<正>通过比对研究16a的南京市远郊森林区林外定位观测的日空气相对湿度与市区观测的资料，证实城市森林区域空气湿度的年进程及月均值异常等主要遵循当地大气候的韵律。林区旷地的多年年均空气湿度值比市区大2.2，空气湿度差值主要出现在日间高温低湿期，进一步凸显了城市森林对邻近空间的补湿作用。

Ultrafiltration treatment of the ammonia sulfite pulping black liquor of wheat straw and its effects on chemical structure characteristics and physical properties were studied. The results showed that after uhrafiltration the content of lignin in retentate increased by 17.42% and the content of ash decreased by 18.22%. It was seen that the molecular weight distribution of lignin in black liquor and retentate were determined by Gel Chromatography. The molecular weight of lignin in permeate mainly concentrated in the range less than 4 950 with the occupation of 82. 86%, and the molecular weight of lignin in retentate was higher than that in black liquor. The contents of sulfonic, carboxyl, phenolic hydroxyl groups which are the main functional groups in retentate were all more than those in black liquor. Meanwhile, after uhrafihration, the retentate had better performance than black liquor as surfactant, as additive in concrete and as dispersant. Compared with black liquor, its surface tension at 1% was 54. 7 mN/m, and dropped 2.2 mN/m. Clean solution’ s fluidity improved from 70ram to 102ram. However, the performance of retentate was limited by uhrafihration so that it would be further improved by modification.