共查询到18条相似文献,搜索用时 156 毫秒
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研究广义经典力学系统的对称性与守恒定理.利用常微分方程在无限小变换下的不变性,建 立了系统在高维增广相空间中仅依赖于正则变量的Lie对称变换,并直接由系统的Lie对称性得到了系统的一类守恒律.实际上,这是Hojman的守恒定理对广义经典力学系统的推广.举例说明结果的应用.
关键词:
广义经典力学
对称性
守恒定理 相似文献
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引入了广义动能概念,利用勒让德变换导出了方程中的偏导数是关于广义动能偏导数的理想完整约束系统哈密顿正则方程,据此讨论了有关守恒律. 相似文献
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利用代数方程和微分方程在无限小变换下的不变性,研究带有伺服约束的非完整系统的Lie 对称性.给出Lie对称性的确定方程、限制方程、结构方程,并给出守恒量的形式.
关键词:
非完整系统
伺服约束
Lie对称性
守恒量 相似文献
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A New Conservation Law Derived from Mei Symmetry for the System
of Generalized Classical Mechanics 总被引:1,自引:0,他引:1
A new conservation theorem derived directly from Mei symmetry of the generalized classical mechanical system is presented. First, the differential equations of motion of the system are established, and the definition and criterion of Mei symmetry for the system of generalized classical mechanics are given, which are based upon the invariance of dynamical functions under irdinitesimal transformations. Second, the condition under which a Mei symmetry can lead to a new conservation law is obtained and the form of the conservation law is presented. And finadly, an example is given to illustrate the application of the results. 相似文献
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A new conservation theorem derived directly from Mei symmetry of the generalized classical mechanical system is presented. First, the differential equations of motion of the system are established, and the definition and criterion of Mei symmetry for the system of generalized classical mechanics are given, which are based upon the invariance of dynamical functions under infinitesimal transformations. Second, the condition under which a Mei symmetry can lead to a new conservation law is obtained and the form of the conservation law is presented. And finally, an example is given to illustrate the application of the results. 相似文献
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A new type of adiabatic invariants for nonconservative systems of generalized classical mechanics 总被引:1,自引:0,他引:1
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The perturbations to symmetries and adiabatic invariants for nonconservative systems
of generalized classical mechanics are studied. The exact invariant in the form of
Hojman from a particular Lie symmetry for an undisturbed system of generalized
mechanics is given. Based on the concept of high-order adiabatic invariant in
generalized mechanics, the perturbation to Lie symmetry for the system under the
action of small disturbance is investigated, and a new adiabatic invariant for the
nonconservative system of generalized classical mechanics is obtained, which can be
called the Hojman adiabatic invariant. An example is also given to illustrate the
application of the results. 相似文献
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We consider the problem of defining completely a class of additive conservation laws for the generalized Liouville equation whose characteristics are given by an arbitrary system of first-order ordinary differential equations. We first show that if the conservation law, a time-invariant functional, is additive on functions having disjoint compact support in phase space, then it is represented by an integral over phase space of a kernel which is a function of the solution to the Liouville equation. Then we use the fact that in classical mechanics phase space is usually a direct product of physical space and velocity space (Newtonian systems). We prove that for such systems the aforementioned representation of the invariant functionals will hold for conservation laws which are additive only in physical space; i.e., additivity in physical space automatically implies additivity in the whole phase space. We extend the results to include non-degenerate Hamiltonian systems, and, more generally, to include both conservative and dissipative dynamical systems. Some applications of the results are discussed. 相似文献
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SYMMETRIES AND CONSERVED QUANTITIES FOR SYSTEMS OF GENERALIZED CLASSICAL MECHANICS 总被引:4,自引:0,他引:4
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In this paper, the symmetries and the conserved quantities for systems of generalized classical mechanics are studied. First, the generalized Noether's theorem and the generalized Noether's inverse theorem of the systems are given, which are based upon the invariant properties of the canonical action with respect to the action of the infinitesimal transformation of r-parameter finite group of transformation; second, the Lie symmetries and conserved quantities of the systems are studied in accordance with the Lie's theory of the invariance of differential equations under the transformation of infinitesimal groups; and finally, the inner connection between the two kinds of symmetries of systems is discussed. 相似文献