Based on the laws of momentum conservation and impulse in accelerating process, the distribution on speed of ununiform slurry flow in a horizontal pipe was studied. According to the momentum change of solid particles ...Based on the laws of momentum conservation and impulse in accelerating process, the distribution on speed of ununiform slurry flow in a horizontal pipe was studied. According to the momentum change of solid particles and conveying liquid of slurry flow during accelerating, and some effect factors, the relationship between the speed of solid particles and the speed of conveying liquid was obtained. When dealing with the friction between sliding solid particles and pipe, it is pivotal to reasonably distribute component of friction to each solid particle. The friction coefficient between solid particles was obtained by forces analysis and theoretic calculation, and can be used to calculate the friction force on every solid particle. The effect of friction on speed of every solid particle was investigated through the impulse law. The result is more accurate than that by using uniform friction on solid particles. It is completely new method to use above theory to get solid particles speed distribution, conveying liquid speed distribution and slurry speed distribution.展开更多
This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal D...This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal Data Structure),the Local Constrained Delaunay Triangulations and semantic hierarchy.The adjacent relation among connected objects and unconnected objects has been studied through constrained triangle as elementary processing unit in aggregation operation.The hierarchical semantic analytical matrix is given for analyzing the similarity between objects types and between objects.Several different cases of aggregation have been presented in this paper.展开更多
In order to understand the impact of land tenure change on the land use after the Responsibility System was carried out after the 3rd Plenary Session of the 11th CPC Central Committee, 147 households in 6 villages, be...In order to understand the impact of land tenure change on the land use after the Responsibility System was carried out after the 3rd Plenary Session of the 11th CPC Central Committee, 147 households in 6 villages, belonging Xiangtan County and Zhuzhou County in Hunan Province, were selected as research samples, and the methods of interviewing and questionnaire surveying and secondary data analyzing were used. The results show that after having got the tenure of paddies, the farmers could determine the management projects according to the market demands, which caused the diversity of cultivated crop species and improved the efficient of land use. For the forestland, after having gotten the tenure of forestland, the farmers could adjust the structure of forest types and managed bamboo and orchards to get more earnings or they gave up managing forests and changed them into other projects. But that made the stability of agricultural ecological system unsteady because the forests were damaged seriously. After the tenure of land was separated from the ownership of land, the farmers who had the tenure of land could deal with the tenure of land according to laws and policies, and that caused the tenure of land to be rented-in and rented-out.展开更多
文摘Based on the laws of momentum conservation and impulse in accelerating process, the distribution on speed of ununiform slurry flow in a horizontal pipe was studied. According to the momentum change of solid particles and conveying liquid of slurry flow during accelerating, and some effect factors, the relationship between the speed of solid particles and the speed of conveying liquid was obtained. When dealing with the friction between sliding solid particles and pipe, it is pivotal to reasonably distribute component of friction to each solid particle. The friction coefficient between solid particles was obtained by forces analysis and theoretic calculation, and can be used to calculate the friction force on every solid particle. The effect of friction on speed of every solid particle was investigated through the impulse law. The result is more accurate than that by using uniform friction on solid particles. It is completely new method to use above theory to get solid particles speed distribution, conveying liquid speed distribution and slurry speed distribution.
文摘This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal Data Structure),the Local Constrained Delaunay Triangulations and semantic hierarchy.The adjacent relation among connected objects and unconnected objects has been studied through constrained triangle as elementary processing unit in aggregation operation.The hierarchical semantic analytical matrix is given for analyzing the similarity between objects types and between objects.Several different cases of aggregation have been presented in this paper.
文摘In order to understand the impact of land tenure change on the land use after the Responsibility System was carried out after the 3rd Plenary Session of the 11th CPC Central Committee, 147 households in 6 villages, belonging Xiangtan County and Zhuzhou County in Hunan Province, were selected as research samples, and the methods of interviewing and questionnaire surveying and secondary data analyzing were used. The results show that after having got the tenure of paddies, the farmers could determine the management projects according to the market demands, which caused the diversity of cultivated crop species and improved the efficient of land use. For the forestland, after having gotten the tenure of forestland, the farmers could adjust the structure of forest types and managed bamboo and orchards to get more earnings or they gave up managing forests and changed them into other projects. But that made the stability of agricultural ecological system unsteady because the forests were damaged seriously. After the tenure of land was separated from the ownership of land, the farmers who had the tenure of land could deal with the tenure of land according to laws and policies, and that caused the tenure of land to be rented-in and rented-out.
