We consider harmonic generation by atoms exposed to an intense laser pulse of a few femtoseconds. Our results, obtained by solving numerically the corresponding 3-dimensional time-dependent Schrodinger equation, demonstrate that the harmonic spectra are extremely sensitive to the phase of the laser field. Depend- ing on this phase, the harmonics in the cutoff are resolved or not resolved. The position of the cutoff itself varies with the phase and the so-called “plateau” region exhibits two well-distinct parts: a series of well-defined har- monics followed in the high-frequency region by a series of broad peaks which are not separated any more by twice the laser field frequency. These results are explained in terms of both quantum and classical dynamics. We also show that this phase sensitivity may be exploited in order to probe the phase of the electric field of an ultrashort laser pulse in a single shot experiment. Our discussion about this new method of diagnosis takes into account propagation effects.

This paper deals with a particular case of implementing surge arresters with an external gap to cope with the high failure rate of a 110 kV overhead line. Optimization of the number of arresters and their installation location was based on lightning performance computation which is also described.

Taking advantage of GSM's elaborated mobility managementand its intemational roaming capability, the IntemationalUnion of European Railroad Operators (UJC) has decidedto build a supra-national rail radio network based on enhancedGSM technology.In this pape1; some implemmtation aspects specific to railroadradio environment resulting from the effects of vehiclespeed - in particular Doppler shift - are discussed, and an'off-line' algorithm for the traffic handover is proposed, whichoffers bel/er radio link reliability and less critical timing constraintsthan conventional handover schemes. More reliablehandover is of vital significance in the case of high-speed trainssince the radio link is supposed to cany the automatic controlsignals (ATC), too.