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提升“一带一路”区域商贸便捷度对中国出口贸易的影响 被引量:1
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作者 房林 《中国市场》 2021年第31期1-4,11,共5页
文章选取了"一带一路"区域内具有代表性的28个经济体作为样本进行分析,以Wilson,Mann和Otsuki(2003)构建的指标体系为基础,保留原引力分析模型的经济体总量参数值和经济体间的地理空间距离的参数值,对衍生标志值进行调整,加... 文章选取了"一带一路"区域内具有代表性的28个经济体作为样本进行分析,以Wilson,Mann和Otsuki(2003)构建的指标体系为基础,保留原引力分析模型的经济体总量参数值和经济体间的地理空间距离的参数值,对衍生标志值进行调整,加入商贸便捷度参数值、关税税率参数值及人口参数值这三个中介变量值,来分析研究"一带一路"区域商贸便捷度提升对中国出口贸易的"整体效应"。出于商贸便捷度构成因素的研究需要,展开商贸便捷程度标志值,将项下二级标志值,即公共基础设施、制度环境、通关环境和金融电子化直接替代原先商贸便捷度标志值,构建"一带一路"区域便捷度提升对中国出口贸易的"分项效应"分析模型。回归分析发现,该四项标志值的符号为正,即这四项参数内容都对中国出口贸易带来正面的影响。 展开更多
关键词 “一带一路” 商贸便捷度 引力分析模型
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Empirical Analysis of City Contact in Zhujiang(Pearl) River Delta, China 被引量:7
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作者 TONG De LIU Tao +1 位作者 LI Guicai YU Lei 《Chinese Geographical Science》 SCIE CSCD 2014年第3期384-392,共9页
In traditional urban geography, city contact research is a classic study element in city research. In general, researchers use the traditional gravity model to characterize the contacts that exist between two cities. ... In traditional urban geography, city contact research is a classic study element in city research. In general, researchers use the traditional gravity model to characterize the contacts that exist between two cities. The traditional gravity model assumes ideal conditions, but these preconditions and their results often do not exist in realistic conditions. Thus, we used a modified gravity model to characterize the city contacts within a specific region. This model considers factors such as intercity complementarities, government intervention, and the diversity of the transportation infrastructure which is characterized as the transportation distance instead of the traditional Euclidean distance. We applied this model to an empirical study of city contact in the Zhujiang(Pearl) River Delta(PRD) of China. The regression results indicated that the modified gravity model could measure city contact more accurately and comprehensively than the traditional gravity model, i.e., it yielded a higher adjusted R2 value(0.379) than the traditional gravity model result(0.259). Our study also suggests that, in addition to urban-regional and metropolitan development, the complementarities of the basic functions of cities at the administrative and market levels, as well as the corporeal and immaterial levels, play very significant roles in the characterization of city contact. Given the complexity of city contact, it will be necessary to consider more relevant influential factors in the modified gravity model to characterize the features of city contact in the future. 展开更多
关键词 city contact function complementarities government intervention gravity model Zhujiang (Pearl) River Delta (PRD) China
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Spatiotemporal spectrum and momentum flux of the stratospheric gravity waves generated by a typhoon 被引量:17
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作者 CHEN Dan CHEN ZeYu Lü DaRen 《Science China Earth Sciences》 SCIE EI CAS 2013年第1期54-62,共9页
The simulation results of Typhoon Matsa (2005) by using the Weather Research and Forecasting (WRF) model show that pro- nounced stratospheric gravity waves (GWs) are generated in the vicinity of the typhoon. Usi... The simulation results of Typhoon Matsa (2005) by using the Weather Research and Forecasting (WRF) model show that pro- nounced stratospheric gravity waves (GWs) are generated in the vicinity of the typhoon. Using the model output, we investi- gate the spatial structures and the temporal variations of the GWs through a three dimensional (3-d) spectral analysis, i.e. the spectrum with respect to two horizontal wavenumbers and frequency. We further derive the momentum flux carried by the GWs. Spectral investigation results show that the power spectral density (PSD) of the GWs exhibits a single-peaked spectrum, which consists primarily of a distinct spectrum at horizontal wavelength of -1000 km, time period of 12-18 h, and vertical wavelength of 7-9 kin. This spectrum is different from the spectra of GWs generated by deep convections disclosed by the previous researches. Both the PSD and momentum flux spectrum are prominent in positive kh portion, which is consistent with the fact that the GWs propagate in the upstream of mean flow. Large momentum flux is found to be associated with the GWs, and the net zonal momentum flux is 0.7845×10-3 Pa at 20 km height, which can account for -26% of the momentum flux that is required in driving the QBO phenomenon. 展开更多
关键词 stratospheric gravity waves TYPHOON 3-d spectrum PSD momentum flux
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