Enhancement of upconversion luminescence of YAlO3:Er3+ by Gd3+ doping

The upconversion luminescences of YAlO3:Er3+ phosphor co-doping with different Gd3+ concentrations are investigated under the excitation of 980- and 532-nm diode lasers. A near ultraviolet upconversion emission at 410 nm is observed in YAlO3 under 532-nm excitation. Moreover, the inactive Gd3+ ions can improve the upconversion intensity efficiently in a certain range of concentration. Under 980-nm excitation, the visible upconversion emissions at 546 and 646 nm are enhanced by about 10 and 8 times at the Gd3+ concentration of 40%, respectively. The upconversion emission at 410 nm under 532-nm excitation is also enhanced by 7 times. The substitution of Gd3+ ions for Y3+ sites changes the local symmetry of Er3+, leading to the improvement of upconversion efficiency.     

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中国兵器工业信息化的发展是基于当代中国兵器工业发展要求应运而生的,并顺应和依托于现阶段的信息化技术。文章通过阐述中国兵器工业信息化发展现状,提出发展过程中存在的问题,归纳总结整个行业的发展趋势,重点强调统一标准、搭建统一平台、集团信息化、系统整合集成、管理信息化、网络安全等方面。中国兵器工业信息化的核心,仍然是如何将整合的信息更加有效地利用,转化为实际的科研、生产力。     

“自动控制原理”多媒体教学的模糊综合评价

本文建立了"自动控制原理"课程多媒体教学效果的评价指标,应用层次分析法确定各指标的权重.采用模糊综合评价法对"自动控制原理"课程多媒体教学效果进行评价并对评价结果进行分析.模糊综合评价法能够将影响多媒体教学的诸多指标因素综合考虑,保证了评价的客观性和准确性,同时能够将需要改进的指标因素直观体现出来便于改进,从而进一步提高教学质量.     

一种地面驱动螺杆泵井工况诊断方法

随着地面驱动螺杆泵采油技术的推广应用,急需寻找一种方便直观判断油井工况的方法.根据螺杆泵工作特性,提出一种定性诊断工况方法,为合理调整螺杆泵工作参数提供科学依据.