Photon Cascade Emission through Energy Transfer in Pr^3＋and Er^3＋Codoped System

Energy transfer processes in Pr^3 -codoped CaAl12O19crystal from 12 to 290K were studied.Energy transfer from Pr^3 toEr^3 ions in this system was observed,The transfer can partially convert the ^1S0UVfluorescence of Pr^3 into green emission of the characteristic of Er^3 ,The efficiency of the energy transfer was estimated based of the spectroscopic data,The temperature dependence on the transfer was also discussed.     

Temperature-Dependent Emission of Pr^3＋ -Doped LaB3O6 under Vacuum Ultraviolet Excitation

The vacuum ultraviolet （VUV） luminescent properties of Pr^3＋ -activated LaB3O6 were investigated with highenergetic synchrotron radiation from 20 to 300 K. In the emission spectra, the parity-forbidden 4f^2→4f^2 and parity-allowed 4f5d→4f^2 transitions were observed simultaneously. In addition, it was also observed that the intensity of 4f5d→4f^2 emission bands increased relative to the intensity of 4f^2→4f^2 emissions with increasing temperature. The thermal equilibrium model of energy levels was employed with respect to the lowest 4f5d state and ^1S0 state of LaB3O6：Pr^3＋ , as a result of which the fitted curve had a good agreement with the experiment values, which clarified the physical nature of temperature-dependent emission characteristics of Pr^3＋ in LaB3O6.     

Hydrothermal preparation and persistence characteristics of nanosized phosphor SrS：Eu^2＋,Dy^3＋

Nanosized long-persistent phosphors SrS: Eu2+, Dy3+ were prepared by the hydrothermal method. The samples were characterized by X-ray powder diffraction, transmission electron microscopy, and charge-coupled device spectrometry. The persistence characteristic was studied using the decay curves. The results showed that the emission intensity decreased sharply with temperature increasing, although the particle size increased. The S2- vacancies caused by oxidization served as shallow traps, and Dy3+ served as deep traps in SrS: Eu2+, Dy3+. The afterglow intensity of SrS: Eu2+, Dy3+ was higher than that of SrS: Eu2+ prepared at the same temperature. However, the minimization span of initial afterglow with temperature for the former sample was larger than that for the latter. Binary-doped phosphor decayed more slowly than the singly doped one. The afterglow of SrS: Eu2+, Dy3+ decayed more quickly with the increase of sintering temperature.     

多种支护型式联合应用在深基坑支护工程中

土钉墙、喷锚网、排桩、深井降水等技术是基坑支护工程常用的技术手段.通过在大面积深基坑支护工程中对多种支护型式的联合运用,根据工程地质条件、支护要求等,合理选择施工参数,在施工过程中,严格按规范操作,达到施工目的.对同类型的工程施工有一定的参考作用.     

ZnO:Eu3+纳米晶的制备及其光谱分析

制备了ZnO：Eu3 的纳米颗粒，得到粒径在5nm左右的纳米晶。通过光谱分析研究了不同浓度的掺杂对ZnO发光性质的影响，Eu掺杂可以提高纳米ZnO的发光充度及影响其粒径大小，并观察到了ZnO与Eu之间的能量传递。     

频域光存储和时域光存储

应用光谱烧孔和受激光子回波,在光存储材料中一个光斑面积上可以存储频率上或时间上编码的多个信息,使存储密度提高2-3个数量级.本文介绍这些方法的原理、目前研究的状况及前景。现在使用的光盘,存储密度约为4×10~7bit/cm~2.用激光使光盘上被照射区域的光学性质发生变化,写入值息;探测这种变化,通过信号的有无或强弱读出信息.高分辨激光光谱学的发展为在一个光斑面积内存储多个信息,从而进一步提高存储密度提供了可能.一个光斑内存储的信息如果是在频率上编码的,称为频域光存储;如果是在时间上编码的则称为时域光存储.本文介绍频域和时域光存储的原理、现状和前景。     

控制爆破拆除厂房内钢筋砼基础

介绍了特殊环境里的钢筋砼设备基础的控制爆破拆除技术,对在爆破工程业务中如何运用控制爆破定额提出了一些看法.     

SiO_2凝胶玻璃中Eu~(3+)、Tb~(3+)与1,10-邻菲罗啉配合物的原位化学合成及其荧光和热学性能

应用原位化学复合方法，将Eu3＋、Tb3十与1；10-邻菲罗啉配合物光学均匀复合到SiO2凝胶玻璃中，解决了因稀土含氮配合物易水解而难以用溶胶-凝胶工艺将其均匀掺入无机基质的问题研究了原位配合物的荧光和热学性能结果表明，由于配合物的形成使稀土离子特征荧光强度显著增加，而无机基质的保护作用则使原位配合物的热稳性提高200℃以上化学合成纯配合物Eu（Phen）2Cl3·2H2O的高分辨荧光谱表明，Eu3+在其中的格位对称性为C1或C2或C3．     

Er3+掺杂的MFT玻璃材料2H11/2、4S3/2→4I15/2荧光性质

计算了Er^3 掺杂的氟氧化物玻璃材料MFT的J－O参数,进而获得了一些能级间跃迁的跃迁几率、分支比、及寿命等数据,测量了室温下Er^3 的较强的两个绿色发射^2H11／2、^4S3／2→^4I15／2及红色发射^4F9／2→^4I15／2的激发光谱,观测了^2H11／2、^4S2／2→^4I15/2跃迁荧光强度随着温度的变化,测量了室温下这两筹这衰减曲线,计算了这两个能级的无辐射跃迁几率及量子效率。     

用非相干光时间延迟四波混频研究Cu_2O超微粒子的载流子复合时间和扩散系数

报道了用非相干光时间延迟四波混频方法在室温下测得Ｃｕ２Ｏ超微粒子的扩散系数和载流子复合时间分别为０．０１１ｃｍ２／ｓ和１．２ｎｓ。通过改变探测光与前向泵浦光之间的夹角实验和变温实验证实了这种方法的正确性。并讨论了扩散机理。