摘要：
Guiding center equations of particle motion under a toroidal magnetic configuration were derived using a new defined magnetic flux coordinates system. A transformation method to Hamiltonian canonical variables is presented in this work. It was found that the newly defined flux coordinates are simple self-consistent, and could be applied to any magnetostatic equilibrium with a nested flux configuration.
摘要：
In this paper, we investigate the existence of multiple positive periodic solutions to a class of functional difference equations. We answer the open problems proposed by Y. Raffoul in [Electron. J. Differential Equations 55 (2002) 1-8] and the conditions obtained improve some recent results established there. (c) 2004 Elsevier Inc. All rights reserved.
