<正>分析南京市国家气象站和其城市森林林区外（定点）气候站16a的降水日记录资料，从月降水日数、各月最多一日降水量、暴雨等方面研究了南京城市森林的降水特征。结果表明：多年平均降水日数是林区少于市区7.3d。两站各月最多一日降水强度按级分布的年变化趋势一致，且11至3月时期，各月日最大降水级可达大雨，中雨级的百分率为林区大干市区，而小雨级则相反。4～10月的各月都可能发生暴雨级降水，两测站暴雨发生的次数及雨量都无明显的差异。

The very good method to analyze the structural change of reaction process of UF resin synthesized by the traditional process alkali-acid-alkali is 13C-NMR,and it may extrapolate the possible reaction. The structure analysis indicated that, under alkalinity condition, formaldehyde and urea reacted by addition reaction was primary. The reaction production was mainly monomethylolurea. The urea participated in the reaction completely. The formaldehyde this time still had existence by polymerization, at the same time had the occurrence of polycondensation reaction. At the acid reaction stage the polycondensation reaction was primary and formed the macro molecule system with the methylene or the ether linkage, and the polymerization formaldehyde decomposed completely, and as the form of methylene glycol participated in condensation reaction. The third urea joined may obviously reduce the free formaldehyde content of the reacting system, at the same time the reaction production was mainly monomethylolurea.