Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern Ch...Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.展开更多
经颅直流电刺激(transcranial direct current stimulation,tDCS)和神经肌肉电刺激(neuromuscular electrical stimulation,NMES)作为两种非侵入性干预手段,常被用于提升人体运动能力。而目前尚无同时使用这两种电刺激手段,改善神经肌...经颅直流电刺激(transcranial direct current stimulation,tDCS)和神经肌肉电刺激(neuromuscular electrical stimulation,NMES)作为两种非侵入性干预手段,常被用于提升人体运动能力。而目前尚无同时使用这两种电刺激手段,改善神经肌肉控制能力,提高健康人群运动表现的相关研究。以专业赛艇运动员为研究对象,通过在专项测试前的热身阶段联合使用tDCS和NMES,观察其对赛艇运动表现的即时性影响。结果表明:tDCS+NMES可显著提高受试者500 m全力测功仪测试的平均功率(P<0.05);在100 m全力测功仪测试中,实验组受试者股四头肌肌电RMS显著高于对照组(P<0.05);背阔肌肌电频域指标选取平均功率频率(mean frequency,MNF)和中值频率(median frequency,MDF)显著高于对照组(P<0.05)。在500 m全力测功仪测试中,实验组受试者股四头肌肌电iEMG显著高于对照组(P<0.05),股四头肌和背阔肌肌电的MNF和MDF也显著高于对照组(P<0.05)。可见:在热身阶段使用tDCS+NMES可有助于提升赛艇运动员神经肌肉动员能力,提高主要发力肌肌纤维募集程度,从而改善赛艇运动表现;tDCS+NMES的作用效果可能与刺激部位、运动中不同部位肌肉做功大小有关。展开更多
基金This research is supported by Hunan Provincial Natural Science Foundation of China(Grant No.2021JJ30304)the General Topics of Hunan Social Science Achievement Evaluation Committee of China(Grant No.XSP22YBC366)the Key Scientific Research Project of Hunan Provincial Department of Education of China(Grant No.21B0592).
文摘Promoting the coupling coordination development of port and its hinterland city environments is an important way to improve urban economic competitiveness.Based on relevant data of 13 coastal port cities in eastern China from 2000 to 2018,this study explores the coupling coordination development of port and city environments and its impact on urban economic competitiveness by constructing the coupling coordination degree model and the panel threshold model.The research results show that:(1)In terms of the coupling coordination development of port and city environments,most coastal ports and their hinterland cities are in a state of moderate or serious disorder.Overall,the degree of coupling coordination of port and city environments needs to be further improved;(2)The coupling coordination degree of port and city environments has a significant impact on urban economic competitiveness,and this effect gradually increases with the development of the ports and the urban economy.Among the variables that impact the urban economic competitiveness,fixed assets investment and foreign trade are significant factors that can enhance urban economic competitiveness.(3)At present,there is a“U-shaped”relationship between the coupling coordination degree of port-city environments and the urban economic competitiveness.This relationship lies on the right side of the inflection point of the“U-shaped”curve.Therefore,following the concept of assigning priority to ecological development,expanding fixed assets investment and actively developing foreign trade can further enhance the urban economic competitiveness.
