China’s carbon neutrality: an extensive and profound systemic reform

● China has pledged ambitious carbon peak and neutrality goals for mitigating global climate change. ● Major challenges to achieve carbon neutrality in China are summarized. ● The new opportunities along the pathway of China’s carbon neutrality are discussed from four aspects. ● Five policy suggestions for China are provided. China is the largest developing economy and carbon dioxide emitter in the world, the carbon neutrality goal of which will have a profound influence on the mitigation pathway of global climate change. The transition towards a carbon-neutral society is integrated into the construction of ecological civilization in China, and brings profound implications for China’s socioeconomic development. Here, we not only summarize the major challenges in achieving carbon neutrality in China, but also identify the four potential new opportunities: namely, the acceleration of technology innovations, narrowing regional disparity by reshaping the value of resources, transforming the industrial structure, and co-benefits of pollution and carbon mitigation. Finally, we provide five policy suggestions and highlight the importance of balancing economic growth and carbon mitigation, and the joint efforts among the government, the enterprises, and the residents.     

Effects of Zr substitution on soot combustion over cubic fluorite-structured nanoceria: Soot-ceria contact and interfacial oxygen evolution

Ceria is widely used as a catalyst for soot combustion, but effects of Zr substitution on the reaction mechanism is ambiguous. The present work elucidates effects of Zr substitution on soot combustion over cubic fluorite-structured nanoceria. The nanostructured CeO₂, Ce_0.92Zr_0.08O₂, and Ce_0.84Zr_0.16O₂ composed of 5–6 nm crystallites display T_m-CO2 (the temperature at maximum CO₂ yield) at 383, 355, and 375°C under 10 vol.% O₂/N₂, respectively. The size of agglomerate decreases from 165.5 to 51.9–57.3 nm, which is beneficial for the soot-ceria contact. Moreover, Zr increases the amount of surface oxygen vacancies, generating more active oxygen (O₂^? and O^?) for soot oxidation. Thus, the activities of Ce_0.92Zr_0.08O₂ and Ce_0.84Zr_0.16O₂ in soot combustion are better than that of CeO₂. Although oxygen vacancies promote the migration of lattice O^2?, the enriched surface Zr also inhibits the mobility of lattice O^2?. Therefore, the T_m-CO2 of Ce_0.84Zr_0.16O₂ is higher than that of Ce_0.92Zr_0.08O₂. Based on reaction kinetic study, soot in direct contact with ceria preferentially decomposes with low activation energy, while the oxidation of isolated soot occurs through diffusion with high activation energy. The obtained findings provide new understanding on the soot combustion over nanoceria.     

对加快推进我国矿山生态修复的思考

绿色矿山建设是矿业领域践行"绿水青山就是金山银山"的重要体现。本文从矿山生态修复的内涵到外延，从问题识别到任务措施，从单一治理修复目标到生态系统功能修复目标，从矿山生态修复系统到与经济社会发展系统相结合等多个方面，系统地梳理矿山生态修复的解决路径，围绕矿业绿色发展提出一系列建议。     

关于“正弦振动试验”现行国家标准与正在修订中的新版标准的解读

正弦振动试验是试验室经常采用的振动方式,对应正弦振动试验国家标准GB／T2423．10应用非常广泛。本文介绍了该标准的用途、制修订背景等,在此基础上分析了现行正弦振动试验国家标准GB／T2423．10—2008与正在修订的6B／T2423．10—201×之间的异同之处,并指明了此标准应用中的几点注意的问题。     

蚀刻液水合肼还原除铜

将电路板厂废弃的蚀刻液,经氢氧化铜沉淀法回收大部分铜后,再采用水合肼还原,进一步除铜。反应温度为50℃,水合肼质量分数为3．0％,溶液pH为6．0,废液中铜的去除率可达98.5％,处理后废液中铜的质量浓度低于0．2g／L,可作为碱性蚀刻液重复利用。     

好氧颗粒污泥技术处理味精废水

采用好氧颗粒污泥技术处理味精废水.实验结果表明:前置缺氧段对反应器脱氮效果影响较小,脱氮过程主要是在好氧段实现;曝气段的最佳工艺条件为曝气量0.38 m3/h,曝气时间5.5 h;在进水COD、p(NH3-N)和TN分别为l000.00～1300.00,70.00～130.00,100.00～200.00 mg/L的条件下,COD、NH3-N和TN的去除率可分别维持在90％、99％和85％以上,实现了味精废水的高效脱氮处理.有机物主要在曝气初期的1.5 h内被去除,其在微生物体内以聚β-羟基丁酸形式储存,以提供反硝化过程中所需要的碳源.与普通SBR相比,接种好氧颗粒污泥后的反应器对味精废水具有更好的处理效果.     

特大城市集群绿色发展与生态足迹关联特征

本文以成渝城市群、长江中游城市群和长三角城市群为研究对象,解析不同空间尺度下绿色发展与生态足迹时空变化特征,并结合耦合协调度模型、环境库兹涅茨曲线（EKC）理论探究绿色发展与生态足迹的关联特征。研究表明,长江经济带城市群2000—2015年绿色发展水平逐年提升,约16.44%的城市达到较高水平,空间上呈现“东部高、西部低”的特征。人均三维生态足迹增长逐渐趋缓,成渝城市群达到峰值（5.21hm²）后逐年稳定下降。长江经济带绿色发展与生态足迹处于良好协调状态,绿色经济的快速发展带动了耦合协调度的提高。绿色发展与生态足迹存在倒“ U”形EKC曲线关系,由于自然资源基础和产业结构差异,成渝城市群（拐点出现在2008年）绿色发展与生态足迹协调关系好转早于中下游城市群（拐点分别在2019年、2012年）。四川、安徽应作为降低资源消耗的重点对象,未来应进一步加强区域中心城市的辐射带动作用,拉动周围城市提高绿色发展水平。研究成果能为区域绿色发展与生态环境协同管理提供思路与理论支持。     

厌氧工艺对含铬(Ⅵ)废水处理效果初探

以砂石和活性炭作为填料,自制厌氧生物滤床系统,并对系统进行驯化,发现完成驯化后的稳定系统具有良好的去铬(Ⅵ)能力.废水在系统中经过2 h运行,加入碳源的试验组与不加碳源的对照组的铬(Ⅵ)去除率分别为87.33%和66.31%.恒流泵最佳流量为47 mL/min,外加碳源后,铬(Ⅵ)的浓度由60 mg/L左右降到0.5 mg/L以下,需要4 h,而对照组需要14 h,铬(Ⅵ)浓度由64.66 mg/L提高到 75.53 mg/L时,对本系统负面影响甚微,提高到95.47 mg/L时,系统出水达标所需时间延长到7.5 h.本系统具有耐受一定程度的浓度冲击以及进一步驯化、提高处理负荷的潜力.     

自然灾害灾后重建技术及实践的研究进展

灾后重建是在灾害体发生之时及发生之后,采取应急救援、灾害管理,以及灾后评估、救助、规划等一系列过程,是一个典型的系统工程,可划分为前期应急重建、中期恢复重建及后期发展重建3部分。以自然灾害为主要研究对象,在分析中外关于灾后重建文献的基础之上,归纳了灾后重建的系统特征,介绍了灾后重建技术和实践的研究进展。灾后重建技术包括灾害分类分级、应急救援、灾后评估、灾害管理和重建规划5个方面,灾后重建实践研究分为地震、飓风、洪水和海啸4个方面,并对中外的灾后重建研究发展进行了展望。     

On the dissipation rate of temperature fluctuations in stably stratified flows

Environmental Fluid Mechanics - In this study, we explore several integral and outer length scales of turbulence which can be formulated by using the dissipation of temperature fluctuations (...