Continent subduction is one of the hot research problems in geoscience. New models presented here have been set up and two-dimensional numerical modeling research on the possibility of continental subduction has been ...Continent subduction is one of the hot research problems in geoscience. New models presented here have been set up and two-dimensional numerical modeling research on the possibility of continental subduction has been made with the finite element software, ANSYS, based on documentary evidence and reasonable assumptions that the subduction of oceanic crust has occurred, the subduction of continental crust can take place and the process can be simplified to a discontinuous plane strain theory model. The modeling results show that it is completely possible for continental crust to be subducted to a depth of 120 km under certain circumstances and conditions. At the same time, the simulations of continental subduction under a single dynamical factor have also been made, including the pull force of the subducted oceanic lithosphere, the drag force connected with mantle convection and the push force of the mid-ocean ridge. These experiments show that the drag force connected with mantle convection is critical for continent subduction.展开更多
Differences in the structure and semantics of knowledge that is created and maintained by the various actors on the World Wide Web make its exchange and utilization a problematic task. This is an important issue facin...Differences in the structure and semantics of knowledge that is created and maintained by the various actors on the World Wide Web make its exchange and utilization a problematic task. This is an important issue facing organizations undertaking knowledge management initiatives. An XML-based and ontology-supported knowledge description language (KDL) is presented, which has three-tier structure (core KDL, extended KDL and complex KDL), and takes advantages of strong point of ontology, XML, description logics, frame-based systems. And then, the framework and XML based syntax of KDL are introduced, and the methods of translating KDL into first order logic (FOL) are presented. At last, the implementation of KDL on the Web is described, and the reasoning ability of KDL proved by experiment is illustrated in detail.展开更多
文摘Continent subduction is one of the hot research problems in geoscience. New models presented here have been set up and two-dimensional numerical modeling research on the possibility of continental subduction has been made with the finite element software, ANSYS, based on documentary evidence and reasonable assumptions that the subduction of oceanic crust has occurred, the subduction of continental crust can take place and the process can be simplified to a discontinuous plane strain theory model. The modeling results show that it is completely possible for continental crust to be subducted to a depth of 120 km under certain circumstances and conditions. At the same time, the simulations of continental subduction under a single dynamical factor have also been made, including the pull force of the subducted oceanic lithosphere, the drag force connected with mantle convection and the push force of the mid-ocean ridge. These experiments show that the drag force connected with mantle convection is critical for continent subduction.
文摘Differences in the structure and semantics of knowledge that is created and maintained by the various actors on the World Wide Web make its exchange and utilization a problematic task. This is an important issue facing organizations undertaking knowledge management initiatives. An XML-based and ontology-supported knowledge description language (KDL) is presented, which has three-tier structure (core KDL, extended KDL and complex KDL), and takes advantages of strong point of ontology, XML, description logics, frame-based systems. And then, the framework and XML based syntax of KDL are introduced, and the methods of translating KDL into first order logic (FOL) are presented. At last, the implementation of KDL on the Web is described, and the reasoning ability of KDL proved by experiment is illustrated in detail.
