The electric field intensity distribution and the phase velocity distribution of a slit in laser beams with different parameters are analyzed. Using three-dimensional test particle simulation, the laser beam with a slit induced acceleration of electrons with different initial momenta is investigated. Contrary to anticipation, the maximum net energy gain is not monotone increasing as the incoming momentum increasing. Based on the field structure and analysis, we gave an explanation for this.

This paper deals with the linear dynamic responses of beams with a flexible support under a moving load with a constant speed. The entire system is modeled as a two-span beam and each span of the continuous beams is assumed to obey the Euler-Bernoulli beam theory. Considering the compatibility requirements on the flexible constraint, the relationships between two segments can be obtained. By using a transfer matrix method, the characteristic equation of the entire system can then be determined. The forced responses of the system under a moving load can then be obtained through modal expansion theory. Some numerical results are presented to the effects of support stiffness and the different speeds of the moving load.