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71.
We report a newly found strong disturbing effect orAl addition to the intensity ratios of blue and green emissions from single host full-colour phosphor of Ba3MgSi2-xAlxO8:0.02Eu^2+, 0.1Mn^2+ for near-UV excited white light. The phase-pure silicate phosphor in the size of around 4μm is prepared by salt-assisted spray pyrolysis route, having three-colour emissions at the wavelength peak values of 437nm, 500 nm and 608 nm simultaneously under the excitation of 375 nm. The amount variation orAl ion added to the phosphor host results in a drastic change of the intensity ratio between green and blue emissions, while the intensity of red light keeps unchanged. As a consequence, the combination of three colours lies in the white light region and can be tuned by precisely controlled addition oral content. The Raman spectroscopy verifies the modifying effect oral ion to the tetrahedral network in silicate hosts. We assume that by addition of Al ion, the amount of those two kinds of Eu^2+ substituting for those two kinds of Ba^2+ lattice sites with distinct energy levels of blue and green featured emissions can be adjusted to contribute to diversification of the ratios of blue and green emissions. 相似文献
73.
The carbonization treatment was employed to the sugar-coated B powders before it mixed with Mg powders. It is found that the pre-carbonization treatment could effectively suppress the formation of MgO and Mg2C3 impurity in the sugar-doped samples and thus result in an improved Jc at low fields in the sugar-doped samples. Besides, the sintering process of sugar-doped samples was also investigated combined with the thermal analysis and it is found that the sugar addition could obviously lower the onset temperature of the solid–solid reaction between Mg and B. 相似文献
74.
聚缩醛螺胞二醚的合成及结构表征 总被引:3,自引:0,他引:3
在I2催化剂的作用下, 利用苯甲醛与季戊四醇反应, 制备了聚缩醛螺胞二醚的模型化合物3,9-二苯基-2,4,8,10-四氧杂螺[5.5]十一烷(1). 在此基础上, 利用1,3-苯二甲醛与不同摩尔比的季戊四醇合成了化合物1,3-二(2,6-二氧杂-4,4-二羟甲基环己基)苯(2)和2,4,8,10-四氧杂-3,9-二(3'-甲酰基苯基)螺[5.5]十一烷(3). 化合物2与化合物3反应, 制成标题化合物聚缩醛螺胞二醚4, 收率为95.4%. 用FTIR, 1H NMR对化合物1~4的结构进行了表征. 发现在含有手性轴化合物1, 3, 4的1H NMR谱中, 4个亚甲基中的8个氢原子裂分为4组双峰, 而不含有手性轴化合物中的4个亚甲基中的8个氢原子不裂分, 是个单峰. 这种不同不是由于化合物中刚性环所致, 而是由于有无手性轴造成的. 相似文献
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LIU Xiu-jie WANG Song-qing ZHANG jing ZHANG Feng-xia LI Gui-zhu WANG Bao-jie SHAO Ying-lu ZHANG Li-guang FANG Lin CHENG Mao-sheng 《高等学校化学研究》2006,22(3):356-359
Introduction Themeritsofantiplatelettherapyforthepreven tionofthrombosisincardiovasculardiseaseareevi dent.Meta analysisresultshaveshownthatsecondary preventionbyantiplateletaggregationagentscanreduce theriskofnonfatalmyocardialinfarction(MI)and strokeby2… 相似文献
78.
研究了一种新型的稀土金属铕配合物EuL1L2的光致发光和电致发光特性。将这种铕配合物掺杂到PVK:PBD中,制备成结构为ITO/PVK:PBD:EuL1L2/PBD/Alq3/Mg:Ag/Ag的器件,对其电致发光性能进行研究,发现Eu3+离子和Alq3的相对发光强度随PVK:PBD:EuL1L2和Alq3之间的激子阻挡层PBD的厚度变化而变化,通过调节PBD的厚度,得到了色纯度较高的红色电致发光器件,其光谱具有显著的Eu3+离子的光谱特征。 相似文献
79.
The temperature dependence of the optical properties in poly [2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) blending with 2-(4-biphenyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD) has been investigated. The blending influence on the chain conformation and exciton energy migration in blend film is described. The PL emission from the pure and blend films are all blue shifted with increasing temperature. An addition of PBD in MEH-PPV films suppresses the relative intensity of 0-1 vibronic peaks at lower temperature. This phenomenon will not be promoted with increasing temperature, attributed to a temperature-dependent migration process of singlet excitons. 相似文献
80.