Persistent ductus arteriosus （PDA） is a congenital cardiovascular malformation connecting the pulmonary trunk of the proximal left pulmonary artery and the descending aorta distal to the left subclavian artery. Norm...Persistent ductus arteriosus （PDA） is a congenital cardiovascular malformation connecting the pulmonary trunk of the proximal left pulmonary artery and the descending aorta distal to the left subclavian artery. Normally, the duct closes after birth as a result of a sudden increase in arterial oxygen saturation and a decrease in the level of vasoaetive prostaglandins. The incidence of persistent ductus arteriosus accounts for approximately 10% of all congenital heart diseases.展开更多
Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m.The steel box girder of main span includes five portions:back span large unit,large block of pylon,standard girder,back span cl...Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m.The steel box girder of main span includes five portions:back span large unit,large block of pylon,standard girder,back span closure girder and middle span closure girder.Each back span large unit is fabricated by welding several deck segments together in factory,and is erected by floating crane.As navigational clearance of the main bridge is high,the traditional truss lifting device can't satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight.Hence,a kind of lighter lifting device for the erection of back span large units was accepted for this bridge.In this paper,the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method.Because the bridge's navigation clearance is high,and the girder segment is wide and heavy,the meteorology and hydrology condition of the bridge district is abominable,and the requirements of long cable girder side pull-in,structure and performance propose high request to the lifting gantry.In this paper,the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.展开更多
文摘Persistent ductus arteriosus （PDA） is a congenital cardiovascular malformation connecting the pulmonary trunk of the proximal left pulmonary artery and the descending aorta distal to the left subclavian artery. Normally, the duct closes after birth as a result of a sudden increase in arterial oxygen saturation and a decrease in the level of vasoaetive prostaglandins. The incidence of persistent ductus arteriosus accounts for approximately 10% of all congenital heart diseases.
基金National Science and Technology Support Program of China(No.2006BAG04B0)
文摘Sutong Bridge is a cable-stayed bridge with a steel box girder and a main span of 1 088 m.The steel box girder of main span includes five portions:back span large unit,large block of pylon,standard girder,back span closure girder and middle span closure girder.Each back span large unit is fabricated by welding several deck segments together in factory,and is erected by floating crane.As navigational clearance of the main bridge is high,the traditional truss lifting device can't satisfy the requirement of domestic lifting cranes for this kind of lifting height and weight.Hence,a kind of lighter lifting device for the erection of back span large units was accepted for this bridge.In this paper,the design and use of this lifting device is introduced.The upper structure used lifting gantry to install the standard girder segment by cantilever method.Because the bridge's navigation clearance is high,and the girder segment is wide and heavy,the meteorology and hydrology condition of the bridge district is abominable,and the requirements of long cable girder side pull-in,structure and performance propose high request to the lifting gantry.In this paper,the design and use key point of long cable pull-in angle adjustment device integrate into lifting gantry is introduced.
