Scientists and policy-makers are now well aware of the ecological and societal problems associated with the introduction of species by humans across natural barriers to dispersal. Some introduced species spread abunda...Scientists and policy-makers are now well aware of the ecological and societal problems associated with the introduction of species by humans across natural barriers to dispersal. Some introduced species spread abundantly in their new habitats and have negative effects on existing species, both agricultural and natural. Such introduced, invasive species can alter fire, nutrient, and hydrological regimes and have large economic costs.展开更多
Road tunnel excavation often traverses coal strata, which is at risk of firedamp explosion that usually results in disaster. Airtight concrete grouting is popularly used in this kind of tunnel project. Based on the es...Road tunnel excavation often traverses coal strata, which is at risk of firedamp explosion that usually results in disaster. Airtight concrete grouting is popularly used in this kind of tunnel project. Based on the essential theory of mechanics of fluids in porous media, the principle of improving concrete airtight property and its influential factors are investigated. The proportioning tests and monitoring method for airtight concrete are introduced, which is illustrated by a case study applied to the project of the Huayinshan Tunnel. It is proved by engineering practices that the achievement of this research work is beneficial to tunneling project across coal strata.展开更多
This paper describes a new method which has been developed for the solution of direct and inverse problems of 3-D compressible flows in turbomachinery.Two types of streamfunctions are propsed in the paper and the atre...This paper describes a new method which has been developed for the solution of direct and inverse problems of 3-D compressible flows in turbomachinery.Two types of streamfunctions are propsed in the paper and the atreamfunction-coordinate system is applied in numerical computations,The algorithm is applied to statorblades and the results are compared with experimental data.It is thown that the comparisons are very satisfactory.展开更多
文摘Scientists and policy-makers are now well aware of the ecological and societal problems associated with the introduction of species by humans across natural barriers to dispersal. Some introduced species spread abundantly in their new habitats and have negative effects on existing species, both agricultural and natural. Such introduced, invasive species can alter fire, nutrient, and hydrological regimes and have large economic costs.
基金Funded by the Doctoral Foundation of the Ministry of Education of China (2000061115)
文摘Road tunnel excavation often traverses coal strata, which is at risk of firedamp explosion that usually results in disaster. Airtight concrete grouting is popularly used in this kind of tunnel project. Based on the essential theory of mechanics of fluids in porous media, the principle of improving concrete airtight property and its influential factors are investigated. The proportioning tests and monitoring method for airtight concrete are introduced, which is illustrated by a case study applied to the project of the Huayinshan Tunnel. It is proved by engineering practices that the achievement of this research work is beneficial to tunneling project across coal strata.
基金Project supported by the National Natural Science Fundation of China
文摘This paper describes a new method which has been developed for the solution of direct and inverse problems of 3-D compressible flows in turbomachinery.Two types of streamfunctions are propsed in the paper and the atreamfunction-coordinate system is applied in numerical computations,The algorithm is applied to statorblades and the results are compared with experimental data.It is thown that the comparisons are very satisfactory.
