a complete linear theory in four dimensional space-time is constructed for propagation and coupling of electromagnetic waves in the most general case, i.e. media where all three space directions are in homogeneous and where temporal changes, anisotropy and absorbtion are also included. the only condition is that the properties of the medium should be slowly varying, although it is assumed that ...

this study introduces the differential transform method (dtm) to analyse the free vibration response of a rotating, closed section, composite, timoshenko beam which features material coupling between flapwise bending and torsional vibrations due to ply orientation. the governing differential equations of motion are derived using hamilton’s principle and solved by applying dtm. the natural frequ...

the synthesis, spectroscopy and magnetic characterization of five new dinuclear copper(ii) complexes are described. all five compounds have the general formula [cu2(l)4(o-r)2](cl)2 or [cu2(l)2(cl)2](cl)2, in which r = ch3 or h, l=2, 3 or 4-pyridinemethanol as l2, l3 or l4, respectively. the title compounds consist of dinuclear units with bridging methoxo groups in [cu2(l4)4(o-ch3)2](cl)2, hydro...

objective: electroencephalogram is a reliable reflection of many physiological factors modulating the brain. the bispectrum is very useful for analyzing non-gaussian signals such as eeg, and detecting the quadratic phase coupling between distinct frequency components in eeg signals.the main aim of this study was to test the existence of nonlinear phase coupling within the eeg signals in a certa...

in this paper, effects of the structural parameters on the optical characteristics of an add-drop filter, consisting of two straight waveguides and a micro-ring resonator (mrr), have been investigated. in this research, effects of mrr radius, the width of mrr and waveguide and the gap between mrr and waveguide, on free spectral range (fsr) and coupling coefficient have been studied. it is found...

designing a power splitter with five ports has been shown in this article. in order to prevent the direct coupling between waveguides, a t-shaped structure with an appropriate distance has been used. the coupling between the parallel photonic crystal waveguides is based on multimode interference, while selecting the output efficiency is performed by setting the refractive coefficients and radiu...

zinc oxide nano-particles with the average diameter of about 25 nm were modified with different mole ratios of trimetoxyvinyl silane (tmvs) and oleic acid, as coupling agents, in order to modify their surface properties and render them more hydrophobic. then, dispersibility of the surface modified nano-particles was examined in some monomers with different levels of hydrophobicity, including me...

on the source of plasma density and electric field perturbations in pmse and pmwe regionspolar mesospheric summer/winter echoes (pmse/pmwe) are very strong radar echoes produced by ionospheric electron density fluctuations at half the radar wavelength. the main focus of this paper is the altitude range 80 to 90 km in summer and altitude range 65-86 km in winter in the polar mesosphere . this pa...