To evaluate the effect of tectonic deformation on coal reservoir properties, we provide an analysis of the types of tectonically deformed coal, macroand microscopic deformation and discuss pore structural characterist...To evaluate the effect of tectonic deformation on coal reservoir properties, we provide an analysis of the types of tectonically deformed coal, macroand microscopic deformation and discuss pore structural characteristics and connectivity based on samples from the Puhe and Shanchahe coal mines. Our research shows that the tectonically deformed coal mostly includes cataclastic structural coal, mortar structural coal and schistose structural coal of a brittle deformation series. The major pore structures of different types of tectonically deformed coal are transitional pores and micropores. The pore volumes of macropores and visible fracture pores produced by structural deformations vary over a large range and increase with the intensity of tectonic deformation. Mesopores as connecting passages develop well in schistose structural coal. According to the shapes of intrusive mercury curves, tectonically deformed coal can be divided into parallel, open and occluded types. The parallel type has poor connectivity and is relatively closed; the open type reflects uniformly developed open pores with good connectivity while the occluded type is good for coalbed methane enrichment, but has poor connectivity between pores.展开更多
The Shandong Xiajin Yellow River Ancient Mulberry Trees System is a model of desertification control in the floor area in the Luxibei Plain,and of sustainable development.The current study about ancient mulberry trees...The Shandong Xiajin Yellow River Ancient Mulberry Trees System is a model of desertification control in the floor area in the Luxibei Plain,and of sustainable development.The current study about ancient mulberry trees in Xiajin county is mainly qualitative representation,lack of quantitative research.In addition,the relevant important ecological functional assessment should not only confine to quantitative assessment which illustrate the current condition,but also analyze the eco-service changes,derived from ecosystem structure develop,from the time dimension.Based on quantitative eco-service assessment of the ancient mulberry tree group,this paper intend to conduct a comprehensive analysis of ecological functions of ancient mulberry group focuses on the perspective of system structure and function evolution.Quantitative evaluation results show that the system has significant eco-efficiency in water conservation,reducing sediment loss,adjust atmosphere,etc.On timescale,thanks to mulberry cultivation,ecosystem structure and services have also undergone a corresponding change.In ecosystem structure：Planting pioneer trees such as mulberries and other species which can tolerate hostile site conditions,improves the micro-environment.This makes it possible for other crops to grow.The mixed forests and the combination of forestry and agriculture protect biodiversity.What＇s more,they make the structure of the ecosystems more robust,giving full play to their functions.In terms of ecosystem services：ecosystem services of Xiajin Yellow River Ancient Mulberry Trees have shown diversified development.And its main function has transferred from supply products to leisure and entertainment functions.展开更多
Large-sczde structure of river flow is the main driving force for bed erosion-deposition and bank delbrmation. The structure shapes and retains a corresponding hydraulic geometry form. Therefore, the most stable flow ...Large-sczde structure of river flow is the main driving force for bed erosion-deposition and bank delbrmation. The structure shapes and retains a corresponding hydraulic geometry form. Therefore, the most stable flow structure is the probable natural river plane formation. Natural coordinate transformation and perturbation methods were adapted to deform the governing equations of sine-generated river basic flow and disturbance flow independently. The stability and retention of perturbation waves were analyzed in our model to explain why meandering rivers followed a certain type of tqow path. Computation results showed that all types of perturbation waves in meandering rivers were most stable when the meandering wave number was about 0.39-0.41. We believe that this type of stable flow structure shaped a certain meandering river. The statistical average length-width ratios of Yalin, Habib and da Silva and Leopold and Wolman somewhat confirmed our most stable river mean- dering wave number. In some ways, meandering rivers always tend to diminish internal turbulence intensity.展开更多
In a meandering fiver, a certain scale of turbulent vortex dominates the development of fiver morphology, making the river bend with s particular curvature. This kind of vortex is denoted as ＂bend-forming vortex＂. T...In a meandering fiver, a certain scale of turbulent vortex dominates the development of fiver morphology, making the river bend with s particular curvature. This kind of vortex is denoted as ＂bend-forming vortex＂. The coordinated relationship of bend-forming vortex and meandering fiver channel is then known as ＂self-adaption feature＂ of rivers. With these two concepts, this paper investigated the stability and self-adaption character of coherent vortex in the U-shape river bend with a constant curvature. On the basis of fluid mechanics theory and in consideration of turbulent coherent vortex as disturbance, the growth rate and the wave number response range of coherent vortex in meandering rivers with different curvatures were calculated in this paper. Moreover, the responses of different scales of coherent turbulence structure to river bend parameters were analyzed to explain the mechanism of fiver bend maintenance. These methods could provide a theoretical basis for further investigation on fiver meandering.展开更多
基金supported by the National Natural Science Foundation of China (No.40672101)the Key National Natural Science Foundation of China (No.40730422)+1 种基金the National Science and Technology Key Special Project from the Ministry of Technology of China (No. 2008ZX05034)the China Scholarship Council (CSC)
文摘To evaluate the effect of tectonic deformation on coal reservoir properties, we provide an analysis of the types of tectonically deformed coal, macroand microscopic deformation and discuss pore structural characteristics and connectivity based on samples from the Puhe and Shanchahe coal mines. Our research shows that the tectonically deformed coal mostly includes cataclastic structural coal, mortar structural coal and schistose structural coal of a brittle deformation series. The major pore structures of different types of tectonically deformed coal are transitional pores and micropores. The pore volumes of macropores and visible fracture pores produced by structural deformations vary over a large range and increase with the intensity of tectonic deformation. Mesopores as connecting passages develop well in schistose structural coal. According to the shapes of intrusive mercury curves, tectonically deformed coal can be divided into parallel, open and occluded types. The parallel type has poor connectivity and is relatively closed; the open type reflects uniformly developed open pores with good connectivity while the occluded type is good for coalbed methane enrichment, but has poor connectivity between pores.
基金The International Exchange and Cooperation Project of Ministry of Agriculture“Conservation of Globally Important Agricultural Heritage Systems(GIAHS)in China in 2016”The Youth Talent Supporting Project of China Association for Science and Technology(2016010103)
文摘The Shandong Xiajin Yellow River Ancient Mulberry Trees System is a model of desertification control in the floor area in the Luxibei Plain,and of sustainable development.The current study about ancient mulberry trees in Xiajin county is mainly qualitative representation,lack of quantitative research.In addition,the relevant important ecological functional assessment should not only confine to quantitative assessment which illustrate the current condition,but also analyze the eco-service changes,derived from ecosystem structure develop,from the time dimension.Based on quantitative eco-service assessment of the ancient mulberry tree group,this paper intend to conduct a comprehensive analysis of ecological functions of ancient mulberry group focuses on the perspective of system structure and function evolution.Quantitative evaluation results show that the system has significant eco-efficiency in water conservation,reducing sediment loss,adjust atmosphere,etc.On timescale,thanks to mulberry cultivation,ecosystem structure and services have also undergone a corresponding change.In ecosystem structure：Planting pioneer trees such as mulberries and other species which can tolerate hostile site conditions,improves the micro-environment.This makes it possible for other crops to grow.The mixed forests and the combination of forestry and agriculture protect biodiversity.What＇s more,they make the structure of the ecosystems more robust,giving full play to their functions.In terms of ecosystem services：ecosystem services of Xiajin Yellow River Ancient Mulberry Trees have shown diversified development.And its main function has transferred from supply products to leisure and entertainment functions.
基金supported by the National Natural Science Foundation of China(Grant Nos.51279124,50979066,51009105)the Natural Science Foundation of Tianjin(Grant No.12JCQNJC05600)
文摘Large-sczde structure of river flow is the main driving force for bed erosion-deposition and bank delbrmation. The structure shapes and retains a corresponding hydraulic geometry form. Therefore, the most stable flow structure is the probable natural river plane formation. Natural coordinate transformation and perturbation methods were adapted to deform the governing equations of sine-generated river basic flow and disturbance flow independently. The stability and retention of perturbation waves were analyzed in our model to explain why meandering rivers followed a certain type of tqow path. Computation results showed that all types of perturbation waves in meandering rivers were most stable when the meandering wave number was about 0.39-0.41. We believe that this type of stable flow structure shaped a certain meandering river. The statistical average length-width ratios of Yalin, Habib and da Silva and Leopold and Wolman somewhat confirmed our most stable river mean- dering wave number. In some ways, meandering rivers always tend to diminish internal turbulence intensity.
基金supported by the National Natural Science Foundation for Innovative Research Groups of China (Grant No.51021004)the National Natural Science Foundation of China (Grant Nos.50979066,50809045)
文摘In a meandering fiver, a certain scale of turbulent vortex dominates the development of fiver morphology, making the river bend with s particular curvature. This kind of vortex is denoted as ＂bend-forming vortex＂. The coordinated relationship of bend-forming vortex and meandering fiver channel is then known as ＂self-adaption feature＂ of rivers. With these two concepts, this paper investigated the stability and self-adaption character of coherent vortex in the U-shape river bend with a constant curvature. On the basis of fluid mechanics theory and in consideration of turbulent coherent vortex as disturbance, the growth rate and the wave number response range of coherent vortex in meandering rivers with different curvatures were calculated in this paper. Moreover, the responses of different scales of coherent turbulence structure to river bend parameters were analyzed to explain the mechanism of fiver bend maintenance. These methods could provide a theoretical basis for further investigation on fiver meandering.
