With the recent rediscovery of slowand fast-light effects, there has been much interest in pulse propagation phenomena that lead to apparently superluminal pulse transmission. This raises immediate questions about causality and special relativity violations and elicits curiosity about the physical mechanisms responsible for these effects. This thesis will address these issues theoretically and ...

The Petrova (2000) model to calculate pulse profiles is extended to a variable emission height model to make it physically self-consistent. In this context variable means that the emission height is no longer considered to be the same for different magnetic field lines. The pulse profiles calculated using this new model seem to be less realistic due to a focusing effect and cannot be used to fi...

background: to manage relapsing‑remitting multiple sclerosis (ms) in the course of acute exacerbations, methylprednisolone (mp) (medrol or solu‑medrol), has the ability to lock the injured blood‑brain barrier and decrease irritation in the central nervous system. the aim of this preliminary study was to investigate the frequency and time interval related to mp pulse therapy in patients with ms....

The main purpose of pulse-width –modulation technique for power inverters is to control the output voltage. The most familiar techniques: uniform-pulse-width-modulation and sinusoidal-pulsewidth-modulation. This paper proposes new techniques for improving the inverter performance. The methods are based on pulse-width technique. A variation of pulse-widths for the middle and boundary pulses is i...

The effect of a proper shaping of the temporal envelope of isolated pulses in slow-light systems based on stimulated Brillouin scattering in optical fibers is studied and experimentally demonstrated. The pulse shape can be optimized to lead to a substantial enhancement of the delaying effect. The spectrum of the optical pulses is engineered so that the spectral width of the pulse is minimized w...

With their short nanosecond pulse durations, Qswitched lasers have revolutionized the treatment of tattoos [1-3]. Nevertheless, the mechanisms for clinically observed tattoo clearance are still not well understood. Two mechanisms have been proposed: a) a thermal effect where tattoo particles are heated to sufficiently high temperatures to cause chemical changes within the particles and the surr...

A technique of laser pulse shaping was developed for low-emittance electron beam generation in a photocathode RF gun. The emittance growth due to space charge and RF effects in the RF gun was experimentally investigated with square and gaussian temporal laser pulse shapes. It is found that the square pulse shaping is a useful tool for both the reduction of nonlinear space charge force and the c...

The interaction of an optical pulse with a quantum well saturable absorber is simulated using a semi-classical two-level-atom model which has been modified to approximate spectral hole burning in the carrier distribution. Saturable absorption behaviour is examined in the limit where pulse duration approaches the carrier-carrier scattering time. For long pulses bleaching dominates the absorber r...