏｎ ｔａｍｉｎａｎｔｓｔｏＣＯ2 ,Ｈ2 Ｏａｎｄｉｎｏｒｇａｎｉｃｃｏｎ ｓｔｉｔｕｅｎｔ[1] .Ｈｏｗｅｖｅｒ,ｐｈｏｔｏ ｏｘｉｄａｔｉｏｎｉｓａｌｍｏｓｔｎｏｔｉｎｄｕｓｔｒｉａｌｌｙａｐｐｌｉｅ…     

锰锌铁氧体粉制备技术综述

综述了近几年来软磁铁氧体粉 (特别是锰锌铁氧体粉 )的制备方法、研究现状及应用前景