硅酸盐体系长余辉发光材料的合成研究

硅酸盐是一种性能稳定的基质材料.本文综述了硅酸盐体系长余辉的发展历史,制备方法和发光机理等方面的最新进展.指出了目前该类材料研究中存在的问题,并提出从基质材料、制备技术和稀土离子发光机制入手是长余辉发光材料今后研究与开发的发展方向.     

稀土掺杂红色长余辉发光材料的研究进展

介绍了稀土掺杂红色长余辉发光材料的研究进展,总结了硫化物、硫氧化物、钛酸盐等基质体系的红色长余辉发光机制。及传统的高温固相法以及溶胶-凝胶法、燃烧法等稀土红色长余辉材料的制备技术,提出了对红色长余辉材料今后发展的看法。     

稀土掺杂红色长余辉发光材料的研究进展

介绍了稀土掺杂红色长余辉发光材料的研究进展,总结了硫化物、硫氧化物、钛酸盐等基质体系的红色长余辉发光机制.介绍了传统的高温固相法以及溶胶-凝胶法、燃烧法等稀土红色长余辉材料的制备技术.提出了对红色长余辉材料今后发展的看法.     

稀土掺杂红色长余辉发光材料的研究进展

介绍了稀土掺杂红色长余辉发光材料的研究进展,总结了硫化物、硫氧化物、钛酸盐等基质体系的红色长余辉发光机制.叙述了传统的高温固相法以及溶胶-凝胶法、燃烧法等稀土红色长余辉材料的制备技术.提出了对红色长余辉材料今后发展的看法.     

高温固相法制备硅酸盐长余辉发光材料

使用碳还原法和气体还原法制备硅酸盐长余辉材料,探讨了不同铕、镝含量,不同硼含量,烧成方式和二氧化硅粒径对样品余辉性能的影响.结果表明:硅酸盐长余辉材料中硼含量的提高可有效降低烧成温度,但发光性能也随之下降.不同铕、镝含量的样品对应不同的适宜硼含量.选择适当纯度和颗粒组成的SiO2有利于改善硅酸盐长余辉材料的结构和发光性能.气体还原法所得硅酸盐长余辉材料的发光性能优于碳粉还原法.组成为Sr1.97MgSi2O7:(Eu0.005,Dy0.025,B0.15)的样品有较好的发光性能,余辉时间超过10 h.     

长余辉发光材料研究进展

阐述长余辉发光材料制备方法，主要激活剂组分在发光材料中的作用，助熔剂组分B2O3对发光材料晶相的稳定和发光性质的作用。     

长余辉发光材料进展

综述了近几年来长余辉发光材料研究的最新进展,对发光材料的研究现状,合成方法和发光机理进行了一些概括性的介绍,并提出了今后研究的方向。     

钛酸盐体系长余辉发光材料研究进展

钛酸盐基质长余辉发光材料具有稳定的物化性能,是一类新型的储能和环保型材料。综述了近年来钛酸盐体系长余辉发光材料的最新研究进展,总结了掺杂离子、基质种类、电荷补偿以及制备方法等对钛酸盐长余辉发光材料发光特性的影响,并提出了今后可能的研究和应用发展方向。     

稀土蓝色长余辉发光材料的研究进展

综述了稀土元素掺杂蓝色长余辉发光材料的研究进展,总结了硫化物、铝酸盐、硅酸盐等基质体系的蓝色长余辉发光材料,对有关制备蓝色长余辉发光材料的方法进行了描述,比较了各种制备方法的优缺点。     

稀土蓝色长余辉发光材料的研究进展

综述了稀土元素掺杂蓝色长余辉发光材料的研究进展，总结了硫化物、铝酸盐、硅酸盐等基质体系的蓝色长余辉发光材料，对有关制备蓝色长余辉发光材料的方法进行了描述，比较了各种制备方法的优缺点，最后对发光机理进行了阐述。     

Optical glass-ceramics based on fluorine-containing silicate glasses doped with rare-earth ions

Oxyfluoride silicate glasses in the SiO₂-Al₂O₃(AlF₃)-CdF₂-PbF₂-ZnF₂-Eu₂O₃ system are studied. Glass-ceramic materials with special properties promising for use of these glass-ceramics as active optical media are synthesized from the oxyfluoride glasses under investigation. The physicochemical and spectral-luminescence properties of the glass-ceramic materials synthesized are investigated. It is shown that the composition of glasses and, consequently, their thermal and physical properties depend on the synthesis conditions. Heat treatment of glasses doped with Eu³⁺ ions at temperatures somewhat higher than the glass transition point T _g leads to the formation of β-PbF₂ nanocrystals such that the major part of the dopant enters into the nanocrystal composition.     

杂原子掺杂微孔碳材料的研究进展

概述了微孔碳材料和杂原子掺杂微孔碳材料的制备方法并对其发展前景进行了展望。微孔碳材料具有稳定性好、高比表面积、表面容易改性等一系列优点,将杂原子掺杂在微孔碳材料中,可以使其性能得到进一步的优化,扩大应用的范围。大量实验研究表明,开发杂原子掺杂微孔碳材料具有更加广阔的前景。     

Effect of dopant precursors on the optical properties of rare-earths doped oxyfluoride glass-ceramics

The crystallization of fluoride nanocrystals (NCs) in chemically and mechanically stable aluminosilicate glasses has shown interesting optical properties even for small crystal fractions (10-15 wt%). When rare-earth (RE) ions are used as dopants, crystal-like features can be reproduced and an increase in the emission and/or energy transfer processes, with respect to the starting glasses, is observed. A crucial point for these materials is the study of the local surrounding of RE ions and their incorporation in the NCs. In fact, the effective concentration in the NCs can be much higher than the nominal concentration, up to one order of magnitude or even higher. The knowledge of RE ions incorporation in the NCs permits choosing proper doping levels to optimize both linear and nonlinear optical properties. In this work, transparent oxyfluoride glass-ceramics with LaF₃ NCs, doped with Nd³⁺ and Er³⁺ using oxide and fluoride precursors, were prepared using the melt-quenching method and controlled crystallization. The local surrounding of the RE ions was studied using X-ray absorption spectroscopy, electron paramagnetic resonance and photoluminiscence. The results show that most RE ions are already in a fluorine-rich amorphous environment even in the initial glass. The crystallization process provokes the RE ion redistribution and incorporation in the fluoride NCs. The different RE precursors, used as oxides or fluorides, have an influence on the incorporation of the RE in the NCs and, as a consequence, on the final optical properties.     

Crystallization behaviour of neodymium doped yttrium silicate nanophosphors

Sol-gel technique was used to prepare yttrium silicate powders doped with 0.01Nd³⁺. The crystallite sizes were determined to be 23 ± 0.5 nm from the XRD patterns of the powders annealed at 960 °C. The Y_4.67(SiO₄)₃O, Y₂Si₂O₇ and Y₂SiO₅ crystalline phases were observed upon heat treatment at 960 °C which is much lower than 1500-1650 °C are reported before.     

层状硅酸盐 /聚合物纳米复合材料的研究现状与前景

基于1996年以后的40余篇文献和作者的研究成果，综述了层状硅酸盐／聚合物纳米复合材料在制备技术、新品种、新性能、相关理论及应用等方面的最新研究进展，并总结出了以下观点：（1）粘土的有机化是制备纳米复合材料的第一关键要素，单体、预聚体、聚合物熔体与有机土的相容性是制备纳米复合材料的必要条件，外界剪切力可提供帮助；（2）剥离型结构最能体现层状硅酸盐／聚合物纳米复合材料的性能优势，是层状硅酸盐／聚合物纳米复合材料的制备方向；（3）聚合物熔体插层法为简单，是重要的发展方向，要形成剥离型结构，需要同时考虑热力学和动力学因素，基体或相容剂与层间环境的相容性要适中；（4）聚合物乳液共混共凝法有利于传统的制备方法，适合于具有乳液形成的聚合物；（5）在聚合物中原位生成硅酸盐片层的方法具有新意；（6）层状硅酸盐／聚合物纳米复合材料的主要特点是高刚性、高强度、高耐热性、高阻隔性、较好的阻燃性、质轻，目前，该的制备研究正向所有的聚合物品种扩展。汽车部件、包装材料将是层状硅酸盐／聚合物纳米复合材料先应用的两大领域；（7）层状硅酸盐／聚合物纳米复合材料的理论研究进展延慢。界面区状态以及结构－性能间的关系是理论研究的两个主题。     

Field-assisted diffusion of potassium ions in sodium silicate glass

The kinetics of interaction between the 20Na₂O · 80SiO₂ glass and the potassium nitrate melt is investigated in the presence of a dc electric field and without it. The interdiffusion coefficients and effective electrical mobilities of potassium ions, as well as the parameters of the temperature dependence of the electrical mobility, are determined. It is established that the models describing the field-assisted diffusion processes in the framework of the Nernst-Einstein equation are not applicable to analyzing the interactions responsible for the considerable changes in the chemical composition of the diffusion zone.     

Defects in the structure and properties of silicate materials

Special features of the effect of nonequilibrium defects, including dislocations on the activity and the structural instability of silicate systems, are considered. It is shown that the physicochemical properties of a material depend substantially on the phase composition, the presence of defects in the structure, and the treatment conditions. The hydration process is shown to intensify in the early stage of the interaction between portland cement and water. The suggested model of an “absolutely deformed solid body” makes it possible to take into account the structural defects, the level of the accumulated energy, and the activity of materials in the stage of preparing the raw components and the waste and in the production cycle of various silicate materials.