Structural Dependence of Magnetic and Transport Properties in Doped Manganite Perovskites

1 INTRODUCTION In recent years, ABO3-type perovskite-like manganites, RE1xDxMnO3 (RE = rare earth ions, D = Ca2+, Sr2+, Ba2+ etc.), have inspired remarkable attention due to the colossal magnetoresistance (CMR) effects for fundamental and practical consideration [1, 2]. Since A- and B-site substitution can give rise to a large number of derivant compounds, fruitful structural, magnetic and transport properties would be expected in this family. As we have known, the ideal ABO3-typ…     

Y2O2S：Eu,Mg,Ti,Tb红色长时发光材料的研究

利用高温固相反应法合成了一种新型的红色长时发光材料－Y2O2S：Eu,Mg,Ti,Tb.材料的XRD测试结果表明Eu掺杂引起Y2O2S，Eu,Mg,Ti,Tb晶胞增大，激发光谱，发射光谱和发光衰减曲线表明该材料是一种适合紫外线和可见光激发，并具有很好的长时发光性能的红色长时发光材料，热释光谱测试结果表明该材料可能具有两个较深的陷阱能级，研究了Eu,Mg,Ti,Tb的加入量对材料发光特性的影响。结果表明：Eu,Mg,Ti,Tb影响材料的初始亮度和发光时间，Eu决定材料的红色比。     

稀土聚乙炔电池及其电化学

聚乙炔作为合成的有机金属具有极大的应用潜力。MacDiarmid等发现可用电化学方法对聚乙炔进行可逆掺杂,使其电导率达到金属的水平,而且聚乙炔本身具有一个由微纤维组成的网状结构,有很大的表面积(～60m~2/g),因此适合于作二次电池的电极。人们已在实验室制备了各种类型的聚乙炔电池,它们具有重量轻、能量密度高、功率密度大、可充电等特点,因而具有研究价值。沈之荃等曾应用稀土配合催化剂合成了高含量顺式的、热稳定性较高的和抗氧化稳定性的聚乙炔。本文报道稀土聚乙炔电池及其电化学的研究工作。结果表明:稀土聚乙炔电池的开路电压可达3.5V,短路电流达10mA,平均功率密度达160W/kg,具有进一步开发研究的前景。     

Sm2O3掺杂CeO2纳米粉体的烧结动力学

对Sm2O3掺杂CeO2纳米粉体的烧结性能进行了研究, 得出等速烧结过程中试样的线收缩率、密度、气孔率随烧结温度的变化规律, 它们随烧结温度的变化均呈"S"型曲线关系, 利用非线性回归了等速烧结过程动力学方程. 结果表明, Sm2O3掺杂CeO2纳米粉体的烧结过程分为3个阶段, 当烧结温度低于1000 ℃时, 线收缩率与密度变化较小, 处于烧结的初期; 在1000～1400 ℃时, 随着烧结温度的升高, 线收缩率与体积密度急剧增大, 材料开始烧结并致密化; 当烧结温度高于1400 ℃时, 线收缩率与体积密度趋于一恒定值, 材料已经致密化. 由归一化速率方程可知, 在T=1225 ℃时, 材料的烧结致密化速率最大.     

Electrospun nanofibers of poly（vinyl pyrrolidone）/Eu^3＋ and its photoluminescence properties

Nanofibers of poly（vinyl pyrrolidone） （PVP）/Eu^3＋ with diameters of 300-900 nm were prepared by using sol-gel processing and electrospinning technique. The products were characterized by scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FT-IR）, and photoluminescence （PL）. The results indicated that, Eu^3＋ was successfully embedded in the onedimensional hybrid nanofibers, and the PVP/Eu^3＋ hybrid nanofibers had favorable photoluminescence properties.     

The preparation and fluorescence properties of europium nanoparticles

A new structured metallic nanomaterial of europium nanoparticle was prepared using tannic acid as the reductive agent,and nanoeuropium protein conjugates were synthesized by the method of lipoic acid modification on the surface of nanoparticle,which opens a new field of application of lanthanides in nanotechniques.Their properties were also characterized by UV-vis absorption spectroscopy,transmission electron microscopy (TEM),and fluorescence spectroscopy.The europium nanoparticle and its protein conjugates solution were stable and water-soluble.The fluorescence intensity of the composite europium nanoparticles was significantly increased in the presence of trace protein,and was linear proportional to the concentration of proteins under optimum conditions.According to this,a fluorimetric method for the determination of protein was developed in this paper.     

Cu掺杂对LaMnO3催化剂的结构和催化氧化性能的影响

采用非晶态多核配合的方法合成了La1-xCuxMnO3(x=0、0.05、0.1、0.2、0.3、0.4、0.5)系列催化剂, 并用X射线衍射(XRD)、透射电镜(TEM)、比表面测定仪(BET)等手段对催化剂的微观结构进行了表征. 研究了Cu掺杂对钙钛矿结构及其对CO催化氧化发光性能及催化氧化CO、CH4性能的影响规律. 结果表明, 当x≤0.1 时, Cu掺杂仍可形成单相的钙钛矿结构; 当x>0.1时, 过量掺杂的Cu以CuO杂相存在. Cu掺杂可改善La1-xCuxMnO3催化剂对CO和CH4的催化氧化活性. 经700 ℃焙烧3 h制备的La0.9Cu0.1MnO3催化剂具有最高CO催化氧化活性(T100%=170 ℃), 该结果与CO催化氧化发光结果一致.而La0.95Cu0.05MnO3催化剂对CH4的催化氧化活性最高(T95%=705 ℃).     

Y2O3—Nb2O5—B2O3：Eu^3—.Bi^3＋的磷光体的晶体结构与光…

采用常规固相反应于１２００℃下制备了具有褐钆铌矿结构的Ｙ２Ｏ３、Ｎｂ２Ｏ５．ｂ２ｏ３（ｙ０．９３Ｅｕ０．０７）２Ｏ３．Ｎｂ２ｏ５．Ｂ２Ｏ３和（×０。９１Ｅｕ０．０７Ｂｉ０．０２）２Ｏ３．Ｎｂ２Ｏ５．Ｂ２Ｏ３等磷光体，研究了它们的发光性质。结果表明，在２６８ｎｍ紫外光激发下，由于ＮｂＯ４基团于４１０ｎｍ处发生＾１Ｔ→＾１Ａ１跃迁，致使Ｙ２Ｏ５．Ｎｂ２Ｏ５．Ｂ２Ｏ３呈现更亮的紫外发射。体系中Ｂ２Ｏ３可     

一种新的单基双掺稀土三基色荧光粉SrB4O7：Eu,Tb体系光谱特征

一种新的单基双掺稀土三基色荧光粉ＳｒＢ_４Ｏ_７：Ｅｕ，Ｔｂ体系光谱特征高勇，石春山（中国科学院长春应用化学研究所稀土化学与物理开放实验室，１３００２２）硼酸盐荧光材料是近年来引人注目的一类光致发光材料，分别以Ｔｂ３＋，Ｅｕ２＋为激活剂可以得到高效的灯...