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21.
Defect-free zeolite NaA membranes were coated onto the surface of spherical Pt/Al2O3 particles using a two-step hydrothermal method. The structure and morphology of the synthesized composite catalysts were characterized using XRD and SEM techniques, respectively. The results indicated a layer of compact and uniform NaA molecular sieve membrane with a thickness of about 20 滋m was coated on the spherical Pt/Al2O3 particles after the two-step hydrothermal synthesis. The prepared NaA membrane coated catalysts were used in the oxidation of a mixture of CO and C2H4 to study the reactant selectivity over the coated zeolite NaA membranes. Under the optimized conditions, the oxidation selectivity for CO over C2H4 on the composite catalyst was as high as 96%. The feasible application of this composite membrane coated catalyst to the selective removal of CO in the presence of C2H4 was anticipated. 相似文献
22.
本文采用不同的预处理方法、盐酸解离时间及染色条件,对罗布麻（Apocynum venetum）和大叶白麻（Poacynum hendersonii（Hook．f）Woodson）离体根尖染色体分裂相的数目、染色体收缩程度、分散度以及着色深度进行了研究．对罗布麻和大叶白麻的核型进行了对比分析．结果表明：最佳的处理方法为：0．002mol／L8-羟基喹啉室温下处理根尖3h;卡诺液固定24h;1mol／L盐酸60℃下解离根尖15min;改良石炭酸品红染色24h后压片．罗布麻根尖染色体的核型公式：2n=2X=24=4m＋10sm＋8st＋2t;大叶白麻根尖染色体的核型公式：2n=2X=24=10sm＋12st＋2t． 相似文献