排序方式: 共有837条查询结果,搜索用时 18 毫秒
1.
A new type of non-Noether exact invariants and adiabatic invariants of generalized Hamiltonian systems 总被引:1,自引:0,他引:1
For a generalized Hamiltonian system with the action of small forces of perturbation, the Lie symmetries, symmetrical perturbation,
and adiabatic invariants is presented. Based on the invariance of equations of motion for the system under general infinitesimal
transformation of Lie groups, the Lie symmetrical determining equations, and exact invariants of the system are given. Then
the determining equations of Lie symmetrical perturbation and adiabatic invariants of the disturbed systems are obtained.
Furthermore, in the special infinitesimal transformations, two deductions are given. At the end of the paper, one example
is given to illustrate the application of the method and result. 相似文献
2.
3.
4.
By adding one variable to the equality-or inequality-constrained minimization problems, a new simple penalty function is proposed. It is proved to be exact in the sense that under mild assumptions, the local minimizers of this penalty function are precisely the local minimizers of the original problem, when the penalty parameter is sufficiently large. 相似文献
5.
By solving the time-dependent Schro¨dinger equation, the dependence of photoelectron energy spectra on the binding energy of targets, wavelength and the intensity of laser pulse is exhibited and a scaling law of kinetic energy spectra of both the direct and the rescattered photoelectrons is concluded. The scaling law provides a convenient tool to determine the equivalent photoionization process of various atoms or molecules in various laser fields. The verification of the scaling law by independent methods provides incontestable support to the validity of the scaling law. 相似文献
6.
By solving time-dependent Schrödinger equation, the dependence of photoelectron energy spectra on the binding energy of targets, wavelength and intensity of laser pulse is exhibited and a scaling law of kinetic energy spectra of both the direct and the rescattered photoelectrons is concluded. The scaling law provides a convenient tool to determine the equivalent photoionization process of various atoms or molecules in various laser fields. The verification of the scaling law by independent methods provides an incontestable support to the validity of the scaling law. 相似文献
7.
Xiao-Feng Wu 《Tetrahedron letters》2012,53(33):4328-4331
A general zinc-catalyzed oxidation of sulfides to sulfoxides has been developed. All the reactions proceeded at room temperature. Hydrogen peroxide was used as a green oxidant. Twenty-one examples of sulfoxides were prepared in moderate to excellent yields. 相似文献
8.
In this paper, we study the weak type heterodimensional cycle with orbit-flip in its non-transversal orbit by using the local moving frame approach. For the first two subcases, we present the sufficient conditions for the existence, uniqueness and non-coexistence of the homoclinic orbit, heteroclinic orbit and periodic orbit. Based on the bifurcation analysis, the bifurcation surfaces and the existence regions are located. And for the third subcase, we theoretically established both the coexistence conditio... 相似文献
9.
This paper investigates the relationship between topology and generalized rough sets induced by binary relations. Some known results regarding the relation based rough sets are reviewed, and some new results are given. Particularly, the relationship between different topologies corresponding to the same rough set model is examined. These generalized rough sets are induced by inverse serial relations, reflexive relations and pre-order relations, respectively. We point that inverse serial relations are weakest relations which can induce topological spaces, and that different relation based generalized rough set models will induce different topological spaces. We proved that two known topologies corresponding to reflexive relation based rough set model given recently are different, and gave a condition under which the both are the same topology. 相似文献
10.
单调性条件在Fourier级数收敛性中的最终推广:历史、发展、应用和猜想 总被引:1,自引:0,他引:1
为了对Fourier级数进行近似计算和有效应用,必须研究其收敛性,这个课题有长久的历史,形成了数学分析中吸引包括许多著名数学家在内的学者研究的一条热烈但困难的主流.其中,在三角级数(Fourier级数)一致收敛性和平均收敛性问题中人们一直关心Fourier系数的单调递减条件最终的推广.这个开始于英国Chaundy-Jollife(1916年)和Young(1913年)的工作最近出现了突破性的进展,产生了许多完善的结果.本文将对这方面的历史、发展给出综述,并重点介绍最近的应用成果,并对以后的工作给出研究思路和线索. 相似文献