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THE FORMATION AND EVOLUTION OF DUAL-NUCLEI STRUCTURE IN DELTA——BASED ON THE APEX CITY |
LI Ping-hua1,2 |
1. Center for the Yangtze River Delta's Economic and Social Development, Nanjing University, Nanjing 210093, China;
2. School of International Economics and Trade, Nanjing University of Finance and Economics, Nanjing 210046, China |
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Abstract The conception of the apex city of delta belongs to the field of economic geography, which is put forward based on the city location and the natural environment evolution of delta. It is discovered that this kind of city universally exists in many deltas. In these deltas, the apex city and the port city are connected by many types of transportation patterns, thus the dual-nuclei structure composed by these two kinds of cities is formed.
In this paper, the author points out first that the apex city-port city dual-nuclei structure is a new spatial structure. Also, this kind of spatial structure is the principal regional economic axes of the delta and the economic elements are centralized along the transportation line between the two dominating cites. And the author illustrates that the apex city-port city dual-nuclei structure is a common phenomena through contrastive case analysis on many deltas.
Also, the author in this paper, puts forward that the formation of this spatial structure is companied with the evolution of natural environment in delta, for instance, the evolution of coastline. Based on the analysis above and the known spatial centralization patterns, the author divides the formation process of the apex city -port city dual-nuclei structure into two types—— the endogenetic and the ectogenic. The development of domestic delta is driven by endogenetic force. The dual-nuclei structure composed by apex city and the port city has been developing along with the evolution of physical environment of delta, which could be dassified into five phases during this process: the germination period of cities in apex region, the competition period of apex city, the fast development period of cities in delta, the formation period of the port city and dual-nuclei structure, the maturation period of the dual-nuclei structure, and so on.
At last, the author believes that in the process mentioned above, the gateway of the delta was changed from the apex region to the coastal region, and the importance of the apex city declined gradually, compared with the port city. While in the dual-nuclei structure driven by ectogenic force, the apex city did not experience the declining and function changing process, but it was impacted by the port city originally. Therefore, there are large differences between the apex city and the port city in this type of dual-nuclei structure, such as the city's size and the importance.
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Received: 18 April 2007
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