29 results on '"Zheng, Yuhan"'
Search Results
2. Metagenomics reveals the influence of small microplastics on microbial communities in coastal sediments
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Zheng, Yuhan, Su, Zhiguo, Liu, Dantong, Huang, Bei, Mu, Qinglin, Li, Yunong, and Wen, Donghui
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- 2024
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3. State of the art overview wearable biohazard gas sensors based on nanosheets for environment monitoring applications
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Liu, Chen, Wang, Qianqian, Wang, Chunge, Wang, Qingfeng, Zhao, Wenjie, He, Zhaotao, Zheng, Yuhan, Jing, Ying, Sun, Xu, and Zhang, Sheng
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- 2023
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4. Reductive dehalogenation pathways and inhibition mechanisms of 2,5-dichloronitrobenzene in UV/sulfite advanced reduction process
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Ren, Hang, Xu, Ranyun, Chi, Tongtong, Li, Feifei, Zheng, Yuhan, Tian, Jinping, and Chen, Lyujun
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- 2023
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5. Copper(II) based low molecular weight collagen fragments-chlorin e6 nanoparticles synergize anti-cancer and anti-bacteria photodynamic therapy
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Zhang, Ning, Zheng, Yuhan, Wang, Zelin, and Liu, Xiaoyu
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- 2022
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6. Enhancing infrastructural dynamic responses to critical residents' needs for urban resilience through machine learning and hypernetwork analysis.
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Zhao, Zeyu, Zhou, Xiaoshan, Zheng, Yuhan, Meng, Tianguang, and Fang, Dongping
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MACHINE learning ,EXTREME weather ,DISASTER resilience ,CITY dwellers ,EMERGENCY management ,INFRASTRUCTURE (Economics) - Abstract
• Categorized post-disaster residents' needs using empirical data-driven approaches. • Modeled the dynamic interplay between residents' needs and infrastructure recovery. • Introduced a metric for assessing urban resilience through needs satisfaction. • Explored residents' needs evolution post-disaster with hyperedge network analysis. The increasing frequency of extreme weather events poses ever greater challenges to urban resilience and residents' quality of life. Despite a growing trend advocating for an anthropocentric approach to urban resilience, there remains an inadequate understanding of the evolving hierarchical needs of residents during post-disaster periods, especially considering the interplay with infrastructure service restoration. This study aims to address the gap by elucidating how emergency governance and urban infrastructure repairs can effectively address critical residents' needs, providing empirical insights for improved resource allocation in infrastructure rush-repair scenarios. First, we categorize residents' needs into three layers (safety and health, social livelihood and civic engagement) using Latent Dirichlet Allocation topic modeling. Subsequently, we present an urban resilience assessment framework that traces the recovery of residents' needs alongside dynamic infrastructural functionality restoration, benchmarking against pre-disaster levels. Additionally, hypernetwork analyses are adopted to identify critical and evolving patterns of residents' post-disaster needs over time. The robustness of our proposed framework is validated through its application to a dataset comprising 220,567 records from residents' appeals during three recurrent rainfall events in Beijing. Theoretically, this study models the dynamic interactions between residents' needs and infrastructure response during urban post-disaster recovery. Practically, the pinpointed critical needs guide efficient infrastructure rush-repairs and proactive disaster prevention in infrastructure maintenance. [ABSTRACT FROM AUTHOR]
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- 2024
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7. The impact of land consolidation on rural vitalization at village level: A case study of a Chinese village.
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Jiang, Yanfeng, Long, Hualou, Tang, Yu-ting, Deng, Wu, Chen, Kunqiu, and Zheng, Yuhan
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LAND consolidation ,TOMATO growers ,MOBILE geographic information systems ,CHINA studies ,RURAL development ,ECOLOGICAL modernization ,INDUSTRIAL districts - Abstract
Rural land consolidation (RLC) is beneficial to rural development to a certain extent. While acknowledging this relationship, little is known about the extent of the impact of RLC on rural vitalization at the village level and its change. Based on the theoretical analytical framework and multi-source data, this study adopts field investigation and GIS technology in Jinzhuang Village, China, to qualitatively reveal how RLC affects rural development and quantitatively analyze the effectiveness of RLC on local vitalization. The results show that greenhouse-led RLC promotes the spatial restructuring and industrial transformation of Jinzhuang Village. In this process, the restructuring of production-living-ecological space is mutually reinforced and restrictive, and compared with the decrease of the ecological space, the production space has gradually expanded and the living space has increased slightly. On the whole, RLC has boosted the development level of Jinzhuang Village. However, its main contribution lies in the socio-economic aspects, at the expense of the ecological environment, and its positive and negative effects, based on the quantitative analysis, on cultural development almost cancel each other out. Additionally, working in greenhouses for years poses a health risk to tomato farmers. Based on the above analysis and discussion, policy recommendations are provided. • An analysis framework concerning the impact of RLC on rural vitalization at the village level is established. • RLC promotes local spatial restructuring and industrial transformation. • We found the greenhouse-led RLC promotes socio-economic development rather than eco-environmental and cultural development. • Simple RLC led by economic benefits should be transformed into comprehensive RLC with coordination between multi-functions. [ABSTRACT FROM AUTHOR]
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- 2021
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8. Research on complexation ability, aromaticity, mobility and cytotoxicity of humic-like substances during degradation process by electrochemical oxidation.
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Deng, Yang, Chen, Nan, Feng, Chuanping, Chen, Fangxin, Wang, Haishuang, Feng, Zhengyuan, Zheng, Yuhan, Kuang, Peijing, and Hu, Weiwu
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AROMATICITY ,TOXICITY testing ,SEWAGE ,DISSOLVED organic matter ,OXIDATION ,FUNCTIONAL groups ,HYDROGEN bonding - Abstract
The humic-like substances were the main organic components in most wastewater (e.g. domestic sewage, toilet wastewater and landfill leachate). Two types of actual humic-like substances (fulvic acid (FA) and biologically treated landfill leachate (BTLL)) were selected to describe the changes in the properties of humic-like substances (complexation ability, aromaticity and mobility) during electrochemical oxidation. Meanwhile, the acute cytotoxicity of FA and BTLL was also tested by acute toxicological test of luminescent bacteria. The results showed that the consumption of coordinating groups such as phenolic groups and hydrogen bonds reduced the complexation ability of FA and BTLL. The functional groups were degraded with the removal order of quinone group, phenolic group and aromatic group, and finally realized the molecular saturation and aromaticity decrease for humic-like substances. The mobility of FA and BTLL was decreased because of the enhancement of hydrophobicity during electrolysis process. Furthermore, the available chlorine produced during electrochemical oxidation was the main acute cytotoxicity substance, therefore, it is necessary to remove it before discharge in order to reduce ecological risks. This study provides a basis for understanding and evaluating the electrochemical degradation process of humic-like substances in detail. The changes of complexation ability, aromaticity, mobility and cytotoxicity of humic-like substances during electrochemical oxidation process. Image 1 • Complexation, aromaticity and mobility of humic-like were decreased by electrolysis. • Functional groups were degraded with the order of quinone, phenolic and aromatic. • The hydrophobicity of humic-like substances was enhanced during electrolysis. • The effluent acute cytotoxicity was decreased with the available chlorine removal. • Electrochemical oxidation was an approaching technology with low ecological risk. [ABSTRACT FROM AUTHOR]
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- 2019
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9. Assessing mangrove conservation in China by integrating mangrove ecosystem into ecological footprint accounting.
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Zheng, Yuhan, Takeuchi, Wataru, and Jiang, Qutu
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MANGROVE plants ,MANGROVE ecology ,ECOLOGICAL impact ,CARBON sequestration in forests ,ECOSYSTEM management ,MANGROVE forests ,ECOSYSTEM health ,CARBON sequestration - Abstract
Mangrove conservation effort have been undertaken in China, but there is still a lack of quantitative assessment of its eco-environmental benefits. The ecological footprint (EF) is an important indicator of the sustainability of ecosystems, with carbon footprint (CF) and biocapacity (BC) being key indicators of forest ecosystems. Despite the high carbon sequestration capacity of mangrove ecosystems, they have not yet been included in EF. This study introduces mangrove ecosystems into EF accounting and assesses the eco-environmental benefits of mangrove conservation in China. To achieve this, the net ecosystem exchange (NEE) of mangrove forests was estimated based on the gross primary production and respiration rates. Average forest carbon sequestration (AFCS) and yield factor, key parameters of CF and BC, were calculated from NEE for the first time. The CF and BC of mangrove ecosystems were then refined using newly defined AFCS and yield factor. The proposed framework was applied to the whole mangrove forests in China to assess mangrove conservation efforts. The results showed that the average CF of mangrove forests is about 1000 M ha, which is lower than that of terrestrial forests, while the BC of mangroves is not as high as expected due to the limited area of mangroves. CF and BC vary along the coastline, whereby CF tends to decrease with decreasing latitude while BC remains high at low latitudes owing to the large mangrove area. There is no significant decreasing trend in CF, but BC increases with increasing mangrove area. The newly introduced ecological footprint accounting of mangrove ecosystems suggests that mangrove conservation in China should focus on ecosystem health and expand the area of forestable land. These findings will benefit future management of mangrove ecosystems in China and other countries. • Ecological footprint accounting was built for mangrove ecosystems. • Mangrove conservation contribute to decreasing carbon footprint and increasing bio-capacity. • Due to the limited area, mangrove ecosystems are not fully utilizing their carbon sink role in China. [ABSTRACT FROM AUTHOR]
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- 2023
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10. Does network infrastructure construction reduce energy intensity? Based on the "Broadband China" strategy.
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Hong, Junjie, Shi, Fangyuan, and Zheng, Yuhan
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ENERGY intensity (Economics) ,ECONOMIC development ,SUSTAINABLE development ,ENERGY consumption ,DIGITIZATION - Abstract
As one of the new economic forms, the digital economy has penetrated into all sub-sectors of the economy becoming a new engine for economic growth. Network infrastructure is the pillar and core driver for the development of the digital economy, getting increasingly evident and important. Meanwhile, green development has become a time trend for the more and more serious global climate problems. Thereinto, reducing energy intensity is an important starting point for achieving green development. The impact of network infrastructure on energy intensity should not be ignored. This article uses the "Broadband China" demonstration cities as a quasi-natural experiment to reflect the improvement of network construction and build a time-varying difference-in-differences (time-varying DID) model to explore the impact of network construction on Chinese prefecture-level energy intensity. The results show that: (1) The construction of network infrastructure can significantly reduce prefecture-level energy intensity, and this conclusion still holds after a series of robustness tests. (2) Network infrastructure construction will reduce prefecture-level energy intensity through the mediating effect of energy efficiency, market environment, and innovation. (3) The effect will be more obvious in Northeast China, with huge scale, high levels of human capital, perfect broadband user access, complex industrial structures and better financial development levels. We hope this research provides empirical evidence for improving the construction of network facilities and realizing the "Two-Wheel Drive" of digitizing and greening. • This study examines the relationship between network infrastructure and prefecture-level energy intensity. • We regard the "Broadband China" demonstration cities as a quasi-natural experiment. • The mechanism analysis shows that the effect occurs mainly through three possible paths. • We make heterogeneity analysis for five different perspectives. • Digitization effectively promotes the green development of cities. [ABSTRACT FROM AUTHOR]
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- 2023
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11. Wastewater treatment plant effluent discharge decreases bacterial community diversity and network complexity in urbanized coastal sediment.
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Dai, Tianjiao, Su, Zhiguo, Zeng, Yufei, Bao, Yingyu, Zheng, Yuhan, Guo, Huaming, Yang, Yunfeng, and Wen, Donghui
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SEWAGE disposal plants ,BACTERIAL communities ,COASTAL sediments ,BACTERIAL diversity ,MICROBIAL communities ,INDUSTRIAL wastes ,BODIES of water - Abstract
The wastewater treatment plant (WWTP) effluent discharge affects the microorganisms in the receiving water bodies. Despite the ecological significance of microbial communities in pollutant degradation and element cycling, how the community diversity is affected by effluent remains obscure. Here, we compared the sediment bacterial communities exposed to different intensities of WWTP effluent discharge in Hangzhou Bay, China: i) a severely polluted area that receives effluent from an industrial WWTP, ii) a moderately polluted area that receives effluent from a municipal WWTP, and iii) less affected area that inner the bay. We found that the sediment bacterial diversity decreased dramatically with pollution levels of inorganic nutrients, heavy metals, and organic halogens. Microbial community assembly model analysis revealed increased environmental selection and decreased species migration rate in the severely polluted area, resulting in high phylogenetic clustering of the bacterial communities. The ecological networks were less complex in the two WWTP effluent receiving areas than in the inner bay area, as suggested by the smaller network size and lower modularity. Fewer negative network associations were detected in the severely (6.7%) and moderately (8.3%) polluted areas than in the less affected area (16.7%), indicating more collaborative inter-species behaviors are required under stressful environmental conditions. Overall, our results reveal the fundamental impacts of WWTP effluents on the ecological processes shaping coastal microbial communities and point to the potential adverse effects of diversity loss on ecosystem functions. [Display omitted] • Bacterial community diversity decreases with coastal pollution levels. • Coastal WWTP effluent discharge inhibits species migration. • The impact of pollutants on bacterial diversity is greater than spatial distance. • WWTP effluent discharge decreases bacterial community network complexity. [ABSTRACT FROM AUTHOR]
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- 2023
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12. Sodium humate based double network hydrogel for Cu and Pb removal.
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Feng, Zhengyuan, Zheng, Yuhan, Wang, Haishuang, Feng, Chuanping, Chen, Nan, and Wang, Shizhong
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LEAD abatement , *ORBITAL hybridization , *ACID mine drainage , *X-ray photoelectron spectroscopy , *PHYSISORPTION , *WATER purification , *HYDROGELS - Abstract
Sodium humate (SH) is one of the derivatives humic substances, which can be utilized for heavy metal removal from water due to its containing plenty of functional groups. In this study, a double network hydrogel SH/polyacrylamide (SH/PAM) was synthesized by a simple free-radical polymerization and used for Cu2+ and Pb2+ removal from water. The adsorption process can be well described by Langmuir-Freundlich model, indicating that both physical and chemical adsorption were involved. X-ray photoelectron spectroscopy (XPS) characterization demonstrated that complexation was the main mechanism for the adsorption. Two-dimensional correlation analysis of FTIR (2D-FTIR-COS) results showed that the variation order of functional groups during Cu2+ and Pb2+ adsorption in the following order: COOH ≈ –C O > –OH > C–O and –COOH ≈ C–O > –C O > –OH, respectively. According to the density functional theory (DFT) calculation results, the O atom of SH in the COO− was the main adsorption site. Meanwhile, the adsorption energy of Pb2+ was more negative than that of Cu2+ and the orbital hybridization between O atom of SH and Pb2+ was denser than that of Cu2+, which suggested that SH/PAM had a stronger combining capacity for Pb2+ than Cu2+. Therefore, the adsorption capacity for Pb2+ was larger than Cu2+. Moreover, the removal efficiencies are 30.2% for Al, 98.79% for Cu, 99.0% for Fe, 17.2% for Mn, 93.4% for Pb, and 62.4% for Zn in actual acid mine drainage using 6 g L−1 adsorbent. Collectively, this study not only provided a new adsorbent for heavy metal removal but also explicated the mechanism of heavy metal removal by SH from molecule and electron perspective, which is helpful for the application of SH in the environmental field. [Display omitted] • The SH/PAM double network hydrogel was prepared for Cu and Pb removal. • The change of the functional groups during the adsorption process was identified. • The properties of electron and orbital of sodium humate were calculated. • The SH/PAM has a good removal efficiency for acid mine drainage. [ABSTRACT FROM AUTHOR]
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- 2023
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13. Deciphering the spatial and temporal evolution of urban anthropogenic resilience within the Yangtze River Delta urban agglomeration.
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Zhu, Zhiyuan, Zheng, Yuhan, and Xiang, Pengcheng
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URBAN research ,URBAN growth ,REGIONAL differences ,REGIONAL development - Abstract
Urban agglomeration, a highly evolved spatial form of integrated cities, has developed more rapidly with the growing interconnections among the cities. While benefiting from its invigorating prosperity, cities also confront palpable risks. Urban resilience and regional synergy are currently enduring more serious challenges. However, compelling research on urban agglomeration resilience is insufficiently conducted. This study proposes a four-dimensional evaluation index system (economic, political, social, and infrastructure) with a prone emphasis on political resilience, making up for the previous deficiency in interrogating political dimension. A basis for revealing the spatiotemporal evolution of the urban agglomeration resilience in the Yangtze River Delta urban agglomeration (YRD) is provided. Research results indicate that: (1) Urban resilience in YRD has increased significantly and continues to grow, with regional differences narrowing; (2) the YRD's resilience suggests a polycentric cluster distribution with resilience declining from the centre cities to surrounding ones; (3) the urban resilience gradually decreased from the east to the west, from the coast to the interior; and (4) cities with high economic and political resilience may be inferior in other two aspects, necessitating complementary capabilities amongst the cities. Understanding the spatiotemporal evolution of resilience is expected to further induce resilience development and urban synergy. [ABSTRACT FROM AUTHOR]
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- 2023
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14. Prevalence of small-sized microplastics in coastal sediments detected by multipoint confocal micro-Raman spectrum scanning.
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Liu, Dantong, Zheng, Yuhan, Chen, Lyujun, and Wen, Donghui
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- 2022
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15. Enhanced AHL-mediated quorum sensing accelerates the start-up of biofilm reactors by elevating the fitness of fast-growing bacteria in sludge and biofilm communities.
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Xiong, Fuzhong, Dai, Tianjiao, Zheng, Yuhan, Wen, Donghui, and Li, Qilin
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BIOFILMS , *QUORUM sensing , *MOVING bed reactors , *NEW business enterprises , *BACTERIAL communities , *RIBOSOMAL RNA - Abstract
• Ecological roles of AHL-mediated QS in shaping bacterial communities were revealed. • Enhanced QS stimulated fast-growing bacteria (r-strategists) in biofilm reactors. • The r-selected life strategy was tied to strong extracellular substance production. • Enhanced QS facilitated bacterial interactions, particularly cooperative ones. • QS-enhanced communities showed stronger stochasticity and more convergent dynamics. Quorum sensing (QS)-based manipulations emerge as a promising solution for biofilm reactors to overcome challenges from inefficient biofilm formation and lengthy start-ups. However, the ecological mechanisms underlying how QS regulates microbial behaviors and community assembly remain elusive. Herein, by introducing different levels of N-acyl-homoserine lactones, we manipulated the strength of QS during the start-up of moving bed biofilm reactors and compared the dynamics of bacterial communities. We found that enhanced QS elevated the fitness of fast-growing bacteria with high ribosomal RNA operon (rrn) copy numbers in their genomes in both the sludge and biofilm communities. This led to notably increased extracellular substance production, as evidenced by strong positive correlations between community-level rrn copy numbers and extracellular proteins and polysaccharides (Pearson's r = 0.529−0.830, P < 0.001). Network analyses demonstrated that enhanced QS significantly promoted the ecological interactions among taxa, particularly cooperative interactions. Bacterial taxa with higher network degrees were more strongly correlated with extracellular substances, suggesting their crucial roles as public goods in regulating bacterial interactions and shaping network structures. However, the assembly of more cooperative communities in QS-enhanced reactors came at the cost of decreased network stability and modularity. Null model and dissimilarity-overlap curve analysis revealed that enhanced QS strengthened stochastic processes in community assembly and rendered the universal population dynamics more convergent. Additionally, these shaping effects were consistent for both the sludge and biofilm communities, underpinning the planktonic-to-biofilm transition. This work highlights that QS manipulations efficiently drive community assembly and confer specialized functional traits to communities by recruiting taxa with specific life strategies and regulating interspecific interactions. These ecological insights deepen our understanding of the rules governing microbial societies and provide guidance for managing engineering ecosystems. [Display omitted] [ABSTRACT FROM AUTHOR]
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- 2024
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16. Divergent trends of urban thermal environmental characteristics in China.
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Zheng, Yuhan, Huang, Lin, and Zhai, Jun
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URBAN growth , *SMALL cities , *LAND surface temperature , *ARID regions , *METROPOLITAN areas , *GEOTHERMAL ecology - Abstract
Due to the rapid urbanization in China, urban expansion has gradually shifted from large cities to small cities, causing spatiotemporal changes in the urban thermal environment. The differential thermal environmental characteristics of 334 cities at different hierarchy caused by urbanization are investigated in this study. Then, the spatiotemporal changes of land surface temperature (LST), albedo, and emissivity among urban areas and their surrounding buffer areas are analyzed during 2000–2015. We found that the urban warming effect is usually prominent in the daytime, with an obvious seasonal differentiation between 0.32 °C[0.27,0.38] in summer and -0.14 °C[-0.20,-0.07] in winter. The nighttime warming effect during summer resembles that in winter, in the range 0.23–0.25 °C. In addition, the number of cities with intensifying trends of the warming effect in summer daytime account for 50% of the total cities, but only 9% in winter nighttime, 23% in summer nighttime, and 25% in winter daytime. Large cities usually have obvious warming effects compared with small cities. But the highest warming effect is found in megacities during the daytime and in medium cities during the nighttime. In southern subtropical cities, the warming of urban zones is high in the daytime and low in the nighttime, while it is opposite in arid and semiarid regions, especially in winter. The negative correlations between the difference of surface albedo (emissivity) and LST in megacities and metropolitan areas emphasize that nighttime warming primarily results from radiation absorption and release affected by urbanization. This study may advance the understanding of the heterogeneity in the warming effects of different cities in China and support policy formulation and regulation to adapt to urban warming. [ABSTRACT FROM AUTHOR]
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- 2021
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17. Opportunities for blue carbon strategies in China.
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Wu, Jiaping, Zhang, Haibo, Pan, Yiwen, Krause-Jensen, Dorte, He, Zhiguo, Fan, Wei, Xiao, Xi, Chung, Ikkyo, Marbà, Nuria, Serrano, Oscar, Rivkin, Richard B., Zheng, Yuhan, Gu, Jiali, Zhang, Xiujuan, Zhang, Zhaohui, Zhao, Peng, Qiu, Wanfei, Chen, Guangcheng, and Duarte, Carlos M.
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MANGROVE ecology ,MANGROVE plants ,CLIMATE change mitigation ,MARINE algae culture ,SEAGRASS restoration ,AQUACULTURE ,RECLAMATION of land - Abstract
Blue Carbon (BC) strategy refers to the approaches that mitigate and adapt to climate change through the conservation and restoration of seagrass, saltmarsh and mangrove ecosystems and, in some BC programs, also through the expansion of seaweed aquaculture. The major losses of coastal habitats in combination with the commitments of China under the Paris Agreement provide unique opportunity and necessity to develop a strong Chinese BC program. Here, we (1) characterize China's BC habitats, examine their changes since 1950 along with the drivers of changes; (2) consider the expansion of seaweed aquaculture and how this may be managed to become an emerging BC resource in China, along with the engineering solutions required to enhance its potential; and (3) provide the rationale and elements for BC program in China. We find China currently has 1326–2149 km
2 wild and 2–15 km2 created mangrove, saltmarsh and seagrass habitats, while 9236–10059 km2 (77–87%) has been lost since 1950, mainly due to land reclamation. The current area of farmed seaweed habitat is 1252–1265 km2 , which is close to the area of wild mangrove, saltmarsh and seagrass habitats. We conclude that BC strategies have potentials yet to be fully developed in China, particularly through climate change adaptation benefits such as coastal protection and eco-environmental co-benefits of seaweed farming such as habitat creation for fish and other biota, alleviation of eutrophication, hypoxia and acidification, and the generation of direct and value added products with lower environmental impact relative to land-based production. On this basis, we provide a roadmap for BC strategies adjusted to the unique characteristics and capacities of China. Blue Carbon (BC) plays important roles in climate change mitigation/adaptation. In this paper, we 1) characterize China's BC habitats and examine their changes since 1950 along with the drivers of changes; 2) consider the expansion of seaweed aquaculture and how this may be managed to become an emerging BC resource in China, along with the engineering solutions required to enhance its potential; 3) provide the rationale and elements for BC program in China; and 4) draw a roadmap for BC strategies adjusted to the unique characteristics and capacities of China.Porphyra farm in Dongtou, Wenzhou city, Zhejiang province, China. Image 1 • China's Blue Carbon (BC) habitats, changes and the drivers of changes since 1950. • Potential BC resources, seaweed aquaculture expansion with engineering solutions. • BC Benefits for climate adaptation and co-benefits for environment and economy. • Great potential of China's BC strategies through climate change adaptation benefits. • A roadmap for BC strategies adjusted to the China's characteristics and capacities. [ABSTRACT FROM AUTHOR]- Published
- 2020
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18. Farmland transition in China and its policy implications.
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Ma, Li, Long, Hualou, Tu, Shuangshuang, Zhang, Yingnan, and Zheng, Yuhan
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LAND management ,K-means clustering ,LAND use ,DEMAND function ,PHASE transitions - Abstract
• A theoretical analysis framework of farmland transition was established. • Spatio-temporal evolution characteristics of farmland transition in China were analyzed. • The phases of farmland transition were divided quantitatively. • Policy implications concerning land use management and optimal regulation were proposed. China's land use structure is closely related to its economic development. Based on the theoretical analysis framework of China's farmland transition (FT), this paper establishes an evaluation index system for quantifying FT from two dimensions, the dominant transition and recessive transition, and uses K-means clustering to quantitatively divide the phases of FT in China over the past four decades. The results show that the FT in China has experienced several phases from slow transition, rapid transition, to steady transition and innovation transition, and demonstrates clear regional differences. The dominant transition phase, social and ecological farmland transition, mainly occurred during 2000–2010. The economic farmland transition occurred earlier, during 1990–2000. Spatially, the economic farmland transition gradually shifted from the southeast coastal area to the inland. The "structure-function" transition of China's farmland in the past four decades can be divided into four phases: the preliminary exploration and development phase, the steady development and expansion phase, the market-oriented reform and deepening phase, and the reform and innovation phase. Finally, relevant policy implications and suggestions were proposed for the optimal management and regulation of farmland according to the characteristics of FT, its challenges and people's new demand for farmland functions. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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19. Antibiotics in coastal water and sediments of the East China Sea: Distribution, ecological risk assessment and indicators screening.
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Li, Feifei, Chen, Lyujun, Chen, Weidong, Bao, Yingyu, Zheng, Yuhan, Huang, Bei, Mu, Qinglin, Wen, Donghui, and Feng, Chuanping
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ECOLOGICAL risk assessment ,COASTAL sediments ,TERRITORIAL waters ,ANTIBIOTICS ,COASTAL zone management ,CLINDAMYCIN - Abstract
The distribution of 77 antibiotics in the coastal water and sediment from 3 bays of the East China Sea was investigated. There were 43 and 25 antibiotics detected with total concentrations of 30.8–2106.1 ng/L and 2.2–99.9 ng/g in water and sediment, respectively. Approximately 83.0% and 85.4% of the individual antibiotic concentrations were lower than 5.0 ng/L in water and 1.0 ng/g in sediment. Clindamycin (1.2–1507.9 ng/L, mean 183.8 ng/L) and erythromycin (ND–45.2 ng/g, mean 3.4 ng/g) were the most abundant in water and sediment, respectively. Ecological risk assessment revealed that the joint toxicity was enhanced when multiple antibiotics were present simultaneously. A decrease in the total antibiotic concentration and the ecological risk in water was observed from nearshore to offshore. Three antibiotics (sulfamethoxypyridazine, sulfamethoxazole and cinoxacin) were selected to be prioritized based on ecological risks for antibiotics monitoring and management of the coastal water in the East China Sea. Unlabelled Image • Distribution of 77 antibiotics were investigated in the coastal water and sediment. • Indicators were screened from multiple antibiotics based on ecological risks. • Coastal antibiotic contamination was proven to be acquired rather than innate. • Ecological risk of antibiotics decreased as the offshore distance increased. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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20. Screening and identification: Evaluating the transformation suitability of rural complexes through industrial resource potential in Changsha, China.
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Yuan, Zheng, Xu, Feng, Yin, Yicheng, Yin, Jingwen, and Zheng, Yuhan
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INDUSTRIAL capacity , *GREEN infrastructure , *GRAVITY model (Social sciences) , *RURAL development , *INNER cities , *IDENTIFICATION , *TOURISM websites - Abstract
Promoting sustainable development in rural areas through industrial transformation has emerged as a global consensus. The rural complex, characterized by its integration of industrial elements, serves as an advantageous target for China's rural transformation and development. However, the lack of accurate assessment and identification of industrial resource potential has impeded the progress and growth of rural complexes. Therefore, there is a pressing need for an evaluation framework that includes screening and identification functionalities to effectively guide the industrial transformation of rural complexes. Commencing with a precise definition of rural complexes and an explanation of relevant policies, this study combines qualitative theoretical constructs with quantitative multi-criteria decision-making models. Additionally, the study incorporates the gravity model to measure the impact of urban radiation on rural areas. The resulting framework for evaluating industrial resource potential consists of "3 + 7" Modules. Subsequently, utilizing Changsha as a case study, the effectiveness of the evaluation framework is verified across 804 administrative villages. The findings classify these villages into three regions, revealing a circular distribution pattern characterized by decay from the urban center towards the periphery, except for education. Moreover, all modules demonstrate significant spatial autocorrelation. Infrastructure and the ecological environment exert a substantial influence on other industries, while notable synergies exist among the Internet, culture, tourism, and science & technology innovation. Finally, based on the findings, five development suggestions are proposed, focusing on spatial integration and construction mechanisms. The study strengthens the theoretical understanding of rural complexes, provide a practical decision-making tool for project approval processes and the diagnosis of rural industries, and enhance the strategic investment approach toward rural revitalization. • A new evaluation framework for rural complex based on industrial resource potential. • The staged and modular evaluation criteria under internal and external influences. • The gravity model was used to determine the degree of the economic impact of a central city. • Some industrial resources showed a positive correlation and a circle-like distribution. • The resource potential of 804 villages in Changsha was calculated and then analyzed. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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21. Subtype distribution and genetic characterizations of Blastocystis in pigs, cattle, sheep and goats in northeastern China's Heilongjiang Province.
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Wang, Jianguang, Gong, Baiyan, Yang, Fengkun, Zhang, Weizhe, Zheng, Yuhan, and Liu, Aiqin
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BLASTOCYSTIS , *ZOONOSES , *NUCLEOTIDE sequencing , *POLYMERASE chain reaction , *RIBOSOMAL RNA , *INTESTINAL diseases - Abstract
Blastocystis is a common protozoan found in the surveys of human and animal fecal specimens. Extensive genetic diversity has been observed within the genus Blastocystis. At least 17 subtypes (ST) have been identified in mammals and birds, nine of which (ST1 to ST9) have been identified in humans. In China, although there have been a few reports on Blastocystis infection in humans and many animal species, no epidemiological data are available in either humans or animals in northeastern China's Heilongjiang Province. To determine infection rates and subtype distributions of Blastocystis in pigs, cattle, sheep and goats, to understand genetic characterizations and to assess zoonotic possibility of Blastocystis isolates, 337 fecal specimens from livestock (68 from pigs, 147 from cattle, 109 from sheep and 13 from goats) were collected in northeastern China's Heilongjiang Province. Each of them was detected for Blastocystis by PCR amplification of the partial SSU rRNA gene. An average infection rate of Blastocystis was 7.7% (26/337), and the highest infection rate was found in 9.5% (14/147) in cattle, followed by 8.8% (6/68) in pigs and 5.5% (6/109) in sheep. There was an absence of Blastocystis in goats. Five Blastocystis subtypes were identified: ST5 (n = 6) in pigs; ST3 (n = 2), ST10 (n = 10) and ST14 (n = 2) in cattle; ST1 (n = 1), ST5 (n = 1), ST10 (n = 3) and ST14 (n = 1) in sheep. 38.5% (10/26) of Blastocystis isolates belong to potentially zoonotic subtypes based on the previous findings of ST1, ST3 and ST5 in humans. This is the first report of Blastocystis in pigs, cattle and sheep in northeastern China's Heilongjiang Province. ST1, ST5 and ST14 were identified in sheep for the first time. Due to the low infection rate of Blastocystis and the small percentage of potentially zoonotic subtypes in these livestock, there is a minimal risk of zoonotic transmission of Blastocystis . [ABSTRACT FROM AUTHOR]
- Published
- 2018
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22. The impact of farmland use transition on rural livelihood transformation in China.
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Chen, Kunqiu, Wang, Yuxia, Li, Ninghui, Xu, Yilan, Zheng, Yuhan, Zhan, Xiaolin, and Li, Qixuan
- Subjects
- *
AGRICULTURAL development , *RURAL development , *LAND use , *AGRICULTURAL productivity , *ECONOMETRIC models - Abstract
Land use transitions are an important research area in land system science. In seeking a feasible way to improve rural residents' livelihoods and rural development, this paper explores the mechanism and effects of farmland use transition on rural livelihood transformation from the perspective of the human-land relationship. The theoretical framework of rural livelihood transformation as affected by farmland use transition is established, and econometric models are used to test the effects based on empirical panel data from China for the period 2000–2017. The major conclusions are drawn as follows. In essence, farmland use transition is the redistribution of agricultural productivity on farmland, and rural livelihood transformation is a process of long-term and trend transformation of rural residents' livelihood capital, livelihood structure, and livelihood pattern. Land use transitions boost the transformation of rural livelihood by regulating the rural human-land interactive relationship and substitutional relationship of elements in agricultural development. For every 1% increase in farmland management scale transition and farmland efficiency transition, rural livelihood transformation can be improved by 3.748% and 3.854%, respectively. The direction and intensity of the impact of farmland use transition on rural livelihood transformation differ by area and topographic conditions. Furthermore, people's livelihood finances and farmers' planting decisions regulate the effects of farmland use transition on rural livelihood transformation. The authors argue that regulating land use transitions can be an important component of policy-making to promote rural livelihoods transformation, and rural development transformation. • Theoretical framework for rural livelihood transformation affected by farmland use transition is established. • For every 1% increase in farmland scale and efficiency transition, rural livelihood transformation can be improved by 3.748% and 3.854%, respectively. • Impact of farmland use transition on rural livelihood transformation is heterogeneous in different areas and terrains. • People's livelihood finances and farmers' planting decisions will regulate the effect of farmland use transition on rural livelihoods transformation. • Regulating land use transition can be an important component of policy-making to promote rural livelihood transformation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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23. Industrial effluents boosted antibiotic resistome risk in coastal environments.
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Su, Zhiguo, Wen, Donghui, Gu, April Z., Zheng, Yuhan, Tang, Yushi, and Chen, Lyujun
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INDUSTRIAL wastes , *HORIZONTAL gene transfer , *ANTIBIOTICS , *WATER pipelines , *SEWAGE disposal plants , *COASTAL sediments - Abstract
[Display omitted] • Coastal area is an ideal platform for studying antibiotic resistome from the "One Health" perspective. • Land-based wastewater disposal exports ARGs with higher diversity and abundance to sea. • Industrial WWTP effluent might be the source of highest antibiotic resistome risk. • mcr-4 and mcr-5 derived from industrial effluent were enriched in the ERA sediments. • HGT potential was higher between microbiome of industrial effluent and its ERA sediments. Wastewater treatment plants (WWTPs) have been regarded as an important source of antibiotic resistance genes (ARGs) in environment, but out of municipal domestic WWTPs, few evidences show how environment is affected by industrial WWTPs. Here we chose Hangzhou Bay (HZB), China as our study area, where land-based municipal and industrial WWTPs discharged their effluent into the bay for decades. We adopted high-throughput metagenomic sequencing to examine the antibiotic resistome of the WWTP effluent and coastal sediment samples. And we proposed a conceptual framework for the assessment of antibiotic resistome risk, and a new bioinformatic pipeline for the evaluation of the potential horizontal gene transfer (HGT) frequency. Our results revealed that the diversity and abundance of ARGs in the WWTP's effluent were significantly higher than those in the sediment. Furthermore, the antibiotic resistome in the effluent-receiving area (ERA) showed significant difference from that in HZB. For the first time, we identified that industrial WWTP effluent boosted antibiotic resistome risk in coastal sediment. The crucial evidences included: 1) the proportion of ARGs derived from WWTP activated sludge (WA) was higher (14.3 %) and two high-risky polymyxin resistance genes (mcr-4 and mcr-5) were enriched in the industrial effluent receiving area; 2) the HGT potential was higher between resistant microbiome of the industrial effluent and its ERA sediment; and 3) the highest resistome risk was determined in the industrial effluent, and some biocide resistance genes located on high-risky contigs were related to long-term stress of industrial chemicals. These findings highlight the important effects of industrial activities on the development of environmental antimicrobial resistance. [ABSTRACT FROM AUTHOR]
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- 2023
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24. Ozone oxidation of 2,4,6-TCP in the presence of halide ions: Kinetics, degradation pathways and toxicity evaluation.
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Xu, Ranyun, Ren, Hang, Chi, Tongtong, Zheng, Yuhan, Xie, Yawei, Tian, Jinping, and Chen, Lyujun
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- *
TRICHLOROPHENOL , *TOXICITY testing , *CHLORIDE ions , *OZONE , *ENVIRONMENTAL degradation , *HALIDES , *IONS - Abstract
2,4,6-Trichlorophenol (2,4,6-TCP) is extensively consumed in industrial production and may cause environmental damages. The effect of halide ions on the decomposition of 2,4,6-TCP has often been overlooked. In this study, the bromide ion was found to have a stronger negative impact on 2,4,6-TCP degradation than chloride ion in the O 3 system, and led to the formation of adsorbable organic halogens (AOX). Kinetic modeling demonstrated that the concentration of various radicals was largely depended on the solution pH, and stronger basicity not only contributed to the mineralization of 2,4,6-TCP, but also inhibited the formation of halogenated by-products. Combining the intermediate identification and quantum chemical calculation, the degradation pathways of 2,4,6-TCP during ozone oxidation process were proposed. The toxicity test and ECOSAR simulation demonstrated that the acute toxicity of some 2,4,6-TCP degradation intermediates was relatively higher than their parent compound. With high concentrations of halide ions, the ozone-treated solution showed greater toxicity than the originator 2,4,6-TCP solution. These results illustrate that the ozone treatment of the halide-containing wastewater may cause potential ecological hazards and its application needs to be more cautious. [Display omitted] • Cl− and Br− pose an adverse effect on 2,4,6-TCP degradation in the O 3 system. • Kinetics of the generation of reactive species are modelled during ozonation. • Possible degradation pathways of 2,4,6-TCP are proposed. • With halide ions, the toxicity of 2,4,6-TCP solution increases after O 3 treatment. • There is a synergistic toxic effect between 2,4,6-TCP degradation intermediates. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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25. The contribution of ocean-based solutions to carbon reduction in China.
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Feng, Cuicui, Ye, Guanqiong, Jiang, Qutu, Zheng, Yuhan, Chen, Guangwei, Wu, Jiaping, Feng, Xuehao, Si, Yulin, Zeng, Jiangning, Li, Peiliang, and Fang, Kai
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- 2021
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26. Identification of the priority antibiotics based on their detection frequency, concentration, and ecological risk in urbanized coastal water.
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Li, Feifei, Chen, Lyujun, Bao, Yingyu, Zheng, Yuhan, Huang, Bei, Mu, Qinglin, Feng, Chuanping, and Wen, Donghui
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Antibiotics have raised significant concern as emerging pollutants for their increasing consumption, persistent input, and potential threat to ecological environment. Due to low concentrations and various types in coastal water, simultaneous quantification of all kinds of antibiotics is time-consuming and costly. In order to make antibiotic regular monitoring in coastal water possible, identifying the priority antibiotics in the environment is essential. Here, a method for screening the priority antibiotics in coastal water was proposed, considering individual antibiotic concentration, the positive correlation between individual and total antibiotic concentration, the detection frequency, and obvious ecological risk. Taking coastal water of the East China Sea as an example, on a list of 77 target antibiotics, 7 (SMX, TMP, SCP, SMP, CNX, ATM, and ETM) and 4 (SMX, SCP, SMP, and CNX) antibiotics were selected to be the priority antibiotics in 2017 and 2018, respectively. Furthermore, the 4 priority antibiotics in 2018 were all involved in the 7 priority antibiotics in 2017. The sum of the priority antibiotic concentrations accounted for 0.8% and 23.2% of total antibiotic concentrations, and the sum of their RQ accounted for 69.2% and 66.8% of total RQ values in 2017 and 2018, respectively. Among the above 7 priority antibiotics, ATM is mainly used in human clinical, SMX, SCP, and SMP are mainly consumed in veterinary medicine, TMP, CNX, and ETM are commonly used for humans and animals. The proposed method might provide an important reference for the monitoring and management of antibiotic pollution in coastal water. Unlabelled Image • Methods for determining priority antibiotics lack criterion in coastal water. • Detection frequency, concentration and ecological risk were considered simultaneously. • Both individual and combined toxicity of multiple antibiotics were taken into account. • Priority antibiotics in a typical coastal water of China were first proposed. [ABSTRACT FROM AUTHOR]
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- 2020
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27. The hidden mechanism of chemical fertiliser overuse in rural China.
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Zhang, Yingnan, Long, Hualou, Wang, Mark Yaolin, Li, Yurui, Ma, Li, Chen, Kunqiu, Zheng, Yuhan, and Jiang, Tianhe
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FERTILIZERS , *FARM size , *FARMS , *PEER pressure , *LAND use - Abstract
A comprehensive understanding of the reasons for over-fertilisation is critical to agro-environment sustainability, especially for the fast-growing farming areas under urbanisation. Previous studies are more quantitatively biased and in most cases, merely focus on demographical, economic and political factors whilst excluding in-depth qualitative and holistic investigation. To address this gap, this paper attempts to construct a conceptual framework to investigate the hidden mechanism of chemical fertiliser overuse through an empirical study in the Dancheng county of China. Such a framework is based on Kollmuss and Agyeman (2002), and Blake's (1999) works, but incorporates demographical factors and external barriers for explaining the awareness-behaviour gap. Results indicate that environmental awareness is not necessarily related with chemical fertiliser overuse as the reasons for farmers' inappropriate behaviours are embedded within an intricate network of economic, social-cultural and policy-influenced factors incorporating labour and time constraints, risk-averse decisions, intergenerational division, farm size, attachment to instant gratification, land attachment, peer pressure, distortion of agricultural and land use policies, which has roots in the agricultural marginalisation and urban-rural dichotomy. Based on the results, policy recommendations are provided. • There is a paucity of in-depth understanding of Chinese farmers' over-fertilisation behaviour. • A comprehensive analytical framework was constructed to analyse the fertiliser overuse behaviour. • Environmental awareness is not necessarily related with chemical fertiliser overuse. • Farmers' overuse behaviour is embedded within an intricate network of multiple factors. [ABSTRACT FROM AUTHOR]
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- 2020
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28. Research on the redox behavior changes of humic-like substances wastewater during electrochemical oxidation process and using the treated effluent to improve the heavily contaminated soil: Taking petroleum hydrocarbon contaminated soil as example.
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Deng, Yang, Wen, Jianping, Zhu, Xu, Chen, Nan, Feng, Chuanping, Zheng, Yuhan, Wang, Haishuang, Chen, Fangxin, and Gao, Yu
- Subjects
- *
BEHAVIOR , *SOIL pollution , *BEHAVIORAL research , *SEWAGE , *ORGANIC geochemistry , *PETROLEUM , *HUMUS - Abstract
Humic-like substance-containing wastewater is the main type of wastewater. This study investigated the redox behavior of organic matter during the treatment process of humic-like substances by electrochemical oxidation as well as the feasibility of improving heavily polluted soil (using petroleum hydrocarbon contaminated soil as an example) with the effluent from different treatment levels. Molecular spectrum analysis and electrochemical analysis showed that the quinone and aromatic groups of the humic-like substances were degraded by electrochemical oxidation, directly leading to a decreased electron donating capability. Meanwhile, this process promoted the formation of protein-like substances and fulvic-like substances, and was accompanied by an improved electron accepting capability. Since the increasing amount of electron accepting capability was greater than the decreasing amount of electron donating capability throughout the whole process, the electrochemical oxidation process increased the total electron transfer capacity of the organic matter. In addition, bioinformatic analysis shows that the organic matter in the treated effluent enhanced the activity and abundance of dominant indigenous microorganisms in petroleum hydrocarbon contaminated soil, which is advantageous to the natural remediation of heavily polluted soils based on degradation by indigenous bacteria. This study provides a detailed basis for understanding the electrochemical degradation process of humic-like substances as well as the resource utilization of residual organic matter after electrochemical treatment of humic-like substance-containing wastewater. Image 1 • Formation of protein-like substances and fulvic-like substances can increase EAC. • The removal of quinone and aromatic group lead to the reduction of EDC. • Electrochemical oxidation process can increase the total ETC of organic matters. • Treated effluent enhanced the growth of indigenous microorganisms for PHCS. • Electrochemical technology is conducive to the further utilization of treated effluent. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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29. Degradation of nitrogen-containing refractory organic wastewater using a novel alternating-anode electrochemical system.
- Author
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Deng, Yang, Chen, Nan, Feng, Chuanping, Wang, Haishuang, Zheng, Yuhan, Chen, Fangxin, Lu, Wang, Kuang, Peijing, Feng, Hanguang, Gao, Yu, and Hu, Weiwu
- Abstract
This study presented a novel alternating-anode electrochemical system (AAES) based on single electrolytic cell for the treatment of nitrogen-containing refractory organic wastewater (NOW). The core of AAES lies in the alternating working of iron anode and DSA anode to integrate different electrochemical processes. The biologically treated landfill leachate (BTLL) was selected as a practical NOW for assessing the performance of AAES. The results indicated that after 140 min of electrolytic reaction, the removal efficiency of chemical oxygen demand and total nitrogen (TN) using AAES was found to be 76.9 and 98.9%, respectively. The main component of dissolved organic matter (DOM) in BTLL included humic-like substances, which could be degraded into small-molecule DOM, such as fulvic-like substances and protein-like substances, by available chlorine and hydroxyl radicals present in AAES. Cathode reduction (NO x −-N → NH 4 +–N and N 2) under iron anode and indirect oxidation (NH 4 +–N → N 2) under DSA anode were the main pathways to remove TN from NOW. Owing to the redox conditions created by the alternating anodes, the main stable crystalline forms of precipitates obtained from AAES were Fe 3 O 4 and γ-Fe 2 O 3 , which could be separated by using the external magnetic field. The findings of this study may provide a feasible solution for the advanced electrochemical treatment of NOW in a single electrolytic cell as well as rapid separation of precipitates. Unlabelled Image • AAES can simultaneously remove COD and TN in a single electrolytic cell. • AAES can promote magnetic force formation for electro-coagulation precipitates. • AAES can accelerate TN removal by decreasing the conversion of NO x −-N to NH 4 +-N. • Obtained precipitate under Fe and DSA anode was Fe 3 O 4 and γ-Fe 2 O 3 , respectively. • The available chlorine played a greater role in promoting the removal of COD. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
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