关键词: 经济联系网络, 空间格局, 中原经济区

Abstract: The Central Plains Economic Zone is an important engine of the central plains rising strategy, and it is also the strategy fulcrum of the regional coordinated development. Building a scientific and reasonable regional economic relation network is an important part of the construction of the Central Plains Economic Zone. This paper takes the CentralPlainseconomiczone as astudy area and its counties as the network nodes. The economic relation intensity among 231 nodes in 1996 and 2010 are calculated based on the gravity model. The regional quantity in the model is represented by the geometrical mean of GDP and population of the nodes. The GDP of 2010 have been deflated to the price level of 1996. The distance coefficient is represented by the shortest journey time by highway between the cities. Economic linkage network has been built in terms of the first, top5 and top10 in connecting intensity of each nodes, using the tools of GIS and method of Social Network Analysis to analyze the spatial pattern and evolutional characteristics of the network, and the analysis is mainly based on the concept of degree, degree distribution, clustering coefficient and betweenness centrality, etc. The results show that: (1) The CentralPlainseconomiczone has an unbalanced economic linkage network, and the distribution of the node degree exhibit an obvious rightward "inclined long-tailed distributions". The number of nodes with degree less than or equal to the median accounts for more than 85% of the total number of nodes, and a small number of nodes hold the absolute network power. Zhengzhou is the center of the network, while Luoyang and Handan are the sub-centers. The connectivity of the central and northern nodes is relatively strong, while measures should be taken to increase the connectivity of the eastern and southern nodes. (2) The network power gap between the central and marginal nodes is further widening, and the Gini coefficient and concentration ratios (CR1,CR5,CR10) of the node degree have increased significantly from 1996 to 2010.Thenetworkpowerofthecorenodesfurther increases, whilethe connectingabilityofthemarginalnodesdeclinesgradually. Theunbalancednetworkdevelopment is more pronounced,and this will restrain the interactional development between the CentralPlainsEconomicZone and its adjacent regions.(3) The network has a multiple hub-and-spoke structure. The correlation between the node degree and clustering coefficient is significantly negative. This proves that the nodes with high degree are the main connection objects of the adjacent nodes, while there are fewer mutual connections between the peripheral nodes. With the high degree nodes as the core, the network formed several sub-networks with hub-and-spoke structure of different levels. Zhengzhou is the primary hub, and plays as the core leading role for the entire economic zone, while Luoyang, Handan and Luohe are the secondary hubs, mainly playing the roles of leading and radiating for the surrounding cities and counties. The construction of the cross-shape development axis and "米" glyph development zone will strengthen the economic linkage between the primary hub and the secondary hub, it will also help the entire region to realize the advantageous complementarities and linkage development. (4) The broker nodes play an important intermediary role in the network connectivity, and the betweenness centrality is not only closely related to the node degree, but also influenced by its location in the network. The broker nodes in the economic linkage network of the Central Plains Economic Zone are mainly located in the Central Plains City Group, so the development of the Central Plains City Group will have significant impact on improving the whole connectivity of the network.

Key words: Central Plains Economic Zone, economic linkage network, spatial pattern