ABSTRACT:The dynamic mechanical properties of epoxy composites filled with different amounts of quartz powder were investigated. The storage modulus and loss tangent were measured at frequencies between 7.8 and 323 Hz from room temperature up to 460 K. The influence of the filler content on the temperature and frequency behavior of the dynamic mechanical properties is discussed and explained in terms of models presented in the literature. In particular, the dependence of the composite damping with the quartz content is explained with regard to damping due to particleparticle and polymer-particle interaction. Also, the glasstransition temperature as a function of filler content was obtained and was related to the results obtained for the apparent activation energies of the ␣ relaxation, which were estimated with the Williams, Landel, and Ferry equation.

We study, experimentally and numerically, the increase of the stimulated Brillouin scattering (SBS) threshold in dispersion-shifted fibers (DSFs) by applying three different tensile-strain distributions. The best results are obtained with a 40-step stair-ramp distribution, for which we demonstrate a 8-dB SBS threshold increase in a 580-m DSF. The Brillouin frequency is observed to shift as a function of the strain at a rate of 0.464 GHz/%. We discuss the potentials and drawbacks of this technique for application in nonlinear devices.

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