日本のコーポレート・ガヴァナンス改革 : その企業動態への効果と労働への余波

筑波大学 (University of Tsukuba)201

日本のコーポレート・ガヴァナンス改革 : その企業動態への効果と労働への余波

筑波大学 (University of Tsukuba)201

A heat transfer with a source: the complete set of invariant difference schemes

In this letter we present the set of invariant difference equations and meshes which preserve the Lie group symmetries of the equation u_{t}=(K(u)u_{x})_{x}+Q(u). All special cases of K(u) and Q(u) that extend the symmetry group admitted by the differential equation are considered. This paper completes the paper [J. Phys. A: Math. Gen. 30, no. 23 (1997) 8139-8155], where a few invariant models for heat transfer equations were presented.Comment: arxiv version is already officia

The higher order C_n dispersion coefficients for the alkali atoms

The van der Waals coefficients, from C_11 through to C_16 resulting from 2nd, 3rd and 4th order perturbation theory are estimated for the alkali (Li, Na, K and Rb) atoms. The dispersion coefficients are also computed for all possible combinations of the alkali atoms and hydrogen. The parameters are determined from sum-rules after diagonalizing the fixed core Hamiltonian in a large basis. Comparisons of the radial dependence of the C_n/r^n potentials give guidance as to the radial regions in which the various higher-order terms can be neglected. It is seen that including terms up to C_10/r^10 results in a dispersion interaction that is accurate to better than 1 percent whenever the inter-nuclear spacing is larger than 20 a_0. This level of accuracy is mainly achieved due to the fortuitous cancellation between the repulsive (C_11, C_13, C_15) and attractive (C_12, C_14, C_16) dispersion forces.Comment: 8 pages, 7 figure

Symmetry-preserving discrete schemes for some heat transfer equations

Lie group analysis of differential equations is a generally recognized method, which provides invariant solutions, integrability, conservation laws etc. In this paper we present three characteristic examples of the construction of invariant difference equations and meshes, where the original continuous symmetries are preserved in discrete models. Conservation of symmetries in difference modeling helps to retain qualitative properties of the differential equations in their difference counterparts.Comment: 21 pages, 4 ps figure

Infinite series solutions of the symmetry equation for the 1+21 +2 dimensional continuous Toda chain

A sequence of solutions to the equation of symmetry for the continuous Toda chain in $1+2$ dimensions is represented in explicit form. This fact leads to the supposition that this equation is completely integrable.Comment: 9 pages, latex, no figure

The variational symmetries and conservation laws in classical theory of Heisenberg (anti)ferromagnet

The nonlinear partial differential equations describing the spin dynamics of Heisenberg ferro and antiferromagnet are studied by Lie transformation group method. The generators of the admitted variational Lie symmetry groups are derived and conservation laws for the conserved currents are found via Noether's theorem