Tb3+掺杂PbF2基氟氧微晶玻璃的发光性能

采用高温熔融法和热处理工艺制备出一种Tb3+掺杂的PbF2基玻璃和微晶玻璃。经XRD分析发现,微晶玻璃内析出了PbF2颗粒,微晶团聚体平均尺寸约为15～75μm。在378 nm紫外光和X射线激发下,掺Tb3+的微晶玻璃与未经热处理的玻璃样品比较,微晶玻璃的发光强度增加了数倍,因而提出PbF2微晶的析出是微晶玻璃发光增强的主要原因。     

含Cr3+透明微晶玻璃的发光性能

选择若干玻璃组成，制得了含莫来石晶相的透明微晶玻璃，利用吸收光谱和室温荧光光谱对玻璃和微晶玻璃的发光进行了研究。研究表明，在一定测试范围内提高玻璃的晶化温度可以提高Cr^3 离子的有效发光效率；Cr^3 离子浓度的增加使微晶玻璃的发光强度增加，但引起浓度淬灭，降低Cr^3 离子的有效发光效率。对微晶玻璃荧光光谱中688nm发射肩的成因进行了探讨，提出了微晶玻璃荧光光谱中688nm和700nm发射可能由^2E能级分裂引起的观点。     

Ce~(3+)掺杂LiLuF_4氟氧微晶玻璃的发光性质

通过熔融法以及热处理,制备了Ce~(3+)掺杂含Li Lu F_4纳米晶的透明氟氧微晶玻璃。XRD结果表明,玻璃中析出的晶相为Li Lu F_4,其晶粒大小随热处理温度的升高和时间的延长而变大。在330 nm紫外光激发下,Ce~(3+)掺杂的氟氧玻璃和Li Lu F4微晶玻璃的发射为一峰值波长为370 nm的宽带光谱。微晶玻璃的发光强度显著高于未经过热处理的基础玻璃,并且随着热处理温度的升高及时间的延长,微晶玻璃的发光逐渐增强。微晶玻璃的370 nm发射的荧光寿命均长于基础玻璃的。     

基于灰度及几何特征的微晶玻璃缺陷检测

气泡缺陷检测作为评估微晶玻璃材料性能的重要环节,可指导微晶玻璃原坯切割与再加工,充分发挥其稳定的光学特性.针对环形光源照射微晶玻璃圆柱试样时,视场背景亮度不均匀且微晶玻璃外周边界被增亮的问题,提出了一种基于灰度及几何特征的微晶玻璃气泡检测算法.算法先根据图像局部灰度特征利用Canny边缘检测算子获取疑似气泡轮廓,再基于...     

硫系发光微晶玻璃研究进展

回顾了近年来关于稀土或过渡金属离子掺杂的硫系发光微晶玻璃的研究进展.深入讨论了稀土离子在硫系微晶玻璃中的微观分布对其发光性能的影响,以及不同稀土离子与晶体场之间相互作用的机制.总结和分析了近两年提出的一种新型硫系微晶玻璃——过渡金属离子激活的硫系微晶玻璃.通过可控晶化和晶体场调控,已经在硫系微晶玻璃实现了较强的Cr2+:1.8～2.8μm以及Co2+:2.5～4.5μm中红外超宽带输出.梳理了影响和制约硫系微晶玻璃在中红外光子器件功能化方面的关键问题,为今后此类研究提供一种思路.     

微晶结构对氟氧化物玻璃陶瓷发光特性的影响

制备了成分相同的Er3+/Yb3+共掺氟氧化物玻璃和氟氧化物玻璃陶瓷样品，x射线衍射谱和荧光光谱表明热处理后玻璃陶瓷中形成了纳米结构的微晶，根据Judd Ofelt理论计算和差热曲线分析，证实稀土离子掺入PbF2微晶中.分别计算了热处理前后微晶态部分在玻璃体中所占的比例. 关键词： 微晶结构 玻璃陶瓷 荧光光谱     

Tb3+掺杂透明锗酸盐微晶玻璃:制备与面向X射线探测的增强发光

通过熔融淬火和后续热处理,成功制备了Tb3+掺杂含LaF3纳米晶透明锗酸盐微晶玻璃.详细研究了所制备的玻璃和微晶玻璃的发光性质.X射线衍射结果表明,玻璃基体中析出的晶相为纯LaF3晶体,晶粒尺寸在16～21 nm之间.在377 nm紫外光和X射线激发下,Tb3+掺杂含LaF3纳米晶的微晶玻璃比Tb3+掺杂的锗酸盐玻璃表...     

Tb~(3+)掺杂透明锗酸盐微晶玻璃：制备与面向X射线探测的增强发光（英文）

通过熔融淬火和后续热处理,成功制备了Tb~(3+)掺杂含LaF_3纳米晶透明锗酸盐微晶玻璃。详细研究了所制备的玻璃和微晶玻璃的发光性质。X射线衍射结果表明,玻璃基体中析出的晶相为纯LaF_3晶体,晶粒尺寸在16～21 nm之间。在377 nm紫外光和X射线激发下,Tb~(3+)掺杂含LaF_3纳米晶的微晶玻璃比Tb~(3+)掺杂的锗酸盐玻璃表现出更强的绿光发射,且绿光发射强度随热处理温度升高和时间的延长而增强。微晶玻璃在X射线激发下的最大积分发光强度约为商用闪烁晶体Bi_4Ge_3O_(12)的40.3%。本研究表明,掺Tb~(3+)含LaF_3纳米晶锗酸盐微晶玻璃在X射线探测中具有潜在的应用前景。     

Er,Yb:YAG微晶玻璃发光特性的研究

高温熔制Er³⁺，Yb³⁺离子掺杂CaO-Y₂O₃-Al₂O₃-SiO₂系统玻璃，并进行微晶化处理，研究了微晶玻璃中Er³⁺离子的发光及上转换发光特性，分析了微晶玻璃上转换发光机理.结果表明：原始玻璃经热处理得到了Er,Yb:YAG微晶玻璃，微晶玻璃中Er³⁺离子在室温下⁴I_13/2→⁴I_15/2跃迁产生横盖1450—1650nm区间的超宽带荧光，荧光半高宽达180nm，这可能由于YAG微晶相中Er³⁺离子与玻璃相中残留Er³⁺离子的共同发光；Er³⁺与Yb³⁺离子局域基质声子能量的降低使微晶玻璃Er³⁺离子上转换发光强度与原始玻璃相比显著提高，绿光、红光上转换荧光强度比玻璃样品分别增强约7和3倍；微晶化后Er³⁺，Yb³⁺离子局域环境发生变化也导致微晶玻璃中Er³⁺离子绿光、红光上转换发光相对强度发生变化. 关键词： 铒 镱:钇铝石榴石 微晶玻璃 荧光光谱     

渗TiO_2高硅氧玻璃的光吸收性

本文研究了渗TiO_2高硅氧玻璃的结构与光吸收性。实验结果表明玻璃的光吸收决定于玻璃中的锐钛矿微晶,微晶增大、减小可使玻璃的光吸收限向长、短波方向移动。直径约80A的锐钛矿微晶就能显示出与大块晶体一样的光吸收限。     

The impact of the new Earth gravity model EIGEN-CG03C on the measurement of the Lense-Thirring effect with some existing Earth satellites

The impact of the latest combined CHAMP/GRACE/terrestrial measurements Earth gravity model EIGEN-CG03C on the measurement of the Lense-Thirring effect with some linear combinations of the nodes of some of the existing Earth's artificial satellites is presented. The 1-sigma upper bound of the systematic error in the node-node LAGEOS-LAGEOS II combination is 3.9% (4% with EIGEN-GRACE02S, ∼ 6% with EIGEN-CG01C and ∼ 9% with GGM02S), while it is 1% for the node-only LAGEOS-LAGEOS II-Ajisai-Jason-1 combination (2% with EIGEN-GRACE02S, 1.6% with EIGEN-CG01C and 2.7% with GGM02S).     

Super S_(25)与New S_(25)光电阴极的光谱响应特性的数值模拟

根据多碱光电阴极的光谱响应理论表达式 ,对荷兰DEP公司和日本Hamamatsu公司美国分公司开发的两种SuperS2 5阴极的光谱响应曲线进行了理论模拟 ,得到了这些阴极的有关特性参量 ,并通过对模拟结果的分析以及与美国夜视实验室研制的NewS2 5光电阴极特性的比较 ,揭示了两种SuperS2 5光电阴极内在机理和可能采用的工艺处理方法 ,对多碱光电阴极的理论研究和实际操作具有指导意义     

Comparison of performance between rescaled range analysis and rescaled variance analysis in detecting abrupt dynamic change

In the present paper, a comparison of the performance between moving cutting data-rescaled range analysis(MCR/S) and moving cutting data-rescaled variance analysis(MC-V/S) is made. The results clearly indicate that the operating efficiency of the MC-R/S algorithm is higher than that of the MC-V/S algorithm. In our numerical test, the computer time consumed by MC-V/S is approximately 25 times that by MC-R/S for an identical window size in artificial data. Except for the difference in operating efficiency, there are no significant differences in performance between MC-R/S and MC-V/S for the abrupt dynamic change detection. MC-R/S and MC-V/S both display some degree of anti-noise ability. However, it is important to consider the influences of strong noise on the detection results of MC-R/S and MC-V/S in practical application processes.     

SPINORS ON KAHLER–NORDEN MANIFOLDS

It is known that the complex spin group Spin(n, ?) is the universal covering group of complex orthogonal group SO(n, ?). In this work we construct a new kind of spinors on some classes of Kahler–Norden manifolds. The structure group of such a Kahler–Norden manifold is SO(n, ?) and has a lifting to Spin(n, ?). We prove that the Levi-Civita connection on M is an SO(n, ?)-connection. By using the spinor representation of the group Spin(n, ?), we define the spinor bundle S on M. Then we define covariant derivative operator ? on S and study some properties of ?. Lastly we define Dirac operator on S.     

点电荷、线电荷、面电荷模型的电荷体分布函数

利用δ函数,导出了点电荷、线电荷和面电荷模型在直角坐标、球坐标和柱坐标下的电荷体分布函数表达式,对处理一些具体的物理问题时十分有用。     

Linearity and symmetry

Linearity implies that, in general, there is no more than one preferential basis of a system S. Nevertheless, in two examples analyzed in this article we show that the validity of some symmetry arguments implies that S has more than one preferential basis.     

The competitiveness of U.S. manufacturers in the global market for fiber optics

U.S. manufacturers of fiber optic equipment continue to be major competitors in the world markets for these products. U.S. producers account for approximately half of the total worldwide production of optical fiber and cable. In active components for fiber optic transmission systems (transmitters, receivers, amplifiers, and related components), U.S. firms are beginning to recapture some of the market share previously lost to foreign competitors. This article provides a brief overview of the competitiveness of U.S. manufacturers in the global market for fiber optic equipment, with particular focus on European and Japanese competitors.     

Environment-mediated control of a quantum system

Recently, a new approach for the controllability of a two-dimensional quantum system S has been proposed, based on its interaction with an initially uncorrelated two-dimensional probe P whose initial state can be arbitrarily modified. Following this scheme and considering a particular model for the environment, we show that, in some specific cases, the environment-induced entanglement is rich enough to completely control the dynamics of S. Under suitable conditions on the interaction of S, P, and the environment, we prove that the state of S can be driven to an arbitrary target state by varying the initial state of P.     

Effect of S adsorption on magnetic Co(0001) surface: a DFT study

Extended density functional theory calculations with the spin interpolation formula of Vosko, Wilk, and Nusair (VWN) are employed to study the effect of atomic S adsorption on Co(0001) surface. Besides the site preference for atom S in fcc-hollow site and adsorption geometry structures are in good agreement with experiments and previous calculations, some differences are also reported for the geometry of S in hcp-hollow site. Moreover, vibrational frequency, magnetic moments and electronic structure analysis are presented in more detail.     

Production of Some Inorganic Forms of 35S at the Boris Kidrie Institute

Some inorganic forms of ³⁵S are used as starting material for some chemical syntheses of labelled organic compounds. The choice depends on the desired characteristics of the labelled compound. Preparation of elementary sulphur ³⁵S, sodium sulphide-³⁵S, ferrous sulphide-³⁵S, barium sulphate-³⁵S, barium sulphide-³⁵S, is described. The characteristics of the products, along with determination methods, are given. The products are obtained with high specific activities: elementary sulphur-³⁵S, 1 – 5 Ci/g S; sodium sulphide-³⁵S 1 – 5 Ci/g S; ferrous sulphide-³⁵S, 1 – 5 Ci/g S; barium sulphate-³⁵S, 5 – 15 Ci/g S; barium sulphide-³⁵S, 1 – 5 Ci/g S.