基于地理探测器的京津冀地区制造业集聚对PM_(2.5)浓度的影响研究

[目的/意义]探究京津冀地区雾霾污染的分布特征以及影响因素,厘清PM_(2.5)浓度与制造业集聚之间的关系,可能是推动京津冀地区绿色发展的重要途径。[方法/过程]本文基于2005—2013年京津冀地区规模以上工业企业微观数据以及NASA的年均PM_(2.5)浓度数据,以京津冀204个区(县)为研究对象,探究制造业集聚与PM_(2.5)浓度的时空演化特征,运用地理探测器方法,从集聚形式和行业异质性两个视角揭示PM_(2.5)浓度空间分布的影响机理。[结果/结论]①京津冀地区年均PM_(2.5)浓度呈现西北低、东南高的空间分布格局,且上升态势明显。制造业集聚形式呈现空间分异特征,其中集聚密度呈现“京-津-邯”三核心组团式发展格局。专业化集聚表现为“张-保-邢-秦”四小型核心发展格局。多样性集聚呈现集中连片式发展格局。②不同时期的制造业集聚形式对PM_(2.5)浓度的解释力存在差异。集聚密度始终是PM_(2.5)浓度空间分布的主导因素,但影响程度有所下降,专业化集聚对于PM_(2.5)浓度的解释力有所增强。不同集聚形式的交互作用加强了对PM_(2.5)浓度空间分布的影响程度。③从行业异质性来看,化学原料及化学制品制造业是导致PM_(2.5)浓度空间分异的主导因素,化学原料及化学制品制造业与其他因子的交互作用的解释力明显强于其他因子间的交互作用,其与黑色金属冶炼及压延加工业交互作用的解释力最高。因此,引导制造业空间合理集聚、有序集聚、多样性集聚,加大偏污染型、重化工产业的疏解力度,加快推动制造业绿色环保转型,是京津冀地区PM_(2.5)环境治理的重要战略选择。

Optical Design of a Solar Parabolic Concentrating Collector Based on Trapezoidal Reflective Petals

In this paper, detailed optical of the solar parabolic dish concentrator is presented. The system has diameter D = 2,800 mm and focal length f = 1,400 mm. The efficient conversion of solar radiation in heat at these temperature levels requires a use of concentrating solar collectors. In this paper, detailed optical design of the solar parabolic dish concentrator is presented. The parabolic dish of the solar system consists from 12 curvilinear trapezoidal reflective petals. This paper presents optical simulations of the parabolic solar concentrator unit using the ray-tracing software TracePro. The total flux on receiver and the distribution of irradiance for absorbed flux on center and periphery receiver are given. The total flux at the focal region is 4,031.3 W. The goal of this paper is to present optical design of a low-tech solar concentrator, that can be used as a potentially low-cost tool for laboratory-scale research on the medium-temperature thermal processes, cooling, industrial processes, solar cooking and polygeneration systems, etc.