Dual-core city cluster is a special geographic feature during China's city cluster development. This paper uses synergy theory and growth polarity theory to establish a dual-core city cluster compound system, applies compound system synergy model and 2011-2017 panel data to measure the order of central city sub-system, order of port city sub-system and synergy of compound system of eastern China's four dual-core city clusters, providing references for theory and practice of such city cluster coordinated development. Results show their synergy displays a rising trend, entering an excellent coordinated developing stage, marked by high-low-low high. Orders of central city sub-system and coastal city sub-system are rising at same pace. Central city sub-system has experienced disorder to a rising order synergy, varying in the south and north that northern central city generally prevails the south during 2011 to 2017. Orders of port city sub-system do not show a conspicuous high-low-low-high trend, below the central city sub-system.

This paper uses input/output model and complex network method to analyze the correlation between regional energy flow and industrial structure in China with results showing that 8 regions are classified as energy flow in and flow out regions, with difference in their industrial energy consuming structures and an outstanding change in “input” energy structure at temporal order. Also the regional energy flows are different. This study is of reference for making policy. State shall differentiate energy net flow in region and net flow out region in carbon dioxide emission quota, which shall be aligned towards the major energy consuming industries along with their trans regional energy flow. The focus of energy saving and emission reducing regions and industries shall be on the major energy consuming industries.