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随着城市建设的快速发展,大多数旧的城市沥青道路出现网裂车辙、波浪、拥包、坑槽、啃边等各种病害,结构上日趋破坏,已不能满足功能上的需要,服务水平很低。本文针对旧沥青道路改造方案的我分析,提出在城市旧沥青道路硬化改造的设计与施工中应注意的问题。 相似文献
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杨喜林 《中国科学院研究生院学报》1981,19(2):238-244
The present paper deals with 3 genera,Pugionium Gaertn., Lepidium L. and Torula-
ria O. E. Schulz of the family Cruciferae found in the desert regions of China.
Of the genus Pugionium 4 species and 1 new variety and their geographical distribu-
tion are recognized.
Two closely related species of Lepidium, L. apetalum Willd. and L. ruderale L. and
one additional new species are described and their distribution patterns are discussed.
Two species of the genus Torularia previously described by V. Botschantzev (1959)are here redused to varietal ranks, and one additional new species is described. 相似文献
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