Environmental decentralization,environmental public service,and public health: evidence from 289 cities in China

Environmental Geochemistry and Health - Effective supply of environmental public services (EPS) is important to guarantee the mitigation of residential pollution exposure risk. This study analyzes...     

风险感知、农业社会化服务与稻农生物农药技术采纳行为

在农业社会化服务体系不断完善的背景下,利用鄂、赣两省704户稻农的调查数据,采用二元Logit模型实证分析了风险感知和农业社会化服务对稻农生物农药技术采纳行为的影响.结果表明:(1)农户对生物农药技术的采用率较低,仍有55.54％的稻农未采用生物农药;(2)风险感知对稻农生物农药技术采纳行为存在显著影响,技术风险感知和市场风险感知越强的稻农,采用生物农药技术的可能性越小;(3)农业社会化服务对稻农生物农药技术采纳行为具有显著的正向作用,且能有效缓解风险感知对稻农生物农药技术采纳行为的抑制作用;(4)相较于规模户,农业社会化服务更能有效缓解市场风险感知对小农户采用生物农药技术的抑制作用,但对其技术风险感知的缓解作用则不明显.因此,在加大技术宣传和田间地头指导,完善农资市场和农产品市场体系,增加生物农药补贴力度以降低农户技术与市场风险感知的同时,有必要通过拓展农业社会化服务的服务内容和服务对象,优化小农户的农产品市场环境,以此促进生物农药技术的推广和应用.     

Conversion of waste plastics into value-added carbon materials

Plastic pollution is a major environmental issue worldwide, calling for advanced methods to recycle waste plastics in the context of the circular economy. Here we review methods and strategies to convert waste plastics into value-added carbon materials, with focus on sources, properties, pretreatment of waste plastics, and on preparation of carbon materials. Pretreatment techniques include mechanical crushing, plastic stabilization and electrospinning. Carbon materials such as carbon nanotubes, graphene, carbon nanosheets, carbon spheres and porous carbon are prepared by oxygen-limited carbonization, catalytic carbonization, the template-based method, and pressure carbonization. We emphasize the conversion of polyethene terephthalate, polyethylene, polypropylene, polystyrene, halogenated plastics, polyurethane and mixed plastics.

     

Mitochondrial toxicity and in vitro biological effects of ambient PM2.5 from an urban site in China

Abstract

The roles of PM_2.5-induced mitochondrial damage and oxidative stress on mast cell degranulation were examined in vitro. Mast cells were treated with suspensions of PM_2.5 in Dulbecco’s modified Eagle’s medium at concentrations from 25 to 200?mg/L in the absence or presence of 10?mmol/L N-acetyl-L-cysteine. Biological effects and mitochondrial function were assessed by determining cell viability, β-hexosaminidase release, interleukin-4 secretion, reactive oxygen species generation, adenosine triphosphate production, potential alteration of mitochondrial membrane, and activities of mitochondrial electron transport chain complexes I and III. Exposure of mast cells to PM_2.5 induced reduction of adenosine triphosphate production, collapse of mitochondrial membrane potential, and inhibition of the activity of complex III. Co-treatment of mast cells exposed to PM_2.5 with N-acetyl-L-cysteine attenuated cytotoxicity and the production of reactive oxygen species, and decreased the release of β-hexosaminidase and interleukin-4. Evidently, PM_2.5-induced oxidative stress plays an essential role in mitochondrial toxicity and mast cell activation.     

“三线一单”促进四川省高质量发展

过去40年来我国经济建设取得了举世瞩目的成绩,但是也留下了很多生态环境问题。目前我国经济已经由高速增长阶段转向高质量发展阶段,但高质量发展缺乏指标体系和具体路径。“三线一单”是一套生态环境分区管控体系,其主要目的是统筹地方社会经济与环境保护的矛盾,促进经济结构转型。四川省在“三线一单”编制过程中,通过建立指标体系从生态环境保护的角度为地区高质量发展提供了量化标准,通过差异化管控要求为地区高质量发展提供了具体路径,从生态环境角度助力高质量发展。     

基于仿真实验的导轨结合面刚度建模方法研究

以分形理论和分形理论与域扩展因子为基础,设计了四种导轨动态接触刚度的理论计算模型,并将结果分别应用于仿真分析中,获得了四种不同方案下的有限元仿真分析结果;设计搭建了一种仅含导轨结合面的实验平台,并进行了模态试验;通过各方案仿真分析结果与实验的比较,获得了导轨结合面刚度建模方法的最优方案。     

光伏组件可调节式夹具设计及试验研究

机械载荷试验作为考查光伏组件可靠性的重要手段之一,新版IEC标准中对于该项测试的要求也变得更加细致。本文介绍了一种光伏组件机械载荷测试的可调节式安装夹具设计,并根据标准IEC 61215-2:2016中静态机械载荷试验的要求,利用该夹具测试了两块不同版型的光伏组件。本设计夹具表现出良好的普适性与测试可靠性,测试结果表明破损程度直接导致光伏组件发电性能的降低,而其内在原因可能在于内部电阻的变化。     

基于STIRPAT和GM(1,1)模型的湖南省农地投入碳排放增长机理及趋势预测

探索农地投入的碳排放特征、增长机理及趋势预测,并提出减排对策对农业发展向低碳绿色转型具有重要意义。研究采用回归分析法、STIRPAT和GM(1,1)模型解析湖南省农地投入碳排放增长机理并做出趋势预测。结果表明:2000~2014年湖南省农地投入碳排放量呈上升趋势,年均增长率为3.25%,各类碳源中化肥累计的碳排放量最大,其次是农药;此外翻耕、农药、农膜、柴油、灌溉、化肥累计碳排放年均增长量分别为0.68%、3.22%、7.47%、6.42%、2.57%、3.25%。农业人口、人均农业GDP、机械化水平、农业生产效率、农业产业结构显著影响农地碳排放,各因素每发生1%的变动会相应带来农地碳排放量约0.20%、0.95%、0.12%、0.98%和0.93%的变化。通过GM(1,1)模型对2016~2020年湖南省农地投入碳排放量进行预测,碳排放量呈持续上升趋势,2020年预计达到430.43万t。最后根据研究结果提出促进农地投入碳减排的政策建议。