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991.
柠檬酸溶胶-凝胶法制备的Ce1-xZrxO2: 结构及其氧移动性 总被引:1,自引:0,他引:1
采用 XRF、XRD、Raman、XPS、H2-TPR 以及与氩离子刻蚀相结合的XPS等表征技术对柠檬酸溶胶-凝胶法制备的Ce1-xZrxO2 (0≤x≤1)样品的结构及其氧移动性进行了研究. 结果表明, Ce1-xZrxO2 样品的晶型结构对其中氧的移动性有明显影响. 当x≤0.15 时, Ce1-xZrxO2 以立方CeO2相 Ce-Zr-O 固溶体存在, 随着Zr含量的逐渐增加, CeO2晶胞体积减小、氧空位浓度增加, 氧移动性逐渐增强; 当x>0.15时, 形成四方ZrO2相和立方CeO2相Ce-Zr-O固溶体的混合物, 随着Zr含量的逐渐增加, 四方ZrO2相的含量增加、氧空位浓度减小, 氧移动性逐渐减弱. 因此, Ce0.852Zr0.152O2样品具有最高的氧移动性. 相似文献
992.
通过实验,采用荧光光谱法研究了对二甲氨基偶氮苯邻羧酸(JJR)与脱氧核糖核酸(DNA)结合反应的特征.由Stern-Volmer方程和双倒数曲线Lineweaver-Burk方程获得了反应的猝灭常数Ksv=1×106~2×106 L/mol、结合常数KA≈0.5×106 mol/L以及对猝灭的类型做出了推断.通过热力学参数、离子强度实验讨论并得到它们以氢键、嵌插入、范德华力等几种方式作用.该反应的最佳实验条件为pH值控制在6.1左右;加入顺序为JJR+DNA+(B-R)适宜反应体系;线性范围在0~100 mg/L之间. 相似文献
993.
994.
Qing Jie Zhao Yan Song Hong Gang Hu Shi Chong Yu Qiu Ye Wu School of Pharmary Second Military Medical University Shanghai China 《中国化学快报》2007,18(6):670-672
Twenty-three 1 -(1H-1,2,4-triazole-1 -y1)-2-(2,4-difluorophenyl)-3-(iV-cycloproyl-N-substituted-amino)-2-propanols were designed and synthesized on the basis of the active site of lanosterol 14α-demethylase. In vitro antifungal activities showed that some of the title compounds had higher antifungal activity and broader antifungal spectrum than fluconazole. 相似文献
995.
Zhen Chen Huan Meng Hui Yuan Gengmei Xing Chunying Chen Feng Zhao Yun Wang Chengcheng Zhang Yuliang Zhao 《Journal of Radioanalytical and Nuclear Chemistry》2007,272(3):599-603
Nanosized copper particles are widely used in fields of lubricants, polymers/plastic, metallic coating and ink. Recently,
we found that copper particles in different sizes can lead to different toxicological effects. To clarify the target organs
of copper particles of different sizes, the inductively coupled plasma mass spectroscopy (ICP-MS) was employed to evaluate
the distribution of copper in different organs of mice after a single dose oral exposure. The results suggest that the main
target organs for copper nanoparticles are kidney, liver and blood. Liver is the main damaged organ. 相似文献
996.
997.
Chuan Zhou Tao Juan Li Xin Cui Yao Fu Qing Xiang Guo 《中国化学快报》2007,18(10):1199-1202
The possibility to carry out Cu-catalyzed cross-couplings under ligandless conditions was studied.It was found that by using K_3PO_4 as the base,the cross-coupling could proceed successfully between aryl iodides and several types of nucleophiles.Aryl bromides were completely inactive under the same reaction conditions. 相似文献
998.
嵌入Y型分子筛中钯簇合成与结构的研究 总被引:2,自引:0,他引:2
Pd clusters encaged in Y-zeolite (Pd0Y) have been prepared by means of exchanging zeolite HY with [Pd(NH3)4]2+ under microwave radiation. The product formed was deaminized by heating, washed sufficiently with de-ionized water and reduced with hydrogen. The crystal phase diffraction of Pd was not found in the XRD spectrogram of Pd0y. According to polycrystal X-ray diffraction data. Radial Electron Distribution Function (REDF) of Pd0Y was calculated to elucidate the structure of Pd cluster. The results show that the Pd clusters are of the Al type closely packed arrangement. The dimension of them is about 12 Å. They are encaged in the supercage of zeolite Y. Their occupancy on the supercage is as small as 0.06 so that the framework structure of zeolite Y is unchanged. Therefore, the high dispersing Pd cluster aggregating in supercage exhibit strong catalytic effect. The CO-conversion of Pd0Y with Pd 0.72% and 6.13% (in mass fraction) is 67 % and 100 % (in volume fraction) respectively. Evaluation conditions:
mixed gas containing 0.02% CO and air,
space velocity 3000 h-1,
reaction temperature 0 ℃. 相似文献
mixed gas containing 0.02% CO and air,
space velocity 3000 h-1,
reaction temperature 0 ℃. 相似文献
999.
1000.
Xiaoliu Li Yongmei Wang Daming Du Zhong Wen Guoxiang Xiong Jiben Meng 《中国科学B辑(英文版)》1997,40(3):270-277
Solid state Michael addition reaction of indole with α, β-unsaturated carbonyl compounds was carried out, by which a series
of compounds containing three different heterocyclic groups binding to one carbon atom were ob-tained. In the presence of
Lewis acid, indole could undergo the solid state condensation reaction with aromatic ketones and aldehydes or quinones. The
solid state reaction showed higher selectivity and yield than solution reaction. The structures of products were identified
by IR,1H NMR, MS. elemental analysis and X-ray crystal analysis. The reac-tion mechanism was also proposed.
Project supported by the National Natural Science Foundation of China 相似文献