Research On The Evolution Of Innovation Network And Influencing Factors In Urban Agglomeration In The Middle Reaches Of The Yangtze River

China's economy is gradually turning to the stage of innovation-driven and high-quality development,and innovation has become the endogenous driving force of China's economic development.In recent years,the network trend of regional innovation research is obvious,and innovation network has become a new direction of innovation research.This paper analyzes the characteristics and influencing factors of innovation network of urban agglomeration in the middle reaches of the Yangtze River from the perspective of network,which can not only enrich the research content of urban innovation geography,but also provide reference for promoting the innovation collaboration and high-quality economic development of urban agglomeration in the middle reaches of the Yangtze River,therefore,it has a strong academic and practical significance.This paper takes 31 cities in the middle reaches of the Yangtze River as research samples,uses the transferring data of inter-city patent in 2008,2013 and 2018 from the Incopat and relevant socio-economic statistics to deal with the transferring legal affairs of inter-city patent with the help of the CV analysis,and constructs the innovation network of the middle reaches of the Yangtze River based on P-space model.And then,by using the methods of social network analysis,spatial analysis and QAP analysis,this paper analyzes the spatial-temporal evolution characteristics of the innovation network structure of the urban agglomeration in the middle reaches of the Yangtze River from the perspectives of point,line and plane,and explores the relevant factors that affect the formation and development of the innovation network of the urban agglomeration in the middle reaches of the Yangtze River.The conclusions are as follows:(1)The spatial heterogeneity of urban node characteristics in the innovation network of urban agglomeration in the middle reaches of the Yangtze River is significant.The innovation network patent transfer presents a central-periphery pattern with high value surrounded by low value.The degree centrality of innovation network city has a clear hierarchy and a distinct hierarchical structure,showing a pyramid structure."Three poles"including Wuhan,Changsha and Nanchang play a prominent role of "bridge",which is the"innovation hub" of the innovation network development of urban agglomerations in the middle reaches of the Yangtze River.(2)The evolution of innovation network association structure of urban agglomeration in the middle reaches of the Yangtze River is hierarchical,phased and complex.The innovation network has formed a multi-center star structure with Wuhan as the center and Changsha City and Nanchang as the sub-centers.The relationship structure of innovation network has experienced three development stages:initial stage,preliminary development stage and the perfect stage.The correlation level and form of innovation network changes from low to high,simple to complex.(3)The innovation network of urban agglomeration in the middle reaches of the Yangtze River has obvious characteristics with core-edge structure and community structure.There are fewer high-core cities and more low-core cities in the middle reaches of the Yangtze River,showing an obvious and relatively stable core-edge structure.The cities of urban agglomeration in the middle reaches of the Yangtze River are clustered into four plates:Hubei(A),Hunan(B),Jiangxi(C)and edge plate.This division is highly correlative with the provincial administrative divisions and the spatial distribution of plate members has evolved from scattered to relatively concentrated,which keeps relatively stable.The intensity and frequency of innovation links among the members of each plate are relatively high,while the patent innovation relationship among plates is relatively lack,which fails to fully break through the plate boundary restrictions.(4)The development of urban agglomeration innovation network in the middle reaches of the Yangtze River is affected by many factors.The input gap of scientific research resources,policy support,opening-up and industrial structure similarity have positive effects on the innovation network of the urban agglomeration in the middle reaches of the Yangtze River;the gap of economic development level,geographical distance,technology absorption capacity,informatization level and innovation output level have negative effects.Moreover,scientific research resource investment gap and geographical distance have a relatively stable and significant impact on the innovation network of urban agglomeration through innovation potential difference and exchange cost respectively.in the middle reaches of the Yangtze River.In order to promote the development of innovation network of urban agglomeration in the middle reaches of the Yangtze River,this paper puts forward the following suggestions:accelerating the coordinated development of innovation among urban agglomerations;strengthening the leading role of innovation in the central city like Wuhan etc;improving the intercity transportation network system of Urban Agglomeration;increasing the investment of innovation resources in low innovation cities.