铒钇铝石榴石激光晶体的研究

研究了引上法生长铒钇铝石榴石的生长工艺。对于不同的铒离子渡度(15—100at.％),获得了直径23—25mm、有效长度100mm以上的优良单晶。测试了与晶体激光行为有关的性能:吸收光谱、荧光光谱和折射率。从铒离子浓度为50at.％的晶体中获得了2.938μm激光。最后讨论了提高激光效率的途径。     

掺钕钆镓石榴石晶体的激光性能

采用提拉法生长了Nd：Gd3Ga3O12（Nd：GGG）晶体。切割后的样品经过端面抛光,测试了荧光光谱、吸收光谱和激光性能。荧光光谱表明：晶体的最强的荧光发射峰位于1062nm,是Nd^3＋的4^F3/2-4^I11/2谱项导致的荧光发射。由吸收光谱发现：Nd：GGG晶体的最强吸收峰位于808nm,表明该晶体适合于激光二极管泵浦．并且吸收峰强度随掺杂离子浓度的增加而增加。激光性能测试结果表明：激光二极管泵浦时光-光转换效率为33.＋8％,斜效率为57.8％。     

石榴石系列闪烁晶体的研究进展

主要对石榴石系列闪烁晶体近10多年的研究和发展情况进行了梳理。介绍了Pr、Ce掺杂的(Lu,Y)AG晶体中不同发光中心的发光机理、能量的传递、载流子再束缚过程等;阐述了反位缺陷(antisite defect,AD)对发光中心发光性能的影响及其作用机制;用带隙工程理论分析了Gd、Ga掺入可以消除AD缺陷副作用的机理。展示了新型石榴石晶体Gd3(Ga5–xAlx)O12:Ce(GGAG:Ce)晶体的光产额和能量分辨率,预计这类多组分掺杂将把石榴石晶体的发展引入一个新的阶段。     

稀土铈离子掺杂镥铝石榴石光学透明闪烁陶瓷

首先简单介绍了国际上目前在闪烁透明陶瓷研究领域所涉及的材料体系、发展水平及存在的主要问题,然后重点介绍中国科学院上海硅酸盐研究所近年来在稀土铈离子掺杂镥铝石榴石(LuAG:Cze)透明闪烁陶瓷的制备、微观结构和光学性能等方面的研究结果。采用高温固相反应和共沉淀方法通过真空烧结工艺可制备透过率达77%的LuAG:Ce透明陶瓷。材料显微结构均匀,平均晶粒尺寸为10μm。在γ射线激发下、在国际上首次成功实现了闪烁输出,光产额为4818光子/MeV,为同样条件下测定的LuAG:Ce单晶的45%,锗酸铋(bismuth germanate,BGO)单晶的60%。最后,指出具有各向同性的立方材料体系、高质量粉体原料的制备以及降低光学散射损耗的有效方法是研制高质量光学透明陶瓷材料的关键因素。     

YAG掺铷——钇铝石榴石激光晶体胶粘剂

YAG掺铷——钇铝石榴石激光晶体胶粘剂以丁腈改性环氧树脂,酚醛变性胺为固化剂,用于掺铷——钇铝石榴石激光晶体与钢套粘接,安装在陕西省人民医院YAG激光医用治疗机,临床应用3年,效果很好。后中国电子科技集团第二十七研究所从1990年开始用YAG激光胶粘剂粘接各类激光产品至今,经高低温试验、振动试验、冲击试验等各项性能测试及15年来工程应用证明,在各类激光产品中从未出现开裂、脱胶现象,性能稳定可靠,其粘接强度、耐冲击、耐振动、耐高低温变化、耐水、耐化学介质、耐光、耐老化性能均好,能满足生产要求,用途广泛,符合激光及各种工程应用。文中详述了酚醛变性胺固化剂的选择及该胶粘剂的性能。     

掺铥钇镓石榴石激光晶体的生长及其光学性能EI北大核心CSCD

采用光浮区法生长了掺铥钇镓石榴石（Tm：Y3Ga5O12,Tm：YGG）激光晶体,探索了Tm：YGG晶体的光学性能,测试了其室温吸收谱并计算了吸收截面和发射截面。使用中心波长为795 nm的激光二极管作为泵浦源,实现了Tm：YGG晶体的连续激光输出,得到了波长为2 012.8 nm的激光,阈值为0.515 W,斜效率为9.9%,光光转换效率为9.3%。结果表明Tm：YGG晶体在2μm波段可能有好的应用前景。     

碳泡沫的结构及其性能

综述了碳泡沫的发展概况，着重描述了碳泡沫的制备方法、结构特点及力学、热学性能，并介绍了碳泡沫在绝热材料、导电材料等方面的应用。     

LuAG纳米粉体的制备研究

综述了LuAG纳米粉体常用的制备方法:固相反应法、共沉淀法、溶胶-凝胶燃烧法、混合溶剂热法及溶剂热法等,简要地分析了各种方法的优缺点,并展望了溶剂热法是目前LuAG纳米粉体制备中最具发展前景的一种合成方法。     

Spectral and Laser Properties of Yb:LuAG Transparent Ceramics Fabricated by Tape Casting Method

Yb³⁺‐doped LuAG laser ceramics with different Yb³⁺‐doping concentrations were successfully fabricated by nonaqueous tape casting method and vacuum sintering technology. XRD patterns and SEM morphologies of the ceramics were presented. The optical in‐line transmittance of the Yb‐doped LuAG ceramics was about 83% at 1030 nm. The fluorescence lifetime of annealed and unannealed ceramic samples was compared. From the spectroscopic properties, it can be seen that the ceramics had a large emission cross section of 2.9 × 10^?20 cm² with a FWHM of about 7.2 nm at 1030 nm. Under 100% population inversion, the maximum gain coefficient was estimated to be 12.4 cm^?1 at 1030 nm. With a fiber‐coupled diode laser as pump source, CW laser at 1030 nm was demonstrated and the maximum output power of 338.9 mW was achieved with a slop efficiency of 19%. A tuning range from 1028 to 1036 nm was obtained.     

液晶热性能的研究

讨论了液晶聚合物及相应的液晶单体的热性能,指出液晶聚合物的液晶温度区间总量宽于液晶单体。通常在侧链液晶聚合物中第二种单体的引 导致液晶温度区间变宽。     

Influence of cerium doping concentration on the optical properties of Ce,Mg:LuAG scintillation ceramics

Ce,Mg:LuAG scintillation ceramics with Ce dopant content ranging from 0.025?at.% to 0.3?at.% and constant 0.2?at.% Mg codoping were fabricated by solid-state reaction. The effects of Ce concentration and annealing conditions on the microstructure, optical quality and scintillation properties are studied in great details. Lattice parameters as well as the absorption, photoluminescence, radioluminescence and thermoluminescence characteristics are investigated as a function of Ce content. Both the photoluminescence and scintillation decays are measured as well in order to study re-absorption and concentration quenching processes. In addition, an enhanced positive effect of air annealing on radioluminescence intensity and light yield is put in evidence. Moreover, the role of the charge transfer absorption of Ce⁴⁺ is investigated. Thermoluminescence measurements are performed to investigate the influence of both air annealing and Ce concentration on defects acting as traps. Finally, the correlations among steady state scintillation efficiency, light yield, thermoluminescence and Ce³⁺ concentration are found and discussed.     

Effective calcination pretreatment of Lu2O3 powders for LuAG transparent ceramics

Lutetium aluminium garnet (LuAG) ceramics as host materials has been widely used in lighting, laser, displaying and scintillators after doping different rare earth ions. Right selection of raw powder and controlling its characteristics during the preparation can greatly improve the optical quality of transparent ceramics. In this paper, the influence of different pretreatment temperatures of commercial Lu₂O₃ powders in oxygen atmosphere on solid state sintering of LuAG ceramics was systematically investigated. The pretreatment gradually decreased the specific surface area of Lu₂O₃ powders and greatly removed the absorbed impurities, which seriously deteriorated the optical quality before. The mean particle size increased from 4.53 to 5.66 μm, and the in-line transmittance of samples (Thickness = 2 mm) at 1064 nm was 68.4% for the pretreated Lu₂O₃ powder at 1000 °C without any sintering additives. Further increase of pretreatment temperature would lead to the coarsening of Lu₂O₃ powders and the decrease of sintering activity, which finally resulted in a large number of micro pores in LuAG ceramics. These results revealed that the pretreatment of Lu₂O₃ powders has prodigious impact on the optical quality of LuAG transparent ceramics, and the adsorbed materials should be removed as much as possible for their applications in lasers or lighting.     

Pechini溶胶-凝胶法制备LuAG:Tb薄膜的显微结构及发光性能

采用Pechini溶胶-凝胶法结合旋涂工艺制备了Tb³⁺掺杂Lu₃Al₅O₁₂（简称LuAG:Tb）发光薄膜。前驱体薄膜在850℃左右锻烧得到单一石榴石相的LuAG:Tb薄膜。LuAG薄膜的发射光谱（268nm紫外光激发）对应于Tb³⁺的⁵D₄→⁷E_J（J=6～0）和⁵D₃→⁷F_J特征跃迁,光谱强度随Tb³⁺掺杂浓度的升高先增强后减弱,在x(Tb³⁺)=2.0%时光谱强度最强,其发光衰减时间为5.14ms。扫描电镜（SEM）和原子力显微镜（AFM）观察显示LuAG薄膜的颗粒度大小和表面粗糙度随煅烧温度的升高而增大。     

杯芳烃的催化性质及其在有机反应中的应用

本文描述了杯芳烃的结构以及它由于此结构而具有的特殊性质。并对杯芳烃的合成作了总结。杯芳烃可以作为相转移催化剂,也可以模拟生物酶并且作为催化剂时有时有立体选择性。本文也对杯芳烃作为各种有机反应的催化剂作了综述。作为相转移催化剂时可以应用在醚合成反应、酯化反应、氧化反应、加成反应、脱水反应、聚合反应和亲核取代反应中,作为模拟酶时可以应用在区域选择催化反应的苯乙烯环氧化反应中。     

The influences of stoichiometry on the sintering behavior,optical and scintillation properties of Pr:LuAG ceramics

Sintering aids may enter the host lattice, create defects, and seriously deteriorate the scintillation properties of ceramic scintillators. In this study, the 0.3at%Pr:LuAG ceramics with different excess of Lu were fabricated by the solid-state reactive sintering without aids. The influences of stoichiometry on the sintering behaviors, optical and scintillation properties of the ceramics are systematically studied. The results show that the stoichiometric ceramics experience an abnormal grain growth during sintering. The Lu excess can restrain the abnormal grain growth of the ceramics because of the impurity drag effect. The excess Al₂O₃ as optical scattering centers, can also pin in the grain boundary to limit the fast migration of the grain boundaries. The light yield value of the as-sintered ceramics decreases with the increase of Lu content. After air-annealing, the ceramics with appropriate excess of Lu can achieve better optical quality and higher light yield compared to the stoichiometric Pr:LuAG ceramics.     

近化学计量比Cu:Fe:LiNbO3晶体的生长及蓝光优化光折变性能

以K2O为助溶剂在LiNbO3中掺入0.15%(质量分数,下同)CuO,0.03%和0.05%Fe～03,用顶部籽晶溶液生长法生长近化学计量比Cu:Fe:LiNbO3晶体.以Ar+激光器的488nm激光为光源测试Cu:Fe:LiNbO3晶体的光激载流子类型,采用二波耦合光路测试了晶体的光折变存储性能,并与633nm红光...     

三氯异氰脲酸的性质及应用

详细分析了三氯异氰脲酸的性质与性能。并详细评价了国内外三氯异氰脲酸的用途及应用。