Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary...Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary with plant species.Therefore,we hypothesized that hydrological fluctuation changes effects of species richness on productivity of wetland plant communities.Methods We constructed wetland plant communities consisting of three or six wetland plant species and subjected them to hydrological fluctuation(i.e.gradually changing water level)of two frequencies and two ranges,with unchanged water level as the control.We measured height,root and shoot dry mass of each plant at harvest.Important Findings Hydrological fluctuation significantly decreased biomass of wetland plant communities,which was due to impacts of fluctuation range,but not those of fluctuation frequency.Community biomass was significantly higher when species richness was higher,and such an effect did not depend on hydrological fluctuation.Therefore,hydrological fluctuation can decrease the productivity of wetland plant communities but may not alter the diversity-productivity relationship.展开更多
The similarity criterion for water flooding reservoir flows is concerned with in the present paper. When finding out all the dimensionless variables governing this kind of flow, their physical meanings are subsequentl...The similarity criterion for water flooding reservoir flows is concerned with in the present paper. When finding out all the dimensionless variables governing this kind of flow, their physical meanings are subsequently elucidated. Then, a numerical approach of sensitivity analysis is adopted to quantify their corresponding dominance degree among the similarity parameters. In this way, we may finally identify major scaling law in different parameter range and demonstrate the respective effects of viscosity, permeability and injection rate.展开更多
Ad Hoc网络DSR路由协议因采用泛洪机制导致较高路由开销,提出一种有约束的局部化查询优化方案,称为LDSR协议。在原有DSR协议基础上,以小世界理论确定局部化查询跳数上限,以移动网络保持连通的临界传输半径和移动节点的最大移动速度确定...Ad Hoc网络DSR路由协议因采用泛洪机制导致较高路由开销,提出一种有约束的局部化查询优化方案,称为LDSR协议。在原有DSR协议基础上,以小世界理论确定局部化查询跳数上限,以移动网络保持连通的临界传输半径和移动节点的最大移动速度确定路由有效时间,在两个约束条件下LDSR协议利用动态选择机制实现局部化查询,形成局部泛洪。仿真表明,LDSR协议在路由负载较大和网络移动性较高的情况下可以大大减小路由开销和平均端到端时延,而分组成功传送率损失很小。展开更多
基金Fundamental Research Funds for the Central Universities(TD-JC-2013-1)Specialized Research Fund for the Doctoral Program of Higher Education(20120014120001)National Natural Science Foundation of China(31200314,31470475).
文摘Aims The diversity-productivity relationship is one of the most critical questions in ecology and can be altered by environmental factors.Hydrological fluctuation affects growth of wetland plants,and such effects vary with plant species.Therefore,we hypothesized that hydrological fluctuation changes effects of species richness on productivity of wetland plant communities.Methods We constructed wetland plant communities consisting of three or six wetland plant species and subjected them to hydrological fluctuation(i.e.gradually changing water level)of two frequencies and two ranges,with unchanged water level as the control.We measured height,root and shoot dry mass of each plant at harvest.Important Findings Hydrological fluctuation significantly decreased biomass of wetland plant communities,which was due to impacts of fluctuation range,but not those of fluctuation frequency.Community biomass was significantly higher when species richness was higher,and such an effect did not depend on hydrological fluctuation.Therefore,hydrological fluctuation can decrease the productivity of wetland plant communities but may not alter the diversity-productivity relationship.
基金The project supported by the Innovative Project of CAS (KJCX-SW-L08)the National Basic Research Program of China(973)
文摘The similarity criterion for water flooding reservoir flows is concerned with in the present paper. When finding out all the dimensionless variables governing this kind of flow, their physical meanings are subsequently elucidated. Then, a numerical approach of sensitivity analysis is adopted to quantify their corresponding dominance degree among the similarity parameters. In this way, we may finally identify major scaling law in different parameter range and demonstrate the respective effects of viscosity, permeability and injection rate.
