In the light of the local Lorentz transformations and the general Noether theorem, a new formulate ofthe general covariant energy-momentum conservation law in f(R) gravity is obtained, which does not depend on thecoor...In the light of the local Lorentz transformations and the general Noether theorem, a new formulate ofthe general covariant energy-momentum conservation law in f(R) gravity is obtained, which does not depend on thecoordinative choice.展开更多
The theory of action liberal in cause has a long history. But this concept originally did not exist in our country＇s traditional crinainal law. It has caused widespread controversy and discussion after being introduc...The theory of action liberal in cause has a long history. But this concept originally did not exist in our country＇s traditional crinainal law. It has caused widespread controversy and discussion after being introduced into Chinese academy of criminal law. From researches on various viewpoints about the theory of action liberal in cause in German and Japanese theories of criminal law, this paper discusses problems such as recognition of the form of a crime of action liberal in cause, the basis of straPoarkeit and how to coordinate with criminal law principles like ＂capacity for responsibility coexists with capacity for act＂. In the end, it puts forward the scheme of modification for relevant legislation of action liberal in cause.展开更多
Measuring the top coal movement and abutment pressure about Teaching ThirdMine that belonged to the National Energy Investment and Development.It shows that thetop coal's strong compression occurs 6 m in front of ...Measuring the top coal movement and abutment pressure about Teaching ThirdMine that belonged to the National Energy Investment and Development.It shows that thetop coal's strong compression occurs 6 m in front of the face, the top coal is in front of sideabutment pressure concentration increase area at this time, and the top coal horizontaldisplacement increase rapidly.Also analyzed the top coal mechanical properties, and thetop coal under abutment pressure turned into block state.Finally, analyzed the top coalfailure mechanism and the structure of the mechanical model, and also made a theoreticalanalysis of the top coal's ultimate bearing capacity.展开更多
The behavior of graphene bombarded by fullerene(C60 and C70)and its derivatives through using nonequilibrium molecular dynamics method are studied.The microscopic mechanism of passing through graphene is obviously rel...The behavior of graphene bombarded by fullerene(C60 and C70)and its derivatives through using nonequilibrium molecular dynamics method are studied.The microscopic mechanism of passing through graphene is obviously related to the initial structure of destroying carbon-carbon bonds and the strong interaction between the circular region of graphene and the cluster.The probability of passing through graphene depends on the incident velocity of clusters,the species of clusters,the temperature of heat baths,and the defect of graphene.Our results can provide a perspective for further understanding the mechanism of generating nanopores in graphene.The clusters used here may also bring about some potential utilities in tie functionalization of graphene and the production of nanopores.展开更多
Based on a general variational principle, Einstein–Hilbert action and sound facts from geometry, it is shown that the long existing pseudotensor, non-localizability problem of gravitational energy-momentum is a resul...Based on a general variational principle, Einstein–Hilbert action and sound facts from geometry, it is shown that the long existing pseudotensor, non-localizability problem of gravitational energy-momentum is a result of mistaking different geometrical, physical ob jects as one and the same. It is also pointed out that in a curved spacetime, the sum vector of matter energy-momentum over a finite hyper-surface can not be defined. In curvilinear coordinate systems conservation of matter energy-momentum is not the continuity equations for its components. Conservation of matter energy-momentum is the vanishing of the covariant divergence of its density-flux tensor field. Introducing gravitational energy-momentum to save the law of conservation of energy-momentum is unnecessary and improper. After reasonably defining "change of a particle's energy-momentum", we show that gravitational field does not exchange energy-momentum with particles. And it does not exchange energy-momentum with matter fields either. Therefore, the gravitational field does not carry energy-momentum, it is not a force field and gravity is not a natural force.展开更多
A consistent focus in theoretical mechanics has been on how to apply Lagrange's equation to continuum mechanics.This paper uses the concept of a variational derivative and its laws of operation to investigate the ...A consistent focus in theoretical mechanics has been on how to apply Lagrange's equation to continuum mechanics.This paper uses the concept of a variational derivative and its laws of operation to investigate the derivation of Lagrange's equation,which is then applied to nonlinear elasto-dynamics.In accordance with the work-energy principle and the energy conservation law,kinetic and potential energies are proposed for rigid-elastic coupling dynamics,whose governing equation is established by manipulating Lagrange's equation.In addition,case studies are used to demonstrate the application of the proposed method to spacecraft dynamics.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.10905027
文摘In the light of the local Lorentz transformations and the general Noether theorem, a new formulate ofthe general covariant energy-momentum conservation law in f(R) gravity is obtained, which does not depend on thecoordinative choice.
文摘The theory of action liberal in cause has a long history. But this concept originally did not exist in our country＇s traditional crinainal law. It has caused widespread controversy and discussion after being introduced into Chinese academy of criminal law. From researches on various viewpoints about the theory of action liberal in cause in German and Japanese theories of criminal law, this paper discusses problems such as recognition of the form of a crime of action liberal in cause, the basis of straPoarkeit and how to coordinate with criminal law principles like ＂capacity for responsibility coexists with capacity for act＂. In the end, it puts forward the scheme of modification for relevant legislation of action liberal in cause.
文摘Measuring the top coal movement and abutment pressure about Teaching ThirdMine that belonged to the National Energy Investment and Development.It shows that thetop coal's strong compression occurs 6 m in front of the face, the top coal is in front of sideabutment pressure concentration increase area at this time, and the top coal horizontaldisplacement increase rapidly.Also analyzed the top coal mechanical properties, and thetop coal under abutment pressure turned into block state.Finally, analyzed the top coalfailure mechanism and the structure of the mechanical model, and also made a theoreticalanalysis of the top coal's ultimate bearing capacity.
基金Supported in part by the National Natural Science Foundation of China under Grant Nos.11004082,and 11291240477the Natural Science Foundation of Guangdong Province under Grant No.2014A030313367the Fundamental Research Funds for the Central Universities,Jinan University under Grant Nos.21611437 and 11614341
文摘The behavior of graphene bombarded by fullerene(C60 and C70)and its derivatives through using nonequilibrium molecular dynamics method are studied.The microscopic mechanism of passing through graphene is obviously related to the initial structure of destroying carbon-carbon bonds and the strong interaction between the circular region of graphene and the cluster.The probability of passing through graphene depends on the incident velocity of clusters,the species of clusters,the temperature of heat baths,and the defect of graphene.Our results can provide a perspective for further understanding the mechanism of generating nanopores in graphene.The clusters used here may also bring about some potential utilities in tie functionalization of graphene and the production of nanopores.
文摘Based on a general variational principle, Einstein–Hilbert action and sound facts from geometry, it is shown that the long existing pseudotensor, non-localizability problem of gravitational energy-momentum is a result of mistaking different geometrical, physical ob jects as one and the same. It is also pointed out that in a curved spacetime, the sum vector of matter energy-momentum over a finite hyper-surface can not be defined. In curvilinear coordinate systems conservation of matter energy-momentum is not the continuity equations for its components. Conservation of matter energy-momentum is the vanishing of the covariant divergence of its density-flux tensor field. Introducing gravitational energy-momentum to save the law of conservation of energy-momentum is unnecessary and improper. After reasonably defining "change of a particle's energy-momentum", we show that gravitational field does not exchange energy-momentum with particles. And it does not exchange energy-momentum with matter fields either. Therefore, the gravitational field does not carry energy-momentum, it is not a force field and gravity is not a natural force.
基金supported by the National Natural Science Foundation of China(Grant No.10272034)
文摘A consistent focus in theoretical mechanics has been on how to apply Lagrange's equation to continuum mechanics.This paper uses the concept of a variational derivative and its laws of operation to investigate the derivation of Lagrange's equation,which is then applied to nonlinear elasto-dynamics.In accordance with the work-energy principle and the energy conservation law,kinetic and potential energies are proposed for rigid-elastic coupling dynamics,whose governing equation is established by manipulating Lagrange's equation.In addition,case studies are used to demonstrate the application of the proposed method to spacecraft dynamics.
