We studied the electronic energies and phonon frequencies of polydiacetylene 4-BCMU thin films at high pressures up to 50 kbar using Raman scattering under preresonant and resonant conditions. Pressure-induced changes in the resonant Raman scattering (RRS) include (1) hardening of the most strongly coupled phonon frequencies, (2) dispersion of the RRS frequencies with the laser excitation coL, ...

Original scientific paper This study proposes an artificial neural network (ANN) model in order to approximate the resonant frequencies of equilateral triangular patch antennas. The neural network structure applied here is trained and tested for both single-layer and double-layer antennas. It is shown upon experiment that the resonant frequencies obtained from the neural network are both more a...

Power system overvoltages due to switching, lightning and other disturbances are the main problem for designers of the power transformers. Once some frequencies of the incoming surges match with some of the natural frequencies of transformer winding, the resonance phenomenon is expected in transformer winding. The resonant overvoltages may destroy the insulation between turns and cause to insul...

We investigate numerically the limits of the resonant magnetic response with a negative effective permeability mu(eff) for single-ring multicut split-ring resonator (SRR) designs up to optical frequencies. We find the breakdown of linear scaling due to the free electron kinetic energy for frequencies above approximately 100 THz. Above the linear scaling regime, the resonance frequency saturates...

The peculiarities of external synchronization of a resonant limit cycle on a torus are studied in an autonomous oscillator of quasiperiodic oscillations with two basic frequencies. We show numerically and experimentally that in the resonance conditions the synchronization effect takes place only at one of the two basic frequencies of the system, while the oscillations at the second basic freque...

We consider two electric RLC resonance networks that are equivalent to quantum billiards. In a network of inductors grounded by capacitors, the eigenvalues of the quantum billiard correspond to the squared resonant frequencies. In a network of capacitors grounded by inductors, the eigenvalues of the billiard are given by the inverse of the squared resonant frequencies. In both cases, the local ...

We propose an analytical theory which predicts that Converging Plasmon Resonance (CPR) at conical nanotips exhibits a red-shifted and continuous band of resonant frequencies and suggests potential application of conical nanotips in various fields, such as plasmonic solar cells, photothermal therapy, tip-enhanced Raman and other spectroscopies. The CPR modes exhibit superior confinement and ten ...

This paper presents a dual band aperture coupled stacked microstrip antenna with the introduction of an air gap 3 mm between the ground plane and the upper layer substrate for WLAN applications. The nominal antenna has – 10 dB return loss bandwidth of 134.8 MHz and 384.9 MHz at lower band resonant frequency of 3.905 GHz and upper band resonant frequency of 5.36 GHz respectively. The gain of the...

We propose a method to obtain the resonance frequencies of coupled optical modes for a stack of two periodically corrugated slabs. The method is based on the modes in each slab, which are derived by the Fourier modal method in combination with the optical scattering matrix theory. We then use the resonant mode approximation of the scattering matrices to develop a linear eigenvalue problem with ...

We report on the direct visualization of chirality changes in carbon nanotubes by mapping local changes in resonant RBM phonon frequencies with an optical resolution of 40 nm using near-field Raman spectroscopy. We observe the transition from semiconducting-to-metal and metal-to-metal chiralities at the single nanotube level. Our experimental findings, based on detecting changes in resonant RBM...