Since the founding of new China,the maize production pattern took on characteristic of " northern expansion and western movement" : there were great changes in ranking of main producing provinces; southern p...Since the founding of new China,the maize production pattern took on characteristic of " northern expansion and western movement" : there were great changes in ranking of main producing provinces; southern planting area gradually shrank,while central and northern planting area gradually expanded; apart from traditional main producing regions such as northeastern,north China,and southwestern regions,Shanxi- Shaanxi region and northwest region are gradually forming. To further analyze factors promoting changes in maize production pattern,based on 1987- 2013 panel data,we carried our empirical study and obtained five influencing factors: resource endowment,economic environment,market environment,technical conditions,and policies. Per capita farmland,multiple cropping index,water conservancy and irrigation,and benefit cost ratio,and traffic and transportation policies exert positive effect,non-agricultural employment level exerts negative effect,and the significance of natural disasters,market price,and science and technology are inadequate.展开更多
The creation of hollow out art includes a variety of materials, techniques and categories, its content mostly emphasizes the ancient philosophy performance of the alternation of virtual and real, and Yin-Yang depends ...The creation of hollow out art includes a variety of materials, techniques and categories, its content mostly emphasizes the ancient philosophy performance of the alternation of virtual and real, and Yin-Yang depends on the essence of Chinese culture deduction. If this feature is applied to product design, in addition to emphasizing functional orientation, this traditional arts integration with the new media, will give users a different visual inspire. This thesis is mainly in view of the importance of hollow out art in Chinese cultural heritage, and the 3D hollow out production craft has gradually lost. Therefore, the Delaunay triangle is constructed based on the Convex Hull interpolation algorithm, and the Voronoi Diagram feature is constructed based on the Divide and Conquer algorithm. And with Rhino modeling software as the main body, combined with the application of the parametric plug-in design program (GH), the 3D models of the parametric creative hollow pen holder and the parametric creative hollow lampshade were respectively completed. The traditional craftsmanship is integrated into the modern manufacturing process with innovative techniques, and the Chinese cultural spirit and beauty of nature are successfully connected.展开更多
Reservoirs characterized by high temperature,high-pressure,medium high cementation strength,low porosity,and low permeability,in general,are not affected by sand production issues.Since 2009,however,it is known that c...Reservoirs characterized by high temperature,high-pressure,medium high cementation strength,low porosity,and low permeability,in general,are not affected by sand production issues.Since 2009,however,it is known that cases exists where sand is present and may represent a significant technical problem(e.g.,the the Dina II condensate gas field).In the present study,the main factors affecting sand production in this type of reservoir are considered(mechanical properties,stress fields,production system,completion method and gas flow pattern changes during the production process).On this basis,a new liquid-solid coupled porous elasto-plastic 3D sand production model is introduced and validated through comparison with effective sand production data.The related prediction errors are found to be within 15%,which represents the necessary prerequisite for the utilization of such a model for the elaboration of sand prevention measures.展开更多
Cost-benefit analysis and breakeven point were used to analyze the production cost and economic benefit of tilapia pond monoculture and polyculture.From the aspects of tilapia production and economic benefit,this pape...Cost-benefit analysis and breakeven point were used to analyze the production cost and economic benefit of tilapia pond monoculture and polyculture.From the aspects of tilapia production and economic benefit,this paper summarized the current production status and the characteristics of tilapia industry development and analyzed its developing trend.The results indicated that feed cost,pond rates and labor cost are the main production costs,and the production cost of polyculture is significantly lower than that of monoculture.Through comparative analysis,it is proposed that the tilapia industry should be reasonably guided to the intensive,standardized and pollution-free direction.Specifically,it is necessary to improve the coverage of improved varieties,strengthen disease prevention and control and promote the healthy farming model of tilapia.We also should strengthen the training of tilapia production techniques and the quality and safety testing of tilapia products,and accelerate the development of tilapia industrialization,so as to promote the sustainable and healthy development of tilapia industry.展开更多
文摘Since the founding of new China,the maize production pattern took on characteristic of " northern expansion and western movement" : there were great changes in ranking of main producing provinces; southern planting area gradually shrank,while central and northern planting area gradually expanded; apart from traditional main producing regions such as northeastern,north China,and southwestern regions,Shanxi- Shaanxi region and northwest region are gradually forming. To further analyze factors promoting changes in maize production pattern,based on 1987- 2013 panel data,we carried our empirical study and obtained five influencing factors: resource endowment,economic environment,market environment,technical conditions,and policies. Per capita farmland,multiple cropping index,water conservancy and irrigation,and benefit cost ratio,and traffic and transportation policies exert positive effect,non-agricultural employment level exerts negative effect,and the significance of natural disasters,market price,and science and technology are inadequate.
文摘The creation of hollow out art includes a variety of materials, techniques and categories, its content mostly emphasizes the ancient philosophy performance of the alternation of virtual and real, and Yin-Yang depends on the essence of Chinese culture deduction. If this feature is applied to product design, in addition to emphasizing functional orientation, this traditional arts integration with the new media, will give users a different visual inspire. This thesis is mainly in view of the importance of hollow out art in Chinese cultural heritage, and the 3D hollow out production craft has gradually lost. Therefore, the Delaunay triangle is constructed based on the Convex Hull interpolation algorithm, and the Voronoi Diagram feature is constructed based on the Divide and Conquer algorithm. And with Rhino modeling software as the main body, combined with the application of the parametric plug-in design program (GH), the 3D models of the parametric creative hollow pen holder and the parametric creative hollow lampshade were respectively completed. The traditional craftsmanship is integrated into the modern manufacturing process with innovative techniques, and the Chinese cultural spirit and beauty of nature are successfully connected.
基金This study has been supported by the Major Science and Technology Project“Comprehensive Research of Exploration Matching and Application of New Technology”(2016ZX5051-3)of CNPC.
文摘Reservoirs characterized by high temperature,high-pressure,medium high cementation strength,low porosity,and low permeability,in general,are not affected by sand production issues.Since 2009,however,it is known that cases exists where sand is present and may represent a significant technical problem(e.g.,the the Dina II condensate gas field).In the present study,the main factors affecting sand production in this type of reservoir are considered(mechanical properties,stress fields,production system,completion method and gas flow pattern changes during the production process).On this basis,a new liquid-solid coupled porous elasto-plastic 3D sand production model is introduced and validated through comparison with effective sand production data.The related prediction errors are found to be within 15%,which represents the necessary prerequisite for the utilization of such a model for the elaboration of sand prevention measures.
基金Supported by the 2018 Guangxi Young and Middle-aged Teachers’Basic Ability Improvement Project(2018KY0612)the Independent Research Project of Guangxi Key Laboratory Beibu Gulf Marine Biodiversity Conservation(2018ZB05)+2 种基金High-level Talent Research Start-up Project of Qinzhou University(2017KYQD215)2018 Guangxi Higher Education Reform Project(2018JGB334)Special Fund for Specially-invited Experts in Guangxi
文摘Cost-benefit analysis and breakeven point were used to analyze the production cost and economic benefit of tilapia pond monoculture and polyculture.From the aspects of tilapia production and economic benefit,this paper summarized the current production status and the characteristics of tilapia industry development and analyzed its developing trend.The results indicated that feed cost,pond rates and labor cost are the main production costs,and the production cost of polyculture is significantly lower than that of monoculture.Through comparative analysis,it is proposed that the tilapia industry should be reasonably guided to the intensive,standardized and pollution-free direction.Specifically,it is necessary to improve the coverage of improved varieties,strengthen disease prevention and control and promote the healthy farming model of tilapia.We also should strengthen the training of tilapia production techniques and the quality and safety testing of tilapia products,and accelerate the development of tilapia industrialization,so as to promote the sustainable and healthy development of tilapia industry.
