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61.
Tb3+ ions were incorporated in P-Si matrix material through a sol-gel process. Luminescence properties of Tb3+ as a function of dopant, firing temperature, composition and structure of matrices were investigated. The gels synthesized by the reaction of P2O5 or H3PO4 with tetraethoxy silane and TbCl3 as dopant were fired in air from the temperature 25~1000℃ to form P-Si crystalline phase. The crystal structure was determined by powder X-ray diffraction. Si5O(PO4)6 were the only crystalline phase and belong to hexagonal crystal system. The emission of 5D4-7F5(~545nm) transition of Tb3+ in the P-Si system is composed of two peaks. The amount of doping Tb3+ varied from 0.664% to 1.644%, and no obvious concentration quenching was observed in this doping concentra-tion range. The intensity of Tb3+ emission increased with firing temperature increasing and becomes stable at 800~1000℃. 相似文献
62.
Eu3+掺杂SiO2-B2O3-NaF玻璃的制备及发光性质 总被引:1,自引:0,他引:1
The Eu-doped SiO2-B2O3-NaF glass was prepared by sol-gel process, using tetraethoxy Silicane, boric acid and sodium fluoride as starting materials, 0.10 mol·L-1 EuCl3 solution as the dopant. The luminescent properties of Eu3+ doped SiO2-B2O3-NaF phosphors were investigated. The phosphors showed prominent luminescence in pink, the strong emission of Eu3+ comes from electronic transition of 5D0- 7F1(591 nm)and 5D0- 7F2(615 nm),which derived from two transition modes of magnetic-dipole and electric-dipole .The peak intensity of 591nm in SiO2-B2O3-NaF matrix is much stronger than it in the other matrixes, it means that SiO2-B2O3-NaF has sensitization on the transition of 5D0- 7F1 (Eu3+). If there are broad bonds in the range of 275~380 nm in the excitation spectrum of Eu3+ -doped SiO2-B2O3-NaF glass, the emission peak intensity should be intensified. It is because the electron migration CT band of O2--Eu3+. For all Eu3+ concentrations used, the investigation found that when the mass of fraction got to 29.19×10-3, the luminescence intensity reached the summit. And there is a phenomenon of concentration quenching. Investigation with the same concentration of Eu3+ at different annealed temperature, we found that the sample annealed at 400 ℃, the luminescence intensity achieved its maximum value, and Eu3+ in this matrix had a phenomenon of temperature quenching. The structural characterization of these luminescent materials was carried by used XRD and TEM. The result showed that the phosphor was in amorphous phase. 相似文献
63.
The demonized water was added to the alkali metal salts of 2-ethythexyl phosphonic acid mono 2-ethylhexyl ester (HA) to form microemulsion of W/O type. The maximum contents of H2O in these systems reached up to the mole ratio (H2O/MA+HA) of 6.5(Li), 12 (Na) and 66 (K), respectively. They are stable when the temperature is lower than 65℃ and no water separation was observed in the ultracentrifuge under 30000r?min-1. Their electrical conductance and infrared spectra in the range of 800-4000cm-1 were studied. The variation of stretching absorption peaks of P=O, P-O-C and P-O-H and their oscillator strengths with the amount of H2O added have been recorded. 相似文献
64.
A series of D-π-A type sulfonium salt photoacid generators with different π-conjugated structures, such as triphenyl, phenylstilbene, styryl-biphenyl, and stilbene, were designed to determine the effect of molecular structures on the photochemical and photophysical properties. The mechanisms of photochemical generation of H+ were studied by UV-Vis spectroscopy, theoretical calculations, and fluorescence spectroscopy. It is found that the frontier orbits determine the absorption, the molar extinction coefficients, and the quantum yields of photoacid generation. Triphenyl systems connected with sulfonium are beneficial to increase the quantum yields of acid generation. The photoreactivity of four sulfonium salts was further evaluated through the polymerizations of various epoxide monomers at different irradiation wavelengths (365–425 nm) by using the real-time infrared spectroscopy with light-emitting diodes. The high quantum yields for acid generation (Φ H + = ~0.32 to 0.58) and the high molar extinction coefficients (ε = ~23500 L?mol?1?cm?1 to 31000 L?mol?1?cm?1) of the sulfonium salts lead to high conversion rates (over 50%–80%). Hence, these photoinitiators exhibit potential for the photocuring applications. 相似文献
65.
Baoliang Lva b Yao Xua Bo Houa Dong Wua Yuhan Suna a State Key Laboratory of Coal Conversion 《中国颗粒学报》2009,7(3)
Zr/ZrH2 particles with irregular morphologies and broad size distribution were uniformly coated with acicular-FeOOH crystal grains via a facile route without using polymers or surfactants. The as-synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), UV-vis diffusion reflection (UV-vis) and Raman spectrometry. Based on these characterizations, the synthesis mechanism was explained in terms of combined heterogeneous nucleation and... 相似文献
66.
Yi Lua Xingwang Zhanga Jie Laib Zongning Yinb Wei Wua a School of Pharmacy Fudan University Shanghai China b West China School of Pharmacy Sichuan University Chengdu China 《中国颗粒学报》2009,7(1)
Meloxicam-β-cyclodextrin (ME-β-CD) inclusion complex was prepared by a fluid-bed coating technique upon solvent removal and simultaneous depositing onto the surface of nonpareil pellets and using PVP K30 as a binding agent to facilitate good coating. The resultant pellets were spherical and intact in shape with good flowability and friability. SEM analysis showed that the pellets were smooth and had a tightly coated inclusion complex layer. In vitro dissolution of the inclusion complex pellets in pH 7.4 pho... 相似文献
67.
68.
电解质对纳米银胶水溶液光谱行为的影响 总被引:1,自引:0,他引:1
纳米粒子因为具有量子尺寸效应和表面效应等特性而显示出体相材料不具备的各种性质[1] .贵金属纳米材料因其特有的光电磁性质、催化特性以及在微电子学领域中的潜在应用前景而成为纳米材料科学领域中的热点之一 [2~ 4 ] .纳米银胶粒子的表面性质对材料的性质和应用具有重要影响 .常用谱学手段研究纳米银胶的表面特性[5~ 7] .纳米银胶颗粒表面电子云的等离子体共振效应导致了银胶在紫外 -可见光谱上的特征吸收 ,而且吸收峰的峰形会受纳米银胶粒子的大小、分散溶剂及表面吸附分子等因素的影响 [8,9] .Arnim Henglein等 [9~ 11]系统研究了… 相似文献
69.
正常与癌症肺组织的傅里叶变换红外光谱差异的研究 总被引:5,自引:0,他引:5
傅里叶变换红外(FTIR)光谱可以在分子水平上研究细胞和组织等复杂的生命体系,提供分子结构和组成的信息.我们发展了一种用于直接测定肿瘤及正常组织红外光谱的方法,对16例肺癌及其癌旁正常组织进行了测定.结果表明,对于正常和癌变的肺组织,FTIR光谱中存在显著差异,相关谱带的相对峰高比可以表征这些差异.因此,傅里叶变换红外光谱可以用来诊断癌症与正常的肺组织,有望成为肿瘤快速诊断的新方法. 相似文献
70.
N1923从碱性氰化液中萃取金(Ⅰ)的研究 总被引:6,自引:0,他引:6
采用放射性同位素198Au示踪法研究了伯胺N1923和TBP从碱性氰化液中萃取金(Ⅰ),考察了酸化率、水相pH值、萃取剂浓度等对萃取率的影响,以及NaOH对载金有机相的反萃作用。结果表明,TBP含量大于20%,酸化的N1923与KAu(CN)2摩尔比值在11时,金能够完全被萃取。载金有机相可采用0.1mol·L-1的NaOH溶液定量反萃。机理研究表明,伯胺和TBP萃取Au(CN)2-,符合BC类协同萃取机理。当金浓度大于10g·L-1时,在萃取有机相中形成纳米级的聚集体。 相似文献