Background:Mitral valve perforation refers to the occurrence of cracks or openings in the structure of the mitral valve,allowing blood to escape through these gaps.Typically,this is caused by infective endocarditis an...Background:Mitral valve perforation refers to the occurrence of cracks or openings in the structure of the mitral valve,allowing blood to escape through these gaps.Typically,this is caused by infective endocarditis and the most common site is the anterior leaflet.However,it is crucial to explore other potential causes of valve damage,particularly when conventional risk factors are not apparent.Case presentation:We present a case of a middle-aged male patient who developed mitral valve perforation because of aortic valve regurgitation in the absence of infective endocarditis.Conclusion:Exploring such rare cases contributes to a deeper understanding of valvular diseases and enhances clinical decision making for effective management.展开更多
In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the...In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.展开更多
文摘Background:Mitral valve perforation refers to the occurrence of cracks or openings in the structure of the mitral valve,allowing blood to escape through these gaps.Typically,this is caused by infective endocarditis and the most common site is the anterior leaflet.However,it is crucial to explore other potential causes of valve damage,particularly when conventional risk factors are not apparent.Case presentation:We present a case of a middle-aged male patient who developed mitral valve perforation because of aortic valve regurgitation in the absence of infective endocarditis.Conclusion:Exploring such rare cases contributes to a deeper understanding of valvular diseases and enhances clinical decision making for effective management.
基金supported by the ‘‘111" Project of China (No. B17037)
文摘In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.
