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When a solution of the one-dimensional nonlinear Schrodinger equation is disturbed by a harmonic function of the space variable, the solution pattern may drift in space as time evolves. The value and the direction of the drifting velocity vary with time. To understand this phenomenon, a perturbation analysis is performed. The drifting velocity given by the analysis agrees well with the direct numerical result.

We consider the Henon maps h(a,b)(x,y) = (1 - ax(2) + y, bx). For \textbackslash{}b\textbackslash{} is small and b < 0, there is a positive measure set of a values near 2, the corresponding map exhibits a strange attractor Lambda(a,b). In this paper, we construct a trapping region which contains Lambda(a,b) we give an exact description of the basin of these Henon strange attractors Lambda(a,b) and we also describe the non-wandering set of h(a,b) as the union of Lambda(a,b) with a fixed point. (C) 2000 Elsevier Science Ltd. All rights reserved.

We define the Lagrangians in the momentum space and in mixed position-momentum spaces. In terms of the so-defined Lagrangians, the actions and the propagators are directly defined in the spaces, not as the Fourier transforms of their counterparts in the configuration space as previously known in the literature. (C) 2000 Elsevier Science B.V. All lights reserved.

We consider the Henon maps h(a,b)(x,y) = (1 - ax(2) + y, bx). For \textbackslash{}b\textbackslash{} is small and b < 0, there is a positive measure set of a values near 2, the corresponding map exhibits a strange attractor Lambda(a,b). In this paper, we construct a trapping region which contains Lambda(a,b) we give an exact description of the basin of these Henon strange attractors Lambda(a,b) and we also describe the non-wandering set of h(a,b) as the union of Lambda(a,b) with a fixed point. (C) 2000 Elsevier Science Ltd. All rights reserved.

When a solution of the one-dimensional nonlinear Schrodinger equation is disturbed by a harmonic function of the space variable, the solution pattern may drift in space as time evolves. The value and the direction of the drifting velocity vary with time. To understand this phenomenon, a perturbation analysis is performed. The drifting velocity given by the analysis agrees well with the direct numerical result.

We define the Lagrangians in the momentum space and in mixed position-momentum spaces. In terms of the so-defined Lagrangians, the actions and the propagators are directly defined in the spaces, not as the Fourier transforms of their counterparts in the configuration space as previously known in the literature. (C) 2000 Elsevier Science B.V. All lights reserved.

We consider the Henon maps h(a,b)(x,y) = (1 - ax(2) + y, bx). For \textbackslash{}b\textbackslash{} is small and b < 0, there is a positive measure set of a values near 2, the corresponding map exhibits a strange attractor Lambda(a,b). In this paper, we construct a trapping region which contains Lambda(a,b) we give an exact description of the basin of these Henon strange attractors Lambda(a,b) and we also describe the non-wandering set of h(a,b) as the union of Lambda(a,b) with a fixed point. (C) 2000 Elsevier Science Ltd. All rights reserved.

When a solution of the one-dimensional nonlinear Schrodinger equation is disturbed by a harmonic function of the space variable, the solution pattern may drift in space as time evolves. The value and the direction of the drifting velocity vary with time. To understand this phenomenon, a perturbation analysis is performed. The drifting velocity given by the analysis agrees well with the direct numerical result.

We define the Lagrangians in the momentum space and in mixed position-momentum spaces. In terms of the so-defined Lagrangians, the actions and the propagators are directly defined in the spaces, not as the Fourier transforms of their counterparts in the configuration space as previously known in the literature. (C) 2000 Elsevier Science B.V. All lights reserved.

We express the detachment cross section caused by a Gaussian pulsed laser in terms of that caused by a continuous laser. Using this expression and Poisson's summation formula, we derive a uniform semiclassical formula for the cross section of pulsed-laser photodetachment of a hydrogen ion H- in Static parallel electric and magnetic fields. The uniform semiclassical formula does not have a divergence problem at the bifurcation points. Numerical comparisons show an excellent agreement between the uniform semiclassical formula and the quantum formula for the detachment cross section.

We express the detachment cross section caused by a Gaussian pulsed laser in terms of that caused by a continuous laser. Using this expression and Poisson's summation formula, we derive a uniform semiclassical formula for the cross section of pulsed-laser photodetachment of a hydrogen ion H- in Static parallel electric and magnetic fields. The uniform semiclassical formula does not have a divergence problem at the bifurcation points. Numerical comparisons show an excellent agreement between the uniform semiclassical formula and the quantum formula for the detachment cross section.

Electroluminescent devices have been fabricated by depositing Al-doped ZnSTe onto GaAs substrates by molecular beam epitaxy. A moderately bright blue-light emission was observed at room temperature. Electroluminescence spectra reveal that light emission is mostly from impact excitation of Te Isoelectronic centers in these structures. Surface morphologies and concurrent current images by using conducting atomic force microscopy indicate electrical inhomogeneity in such structures. Nonuniform light emission may be inferred from nonuniform current distributions on the submicrometer scale. (C) 1998 American Vacuum Society.

Electroluminescent devices have been fabricated by depositing Al-doped ZnSTe onto GaAs substrates by molecular beam epitaxy. A moderately bright blue-light emission was observed at room temperature. Electroluminescence spectra reveal that light emission is mostly from impact excitation of Te Isoelectronic centers in these structures. Surface morphologies and concurrent current images by using conducting atomic force microscopy indicate electrical inhomogeneity in such structures. Nonuniform light emission may be inferred from nonuniform current distributions on the submicrometer scale. (C) 1998 American Vacuum Society.

Electroluminescent devices have been fabricated by depositing Al-doped ZnSTe onto GaAs substrates by molecular beam epitaxy. A moderately bright blue-light emission was observed at room temperature. Electroluminescence spectra reveal that light emission is mostly from impact excitation of Te Isoelectronic centers in these structures. Surface morphologies and concurrent current images by using conducting atomic force microscopy indicate electrical inhomogeneity in such structures. Nonuniform light emission may be inferred from nonuniform current distributions on the submicrometer scale. (C) 1998 American Vacuum Society.

In this article we discuss the symmetries of periodic solutions to Hamiltonian systems with two degrees of freedom in mechanical form. The possible symmetries of such periodic trajectories are generated by spatial symmetries (a finite subgroup of O(2)), phase-shift symmetries (the circle group S-1), and a time-reversing symmetry (associated with mechanical form). We focus on the symmetries and structures of the trajectories in configuration space (R(2)), showing that special properties such as self-intersections and brake orbits are consequences of symmetry.

In this article we discuss the symmetries of periodic solutions to Hamiltonian systems with two degrees of freedom in mechanical form. The possible symmetries of such periodic trajectories are generated by spatial symmetries (a finite subgroup of O(2)), phase-shift symmetries (the circle group S-1), and a time-reversing symmetry (associated with mechanical form). We focus on the symmetries and structures of the trajectories in configuration space (R(2)), showing that special properties such as self-intersections and brake orbits are consequences of symmetry.

In this article we discuss the symmetries of periodic solutions to Hamiltonian systems with two degrees of freedom in mechanical form. The possible symmetries of such periodic trajectories are generated by spatial symmetries (a finite subgroup of O(2)), phase-shift symmetries (the circle group S-1), and a time-reversing symmetry (associated with mechanical form). We focus on the symmetries and structures of the trajectories in configuration space (R(2)), showing that special properties such as self-intersections and brake orbits are consequences of symmetry.