Aming at water conservancy project visualization, a hidden-removal method of dam perspective drawings is realized by building a hidden-removal mathematical model for overlapping points location to set up the hidden re...Aming at water conservancy project visualization, a hidden-removal method of dam perspective drawings is realized by building a hidden-removal mathematical model for overlapping points location to set up the hidden relationship among point and plane, plane and plane in space. On this basis, as an example of panel rockfill dam, a dam hidden-removal perspective drawing is generated in different directions and different visual angles through adapting VC＋＋ and OpenGL visualizing technology. The results show that the data construction of the model is simple which can overcome the disadvantages of considerable and complicated calculation. This method also provides the new means to draw hidden-removal perspective drawings for those landforms and ground objects.展开更多
Taking spiral chute as example, a method of unfolded drawings and views about irregular spiral surface is introduced. The surface is undevelopable and too complicated to get its views or to draw unfolded drawings by m...Taking spiral chute as example, a method of unfolded drawings and views about irregular spiral surface is introduced. The surface is undevelopable and too complicated to get its views or to draw unfolded drawings by manual method. In this article, a series of the boundary equations of the spiral chute are derived by the movement rule of coal flow, and the solid and views of the spiral chute are generated based on redevelopment of SolidWorks. Unfolded drawing is drawn applying triangular development principle. The views and unfolded drawings not only are produced automatically, precisely and parameterized, but also involve more technological information. So it has an important significance on the irregular spiral surface＇s developments and processing.展开更多
Elbow draft-tubes are widely used in large- and medium-sized hydropower stations in many countries. During the application, handling the somatotype of elbow tubes has been found challenging： in order to maintain the ...Elbow draft-tubes are widely used in large- and medium-sized hydropower stations in many countries. During the application, handling the somatotype of elbow tubes has been found challenging： in order to maintain the designed shape of draft tube and to meet the requirement of construction lofting, the configuration of reinforcing bars and the fabrication of templates, the geometry of elbow tubes has to be accurately calculated to draw engineering graphics. Based on the derived equations in this paper, the motion of elbow tube curve envelope is simulated by using computers, which shows directly the smoothness of the curve and provides dynamic simulation for the study and optimization of the design and construction of elbow draft tubes, along with the front view and bottom view.展开更多
APIs of CAD system could be encapsulated to construct web services so as to provide standard access interfaces for web-based cooperative design. However, lack of semantic supporting make integration of heterogeneous m...APIs of CAD system could be encapsulated to construct web services so as to provide standard access interfaces for web-based cooperative design. However, lack of semantic supporting make integration of heterogeneous modelling system limited to operational level. On the purpose of carrying out cooperative design in a flexible cloud environment, an intelligent and effective support mechanism is needed for mass and complex interaction in cooperative work. Therefore, Ontology-based Geometry Modeling Services Environment （OGMSE） is provided to realize a knowledge-level geometry modeling so as to supported semantic 3D model management and intelligent operation support. First, CAD APIs are encapsulated into web service for web invocation. Then, ontology contained structural semantic and operational semantic is built for management of models and modeling process. Lastly, conception-driven modeling mechanism is built to invocate service according to interaction requirement, thus to realize conception-level cooperative design. Based on an open geometry engine, a prototype system has been developed. The result shows that the approach provides a reference direction for large-scale application on the network.展开更多
Based on the necessity of three dimensional modeling with computer in teaching reform, this paper is the summarization of reform practice of teaching engineering drawing in our institute. The teaching reform begins wi...Based on the necessity of three dimensional modeling with computer in teaching reform, this paper is the summarization of reform practice of teaching engineering drawing in our institute. The teaching reform begins with three dimensional modeling that used computer instead of board. On the basis of target of teaching reform, set of teaching content, arrangement of class hour and teaching method, the research of teaching practice have been done, and very good effects in teaching of engineering drawing have been achieved.展开更多
Superior anti-icing and active deicing multifunctional surfaces are highly desired in outdoor infrastructure and work of aircraft,automobiles,wind turbines,power transmission,etc.Herein,inspired by microstructures and...Superior anti-icing and active deicing multifunctional surfaces are highly desired in outdoor infrastructure and work of aircraft,automobiles,wind turbines,power transmission,etc.Herein,inspired by microstructures and functions of natural opal and Nepenthes pitcher plants,we present a novel multifunctional inverse opal slippery anti-icing surface(IOSAS)by employing a combined method of colloidal nanoparticles self-assembly,microstructure mold replication,and hydrophobic lubricating fluid infiltration.Because of the 3D long range ordered nanoscale porous structure of artificial inverse opal,the lubricating liquid could wick into,wet,and stably adhere to IOSAS,forming thousands of solid-liquid interfaces and defect-free and inert slippery surface.Thus,the IOSAS was imparted with inhibiting ice nucleation property and hindering heat transfer and ice crystals’growth characteristics.Owing to the existence of a thin liquid layer on the surface,the mechanical interlock between porous substrate and ice is greatly weakened,which imparts the slippery surface with low ice adhesion strength,and the frozen droplet and ice bulk could be easily removed.In addition,we have demonstrated that the supercooled IOSAS has no adhesion to moving water droplets,while various subcooled metal surfaces are adhesive,and this exhibits liquid-infused inverse opal surfaces dynamic low-temperature water-repellent performance.These characteristics endow IOSAS with multifunctional anti-icing performances,making it a promising option for a wide range of ice-phobic applications.展开更多
基金Supported by National Natural Science Foundation of China (50779005)
文摘Aming at water conservancy project visualization, a hidden-removal method of dam perspective drawings is realized by building a hidden-removal mathematical model for overlapping points location to set up the hidden relationship among point and plane, plane and plane in space. On this basis, as an example of panel rockfill dam, a dam hidden-removal perspective drawing is generated in different directions and different visual angles through adapting VC＋＋ and OpenGL visualizing technology. The results show that the data construction of the model is simple which can overcome the disadvantages of considerable and complicated calculation. This method also provides the new means to draw hidden-removal perspective drawings for those landforms and ground objects.
基金Supported by the National Natural Science Foundation,China (No.51005237)the Postdoctoral Science Foundation,China (No.20100471407)
文摘Taking spiral chute as example, a method of unfolded drawings and views about irregular spiral surface is introduced. The surface is undevelopable and too complicated to get its views or to draw unfolded drawings by manual method. In this article, a series of the boundary equations of the spiral chute are derived by the movement rule of coal flow, and the solid and views of the spiral chute are generated based on redevelopment of SolidWorks. Unfolded drawing is drawn applying triangular development principle. The views and unfolded drawings not only are produced automatically, precisely and parameterized, but also involve more technological information. So it has an important significance on the irregular spiral surface＇s developments and processing.
基金Supported by Open Fund of Key Laboratory of Ministry of Education of Hydraulic and Waterway Engineering of Chongqing Jiaotong University Province and Department Construction together(SLK2009A04)
文摘Elbow draft-tubes are widely used in large- and medium-sized hydropower stations in many countries. During the application, handling the somatotype of elbow tubes has been found challenging： in order to maintain the designed shape of draft tube and to meet the requirement of construction lofting, the configuration of reinforcing bars and the fabrication of templates, the geometry of elbow tubes has to be accurately calculated to draw engineering graphics. Based on the derived equations in this paper, the motion of elbow tube curve envelope is simulated by using computers, which shows directly the smoothness of the curve and provides dynamic simulation for the study and optimization of the design and construction of elbow draft tubes, along with the front view and bottom view.
基金Supported by Shanghai Science and Technology Projects (09DZ1121500)
文摘APIs of CAD system could be encapsulated to construct web services so as to provide standard access interfaces for web-based cooperative design. However, lack of semantic supporting make integration of heterogeneous modelling system limited to operational level. On the purpose of carrying out cooperative design in a flexible cloud environment, an intelligent and effective support mechanism is needed for mass and complex interaction in cooperative work. Therefore, Ontology-based Geometry Modeling Services Environment （OGMSE） is provided to realize a knowledge-level geometry modeling so as to supported semantic 3D model management and intelligent operation support. First, CAD APIs are encapsulated into web service for web invocation. Then, ontology contained structural semantic and operational semantic is built for management of models and modeling process. Lastly, conception-driven modeling mechanism is built to invocate service according to interaction requirement, thus to realize conception-level cooperative design. Based on an open geometry engine, a prototype system has been developed. The result shows that the approach provides a reference direction for large-scale application on the network.
基金Supported by Beijing City Institution of Higher Learning Talent Education Program Project Foundation (PHR200906213PHR201007234)
文摘Based on the necessity of three dimensional modeling with computer in teaching reform, this paper is the summarization of reform practice of teaching engineering drawing in our institute. The teaching reform begins with three dimensional modeling that used computer instead of board. On the basis of target of teaching reform, set of teaching content, arrangement of class hour and teaching method, the research of teaching practice have been done, and very good effects in teaching of engineering drawing have been achieved.
基金supported by the National Natural Science Foundation of China(Grant Nos.51725602 and 52036006)the Scientific Research Foundation of Graduate School of Southeast University(Grant No.YBPY 2113).
文摘Superior anti-icing and active deicing multifunctional surfaces are highly desired in outdoor infrastructure and work of aircraft,automobiles,wind turbines,power transmission,etc.Herein,inspired by microstructures and functions of natural opal and Nepenthes pitcher plants,we present a novel multifunctional inverse opal slippery anti-icing surface(IOSAS)by employing a combined method of colloidal nanoparticles self-assembly,microstructure mold replication,and hydrophobic lubricating fluid infiltration.Because of the 3D long range ordered nanoscale porous structure of artificial inverse opal,the lubricating liquid could wick into,wet,and stably adhere to IOSAS,forming thousands of solid-liquid interfaces and defect-free and inert slippery surface.Thus,the IOSAS was imparted with inhibiting ice nucleation property and hindering heat transfer and ice crystals’growth characteristics.Owing to the existence of a thin liquid layer on the surface,the mechanical interlock between porous substrate and ice is greatly weakened,which imparts the slippery surface with low ice adhesion strength,and the frozen droplet and ice bulk could be easily removed.In addition,we have demonstrated that the supercooled IOSAS has no adhesion to moving water droplets,while various subcooled metal surfaces are adhesive,and this exhibits liquid-infused inverse opal surfaces dynamic low-temperature water-repellent performance.These characteristics endow IOSAS with multifunctional anti-icing performances,making it a promising option for a wide range of ice-phobic applications.
