67,653 research outputs found
Laser ignition of an optically sensitised secondary explosive by a diode laser
As a green technology, laser ignition of a relatively insensitive secondary
explosive has been experimentally investigated. The explosive, hexanitrostilbene
(HNS), was doped with one of two optical sensitizers, carbon black or a laser
absorbing dye, and a continuous-wave (CW) infrared diode laser was used as the
igniting source. The ignition sensitivities of HNS with each of the two optical
sensitizers were analysed and compared in terms of: optical power threshold for
ignition, ignition delay and full burn delay at various laser powers. The results
have shown that both the chemical dye and carbon black optically sensitize
the explosive with similar efficiencies. In contrast to the carbon black, the dye
provides wavelength specificity and selectivity in the laser ignition process and its
solubility in some specific solvents improves the coating of the explosive material.
It was therefore concluded that the laser absorbing dye is a better candidate for
optical sensitization in laser ignition than the commonly used carbon black. The
combination of laser ignition sensitivity with wavelength selectivity potentially
offers higher reliability and safety at a low optical power for future ignitors of
secondary explosives
Control of lasing in fully chaotic open microcavities by tailoring the shape factor
We demonstrate experimentally that lasing in a semiconductor microstadium can
be optimized by controlling its shape. Under spatially uniform optical pumping,
the first lasing mode in a GaAs microstadium with large major-to-minor-axis
ratio usually corresponds to a high-quality scar mode consisting of several
unstable periodic orbits. Interference of waves propagating along the
constituent orbits may minimize light leakage at particular major-to-minor-axis
ratio. By making stadium of the optimum shape, we are able to maximize the mode
quality factor and align the mode frequency to the peak of the gain spectrum,
thus minimizing the lasing threshold. This work opens the door to control
chaotic microcavity lasers by tailoring the shape factor
Recursive Approximation of the High Dimensional max Function
An alternative smoothing method for the high dimensional max functionhas been studied. The proposed method is a recursive extension of thetwo dimensional smoothing functions. In order to analyze the proposedmethod, a theoretical framework related to smoothing methods has beendiscussed. Moreover, we support our discussion by considering someapplication areas. This is followed by a comparison with analternative well-known smoothing method.n dimensional max function;recursive approximation;smoothing methods;vertical linear complementarity (VLCP)
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