[Objective] To investigate the appropriate low-carbon agriculture model in Southern Jiangsu Province. [Method] Through the analysis of regional features in Southern Jiangsu and several matured low-carbon agriculture d...[Objective] To investigate the appropriate low-carbon agriculture model in Southern Jiangsu Province. [Method] Through the analysis of regional features in Southern Jiangsu and several matured low-carbon agriculture development models at present, the low-carbon agriculture development modes suitable for Southern Jiangsu were investigated, and corresponding supporting measures for the development of the models were put forward. [Result] Low-carbon agriculture is the environment- friendly agriculture which achieves low emissions, low pollution, high efficiency and high-yield through efficient recycling of energy and resources and continuous im- provements on ecological environment. With a variety of development models, the specific development model for practical use should be determined according to the local conditions, and supported by corresponding supporting measures, to achieve the rapid development of low-carbon agriculture. [Conclusion] This study laid the foundation for the development of low-carbon agriculture model in Southern Jiangsu.展开更多
The sustainability of regional rural development depends on the integrated status and the coordination between rural resources-environment conditions and rural socioeco- nomic development. In this paper a diagnostic i...The sustainability of regional rural development depends on the integrated status and the coordination between rural resources-environment conditions and rural socioeco- nomic development. In this paper a diagnostic indicator system is proposed to appraise four representative rural development models such as Mentougou model, Taicang model, Yueqing model and Qionghai model in the eastern coastal region of China from the integrated perspective of population, resources, environment, and development. In conclusion, the formation and evolution of these diverse rural deveJopment models are the direct response to the very different characteristics in the environment, market demand, and regional culture. These models are common in that their sustainability depends on the scientific guidance of the regional development functional positioning, strong intra-regional interactions, and self-adaptability to the external conditions.展开更多
Cities are the key areas for human beings to achieve sustainable development goals in the future.Estuarine cities are a special type of coastal city in urgent need of a clear definition.This paper proposed that estuar...Cities are the key areas for human beings to achieve sustainable development goals in the future.Estuarine cities are a special type of coastal city in urgent need of a clear definition.This paper proposed that estuarine cities are cities developed on the coast where rivers and oceans meet and defined four connotations,including the intersection of rivers and marine water systems,the coordinated development of land and oceans,the location advantages of connecting rivers and seas,and the important fragility of the ecological environment.We used Hydro SHEDS,OSM,GPW,and urban socioeconomic statistics and selected 50 estuarine cities with large rivers as representatives to summarize the main geographical basis and socioeconomic characteristics.Cities are primarily found in low-altitude,flat regions with average annual temperatures that mainly vary from 10℃to 25℃,relatively abundant precipitation,and extensive biological resources.There are substantial variations in the socioeconomic features of estuarine cities.We proposed eight development patterns,including open and inclusive city spirit,high-quality livable cities,high-quality development driven by innovation,integration of internal and external communication with ports and cities,construction of an international financial center,ecological environment protection and restoration,active promotion of cultural tourism,and positive international exchanges.展开更多
Objective To systematically analyze the development status of DTP pharmacy in the United States and China,and to find out the problems in China’s DTP pharmacy and put forward some countermeasures and suggestions.Meth...Objective To systematically analyze the development status of DTP pharmacy in the United States and China,and to find out the problems in China’s DTP pharmacy and put forward some countermeasures and suggestions.Methods Relevant literature was searched and reviewed to study the history,market scale and development trend of DTP pharmacy in the United States and China.Then,the problems in China’s DTP pharmacy were found out.Results and Conclusion DTP pharmacy model in the U.S.has taken shape and is maturing.The high degree of industry concentration is an important feature of the U.S.pharmacy.In contrast,China’s DTP pharmacy started late,and the industry pattern has not yet been finalized.There are still some problems in the DTP pharmacy certification and quality management.It is recommended to promote the rapid development of DTP pharmacies in China by encouraging the outflow of prescription drugs,establishing a third-party pharmacy accreditation organization and strengthening the team of licensed pharmacists and other personnel.展开更多
Rural tourism in China,has undergone a rapid development in the last three decades.It is an emerging and effective catalyst that promotes industrial restructuring,agricultural development and the upgrading of rural ar...Rural tourism in China,has undergone a rapid development in the last three decades.It is an emerging and effective catalyst that promotes industrial restructuring,agricultural development and the upgrading of rural areas.However,there remains little understanding about the core issues of rural tourism in China:the exact connotation,the principles,the development models and the future directions.This review paper identifies the key issues based on literature analysis,national statistics and press reports to form a general picture of the past,the current and the future prospects of China's rural tourism.The paper firstly addresses the definition,content and principles of rural tourism,and then provides an overview and brief evaluation of the progress and the current development models in China.Finally,based on the analysis of the experiences and problems,the authors sum up with five pathways of the future development of China's rural tourism from the perspective of rural tourism resources,product,market and promotion.展开更多
According to the to the typical practice in some less developed regions this paperre developed regions,this paper researches the theories and methods of construction of regional development models.Inaccordancc In acc...According to the to the typical practice in some less developed regions this paperre developed regions,this paper researches the theories and methods of construction of regional development models.Inaccordancc In accordance with the of region system of man-land relationship,the auther analyses the natural evolution trends of region system as wed as the internal and the spatiai structun of region system.On the basis of theoretical study and typical example analyses,the paper presents a system of regional develoment models,including forecasting models,structure analysis and planning models,spatial-location models and strategic decision models.展开更多
The Chang-63 reservoir in the Huaqing area has widely developed tight sandstone "thick sand layers, but not reservoirs characterized by rich in oil", and it is thus necessary to further study its oil and gas enrichm...The Chang-63 reservoir in the Huaqing area has widely developed tight sandstone "thick sand layers, but not reservoirs characterized by rich in oil", and it is thus necessary to further study its oil and gas enrichment law. This study builds porosity and fracture development and evolution models in different deposition environments, through core observation, casting thin section, SEM, porosity and permeability analysis, burial history analysis, and "four-property-relationships" analysis.展开更多
This survey is concerned with the new developments on existence and uniqueness of solutions of some basic models in atmospheric dynamics, such as two-and three-dimensional quasi-geostrophic models and three-dimensiona...This survey is concerned with the new developments on existence and uniqueness of solutions of some basic models in atmospheric dynamics, such as two-and three-dimensional quasi-geostrophic models and three-dimensional balanced model. The main aim of this paper is to introduce some results about the global and local (with respect to time) existence of solutions given by the authors in recent years, but others' important contributions and the literature on this subject are also quoted. We discuss briefly the relationships among the existence and uniqueness, physical instability and computational instability. In the appendixes, some key mathematical techniques in obtaining our results are presented, which are of vital importance to other problems in geophysical fluid dynamics as well.展开更多
Low permeability sandstone reservoirs in China typically have more complicated geological conditions, pore structures, and flow characteristics as compared to medium-to-high-permeability sandstone reservoirs. Traditio...Low permeability sandstone reservoirs in China typically have more complicated geological conditions, pore structures, and flow characteristics as compared to medium-to-high-permeability sandstone reservoirs. Traditional geological and seepage theories, and engineering methods are not applicable to the development of these low permeability reservoirs, and wells drilled into them often produce oil and gas at very low rates. Recent breakthroughs in reservoir exploitation technology have greatly improved the productivity of low permeability reservoirs, making them the primary target for oil exploration and extraction in China. The development theories and practices applied to low permeability reservoirs in China are reviewed in this study— based on relevant geological and engineering practices, including drilling, fracturing, recovery, and surface engineering. A unique series of technological advances that aid the development of low permeability reservoirs in China are summarized here. This study may serve as a meaningful guide in achieving scale efficiency for the development of low permeability reservoirs.展开更多
IPTV,as a newborn service,is restricted on market operation by multiple factors. Therefore,exploration is required in respect of its business,operations and service provision models. First,an IPTV industry value chain...IPTV,as a newborn service,is restricted on market operation by multiple factors. Therefore,exploration is required in respect of its business,operations and service provision models. First,an IPTV industry value chain can be formed by integrating the advantages of the existing business models of telecommunication,broadcasting and TV,and Internet industries,which helps realize win-win cooperation of all the parties on the chain. Second,plans for technology implementation and network deployment should be made after comprehensive consideration according to various development stages of the IPTV. Third,a reasonable profit allocation model may promote the growth of IPTV services. Last,market competitiveness will be improved by services bundling. Generally,IPTV will become a breakthrough point for the strategic transformation of telecom operators and meet their innovation demands. Therefore,IPTV is expected to be a promising technology helping telecom operators find more growth space in the information communication market.展开更多
Serious desertification caused by human activity and climate change,in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land,lead to severe scarcity of soil and water resources,w...Serious desertification caused by human activity and climate change,in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land,lead to severe scarcity of soil and water resources,which causes worse local agricultural conditions accordingly.Many physical properties of arsenic sandstone is complementary with that of sand,arsenic sandstone is therefore supposed to be blended to enhance water productivity and arability of sandy land.Container experiments are carried out to study the enhancement of water holding capacity of the mixture,the blending ratio of arsenic sandstone and sand,and the proper size of the arsenic sandstone particles,respectively.The results of the experiments show that particle size of 4 cm with a ratio of 1∶2 between arsenic sandstone and sand are the proper parameters on blending.Both water content and fertility increase after blending.Water use efficiency in the mixture is 2.7 times higher than that in sand by the water release curves from experiments.Therefore,a new sand control and development model,including arsenic sandstone blending with sand,efficient water irrigation management and reasonable farming system,is put forward to control and develop sandy land so that water-saving agriculture could be developed.Demonstration of potato planting about 153.1 ha in area in the Mu Us Sandy Land in China indicates that water consumption is 3018 m3/ha in the whole growth period.It means that about 61%of irrigation water can be saved compared with water use in coarse sand without treatment.Recycle economic mode and positive feedback of sand resource-crop planting-soil resource are constructed,which changes sand into arable soil and make it possible to develop water-saving agriculture on it.The proposed model will be helpful for soil-water resources utilization and management in the Mu Us Sandy Land.展开更多
Objective To develop a risk model for predicting later development of diabetic nephropathy (DN) in Chinese people with type 2 diabetes mellitus (T2DM) and evaluate its performance with independent validation. Meth...Objective To develop a risk model for predicting later development of diabetic nephropathy (DN) in Chinese people with type 2 diabetes mellitus (T2DM) and evaluate its performance with independent validation. Methods We used data collected from the project 'Comprehensive Research on the Prevention and Control of Diabetes', which was a community-based study conducted by the Jiangsu Center for Disease Control and Prevention in 2013. A total of 11,771 eligible participants were included in our study. The endpoint was a clear diagnosis of DN. Data was divided into two components: a training set for model development and a test set for validation. The Cox proportional hazard regression was used for survival analysis in men and women. The model's performance was evaluated by discrimination and calibration. Results The incidence (cases per 10,000 person-years) of DN was 9.95 (95% CI; 8.66-11.43) in women and 11.28 (95% CI; 9.77-13.03) in men. Factors including diagnosis age, location, body mass index, high-density-lipoprotein cholesterol, creatinine, hypertension, dyslipidemia, retinopathy, diet control, and physical activity were significant in the final model. The model showed high discrimination and good calibration. Conclusion The risk model for predicting DN in people with T2DM can be used in clinical practice for improving the quality of risk management and intervention.展开更多
From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and...From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.展开更多
This paper focuses on potential development models of future oil and gas exploration in South China Sea. A detailed study of current development models worldwide is performed through some examples of industry installe...This paper focuses on potential development models of future oil and gas exploration in South China Sea. A detailed study of current development models worldwide is performed through some examples of industry installed/ongoing projects and major technical issues encountered during these practice. Key technologies are discussed for the success of field development. Some of the technologies and field development experience can be used for South China Sea project. Several models are studied in field development for different scenarios,including marginal field,large oil field and gas field. With the massive investment activities,continued improved technologies,and rapidly growing pool of professionals,the offshore industry in China will soon encounter a golden period.展开更多
Promoting coordinated development of resources and environment is an important aspect of building a harmonious society and ecologically sustainable civilization. Here we provide scientific basis to promote the develop...Promoting coordinated development of resources and environment is an important aspect of building a harmonious society and ecologically sustainable civilization. Here we provide scientific basis to promote the development of ecologically sensitive civilization, via a mathematical statistics method that calculates the degree of coordinated development. This model is of great practical and social significance, providing strength to research around coordinated development of resources and economy. Based on evaluation of characteristics of the present resource environment and economic development of Shandong Peninsula city group, a coordinated measure of resource environment and economic development was calculated. Overall, the highest coordination measurement was found for Weihai, followed by Yantai, Qingdao, Ji'nan, Weifang, Rizhao, Zibo and Dongying. According to evaluation results of coordination measures for each city, we put forward suggestions for sustainable development of Shandong Peninsula region.展开更多
The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,...The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,logging and seismic data.A development model of karst reservoirs is constructed to support the high-efficiency development of gas pools.The research shows that the reservoirs in Deng 4 Member have mainly small-scale karst vugs and fractures as storage space,and can be divided into three types,fracture-vug,pore-vug and pore types.The development patterns of the karst reservoirs are determined.On the plane,the karst layers increase from 65 m to 170 m in thickness from the karst platform to the karst slope,and the high-quality reservoirs increase from 25.0 m to 42.2 m in thickness;vertically,the reservoirs at the top of Deng 4 Member appear in multiple layers,and show along-bedding and along fracture dissolution characteristics.The reservoirs at the bottom are characterized by the dissolution parallel to the water level during the karstification period,and have 3-5 large-scale fracture-cave systems.Based on the reservoir development characteristics and the genetic mechanism,three types of reservoir development models of karst reservoir are established,i.e.,bed-dissolved body,fracture-dissolved body and paleohorizon-dissolved body.The construction of karst reservoir development models and seismic response characteristics of the three types of reservoirs can provide parameter for well placement and trajectory design,and substantially improve productivity and development indices of individual wells and gas reservoirs.The designed production capacity of the gas reservoir has enhanced from the initial 3.6 billion to 6 billion cubic meters,making the profit of the reservoir development increase noticeably.展开更多
This essay tries to reveal the developmental regularity of urban-rural networking manifested by urbanization. The urban-rural networking is a reality and an inexorable trend of development. As a physical existence, th...This essay tries to reveal the developmental regularity of urban-rural networking manifested by urbanization. The urban-rural networking is a reality and an inexorable trend of development. As a physical existence, the urban-rural networking reflects a result of the interaction between cities and rural areas; it is a necessary and sufficient condition for sustaining progress of cities and rural areas. As an objective developmental tendency, it reflects an urban-rural regional economic process. The author briefly analyzes two contradictory urban-rural developmental views, and puts forward a concept of the mode of urban-rural networking development. The author also analyzes the mode from the perspectives of economics and philosophy.展开更多
A case study is presented of a regional development model for valley economies in the mountain areas of Beijing, China. The nature and framework of the valley economy model are described and the development of the mod...A case study is presented of a regional development model for valley economies in the mountain areas of Beijing, China. The nature and framework of the valley economy model are described and the development of the model, which is specific to the mountain areas of Beijing, is analyzed. Five different valley economy models applied in the Beijing mountain areas are compared. The major purpose of the valley economy model is to develop the regional economy, including the selection of appropriate industries, the allocation of industrial space, the establishment of supply chains and the integration of various industries. Pilot experiments using the valley economy model have been conducted in seven counties(districts) in Beijing: Pinggu, Huairou, Changping, Mentougou, and Fangshan districts, and Yanqing and Miyun counties. Five models for developing the Beijing mountain areas have been explored, including: creative cultural industries, characteristic industry clusters, the promotion of large tourist areas, natural scenic tourism and folk cultural tourism. Each model has its own unique features and potential to help in the regional development of mountain areas.展开更多
BACKGROUND Acute kidney injury(AKI)after coronary artery bypass graft(CABG)surgery is associated with significant morbidity and mortality.This retrospective study aimed to establish a risk score for postoperative AKI ...BACKGROUND Acute kidney injury(AKI)after coronary artery bypass graft(CABG)surgery is associated with significant morbidity and mortality.This retrospective study aimed to establish a risk score for postoperative AKI in a Chinese population.METHODS A total of 1138 patients undergoing CABG were collected from September 2018 to May 2020 and divided into a derivation and validation cohort.AKI was defined according to the Kidney Disease Improving Global Outcomes(KDIGO)criteria.Multivariable logistic regression analysis was used to determine the independent predictors of AKI,and the predictive ability of the model was determined using a receiver operating characteristic(ROC)curve.RESULTS The incidence of cardiac surgery–associated acute kidney injury(CSA-AKI)was 24.17%,and 0.53%of AKI patients required dialysis(AKI-D).Among the derivation cohort,multivariable logistic regression showed that age≥70 years,body mass index(BMI)≥25 kg/m2,estimated glomerular filtration rate(eGFR)≤60 mL/min per 1.73 m2,ejection fraction(EF)≤45%,use of statins,red blood cell transfusion,use of adrenaline,intra-aortic balloon pump(IABP)implantation,postoperative low cardiac output syndrome(LCOS)and reoperation for bleeding were independent predictors.The predictive model was scored from 0 to32 points with three risk categories.The AKI frequencies were as follows:0-8 points(15.9%),9-17 points(36.5%)and≥18 points(90.4%).The area under of the ROC curve was 0.730(95%CI:0.691-0.768)in the derivation cohort.The predictive index had good discrimination in the validation cohort,with an area under the curve of 0.735(95%CI:0.655-0.815).The model was well calibrated according to the Hosmer-Lemeshow test(P=0.372).CONCLUSION The performance of the prediction model was valid and accurate in predicting KDIGO-AKI after CABG surgery in Chinese patients,and could improve the early prognosis and clinical interventions.展开更多
With the extensive use of the Internet and mobile technology, E-commerce in China has shown tremendous growth advantages and market potential, especially in promoting the access of eco-agriculture products. The E-comm...With the extensive use of the Internet and mobile technology, E-commerce in China has shown tremendous growth advantages and market potential, especially in promoting the access of eco-agriculture products. The E-commerce of agriculture products has shown diversification on the mainstay. "Three products, one indication"(pollution-free, green product, organic product, geographical indication) has becomes the primary character. Although the market of fresh products occupies a limited and meager profit, the blue sea effect has caused capital to enter into a large-scale development. It is very clearly shown after the analysis that the market of eco-agricultural E-commerce is vast and the expansionist policy for E-commerce environment is favorable. Meanwhile the required hardware and software of network in E-commerce are basically equipped with rapid development of service technology and strong driving force for innovation and development as well as an endless stream of new models and platforms. The whole phrase of development can be divided into five major stages. Through the analysis of five perspectives, such as platform, driver, participant, food supplier and Taobao, 16 types of agro-products E-commerce models and their different types of e-payment support systems are summarized, revealing the two major bottlenecks of development, namely the markets with limited share and low profit-making and the impact of cold chain services on E-commerce development. The thesis finally fortells the ten trends for the future development.展开更多
基金Supported by the National Natural Science Foundation of China(70901035)~~
文摘[Objective] To investigate the appropriate low-carbon agriculture model in Southern Jiangsu Province. [Method] Through the analysis of regional features in Southern Jiangsu and several matured low-carbon agriculture development models at present, the low-carbon agriculture development modes suitable for Southern Jiangsu were investigated, and corresponding supporting measures for the development of the models were put forward. [Result] Low-carbon agriculture is the environment- friendly agriculture which achieves low emissions, low pollution, high efficiency and high-yield through efficient recycling of energy and resources and continuous im- provements on ecological environment. With a variety of development models, the specific development model for practical use should be determined according to the local conditions, and supported by corresponding supporting measures, to achieve the rapid development of low-carbon agriculture. [Conclusion] This study laid the foundation for the development of low-carbon agriculture model in Southern Jiangsu.
基金National Natural Science Foundation of China, No.40635029 No.40871257Knowledge Innovation Program of Chinese Academy of Sciences, No.KSCX-YW-09
文摘The sustainability of regional rural development depends on the integrated status and the coordination between rural resources-environment conditions and rural socioeco- nomic development. In this paper a diagnostic indicator system is proposed to appraise four representative rural development models such as Mentougou model, Taicang model, Yueqing model and Qionghai model in the eastern coastal region of China from the integrated perspective of population, resources, environment, and development. In conclusion, the formation and evolution of these diverse rural deveJopment models are the direct response to the very different characteristics in the environment, market demand, and regional culture. These models are common in that their sustainability depends on the scientific guidance of the regional development functional positioning, strong intra-regional interactions, and self-adaptability to the external conditions.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23100301The Chinese Academy of Sciences Basic Frontier Science Research Program from 0 to 1 Original Innovation Project,No.ZDBS-LYD-QC005National Natural Science Foundation of China,No.42171204。
文摘Cities are the key areas for human beings to achieve sustainable development goals in the future.Estuarine cities are a special type of coastal city in urgent need of a clear definition.This paper proposed that estuarine cities are cities developed on the coast where rivers and oceans meet and defined four connotations,including the intersection of rivers and marine water systems,the coordinated development of land and oceans,the location advantages of connecting rivers and seas,and the important fragility of the ecological environment.We used Hydro SHEDS,OSM,GPW,and urban socioeconomic statistics and selected 50 estuarine cities with large rivers as representatives to summarize the main geographical basis and socioeconomic characteristics.Cities are primarily found in low-altitude,flat regions with average annual temperatures that mainly vary from 10℃to 25℃,relatively abundant precipitation,and extensive biological resources.There are substantial variations in the socioeconomic features of estuarine cities.We proposed eight development patterns,including open and inclusive city spirit,high-quality livable cities,high-quality development driven by innovation,integration of internal and external communication with ports and cities,construction of an international financial center,ecological environment protection and restoration,active promotion of cultural tourism,and positive international exchanges.
文摘Objective To systematically analyze the development status of DTP pharmacy in the United States and China,and to find out the problems in China’s DTP pharmacy and put forward some countermeasures and suggestions.Methods Relevant literature was searched and reviewed to study the history,market scale and development trend of DTP pharmacy in the United States and China.Then,the problems in China’s DTP pharmacy were found out.Results and Conclusion DTP pharmacy model in the U.S.has taken shape and is maturing.The high degree of industry concentration is an important feature of the U.S.pharmacy.In contrast,China’s DTP pharmacy started late,and the industry pattern has not yet been finalized.There are still some problems in the DTP pharmacy certification and quality management.It is recommended to promote the rapid development of DTP pharmacies in China by encouraging the outflow of prescription drugs,establishing a third-party pharmacy accreditation organization and strengthening the team of licensed pharmacists and other personnel.
基金supported by a grant from the major projects of the National Social Science Foundation of China (10zd&051)National Natural Science Foundation Item of China(No.41171435 )from the United Nations(UNDP/CPR/040/SPA)
文摘Rural tourism in China,has undergone a rapid development in the last three decades.It is an emerging and effective catalyst that promotes industrial restructuring,agricultural development and the upgrading of rural areas.However,there remains little understanding about the core issues of rural tourism in China:the exact connotation,the principles,the development models and the future directions.This review paper identifies the key issues based on literature analysis,national statistics and press reports to form a general picture of the past,the current and the future prospects of China's rural tourism.The paper firstly addresses the definition,content and principles of rural tourism,and then provides an overview and brief evaluation of the progress and the current development models in China.Finally,based on the analysis of the experiences and problems,the authors sum up with five pathways of the future development of China's rural tourism from the perspective of rural tourism resources,product,market and promotion.
文摘According to the to the typical practice in some less developed regions this paperre developed regions,this paper researches the theories and methods of construction of regional development models.Inaccordancc In accordance with the of region system of man-land relationship,the auther analyses the natural evolution trends of region system as wed as the internal and the spatiai structun of region system.On the basis of theoretical study and typical example analyses,the paper presents a system of regional develoment models,including forecasting models,structure analysis and planning models,spatial-location models and strategic decision models.
文摘The Chang-63 reservoir in the Huaqing area has widely developed tight sandstone "thick sand layers, but not reservoirs characterized by rich in oil", and it is thus necessary to further study its oil and gas enrichment law. This study builds porosity and fracture development and evolution models in different deposition environments, through core observation, casting thin section, SEM, porosity and permeability analysis, burial history analysis, and "four-property-relationships" analysis.
文摘This survey is concerned with the new developments on existence and uniqueness of solutions of some basic models in atmospheric dynamics, such as two-and three-dimensional quasi-geostrophic models and three-dimensional balanced model. The main aim of this paper is to introduce some results about the global and local (with respect to time) existence of solutions given by the authors in recent years, but others' important contributions and the literature on this subject are also quoted. We discuss briefly the relationships among the existence and uniqueness, physical instability and computational instability. In the appendixes, some key mathematical techniques in obtaining our results are presented, which are of vital importance to other problems in geophysical fluid dynamics as well.
基金support by the National Key Research and Development Program of China(Grant No.2018YFA0702400)is gratefully acknowledged.
文摘Low permeability sandstone reservoirs in China typically have more complicated geological conditions, pore structures, and flow characteristics as compared to medium-to-high-permeability sandstone reservoirs. Traditional geological and seepage theories, and engineering methods are not applicable to the development of these low permeability reservoirs, and wells drilled into them often produce oil and gas at very low rates. Recent breakthroughs in reservoir exploitation technology have greatly improved the productivity of low permeability reservoirs, making them the primary target for oil exploration and extraction in China. The development theories and practices applied to low permeability reservoirs in China are reviewed in this study— based on relevant geological and engineering practices, including drilling, fracturing, recovery, and surface engineering. A unique series of technological advances that aid the development of low permeability reservoirs in China are summarized here. This study may serve as a meaningful guide in achieving scale efficiency for the development of low permeability reservoirs.
文摘IPTV,as a newborn service,is restricted on market operation by multiple factors. Therefore,exploration is required in respect of its business,operations and service provision models. First,an IPTV industry value chain can be formed by integrating the advantages of the existing business models of telecommunication,broadcasting and TV,and Internet industries,which helps realize win-win cooperation of all the parties on the chain. Second,plans for technology implementation and network deployment should be made after comprehensive consideration according to various development stages of the IPTV. Third,a reasonable profit allocation model may promote the growth of IPTV services. Last,market competitiveness will be improved by services bundling. Generally,IPTV will become a breakthrough point for the strategic transformation of telecom operators and meet their innovation demands. Therefore,IPTV is expected to be a promising technology helping telecom operators find more growth space in the information communication market.
基金Under the auspices of National Natural Science Foundation of China(No.51079120)Education Department Research Program of Shaanxi Province(No.12JK0481)Water Conservancy Science and Technology Plan of Shaanxi Province(No.2012-07)
文摘Serious desertification caused by human activity and climate change,in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land,lead to severe scarcity of soil and water resources,which causes worse local agricultural conditions accordingly.Many physical properties of arsenic sandstone is complementary with that of sand,arsenic sandstone is therefore supposed to be blended to enhance water productivity and arability of sandy land.Container experiments are carried out to study the enhancement of water holding capacity of the mixture,the blending ratio of arsenic sandstone and sand,and the proper size of the arsenic sandstone particles,respectively.The results of the experiments show that particle size of 4 cm with a ratio of 1∶2 between arsenic sandstone and sand are the proper parameters on blending.Both water content and fertility increase after blending.Water use efficiency in the mixture is 2.7 times higher than that in sand by the water release curves from experiments.Therefore,a new sand control and development model,including arsenic sandstone blending with sand,efficient water irrigation management and reasonable farming system,is put forward to control and develop sandy land so that water-saving agriculture could be developed.Demonstration of potato planting about 153.1 ha in area in the Mu Us Sandy Land in China indicates that water consumption is 3018 m3/ha in the whole growth period.It means that about 61%of irrigation water can be saved compared with water use in coarse sand without treatment.Recycle economic mode and positive feedback of sand resource-crop planting-soil resource are constructed,which changes sand into arable soil and make it possible to develop water-saving agriculture on it.The proposed model will be helpful for soil-water resources utilization and management in the Mu Us Sandy Land.
基金supported by grants from Jiangsu Provincial Medical Innovation Team Program[grant number K201105]Jiangsu Provincial Fourth‘333 Project’[grant number BRA2013107]
文摘Objective To develop a risk model for predicting later development of diabetic nephropathy (DN) in Chinese people with type 2 diabetes mellitus (T2DM) and evaluate its performance with independent validation. Methods We used data collected from the project 'Comprehensive Research on the Prevention and Control of Diabetes', which was a community-based study conducted by the Jiangsu Center for Disease Control and Prevention in 2013. A total of 11,771 eligible participants were included in our study. The endpoint was a clear diagnosis of DN. Data was divided into two components: a training set for model development and a test set for validation. The Cox proportional hazard regression was used for survival analysis in men and women. The model's performance was evaluated by discrimination and calibration. Results The incidence (cases per 10,000 person-years) of DN was 9.95 (95% CI; 8.66-11.43) in women and 11.28 (95% CI; 9.77-13.03) in men. Factors including diagnosis age, location, body mass index, high-density-lipoprotein cholesterol, creatinine, hypertension, dyslipidemia, retinopathy, diet control, and physical activity were significant in the final model. The model showed high discrimination and good calibration. Conclusion The risk model for predicting DN in people with T2DM can be used in clinical practice for improving the quality of risk management and intervention.
文摘From the process of sedimentation the mathematical relationships among deposition Volume and powder properties as well as sedimentation parameters were deduced. Based on the formula a mathematical model was set up and simulated through the computer. At last the validity of mathematical model was supported by the representative experiment on Ti-Mo system FGM prepared by co-sedimentation.
文摘This paper focuses on potential development models of future oil and gas exploration in South China Sea. A detailed study of current development models worldwide is performed through some examples of industry installed/ongoing projects and major technical issues encountered during these practice. Key technologies are discussed for the success of field development. Some of the technologies and field development experience can be used for South China Sea project. Several models are studied in field development for different scenarios,including marginal field,large oil field and gas field. With the massive investment activities,continued improved technologies,and rapidly growing pool of professionals,the offshore industry in China will soon encounter a golden period.
基金supported by Shandong Province Bureau of Statistics(No.KT15019)
文摘Promoting coordinated development of resources and environment is an important aspect of building a harmonious society and ecologically sustainable civilization. Here we provide scientific basis to promote the development of ecologically sensitive civilization, via a mathematical statistics method that calculates the degree of coordinated development. This model is of great practical and social significance, providing strength to research around coordinated development of resources and economy. Based on evaluation of characteristics of the present resource environment and economic development of Shandong Peninsula city group, a coordinated measure of resource environment and economic development was calculated. Overall, the highest coordination measurement was found for Weihai, followed by Yantai, Qingdao, Ji'nan, Weifang, Rizhao, Zibo and Dongying. According to evaluation results of coordination measures for each city, we put forward suggestions for sustainable development of Shandong Peninsula region.
基金Supported by the National Science and Technology Major Project of China(2016ZX05015)PetroChina Science and Technology Project(2021DJ1504).
文摘The reservoir space,types and distribution characteristics of karst carbonate gas reservoirs in the fourth member of Sinian Dengying Formation(Deng 4 Member)in central Sichuan Basin are analyzed based on the drilling,logging and seismic data.A development model of karst reservoirs is constructed to support the high-efficiency development of gas pools.The research shows that the reservoirs in Deng 4 Member have mainly small-scale karst vugs and fractures as storage space,and can be divided into three types,fracture-vug,pore-vug and pore types.The development patterns of the karst reservoirs are determined.On the plane,the karst layers increase from 65 m to 170 m in thickness from the karst platform to the karst slope,and the high-quality reservoirs increase from 25.0 m to 42.2 m in thickness;vertically,the reservoirs at the top of Deng 4 Member appear in multiple layers,and show along-bedding and along fracture dissolution characteristics.The reservoirs at the bottom are characterized by the dissolution parallel to the water level during the karstification period,and have 3-5 large-scale fracture-cave systems.Based on the reservoir development characteristics and the genetic mechanism,three types of reservoir development models of karst reservoir are established,i.e.,bed-dissolved body,fracture-dissolved body and paleohorizon-dissolved body.The construction of karst reservoir development models and seismic response characteristics of the three types of reservoirs can provide parameter for well placement and trajectory design,and substantially improve productivity and development indices of individual wells and gas reservoirs.The designed production capacity of the gas reservoir has enhanced from the initial 3.6 billion to 6 billion cubic meters,making the profit of the reservoir development increase noticeably.
基金Project A model of spatial process: on the networking development of modern rural-urban supported by NSFC (Grand No.49971030)
文摘This essay tries to reveal the developmental regularity of urban-rural networking manifested by urbanization. The urban-rural networking is a reality and an inexorable trend of development. As a physical existence, the urban-rural networking reflects a result of the interaction between cities and rural areas; it is a necessary and sufficient condition for sustaining progress of cities and rural areas. As an objective developmental tendency, it reflects an urban-rural regional economic process. The author briefly analyzes two contradictory urban-rural developmental views, and puts forward a concept of the mode of urban-rural networking development. The author also analyzes the mode from the perspectives of economics and philosophy.
基金supported by the National Natural Science Foundation of China(Grant No.4120112941125005)+2 种基金the Hunan Provincial Natural Science Foundation of China(Grant No.12JJ3037)the Hunan Provincial Philosophy and Social Sciences Foundation of China(Grant No.11JD06)the Hengyang Normal University Youth Foundation in Hunan Province of China(Grant No.11A27)
文摘A case study is presented of a regional development model for valley economies in the mountain areas of Beijing, China. The nature and framework of the valley economy model are described and the development of the model, which is specific to the mountain areas of Beijing, is analyzed. Five different valley economy models applied in the Beijing mountain areas are compared. The major purpose of the valley economy model is to develop the regional economy, including the selection of appropriate industries, the allocation of industrial space, the establishment of supply chains and the integration of various industries. Pilot experiments using the valley economy model have been conducted in seven counties(districts) in Beijing: Pinggu, Huairou, Changping, Mentougou, and Fangshan districts, and Yanqing and Miyun counties. Five models for developing the Beijing mountain areas have been explored, including: creative cultural industries, characteristic industry clusters, the promotion of large tourist areas, natural scenic tourism and folk cultural tourism. Each model has its own unique features and potential to help in the regional development of mountain areas.
基金supported by National Natural S cience Foundation of China(81570373)。
文摘BACKGROUND Acute kidney injury(AKI)after coronary artery bypass graft(CABG)surgery is associated with significant morbidity and mortality.This retrospective study aimed to establish a risk score for postoperative AKI in a Chinese population.METHODS A total of 1138 patients undergoing CABG were collected from September 2018 to May 2020 and divided into a derivation and validation cohort.AKI was defined according to the Kidney Disease Improving Global Outcomes(KDIGO)criteria.Multivariable logistic regression analysis was used to determine the independent predictors of AKI,and the predictive ability of the model was determined using a receiver operating characteristic(ROC)curve.RESULTS The incidence of cardiac surgery–associated acute kidney injury(CSA-AKI)was 24.17%,and 0.53%of AKI patients required dialysis(AKI-D).Among the derivation cohort,multivariable logistic regression showed that age≥70 years,body mass index(BMI)≥25 kg/m2,estimated glomerular filtration rate(eGFR)≤60 mL/min per 1.73 m2,ejection fraction(EF)≤45%,use of statins,red blood cell transfusion,use of adrenaline,intra-aortic balloon pump(IABP)implantation,postoperative low cardiac output syndrome(LCOS)and reoperation for bleeding were independent predictors.The predictive model was scored from 0 to32 points with three risk categories.The AKI frequencies were as follows:0-8 points(15.9%),9-17 points(36.5%)and≥18 points(90.4%).The area under of the ROC curve was 0.730(95%CI:0.691-0.768)in the derivation cohort.The predictive index had good discrimination in the validation cohort,with an area under the curve of 0.735(95%CI:0.655-0.815).The model was well calibrated according to the Hosmer-Lemeshow test(P=0.372).CONCLUSION The performance of the prediction model was valid and accurate in predicting KDIGO-AKI after CABG surgery in Chinese patients,and could improve the early prognosis and clinical interventions.
文摘With the extensive use of the Internet and mobile technology, E-commerce in China has shown tremendous growth advantages and market potential, especially in promoting the access of eco-agriculture products. The E-commerce of agriculture products has shown diversification on the mainstay. "Three products, one indication"(pollution-free, green product, organic product, geographical indication) has becomes the primary character. Although the market of fresh products occupies a limited and meager profit, the blue sea effect has caused capital to enter into a large-scale development. It is very clearly shown after the analysis that the market of eco-agricultural E-commerce is vast and the expansionist policy for E-commerce environment is favorable. Meanwhile the required hardware and software of network in E-commerce are basically equipped with rapid development of service technology and strong driving force for innovation and development as well as an endless stream of new models and platforms. The whole phrase of development can be divided into five major stages. Through the analysis of five perspectives, such as platform, driver, participant, food supplier and Taobao, 16 types of agro-products E-commerce models and their different types of e-payment support systems are summarized, revealing the two major bottlenecks of development, namely the markets with limited share and low profit-making and the impact of cold chain services on E-commerce development. The thesis finally fortells the ten trends for the future development.