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Arcs extending part way across a thin layer of damp powder have been studied. The powder consisted of alumina with 0.05% sodium chloride, and formed a thin layer on a glass strip. These partial arcs were formed if the applied voltage was above a certain minimum and below the voltage for complete flashover. They appeared to be initiated by localized low-current surface breakdowns (scintillations) which could develop into partial arcs having currents of several milli-amperes. It was found that, using Warrington's expression for the voltage drop along an arc, a good correlation was found with the measured arc parameters. However this left a current in the remaining part of the thin layer of damp alumina which could not be explained by ohmic conduction, being too high by more than two orders of magnitude. It appears that 'ionization conduction' must be invoked to explain the very much higher apparent conduction occurring in the thin alumina layer. This 'ionization conduction' is a phenomenon in which multiple series-parallel micro-flashovers occur between and over the granules in a granulated material. Index Terms--Arc discharges, pollution, insulators, ionization conduction.

The steady-state and transient responses of circular grating-coupled distributed feedback (CGC DFB) lasers were analyzed with a computer model. The model solved the time-dependant coupled-mode equations and carrier rate equation with the use of a modified time-domain finite-difference method.

The lasing characteristics of external optical feedback (EOFB)-driven 1.55 m antiresonant reflecting optical waveguide (ARROW) vertical-cavity surface-emitting lasers (VCSELs) are evaluated. Findings reveal the achievement of stable single-mode chaotic light sources from EOFB driven ARROW VCSELs with large core radius.

An axisymmetric lattice Boltzmann model is described that has solved the complete nonlinear Poisson-Boltzmann equation to obtain the electric potential distribution in the electrolytes and another axisymmetric lattice Boltzmann model is used for solving the velocity field. The results have shown that the microannular electro-osmotic flow has displayed much difference from the planar flow and the non-Newtonian rheology has a major effect on the flow behavior.

The application of the different hybrid surface-plasmon and Fabry-Perot modes in the generation of the extraordinary transmission of the extremely narrow slits is analyzed.

A theoretical model is developed for analyzing the modal characteristics of a second-order concentric-circular metal grating surface-emitting distributed-feedback (DFB) laser operating at terahertz regime. The effect of grating duty cycle on the resonant conditions and transverse distributions of the diffracted fields are examined and the results have shown that the interference of the diffracted cylindrical waves has formed quasisymmetric and quasiantisymmetric modes.