In physics,the Klein-Gordon equation describes the motion of a quantum scalar or pseudoscalar field.Itis important to find actual values of its solutions in general timespace manifold.The paper deals with description ...In physics,the Klein-Gordon equation describes the motion of a quantum scalar or pseudoscalar field.Itis important to find actual values of its solutions in general timespace manifold.The paper deals with description ofdiscrete exterior calculus method for solving this equation numerically on space manifold and the time.The analysis ofstable condition and error for this method is also accomplished.展开更多
The study of animal personality has attracted considerable attention, as it has revealed a number of similarities in personality between humans and several nonhuman species. At the same time the adaptive value and evo...The study of animal personality has attracted considerable attention, as it has revealed a number of similarities in personality between humans and several nonhuman species. At the same time the adaptive value and evolutionary maintenance of different personalities are the subject of debate. Since Pavlov＇s work on dogs, students of comparative cognition have been aware that animals display vast individual differences on cognitive tasks, and that these differences may not be entirely accounted for differences in cognitive abilities. Here, we argue that personality is an important source of variation that may affect cognitive performance and we hypothesise mutual influences between personality and cognition across an individual＇s lifespan. In particular, we suggest that： 1） personality profiles may be markers of different cognitive styles; 2） success or failure in cognitive tasks could affect different personalities differently; 3） ontogenetic changes of personality profiles could be reflected in changes in cognitive performance. The study of such interplay has implications in animal welfare as well as in neuroscience and in translational medicine [Current Zoology 57 （4）： 491-498, 2011].展开更多
The assembling error may lead to variation in stagger angles,which would affect the aerodynamic performance of the turbine.To investigate this underlying effect,two parallel numerical experiments on two turbines with ...The assembling error may lead to variation in stagger angles,which would affect the aerodynamic performance of the turbine.To investigate this underlying effect,two parallel numerical experiments on two turbines with the same profile,but uniform and nonuniform vane stagger angle respectively,were conducted in both steady and unsteady methods.The results indicate that certain changes in the detailed flow field of the turbine occur when the stagger angles are nonuniform,further,the blade loading distribution of the vane and rotor become markedly different from that in uniform vane stagger angle situation.Then these consequences caused by nonuniformity mentioned above enhance the unsteadiness of the flow,finally,the aerodynamic performance changes dramatically.It also shows that,compared with steady simulation,the unsteady numerical simulation is necessary in this investigation.展开更多
The authors establish error estimates for recently developed finite-element methods for incompressible viscous flow in domains with no-slip boundary conditions.The methods arise by discretization of a well-posed exten...The authors establish error estimates for recently developed finite-element methods for incompressible viscous flow in domains with no-slip boundary conditions.The methods arise by discretization of a well-posed extended Navier-Stokes dynamics for which pressure is determined from current velocity and force fields.The methods use C1 elements for velocity and C0 elements for pressure.A stability estimate is proved for a related finite-element projection method close to classical time-splitting methods of Orszag,Israeli,DeVille and Karniadakis.展开更多
基金Supported by China Postdoctoral Science Foundation under Grant No.20090460102 Zhejiang Province Postdoctoral Science Foundation,National Key Basic Research Program of China under Grant No.2004CB318000 National Natural Science Foundation of China under Grant No.10871170
文摘In physics,the Klein-Gordon equation describes the motion of a quantum scalar or pseudoscalar field.Itis important to find actual values of its solutions in general timespace manifold.The paper deals with description ofdiscrete exterior calculus method for solving this equation numerically on space manifold and the time.The analysis ofstable condition and error for this method is also accomplished.
文摘The study of animal personality has attracted considerable attention, as it has revealed a number of similarities in personality between humans and several nonhuman species. At the same time the adaptive value and evolutionary maintenance of different personalities are the subject of debate. Since Pavlov＇s work on dogs, students of comparative cognition have been aware that animals display vast individual differences on cognitive tasks, and that these differences may not be entirely accounted for differences in cognitive abilities. Here, we argue that personality is an important source of variation that may affect cognitive performance and we hypothesise mutual influences between personality and cognition across an individual＇s lifespan. In particular, we suggest that： 1） personality profiles may be markers of different cognitive styles; 2） success or failure in cognitive tasks could affect different personalities differently; 3） ontogenetic changes of personality profiles could be reflected in changes in cognitive performance. The study of such interplay has implications in animal welfare as well as in neuroscience and in translational medicine [Current Zoology 57 （4）： 491-498, 2011].
基金supported by National Nature Science Foundation of China under Grant Number 50776003the Innovation Foundation of BUAA for PhD Graduates
文摘The assembling error may lead to variation in stagger angles,which would affect the aerodynamic performance of the turbine.To investigate this underlying effect,two parallel numerical experiments on two turbines with the same profile,but uniform and nonuniform vane stagger angle respectively,were conducted in both steady and unsteady methods.The results indicate that certain changes in the detailed flow field of the turbine occur when the stagger angles are nonuniform,further,the blade loading distribution of the vane and rotor become markedly different from that in uniform vane stagger angle situation.Then these consequences caused by nonuniformity mentioned above enhance the unsteadiness of the flow,finally,the aerodynamic performance changes dramatically.It also shows that,compared with steady simulation,the unsteady numerical simulation is necessary in this investigation.
基金Project supported by the National Science Foundation (Nos.DMS 06-04420 (RLP),DMS 08-11177(JGL))the Center for Nonlinear Analysis (CNA) under National Science Foundation Grant (Nos.0405343,0635983)
文摘The authors establish error estimates for recently developed finite-element methods for incompressible viscous flow in domains with no-slip boundary conditions.The methods arise by discretization of a well-posed extended Navier-Stokes dynamics for which pressure is determined from current velocity and force fields.The methods use C1 elements for velocity and C0 elements for pressure.A stability estimate is proved for a related finite-element projection method close to classical time-splitting methods of Orszag,Israeli,DeVille and Karniadakis.
