Population distribution and their temporal variation are a direct proxy of urbanization. This study evaluates the population density variation of China between 2000 and 2010 at the township level by using the data of ...Population distribution and their temporal variation are a direct proxy of urbanization. This study evaluates the population density variation of China between 2000 and 2010 at the township level by using the data of the fi fth and sixth national population censuses. The urbanization patterns of China in 2000 and 2010 are depicted based on the population densities at various levels and the urbanization process of China between 2000 and 2010 is then analyzed through a comparative approach. It also tries to visualize the population density dynamics and urbanization pattern variations of China at the township level.展开更多
Soil samples were collected from the areas surrounding Wuliangsuhai Lake in China. Dissolved organic matter (DOM) was extracted from the samples and characterized by fluorescence and UV-Vis spectra. Spectral propert...Soil samples were collected from the areas surrounding Wuliangsuhai Lake in China. Dissolved organic matter (DOM) was extracted from the samples and characterized by fluorescence and UV-Vis spectra. Spectral properties and humification degree of DOM were studied. The results indicated that both humic- and protein- like fluorophores were present in the DOM spectra, and the former was the dominant component. The analysis of humification (HIX) and r (A, C) indices revealed that the maximum humification degree in three agricultural soils (AAF, ASC, and ASW) was presented in the second soil layer (20-40 cm). However, the humification degree of the two Halophytes soils (SSE and GKF) decreased with increasing depth. One index, I344/270, showed that humification degree increased gradually with an increasing proportion of humic-like acid. There was a significant positive correlation between humification degree (HIX) and aromaticity (SUVA254), indicating that a higher aromaticity corresponded to a higher humification degree. Land use was an important factor responsible for the major difference of cation exchange capacity (CEC) in different soils, which led to a higher CEC value in the second soil layer for the three agricultural soils. CEC values and humification degree had the same trend for all five soils. The correlation analysis showed that there was a significant positive correlation between HIX and CEC,and a negative correlation between the r (A, C) index and CEC, indicating that humification degree increases gradually with increasing CEC values.展开更多
Bulk coal combustion in rural households is a major contributor to PM_(2.5)pollution in Northern China[1,2].To promote the energy transition and reduce bulk coal combustion for heating in rural areas,China initiated t...Bulk coal combustion in rural households is a major contributor to PM_(2.5)pollution in Northern China[1,2].To promote the energy transition and reduce bulk coal combustion for heating in rural areas,China initiated the Winter Clean Heating Action Plan in Rural Northern China in 2017,hereinafter referred to as rural clean heating(RCH)[3].The 2+26 region,comprising Beijing,Tianjin,and 26 other municipalities in the surrounding area(Fig.S1 online),is the key implementation area for the RCH.展开更多
文摘Population distribution and their temporal variation are a direct proxy of urbanization. This study evaluates the population density variation of China between 2000 and 2010 at the township level by using the data of the fi fth and sixth national population censuses. The urbanization patterns of China in 2000 and 2010 are depicted based on the population densities at various levels and the urbanization process of China between 2000 and 2010 is then analyzed through a comparative approach. It also tries to visualize the population density dynamics and urbanization pattern variations of China at the township level.
基金Acknowledgements This work was financially supported by the National Social Science Fund (12CGLI 18), the National Natural Science Foundation of China (Grant Nos. 41503110 and 51208020) and the Open Foundation of Jiangsu Key Laboratory for Biomass-based Energy and Enzyme Technology, Huaiyin Normal University (JSBEET1309).
文摘Soil samples were collected from the areas surrounding Wuliangsuhai Lake in China. Dissolved organic matter (DOM) was extracted from the samples and characterized by fluorescence and UV-Vis spectra. Spectral properties and humification degree of DOM were studied. The results indicated that both humic- and protein- like fluorophores were present in the DOM spectra, and the former was the dominant component. The analysis of humification (HIX) and r (A, C) indices revealed that the maximum humification degree in three agricultural soils (AAF, ASC, and ASW) was presented in the second soil layer (20-40 cm). However, the humification degree of the two Halophytes soils (SSE and GKF) decreased with increasing depth. One index, I344/270, showed that humification degree increased gradually with an increasing proportion of humic-like acid. There was a significant positive correlation between humification degree (HIX) and aromaticity (SUVA254), indicating that a higher aromaticity corresponded to a higher humification degree. Land use was an important factor responsible for the major difference of cation exchange capacity (CEC) in different soils, which led to a higher CEC value in the second soil layer for the three agricultural soils. CEC values and humification degree had the same trend for all five soils. The correlation analysis showed that there was a significant positive correlation between HIX and CEC,and a negative correlation between the r (A, C) index and CEC, indicating that humification degree increases gradually with increasing CEC values.
基金supported by the National Natural Science Foundation of China(72074155,72074137,72374107)the Shandong Province Natural Science Foundation(ZR2021YQ27)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20230062)the National Key R&D Program of China(2022YFF0802504)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX22_1223)。
文摘Bulk coal combustion in rural households is a major contributor to PM_(2.5)pollution in Northern China[1,2].To promote the energy transition and reduce bulk coal combustion for heating in rural areas,China initiated the Winter Clean Heating Action Plan in Rural Northern China in 2017,hereinafter referred to as rural clean heating(RCH)[3].The 2+26 region,comprising Beijing,Tianjin,and 26 other municipalities in the surrounding area(Fig.S1 online),is the key implementation area for the RCH.