城乡融合对中国农业碳排放效率的影响及其机制   总被引：1，自引：0，他引：1  

谢会强  吴晓迪 《资源科学》2023,45(1):48-61

【目的】城乡融合作为农业生产要素配置效率提升的重要手段,是影响农业碳排放效率的关键因素。【方法】本文采用中国2005—2020年省域面板数据,在测度城乡融合发展水平和农业碳排放效率的基础上,综合运用固定效应模型、空间自回归模型和门槛效应模型探究了城乡融合发展对农业碳排放效率的影响效果及其作用机制。【结果】研究发现：①总体上,城乡融合发展指数对农业碳排放效率具有显著的负向影响。机制检验表明,城乡融合发展有助于提升农业低碳技术效率,但对前沿技术进步具有显著负向影响,进而不利于改善农业碳排放效率。上述研究结论在空间溢出视角下仍然成立。②从城乡融合发展的不同维度来看,“人的融合”能够通过改善技术效率来有效提升农业碳排放效率,而“地的融合”和“资本的融合”虽然对技术效率均具有正向影响,但由于受到技术进步的负向制约,最终阻碍了农业碳排放效率的总体提升。③门槛计量分析发现,地区经济发展水平是约束城乡融合发展和农业碳排放效率关系的显著门槛变量,当地区经济发展水平迈过阈值后,城乡融合发展能够对农业碳排放效率产生显著的提升效应。【结论】因此,地方政府在推进城乡融合发展过程中,应兼顾地区经济发展水平,着力构建以“人”为核心,统筹“地”和“资本”融合的城乡融合体系与机制,为以推动城乡协调发展为契机来实现低碳农业高质量发展创造条件。  相似文献   

技术效率、环境分权与减碳降霾     

潘雄锋  袁赛  冯圣涵 《研究与发展管理》2023,35(4):50-64

技术效率对减碳降霾的影响是否存在环境分权的门槛效应？基于这一现实问题,采用随机前沿模型测算2006—2018年中国省域技术效率,分析其对减碳降霾的“水平效应”,并运用动态门槛模型检验其对减碳降霾的异质性环境分权门槛效应,借此研究异质性环境分权的最优配置方式。结果表明：技术效率对减碳降霾具有积极的“水平效应”。改善技术效率可减少资源投入冗余,改善资源配置效率,从而实现减碳降霾;技术效率对减碳降霾的影响存在异质性环境分权门槛效应。随着环境分权水平提高,技术效率对碳排放和雾霾污染的影响分别呈“W”形和倒“N”形;初步估计环境分权范围于（0.806, 1.065）,可实现技术效率对减碳降霾的积极作用。同时,中央政府在环境行政、监察方面需适当下放权力,而地方政府需上移环境监测权力。  相似文献   

Discovery of carbon-based strongest and hardest amorphous material     

Shuangshuang Zhang  Zihe Li  Kun Luo  Julong He  Yufei Gao  Alexander V Soldatov  Vicente Benavides  Kaiyuan Shi  Anmin Nie  Bin Zhang  Wentao Hu  Mengdong Ma  Yong Liu  Bin Wen  Guoying Gao  Bing Liu  Yang Zhang  Yu Shu  Dongli Yu  Xiang-Feng Zhou  Zhisheng Zhao  Bo Xu  Lei Su  Guoqiang Yang  Olga P Chernogorova  Yongjun Tian 《国家科学评论(英文版)》2022,9(1)

Carbon is one of the most fascinating elements due to its structurally diverse allotropic forms stemming from its bonding varieties (sp, sp² and sp³). Exploring new forms of carbon has been the eternal theme of scientific research. Herein, we report on amorphous (AM) carbon materials with a high fraction of sp³ bonding recovered from compression of fullerene C₆₀ under high pressure and high temperature, previously unexplored. Analysis of photoluminescence and absorption spectra demonstrates that they are semiconducting with a bandgap range of 1.5–2.2 eV, comparable to that of widely used AM silicon. Comprehensive mechanical tests demonstrate that synthesized AM-III carbon is the hardest and strongest AM material known to date, and can scratch diamond crystal and approach its strength. The produced AM carbon materials combine outstanding mechanical and electronic properties, and may potentially be used in photovoltaic applications that require ultrahigh strength and wear resistance.  相似文献   

考虑碳排放的易腐品供应链选址-路径-库存联合优化     

王梦梦  韩晓龙 《上海海事大学学报》2019,40(4):45-51

为优化易腐品供应链运作,降低总成本和碳排放,建立易腐品损坏函数,将多配送中心选址、车辆路径和库存管理策略相结合,提出考虑客户随机需求的易腐品供应链选址-路径-库存联合优化模型。设计两阶段启发式算法求解这个大规模问题。对单位碳排放价格变动和服从正态分布的客户随机需求波动进行灵敏度分析。对模型和算法进行算例分析,并与相关文献对比,结果表明,模型和算法具有良好的适用性。  相似文献   

Media development and process parameter optimization using statistical experimental designs for the production of nonribosomal peptides in Escherichia coli     

《Electronic Journal of Biotechnology》2021

BackgroundNonribosomal peptide synthases (NRPS) can synthesize functionally diverse bioactive peptides by incorporating nonproteinogenic amino acids, offering a rich source of new drug leads. The bacterium Escherichia coli is a well-characterized production host and a promising candidate for the synthesis of nonribosomal peptides, but only limited bioprocess engineering has been reported for such molecules. We therefore developed a medium and optimized process parameters using the design of experiments (DoE) approach.ResultsWe found that glycerol is not suitable as a carbon source for rhabdopeptide production, at least for the NRPS used for this study. Alternative carbon sources from the tricarboxylic acid cycle achieved much higher yields. DoE was used to optimize the pH and temperature in a stirred-tank reactor, revealing that optimal growth and optimal production required substantially different conditions.ConclusionsWe developed a chemically defined adapted M9 medium matching the performance of complex medium (lysogeny broth) in terms of product concentration. The maximum yield in the reactor under optimized conditions was 126 mg L^-1, representing a 31-fold increase compared to the first shaking-flask experiments with M9 medium and glycerol as the carbon source. Conditions that promoted cell growth tended to inhibit NRPS productivity. The challenge was therefore to find a compromise between these factors as the basis for further process development.How to cite: Oestreich AM, Suli LI, Gerlach D. et al. Media development and process parameter optimization using statistical experimental designs for the production of nonribosomal peptides in Escherichia coli. Electron J Biotechnol 2021;52. https://doi.org/10.1016/j.ejbt.2021.05.001  相似文献   

低碳城市试点对企业绿色技术创新的影响     

熊广勤石大千  李美娜 《科研管理》2021,41(12):93-102

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Adsorption characteristics of activated carbon derived from scrap tires for malachite green: Influence of small organics     

李丽  刘玉静  王佳平  刘双喜  朱坦 《天津大学学报(英文版)》2013,19(6):425-429

The influence of small organics on the adsorption characteristics of activated carbon produced from industrial pyrolytic tire char（APTC）for malachite green（MG） was investigated by a batch method. Phenol was chosen as the representative of small organics. The effects of phenol on adsorption equilibrium, kinetics and thermodynamics were studied systematically. The results indicate that APTC is a potential adsorbent for MG. The presence of phenol decreases the adsorption capacity of APTC for MG, but improves the rate of adsorption, while the adsorption characteristics, such as equilibrium, kinetics and thermodynamics are not affected by phenol. The adsorption equilibrium data follow Langmuir isotherm and the kinetic data are well described by the pseudo-second-order kinetic model. The adsorption process follows intra-particle diffusion model and the adsorption rate is determined by more than one process. Thermodynamic study shows that the adsorption is an endothermic and spontaneous physisorption process.  相似文献   

基于谈判的碳排放权拍卖机制设计     

王晔  刘俊伶 《通化师范学院学报》2013,(10):142-144,F0003

随着低碳经济的蓬勃发展,相应地衍生出诸多与碳排放相关的金融需求,而其中的碳排放权就是最重要的低碳金融商品之一.该文主要从碳排放权拍卖者角度出发,设计一种基于谈判的拍卖机制,使得拍卖者的收益达到最大化,同时资源也达到了最有效的配置.另外,文中除了计算拍卖者的期望收益外,也考虑了谈判的采购商和竞标者的期望收益.  相似文献   

低碳经济的哲学思考     

杨小军  林敏 《黄河科技大学学报》2013,15(3):46-49

低碳经济的提出不仅源于传统经济发展模式弊端的直接认识,而且更重要的是源于对导致这些弊端线性还原论思维范式及其实践方式的反思。低碳经济以寻求解决全球气候变化为突破口,追求人与自然关系的和谐发展,倡导公平的发展理念,以实现人的全面发展为根本目标,从而超越了传统高碳经济发展模式的线性特征,以非线性思维为思维基础的低碳经济是人类发展思维范式变革的必然结果。  相似文献   

阿魏酸在多壁碳纳米管修饰玻碳电极上的电化学行为及其测定     

郭英  高云涛 《郧阳师范高等专科学校学报》2013,33(3):7-10

制备多壁碳纳米管(MWNT)修饰玻碳电极,研究阿魏酸在该电极上的电化学行为及其测定方法,本法是一种可靠、快捷、灵敏的检测方法,可以用于阿魏酸含量的测定.  相似文献