Effect of high energy electron irradiation on the electromechanical properties of poly (vinylidene fluoride-trifluorethylene) 50/50 and 65/35 copolymers

High energy electron irradiation with a broad range dosage was carried out on poly(vinylidene fluoride trifluorethylene) copolymer 65/35 mol% and 50/50 mol% films at different temperatures from room temperature to a temperature close to the melt temperature. The effect of irradiation on the properties of the films, such as electric field-induced strain, dielectric and polarisation behaviors, and mechanical modulus, is presented. The irradiated films can exhibit a very large electric field-induced strain, more than 4.5% longitudinal strain, and 3% transverse strain. The transverse strain of the stretched film can compare with the longitudinal strain; that of the unstretched film is much smaller than the longitudinal strain. With regard to the dielectric and polarization behaviors, we found that irradiation changes the copolymer from a typical ferroelectric to a relaxor ferroelectric in which the behavior of microregions under the electric field plays the key role. Between the two copolymers studied, we found that the 65/35 copolymer is preferred for both longitudinal and transverse strain generation. A model is proposed to explain the experimental results that the amplitude of the charge electrostrictive coefficient (Q) increases with decreasing crystallinity.     

Design of all-optical JK,SR and T flip-flops using micro-ring resonator-based optical switch

In the present communication, all-optical clocked J–K flip-flop is proposed and described using silicon waveguide-based optical micro-ring resonator (OMRR). We have used two optical pump signals representing the two operands (J and K) of the logical operation to modulate the OMRRs under low pump power condition. A theoretical model of the proposed J–K flip-flop and hence S–R and T flip-flop are developed using micro-ring resonator through pump–probe configuration. Numerical simulation results for clocked flip-flop circuits verifying the proposed method are given in this paper. We identified a combination of feasible OMRR radius and detuning through numerical simulation which allows analyzing the system performance of the scheme such as maximum amplitude difference between marks \((\hbox {AD}_{1,\mathrm{{max}}})\), between spaces \((\hbox {AD}_{0,\mathrm{{max}}})\) and between marks and spaces \((\hbox {AD}_{1/0,\mathrm{{max}}})\), which confirm the feasibility of the flip-flop design. A maximum buildup factor of 19.57 is achieved at an optimized coupling coefficient of 0.22.