The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 k...The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 km long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique,spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely: Agriculture patches were abundant and less fragmented; the urban land use types were extensive,having many small patches and highly fragmented.展开更多
Mesocyclops Leukarti of zooplankton propagates excessively in eutrophic water body and it can not be effectively inactivated by the conventional process in drinking waterworks for its special surface structure. In thi...Mesocyclops Leukarti of zooplankton propagates excessively in eutrophic water body and it can not be effectively inactivated by the conventional process in drinking waterworks for its special surface structure. In this paper, a study of removal efficiency on Mesocyclops Leukarti with chlorine dioxide in a drinking waterworks was performed. Bench scale results showed that chlorine dioxide is more effective against Mesocyclops Leukarti. And Mesocyclops Leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation cooperated with the conventional process during the full scale study. The chlorite, by-product of prechlorine dioxide, was constant at 0.45 mg/L after filtration, which was lower than the critical value of the USEPA. GC-MS examination and Ames test showed that the quantity of organics and the mutagenicity in the water treated by chlorine dioxide is obviously less than that of prechlorination.展开更多
In this works, artificial neural network is com-bined with wavelet analysis for the forecast of solar irradiance. This method is characteristic of the preprocessing of sample data using wavelet transformation for the ...In this works, artificial neural network is com-bined with wavelet analysis for the forecast of solar irradiance. This method is characteristic of the preprocessing of sample data using wavelet transformation for the forecast, i.e., the data se-quence of solar irradiance as the sample is first mapped into several time-frequency domains, and then a chaos optimization neural network is established for each domain. The forecasted so-lar irradiance is exactly the algebraic sum of all the forecasted components obtained by the re-spective networks, which correspond respec-tively the time-frequency domains. On the basis of combination of chaos optimization neural network and wavelet analysis, a model is devel-oped for more accurate forecasts of solar irradi-ance. An example of the forecast of daily solar irradiance is presented in the paper, the historical daily records of solar irradiance in Shanghai constituting the data sample. The results of the example show that the accuracy of the method is more展开更多
Enzymatic activities of beta-glucosidase (β-GLC), leucine-aminopeptidase (LAP), and alkaline phosphatase (APA), corresponding to nutrient eliminations, and the microbial community structures were analyzed in an anaer...Enzymatic activities of beta-glucosidase (β-GLC), leucine-aminopeptidase (LAP), and alkaline phosphatase (APA), corresponding to nutrient eliminations, and the microbial community structures were analyzed in an anaerobic-anoxic-aerobic reactor system. Results showed that most activity of β-GLC (64.2 μmol/(L·h)) associated with the largest fraction of small-molecular-weight carbohydrates was found in the aerobic reactor, indicating the existence of coupled hydrolysis-uptake mechanism in the aerobic bacteria. Similar activities of LAP presented in the anoxic and aerobic environments, whose increases accompanied by increments in nitrogen uptake rates greatly accelerated the processes of aerobic nitrification and anoxic denitrification. The highest APA activity displayed in the anaerobic reactor, however, dephosphorization performance was mainly achieved under aerobic condition. Microbial community fingerprints generated by polymerase chain reaction amplification and denaturing gradient gel electrophoresis (PCR-DGGE) revealed that Proteobacterium, Actinobacterium, and Nitrospira were the predominant classes in the activated sludge and there was no evidence of community variations among each function reactor in the system with biomass recycling.展开更多
基金This work was supported by foundation of National Key Fundamental Research and Development Program (2002CB412406)
文摘The spatial pattern of urbanization in the Shanghai metropolitan area is quantified with GIS-based land use data set and gradient analysis of landscape metrics. A number of landscape metrics were computed along a 64 km long and 6 km wide west-east transect and another 66 km long and 6 km wide south-north transect. The results of transect analysis with class-level metrics showed that the spatial pattern of urbanization could be reliably quantified using landscape metrics with a gradient analysis approach, and the location of the urbanization center could be identified precisely and consistently with multiple indices of the landscape metrics used in this study. Different land use types exhibited distinctive, but not necessarily unique,spatial signatures that were dependent on specific landscape metrics. These results seemed to characterize the urban core of the Shanghai metropolitan area rather accurately and precisely: Agriculture patches were abundant and less fragmented; the urban land use types were extensive,having many small patches and highly fragmented.
基金Supported by Nature Science Foundation of Heilongjiang Province ( No. E200510) and Education Affliction Program of HeilongjiangProvince (No.10551093)
文摘Mesocyclops Leukarti of zooplankton propagates excessively in eutrophic water body and it can not be effectively inactivated by the conventional process in drinking waterworks for its special surface structure. In this paper, a study of removal efficiency on Mesocyclops Leukarti with chlorine dioxide in a drinking waterworks was performed. Bench scale results showed that chlorine dioxide is more effective against Mesocyclops Leukarti. And Mesocyclops Leukarti could be effectively removed from water by 1.0 mg/L chlorine dioxide preoxidation cooperated with the conventional process during the full scale study. The chlorite, by-product of prechlorine dioxide, was constant at 0.45 mg/L after filtration, which was lower than the critical value of the USEPA. GC-MS examination and Ames test showed that the quantity of organics and the mutagenicity in the water treated by chlorine dioxide is obviously less than that of prechlorination.
文摘In this works, artificial neural network is com-bined with wavelet analysis for the forecast of solar irradiance. This method is characteristic of the preprocessing of sample data using wavelet transformation for the forecast, i.e., the data se-quence of solar irradiance as the sample is first mapped into several time-frequency domains, and then a chaos optimization neural network is established for each domain. The forecasted so-lar irradiance is exactly the algebraic sum of all the forecasted components obtained by the re-spective networks, which correspond respec-tively the time-frequency domains. On the basis of combination of chaos optimization neural network and wavelet analysis, a model is devel-oped for more accurate forecasts of solar irradi-ance. An example of the forecast of daily solar irradiance is presented in the paper, the historical daily records of solar irradiance in Shanghai constituting the data sample. The results of the example show that the accuracy of the method is more
文摘Enzymatic activities of beta-glucosidase (β-GLC), leucine-aminopeptidase (LAP), and alkaline phosphatase (APA), corresponding to nutrient eliminations, and the microbial community structures were analyzed in an anaerobic-anoxic-aerobic reactor system. Results showed that most activity of β-GLC (64.2 μmol/(L·h)) associated with the largest fraction of small-molecular-weight carbohydrates was found in the aerobic reactor, indicating the existence of coupled hydrolysis-uptake mechanism in the aerobic bacteria. Similar activities of LAP presented in the anoxic and aerobic environments, whose increases accompanied by increments in nitrogen uptake rates greatly accelerated the processes of aerobic nitrification and anoxic denitrification. The highest APA activity displayed in the anaerobic reactor, however, dephosphorization performance was mainly achieved under aerobic condition. Microbial community fingerprints generated by polymerase chain reaction amplification and denaturing gradient gel electrophoresis (PCR-DGGE) revealed that Proteobacterium, Actinobacterium, and Nitrospira were the predominant classes in the activated sludge and there was no evidence of community variations among each function reactor in the system with biomass recycling.