Intense upconversion luminescence in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass

Structural and up-conversion fluorescence properties in ytterbium-sensitized thulium-doped novel oxychloride bismuth-germanium glass have been studied. The structure of novel bismuth-germanium glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wave numbers. The Raman spectrum investigation indicates that PbCl2 plays an important role in the formation of glass network, and has an important influence on the up-conversion luminescence. Intense blue and weak red emissions centered at 477 and 650 mn, corresponding to the transitions 1G(4) -> H-3(6) and (1)G(4) -> H-3(4), respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. This novel oxychloride bismuth-germanium glass with low maximum phonon energy (similar to 730 cm(-1)) can be used as potential host material for up-conversion lasers. (c) 2005 Elsevier Ltd. All rights reserved.

Structural and up-conversion luminescence properties in Tm (3+)/Yb3+-codoped heavy metal oxide-halide glasses

Tm3+/Yb3+-codoped heavy metal oxide-halide glasses have been synthesized by conventional melting and quenching method. Structural properties were obtained based on the Raman spectra, indicating that halide ion has an important influence on the phonon density and maximum phonon energy of host glasses. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions (1)G(4) -> H-3(6) and (1)G(4) -> H-3(4), respectively, were observed at room temperature. The possible up-conversion mechanisms are discussed and estimated. With increasing halide content, the up-conversion luminescence intensity and blue luminescence lifetimes of Tm3+ ion increase notably. Our results show that with the substitution of halide ion for oxygen ion, the decrease of phonon density and maximum phonon energy of host glasses both contribute to the enhanced up-conversion emissions. (c) 2005 Elsevier B.V. All rights reserved.

Comparative investigation of up-conversion luminescence in Tm3+/Yb3+-codoped germanate-niobic and germanium-bismuth glasses: effect of phonon density on up-conversion emission

Tm3+/Yb3+-codoped gernianate-niobic (GN) and germanium-bismuth (GB) glasses have been synthesized by conventional ruching and quenching method. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions (1)G(4)->H-3(6) and (1)G(4)->H-3(4), respectively, were observed at room temperature. The possible Up-conversion mechanisms are discussed and estimated. GN glass showed a weaker up-conversion emission than GB glass, which is inconsistent with the prediction from the difference of maximum phonon energy between GN and GB glasses. In this paper, Raman spectroscopy was employed to investigate the origin of the difference in up-conversion luminescence in the two glasses. Compared with phonon side-band spectroscopy, Raman spectroscopy extracts more information including both phonon energy and phonon density. For the first time, our results reveal that, besides the maximum phonon energy, the phonon density of host glasses is also an important factor in determining the up-conversion efficiency. (c) 2005 Elsevier Ltd. All rights reserved.

Intense upconversion luminescence in ytterbium-sensitized thullum-doped oxychloride germanate glass

Structural and upconversion fluorescence properties in ytterbium-sensitized thulium-doped oxychloride germanate glass have been studied. The structure of oxychloride germanate glass was investigated by peak-deconvolution of Raman spectrum, and the structural information was obtained from the peak wavenumbers. The Raman spectrum investigation indicates that PbCl2 plays an important role in the formation of glass network, and has an important influence on the upconversion luminescence. Intense blue and weak red emissions centered at 477 and 650 nm, corresponding to the transitions (1)G(4) ->(3) H-6 and (1)G ->H-3(4), respectively, were observed at room temperature. The possible upconversion mechanisms are discussed and estimated. Intense upconversion luminescence indicates that oxychloride germanate glass can be used as potential host material for upconversion lasers. (c) 2004 Elsevier B.V. All rights reserved.

离子辅助沉积中离子束流密度的作用

测量了End-Hall离子源在不同条件下的离子束流密度，在不同离子束流密度下进行了心离子辅助沉积ZrO2薄膜的实验，研究了离子束流密度对薄膜折射率、晶相的影响．根据动量传递模型分析了离子束流密度对薄膜折射率的作用；根据热尖峰理论证明了一定条件下离子束流密度不会影响薄膜晶体结构。

生长素水平以及光敏色素基因表达与水稻生殖生长的关系

第一部分 光敏核不育水稻农垦58S花药IAA的免疫组织化学分析 光周期敏感核不育水稻农垦58S是研究光周期调节花发育作用机理的好材料。在此方面已取得很大进展。有关植物激素的研究已发现长日照诱导农垦58S不育的信号传导环节之一是IAA的亏缺。本文首次应用免疫组织化学分析方法对长日和短日处理后的农垦58S和对照农垦58花药中的IAA进行了定位研究和相对水平的比较。结果表明此方法可反映游离态IAA在花药中的分布及其相对水平的变化。从雌雄蕊原基形成期至单核晚期的五个时期中，经长日照处理的农垦58S花药中的IAA水平都低于短日照处理的农垦58S及在不同光周期处理下的家垦58花药。对花药中生长素的亏缺与育性的关系以及IAA亏缺的原因也进行了讨论。 第二部分 不同水稻品种成花诱导阶段光周期敏感性及光敏色素mRNA丰度的比较 对光敏核不育水稻十多年的研究表明，光敏色素是感受光周期信号调节水稻成花诱导和育性转换的主要光受体。同时还发现光敏核不育基因导入不同遗传背景后，其基因表达条件，如临界光长、光敏温度范围、光温互补作用强弱等都表现明显差异。为了进一步探讨水稻光周期反应的作用机理，了解不同品种遗传背景对光周期信号感受的特点，我们选取籼稻、粳稻、早熟、晚熟共11个品种，比较光照阶段在长同、短同条件下叶片光敏色素B mRNA含量的差异。初步结果表明，光敏色素B的转录不受光调控，在长日、短日处理条件下没有明显差别。在多数品种间光敏色素B表达没有明显差异，说明其与品种感光性、籼粳性无明显相关。只有早熟粳稻铁粳23的光敏色素B mRNA含量较高，是一个例外。实验结果尚需进一步重复。这方面的工作可以为水稻发育光温互作本质的研究积累一些初步资料。