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...

In this study, Polyaniline molecule (emeraldine base) is modeled as a molecular wire and the effects of the metal/molecule coupling strength and the molecule length on the current-voltage (I-V) characteristics are numerically investigated. Using a tight-binding Hamiltonian model, the methods based on Non-equilibrium Green’s function theory, Landauer formalism and Newns-Anderson model, our calcu...

this paper presents a mathematical model for the vibration analysis of a three-component piezoelectric force sensor. the cubic theory of weakly nonlinear electroelasticity is applied to the model for describing the electromechanical coupling effect in the piezoelectric sensing elements which operate in thickness-shear and thickness-stretch vibration modes. hamilton's principle is used to d...

In this research, using the Modified Compression Field Theory (MCFT), a new model is proposed to predict the behavior of reinforced concrete coupling beams. The model is able to consider the effects of shear and axial forces and bending moment, simultaneously. The proposed model includes a nonlinear shear spring, an axial spring and some nonlinear springs for considering bending deformations. I...

the semi-classical model of atom-field interaction has been fully studied for some multilevel atoms, e.g. vee, l, cascade x , y, and inverted y and so on. this issue is developed into the full-quantum electrodynamics formalism, where the probe and coupling electromagnetic fields are quantized. in this article, we investigate the full-quantum model of absorption and dispersion spectrum of trappe...

The ability to move in complex environments is one of the most important features of humans and animals. In this work, we exploit a bio-inspired method to generate different gaits in a bipedal locomotion system. We use the 4-cell CPG model developed by Pinto [21]. This model has been established on symmetric coupling between the cells which are responsible for generating oscillatory signals. Th...

this study is concerned with the prediction of particles’ velocity in a dilute turbulent gas-solidboundary layer flow using a fully eulerian two-fluid model. the closures required for equationsdescribing the particulate phase are derived from the kinetic theory of granular flows. gas phaseturbulence is modeled by one-equation model and solid phase turbulence by mlh theory. resultsof one-way and...

In this paper a new procedure for designing forward-wave directional couplers using periodic shunt short circuited stubs is proposed. A new type of cell using these stubs, which enlarge the phase difference between even- and odd modes of a uniform microstrip coupled line is introduced. Using the equivalent circuit model for even- and odd-modes of the proposed cell, the elements of the  ABCD tra...

In this study, a fractal, Y-shaped dual-mode resonator bandpass filter (BPF) with input-output cross-coupling is introduced. A parallel-coupling feed structure with a cross coupling has been used to generate two transmission zeroes (TZs) near the lower and upper cutoff frequency that can effectively improve the passband edge selectivity. Also, a fractal shaped based on conventional diamond and ...