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MAPO-5分子筛的合成、结构及其性质的研究 总被引:3,自引:0,他引:3
用水热法合成了磷酸镁铝分子筛(MAPO-5),以X射线衍射、电子探针、核磁共振及红外光谱等方法进行了结构分析,并测定了MAPO-5分子筛的晶胞参数、化学组成,同时对分子筛的吸附性能、热稳定性、酸性等进行了研究。证明镁进入了分子筛的骨架。 相似文献
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A mag1c angle spinning system for sealed samples has been achieved with a speed from 1.5 to 4.2 kHz. Using this system, high-resolution ~1H spectra are obtained for H_2S and alcohols adsorbed on charcoal in sealed ampoules. For high coverage of alcohols, the spectral lines are resolved very well, but for low coverage, the spectral lines cannot be separated completely. The details are discussed and the solution is anticipated. 相似文献
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处理条件对Mo/HZSM-5催化剂结构及性能的影响 总被引:2,自引:0,他引:2
使用付立叶变换红外光谱和固体高分辨核磁技术,考察了在不同处理条件下,甲烷无氧芳构化催化剂Mo/HZSM5分子筛骨架结构的变化情况.结果显示,较高的焙烧温度和较高的预处理温度,都会造成催化剂中担载的钼物种对分子筛骨架铝的严重抽提,特别是在钼物种含量较高时,这种情况更明显.以不同担体及不同钼物种构成的前驱态催化剂的催化反应评价结果表明,以微晶状态存在的MoO3和与担体间以相对较弱作用力存在的高分散钼物种,在反应过程中被活化成具有催化活性钼物种的几率更大;而晶相状态的Al2(MoO4)3以及与载体间存在较强相互作用力的钼物种,在甲烷无氧芳构化过程中不起主要催化活性作用.计算得出,甲烷无氧脱氢芳构化反应的表观活化能为89.8kJ/mol. 相似文献
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For those organic compounds which lack free radicals, a doping approach named melting-liquid-nitrogen-quench was developed in order to perform dynamic nuclear polarization(DNP)-nuclear magnetic resonance experiments. By using this method, the 1H, 13C, 15N DNP enhancements were observed with free-radical-doped dibenzofuran and benzamide. The enhancement mechanism and relation between the concentration of unpaired electrons and the maximum DNP enhancement are discussed. 相似文献
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在醇法合成ZSM-5分子筛的基础上,用固体高分辨~(23)Na-MAS-NMR技术对ZSM-5分子筛原粉、灼烧以及灼烧后吸水的样品进行对比研究,结果表明,在醇法合成的ZSM-5样品中,Na~+与醇分子之间存在相互作用,与醇结合的Na~+在分子筛形成过程中起模板作用. 相似文献
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We observed the NMR signal of low-pressure gas 129Xe by laser enhanced method on an MSL-400 NMR spectrometer and measured nuclear spin relaxations of 129Xe gas at various temperatures. The relaxation rate constant of 129Xe-133Cs spin exchange was obtained as (6.8±0.5)×10-16cm-3s-1. 相似文献