LUMINESCENCE OF BI(3+) AND THE ENERGY-TRANSFER FROM BI(3+) TO R(3+) (R=EU,DY,SM,TB) IN ALKALINE-EARTH BORATES

At room temperature, the Bi3+ ion shows broad band characters of its luminescence in Ca2B2O5, M3B2O6 ( M=Ca,Sr ) and SrB4O7. The maxima of the Bi3+ S-1(0)-->P-3(1) absorption bands are located in the range of 240-300nm, but the energy variation of the corresponding P-3(1)-->S-1(0) emissions is very large. The maxima of these emission bands change from 350nm in Ca3B2O6;Bi3+ to 586nm in SrB4O7:Bi3+. The Stokes shift of the Bi3+ luminescence increases from 6118 cm-1, in Ca2B2O5:Bi3+, to 24439 cm-1, in SrB4O7:Bi3+. The emission intensity of the Bi3+ luminescence increases with the decreasing Stokes shift. It has been found that in Ca2B2O5, the Bi3+ ion could transfer its excitation energy to the R3+ ions ( R=Eu, Dy, Sm, Tb ) , but in, Ca3B2O6 and Sr3B2O6, only Bi3+-->Eu3+ was observed. No energy transfer from Bi3+ to R3+ was detected in SrB4O7.

La_4(P_2O_7)_3:Ce,Gd,Tb磷光体的合成与光谱性质

本文首次采用溶液沉淀法合成了一系列La_4(P_2O_7)_3;Ce,Gd,Tb磷光体.经X射线分析表明,它们属于纯的La_4(P_2O_7)_3相。测定了这些化合物的激发和发射光谱、相对亮度及Ce~(3+)的发光寿命,观察到在此基质中Ce~(3+)与Gd~(3+)的光谱重叠,它们之间存在着一定的相互作用,使(La_(0.64)Ce_(0.3)Gd_(0.06)_4(P_2O_7)_3的亮度比(La_(0.7)Ce_(0.3)_4(P_2O_7)3和(La_(0.94)Gd_(0.06)_4(P_2O_7)_3有少许增加.此外,Ce~(3+)能有效地敏化Tb~(3+)~9,从而大大增强Tb~(3+)的发射.然而,Gd~(3+)与Tb~(3+)共存时存在着竞争吸收和独自发射,使(La_(0.80)Gd_(0.06)Tb_(0.14)_4(P_2O_7)_3的亮度与单掺的(La_(0.86)Tb_(0.14)_4(P_2O_7)3相比有少许降低.相应地在Ce,Gd和Tb共掺时,由于Gd~(3+)的影响,使Tb~(3+)的发射减弱,从而总的发光相对亮度有所降低。

YVO_4∶RE~(3+)(RE∶Pr、Sm、Tb、Es、Dy)晶体的研究

本文探讨了助熔剂法生长 YVO_4:RE~(3+)(RE:Pr,Sm,Tb,Er,Dy)晶体的工艺。讨论了助熔剂 V_2O_5,Pb_2P_2O_7和温度对晶体生长习性和缺陷的影响。测定了晶体的结构参数和光谱。Y_(0.9)Sm_(0.1)VO_4和 Y_(0.95)Dy_(0.05)VO_4晶体具有很好的光谱特性。

LaP_3O_9:Ce,Tb磷光体的合成与光谱特性

Ce~(3+)离子有宽而强的4f-5d吸收带,能有效地吸收能量,并形成强的宽带发射。Ce~(3+)的5d-4f跃迁是允许的电偶极子跃迁,其5d态的寿命非常短。为此Ce~(3+)可将能量有效地传递给其它离子,而成为良好的敏化剂。通常Ce~(3+)对Tb~(3+)的敏化十分有效,已有许多Ce~(3+)敏化Tb~(3+)的绿色发光材料。稀土磷酸盐是发光和激光材料的良好基质,LaPO_4:Ce,Tb已用作灯用三基色荧光粉,对不同类型稀土磷酸盐中Ce~(3+)、Tb~(3+)的发光已有不少报道,为探索新的高效

硼酸盐玻璃中Gd~(3+)、Dy~(3+)、Bi~(3+)对Tb~(3+)发光性质的影响

本文研究了单掺和双掺(Tb~(3+)、Tb~(3+)+Gd~(3+)、Tb~(3+)+Dy~(3+)、Tb~(3+)+Bi~(3+)约四十余种不同成份的硼酸盐玻璃。探讨了玻璃成份对Tb~(3+)发光性质的影响和Gd~(3+)、Dy~(3+)、Bj~(3+)对Tb~(3+)的胜化作用。在B_2O_2-BaO-M_mO_n(M_mO_n=Li_2O、Na_2O、K_2O、MgO、CaO、SrO、Al_2O_3、La_2O_3和Bi_2O_3)玻璃体系中,当M_mO_n分别为MgO和Al_2O_3时,Tb~(3+)的发光强度最强;M_mO-n为Bi_2O_3时,Tb~(3+)的发光强度最弱。Tb~(3+)的特征发射峰分别随着碱金属、碱土金属和三价金属的离子半径增加而红移。Gd~(3+)、Dy~(3+)、Bi~(3+)对Tb~(3+)均有敏化作用。特别是Gd~(3+),使Tb~(3+)的发光强度增加1～3.8倍,其最佳敏化浓度,因基质玻璃成份而异。

用化学氧化法分析混合稀土中的Tb

根据 Tb在 K IQ_4—KOH—K_2S_2O_8体系中的氧化反应,建立了混和稀土中 Tb 的分光光度分析方法.Tb被氧化为 Tb~(4+),其颜色由无色转变为红棕色,最大吸收峰在420nm.Ce~(3+)加入 KIO_4—KOH 溶液后,立即被完全氧化为 Ce~(4+),Ce~(4+)在420nm 也有吸收,其干扰可以在本底中排除,其它三价稀土离子在此体系中不能发生氧化反应,故无干扰.在 Tb 的分析浓度范围为5×10~(-5)～5×10~(-4)M 时,符合 Beer 定律,Tb 在混合稀土中含量分析的最低限为1%。此方法可用于萃取稀土过程中 Tb 的分析和监控,方法简便快速。

LnAlO_3中Ce~(3+),Tb~(3+),Dy~(3+)的发光及Ce-Tb,Ce-Dy的敏化发光(Ln=La,Gd,Y)

本文采用BaF_2作为助熔剂和抑制剂经固相反应合成了一系列以LnAlO_3(Ln=La,Gd,Y)为基质的磷光体,系统地研究了LnAlO_3中Ce~(3+),Tb~(3+),Dy~(3+)的发光及Ce-Tb,Ce-Dy的敏化发光,发现随Ln的不同,LnAlO_3作为基质对激活剂的发光性质的影响也不同,本文得到一些规律性结果,并作了讨论。

LaPO_4:Ce,Gd,Tb磷光体的合成及其发光

稀土三基色荧光粉具有高的发光效率、高的显色性和显著的节能效果,已引起国内外的广泛重视、并开展了大量的研究。其中绿色荧光粉的发光峰值波长与视感度曲线的峰值波长几乎一致,对三基色荧光灯的发光效率影响最大,因此研究高效的绿色荧光粉

用三组份同时分离法氨化萃取分离Gd-Tb-Dy

用普通分馏萃取工艺分离物质一次只能分离两个组份,若连续分离多种物质,则需很长工艺流程.文献[1]报导了用N_(26?)萃取分离La-Pr-Nd的三出口串级实验结果.本文报导用氨化HEH(EHP)同时萃取分离Gd-Tb-Dy的串级试验结果.

助熔剂法合成RPO_4(R=La、Ce、Tb)晶体的研究

本文研究了以(NH_4)_2HPO_4-Li_2CO_3-MoO_3(PbF_2)为助熔剂合成 RPO_4(R=La~(3+),Ce~(3+),Tb~(3+))晶体的工艺,测试和分析了晶胞参数和晶体结构。对 CePO_4和 TbPO_4晶体的激发光谱和荧光光谱进行了讨论和分析。

RE_(0.06)La_(0.94)Nb_2O_6Cl的制备与光谱性质(RE=Pr、Eu、Tb、Dy)

本文采用真空下气体输运技术制备RE_(0.06)La_(0.94)Nb_2O_6Cl(RE=Pr、Eu、Tb、Dy)小单晶和多晶粉末样品。测定其晶体结构与LaNb_2O_6Cl的晶体结构相同,为正交晶系;Eu_(0.06)La_(0.94)Nb_2O_6Cl小单晶的晶胞参数为:a=9.751,b=7.321,c=8.364。观察RE_(0.06)La_(0.94)Nb_2O_6Cl(RE=Pr、Eu、Tb、Dy)的特征激发光谱和发射光谱及其能量传递现象。

NaGd_(1-x)(Eu,Tb)_x TiO_4化合物的光谱

研究了NaGd_(1-x)(Eu·Tb)_xTiO_4(X=0.01～0.5)化合物的合成,结构和光谱特性,观察了Li~+,Na~+,K~+和Mn~(4+),Ge~(4+),Si~(4+)对E_u~(3+)离子~5D-~7F跃迁荧光发射的影响,讨论了Gd~(3+)→Eu~(3+),Eu~(3+)-Tb~(3+)离子间的能量转移

Project Sanitarium: gaming TB: a serious game for a serious problem

Collaborative projects between Industry and Academia provide excellent opportunities for learning. Throughout the academic year 2014-2015 undergraduates from the School of Arts, Media and Computer Games at Abertay University worked with academics from the Infection Group at the University of St Andrews and industry partners Microsoft and DeltaDNA. The result was a serious game prototype that utilized game design techniques and technology to demystify and educate players about the diagnosis and treatment of one of the world's oldest and deadliest diseases, Tuberculosis (TB). Project Sanitarium is a game incorporating a mathematical model that is based on data from real-world drug trials. This paper discusses the project design and development, demonstrating how the project builds on the successful collaborative pedagogical model developed by academic staff at Abertay University. The aim of the model is to provide undergraduates with workplace simulation, wider industry collaboration and access to academic expertise to solve challenging and complex problems.

Incidence and predictors of mortality and the effect of tuberculosis immune reconstitution inflammatory syndrome in a cohort of TB/HIV patients commencing antiretroviral therapy.

info:eu-repo/semantics/published

Contribution of a heparin-binding haemagglutinin interferon-gamma release assay to the detection of Mycobacterium tuberculosis infection in HIV-infected patients: comparison with the tuberculin skin test and the QuantiFERON-TB Gold In-tube.

The screening and treatment of latent tuberculosis (TB) infection reduces the risk of progression to active disease and is currently recommended for HIV-infected patients. The aim of this study is to evaluate, in a low TB incidence setting, the potential contribution of an interferon-gamma release assay in response to the mycobacterial latency antigen Heparin-Binding Haemagglutinin (HBHA-IGRA), to the detection of Mycobacterium tuberculosis infection in HIV-infected patients.