政府补助、外部融资抉择与企业创新绩效 ——基于中国上市制造企业面板数据的实证

为研究企业外部融资结构差异和政府补助对企业创新绩效的影响，运用固定效应模型，对2015-2018年中国实体上市制造企业面板数据进行了实证分析，结果发现：短期借款、长期借款与政府补助结合，未能对企业创新绩效产生显著的激励作用；企业发行债券会增强政府补助对创新绩效的激励效果；企业股权融资比例的提升会对创新绩效产生更显著的积极影响，相反政府补助的激励作用会受到削弱；当政府补助超过临界值后，对企业创新绩效由激励作用转变为抑制作用。未来政府补助应加强对小微企业的扶持，减少对企业融资行为的扭曲；企业应合理调整融资决策，促进政府补助和融资积极作用的有机结合，助力科技创新能力的提升。

Effects of Urban Green Infrastructure Spatial Pattern on PM 2.5 Based on MSPA

In consideration of the shortage of urban land, it is of great significance to optimize the spatial form of urban green infrastructure (UGI) to alleviate atmospheric particulate matter. However, the research on UGI spatial morphology and atmospheric particulate matter is mainly based on landscape pattern index analysis, rarely involving morphological spatial pattern analysis (MSPA). Based on MSPA and UGI connectivity analysis, the influence of MSPA elements and UGI connectivity on PM 2.5 concentration was studied in the 1000m×1000m areas surrounding 16 air quality monitoring points in Wuhan built-up area. The results showed that there are significant differences in MSPA elements among the 16 research units, which can be divided into two types: core and edge as the dominant elements, and the overall connectivity of UGI is higher in the former than in the latter. The higher the PM 2.5 concentration is, the more significant the correlation between UGI ratio, MSPA elements and PM 2.5 concentration is. As a whole, PM 2.5 concentration is negatively correlated with the area of core, perforation and the number of perforation and loop, and positively correlated with the area of islet and branches; and positive correlated with edge area in the case of slight pollution; the overall connectivity index EC (IIC) and the possible connectivity index EC (PC) were significantly negatively correlated with PM 2.5 concentration. Finally, the study proposed that increasing the core of UGI and reducing island area, strengthening the internal connectivity of UGI by loop and improving the connectivity of UGI are beneficial for improving PM 2.5 pollution.