Dianchi Lake is one of the lakes with the richest phosphorus source in the world, in which the P2O5 content in the bottom sediments reaches averagely 0.51 wt % and maximally 1.92%. Studies indicate that this: extremel...Dianchi Lake is one of the lakes with the richest phosphorus source in the world, in which the P2O5 content in the bottom sediments reaches averagely 0.51 wt % and maximally 1.92%. Studies indicate that this: extremely P-rich state is attributed mainly to the large volume (as high as hundred thousands of tons) of phosphatic matter coming into the lake as many rivers feeding the lake pass through a vast area of phosphate-mining districts, which then undergo weathering and particularly some human activities, including waste water discharge. When phosphatic matter enters the lake, its grained parts are firstly decomposed by phosphorus-decomposing bacteria, and finally accumulated in some geographically special parts of the lake, such as a bay area where water flow is much more slower than elsewhere in the lake. With the involvement of phosphorus-concentrating bacteria, the accumulated phosphates in the bottom sludge ultimately form phosphate minerals through deep-burial diagenesis.展开更多
Study on the carbonate content and oxygen isotope of a sediment section in Dabusu Lake revealed that this region has experienced several cold wet and warm dry climatic cycles since 15400 a BP. It was about 6740 a BP w...Study on the carbonate content and oxygen isotope of a sediment section in Dabusu Lake revealed that this region has experienced several cold wet and warm dry climatic cycles since 15400 a BP. It was about 6740 a BP when the climate in the region reached a relatively stable warm stage, so that the lake water was gradually condensed and finally a saline lake was formed.展开更多
With the passing of Jürgen Remane, the geological institute in the University of Neuchǎtel and geoscience in general, lost a scientist of international reputation, a gifted teacher, and—above all—a good friend.
In a shale gas and oil reservoir,hydrocarbon fluids are stored in organic nanopores with sizes on the order of~1-100 nm.The adsorption,selectivity,and phase behavior of hydrocarbons in the nanopores are crucial for es...In a shale gas and oil reservoir,hydrocarbon fluids are stored in organic nanopores with sizes on the order of~1-100 nm.The adsorption,selectivity,and phase behavior of hydrocarbons in the nanopores are crucial for estimating the gas-in-place and predicting the productivity.In this study,to understand the characteristics of the phase behavior of multicomponent hydrocarbon systems in shale reservoirs,the phase behavior of a CH_(4)/n-C_(4)H_(10)binary mixture in graphite nanopores was investigated by Grand Ca-nonical Monte Carlo(GCMC)molecular simulation.The method for determining the dew-point pressure and bubble-point pressure in the nanopores was explored.The condensation phenomenon was observed owing to the difference in the adsorption selectivities of the hydrocarbon molecules on the nanopore surfaces,and hence the dew-point pressure(and bubble-point pressure)of hydrocarbon mixtures in the nanopores significantly shifted.The GCMC simulations reproduced both the higher and lower bubble-point pressures in nanopores in previous studies.This work highlights the crucial role of the selec-tivity in the phase behavior of hydrocarbons in nanopores.展开更多
基金The present study is part of the results of a project(No.4987204)granted by the National Natural Science Foundation of China.
文摘Dianchi Lake is one of the lakes with the richest phosphorus source in the world, in which the P2O5 content in the bottom sediments reaches averagely 0.51 wt % and maximally 1.92%. Studies indicate that this: extremely P-rich state is attributed mainly to the large volume (as high as hundred thousands of tons) of phosphatic matter coming into the lake as many rivers feeding the lake pass through a vast area of phosphate-mining districts, which then undergo weathering and particularly some human activities, including waste water discharge. When phosphatic matter enters the lake, its grained parts are firstly decomposed by phosphorus-decomposing bacteria, and finally accumulated in some geographically special parts of the lake, such as a bay area where water flow is much more slower than elsewhere in the lake. With the involvement of phosphorus-concentrating bacteria, the accumulated phosphates in the bottom sludge ultimately form phosphate minerals through deep-burial diagenesis.
文摘Study on the carbonate content and oxygen isotope of a sediment section in Dabusu Lake revealed that this region has experienced several cold wet and warm dry climatic cycles since 15400 a BP. It was about 6740 a BP when the climate in the region reached a relatively stable warm stage, so that the lake water was gradually condensed and finally a saline lake was formed.
文摘With the passing of Jürgen Remane, the geological institute in the University of Neuchǎtel and geoscience in general, lost a scientist of international reputation, a gifted teacher, and—above all—a good friend.
基金the Promotion of Science(JSPS)for a Grant-in-Aid for Scientific Research A(No.24246148)a Grant-in-Aid for Scientific Research C(No.17K06988).
文摘In a shale gas and oil reservoir,hydrocarbon fluids are stored in organic nanopores with sizes on the order of~1-100 nm.The adsorption,selectivity,and phase behavior of hydrocarbons in the nanopores are crucial for estimating the gas-in-place and predicting the productivity.In this study,to understand the characteristics of the phase behavior of multicomponent hydrocarbon systems in shale reservoirs,the phase behavior of a CH_(4)/n-C_(4)H_(10)binary mixture in graphite nanopores was investigated by Grand Ca-nonical Monte Carlo(GCMC)molecular simulation.The method for determining the dew-point pressure and bubble-point pressure in the nanopores was explored.The condensation phenomenon was observed owing to the difference in the adsorption selectivities of the hydrocarbon molecules on the nanopore surfaces,and hence the dew-point pressure(and bubble-point pressure)of hydrocarbon mixtures in the nanopores significantly shifted.The GCMC simulations reproduced both the higher and lower bubble-point pressures in nanopores in previous studies.This work highlights the crucial role of the selec-tivity in the phase behavior of hydrocarbons in nanopores.
