We consider an electrostatic bow and arrow both charged positively. The bow is circular and horizontal the massive arrow is vertically aligned with the bow’s symmetry axis with its head up. The arrow is released free...We consider an electrostatic bow and arrow both charged positively. The bow is circular and horizontal the massive arrow is vertically aligned with the bow’s symmetry axis with its head up. The arrow is released freely, the electrically charged ring repels the arrow and the gravity slows its uprise. The mass, length, and charge of the arrow as well as the size of the ring and its charge adjusted making the arrow oscillate up and down. The kinematic and dynamic quantities of the oscillations are calculated, and the relevant phase diagrams are depicted. In pursuing these goals, a Computer Algebra System (CAS) specifically Mathematica [1] is used. Among various scenarios, the case of a charged ring and a point charge is discussed.展开更多
Congenitally malformed aortic valves are more susceptible to valve injury due to rheumatic fever, mechanical stress of altered flow patterns, atherosclerotic risk factors and degenerative changes. Rheumatic involvemen...Congenitally malformed aortic valves are more susceptible to valve injury due to rheumatic fever, mechanical stress of altered flow patterns, atherosclerotic risk factors and degenerative changes. Rheumatic involvement usually occurs in childhood and it is progressive leading to diffuse thickening and fibrosis at leaflet edges and thus differentiated from other patterns of valve damage. Background of this case report revealed the bicuspid nature of the aortic valve due to rheumatic commissural fusion and analysis of echocardiographic parameters in combined lesions of both aortic and mitral valves with severe LV (left ventricular) dysfunction. Left ventricular (LV) and left atrial (LA) dilations predisposing to the formation of smoke (SEC-spontaneous echo contrast) in LV and LA as a consequence of mitral and aortic valve disease are illustrated by 2D echocardiographic imaging in this 41-year-old male.展开更多
文摘We consider an electrostatic bow and arrow both charged positively. The bow is circular and horizontal the massive arrow is vertically aligned with the bow’s symmetry axis with its head up. The arrow is released freely, the electrically charged ring repels the arrow and the gravity slows its uprise. The mass, length, and charge of the arrow as well as the size of the ring and its charge adjusted making the arrow oscillate up and down. The kinematic and dynamic quantities of the oscillations are calculated, and the relevant phase diagrams are depicted. In pursuing these goals, a Computer Algebra System (CAS) specifically Mathematica [1] is used. Among various scenarios, the case of a charged ring and a point charge is discussed.
文摘Congenitally malformed aortic valves are more susceptible to valve injury due to rheumatic fever, mechanical stress of altered flow patterns, atherosclerotic risk factors and degenerative changes. Rheumatic involvement usually occurs in childhood and it is progressive leading to diffuse thickening and fibrosis at leaflet edges and thus differentiated from other patterns of valve damage. Background of this case report revealed the bicuspid nature of the aortic valve due to rheumatic commissural fusion and analysis of echocardiographic parameters in combined lesions of both aortic and mitral valves with severe LV (left ventricular) dysfunction. Left ventricular (LV) and left atrial (LA) dilations predisposing to the formation of smoke (SEC-spontaneous echo contrast) in LV and LA as a consequence of mitral and aortic valve disease are illustrated by 2D echocardiographic imaging in this 41-year-old male.
