China's high-speed rail (HSR) construction provides an ideal ‘quasi-natural experiment’ in which regional issues are investigated. This study explores how HSR affects innovation efficiency and explores the mediating effect of urban form. Based on panel data comprising 280 cities in China from 2006 to 2016, this study uses a time-varying difference-in-differences method to analyze whether HSR affects regional innovation, and it explores the mediating effect of urban form. The results show the following. (1) HSR significantly promotes regional innovation. The parallel trend test shows that the treatment group and the control group have the same trend before HSR construction. (2) Knowledge spillovers are important manifestations through which HSR promotes regional innovation. HSR can significantly improve the level of total factor productivity and human capital. (3) Urban form mediates the impact of HSR on regional innovation significantly, which varies across the different indexes of different urban forms.

This study examines the impact of innovative city pilot policies (ICPP) on urban total factor productivity (TFP) and explores the mediating role of absorptive capacity in the context of innovative cities pilot policies in China. Based on panel data of 281 cities in China during 2006-2018, we introduce a difference-in-differences approach to analyse whether ICPP have a facilitating effect on urban TFP. The results of the study are as follows. (1) ICPP significantly contribute to urban TFP. (2) The mediating effect shows that the construction of innovative cities can enhance the absorptive capacity of cities and then improve TFP. (3) There is significant heterogeneity in the construction of innovative cities with different urban forms.

Based on the panel data of 283 cities in China from 2009 to 2018, this paper analyzes the effect of urban green scientific and technological innovation enhancement on hazardous air pollutants using the GS2SLS method, which simultaneously controls for model endogeneity and spatial spillover effects and reveals the transmission mechanism of urban green scientific and technological innovation level. It was found that (1) There is a significant spatial spillover effect of hazardous air pollutants between regions, both in China as a whole and in the eastern, central, and western parts of the country, and the spatial spillover effect of hazardous air pollutants is significantly greater in the eastern and central parts of China than in the western parts. (2) Green technological innovation has a significant inhibitory effect on hazardous air pollutants in cities in eastern and central China. An extended study found that the improvement in green technology levels in innovative cities has a better effect on controlling hazardous air pollutants than in non-innovative cities. (3) The energy- saving and green economy effects have a mediating influence on the effect of green technological innovation on hazardous air pollutants in cities, and the simultaneous occurrence of these two effects in green technological innovation serves to enhance the transmission of hazardous air pollutants in order to facilitate the long-term management of haze.

Environmental regulation and innovative development are essential means to solve the negative externalities of environmental pollution. However, developing countries often face the dual pressures of environmental pollution and innovative development. This paper focuses on whether environmental protection policies (EPP) can achieve a win-win situation between green development and innovative development. Based on the panel data of 277 cities in China from 2006 to 2016, this paper studies the impact of China's EPP on urban innovation efficiency by using a time-varying difference-in-differences approach. Combined with the geographical features of Chinese cities, we further take urban form into the mediating effect analysis. The results show that (1) EPP has a significant positive impact on innovation efficiency, and the result satisfies the parallel trend test; (2) the robustness test shows that EPP has technological innovation and diffusion effects; and (3) the mediating effect test show that urban form has a significant mediating effect on the impact of EPP on innovation efficiency. Therefore, environmental policies should be formulated considering the differences of urban form to achieve the optimal implementation effect.

With the increase in economic globalization, developing countries are gradually embedding in global value chains (GVCs). Further, the air pollution in these countries has become increasingly severe, threatening the health of residents. Based on this background, this study tests whether GVC embedment affects air pollution using panel data on 239 cities in China from 2004 to 2013. The results show that GVC embedment aggravates air pollution in Chinese cities. Further, a heterogeneity analysis shows that the positive relationship between GVC embedment and air pollution is stronger in cities in coastal and eastern provinces. We find two different channels for how GVC embedment affects air pollution. First, GVC embedment aggravates air pollution through scale effects, which is mainly reflected in the expansion of total exports and the value-added scale. Second, the embedment of GVCs reduces air pollution through technology effects, which is reflected primarily in manufacturing and service agglomeration.

基于手工查找的2000—2006年全国336个地级市最低工资标准数据、中国进出口关税数据、工业企业数据和海关进出口贸易数据,分别从国家和省际(以湖北省为代表)两个维度,以贸易自由化为研究背景考察了最低工资对企业行为和绩效的影响.研究结果表明,贸易自由化对中国和湖北省企业出口国内附加值率均有正向影响.在进行一系列稳健性检验后,结论依旧稳健.关于最低工资的影响效应,发现对全国样本而言,随着地区最低工资标准不断提高,贸易自由化对企业出口国内附加值率的提升作用越大,而在湖北省层面,最低工资标准并不能显著增强(或削弱)贸易自由化对湖北省企业出口国内附加值率的提升作用.

本文以2015年研发费用加计扣除政策变化作为一次“准自然实验”,基于2013-2017年上市公司的研发投入数据,采用双重差分法(DID)考察了研发费用加计扣除政策对企业研发投入的影响,结果显示研发费用加计扣除政策对企业研发投入存在显著的促进作用.在稳健性检验中,本文将因变量改为研发投入占营业收入的比值与研发人员数量的对数进行回归,结果表明研发费用加计扣除政策同样产生了正向促进作用.在企业异质性分析中,本文分别就不同地区、不同所有制及不同名义税率与实际税负的企业进行了回归,结果显示针对不同类型的企业,研发费用加计扣除政策的作用效果会产生差异.本文建议注重政策适用的靶向性,加大对中小型企业的税收优惠力度,同时协调不同税收优惠政策,进一步开放政策适用范围.

通过深度挖掘1995—2014年CEPII-BACI数据库中中国与"一带一路"沿线国的农产品贸易数据,综合运用引力模型等前沿实证分析方法,刻画分析了人民币汇率波动对中国农产品出口贸易的影响及渠道机制,以期有效推进"一带一路"倡议中中国与沿线国之间农产品贸易的开展.结果表明:人民币汇率波动幅度的增加将显著降低农产品出口贸易额.随后的稳健性检验中将滞后一期的汇率波动纳入实证分析,仍旧发现汇率波动与农产品出口的负相关关系.随后将CPI作为中间变量对汇率传导机制进行了实证分析,发现CPI的降低将使得该国的农产品进口量减少.

本文利用CEPII-BACI数据库中2000-2015年中国与175个国家和地区的双边贸易数据,通过构建扩展的引力模型,刻画分析了经济政策不确定性波动对中国出口技术复杂度的影响及渠道机制,以期促进中国出口贸易的转型升级.结果 表明:经济政策不确定性波动的增加会显著抑制中国的出口技术复杂度,而在内生性检验和稳健性检验中,回归结果仍然保持一致.随后的影响机制分析中,本文发现经济政策不确定性波动会通过抑制制度质量导致出口技术复杂度降低.