The paper summarizes the research status on biological risks of agricultural GM laboratory and the risk factors of bio-safety in GM crops laboratory,and then proposes corresponding safety management suggestions.
The paper discusses several wide-spread misunderstandings of Kuhn＇s theory of scientific development, most prominently the ascription that he conceives of scientific development as irrational. The core of this ascrip...The paper discusses several wide-spread misunderstandings of Kuhn＇s theory of scientific development, most prominently the ascription that he conceives of scientific development as irrational. The core of this ascription is an assessment of incommensurability as implying the lack of any rational possibility of theory comparison. This is supposed to be due to Gestalt switches and a quasi-religious element of conversion in theory change. Accordingly, scientific revolutions cannot be a serious matter for philosophical analysis; they furthermore foreclose any scientific progress. It is shown that such images of Kuhn＇s theory rest on deep misunderstandings that are partly due to Kuhn＇s writing style.展开更多
Ocean platforms are subjected to a variety of environment loads, such as those from winds, waves, currents, etc. In this study, the torsion problems of a gravity platform column with cracks under wind load were invest...Ocean platforms are subjected to a variety of environment loads, such as those from winds, waves, currents, etc. In this study, the torsion problems of a gravity platform column with cracks under wind load were investigated. The colmnn was assumed to be a composite cylinder. Therefore the torsion fracture problem of a composite cylinder was considered, and new boundary integral equations for the Saint-Venant torsion problem of a composite cylinder with curvilinear cracks were derived. The problem was re- duced to solving the boundary integral equations on every boundary. By using the new boundary element method, the torsion prob- lem of the gravity platform colunm with a straight crack under various wind loads was calculated. The obtained results were com- pared with those obtained for a torsion problem of the same column without cracks to prove the applicability of the present method. The comparison showed that the detrimental effect of cracks in a column should be considered in marine engineering.展开更多
This serial research proposes the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit,to provide the constant output for the grid system,even at the suddenly fluctuating/t...This serial research proposes the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit,to provide the constant output for the grid system,even at the suddenly fluctuating/turbulent wind.In this paper,the tandem impellers of the counter-rotating type pumping unit was operated at the turbine mode,and the performances and the flow conditions were investigated numerically and experimentally.The 3-D turbulent flows in the runners were simulated at the steady state condition by using the commercial CFD code of ANSYS-CFX ver.12 with the SST turbulence model.While providing the pump unit for the turbine mode,the maximum hydraulic efficiency is close to one of the counter-rotating type hydroelectric unit designed exclu-sively for the turbine mode.Besides,the runner/impeller of the unit works evidently so as to coincide the angularmomentum change through the front runners/impellers with that through the rear runners/impellers,namely to take the axial flow at not only the inlet but also the outlet without the guide vanes.These results show that this type of unit is effective to work at not only the pumping but also the turbine modes.展开更多
基金Supported by the National Basic Research Program of China(973Program)(2010CB126100)Fundamental Research Funds forthe Central Universities~~
文摘The paper summarizes the research status on biological risks of agricultural GM laboratory and the risk factors of bio-safety in GM crops laboratory,and then proposes corresponding safety management suggestions.
文摘The paper discusses several wide-spread misunderstandings of Kuhn＇s theory of scientific development, most prominently the ascription that he conceives of scientific development as irrational. The core of this ascription is an assessment of incommensurability as implying the lack of any rational possibility of theory comparison. This is supposed to be due to Gestalt switches and a quasi-religious element of conversion in theory change. Accordingly, scientific revolutions cannot be a serious matter for philosophical analysis; they furthermore foreclose any scientific progress. It is shown that such images of Kuhn＇s theory rest on deep misunderstandings that are partly due to Kuhn＇s writing style.
基金supported by the National High-Technology Research and Development Program of China (No.2007AA09Z317)
文摘Ocean platforms are subjected to a variety of environment loads, such as those from winds, waves, currents, etc. In this study, the torsion problems of a gravity platform column with cracks under wind load were investigated. The colmnn was assumed to be a composite cylinder. Therefore the torsion fracture problem of a composite cylinder was considered, and new boundary integral equations for the Saint-Venant torsion problem of a composite cylinder with curvilinear cracks were derived. The problem was re- duced to solving the boundary integral equations on every boundary. By using the new boundary element method, the torsion prob- lem of the gravity platform colunm with a straight crack under various wind loads was calculated. The obtained results were com- pared with those obtained for a torsion problem of the same column without cracks to prove the applicability of the present method. The comparison showed that the detrimental effect of cracks in a column should be considered in marine engineering.
基金co-sponsored by Japan Society for the Promotion of Science KAKENHI23860035
文摘This serial research proposes the hybrid power system combined the wind power unit with the counter-rotating type pump-turbine unit,to provide the constant output for the grid system,even at the suddenly fluctuating/turbulent wind.In this paper,the tandem impellers of the counter-rotating type pumping unit was operated at the turbine mode,and the performances and the flow conditions were investigated numerically and experimentally.The 3-D turbulent flows in the runners were simulated at the steady state condition by using the commercial CFD code of ANSYS-CFX ver.12 with the SST turbulence model.While providing the pump unit for the turbine mode,the maximum hydraulic efficiency is close to one of the counter-rotating type hydroelectric unit designed exclu-sively for the turbine mode.Besides,the runner/impeller of the unit works evidently so as to coincide the angularmomentum change through the front runners/impellers with that through the rear runners/impellers,namely to take the axial flow at not only the inlet but also the outlet without the guide vanes.These results show that this type of unit is effective to work at not only the pumping but also the turbine modes.
