NaGdF4:Eu3+的结构和VUV荧光性质

利用水热方法合成了纯度较高的六方结构的ＮaGdF4,在氧气存在条件下950℃加热处理可以使其转变为CaF2型立方结构,在真空紫外光激发下,六方结构的NaGdF4:Eu^3 中的Gd^3 离子吸收一个光子,并将能量分两步传递给Eu^3 离子,发生双光子发射,立方结构的NaGdF4:Eu^3 中存在有一定量的氧离子取代缺陷,使Gd^3 离子4f-5d跃迁移到177nm附近,这与惰性气体放电产生的真空紫外波长一致。     

Luminescence characteristics of undoped and Eu‐doped GdCa4O(BO3)3 single crystals and nanopowders

Single crystals of GdCa₄O(BO₃)₃ (GdCOB) pure and doped with Eu concentration of 1 and 4 at% were grown by the Czochralski and micropulling‐down methods. The distribution of Eu ions in GdCOB crystals was uniform. The substitutions of Eu³⁺ in Gd, Ca(1) and Ca(2) cation sites and eventually formation Eu²⁺ have been investigated. The spectroscopic properties of crystals are compared with the properties of nanopowders obtained by sol‐gel method. Radioluminescence spectra of undoped GdCOB crystal show the characteristic emission of Gd³⁺ at about 312 nm, whereas this emission dramatically decreases in Eu‐doped crystals upon X‐ray excitation, as well as in Eu‐doped nanopowders excited in vacuum ultraviolet (VUV) region. The VUV excitation in the range 125‐333 nm for Eu‐doped samples leads to strong emission in red coming from the ⁵D₀ multiplet of Eu³⁺, only. In the photoluminescence decay kinetics of 312 nm emissions substantial shortening and departure for single exponential decay in Eu‐doped samples is clearly observed. Higher Eu doping results in further acceleration of the decay. In undoped GdCOB crystal, the lifetime of the Gd^{3+ 6}P_7/2 multiplet is 2.79 ms. The Eu^{3+ 5}D₀ decay kinetics monitored at 613 nm are rather constant. Numerical fitting of fully exponential curves, reveals lifetimes 2.7 ms for nanopowder and 2.5 ms for single crystal. The results suggest that this material may be used as a red phosphor in plasma display panels in nanopowder form because of strong excitation band of Eu³⁺ luminescence in the 160‐200 nm regions. Contrary to nanopowder sample, such an excitation band, attributed to the Gd³⁺–O^2– charge transfer was not observed in crystal obtained by the micropulling‐down method. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Ln7O6（BO3）（PO4）2：Eu（Ln=Al,Gd,Y）的UVU—UV激发和辐射发光

本文报道了Ln7O6(BO3)(PO4)2:Eu(Ln=La,Gd,Y)在UVU－UV区的激发光谱及Eu^3 在可见区的发射光谱,其激发光谱包括基质在真空紫外区的激发带和激活剂离子在紫外区的Eu^3 -O^2-电荷迁移带,随着La^3 ,Gd^3 ,Y^3 离子半径逐渐减小,Eu^3 -O^2-电荷迁移带的重心位置逐渐向高能量方向移动,Gd7O6(BO3)(PO4)2:Eu和Y7O6（BO3）（PO4）2：Eu在真空紫外区的吸收与Eu^3 -O^2-电荷迁移带位于紫外区的吸收的比值要高于在La7O6(BO3)(PO4)2:Eu中的这个比值,激发能可被基质吸收,传递给激活剂离子,得到Eu^3 的红光发射,在Gd7O6(BO3)(PO4)2:Eu中,^5D0→^7F1的发射强度较强,在Y7O6（BO3）（PO4）2：Eu中,^5D0→^7F2和^5D0→^7F3的跃迁较强。     

Evaluation of a low-resolution near-IR monochromator for atomic emission detection in capillary gas chromatography

A single 0.2 m focal length near-IR monochromator providing a 0.8–3.2 nm effective bandpass was evaluated as spectrometer for F-, Cl-, Br-, I-, S-, and P-selective atomic emission detection in capillary gas chromatography. With optimized plasma conditions and careful wavelength selection, interferences from eluting hydrocarbons were almost eliminated for all the elements studied (element-to-carbon selectivities between 1000:1 and 10000:1). For Cl and S, other heteroatoms were found not to cause cross-interferences. F-, Br-, I-, and P-selective detection, however, was complicated by this second type of non-specificity. For these atoms, elemental confirmation was carried out by analyzing the samples also for heteroatoms potentially causing interferences.     

HL-1装置掠入射真空紫外杂质谱线观测

本文叙述用掠入射谱仪在HL-1装置上所做的真空紫外光谱测量。根据杂质谱线的相对强度变化,说明可动石墨孔栏和蒸钛技术对控制等离子体杂质有一定效果。通过分析谱线、软X射线和m=2模式信号扰动之间的关系,指出杂质对等离子体不稳定性的影响。     

真空紫外双等离子体光源的研究

本文描述我们研制的真空紫外双等离子体光源的设计、结构及工作原理,讨论真空紫外性能测试,给出光源的真空紫外辐射特性测试结果。     

La2CaB10O19：Eu^3＋的VUV—VIS范围光谱的研究

研究了La2CaB10O19:Eu^3 红色发光材料的高分辨发射光谱和UV－VUV激发光谱，根据发射光谱和荧光寿命，认为进入晶格的Eu^3 占据了两种格位，一种Eu^3 占据了与O^2-离子十配位的La^3 的格位，另一种Eu^3 则占据了与O^2-离子八配位的Ca^2 的格位，又从激发光谱的分析中，得到Eu^3 的电荷迁移带（CTB）是峰值位于244mm的带，而位于130－170nm之间的成份复杂的宽带包括硼酸盐基质的吸收带和Eu^3 的f-d跃迁的结论。     

Removal and mineralization of toluene under VUV/UV lamp irradiation in humid air: Effect of light wavelength,O2 and H2O

VUV/UV photodegradation is a promising method that utilizes energetic photons and reactive oxygen species (ROS) generated via the photo-dissociation of H₂O and O₂ to degrade VOCs. In the paper, we investigated the efficiency of removal and mineralization in humid air and the effects of key factors. Toluene of 4–20 ppm can be almost completely removed in 60 s and mineralization efficiency is above 55% at 25 min. 185 nm ultraviolet light plays a key role in the rapid removal and mineralization of toluene. Appropriate amount of O₂ and H₂O promote the removal of toluene due to the generation of ROS. Based on the intermediates and degradation pathway analysis, it is found that in the presence of O₂, degradation pathways of toluene are more abundant and fewer linear-chain aldehydes are produced, thus resulting in higher mineralization efficiency. This work highlights the importance of practical application of VUV/UV photodegradation in humid air.     

HL—1装置低杂波驱动,靶丸注入,ECRH实验的杂质行为研究

本文叙述了在ＨＬ－１装置上利用真空紫外光谱测量系统，通过观测低杂波驱动，靶丸注入，ＥＣＲＨ和高密度氦放电的杂质辐射，研究杂质的行为，产生和输运等特性。     

真空紫外光谱时空分辨测量

利用光谱仪前置旋转多面镜技术，在单次托卡马克脉冲放电过程中实现了真空紫外光谱的时空分辨测量，避免了传统测量方法因连续重复放电带来的不准确性。．