Administrative regions are an important environment for the operation of China's market economy.The relevant economic subjects cannot predict the policy of adjustment of administrative divisions and carry out cons...Administrative regions are an important environment for the operation of China's market economy.The relevant economic subjects cannot predict the policy of adjustment of administrative divisions and carry out conscious migration behavior,adjustment of administrative divisions can be regarded as a quasi-natural experiment.The three cities of Hefei,Wuhu,and Ma'anshan,which are directly related to the adjustment of the administrative division of Chaohu,are taken as the treatment group,and the seven adjacent cities of Lu'an,Huainan,Chuzhou,Bengbu,Anqing,Chizhou,and Tongling are taken as the control group.Differences-in-Differences method and relevant control variables affecting the upgrading of industrial structure are used to test.The test results show that"Partitions of Chaohu"has a significant industrial structure upgrading effect by promoting the optimization of spatial layout,the cross-regional flow of production factors and the effective management of Chaohu Lake Basin.At the same time,the increase of total retail sales of consumer goods,urban fixed assets investment,public utility expenses in science,education,culture and health,and population plays a significant positive role in promoting the upgrading of industrial structure,while foreign direct investment plays a certain inhibition role in the upgrading of industrial structure.In order to meet the ever-developing space demands and enhance the impact on surrounding areas,the Hefei metropolitan area should be driven by technological innovation,strengthen the integration of industrial chains,improve the business environment and transportation network,and continuously promote the upgrading of industrial structure and the formation and development of new productive forces.展开更多
In this paper, an SI epidemic model with stage structure is investigated. In this model, impulsive biological control which release infected pest to the field at a fixed time periodically is considered, and obtained t...In this paper, an SI epidemic model with stage structure is investigated. In this model, impulsive biological control which release infected pest to the field at a fixed time periodically is considered, and obtained the sufficient conditions for the global attractivity of pest-extinction periodic solution and permanence of the system. We also prove that all solutions of the model are uniformly ultimately bounded. The sensitive analysis on the two thresholds and to the changes of the releasing amounts of infected pest is shown by numerical simulations. Our results provide a reliable tactic basis for the practice of pest management.展开更多
Establishing rural land collective property right system with clear ownership,complete powers and functions,smooth transfer,and strict protection is the basic guarantee to the equal exchange of land elements. In this ...Establishing rural land collective property right system with clear ownership,complete powers and functions,smooth transfer,and strict protection is the basic guarantee to the equal exchange of land elements. In this study,the reform of relevant legal systems to China's rural land transfer was introduced firstly,and then the guiding ideology of China's rural land transfer was proposed. Finally,the ways of practicing rural land transfer in China were discussed. Based on the premise of insisting on and improving the strictest land preservation system,farmers should have the right to occupy,use,and transfer their contracted land,and they can transfer their land contracting and management right in ways of exchange,subcontracting,renting,stock cooperation,and trust. Exploring the ways of equal exchange of land elements according to local conditions is an important political and economic issue concerning the livelihood and development of farmers in China,so it should be conducted under the guidance of the correct ideas to integrate scattered land in China's rural areas,develop moderate-scale management,shorten the income gap between urban and rural areas,and realize balancing development of urban and rural areas in China.展开更多
文摘Administrative regions are an important environment for the operation of China's market economy.The relevant economic subjects cannot predict the policy of adjustment of administrative divisions and carry out conscious migration behavior,adjustment of administrative divisions can be regarded as a quasi-natural experiment.The three cities of Hefei,Wuhu,and Ma'anshan,which are directly related to the adjustment of the administrative division of Chaohu,are taken as the treatment group,and the seven adjacent cities of Lu'an,Huainan,Chuzhou,Bengbu,Anqing,Chizhou,and Tongling are taken as the control group.Differences-in-Differences method and relevant control variables affecting the upgrading of industrial structure are used to test.The test results show that"Partitions of Chaohu"has a significant industrial structure upgrading effect by promoting the optimization of spatial layout,the cross-regional flow of production factors and the effective management of Chaohu Lake Basin.At the same time,the increase of total retail sales of consumer goods,urban fixed assets investment,public utility expenses in science,education,culture and health,and population plays a significant positive role in promoting the upgrading of industrial structure,while foreign direct investment plays a certain inhibition role in the upgrading of industrial structure.In order to meet the ever-developing space demands and enhance the impact on surrounding areas,the Hefei metropolitan area should be driven by technological innovation,strengthen the integration of industrial chains,improve the business environment and transportation network,and continuously promote the upgrading of industrial structure and the formation and development of new productive forces.
文摘In this paper, an SI epidemic model with stage structure is investigated. In this model, impulsive biological control which release infected pest to the field at a fixed time periodically is considered, and obtained the sufficient conditions for the global attractivity of pest-extinction periodic solution and permanence of the system. We also prove that all solutions of the model are uniformly ultimately bounded. The sensitive analysis on the two thresholds and to the changes of the releasing amounts of infected pest is shown by numerical simulations. Our results provide a reliable tactic basis for the practice of pest management.
基金Supported by the National Social Science Foundation of China in 2013(13BJY053)
文摘Establishing rural land collective property right system with clear ownership,complete powers and functions,smooth transfer,and strict protection is the basic guarantee to the equal exchange of land elements. In this study,the reform of relevant legal systems to China's rural land transfer was introduced firstly,and then the guiding ideology of China's rural land transfer was proposed. Finally,the ways of practicing rural land transfer in China were discussed. Based on the premise of insisting on and improving the strictest land preservation system,farmers should have the right to occupy,use,and transfer their contracted land,and they can transfer their land contracting and management right in ways of exchange,subcontracting,renting,stock cooperation,and trust. Exploring the ways of equal exchange of land elements according to local conditions is an important political and economic issue concerning the livelihood and development of farmers in China,so it should be conducted under the guidance of the correct ideas to integrate scattered land in China's rural areas,develop moderate-scale management,shorten the income gap between urban and rural areas,and realize balancing development of urban and rural areas in China.
