Using the notion of an isolating block, some existence criteria of trajectories connecting two critical pints of planar dynaniiral
systems are given.
Project supported by the National Natural Science Foundation of China. 相似文献
Classical statistical particle mechanics in the configuration space can be represented by a nonlinear Schrödinger equation. Even without assuming the existence of deterministic particle trajectories, the resulting quantum-like statistical interpretation is sufficient to predict all measurable results of classical mechanics. In the classical case, the wave function that satisfies a linear equation is positive, which is the main source of the fundamental difference between classical and quantum mechanics. 相似文献
The interaction of heavy ions with solids produces a narrow radial core of primary damage. The actual nature of the damage and the mechanism of its formation is not yet fully understood.
The technique of the electrochemical etching of irradiated samples is an useful method to investigate these structures of the track cores. The transversale etching rate as a function of the radius, derived from the time-dependence of the radius of the etching pore, can be interpreted as the corresponding magnitude of the degree of the damage within the track core.
To carry through measurements of smallest radii of etching pores, their very high electric resistance respectively, a sophisticated experimental set-up is required.
An advanced set-up is performed, which enables, by application of a combined d.c.-a.c.-method, to measure the resistance of the sample during the whole etching process, associated with the origin of pore and its growth up to radii of 10 nm and more. 相似文献
Non-overlapping as well as overlapping tracks of energetic ions have been introduced into polyimide foils. After aging their conductivity was measured. This — to our knowledge — first systematic study shows that conductivity does not only result from multiple track overlapping, but can be found already in single ion tracks. This conductivity is shown to be primarily a consequence of electronic energy transfer. The conductivity of single ion tracks is higher than that of typical insulators, but still orders of magnitude lower than that of typical semiconductors. The conductivity is independent of the applied electric field strength until at excessive voltages the electric current increases nonlinearly up to complete breakthrough. The total conductivity of an irradiated polyimide foil increases proportionally with ion fluence for large ion track spacings, and approaches saturation when the electronically active track regimes begin to overlap. Above some thousand times track overlapping however, new chemical and structural changes in the irradiated material lead to another strong increase in conductivity. 相似文献
This paper presents exact solutions in terms of implicit functions and hyperbolic functions to a nonconvex dissipative system,
controlled by a Duffing–van der Pol nonlinear equation with a fifth-order nonlinearity. Applications to the complex Ginzburg–Landau
equation are illustrated and several classes of uniformly translating solutions are obtained accordingly.
Part of the work was announced at the International Conference on Complementarity, Duality, and Global Optimization in Science
and Engineering, Virginia Tech. University, Blacksburg, Virginia, August 15–17, 2005. This work is supported by NSF Grant
CCF–0514768. 相似文献
The problem of determination of momentum distributions of ejected electrons in slow atomic collisions is studied within the
impact-parameter method by using a dynamic adiabatic basis which takes into account the correct boundary conditions. An expression
is obtained which relates the momentum distribution of the ejected electrons with a coherent sum of the delocalized dynamic
adiabatic eigenstates (elementary wavepackets). The form of the momentum distribution exactly coincides with the form of the total wavepacket in configuration space. General formulas are applied to a model problem of
electron detachment in the process in which the electron-atom interactions are described by the zero-range potentials. In the example considered, the momentum
distribution of ejected electrons, in the center-of-mass frame, exhibits a maximum located in the scattering plane on the
circle of radius (in atomic units), where v is the relative collision velocity and is the impact parameter.
Received: 5 October 1998 相似文献