After the normal operation of the Three Gorges Reservoir,the water level of the reser-voir will fluctuate periodically.Water level fluctuation will soften the rock and soil on the banks,induce underground water fluctu...After the normal operation of the Three Gorges Reservoir,the water level of the reser-voir will fluctuate periodically.Water level fluctuation will soften the rock and soil on the banks,induce underground water fluctuation and decrease the shear strength of rock soil on the banks,and in turn affect the landslide stability.The Huangtupo（黄土坡） landslide is a typical large and complex landslide in the Three Gorges Reservoir region.In particular,the stability of its riverside slumping mass has a great stake.On the basis of the analysis of engineering geological condition and formation mechanism of the Huangtupo landslide,the authors established the 2D finite element model of riverside slumping mass II# and selected proper mechanical parameters of the rock.With the GeoStudio software,ac-cording to the reservoir running curve,the simulation on coupling effect of seepage field and stress field was conducted in 7 different modes in a year.The results showed that：① Huangtupo landslide is a large and complex landslide composed of multiple slumping masses,which occurred at different phases.Before reservoir impoundment,it was stable;② it is quite difficult for riverside slumping mass I# and II# to slide as a whole;③ the stability coefficient of riverside slumping mass II# changes with the res-ervoir water level fluctuations.The minimum stability coefficient occurs 48 days after the water level starts to fall and the moment when the water level falls by 11.9 m.Landslide monitoring result is con-sistent with the numerical simulation result,which shows that although the reservoir water level fluc-tuation will affect the foreside stability of the landslide and induce gradual damage,the riverside slumping mass II# is stable as a whole.展开更多
Two representative zones in Chongming Dongtan which faced the Yangtze River and East China Sea respectively were selected to study the variability of soil organic carbon （SOC） reservation capability between coastal ...Two representative zones in Chongming Dongtan which faced the Yangtze River and East China Sea respectively were selected to study the variability of soil organic carbon （SOC） reservation capability between coastal wetland and riverside wetland in the Chongming Dongtan wetland as well as its mechanism by analyzing soil characteristics and plant biomass.The results showed the SOC content of riverside wetland was only 48.61% （P=0.000 〈 0.05） that of coastal wetland.As the organic matter inputs from plant litter of the coastal wetland and riverside wetland were approximately the same,the higher soil microbial respiration （SMR） of riverside wetland led to its lower SOC reservation capability.In the riverside wetland,the high soil microbial biomass,higher proportion of β-Proteobacteria,which have strong carbon metabolism activity and the existence of some specific aerobic heterotrophic bacteria such as Bacilli and uncultured Lactococcus,were the important reasons for the higher SMR compared to the coastal wetland.There were additional differences in soil physical and chemical characteristics between the coastal wetland and riverside wetlands.Path analysis of predominant bacteria and microbial biomass showed that soil salinity influenced β-Proteobacteria and microbial biomass most negatively among these physical and chemical factors.Therefore the low salinity of the riverside area was suitable for the growth of microorganisms,especially β-Proteobacteria and some specific bacteria,which led to the high SMR and low SOC reservation capability when compared to the coastal area.展开更多
Continuous landscape components along the lateral riverside are affected by both hydrologic connectivity and disconnectivity.In recent years,anthropogenic activities and climate changes have caused wetland shrinkage a...Continuous landscape components along the lateral riverside are affected by both hydrologic connectivity and disconnectivity.In recent years,anthropogenic activities and climate changes have caused wetland shrinkage and land degradation along the lateral riverside of many arid and semiarid regions.Since microorganisms are major drivers of soil biochemical cycling,it is essential to examine soil microbial communities along the lateral landscape continuum to understand their ecosystem functioning and predict future land changes.Here,we collected samples along a lateral riverbed center-riverbed edge-oxbow lake-floodplain-terrace continuum(i.e.,landward distribution)in the Xilin River Basin,Inner Mongolia,China.The floodplain had the highest microbial diversity and heterogeneity,with Bacteroidetes,β-andγ-Proteobacteria being the most abundant taxa.In contrast,the terrace had the lowest microbial diversity and heterogeneity,with Acidobacteria,Actinobacteria,Verrucomicrobia,Gemmatimonadetes,andα-Proteobacteria as the most abundant taxa.Silt particle,salinity,and moisture were the most influential factors for landward variation of bacterial communities along the riverside continuum.Altogether,we demonstrate that dominant bacterial lineages,soil particles,and moisture-related factors are valuable indicators of this continuum,which can be leveraged for the early prediction of drought-induced wetland shrinkage and grassland desertification.展开更多
With an analysis on the city image presented by the painting of Riverside Scene at Qingming Festival, as well as other relevant documents, this paper explores the factors that caused the market system reform in the No...With an analysis on the city image presented by the painting of Riverside Scene at Qingming Festival, as well as other relevant documents, this paper explores the factors that caused the market system reform in the Northern Song Dynasty. It also explores the features of Dongjing, the capital city's commercial space prompted by the reform, revealing that the growth of urban population, the rise of its commercial status and the emergence of citizen class were the essential factors contributing to the market system reform. It concludes that Dongjing's commercial space shows the following characteristics: developing in a linear form, gradually forming a commercial network system by integrating various shops, markets, and warehouses, expanding to the Outer City to combine the prosperous grassroots markets, and hosting commercial activities with longer business time.展开更多
基金supported by the National Natural Science Fundation of China (No. 40872175)the National Basic Research Program of China (973 Program) (No. 2011CB710604)
文摘After the normal operation of the Three Gorges Reservoir,the water level of the reser-voir will fluctuate periodically.Water level fluctuation will soften the rock and soil on the banks,induce underground water fluctuation and decrease the shear strength of rock soil on the banks,and in turn affect the landslide stability.The Huangtupo（黄土坡） landslide is a typical large and complex landslide in the Three Gorges Reservoir region.In particular,the stability of its riverside slumping mass has a great stake.On the basis of the analysis of engineering geological condition and formation mechanism of the Huangtupo landslide,the authors established the 2D finite element model of riverside slumping mass II# and selected proper mechanical parameters of the rock.With the GeoStudio software,ac-cording to the reservoir running curve,the simulation on coupling effect of seepage field and stress field was conducted in 7 different modes in a year.The results showed that：① Huangtupo landslide is a large and complex landslide composed of multiple slumping masses,which occurred at different phases.Before reservoir impoundment,it was stable;② it is quite difficult for riverside slumping mass I# and II# to slide as a whole;③ the stability coefficient of riverside slumping mass II# changes with the res-ervoir water level fluctuations.The minimum stability coefficient occurs 48 days after the water level starts to fall and the moment when the water level falls by 11.9 m.Landslide monitoring result is con-sistent with the numerical simulation result,which shows that although the reservoir water level fluc-tuation will affect the foreside stability of the landslide and induce gradual damage,the riverside slumping mass II# is stable as a whole.
基金supported by the National Major Scientific and Technological Project of China (No.2010BAK69B13,2010BAK69B14)the Major Project of the Shanghai Scientific and Technological Committee(No. 10dz1200903,10dz1200700)
文摘Two representative zones in Chongming Dongtan which faced the Yangtze River and East China Sea respectively were selected to study the variability of soil organic carbon （SOC） reservation capability between coastal wetland and riverside wetland in the Chongming Dongtan wetland as well as its mechanism by analyzing soil characteristics and plant biomass.The results showed the SOC content of riverside wetland was only 48.61% （P=0.000 〈 0.05） that of coastal wetland.As the organic matter inputs from plant litter of the coastal wetland and riverside wetland were approximately the same,the higher soil microbial respiration （SMR） of riverside wetland led to its lower SOC reservation capability.In the riverside wetland,the high soil microbial biomass,higher proportion of β-Proteobacteria,which have strong carbon metabolism activity and the existence of some specific aerobic heterotrophic bacteria such as Bacilli and uncultured Lactococcus,were the important reasons for the higher SMR compared to the coastal wetland.There were additional differences in soil physical and chemical characteristics between the coastal wetland and riverside wetlands.Path analysis of predominant bacteria and microbial biomass showed that soil salinity influenced β-Proteobacteria and microbial biomass most negatively among these physical and chemical factors.Therefore the low salinity of the riverside area was suitable for the growth of microorganisms,especially β-Proteobacteria and some specific bacteria,which led to the high SMR and low SOC reservation capability when compared to the coastal area.
基金the National Natural Science Foundation of China to J.Yu(41361053),X.Tanggood(31660724)and Y.Yang(41825016)the Natural Science Foundation of Inner Mongolia to J.Yu(2011MS0603,2016MS0331)and X.Tanggood(2015MS0306)the National College Students Innovation and Entrepreneurship Training Program of Inner Mongolia University to C.H.Li,X.Li,W.Z.Wu,W.Dong and Y.Jia(201810126043).
文摘Continuous landscape components along the lateral riverside are affected by both hydrologic connectivity and disconnectivity.In recent years,anthropogenic activities and climate changes have caused wetland shrinkage and land degradation along the lateral riverside of many arid and semiarid regions.Since microorganisms are major drivers of soil biochemical cycling,it is essential to examine soil microbial communities along the lateral landscape continuum to understand their ecosystem functioning and predict future land changes.Here,we collected samples along a lateral riverbed center-riverbed edge-oxbow lake-floodplain-terrace continuum(i.e.,landward distribution)in the Xilin River Basin,Inner Mongolia,China.The floodplain had the highest microbial diversity and heterogeneity,with Bacteroidetes,β-andγ-Proteobacteria being the most abundant taxa.In contrast,the terrace had the lowest microbial diversity and heterogeneity,with Acidobacteria,Actinobacteria,Verrucomicrobia,Gemmatimonadetes,andα-Proteobacteria as the most abundant taxa.Silt particle,salinity,and moisture were the most influential factors for landward variation of bacterial communities along the riverside continuum.Altogether,we demonstrate that dominant bacterial lineages,soil particles,and moisture-related factors are valuable indicators of this continuum,which can be leveraged for the early prediction of drought-induced wetland shrinkage and grassland desertification.
文摘With an analysis on the city image presented by the painting of Riverside Scene at Qingming Festival, as well as other relevant documents, this paper explores the factors that caused the market system reform in the Northern Song Dynasty. It also explores the features of Dongjing, the capital city's commercial space prompted by the reform, revealing that the growth of urban population, the rise of its commercial status and the emergence of citizen class were the essential factors contributing to the market system reform. It concludes that Dongjing's commercial space shows the following characteristics: developing in a linear form, gradually forming a commercial network system by integrating various shops, markets, and warehouses, expanding to the Outer City to combine the prosperous grassroots markets, and hosting commercial activities with longer business time.
