The multisymplectic geometry for the seismic wave equation is presented in this paper.The local energy conservation law,the local momentum evolution equations,and the multisymplectic form are derived directly from the...The multisymplectic geometry for the seismic wave equation is presented in this paper.The local energy conservation law,the local momentum evolution equations,and the multisymplectic form are derived directly from the variational principle.Based on the covariant Legendre transform,the multisymplectic Hamiltonian formulation is developed.Multisymplectic discretization and numerical experiments are also explored.展开更多
In thermoacoustic system,the characteristic of complex compliance of a regenerator has a great influence on energy stored and dissipation of the whole engine.In order to investigate the performance of regenerators wit...In thermoacoustic system,the characteristic of complex compliance of a regenerator has a great influence on energy stored and dissipation of the whole engine.In order to investigate the performance of regenerators with different matrix geometries and materials coupled with different acoustic systems,an experimental measurement and analysis method was presented.By measuring the resonant frequency,the complex compliance and quality factor of five kinds of matrix were experimentally analyzed respectively in the system of loudspeaker-driven thermoacoustic resonator(TAR)with different lengths.The experimental results show that the real part of complex compliance of the regenerator with pin-array has a maximum value among the measured matrixes and its quality factor is the largest(28.222)with the least dissipation factor of 0.035 4.So the pin-array matrix is testified to behave more excellently on the energy conversion than other matrixes.Compared with other factors the complex compliance of a regenerator contributes more to the performance of a thermoacoustic system.展开更多
In this paper, we first prove a vanishing theorem of relative Gromov-Witten invariant of Pl-bundle. Based on this vanishing theorem and degeneration formula, we obtain a comparison theorem between absolute and relativ...In this paper, we first prove a vanishing theorem of relative Gromov-Witten invariant of Pl-bundle. Based on this vanishing theorem and degeneration formula, we obtain a comparison theorem between absolute and relative Gromov-Witten invariant under some positive condition of the symplectic divisor.展开更多
A mass-conservative average flow model based on the finite element method(FEM) is introduced to predict the performances of textured surfaces applied in mechanical seals or thrust bearings.In this model,the Jakobsson-...A mass-conservative average flow model based on the finite element method(FEM) is introduced to predict the performances of textured surfaces applied in mechanical seals or thrust bearings.In this model,the Jakobsson-Floberg-Olsson(JFO) boundary conditions are applied to the average flow model for ensuring the mass-conservative law.Moreover,the non-uniform triangular grid is utilized,which can deal with the problem of complex geometric shapes.By adopting the modeling techniques,the model proposed here is capable of dealing with complex textured surfaces.The algorithm is proved correct by the numerical experiment.In addition,the model is employed to gain further insight into the influences of the dimples with different shapes and orientations on smooth and rough surfaces on the load-carrying capacity.展开更多
The original Erdos-Ko-Rado problem has inspired much research. It started as a study on sets of pairwise intersecting k-subsets in an n-set, then it gave rise to research on sets of pairwise non-trivially intersecting...The original Erdos-Ko-Rado problem has inspired much research. It started as a study on sets of pairwise intersecting k-subsets in an n-set, then it gave rise to research on sets of pairwise non-trivially intersecting k-dimensional vector spaces in the vector space V（n, q） of dimension n over the finite field of order q, and then research on sets of pairwise non-trivially intersecting generators and planes in finite classical polar spaces. We summarize the main results on the Erdos-Ko-Rado problem in these three settings, mention the ErdSs-Ko-Rado problem in other related settings, and mention open problems for future research.展开更多
文摘The multisymplectic geometry for the seismic wave equation is presented in this paper.The local energy conservation law,the local momentum evolution equations,and the multisymplectic form are derived directly from the variational principle.Based on the covariant Legendre transform,the multisymplectic Hamiltonian formulation is developed.Multisymplectic discretization and numerical experiments are also explored.
基金Projects(50676068,50576024)supported by the National Natural Science Foundation of China
文摘In thermoacoustic system,the characteristic of complex compliance of a regenerator has a great influence on energy stored and dissipation of the whole engine.In order to investigate the performance of regenerators with different matrix geometries and materials coupled with different acoustic systems,an experimental measurement and analysis method was presented.By measuring the resonant frequency,the complex compliance and quality factor of five kinds of matrix were experimentally analyzed respectively in the system of loudspeaker-driven thermoacoustic resonator(TAR)with different lengths.The experimental results show that the real part of complex compliance of the regenerator with pin-array has a maximum value among the measured matrixes and its quality factor is the largest(28.222)with the least dissipation factor of 0.035 4.So the pin-array matrix is testified to behave more excellently on the energy conversion than other matrixes.Compared with other factors the complex compliance of a regenerator contributes more to the performance of a thermoacoustic system.
基金supported by National Natural Science Foundation of China (Grant Nos.10825105 and 11228101)National Science Foundation of the USA
文摘In this paper, we first prove a vanishing theorem of relative Gromov-Witten invariant of Pl-bundle. Based on this vanishing theorem and degeneration formula, we obtain a comparison theorem between absolute and relative Gromov-Witten invariant under some positive condition of the symplectic divisor.
基金supported by the National Basic Research Program of China(Grant No.2009CB724304)the National Key Technology R&D Program(Grant No.2011BAF09B05)+1 种基金the National Natural Science Foundation of China(Grant No.50975157)the Key Research Program of the State Key Laboratory of Tribology of Tsinghua University(Grant No.SKLT08A06)
文摘A mass-conservative average flow model based on the finite element method(FEM) is introduced to predict the performances of textured surfaces applied in mechanical seals or thrust bearings.In this model,the Jakobsson-Floberg-Olsson(JFO) boundary conditions are applied to the average flow model for ensuring the mass-conservative law.Moreover,the non-uniform triangular grid is utilized,which can deal with the problem of complex geometric shapes.By adopting the modeling techniques,the model proposed here is capable of dealing with complex textured surfaces.The algorithm is proved correct by the numerical experiment.In addition,the model is employed to gain further insight into the influences of the dimples with different shapes and orientations on smooth and rough surfaces on the load-carrying capacity.
基金supported by FWO-Vlaanderen(Research Foundation-Flanders)
文摘The original Erdos-Ko-Rado problem has inspired much research. It started as a study on sets of pairwise intersecting k-subsets in an n-set, then it gave rise to research on sets of pairwise non-trivially intersecting k-dimensional vector spaces in the vector space V（n, q） of dimension n over the finite field of order q, and then research on sets of pairwise non-trivially intersecting generators and planes in finite classical polar spaces. We summarize the main results on the Erdos-Ko-Rado problem in these three settings, mention the ErdSs-Ko-Rado problem in other related settings, and mention open problems for future research.
