The abundance of neutral hydrogen（HI）in satellite galaxies in the local group is important for studying the formation history of our local group.In this work,we generated mock HI satellite galaxies in the Local Grou...The abundance of neutral hydrogen（HI）in satellite galaxies in the local group is important for studying the formation history of our local group.In this work,we generated mock HI satellite galaxies in the Local Group using the high mass-resolution hydrodynamic APOSTLE simulation.The simulated HI mass function agrees with the ALFALFA survey very well above 10~6M_⊙,although there is a discrepancy below this scale because of the observed flux limit.After carefully checking various systematic elements in the observations,including fitting of line width,sky coverage,integration time and frequency drift due to uncertainty in a galaxy’s distance,we predicted the abundance of HI in galaxies in a future survey that will be conducted by FAST.FAST has a larger aperture and higher sensitivity than the Arecibo telescope.We found that the HI mass function could be estimated well around 10~5M_⊙ if the integration time is 40 minutes.Our results indicate that there are 61 HI satellites in the Local Group and 36 in the FAST field above 10~5M_⊙.This estimation is one order of magnitude better than the current data,and will put a strong constraint on the formation history of the Local Group.Also more high resolution simulated samples are needed to achieve this target.展开更多
The lack of Birkhoff theorem in finite-range gravitation reveals nonzero acceleration of the test body inside the massive spherical shell, as well as breakdown of screening inside the charged conductor gives rise to a...The lack of Birkhoff theorem in finite-range gravitation reveals nonzero acceleration of the test body inside the massive spherical shell, as well as breakdown of screening inside the charged conductor gives rise to acceleration of the test charge. An application of this effect to the motion of galaxies in Local Group allows to constraint quintessence parameter in some massive gravitational theories.展开更多
Let R be an associative ring with identity. R is said to be semilocal if R/J（R） is （semisimple） Artinian, where J（R） denotes the Jacobson radical of R. In this paper, we give necessary and sufficient conditions ...Let R be an associative ring with identity. R is said to be semilocal if R/J（R） is （semisimple） Artinian, where J（R） denotes the Jacobson radical of R. In this paper, we give necessary and sufficient conditions for the group ring RG to be semilocal, where G is a locally finite nilpotent group.展开更多
For locally compact groups G, Kuan Yuan studied a notion of inner amenability groups, that is, if there exists an inner invariant mean on G. In this article, among other things, the author investigates the inner amena...For locally compact groups G, Kuan Yuan studied a notion of inner amenability groups, that is, if there exists an inner invariant mean on G. In this article, among other things, the author investigates the inner amenability on a locally compact group G. The author gives sufficient conditions and some necessary conditions about G to have an inner invariant mean.展开更多
The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity ...The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity and topography of the seabed were measured based on a system composed of plane positioning equipment and an ADV.Experimental results indicate that the development of the scour hole was fast at the beginning, but then the scour rate decreased until reaching equilibrium. Erosion would occur around each pile of the foundation. In most cases, the scour pits were connected in pairs and the outside widths of the scour holes were larger than the inner widths. The maximum scour depth occurred at the side pile of the foundation for each test. In addition, a preliminary investigation shows that the larger the flow velocity, the larger the scour hole dimensions but the shorter equilibrium time. The field maximum scour depth around the foundation was obtained based on the physical experiments with the geometric length scales of 1:27.0, 1:42.5 and 1:68.0, and it agrees with the scour depth estimated by the HEC-18 equation.展开更多
By means of the modified Clarkson and Kruskal （CK） direct method and the variable separation approach, we investigate the （24-1）-dimensional Ito equation which was constructed by Ito in 1980. The full symmetry gro...By means of the modified Clarkson and Kruskal （CK） direct method and the variable separation approach, we investigate the （24-1）-dimensional Ito equation which was constructed by Ito in 1980. The full symmetry group with the Kac-Moody-Virasoro algebra structure and the variable separation solutions are obtained. By selecting appropriate arbitrary functions, some special soliton excitations are shown graphically. The results presented here would be beneficial for understanding the （2-t-1）-dimensional Ito equation better.展开更多
In this note, we consider the multipliers on weighted function spaces over totally disconnected locally compact abelian groups (Vilenkin groups). Firstly we show an (H1 ,L ) multiplier result. We also give an (Hap ,Ha...In this note, we consider the multipliers on weighted function spaces over totally disconnected locally compact abelian groups (Vilenkin groups). Firstly we show an (H1 ,L ) multiplier result. We also give an (Hap ,Hap) multiplier result under a similiar condition of Lu Yang type. In section 2, we obtain a result about the boundedness of multipliers on weighted Besov spaces.展开更多
Let G be a Heisenberg group over local field K. In the paper we give some local maximal functions which define the Hardy spaces h(P)(G) equivalently, obtain the atomic decomposition of local Hardy spaces. We also give...Let G be a Heisenberg group over local field K. In the paper we give some local maximal functions which define the Hardy spaces h(P)(G) equivalently, obtain the atomic decomposition of local Hardy spaces. We also give some bounded convolution operators h(P)(G), from which we can characterize h(P)(G) by sqare functions.展开更多
All graphs are finite simple undirected and of no isolated vertices in this paper. Using the theory of coset graphs and permutation groups, it is completed that a classification of locally transitive graphs admitting ...All graphs are finite simple undirected and of no isolated vertices in this paper. Using the theory of coset graphs and permutation groups, it is completed that a classification of locally transitive graphs admitting a non-Abelian group with cyclic Sylow subgroups. They are either the union of the family of arc-transitive graphs, or the union of the family of bipartite edge-transitive graphs.展开更多
Let F be a field of characteristic not 2, and let A be a finite-dimensional semisimple F -algebra. All local automorphisms of A are characterized when all the degrees of A are larger than 1. If F is further assumed to...Let F be a field of characteristic not 2, and let A be a finite-dimensional semisimple F -algebra. All local automorphisms of A are characterized when all the degrees of A are larger than 1. If F is further assumed to be an algebraically closed field of characteristic zero, K a finite group, F K the group algebra of K over F , then all local automorphisms of F K are also characterized.展开更多
In this paper, the finite symmetry transformation group of the （2＋1）-dimensional coupled Burgers equation is studied by the modified direct method, and with the help of the truncated Painleve′ expansion approach, ...In this paper, the finite symmetry transformation group of the （2＋1）-dimensional coupled Burgers equation is studied by the modified direct method, and with the help of the truncated Painleve′ expansion approach, some special localized structures for the （2＋1）-dimensional coupled Burgers equation are obtained, in particular, the dromion-like and solitoff-like structures.展开更多
基金support by China Program of International S&T Cooperation(2016YFE0100300)support by the National Natural Science Foundation of China(NSFC,Grant Nos.11633004,11390372,11303008 and 11773034)+1 种基金the 973 program grant 2015CB857005the NSFC(No.11373029)
文摘The abundance of neutral hydrogen（HI）in satellite galaxies in the local group is important for studying the formation history of our local group.In this work,we generated mock HI satellite galaxies in the Local Group using the high mass-resolution hydrodynamic APOSTLE simulation.The simulated HI mass function agrees with the ALFALFA survey very well above 10~6M_⊙,although there is a discrepancy below this scale because of the observed flux limit.After carefully checking various systematic elements in the observations,including fitting of line width,sky coverage,integration time and frequency drift due to uncertainty in a galaxy’s distance,we predicted the abundance of HI in galaxies in a future survey that will be conducted by FAST.FAST has a larger aperture and higher sensitivity than the Arecibo telescope.We found that the HI mass function could be estimated well around 10~5M_⊙ if the integration time is 40 minutes.Our results indicate that there are 61 HI satellites in the Local Group and 36 in the FAST field above 10~5M_⊙.This estimation is one order of magnitude better than the current data,and will put a strong constraint on the formation history of the Local Group.Also more high resolution simulated samples are needed to achieve this target.
文摘The lack of Birkhoff theorem in finite-range gravitation reveals nonzero acceleration of the test body inside the massive spherical shell, as well as breakdown of screening inside the charged conductor gives rise to acceleration of the test charge. An application of this effect to the motion of galaxies in Local Group allows to constraint quintessence parameter in some massive gravitational theories.
基金Foundation item:The NNSF(10571026)of China,the NSF(BK2005207)of Jiangsu Provincethe Specialized Research Fund(20060286006)for the Doctoral Program of Higher Education.
文摘Let R be an associative ring with identity. R is said to be semilocal if R/J（R） is （semisimple） Artinian, where J（R） denotes the Jacobson radical of R. In this paper, we give necessary and sufficient conditions for the group ring RG to be semilocal, where G is a locally finite nilpotent group.
文摘For locally compact groups G, Kuan Yuan studied a notion of inner amenability groups, that is, if there exists an inner invariant mean on G. In this article, among other things, the author investigates the inner amenability on a locally compact group G. The author gives sufficient conditions and some necessary conditions about G to have an inner invariant mean.
基金financially supported by the National Key Research and Development Program of China(Grant No.2017YFC1404200)the Tianjin Key Program of Applied Foundation and Advanced-Tech Research,China(Grant No.18JCZDJC40200)+1 种基金the National High Technology Research and Development Program of China(863 Program,Grant No.2012AA051709)the National Natural Science Foundation of China(Grant No.51509183)
文摘The local scour around a new pile-group foundation of offshore wind turbine subjected to a bi-directional current was physically modeled with a bi-directional flow flume. In a series of experiments, the flow velocity and topography of the seabed were measured based on a system composed of plane positioning equipment and an ADV.Experimental results indicate that the development of the scour hole was fast at the beginning, but then the scour rate decreased until reaching equilibrium. Erosion would occur around each pile of the foundation. In most cases, the scour pits were connected in pairs and the outside widths of the scour holes were larger than the inner widths. The maximum scour depth occurred at the side pile of the foundation for each test. In addition, a preliminary investigation shows that the larger the flow velocity, the larger the scour hole dimensions but the shorter equilibrium time. The field maximum scour depth around the foundation was obtained based on the physical experiments with the geometric length scales of 1:27.0, 1:42.5 and 1:68.0, and it agrees with the scour depth estimated by the HEC-18 equation.
基金Supported by the Zhejiang Provincial Natural Science Foundation of China under Grant No LQ13A010014the National Natural Science Foundation of China under Grant Nos 11326164,11401528,11435005 and 11375090+4 种基金the Global Change Research Program of China(No 2015CB953904)the Research Fund for the Doctoral Program of Higher Education of China(No 20120076110024)the Network Information Physics Calculation of Basic Research Innovation Research Group of China under Grant No 61321064Shanghai Collaborative Innovation Center of Trustworthy Software for Internet of Things(No ZF1213)Shanghai Minhang District Talents of High Level Scientific Research Project
文摘By means of the modified Clarkson and Kruskal （CK） direct method and the variable separation approach, we investigate the （24-1）-dimensional Ito equation which was constructed by Ito in 1980. The full symmetry group with the Kac-Moody-Virasoro algebra structure and the variable separation solutions are obtained. By selecting appropriate arbitrary functions, some special soliton excitations are shown graphically. The results presented here would be beneficial for understanding the （2-t-1）-dimensional Ito equation better.
文摘In this note, we consider the multipliers on weighted function spaces over totally disconnected locally compact abelian groups (Vilenkin groups). Firstly we show an (H1 ,L ) multiplier result. We also give an (Hap ,Hap) multiplier result under a similiar condition of Lu Yang type. In section 2, we obtain a result about the boundedness of multipliers on weighted Besov spaces.
文摘Let G be a Heisenberg group over local field K. In the paper we give some local maximal functions which define the Hardy spaces h(P)(G) equivalently, obtain the atomic decomposition of local Hardy spaces. We also give some bounded convolution operators h(P)(G), from which we can characterize h(P)(G) by sqare functions.
基金The NSF (60776810,10871205) of Chinathe NSF (08JCYBJC13900) of Tianjin
文摘All graphs are finite simple undirected and of no isolated vertices in this paper. Using the theory of coset graphs and permutation groups, it is completed that a classification of locally transitive graphs admitting a non-Abelian group with cyclic Sylow subgroups. They are either the union of the family of arc-transitive graphs, or the union of the family of bipartite edge-transitive graphs.
基金Supported by the Fundamental Research Funds for the Central Universities
文摘Let F be a field of characteristic not 2, and let A be a finite-dimensional semisimple F -algebra. All local automorphisms of A are characterized when all the degrees of A are larger than 1. If F is further assumed to be an algebraically closed field of characteristic zero, K a finite group, F K the group algebra of K over F , then all local automorphisms of F K are also characterized.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11175092)the Scientific Research Fund of Education Department of Zhejiang Province of China (Grant No. Y201017148)K. C. Wong Magna Fund in Ningbo University
文摘In this paper, the finite symmetry transformation group of the （2＋1）-dimensional coupled Burgers equation is studied by the modified direct method, and with the help of the truncated Painleve′ expansion approach, some special localized structures for the （2＋1）-dimensional coupled Burgers equation are obtained, in particular, the dromion-like and solitoff-like structures.
