The water mitigation effect on the propagation of shock wave was investigated numerically. The traditional smoothed particle hydrodynamics (SPH) method was modified based on Riemann solution. The comparison of numeric...The water mitigation effect on the propagation of shock wave was investigated numerically. The traditional smoothed particle hydrodynamics (SPH) method was modified based on Riemann solution. The comparison of numerical results with the analytical solution indicated that the modified SPH method has more advantages than the traditional SPH method. Using the modified SPH algorithm, a series of one-dimensional planar wave propagation problems were investigated, focusing on the influence of the air-gap between the high-pressure air and water and the thickness of water. The numerical results showed that water mitigation effect is significant. Up to 60% shock wave pressure reduction could be achieved with the existence of water, and the shape of shock wave was also changed greatly. It is seemly that the small air-gap between the high-pressure air and water has more influence on water mitigation effect.展开更多
We first establish a integral inequality for compact maximal space-like subman ifolds in pseudo-Riemannian manifolds Np(n+p). Then, we investigate compact space-like sub manifolds and hupersurfaces with parallel secon...We first establish a integral inequality for compact maximal space-like subman ifolds in pseudo-Riemannian manifolds Np(n+p). Then, we investigate compact space-like sub manifolds and hupersurfaces with parallel second fundamental form in Np(n+p) and some other ambient spaces. We obtain some distribution theorems for the square norm of the second fundamental form.展开更多
The conjugate of T-connection in a Riemannian manifold is obtained, also some of its properties are studied. T-statistical manifold is defined and was considered. Finally a characteristic vector field of the deformati...The conjugate of T-connection in a Riemannian manifold is obtained, also some of its properties are studied. T-statistical manifold is defined and was considered. Finally a characteristic vector field of the deformation algebra （M, , ） is also obtained.展开更多
This paper considers the existence problem of an elliptic equation, which is equivalent to the prescribing conformal Gaussian curvature problem on R^2. An existence result is proved. In particular, K（x） is allowed t...This paper considers the existence problem of an elliptic equation, which is equivalent to the prescribing conformal Gaussian curvature problem on R^2. An existence result is proved. In particular, K（x） is allowed to be unbounded above.展开更多
This paper considers the existence problem of an elliptic equation, which is equivalent to solving the so called prescribing conformal Gaussian curvature problem on the hyperbolic disc H^2. An existence result is prov...This paper considers the existence problem of an elliptic equation, which is equivalent to solving the so called prescribing conformal Gaussian curvature problem on the hyperbolic disc H^2. An existence result is proved. In particular, K（x） is allowed to be unbounded above.展开更多
in this paper,we prove that a complete n-dimensional Riemannian manifold with nonnegative kth-Ricci curvature, large volume growth has finite topological type provided that lim r→∞{（vol[B（p.r]/ωnrn-αM）rk（n-1...in this paper,we prove that a complete n-dimensional Riemannian manifold with nonnegative kth-Ricci curvature, large volume growth has finite topological type provided that lim r→∞{（vol[B（p.r]/ωnrn-αM）rk（n-1）/k＋1（1-α/2）}≤for some COllstant ε〉0 We also prove that a conlplete Riemannian manifold with nonnegative kth-Ricci curvature and undler some pinching conditions is diffeomorphic to R^n.展开更多
In this paper, we present Euler-Lagrange and Hamilton mechanical equations introduced on Riemann almost contact space of a Cartan space of order two. In the conclusion we discussed differential geometric and physical ...In this paper, we present Euler-Lagrange and Hamilton mechanical equations introduced on Riemann almost contact space of a Cartan space of order two. In the conclusion we discussed differential geometric and physical results about related mechanical equations.展开更多
在以色列犹太人大屠杀纪念馆＂国际义人园＂里,＂国际正义人士——何凤山先生纪念碑＂静静地沐浴着耶路撒冷的阳光,肃穆的石碑上醒目地镌刻着＂永远不能忘记的中国人＂。何凤山（1901年9月10日-1997年9月28日）,中国湖南人,中华民国外交...在以色列犹太人大屠杀纪念馆＂国际义人园＂里,＂国际正义人士——何凤山先生纪念碑＂静静地沐浴着耶路撒冷的阳光,肃穆的石碑上醒目地镌刻着＂永远不能忘记的中国人＂。何凤山（1901年9月10日-1997年9月28日）,中国湖南人,中华民国外交官,因在二战中拯救过数以千计的犹太人,而被誉为＂中国的辛德勒＂,2001年被以色列政府授予＂国际义人＂（RighteousAmong the Nations）称号。去世后才为世人所知1997年深秋,展开更多
基金Supported by National Natural Science Foundation of China(No.50638030 and 50525825)National Science and Technology Support Program(No.2006BAJ13B02)
文摘The water mitigation effect on the propagation of shock wave was investigated numerically. The traditional smoothed particle hydrodynamics (SPH) method was modified based on Riemann solution. The comparison of numerical results with the analytical solution indicated that the modified SPH method has more advantages than the traditional SPH method. Using the modified SPH algorithm, a series of one-dimensional planar wave propagation problems were investigated, focusing on the influence of the air-gap between the high-pressure air and water and the thickness of water. The numerical results showed that water mitigation effect is significant. Up to 60% shock wave pressure reduction could be achieved with the existence of water, and the shape of shock wave was also changed greatly. It is seemly that the small air-gap between the high-pressure air and water has more influence on water mitigation effect.
文摘We first establish a integral inequality for compact maximal space-like subman ifolds in pseudo-Riemannian manifolds Np(n+p). Then, we investigate compact space-like sub manifolds and hupersurfaces with parallel second fundamental form in Np(n+p) and some other ambient spaces. We obtain some distribution theorems for the square norm of the second fundamental form.
文摘The conjugate of T-connection in a Riemannian manifold is obtained, also some of its properties are studied. T-statistical manifold is defined and was considered. Finally a characteristic vector field of the deformation algebra （M, , ） is also obtained.
文摘This paper considers the existence problem of an elliptic equation, which is equivalent to the prescribing conformal Gaussian curvature problem on R^2. An existence result is proved. In particular, K（x） is allowed to be unbounded above.
基金Supported by the China National Education Committee Science Foundation
文摘This paper considers the existence problem of an elliptic equation, which is equivalent to solving the so called prescribing conformal Gaussian curvature problem on the hyperbolic disc H^2. An existence result is proved. In particular, K（x） is allowed to be unbounded above.
文摘in this paper,we prove that a complete n-dimensional Riemannian manifold with nonnegative kth-Ricci curvature, large volume growth has finite topological type provided that lim r→∞{（vol[B（p.r]/ωnrn-αM）rk（n-1）/k＋1（1-α/2）}≤for some COllstant ε〉0 We also prove that a conlplete Riemannian manifold with nonnegative kth-Ricci curvature and undler some pinching conditions is diffeomorphic to R^n.
文摘In this paper, we present Euler-Lagrange and Hamilton mechanical equations introduced on Riemann almost contact space of a Cartan space of order two. In the conclusion we discussed differential geometric and physical results about related mechanical equations.
文摘在以色列犹太人大屠杀纪念馆＂国际义人园＂里,＂国际正义人士——何凤山先生纪念碑＂静静地沐浴着耶路撒冷的阳光,肃穆的石碑上醒目地镌刻着＂永远不能忘记的中国人＂。何凤山（1901年9月10日-1997年9月28日）,中国湖南人,中华民国外交官,因在二战中拯救过数以千计的犹太人,而被誉为＂中国的辛德勒＂,2001年被以色列政府授予＂国际义人＂（RighteousAmong the Nations）称号。去世后才为世人所知1997年深秋,
