Investigation on ignition behaviors of pulverized coal particles in a tubular swirl burner

This paper intensively investigated the ignition of turbulent coal flames in a novel fully-mixed tubular swirl burner. The Nikon D300s digital camera was used to capture the statistical ignition behavior of dispersed coal particle streams in different ambiences. Meanwhile, the combustion dynamics of individual coal particles were also recorded by means of high-speed photography. Two low-rank coal samples, Hulunbel lignite and Zhundong coal, were tested in this study. The ignition delay times of coal particles in the swirl burner were compared with those in a flat-flame burner. In contrast to previous work on a laminar flat-flame burner, the current experimental results show that the turbulent ambience significantly enhances the ignition of all coal samples, which is exceptionally pronounced under high temperature and low oxygen conditions. In addition, the sensitivity analysis suggests that both the enhanced heat and mass transfer contribute to the early ignition in turbulence. The effect of elevated mass transfer coefficient turns prominent in low oxygen fraction ambience, wherein the volatile barrier effect is suppressed by the enhanced mixing process. The combined effect of turbulence favors the shifting of ignition modes to the heterogeneous-dominant region. Last but not least, the ceased volatile flame that visualized in turbulent low oxygen ambience further confirms the important role of heterogeneous ignition.     

Cu-mediated selective bromination of aniline derivatives and preliminary mechanism study

A simple and efficient bromination of aniline, aniline derivatives, and analogs have been developed. Forty three examples were given and the highest yield reached was 98%. Different substrates including substituted aniline, pyridin-amine, N-substituted aniline, N,N-disubstituted aniline, N-phenyl-amide, N-phenyl-sulfonamide, and nitrogen-containing heterocycles were all reactive and selectively generated desired bromo-products. The method can be applied to synthesize drug intermediate and quinoxaline derivatives.     

钢中残量元素As,Sn,Sb的X射线荧光光谱分析

本文介绍了用日本理学3530XRF光谱仪扫描道测定钢中痕量元素As、Sn、Sb。由于短波强大的背景破坏了检测线的线性,通过用DATAFLEX 181B背景扣除的数据处理,消除了这些影响,成功地校准了曲线。方法简单;快速;XRFS结果与化学分析一致,该法已用于炼钢的过程控制和原材料分析。     

球形生物活性玻璃作为运输载体的研究

球形纳米生物活性玻璃(BGN)含有硅、钙和磷等元素,具有可控的形貌和粒径、有序的介孔结构、较高比表面积和孔隙率、良好的生物相容性与成骨活性,已被广泛用于骨修复和牙科诊疗。BGN还可掺杂不同金属离子以增强成骨性、成血管性等,或使其具备抗菌性或生物成像能力。同时,球形、有序介孔结构、纳米级的尺寸和高比表面积有利于装载药物或生物因子并进入细胞,使其具有潜在的高负载能力和靶向治疗能力。但由于难以制备粒径较小的单分散BGN,且纳米级颗粒普遍存在团聚问题,对生物体的影响也不完全明确,所以,BGN尚不能作为临床药物载体被利用,相关的研究仍需深入。本文综述了近年来BGN的制备技术、负载能力、生物相容性和生物活性等方面研究及应用现状,并对其发展方向进行了展望。     

A General and Facile Synthesis of Novel Polysubstituted Quinazolin‐4(3H)‐ones

A simple and efficient approach to synthesize novel polysubstituted quinazolin‐4(3H)‐ones has been developed, and the key step is a sequential procedure involved iron‐mediated reduction and acid‐catalytic cyclization. The present method provides a convenient and practical strategy for the synthesis of quinazolin‐4(3H)‐one derivatives.