The dam of Three Gorges Project is a concrete gravity dam with the crest elevation of 185 m,the maximum height of 181 m and dam axis length of 2 309.5 m.The dam consists of spillway,powerhouse,non-over flow,ship-lift,...The dam of Three Gorges Project is a concrete gravity dam with the crest elevation of 185 m,the maximum height of 181 m and dam axis length of 2 309.5 m.The dam consists of spillway,powerhouse,non-over flow,ship-lift,temporary ship-lock,left diversion wall and longitudinal cofferdam blocks.Some key techniques relating to dam structure design are presented,including hydraulics of flood discharge structure,dam joint design,layout and structural type of penstock,deep anti-sliding stability of dam foundation,reconstruction of temporary ship-lock and closed drainage and pumping of dam foundation.展开更多
The dam of Three Gorges Project is characterized by large flood discharge capacity,more outlets,complicated flood discharge and energy dissipation structure,and the stability of the bank powerhouse dam foundation is e...The dam of Three Gorges Project is characterized by large flood discharge capacity,more outlets,complicated flood discharge and energy dissipation structure,and the stability of the bank powerhouse dam foundation is endangered by large gentle-dip structural plane of the bedrock due to the deep excavation of powerhouse at the dam-toe.For the dam body concrete,the durability requirement is high and the temperature control and crack prevention are difficult.The practical experience which could be used for reference in the design and construction of asphalt concrete core wall for Maopingxi protective earth-rock dam is scarce.The power station operates with high water head and large head variation.The type selection of penstock and intake as well as the embedding way of spiral case are complicated in technique,and the tailrace tunnel with sloping ceiling of underground power plant is arranged instead of traditional tailrace surge tank.For the double-line five-step ship-lock,the design of fully lined ship-lock,high head delivery system and large-sized miter gates and hoists is very challenging due to high operation head,complicated delivery conditions and building in deep excavated rock.The preferred solutions,optimal schemes and technical measures for various structures,as well as the innovation achievements proved by practice are highlighted.展开更多
The fabrication of functional microcarriers capable of achieving in vivo-like three-dimensional cell culture is important for many tissue engineering applications. Here,inspired by the structure of Buddha beads, which...The fabrication of functional microcarriers capable of achieving in vivo-like three-dimensional cell culture is important for many tissue engineering applications. Here,inspired by the structure of Buddha beads, which are generally composed of moveable beads strung on a rope, we present novel cell microcarriers with controllable macropores and heterogeneous microstructures by using a capillary array microfluidic technology. Microfibers with a string of moveable and releasable microcarriers could be achieved by an immediate gelation reaction of sodium alginate spinning and subsequent polymerization of cell-dispersed gelatin methacrylate emulsification. The sizes of the microcarriers and their inner macropores could be well tailored by adjusting the flow rates of the microfluidic phases; this was of great importance in guaranteeing a sufficient supply of nutrients during cell culture. In addition, by infusing multiple cell-dispersed pregel solutions into the capillaries, the microcarriers with spatially heterogeneous cell encapsulations for mimicking physiological structures and functions could also be achieved.展开更多
文摘The dam of Three Gorges Project is a concrete gravity dam with the crest elevation of 185 m,the maximum height of 181 m and dam axis length of 2 309.5 m.The dam consists of spillway,powerhouse,non-over flow,ship-lift,temporary ship-lock,left diversion wall and longitudinal cofferdam blocks.Some key techniques relating to dam structure design are presented,including hydraulics of flood discharge structure,dam joint design,layout and structural type of penstock,deep anti-sliding stability of dam foundation,reconstruction of temporary ship-lock and closed drainage and pumping of dam foundation.
文摘The dam of Three Gorges Project is characterized by large flood discharge capacity,more outlets,complicated flood discharge and energy dissipation structure,and the stability of the bank powerhouse dam foundation is endangered by large gentle-dip structural plane of the bedrock due to the deep excavation of powerhouse at the dam-toe.For the dam body concrete,the durability requirement is high and the temperature control and crack prevention are difficult.The practical experience which could be used for reference in the design and construction of asphalt concrete core wall for Maopingxi protective earth-rock dam is scarce.The power station operates with high water head and large head variation.The type selection of penstock and intake as well as the embedding way of spiral case are complicated in technique,and the tailrace tunnel with sloping ceiling of underground power plant is arranged instead of traditional tailrace surge tank.For the double-line five-step ship-lock,the design of fully lined ship-lock,high head delivery system and large-sized miter gates and hoists is very challenging due to high operation head,complicated delivery conditions and building in deep excavated rock.The preferred solutions,optimal schemes and technical measures for various structures,as well as the innovation achievements proved by practice are highlighted.
基金supported by the National Natural Science Foundation of China(21473029 and 51522302)the NSAF Foundation of China(U1530260)+3 种基金the Natural Science Foundation of Jiangsu(BK20140028)the Program for New Century Excellent Talents in Universitythe Scientific Research Foundation of Southeast Universitythe Scientific Research Foundation of Graduate School of Southeast University
文摘The fabrication of functional microcarriers capable of achieving in vivo-like three-dimensional cell culture is important for many tissue engineering applications. Here,inspired by the structure of Buddha beads, which are generally composed of moveable beads strung on a rope, we present novel cell microcarriers with controllable macropores and heterogeneous microstructures by using a capillary array microfluidic technology. Microfibers with a string of moveable and releasable microcarriers could be achieved by an immediate gelation reaction of sodium alginate spinning and subsequent polymerization of cell-dispersed gelatin methacrylate emulsification. The sizes of the microcarriers and their inner macropores could be well tailored by adjusting the flow rates of the microfluidic phases; this was of great importance in guaranteeing a sufficient supply of nutrients during cell culture. In addition, by infusing multiple cell-dispersed pregel solutions into the capillaries, the microcarriers with spatially heterogeneous cell encapsulations for mimicking physiological structures and functions could also be achieved.
