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There is huge spatial disparity between Chinese electricity production and consumption. Most of coal, hydropower, wind and solar power resource are distributed in western provinces while population and industrial activities are agglomerated in eastern provinces, which lead to a huge amount of inter-provincial electricity flow and trade to realize supply-demand balance. Based on the annual reports of the State Power Market Trading and the China Energy Statistical Yearbook, etc., this paper established the inter-provincial electricity OD flow matrix for 2006 and 2015 with a degree of interpretation over 95%. Then, taking the influence, extroversion, acceptability and dependence degree as main indicators, this paper analyzed the scale and strength of output and input points of 25 provincial administrative units and 2 regional units in China. The source and sink points of the inter-provincial electricity flow were determined, their field characteristics were studied, and the differences between the two years of 2006 and 2015 were compared. Further, the characteristics and changes of the spatial structure of inter- provincial electricity network were analyzed with the method of network analysis. At last, some conclusion can be drawn as follows. Firstly, with the development of coal-fired and wind-based clean energy bases in the northwest region and the vigorous development of hydropower resources in the southwest region, the surplus of electricity in the western region has grown rapidly. China's electricity source points gradually shifted from the central to the western region and more concentrated in southwest region. Inner Mongolia, Sichuan and Yunnan became the top three source points of Chinese electricity flow with the proportions of outward electricity to total being more than 10%. Also, their proportions of outward electricity to production were all more than 30%, which means that nearly one-third of electricity was produced for other users. On the other hand, three most prosperous metropolitan regions in China, namely Beijing-Tianjin-Hebei, Shanghai-Jiangsu- Zhejiang and Guangdong, were still the main sink points with their proportions of inward electricity to total being more than 20%. Secondly, the spatial disparities of the electricity production and consumption increased, leading to the increase of sizes of the source output and the sink input. Also, the scale of inter- provincial electricity flow and network contact density showed an increasing trend. During this period, the size of interprovincial electricity flow increased 3.1 times and the inward electricity flow of Jiangsu- Shanghai- Zhejiang, Guangdong and Beijing-Tianjin-Hebei increased 5.0, 3.4 and 2.3 times, respectively. Thirdly, the inter-provincial power flow field presented a significant three-channel pattern of "West- to-East Power Transmission" from north to south, which was affected by geographical location and subordinate regional power grids. From 2006 to 2015, this pattern of three major channels remained unchanged. Further, with the development and application of UHV technology in China, long-distance power transmission became possible so that some large electricity input points can rely on multiple sources of power instead of a single source. Therefore, the inter-provincial electricity network tends to be perfect and balanced in the future. [ABSTRACT FROM AUTHOR]

The construction of high- speed rail in China improves the comprehensive transportation systems significantly, while challenging the development of domestic air transportation at the same time. Based on the timetable data from 2007 to 2014, the overlapping market of HSR and air network is identified from the perspective of direct connection between city pairs. In 2007, the overlappping network only had 21 city pairs with direct flights and highspeed trains, and the number dramatically increased to 277 in 2014. This paper first analyzes the potential influence of HSR development on airlines and its spatial distribution. Then, a random effect regression model is established to measure the ex- post effects of the entry of HSR on air passenger flows of all the 277 city- pairs, among which, 94 city- pairs connected with the three hub cities, and 183 city-pairs connected with other feeder airports in China. The results are as follows: (1) Despite the fact that HSR and air transportation systems in China are developing in parallel, the entry of HSR has caused a modal shift from air transportation. The reduction on air travel demand caused by G trains is more obvious than that of D trains. (2) The air travel demand between inter-cities within the same or nearby provinces decreases sharply. (3) Distance, GDP, and rank of airports are significant positive factors in increasing air travel demand. (4) Due to various flight networks, preference for air transport, and sensitivity to travel time in hub cities, city pairs connected with Beijing, Shanghai or Guangzhou are more competitive for air transportation than for HSR. [ABSTRACT FROM AUTHOR]

Taking urban agglomeration as the main object to optimize the spatial layout of urbanization is an important part of constructing the national land spatial planning system, and the essence of spatial optimization is to promote the coordinated development of large, medium and small cities within the urban agglomeration. Based on the measurement of urbanization coordination level of 26 cities in the Yangtze River Delta Urban Agglomeration from 2001 to 2016, this paper analyses and identifies the urban coordination relationship by using the methods of social network and multi- dimensional- scaling, and explores its internal evolution mechanism. The results show that: (1) With the improvement of the urbanization coordination level of the cities in the Yangtze River Delta Urban Agglomeration, the internal space of the urban agglomeration is obviously changed. The high coordination cities gradually show a Zshaped distribution with Shanghai as the core, and the low coordination cities were stably distributed in the expanded area of the urban agglomeration. (2) According to the correlation strength of the coordination level of the Yangtze River Delta Urban Agglomeration, the cohesive subgroups were divided. The values of weighted average centrality and the contact density of the cohesive subgroups of the urbanization coordination relationship increased, and the polarization effect of Shanghai was more obvious. (3) The coordination structure of the urban agglomeration was identified from two dimensions of space and time. The Yangtze River Delta Urban Agglomeration has transformed from the "circle layer" structure centered on the provincial capital cities under the influence of spatial distance into the structure of "coreperiphery" under the influence of temporal distance. (4) The evolution of spatial structure of the urban agglomeration was influenced by the change of coordination level of population, land and economy urbanization. Compared with population and economy urbanization, land urbanization has a significant role in promoting the level of urban coordination. The optimizing policies of the Yangtze River Delta Urban Agglomeration were proposed from the perspective of coordination after analyses of its spatial structure. This is conducive to the realization of the integration of urban agglomeration and the efficient use of space resources under the conditions of China's existing resource and environmental carrying capacity. [ABSTRACT FROM AUTHOR]