溶胶-凝胶法制备Y2Zr2O7∶Tm3+及其发光性能研究

以柠檬酸为络合剂采用溶胶-凝胶法制备了（Y1-xTmx）2Zr2O7（x=0.005,0.01,0.03,0.05）荧光粉.采用X-射线衍射分析仪（XRD）、扫描电子显微镜（SEM）和荧光光谱仪分别检测了Y2Zr2O7∶Tm3+的晶体结构、颗粒形貌以及样品的荧光光谱.XRD图谱表明,所得到的产物Y2Zr2O7∶Tm3+为单一相的萤石结构,而且Tm3+的掺杂并没有改变其晶体结构.荧光光谱的测试表明,在359 nm波长的紫外光激发下,1000℃下烧结的（Y1-xTmx）2Zr2O7（x=0.01）样品的发光性能最好,发射峰对应于Tm3+的1D2→3F4跃迁和1G4→3H6跃迁,并对其发光机理进行了探讨.样品在454 nm处的发光强度随Tm3+离子掺杂浓度的增加先升高后降低,即出现了浓度猝灭的现象,当Tm3+掺杂浓度摩尔百分比为1%时,样品的发光强度达到最大.     

低温条件下光学厚度对Tm3+：YAG材料光谱烧孔孔深的影响

通过理论与实验研究了光学厚度对Tm3+：YAG材料光谱烧孔孔深的影响。提出了一种用于分析光学厚度对光谱烧孔孔深影响的新模型。该模型从理论上推导了烧孔孔深与光学厚度的关系。根据提出的理论模型,当温度大于4K时,通过选择合适的光学厚度可以使光谱烧孔孔深得到最大值。最后通过使用合适的激光与Tm3+：YAG材料所形成的光谱烧孔实验证明了实验结果与理论分析是相一致的。     

Tm,Ho声光调Q激光系统理论与实验研究

利用激光速率方程理论,对Tm,Ho激光系统计算预测得出最佳耦合输出透过率和调Q激光脉冲宽度.实验采用Tm, Ho:LuLF为增益介质,三向侧面泵浦,环形腔声光调Q.选用透过率20%和30%的输出镜作对比.在透过率20%耦合输出时,得到调Q激光脉冲能量最大为58.0 mJ,对应光光转换效率为1.45%;在透过率30%耦合输出时,得到调Q激光脉冲能量最大为62.9 mJ,对应光光转换效率1.57%,并且获得了最大动静比48.7%.激光脉冲宽度在注入能量3.25 J时为417.2 ns.与理论计算结果较为一致.     

Effect of heat treatment on crystal phase and photocatalytic activity of Tm doped TiO2 nanoparticles

Abstract

Abstract

Tm doped TiO₂ nanoparticles have been synthesised by hydrolysis-precipitation method. The effect of heat treatment on the crystal phase and photocatalytic activity of Tm doped TiO₂ nanoparticles has been studied. The prepared samples were characterised by transmission electron microscopy, X-ray diffraction, Fourier transformed infrared and diffuse reflection spectrum analysis. The results show that Tm³⁺ doping can effectively inhibit the phase transformation from antase to rutile and decrease the crystallite size of nano-TiO₂ particles. There is an optimal Tm doping (1·4?mol.-%) after calcination at 550°C for the photocatalytic activity of methylene blue degradation.     

INTERFACIAL ADSORPTION OF 2-HYDROXY-5-NONYLBENZOPHENONE OXIME IN STATIC AND VIGOROUSLY STIRRED DISTRIBUTION SYSTEMS

ABSTRACT

The interfacial adsorption of 2-hydroxy-5-nonylbenzo-phenone oxime (LIX65N) at a n-heptane/water interphase was examined under static and vigorously stirred conditions, varying the aqueous pH from 2 to 12. In static systems, the pH and the concentration dependences of the interfacial tension were analysed on the basis of the Gibbs equation. The acid dissociation equilibrium at the interface was evaluated. In vigorously stirred systems, the interfacial adsorption was observed as a reversible, reproducible decrease of the organic phase concentration in response to stirring. A Langmuir isotherm was applicable for the adsorption of neutral LIX65N in acidic condition. The greater adsorption of the anionic form of LIX65N occurring in alkaline condition required an alternative isotherm.     

Yb3+-Tm3+共掺BiOBr纳米晶的近红外上转换发光特性研究

采用水热法合成了Yb³⁺-Tm³⁺共掺BiOBr纳米晶, 研究了其上转换发光性能。在980 nm光激发下, 样品中Tm³⁺离子实现了³H₄→³H₆、¹G₄→³F₄和¹G₄→³H₆跃迁, 进而发出强烈的近红外光(801 nm)和较弱的红光(655 nm)与蓝光(485 nm)。探讨了样品的上转换发光机理, 上转换发光强度与激发功率的关系表明在980 nm激发下Tm³⁺的蓝光和红光发射为三光子过程, 而近红外发光为双光子过程。随着Yb³⁺浓度增加, 近红外发光显著增强, 近红外光与蓝光(I_{801 nm}/I_{485 nm})的发光强度比高达71.4。研究结果表明, Yb³⁺-Tm³⁺共掺BiOBr纳米晶在生物荧光标记领域具有潜在的应用前景。     

2 μm掺铥光纤激光研究进展及其应用

掺铥光纤激光器输出的2 μm波段在医疗、激光雷达、遥感测控和光参量振荡方面有着广泛应用,目前已实现千瓦级的激光输出。文中主要介绍了掺铥光纤激光器的基本结构及工作原理,并综述和分析了国内外掺铥光纤激光器的研究进展,并展望了掺铥光纤激光器的发展。     

应用Power Perfecter实现DCS的锅炉优化控制

介绍了Max1000 DCS系统和Power Perfecter锅炉优化控制技术;针对锅炉现有主要监测参数,提出了对炉膛负压、送风量、氧量、煤量等过程变量的优化控制方案;通过分析网络数据交换的特点,对优化控制系统安装后系统的安全性进行了论证。     

多路Cr,Tm,Ho:YAG激光器合光路的设计

在介绍国外四路Cr,Tm,Ho:YAG激光器的基础上,提出了三种四路Cr,Tm,Ho:YAG激光器合光路经光纤输出的方案,并进行了比较,最终确定了基于平面的四路Cr,Tm,Ho:YAG激光器合光路设计方案。在三路情况下,当单脉冲最大注入能量为100J,重频30Hz时,激光器直接输出功率50.17W,光纤末端输出功率35.65W,耦合效率为71%。经文献调研,目前所达到的输出功率处于国内领先水平。     

掺Tm3+光纤激光器的进展

总结分析了近期连续波输出、脉冲输出和上转换连续波输出的掺，Tm^3 光纤激光器现状。指出采用Tm^3 分别与Yb^3 、Ho^3 和Al^3 共掺的光纤，可使掺Tm^3 光纤激光器扩展抽运源波长、压缩调Q脉宽和提高斜率效率。