非水凝胶原位聚合法制备含铽PMMA及其荧光性质研究

通过三异丙氧基铽[Tb(OPr^i)3]与甲基丙烯酸甲酯(MMA)混合形成的凝胶体在偶氮二异丁腈(AIBN)引发下进行原位聚合的方法获得含铽的聚甲基丙烯酸甲酯，用红外光谱(IR)、动态机械热分析(DMTA)、热失重(TG)、荧光光谱(FS)、溶解性等手段对其进行表征。结果表明：Tb(OPr^i)3中的Tb^3 离子与MMA中的C=O存在很强的配位作用，并导致进一步交联，形成了具有交联网状结构的含铽聚合物。该聚合物具有优异的耐热性与耐溶剂性、高贮能模量、并能发射很强的Tb^3 离子的^5D4→^7F6，^5D4→^7F5，^5D4→^7F4，^5D4→^7F3跃迁的特征荧光。     

铽含量对耐热钕铁硼永磁材料的磁性能的影响

研究了重稀土元素铽（Ｔｂ）的含量对末冶金烧结耐热型（Ｎｄ,Ｄｙ,Ｔｂ）２（Ｆｅ,Ｃｏ,Ｎｂ,Ｇａ）１４Ｂ永磁材料的乘磁（Ｂｒ）磁化强度矫顽力（Ｈｃｊ）和温度系数（μＢｒ）的影响。实验中,采用Ｔｂ等量取代原合金中的一部分Ｄｙ,实验结果表明,Ｔｂ含量在０ａｔ％～０．８６％ａｔ％范围内,随着合金中Ｔｂ含量啬式样的Ｈｃｊ显著增加,αＢｒ则显著减小,Ｂｒ基本上没有变化。当Ｔｂ增加到０．８６ａｔ％时,Ｂｒ仍然     

Spectrofluorimetric determination of terbium with terephthalic acid

A spectrofluorimetric method has been developed for the determination of terbium(III) based on the formation ofa complex with terephthalic acid [benzene-1,4-dicarboxylic acid (TPA)] in slighdy acidic aqueous solution in the presenceof gelatin. Terbium ion can form a stable complex with TPA with the stoichiometry of 1:2. The best excitation and maxi-mum emission wavelengths are observed at 260 nm and 545 nm, respectively. The fluorescence intensity of terbium com-plex gets the strongest within 20 min and remains stable up to 10 h, and it is proportional to terbium(III) concentration in therange of 4.0×10-5-1.6×10-7 mol·L-1 under the optimum conditions. The fluorescence system has good selectivity, sensitivityand stability. The relative standard deviation is still within ±4% in the presence of 1200-fold amounts of the other lanthanideions when the concentration of terbium(III) is 1.0×10-6 mol·L-1 and common co-existing ions hardly interfere the determi-nation. It has been applied to the direct fiuori     

Syntheses, characteristics and fluorescence properties of complexes of terbium with benzoic acid and its derivatives

The binary complexes of terbium with benzoic acid and its derivatives (phthalic acid, iso-phthalic acid, oaminobenzoic acid, salicylic acid, sulfosalicylic acid) were synthesized and their compositions were identified by elemental analyses. UV, IR of the complexes were investigated. The UV spectra indicate that the complexes‘ ultraviolet absorption is mainly the ligands‘ absorption, but the location of peak drifts. The IR spectra show that the IR spectra of complexes are different from those of free ligands, and the band at 400 - 500 cm^-1 , due to the stretching vibration of Tb--O, is absent for free ligands. The fluorescence properties were investigated by using luminescence spectroscope, the results show that all the six complexes of terbium exhibit excellent luminescence, due to the transition from the lowest excited state ^5D4 to ^7F ground state manifold, the complexes of terbium with sulfosalicylic acid have the strongest fluorescence intensity, and is stronger than o-aminobenzoic acid-terbium, whose fluorescence intensity is regarded as the strongest one in the literature, and even stronger than some phosphor of terbium.     

由金属氧化物直接制备TbDyFe合金粉

一种TbDyFe合金粉末的制备方法，该方法采用金属钙作还原剂，直接由氧化物(Tb4O7、Dy2O3、Fe2O3)通过还原扩散法直接制得含铽为17．2％-17．5％，含镝42％(质量)的TbDyFe合金粉，与现有技术相比，本技术通过金属钙还原得到金属铽、镝并立即扩散与还原铁形成TbDyFe合金，该法无环境污染，生产成本低，合金中含铽、镝量稳定，可用于磁致伸缩材料。     

晶界扩散Dy合金对烧结NdFeB磁体磁性能的影响

采用晶界扩散工艺制备烧结NdFeB磁体。研究了不同渗材、不同扩散时间对烧结NdFeB磁体性能的影响,研究不同磨削量对扩散镝合金磁体性能的影响。结果表明,镝合金(Dy_(80)Fe_3Al_(10)Cu_4Ga_3)具有较低的熔点,在900℃扩散温度下呈液相,其扩散速度大于氟化物的固相扩散速度。900℃保温5h,晶界扩散镝合金,取向5mm厚N52磁体的矫顽力提升46.28%。距离磁体表面70μm以内可以检测出较高的镝含量,说明在磁体表面存在较薄的高镝浓度区域,该区域磁体具有较高矫顽力,距离表面100μm以外直至磁体芯部,镝含量分布均匀,矫顽力趋于一致。     

Thermal decomposition kinetics and lifetime of the complex of Tb2（BA）6（PHEN）2

The thermal behavior of Tb2(BA)6(PHEN)2 (BA: benzoate, and PHEN: 1,10-phenanthroline) in a static air atmospbere was investigated by TG-DTG, SEM and IR techniques. By the kinetic method of processing thermal analysis data put forward by Malek et al., it is defined that the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energy E for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS^≠ is -84.72 J/mol, the enthalpy of activation ΔH^≠ is 94.26 kJ/mol, the free energy of activation ΔG^≠ is 144.77 kJ/mol and the pre-exponential factor lnA is 20.93.The lifetime equation at mass-loss of 10% was deduced as lnτ = -29.0312 19760.83/T by isothermal thermogravimetric analysis.     

元素Tb对(Fe,Co)-B-Si-Nb块体非晶形成及磁性能的影响

用铜模吸铸工艺制备了[(Fe0.5Co0.5)0.72B0.192Si0.048 Nb0.04]100-xTbx和[(FeyCo1-y)0.72B0.192Si0.048Nb0.04]98Tb2块体非晶合金,并用XRD、DSC、振动样品磁强计(VSM)测试和分析了微量稀土元素Tb和不同Fe与Co比例对(Fe,Co)-B-Si-Nh体系玻璃形成能力、热稳定性及软磁性能的影响.试验表明,添加2 at%的Tb,提高了合金的非晶热稳定性和形成能力,制得的非晶合金棒的直径从φ2mm增加到φ3 mm,但饱和磁化强度下降;[(FeyCo1-y)0.72B0.192Si0.048Nb0.04]98Tb2合金随Fe与co比例从5:5增加至7:3时,合金的非晶形成能力呈下降趋势,但均能形成直径为φ2 mm的非晶棒,而其热稳定性和饱和磁化强度随铁含量的增大而提高.     

Thermal stability and luminescence properties of 1,10-phenanthroline-tris （m-methylbenzoate） europium （or terbium） complexes in SiO2 gel

Silica gel luminophors containing 1, l O-phenanthroline-tris(m-methylbenzoate) europium (or terbium) complexes were prepared by sol-gel method. The thermal decomposition, excitation and emission spectra for the gel phosphors were measured and compared with that of solid complex powders. The thermal stability of the complexes was enhanced in SiO2 host matrix and the luminescence intensity remained unchanged.     

CaCl2熔盐中直接电化学还原制备铽-镝-铁合金机制

CaCl2熔盐为电解质,石墨棒作辅助电极、铂片作参比电极,以定组成Tb2O3、Dy2O3、Fe2O3(1:1:2)均匀混合氧化物粉体制成工作电极,利用循环伏安法和计时电流法对电化学还原制备铽-镝-铁合金的过程进行研究,并以石墨棒为阳极,混合氧化物烧结片为阴极,采用恒电位电解法对电化学测试结果进行检验并利用XRD分析电解产物的组成。结果表明,CaCl2熔盐中电化学还原可以制备出铽-镝-铁合金;混合氧化物电化学还原制备铽镝铁合金是不可逆过程,合金生成按照Fe、DyFe5、TbFe3、DyFe2和TbFe2的先后顺序5步完成;电化学还原过程是在Fe|Fe2O3|CaCl2、Tb-Dy-Fe|Tb2O3-Dy2O3|CaCl2两个三相界线上先后进行。     

Fluorescence enhancement and cofluorescence in complexes of terbium（Ⅲ） with trimellitic acid

The fluorescence of terbium (III) was enhanced by about three orders of magnitude in the presence of trimellitic acid (benzene-1, 2, 4-tricarboxylic acid (TLA)) in aqueous solution at pH 6. The fluorescence intensity could be greatly increased when the system of Tb³⁺-TLA was treated with La³⁺(or Gd³⁺) and TritonX-100. The addition of La³⁺(or Gd³⁺⁾ enhances the fluorescence of the system by about two orders of magnitude due to cofluorescence, and the TritonX-100 micellar medium plays an important role for stabilization of the system. Both the intermolecular energy transfer mode and intramolecular energy transfer mode are responsible for the mechanism of fluorescence enhancement. In the optimum conditions, the fluorescence intensity is a linear function of Tb³⁺ concentration in the range of 7.8 × 10⁻⁹-3.6 × 10⁻⁶ mol/L for the system Tb³⁺-La³⁺-TLA and 1.0 × 10⁻⁸-4.7 × 10⁻⁶ mol/L for the system Tb³⁺-Gd³⁺-TLA, and the limits of detection are 4.6 × 10⁻¹⁰ mol/L and 6.0 × 10⁻¹⁰ mol/L, respectively.     

一种新的铽发光配合物的合成、晶体结构及表征

在水热合成条件下合成一个新的吡啶-3,5-二羧酸的稀土铽配合物[Tb2(pydc-3,5)3(H2O)9]n3nH2O,通过X射线单晶衍射、元素分析和红外等手段的表征确定该化合物的组成和晶体结构。结果表明,吡啶-3,5-二羧酸(pydc-3,5)配体与稀土金属Tb形成了一维链状配位聚合物,中心稀土金属有两种配位形式,每个金属均与氧原子形成九配位的结构。配体中的羧酸根采用两种配位方式,即单齿配位和双齿配位。同时配合物能发出三价铽离子的特征绿色荧光,荧光光谱的研究表明,配合物表现出很好的荧光性能。     

Crystal structure and properties of terbium o-methylbenzoate complex with 1,10-phenanthroline [Tb（o-CH3C6H4COO）3（C12H8N2）]2

A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen (where o-MBA =o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solution and its crystal structure was deter-mined by X-ray diffraction. The crystal of the complex Tb(o-MBA)_3phen belongs to triclinic crystal system and P 1 (#2)space group. The crystal data are as follows: a=1.4371(4)nm, b=1.7387(2)nm, c=1.3109(2)nm, α=96.37(1)°,β=107.21(2)°, γ=82.78(2)°, V=3.094(1)nm~3, Z=2, M_r=1489.12, D_c=1.598g·cm, μ=2.330mm~(-1) and F(000)=1488.00.The final R and R_w are 0.038 and 0.047 for 8668Π>2σ(Ⅰ)] unique reflections, respectively. In the complex each Tb~(3 ) ion iseight-coordinated by one 1,10-phenanthroline molecule, one bidentate carboxytate group and four bridging carboxylategroups. The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and the bridging biden-tate. Excitation and luminescence data observed at room temperature show that the title complex emits     

Fluorescence and preparation of Sr2（P2O7）：Ce,Tb phosphate by co-precipitation method

The micron-sized Sr2（P2OT）：Ce,Tb green phosphors were prepared by being annealed at different temperatures with its precursors synthesized by co-pre-cipitates of （NH4）2HPO4 at ambient temperature. The phase structure, grain size, surface morphology, and luminescent properties of phosphors were investigated by X-ray diffraction, scanning electron microscope, trans-mission electron microscope, and fluorescence spectrum. The results show that the product of precursor annealed at 1,100 ℃ is Sr2（P2O7）：Ce,Tb, which belongs to ortho-rhombic phase. The powder is spherical and the size dis-tribution is in micron grade. The sample with the molar ratio of Sr/Tb/Ce of 100.0：0.4：0.6 shows the best fluores-cence effect annealed at 1,100 ℃ for 3 h. The phosphors produce green fluorescence by being excitated with ultra-violet radiation of 254 nm wavelength, and the main emission peak is at 547 nm. The Sr2（P2O7）：Ce,Tb phos-phors synthesized by co-precipitation method of precursors at ambient temperature is a kind of efficient green-emitting phosphors.