The general principle of utilizing the BGK equation to simulate a macroscopic gas flow is illustrated. Two typical examples, i.e., a low-speed axisymmetric submerged jet and the Prandtl-Meyer expansion to a vacuum, ar...The general principle of utilizing the BGK equation to simulate a macroscopic gas flow is illustrated. Two typical examples, i.e., a low-speed axisymmetric submerged jet and the Prandtl-Meyer expansion to a vacuum, are presented for validating the feasibility and accuracy of the BGK-equation simulation in continuum and non-continuum flow regimes. This approach is then used to simulate the exhaust plume formed by a small manoeuvre thruster of an artificial satellite in the outer space. The plume impingement on a flat surface perpendicular to the nozzle axis is also simulated by the same method. In the latter case the impingement force acting on the flat surface is calculated. When the flow reaches to the steady state the calculated impingement force is reasonably compared with the theoretical value of the nozzle thrust.展开更多
The purpose of this article is to prescnt by using vector space methods. a formula as how to calculate the covariance of the outer product of two independent random vecters in inter product space and to makes a discus...The purpose of this article is to prescnt by using vector space methods. a formula as how to calculate the covariance of the outer product of two independent random vecters in inter product space and to makes a discussion on the covariance of the orthogonally invariant random vector and that of the weakly spherically distributed orter produt.展开更多
Let （Φ,Ψ） be a pair of complementary N-functions and HΦ（A） and HΨ（A） be the associated noncommutative Orlicz-Hardy spaces. We extend the Riesz, Szeg＆#168;o and inner-outer type factorization theorems of Hp...Let （Φ,Ψ） be a pair of complementary N-functions and HΦ（A） and HΨ（A） be the associated noncommutative Orlicz-Hardy spaces. We extend the Riesz, Szeg＆#168;o and inner-outer type factorization theorems of Hp（A） to this case.展开更多
We identify the functions whose polynomial multiples are weak＊ dense in Qp spaces and prove that if ｜f（z）｜ ≥ ｜g（z）｜ and g is cyclic in Qp, then f is cyclic in Qp. We also show that the multiplication operato...We identify the functions whose polynomial multiples are weak＊ dense in Qp spaces and prove that if ｜f（z）｜ ≥ ｜g（z）｜ and g is cyclic in Qp, then f is cyclic in Qp. We also show that the multiplication operator Mx on Qp spaces is cellular indecomposable.展开更多
In the early 1960s,with the ad-vent of the space era,it was quick-ly recognized that any object inspace was at risk due to the naturalmeteoroid environment.In the late1960s,it was recognized that
In this note,we give some conditions concerning that the countably bi-quotient closed mappings, and the closed mappings with each fiber having a σ-closure preserving outer base, preserve M1-spaces.
基金The project supported by Beijing Institute of Spacecraft Overall Design
文摘The general principle of utilizing the BGK equation to simulate a macroscopic gas flow is illustrated. Two typical examples, i.e., a low-speed axisymmetric submerged jet and the Prandtl-Meyer expansion to a vacuum, are presented for validating the feasibility and accuracy of the BGK-equation simulation in continuum and non-continuum flow regimes. This approach is then used to simulate the exhaust plume formed by a small manoeuvre thruster of an artificial satellite in the outer space. The plume impingement on a flat surface perpendicular to the nozzle axis is also simulated by the same method. In the latter case the impingement force acting on the flat surface is calculated. When the flow reaches to the steady state the calculated impingement force is reasonably compared with the theoretical value of the nozzle thrust.
文摘The purpose of this article is to prescnt by using vector space methods. a formula as how to calculate the covariance of the outer product of two independent random vecters in inter product space and to makes a discussion on the covariance of the orthogonally invariant random vector and that of the weakly spherically distributed orter produt.
文摘Let （Φ,Ψ） be a pair of complementary N-functions and HΦ（A） and HΨ（A） be the associated noncommutative Orlicz-Hardy spaces. We extend the Riesz, Szeg＆#168;o and inner-outer type factorization theorems of Hp（A） to this case.
基金supported by NNSF of China (10771130)Specialized Research Fund for the Doctoral Program of High Education (2007056004)+1 种基金NSF of GuangdongProvince (10151503101000025)NSF of Fujian Province (2009J01004)
文摘We identify the functions whose polynomial multiples are weak＊ dense in Qp spaces and prove that if ｜f（z）｜ ≥ ｜g（z）｜ and g is cyclic in Qp, then f is cyclic in Qp. We also show that the multiplication operator Mx on Qp spaces is cellular indecomposable.
文摘In the early 1960s,with the ad-vent of the space era,it was quick-ly recognized that any object inspace was at risk due to the naturalmeteoroid environment.In the late1960s,it was recognized that
文摘In this note,we give some conditions concerning that the countably bi-quotient closed mappings, and the closed mappings with each fiber having a σ-closure preserving outer base, preserve M1-spaces.
