Five title compounds were synthesized and characterized by UV Vis, IR, elemental analysis, 1H NMR and fluorescence spectra. It is found that the fluorescence intensities of the compounds at optimum pH values were 16 t...Five title compounds were synthesized and characterized by UV Vis, IR, elemental analysis, 1H NMR and fluorescence spectra. It is found that the fluorescence intensities of the compounds at optimum pH values were 16 to 319 times as much as that of 4 aminoantipyrine. The influences of the substituents of the compounds on the fluorescence intensity have been discussed.展开更多
文摘Five title compounds were synthesized and characterized by UV Vis, IR, elemental analysis, 1H NMR and fluorescence spectra. It is found that the fluorescence intensities of the compounds at optimum pH values were 16 to 319 times as much as that of 4 aminoantipyrine. The influences of the substituents of the compounds on the fluorescence intensity have been discussed.
文摘联机分析处理OLAP(online analytical processing)查询作为一种复杂查询,当使用SQL(structured query language)语句来表述时,通常都包含多表连接和分组聚集操作,因此提高多表连接和分组聚集计算的性能就成为ROLAP(relational OLAP)查询处理的关键问题.提出一种基于分组序号的聚集算法MuGA(group number based aggregation with multi-table join),该方法充分考虑数据仓库星型模式的特点,将聚集操作和新的多表连接算法MJoin(multi-table join)相结合,使用分组序号进行分组聚集计算,代替通常的排序或者哈希计算,从而有效地减少CPU运算以及磁盘存取的开销.算法的实验数据表明,提出的MuGA算法与传统的关系数据库聚集查询处理方法以及改进后的基于排序的聚集算法相比,性能都有显著提高.
