Effect of an electric field on the transport of Th(IV) in the presence of Eu(III) and U(VI) through supported liquid membrane containing di‐2‐ethylhexylphosphoric acid

This paper investigates the transport of Th(IV) ions in nitric acid media through a supported liquid membrane (SLM) impregnated with di‐2‐ethylhexylphosphoric acid (HDEHP) in kerosene using an electric field. The transport was carried out in a three compartment cell fitted with microporous cellulose nitrate (SLM) and cation exchange membrane (Nafion). The effect of different parameters including nitric acid concentration in the feed solution, HDEHP concentration in the membrane, and HCl concentration were studied. The optimal conditions for Th(IV) transport were 0.1 mol dm^?3 HDEHP, 10^?3 mol dm^?3 HNO₃ in the feed solution, 1 mol dm^?3 HCl in compartment 2 and 1 mol dm^?3 HCl in compartment 3 at 25 °C. Under the optimal conditions of Th(IV) transport the recovery factor after 90 min was 0.25 without applying an electrostatic field, compared with 0.9 when the electric field was applied. The effect of electric current on the flux of Th(IV) through the membrane was also studied. The flux increased as the current density increased from 10 to 30 mA cm^?2 to reach a maximum value at 30 mA cm^?2 (8 × 10^?9 g eq cm^?2 s^?1). The transport percentages of 0.3 g dm^?3 Th(IV) in the presence of 0.1 g dm^?3 Eu(III) and 1 g dm^?3 U(VI) were 66, 84 and 15%, respectively. The determined selectivities of U(VI)–Th(IV) and Th(IV)–Eu(III) were 0.12 and 0.3, respectively, after 90 min. Therefore, the order of selectivity of this system is Eu(III) > Th(IV) > U(VI). © 2001 Society of Chemical Industry     

Characterization of Photoluminescent (Y1–xEux)2O3 Thin Films Prepared by Metallorganic Chemical Vapor Deposition

The purpose of this study was to identify and correlate the microstructural and luminescence properties of europium-doped Y₂O₃ (Y_{1– x} Eu _x )₂O₃ thin films deposited by metallorganic chemical vapor deposition (MOCVD), as a function of deposition time and temperature. The influence of deposition parameters on the crystallite size and microstructural morphology were examined, as well as the influence of these parameters on the photoluminescence emission spectra. (Y_{1– x} Eu _x )₂O₃ thin films were deposited onto (111) silicon and (001) sapphire substrates by MOCVD. The films were grown by reacting yttrium and europium tris(2,2,6,6-tetramethyl–3,5-heptanedionate) precursors with an oxygen atmosphere at low pressures (5 torr (1.7 × 10³ Pa)) and low substrate temperatures (500°–700°C). The films deposited at 500°C were smooth and composed of nanocrystalline regions of cubic Y₂O₃, grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600°C developed, with increasing deposition time, from a flat, nanocrystalline morphology into a platelike growth morphology with [111] orientation. Monoclinic (Y_{1– x} Eu _x )₂O₃ was observed in the photoluminescence emission spectra for all deposition temperatures. The increase in photoluminescence emission intensity with increasing postdeposition annealing temperature was attributed to the surface/grain boundary area-reduction effect.     

固溶体Ce1-xEuxO2-δ的导电性能

利用溶胶-凝胶法,经800℃焙烧10h合成了Ce1-xEuxO2-δ(x=0.05～0.50)固溶体.用X射线衍射仪检测了样品的结构,测量了样品的阻抗谱和电子顺磁共振谱.结果表明:当掺杂量x≤0.40时,固溶体的结构为单相立方萤石结构,晶胞参数随x的增加而增大.样品中存在Ce3 ,掺杂Eu3 可以抑制Ce4 离子的还原.通过掺杂使固溶体Ce1-xEuxO2-δ(x=0.10～0.40)的电导率提高,随着掺杂量x增加,电导率增大,并在x=0.20时达到最大值(500℃的电导率σ500℃=1.07×103S/cm);电导活化能减小,x=0.20时,电导活化能Ea达到最小值,为0.72eV.     

新荧光试剂5－（4＇－硝基－2＇－羧基苯基偶氮）－2－硫代－4－噻唑啉酮的合成及其应用研究

报道了５－（４＇－硝基－２＇－羧基苯基偶氮）－２－硫代－４－噻唑啉酮（４ＮＲＡＣＰ）的合成。经柱层析提纯，用元素分析、ＩＲ、１ＨＮＭＲ和ＭＳ确证了其结构，研究了荧光性质，发现该试剂在溴代十六烷吡啶存在下，在无水乙醇溶液中与Ｅｕ（Ⅲ）形成稳定的荧光螯合物，λｅｘ／λｅｍ＝２９０ｎｍ／３４０ｎｍ，其线性范围为１．０×１０－８～１．０×１０－６ｍｏｌ·Ｌ－１，检测限为１．５×１０－１０ｍｏｌ·Ｌ－１。测定了人工合成样品中的铕，结果满意。     

用BPhen作基质的铕配合物OLED发光机制研究

用具有良好电子传输/空穴阻挡性能的BPhen(4,7-diphenyl-1,10-phenanthroline)作基质,Eu(DBM)3pyzphen(pyzphen=pyrazino-[2,3-f][1,10]-phenanthroline,DBM=Dibenzoylmethane)作发射材料,成功制得了高效率、高亮度的有机电致发光器件OLED.器件的最大外量子效率为2.5%,最大电流效率为5.3 cd/A,最大亮度为1 320 cd/m2.在亮度为200和1 000 cd/m2时,器件的色坐标分别为(0.66,0.33)和(0.65,0.34).深入研究了该器件的发光机制,发现在电致发光(EL)过程中,载流子直接被Eu(DBM)3pyzphen陷获是主要的发光机制,同时在BPhen与Eu(DBM)3pyzphen间还存在着有效的能量传递.     

溶胶-凝胶法制备的BaMgAl10O17:Eu前驱体的晶化过程

采用柠檬酸作为螯合物的溶胶-凝胶法制备了BaMgAl10O17：Eu(barium magnesium aluminate,BAM)蓝色荧光粉,并研究了,其晶化过程。通过X射线衍射、扫描电镜和荧光光谱等表征手段,研究了前驱体晶化过程的焙烧条件、结晶动力学、颗粒大小和发光性能等。BAM晶相在1100℃开始产生。温度达1200℃时,前驱体由无定型态完全转变成BAM晶相。在1120～1300℃时晶化反应的表观活化能为233kJ／mol。在室温下测得荧光粉的最大吸收峰和发射峰分别处在334nm和454nm。合成荧光粉的粒径为5μm左右,其形态和粒径取决于前驱体。     

模板导向低温合成固体发光材料Y2O3:Eu3+、Am+、Bn+的研究

本文采用模板导向的方法,添加合适模板剂降低灼烧温度,合成橙红色荧光体。研究离子掺杂的荧光体Y2O3：Eu^3 A^m 、B^n 的荧光性质。发射光谱数据表明：杂质离子掺杂的荧光体Y2O3：Eu^3 A^m 、B^n 的荧光发射主峰与荧光体Y2O3：Eu^3 的荧光发射主峰(612nm)一致,为经典Eu^3 的^3D0-^7F2电偶极跃迁;杂质离子的引入明显地增强了Y2O3：Eu^3 的发光强度,并且有短时间余晖存在。     

Intracellular behaviour of samarium and europium in lactating mammary gland

The subcellular localization of samarium and europium, two rare-earths, increasingly used in both medical and industrial fields, has been studied in several organs such as liver and kidney but never in the mammary gland despite of its importance in the biology of lactation and nutrition domains. The intracellular behaviour of samarium and europium after their intra-peritoneal administration in the lactating mammary gland cells was investigated. The results showed the presence of very electron dense deposits in the glandular epithelial cell lysosomes. These particular lysosomes were never observed in the mammary cell lysosomes of control rats. These intralysosomal deposits were probably composed of insoluble samarium or europium phosphates by analogy with previous studies, the transmission electron microscopy, the ion mass microscopy and the electron probe microanalysis, and other techniques allowing the identification of the chemical structure of the intralysosomal deposits.     

Facile synthesis of visible light excited La_1-xGd_xF₃:Eu³⁺ micro-meter sphere using polyvinylpyrrolidone as a template

Lanthanide fluorides exhibited unique luminescent properties in terms of their low phonon energy can restrict the luminescence quenching and extend luminescent lifetimes.Here,a room-temperature co-precipitation method was used to synthesize europium(III) activated La1-xGdxF3 solid phosphors.X-ray diffraction(XRD) data confirmed the crystalline phases of synthesized sample belongs to orthorhombic system.All the as-derived materials exhibited red luminescence(5D0→7F1) under the excitation at longer wavelengths(394 and 466 nm).The powder with the most intense emission was achieved in terms of 10 mol.% doping concentration(Eu content,La/Gd=1/9) and sample sintered at 700 oC.Scanning electron microscopy(SEM) investigated the morphology and crystalline of the samples,showing that many regular and large balls(5-10 μmol/L) were dispersed within the micro-meter scale composites.We proved that the above crystal growth structures were controllable and predicable based on the surface functionalization by polyvinylpyrrolidone ligand.     

Photophysical properties of a new ternary europium complex with 2-thenoyltrifluoroacetone and 5-nitro-1,10-phenanthroline

A ligand, 5-nitro-1,10-phenanthroline (phenNO2), was synthesized. Its Eu(III) complex with 2-thenoyltrifluoroacetone (HTTA) was prepared and characterized by elemental analysis, IR and 1H NMR spectra. The photophysical properties of the complex were studied in detail by using UV, luminescence spectra, luminescence lifetime and quantum yield. The complex exhibited nearly monochromatic red emission at 612 nm, a remarkable luminescence quantum yield at room temperature (36.0%) upon ligand excitation and a long 5D0 lifetime (458 μs), which indicated that the ligand phenNO2 could sensitize the luminescence of Eu(III) ion efficiently.