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排序方式: 共有117条查询结果,搜索用时 982 毫秒
51.
R.R. Patil Ms. Rujuta BarveM.S. Kulkarni B.C. BhattS.V. Moharil 《Physica B: Condensed Matter》2012,407(4):629-634
Various fluoro-silicates, viz. M2SiF6 (M=Li, Na, K) were synthesized by reacting the mixture of corresponding salt and silicic acid with Hydrofluoric acid. The thermal analysis of these materials was performed. These materials were doped with ions Ce3+, Cu+, Ag+ and photoluminescence, TL, OSL properties were studied. Intense TL and OSL was observed from these materials. Due to decomposition during heating, these materials may not be suitable as TL Phosphors, but will be good phosphors for radiation dosimetry using OSL. 相似文献
52.
LaBaB9O16 phosphors activated by various ions belonging to ns2, 3dn and 4fn configurations were prepared by combustion synthesis. Phosphors’ synthesis and luminescence spectra are reported. Most of the activators displayed intense characteristic emission. Pr3+→Gd3+, Ce3+→Tb3+, Ce3+→Dy3+, Ce3+→Mn2+ and Bi3+→Mn2+ energy transfers were also observed. In particular, Ce3+→Tb3+ energy transfer leads to an efficient green emitting phosphor. 相似文献
53.
CaSO4 exists in several phases. The most common phase of CaSO4 is orthorhombic and reported Ce3+ emission corresponds to this phase. However, significant change in the emission of Ce3+ is observed when CaSO4 crystallizes in hexagonal phases. The emission is observed at 354 nm as compared to the spilt band at 305 and 326 nm for the orthorhombic phase. The preparation procedure and photoluminescence spectra for orthorhombic and hexagonal phases are described in this paper. 相似文献
54.
The bleaching of F-centres on storing in darkness of electrolytically coloured single crystals and microcrystalline powders of solid solutions of KBr with other alkali bromides is reported. The colouration of the microcrystalline powders decays isothermally while that of single crystals is comparatively stable. The decay proceeds slower in the powders of mixed crystals than in the pure materials. A tentative explanation is suggested. 相似文献
55.
56.
Summary The present work is an extension of an earlier study that compared the stress relaxation between two molecular masses of a bisphenol-A polycarbonate due to thermal aging. The enthalpy relaxation of the same materials has been characterized. First, by measuring the change in enthalpy loss (ΔHa) and fictive temperature (Tf) as a function of aging temperature (Ta) ranging from -25 to 120°C, using differential scanning calorimetry. For the limited aging time of 120 h, ΔHa and Tf changes were only appreciable for (Tg -70 K)<Ta<Tg . While the influence of molecular mass was somewhat discernible, enthalpy measurements were not as sensitive as stress relaxation tests in differentiating molecular mass effects. In a second investigation, the kinetics of enthalpy relaxation upon isothermal aging at 130°C was evaluated using the peak shift method and found to be comparable to literature values. The plot of ΔHa as a function of log (aging time) showed two distinct regions: a brief non-linear portion (less than 1 h aging) which is followed by a linear relationship as typically reported in the literature. In contrast to the linear region, the non-linear relaxation behaviour of the poorly aged state does not appear to be dependent on molecular mass. 相似文献
57.
Richard D. Adams Burjor Captain William C. Pearl 《Journal of organometallic chemistry》2008,693(8-9):1636-1644
The complex Re2(CO)8[μ-η2-C(H)C(H)Bun](μ-H) (1) reacts with SbPh3 at 68 °C to yield the new σ-phenyl dirhenium complex Re2(CO)8(SbPh3)(Ph)(μ-SbPh2) (4) in 72% yield. Compound 4 contains two rhenium atoms held together by a bridging SbPh2 ligand. One rhenium atom contains a σ-phenyl group. The other rhenium atom contains a SbPh3 ligand. Compound 4 was also obtained in 34% yield from the reaction of Re2(CO)10 with SbPh3 in the presence of UV–Vis irradiation together with some monorhenium products: HRe(CO)4SbPh3 (5), Re(Ph)(CO)4SbPh3 (6) and fac-Re(Ph)(CO)3(SbPh3)2 (7) in low yields. Complex 4 is split by reaction with an additional quantity of SbPh3 to yield the monorhenium SbPh3 complexes 6, 7 and mer-Re(Ph)(CO)3(SbPh3)2 (8) that contain a σ-phenyl ligand. When 4 was treated with hydrogen, the phenyl ligand was eliminated as benzene and the dirhenium complexes Re2(CO)8(μ-SbPh2)(μ-H) (10), and Re2(CO)7(SbPh3)(μ-SbPh2)(μ-H) (11), were formed that contain a bridging hydrido ligand. The doubly SbPh2-bridged dirhenium complex Re2(CO)7(SbPh3)(μ-SbPh2)2 (9) that has no metal–metal bond was also formed in these two reactions. 相似文献
58.
Julian M. Menter William S. Pearl Mitchell W. Yadven Isaac Willis 《Photochemistry and photobiology》1983,38(4):481-486
Abstract— We have developed a simple, rapid, sensitive procedure for measuring polyanionic glycosaminoglycans (GAG) in unfixed defatted lyophilizedSK–1 hairless mouse skin by means of quantitative measurement of uptake of the fluorescent dye acridine orange (AO), which was shown to be GAG-specific under the conditions of these experiments. This method is suitable for detecting and estimating elevations in steady skin GAG levels due to UV irradiation. 相似文献
59.
A construction of L. Brian Lawrence is extended to show that the -power of every subset of the Cantor set is homogeneous via a continuous translation modulo a dense set. It follows that every zero-dimensional first-countable space has a homogeneous -power.
60.