Using the ‘theoretical hypothesis—empirical study—case verification' method, this paper studies the spatial distribution and differentiation of port & shipping service enterprises(PSSE), as well as the vari...Using the ‘theoretical hypothesis—empirical study—case verification' method, this paper studies the spatial distribution and differentiation of port & shipping service enterprises(PSSE), as well as the variation process and underlying mechanism in the Yangtze River Delta(YRD). First, through inductive and deductive reasoning, we propose the following hypothesis: the regional distribution of different types of PSSE would show different spatial agglomeration-decentralization tendency; and there would be distinct regional differentiation in the industrial structure of the enterprises. Second, based on data obtained from enterprises, empirical research is conducted using Gini coefficient and spatial interpolation simulation methods. Results show that: 1) The overall enterprise distribution is decentralized within a city. 2) Different types of enterprises show different spatial agglomeration-decentralization tendencies. At 3000 m×3000 m grid scale, there is an agglomeration tendency along seas and rivers in the spatial distribution of enterprises. Shanghai has been identified consistently as a hot spot. 3) There is significant regional differentiation in 12 port cities with respect to the industrial structures of enterprises. Finally, the transportization and the increase of shipping service demand, the globalization and the expansion of multinational corporate activities, the hierarchization and the cooperation among port cities as well as the decentralization and the behavioral difference between the central and local states can be seen as main driving mechanism of the spatial phenomenon.展开更多
针对低碳新能源供能与电热气负荷间能量平衡困难及其时空不确定性,提出一种基于交通流和多源能量流协同的城市多能源系统移动能量枢纽(mobile energy hub, MEH)模型及规划方法。首先,研究低碳型高比例可再生能源供能的城市多能源系统源...针对低碳新能源供能与电热气负荷间能量平衡困难及其时空不确定性,提出一种基于交通流和多源能量流协同的城市多能源系统移动能量枢纽(mobile energy hub, MEH)模型及规划方法。首先,研究低碳型高比例可再生能源供能的城市多能源系统源网荷能量和功率平衡及其调节需求特性,建立具有灵活的“电-气-氢”能源转换和存储特性的移动能量枢纽模型;其次,基于移动能量枢纽模型,综合考虑交通运输网络流量动态及其输运成本,建立基于交通网与城市多能源系统网络协同和移动能量枢纽能量特性的多能流时空协调模型;然后,考虑可再生能源出力以及负荷不确定性,提出城市多能源系统不确定性模型,并在此基础上建立了综合投资和运行成本最小的移动能量枢纽规划模型;最后,以我国北方某地区多能源系统运行数据为基础,建立移动能量枢纽仿真模型。算例仿真结果表明,该文提出的移动能量枢纽规划模型能够有效提升城市多能源系统维持较高能量平衡水平下的经济性,并可为较大供能规模的多能源网络提供较好的多时空尺度能量调节特性。展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41771139,41671132,41801111)Natural Science Foundation of Jiangsu Province(No.BK20171516)Natural Science Foundation of Zhejiang Province(No.LY18D010004)
文摘Using the ‘theoretical hypothesis—empirical study—case verification' method, this paper studies the spatial distribution and differentiation of port & shipping service enterprises(PSSE), as well as the variation process and underlying mechanism in the Yangtze River Delta(YRD). First, through inductive and deductive reasoning, we propose the following hypothesis: the regional distribution of different types of PSSE would show different spatial agglomeration-decentralization tendency; and there would be distinct regional differentiation in the industrial structure of the enterprises. Second, based on data obtained from enterprises, empirical research is conducted using Gini coefficient and spatial interpolation simulation methods. Results show that: 1) The overall enterprise distribution is decentralized within a city. 2) Different types of enterprises show different spatial agglomeration-decentralization tendencies. At 3000 m×3000 m grid scale, there is an agglomeration tendency along seas and rivers in the spatial distribution of enterprises. Shanghai has been identified consistently as a hot spot. 3) There is significant regional differentiation in 12 port cities with respect to the industrial structures of enterprises. Finally, the transportization and the increase of shipping service demand, the globalization and the expansion of multinational corporate activities, the hierarchization and the cooperation among port cities as well as the decentralization and the behavioral difference between the central and local states can be seen as main driving mechanism of the spatial phenomenon.
文摘针对低碳新能源供能与电热气负荷间能量平衡困难及其时空不确定性,提出一种基于交通流和多源能量流协同的城市多能源系统移动能量枢纽(mobile energy hub, MEH)模型及规划方法。首先,研究低碳型高比例可再生能源供能的城市多能源系统源网荷能量和功率平衡及其调节需求特性,建立具有灵活的“电-气-氢”能源转换和存储特性的移动能量枢纽模型;其次,基于移动能量枢纽模型,综合考虑交通运输网络流量动态及其输运成本,建立基于交通网与城市多能源系统网络协同和移动能量枢纽能量特性的多能流时空协调模型;然后,考虑可再生能源出力以及负荷不确定性,提出城市多能源系统不确定性模型,并在此基础上建立了综合投资和运行成本最小的移动能量枢纽规划模型;最后,以我国北方某地区多能源系统运行数据为基础,建立移动能量枢纽仿真模型。算例仿真结果表明,该文提出的移动能量枢纽规划模型能够有效提升城市多能源系统维持较高能量平衡水平下的经济性,并可为较大供能规模的多能源网络提供较好的多时空尺度能量调节特性。
