乙炔/空气预混火焰法合成多壁碳纳米管的实验研究

本文利用乙炔-空气预混火焰研究了多壁碳纳米管(MWCNTs)的合成,采用涂覆有二茂铁或硝酸镍催化剂的探针在预混火焰中采样,用扫描电镜(SEM)和透射电镜(TEM)对碳纳米材料(CNTs)的形貌和结构进行了表征.结果表明在乙炔-空气预混火焰中,二茂铁和硝酸镍均能够成功合成竹节状多壁碳纳米管,严物中处发现了碳纤维(CNF)、巴基葱(bucky onion)和碳黑等物质.二茂铁催化生成的碳纳米管管径大于硝酸镍催化生成的碳纳米管的管径;在乙炔-空 气散火焰和甲烷-空气扩散火焰中硝酸镍所催化合成的碳纳米管管径相近,说明碳纳米管的管径受催化剂颗粒尺寸的影响较大.研究表明探针在火焰中停留的时间和保护气体也会影响碳纳米管的合成.     

Numerical study on the gas heating mechanism in pulse-modulated radio-frequency glow discharge

The gas heating mechanism in the pulse-modulated radio-frequency(rf) discharge at atmospheric pressure was investigated with a one-dimensional two-temperature fluid model. Firstly, the spatiotemporal profiles of the gas temperature(T_g)in both consistent rf discharge and pulse-modulated rf discharge were compared. The results indicated that T_gdecreases considerably with the pulse-modulated power, and the elastic collision mechanism plays a more important role in the gas heating change. Secondly, the influences of the duty cycle on the discharge parameters, especially on the T_g, were studied.It was found that T_gdecreases almost linearly with the reduction of the duty cycle, and there exists one ideal value of the duty cycle, by which both the T_gcan be adjusted and the glow mode can be sustained. Thirdly, the discharge mode changing from α to γ mode in the pulse-modulated rf discharge was investigated, the spatial distributions of T_gin the two modes show different features and the ion Joule heating is more important during the mode transition.     

稀土金属有机框架的合成及其研究进展EI北大核心CSCD

稀土金属有机框架(RE-MOFs)由于其独特的性质(例如发光、磁性和固有的孔隙率)被引起了广泛研究者的兴趣。稀土离子各种电子结构有助于RE-MOFs材料在生物医学方面(例如治疗试剂和临床诊断)的应用。本篇综述旨在突出RE-MOFs纳米晶体的合成及其在临床适应性方面的研究进展;特别是基于对相关文献的研究,探索出了RE-MOFs在药物输送、荧光/磁共振成像和生物医学传感领域潜在的效用。最后讨论了RE-MOFs在生物医学领域方面安全有效利用的设计策略,并为RE-MOFs的发展提出了挑战和未来前景。