In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a wat...In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a water model for pursuing better bubble disintegration and dispersion.Effects of various factors on bubble disintegration and dispersion were investigated.These factors were stirring mode,eccentricity and rotation speed,nozzle structure,nozzle immersion depth,and gas flow rate.Gas injection from a nozzle at the end of the impeller shaft and from an immersed lance was studied.Under eccentric stirring,a vortex was formed away from the shaft.Small bubbles were produced in the strong turbulence or high shear stress field near the rotating impeller and moved in the direction to the vortex keeping up with the macroscopic flow induced by the mechanical stirring.Thus small bubbles could disperse widely in the bath under eccentric stirring with unidirectional rotation.展开更多
Sports competition is competition in a particular environment, mad it has its own characteristics, tasks, opponents, environment and methods. Despite the psychological training is relevant to, and associated with phys...Sports competition is competition in a particular environment, mad it has its own characteristics, tasks, opponents, environment and methods. Despite the psychological training is relevant to, and associated with physical exercise, but its nature determines its specificity. On the psychological point of view, due to the reinforcement of external stimuli, which led to strong psychological pressure, these are manifested through the behaviors of the players when they are compete with others, such as fear, excessive psychological tension, incorrect competition motivation, ambiguous purpose, lack of confidence, even there are phenomenon like isolated characteristics and irritation, etc. Thus, the regulation and control of mental activity, the overcome of the psychological barriers, and the implementation of the psychology training have become a big question which teachers and coaches must pay attention to and need to be solved.展开更多
基金Projects (50974035,51074047) supported by the National Natural Science Foundation of ChinaProject (20090407) supported by the Doctoral Fund of Ministry of Education,ChinaProject (200921007) supported by Liaoning Key Science and Technology,China
文摘In gas injection refining processes,wide dispersion of small bubbles in the bath is indispensable for high refining efficiency.Eccentric mechanical stirring with unidirectional impeller rotation was tested using a water model for pursuing better bubble disintegration and dispersion.Effects of various factors on bubble disintegration and dispersion were investigated.These factors were stirring mode,eccentricity and rotation speed,nozzle structure,nozzle immersion depth,and gas flow rate.Gas injection from a nozzle at the end of the impeller shaft and from an immersed lance was studied.Under eccentric stirring,a vortex was formed away from the shaft.Small bubbles were produced in the strong turbulence or high shear stress field near the rotating impeller and moved in the direction to the vortex keeping up with the macroscopic flow induced by the mechanical stirring.Thus small bubbles could disperse widely in the bath under eccentric stirring with unidirectional rotation.
文摘Sports competition is competition in a particular environment, mad it has its own characteristics, tasks, opponents, environment and methods. Despite the psychological training is relevant to, and associated with physical exercise, but its nature determines its specificity. On the psychological point of view, due to the reinforcement of external stimuli, which led to strong psychological pressure, these are manifested through the behaviors of the players when they are compete with others, such as fear, excessive psychological tension, incorrect competition motivation, ambiguous purpose, lack of confidence, even there are phenomenon like isolated characteristics and irritation, etc. Thus, the regulation and control of mental activity, the overcome of the psychological barriers, and the implementation of the psychology training have become a big question which teachers and coaches must pay attention to and need to be solved.
