Based on the observed data in monitored drainage areas and GIS spatial analysis tools,watershed basic database of Shitoukoumen Reservoir Basin was built.The multivariate analysis and redundancy analysis(RDA) were used...Based on the observed data in monitored drainage areas and GIS spatial analysis tools,watershed basic database of Shitoukoumen Reservoir Basin was built.The multivariate analysis and redundancy analysis(RDA) were used to analyze the spatial and temporal variations of water quality,identify the key environmental factors and their patterns influencing the spatial variation of water quality,and determine the main types and forms of the non-point source(NPS) pollutant export controlled by the key environmental factors.The results show that different patterns of environmental factors lead to great changes in water quality at spatial and seasonal scales.All selected environmental factors explain 64.5% and 68.2% of the spatial variation of water quality over dry season and rainy season,respectively,which shows clear seasonal difference.Over dry season,residential land is the most important environmental factor,which possesses 35.4% of the spatial variation,and drainage area is the second key environmental factor,which possesses 17.0% of spatial variation in the total variance.Over rainy season,slope length and drainage area are the key environmental factors,which possess 29.3% of the spatial variation together.Residential land influences nitrogen export by changing NH4+-N and particulate organic nitrogen(PON) discharge over dry season,and drainage area controls phosphorus export by regulating dissolved phosphorus(DP) drainage over dry season and phosphorus associated particulate(PAP) loss over rainy season,respectively.Although slope length is an important environmental factor,it does not influence NPS pollutant export.It is interesting that soil organic matter,as a minor environmental factor,highly determines phosphorus and nitrogen export by enhancing the DP,PAP and PON loss.展开更多
Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation.During these processes,typically,a large amount of working fluid enters t...Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation.During these processes,typically,a large amount of working fluid enters the formation,resulting in widespread water-rock interaction.Deeply understanding such effects is required to optimize the production system.In this study,the mechanisms of water-rock interaction and the associated responses of shale fabric are systematically reviewed for working fluids such as neutral fluids,acid fluids,alkali fluids and oxidative fluids.It is shown that shale is generally rich in water-sensitive components such as clay minerals,acidsensitive components(like carbonate minerals),alkali-sensitive components(like quartz),oxidative-sensitive components(like organic matter and pyrite),which easily lead to change of rock fabric and mechanical properties owing to water-rock interaction.According to the results,oxidizing acid fluids and oxidizing fracturing fluids should be used to enhance shale gas recovery.This study also indicates that an aspect playing an important role in increasing cumulative gas production is the optimization of the maximum shut-in time based on the change point of the wellhead pressure drop rate.Another important influential factor to be considered is the control of the wellhead pressure considering the stress sensitivity and creep characteristics of the fracture network.展开更多
To study the occurrence mechanism of rock burst during mining the irregular working face,the study took irregular panel 7447 near fault tectonic as an engineering background.The spatial fracture characteristic of over...To study the occurrence mechanism of rock burst during mining the irregular working face,the study took irregular panel 7447 near fault tectonic as an engineering background.The spatial fracture characteristic of overlying strata was analyzed by Winkler elastic foundation beam theory.Furthermore,the influence law of panel width to suspended width and limit breaking span of key strata were also analyzed by thin plate theory.Through micro-seismic monitoring,theoretical analysis,numerical simulation and working resistance of support of field measurement,this study investigated the fracture characteristic of overlying strata and mechanism of rock burst in irregular working face.The results show that the fracture characteristic of overlying strata shows a spatial trapezoid structure,with the main roof being as an undersurface.The fracture form changes from vertical‘‘O-X"type to transverse‘‘O-X"type with the increase of trapezoidal height.From the narrow mining face to the wide mining face,the suspended width of key strata is greater than its limit breaking width,and a strong dynamic load is produced by the fracture of key strata.The numerical simulation and micro-seismic monitoring results show that the initial fracture position of key strata is close to tailgate 7447.Also there is a high static load caused by fault tectonic.The dynamic and static combined load induce rock burst.Accordingly,a cooperative control technology was proposed,which can weaken dynamic load by hard roof directional hydraulic fracture and enhance surrounding rock by supporting system.展开更多
In the government work report for Two Sessions 2019, key words about E-commerce and internet were mentioned lots of times. This included terms such as Internet+, cross-border E-commerce,industrial internet, digital ec...In the government work report for Two Sessions 2019, key words about E-commerce and internet were mentioned lots of times. This included terms such as Internet+, cross-border E-commerce,industrial internet, digital economy,sharing economy, online and offline consumption, Internet+education and soon.Keywords No.1:Internet+Work Report:1. Internet+was advanced across the board and new technologies and models were used to transform traditional industries. 2. We will speed up efforts to pursue Internet+in all industries and sectors.展开更多
In the process of piano teaching,it is the basic working ability of piano teachers to independently study and process works and guide students.In the face of a strange work,the piano teacher should first conduct a com...In the process of piano teaching,it is the basic working ability of piano teachers to independently study and process works and guide students.In the face of a strange work,the piano teacher should first conduct a comprehensive analysis and research of the work,and then can reasonably guide the students.Starting from three aspects of work research,performance design,and key points of attention,this paper expounds the ways and steps of work research and processing in order to help the piano teachers to expand their teaching repertoire.展开更多
By employing network-based observation techniques, field experimental methods and ecological information technology, the Lab is designed to explore the coupling between carbon, water and nutrient cycles within an ecos...By employing network-based observation techniques, field experimental methods and ecological information technology, the Lab is designed to explore the coupling between carbon, water and nutrient cycles within an ecosystem and its underlying mechanisms, to integrate and model ecosystem patterns and processes at multiple spatiotemporal scales, and to comprehensively study the relationship between ecosystem management and sustainable development. Its major focuses are：展开更多
基金Under the auspices of Cooperation Program of Chinese Academy of Sciences and Jilin Province (No 2006SYHZ0025)Knowledge Innovation Programs of Chinese Academy of Sciences (No KZCX2-YW-126,KZCX2-YW-Q06-2)
文摘Based on the observed data in monitored drainage areas and GIS spatial analysis tools,watershed basic database of Shitoukoumen Reservoir Basin was built.The multivariate analysis and redundancy analysis(RDA) were used to analyze the spatial and temporal variations of water quality,identify the key environmental factors and their patterns influencing the spatial variation of water quality,and determine the main types and forms of the non-point source(NPS) pollutant export controlled by the key environmental factors.The results show that different patterns of environmental factors lead to great changes in water quality at spatial and seasonal scales.All selected environmental factors explain 64.5% and 68.2% of the spatial variation of water quality over dry season and rainy season,respectively,which shows clear seasonal difference.Over dry season,residential land is the most important environmental factor,which possesses 35.4% of the spatial variation,and drainage area is the second key environmental factor,which possesses 17.0% of spatial variation in the total variance.Over rainy season,slope length and drainage area are the key environmental factors,which possess 29.3% of the spatial variation together.Residential land influences nitrogen export by changing NH4+-N and particulate organic nitrogen(PON) discharge over dry season,and drainage area controls phosphorus export by regulating dissolved phosphorus(DP) drainage over dry season and phosphorus associated particulate(PAP) loss over rainy season,respectively.Although slope length is an important environmental factor,it does not influence NPS pollutant export.It is interesting that soil organic matter,as a minor environmental factor,highly determines phosphorus and nitrogen export by enhancing the DP,PAP and PON loss.
基金Lijun,You,Innovative Research Project for Sichuan Youth Scientific and Technological Innovation(Grants No.2016TD0016)Qiuyang Cheng,Postdoctoral Research Project of Petrochina Southwest Oil and Gas Field Company(Grants No.20230304-13).
文摘Horizontal well drilling and multi-stage hydraulic fracturing technologies are at the root of commercial shale gas development and exploitation.During these processes,typically,a large amount of working fluid enters the formation,resulting in widespread water-rock interaction.Deeply understanding such effects is required to optimize the production system.In this study,the mechanisms of water-rock interaction and the associated responses of shale fabric are systematically reviewed for working fluids such as neutral fluids,acid fluids,alkali fluids and oxidative fluids.It is shown that shale is generally rich in water-sensitive components such as clay minerals,acidsensitive components(like carbonate minerals),alkali-sensitive components(like quartz),oxidative-sensitive components(like organic matter and pyrite),which easily lead to change of rock fabric and mechanical properties owing to water-rock interaction.According to the results,oxidizing acid fluids and oxidizing fracturing fluids should be used to enhance shale gas recovery.This study also indicates that an aspect playing an important role in increasing cumulative gas production is the optimization of the maximum shut-in time based on the change point of the wellhead pressure drop rate.Another important influential factor to be considered is the control of the wellhead pressure considering the stress sensitivity and creep characteristics of the fracture network.
基金supported by the Key Project of National Natural Science Foundation of China (No. 51634001)the National Natural Science Foundation of China (Nos. 51404269 and 51674253)+1 种基金the State Key Research Development Program of China (No. 2016YFC0801403)the Key Research Development Program of Jiangsu Province, China (No. BE2015040)
文摘To study the occurrence mechanism of rock burst during mining the irregular working face,the study took irregular panel 7447 near fault tectonic as an engineering background.The spatial fracture characteristic of overlying strata was analyzed by Winkler elastic foundation beam theory.Furthermore,the influence law of panel width to suspended width and limit breaking span of key strata were also analyzed by thin plate theory.Through micro-seismic monitoring,theoretical analysis,numerical simulation and working resistance of support of field measurement,this study investigated the fracture characteristic of overlying strata and mechanism of rock burst in irregular working face.The results show that the fracture characteristic of overlying strata shows a spatial trapezoid structure,with the main roof being as an undersurface.The fracture form changes from vertical‘‘O-X"type to transverse‘‘O-X"type with the increase of trapezoidal height.From the narrow mining face to the wide mining face,the suspended width of key strata is greater than its limit breaking width,and a strong dynamic load is produced by the fracture of key strata.The numerical simulation and micro-seismic monitoring results show that the initial fracture position of key strata is close to tailgate 7447.Also there is a high static load caused by fault tectonic.The dynamic and static combined load induce rock burst.Accordingly,a cooperative control technology was proposed,which can weaken dynamic load by hard roof directional hydraulic fracture and enhance surrounding rock by supporting system.
文摘In the government work report for Two Sessions 2019, key words about E-commerce and internet were mentioned lots of times. This included terms such as Internet+, cross-border E-commerce,industrial internet, digital economy,sharing economy, online and offline consumption, Internet+education and soon.Keywords No.1:Internet+Work Report:1. Internet+was advanced across the board and new technologies and models were used to transform traditional industries. 2. We will speed up efforts to pursue Internet+in all industries and sectors.
基金one of the phased achievements of the teaching reform project of Sichuan Minzu College,the notice of the Academic Affairs Office of Sichuan University for Nationalities on strengthening the construction of the second batch of application-oriented demonstration majors and the first batch of application-oriented Demonstration Courses of local ordinary undergraduate universities in Sichuan Province.Document No.[2019]11 issued by Sichuan Minzu College.
文摘In the process of piano teaching,it is the basic working ability of piano teachers to independently study and process works and guide students.In the face of a strange work,the piano teacher should first conduct a comprehensive analysis and research of the work,and then can reasonably guide the students.Starting from three aspects of work research,performance design,and key points of attention,this paper expounds the ways and steps of work research and processing in order to help the piano teachers to expand their teaching repertoire.
文摘By employing network-based observation techniques, field experimental methods and ecological information technology, the Lab is designed to explore the coupling between carbon, water and nutrient cycles within an ecosystem and its underlying mechanisms, to integrate and model ecosystem patterns and processes at multiple spatiotemporal scales, and to comprehensively study the relationship between ecosystem management and sustainable development. Its major focuses are：
