Based on TM image data and other survey materials, this paper analyzed the spatiotemporal patterns of land use change in the
Bohai Rim during 1985–2005. The findings of this study are summarized as follows: (1) Land use pattern changed dramatically
during 1985–2005. Industrial and residential land in urban and rural areas increased by 643,946 hm2, of which urban construction land had the largest and fastest increase of 294,953 hm2 at an annual rate of 3.72%. (2) The outward migration of rural population did not prevent the expansion of residential land
in rural areas by 184,869 hm2. This increase reveals that construction of rural residences makes seriously wasteful and inefficient use of land. (3) Arable
land, woodland and grassland decreased at a rate of −0.02%, −0.12% and −1.32% annually, while unused land shrank by 157,444
hm2 at an annual rate of −1.69%. (4) The change of land use types showed marked fluctuations over the two stages (1985–1995 and
1995–2005). In particular, arable land, woodland and unused land experienced an inversed trend of change. (5) There was a
significant interaction between arable land and woodland. Industrial construction land in urban and rural areas showed a net
trend of increase during the earlier period, but only adjustment to its internal structure during the second period. The loss
of arable land to the construction of factories, mines and residences took place mainly in the fringe areas of large and medium-sized
cities, along the routes of major roads, as well as in the economically developed coastal areas in the east. Such changes
are closely related to the spatial differentiation of the level of urbanization and industrialization in the region. 相似文献
During the self-weight penetration process of the suction foundation on the dense sand seabed, due to the shallow penetration depth, the excess seepage seawater from the outside to the inside of the foundation may cause the negative pressure penetration process failure. Increasing the self-weight penetration depth has become an important problem for the safe construction of the suction foundation. The new suction anchor foundation has been proposed, and the self-weight penetration characteristics of the traditional suction foundation and the new suction anchor foundation are studied and compared through laboratory experiments and analysis. For the above two foundation types, by considering five foundation diameters and two bottom shapes, 20 models are tested with the same penetration energy. The effects of different foundation diameters on the penetration depth, the soil plug characteristics, and the surrounding sand layer are studied. The results show that the penetration depth of the new suction foundation is smaller than that of the traditional suction foundation. With the same penetration energy, the penetration depth of the suction foundation becomes shallower as the diameter increases. The smaller the diameter of the suction foundation, the more likely it is to be fully plugged, and the smaller the height of the soil plug will be. In the stage of self-weight penetration, the impact cavity appears around the foundation, which may affect the stability of the suction foundation.
国际海洋新秩序的形成以<联合国海洋法公约>的生效为标志.<公约>不仅赋予了沿海国对200 n mile专属经济区的主权权利等海洋权益,带来国际海洋形势的新趋势,而且会对我国海洋经济产生重要影响.<公约>的生效一方面促进了我国海洋法律的建设进程,扩大了海洋管辖;另一方面又使我国海洋经济权益受到新的威胁.专属经济区制度对我国海洋渔业生产和管理也将产生重要影响. 相似文献
New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source. 相似文献