CaBi2Ta2O9:Pr3+黄色荧光粉的制备与性能研究

采用高温固相反应法,制备了系列Pr3+掺杂的CaBi2Ta2O9(CBTO:Pr3+)Bi层状结构铁电氧化物(BLSFs)粉体。利用X射线衍射(XRD)、扫描电子显微镜(SEM)对样品的晶体结构和形貌进行了表征。利用积分球式分光光度计和荧光光谱仪对样品的光学性能进行了分析。XRD结果表明,所生成的样品均为CBTO纯相。样品的吸收和激发光谱表明,在449~500nm波长范围存在Pr3+的f-f跃迁吸收;样品的发射光谱由绿光(525~575nm)和红光(575~700nm)发射两部分组成,避免了白光LED中再吸收的问题。随着Pr3+掺杂浓度的增加,样品的发光强度先增强后减弱,当Pr3+的掺杂浓度为2mol%时发光强度最大。研究了Ca0.98Pr0.02Bi2Ta2O9的热稳定性,并通过计算得到其热猝灭激活能E=0.24eV。显色指数(CIE)色坐标图表明,所制备的样品可以被蓝光有效激发而发出黄光。研究结果表明,CBTO:Pr3+可以用于蓝光LED芯片激发用的黄色荧光粉。     

中国传统文化与运动员培养

本文运用文献资料法、逻辑分析法剖析了中国传统文化与运动员培养的契合性与相悖性,肯定了传统文化对运动员素质培养的积极性因素,指出了其不利于运动员全面发展的主要因素。     

基于P2P的小型无线传感器网络的研究

今后无线传感器网络之间的交互和通信技术将是一项关键的技术.在介绍传感器网络特点的基础上,详细阐述了传感器网络以P2P方式联网构建移动的小型P2P传感器网络这项具体应用,描述了这项应用中网关的体系结构,介绍了作为P2P框架结构之一的JXTA协议,以及基于JXTA的这项应用的实验平台,给出了JXTA在这种移动环境中的性能表现.     

高海拔矿山地下采选联合思路

阐述了在高海拔条件下,地下开采矿山的选矿工艺车间与采矿开拓系统一起建设,采用地下硐室群方式解决地表建厂困难问题,采用长距离管道输送原矿浆至选厂,解决外部汽车运输困难问题,保护当地生态环境,实现地下采矿、选矿、外部输送一体化模式.     

Luminescent performance of rare earths doped CaBi2Ta2O9 phosphor

A series of red-emitting phosphors of CaBi₂Ta₂O₉:Pr³⁺ and CaBi₂Ta₂O₉:Eu³⁺ were synthesized by the solid-state reaction method. The crystal structure and photoluminescence properties were investigated by X-ray diffraction (XRD) and photoluminescence spectra. The emission spectra showed that the red emission peaks were located at 622 nm for Pr³⁺ and 615 nm for Eu³⁺, respectively. The optimal doping concentrations for Ca_1?xBi₂Ta₂O₉:xPr³⁺ and Ca_1?yBi₂Ta₂O₉:yEu³⁺ were x=0.02 and y=0.15, respectively. The effect of fluxes (H₃BO₃, NH₄F, CaCl₂ and CaF₂) and charge compensations (Li₂CO₃, Na₂CO₃ and K₂CO₃) on luminescent properties were investigated in detail. It was found that the relative emission intensity of Ca_0.98Bi₂Ta₂O₉:0.02Pr³⁺ with 10 mol.% H₃BO₃ flux was about 2.9 times higher than that of the sample without flux. The relative emission intensity of Ca_0.7Bi₂Ta₂O₉:0.15Eu³⁺, 0.15K⁺ was about the 2.1 times higher than that of Ca_0.85Bi₂Ta₂O₉:0.15Eu³⁺.