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Publications (8)19.09 Total impact

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    ABSTRACT: Discovering ways in which to increase the sustainability of the metabolic processes involved in urbanization has become an urgent task for urban design and management in China. As cities are analogous to living organisms, the disorders of their metabolic processes can be regarded as the cause of "urban disease". Therefore, identification of these causes through metabolic process analysis and ecological element distribution through the urban ecosystem's compartments will be helpful. By using Beijing as an example, we have compiled monetary inputoutput tables from 1997, 2000, 2002, 2005, and 2007 and calculated the intensities of the embodied ecological elements to compile the corresponding implied physical input-output tables. We then divided Beijing's economy into 32 compartments and analyzed the direct and indirect ecological intensities embodied in the flows of ecological elements through urban metabolic processes. Based on the combination of input-output tables and ecological network analysis, the description of multiple ecological elements transferred among Beijing's industrial compartments and their distribution has been refined. This hybrid approach can provide a more scientific basis for management of urban resource flows. In addition, the data obtained from distribution characteristics of ecological elements may provide a basic data platform for exploring the metabolic mechanism of Beijing.
    Frontiers of Earth Science 03/2014; 8(2). · 0.52 Impact Factor
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    ABSTRACT: The resource and environmental issues that are emerging as a result of rapid urban development have made the study of urban metabolism increasingly important. However, past studies on urban metabolism have focused primarily on the system's external characteristics rather than on the internal production and consumption processes. To better understand the underlying mechanisms of urban metabolic processes, we present a method through which one can examine and characterize the production and consumption flows intrinsic to an urban metabolic system. Drawing upon several analytical procedures from ecological network analysis, we applied the method to a case study in Beijing, China. We collected a large body of statistical data and used it to account for the material flows inside Beijing's system from 1998 to 2007, thereby providing a quantitative network model of the system. We found that the paths between different components of Beijing's urban metabolic system remain simple, that there is insufficient cycling, and that the city's lack of internal environmental support capacity forces it to depend heavily on inputs from the external environment. These results suggest that the city needs to develop the reducer (recycling) component of its hierarchy to reduce the double pressure on its internal environment created by demands for resource supply and for absorption and recycling of wastes and other materials. This will help Beijing to achieve more sustainable development.
    Landscape and Urban Planning 01/2014; 121:19–33. · 2.31 Impact Factor
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    ABSTRACT: The efficiency of urban metabolic processes depends on the degree of mutualism of these processes throughout the metabolic system and on the value gained by each compartment within the system. This can be assessed by means of ecological network-based synergism analysis. In this paper, we used material-flow accounting methods to account for the exchanges of resources and wastes among the compartments of an urban system. Using a seven-compartment urban metabolic network model of Beijing, China, as a case study, we examined the degree of synergism of the compartments, determined the nature of the resulting ecological relationships, and determined the flow of utility to each compartment within the system. The results revealed which types of ecological relationship contributed most to the system (here, exploitation) and identified the key compartments that decreased the system's degree of synergism. The results provide theoretical and empirical support for the development of policies designed to promote healthy development of Beijing's urban metabolic system.
    Ecological Modelling 01/2014; 272:188–197. · 2.07 Impact Factor
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    ABSTRACT: If cities are considered as "superorganisms", then disorders of their metabolic processes cause something analogous to an "urban disease". It is therefore helpful to identify the causes of such disorders by analyzing the inner mechanisms that control urban metabolic processes. Combining input-output analysis with ecological network analysis lets researchers study the functional relationships and hierarchy of the urban metabolic processes, thereby providing direct support for the analysis of urban disease. In this paper, using Beijing as an example, we develop a model of an urban metabolic system that accounts for the intensity of the embodied ecological elements using monetary input-output tables from 1997, 2000, 2002, 2005, and 2007, and use this data to compile the corresponding physical input-output tables. This approach described the various flows of ecological elements through urban metabolic processes and let us build an ecological network model with 32 components. Then, using two methods from ecological network analysis (flow analysis and utility analysis), we quantitatively analyzed the physical input-output relationships among urban components, determined the ecological hierarchy of the components of the metabolic system, and determined the distribution of advantage-dominated and disadvantage-dominated relationships, thereby providing scientific support to guide restructuring of the urban metabolic system in an effort to prevent or cure urban "diseases".
    Science of The Total Environment 09/2013; 468-469C:642-653. · 3.16 Impact Factor
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    ABSTRACT: Cities can be modelled as giant organisms, with their own metabolic processes, and can therefore be studied using the same tools used for biological metabolic systems. The complicated distribution of compartments within these systems and the functional relationships among them define the system's network structure. Taking Beijing as an example, we divided the city's internal system into metabolic compartments, then used ecological network analysis to calculate a comprehensive utility matrix for the flows between compartments within Beijing's metabolic system from 1998 to 2007 and to identify the corresponding functional relationships among the system's compartments. Our results show how ecological network analysis, utility analysis, and relationship analysis can be used to discover the implied ecological relationships within a metabolic system, thereby providing insights into the system's internal metabolic processes. Such analyses provide scientific support for urban ecological management.
    Environmental Pollution 07/2012; 170:169-76. · 3.73 Impact Factor
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    ABSTRACT: Uncontrolled socioeconomic development has strong negative effects on the ecological environment, including pollution and the depletion and waste of natural resources. These serious consequences result from the high flows of materials and energy through a socioeconomic system produced by exchanges between the system and its surroundings, causing the disturbance of metabolic processes. In this paper, we developed an ecological network model for a societal system, and used China in 2006 as a case study to illustrate application of the model. We analyzed China's basic metabolic processes and used ecological network analysis to study the network relationships within the system. Basic components comprised the internal environment, five sectors (agriculture, exploitation, manufacturing, domestic, and recycling), and the external environment. We defined 21 pairs of ecological relationships in China's societal metabolic system (excluding self-mutualism within a component). Using utility and throughflow analysis, we found that exploitation, mutualism, and competition relationships accounted for 76.2, 14.3, and 9.5% of the total relationships, respectively. In our trophic level analysis, the components were divided into producers, consumers, and decomposers according to their positions in the system. Our analyses revealed ways to optimize the system's structure and adjust its functions, thereby promoting healthier socioeconomic development, and suggested ways to apply ecological network analysis in future socioeconomic research.
    Journal of Environmental Management 01/2012; 93(1):254-63. · 3.06 Impact Factor
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    ABSTRACT: Obtaining cost-effective iron (oxyhydr)oxide nanocrystallines is the essential prerequisite for their future extensive applications in environmental remediation, such as the removal of heavy metals from contaminated waters. Here, various phases of iron (oxyhydr)oxide nanocrystallines were simply synthesized from the phase-controlled transformation of amorphous hydrous ferric- or ferrous-oxide in thermal solution with a certain ethanol/water ratio and with the presence of oleic acid. According to this method, goethite nanorods in diameter of 3–4nm, hematite nanocubes sized 20–30nm, and magnetite nanoparticles in diameter of 6–7nm were successfully obtained. The final products of this transformation can be conveniently controlled by adjusting the reaction parameters, such as pH, temperature, and ethanol/water ratio. Due to the enhanced specific surface area and probably the modifications of the surface structure of nanocrystallines, the as-synthesized goethite nanorods and magnetite nanoparticles demonstrated extremely strong As(III) affinity, with 5.8 and 54 times of As(III) adsorption, respectively, higher than the micron-sized relatives. The cost-effective feature of as-synthesized nanocrystallines and their remarkably enhanced affinity toward arsenic made them potentially applicable for the removal of arsenic and such like heavy metals from the contaminated environment. KeywordsPreparation–Iron oxyhydroxides–Nanocrystallines–Arsenic removal–Environmental remediation
    Journal of Nanoparticle Research 13(7):2853-2864. · 2.18 Impact Factor
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    Yan Zhang, Hong Liu, Bin Chen
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    ABSTRACT: The resource shortages and environmental problems that cities face can be attributed to their increasing metabolic throughflow and their metabolic inefficiency. To support urban ecological management, it is necessary to identify the main metabolic actors responsible for these problems and analyze the characteristics of their metabolic structure. In this paper, we divide a typical urban metabolic system into seven components. Using material-flow analysis, we accounted for the amounts of resources and wastes transferred among the system's components and between the system and its environment, using Beijing from 1998 to 2007 as a case study. We used four indicators (metabolic scale, intensity, efficiency, and impact) to represent the inner structural characteristics of the urban metabolic system and analyzed the system based on the proposed indicators. The results provide scientific support for identifying the key metabolic actors responsible for urban metabolic disorders by accurately characterizing the city's metabolic status.
    Ecological Modelling 252:106–113. · 2.07 Impact Factor