The purpose of our work is to report a theoretical study of electrons tunneling through semiconductor superlattice (SSL). The (SSL) that we have considered is (GaN/AlGaN) system within the energy range of ε < Vo, ε = Vo and ε > Vo, where Vo is the potential barrier height. The transmission coefficient (TN) was determined using the transfer matrix method. The resonant energies are obtained from the T (E) relation. From such system, we obtained two allowed quasi-levels energy bands for ε < VO and one band for ε VO.
An electrolytic process for the removal of Zn(II) from aqueous solution using a parallel amalgamated copper screens cathode operated in the flow through mode is proposed. The current-potential curves recorded at a rotating amalgamated copper disc electrode were used to determine diffusion coefficient of Zn(II). The performance of electrolytic reactor was investigated by using different flow rates at initial zinc ion concentration(48 mg/L). Taking into account the residential Zn(II) concentration, the best results were obtained for cathode potential of (-1.35 V vs. SCE) at flow rate (320 L/h). Zinc ion concentration was found to decrease from 48 mg/L to 1 mg/L during 120 min. of electrolysis. The experimental data are well correlate
... Show MoreBackground: Although ultrasonography (US) continues to be the primary imaging modality used to identify and characterize adnexal masses, but certain conditions that hinder accurate ultrasound examination, such as obesity, may be indications for magnetic resonance (MR) imaging, for the assessment of complex and indeterminate ovarian masses.
Objective: to assess the ability of MRI to characterize sonographically indeterminate adnexal masses.
Patients and methods: A prospective study of 89 cases with sonographically indeterminate adnexal mass underwent pelvic MRI conducted in X-ray institute in medical city in Baghdad during period from October 2011 to January 2013 & the results compared to the final diagn
In this paper, an experimental study has been conducted regarding the indication of resonance in chaotic semiconductor laser. Resonant perturbations are effective for harnessing nonlinear oscillators for various applications such as inducing chaos and controlling chaos. Interesting results have been obtained regarding to the effect of the chaotic resonance by adding the frequency on the systems. The frequency changes nonlinear dynamical system through a critical value, there is a transition from a periodic attractor to a strange attractor. The amplitude has a very relevant impact on the system, resulting in an optimal resonance response for appropriate values related to correlation time. The chaotic system becomes regular under
... Show MoreThe present work aims to improve the flux of forward osmosis with the use of Thin Film Composite membrane by reducing the effect of polarization on draw solution (brine solution) side.This study was conducted in two parts. The first is under the effect of polarization in which the flux and the water permeability coefficient (A) were calculated. In the second part of the study the experiments were repeated using a circulating pump at various speeds to make turbulence and reduce the effect of polarization on the brine solution side.
A model capable of predicting water permeability coefficient has been derived, and this is given by the following equations:
Z=Z0 +C.R.T/9.8(d2/D2+1) [Exp. [-9.8(d
Silver nanoparticles (Ag-NPs) have been prepared using the electro-chemical
method. The experimental setup of this technique consist of two electrodes of pure
silver (99.2 %), the applied voltage on the electrodes is 20 V and the current through
the colloidal was about 0.4 Amp. The silver nanoparticles crystallization has been
studied; the crystalline structure appears Face center Cubic. The optical properties of
silver nanoparticles are strongly affected by the Local Surface Plasmon Resonance
(LSPR). The wavelength of maximum absorption band for an Ag NPs have a range
(~350nm-550nm).
Optical fiber biomedical sensor based on surface plasmon resonance for measuring and sensing the concentration and the refractive index of sugar in blood serum is designed and implemented during this work. Performance properties such as signal to noise ratio (SNR), sensitivity, resolution and the figure of merit were evaluated for the fabricated sensor. It was found that the sensitivity of the optical fiber-based SPR sensor with 40 nm thick and 10 mm long Au metal film of the exposed sensing region is 7.5µm/RIU, SNR is 0.697, figure of merit is 87.2 and resolution is 0.00026. The sort of optical fiber utilized in this work is plastic optical fiber with a core diameter of 980 µm, a cladding of 20μm, and a numerical aperture of 0.
... Show MoreOur research sheds light on one of the most important aspects of David Grossman's play, "Ricky's Garden, גן ריקי " which is characterized by its realistic portrayal of characters. Grossman gradually moves towards the inner awareness of his characters, expressing their emotions and thoughts through conversations and emotional conflicts, referring to their past and rooted background. Grossman transformed the main subject of his play (psychological depth) into a presentation and arrangement of all the elements of the play in a way that expresses emotional nature more powerfully by each child in the garden. This is reflected in their actions and words, making Grossman's works suitable for study and always of interest to specialized resear
... Show MoreIn this work, a pollution-sensitive Photonic Crystal Fiber (PCF) based on Surface Plasmon Resonance (SPR) technology is designed and implemented for sensing refractive indices and concentrations of polluted water . The overall construction of the sensor is achieved by splicing short lengths of PCF (ESM-12) solid core on one side with traditional multimode fiber (MMF) and depositing a gold nanofilm of 50nm thickness on the end of the PCF sensor. The PCF- SPR experiment was carried out with various samples of polluted water including(distilled water, draining water, dirty pond water, chemical water, salty water and oiled water). The location of the resonant wavelength peaks is seen to move to longer wavelengths (red shift)
... Show More. Surface Plasmon Resonance (SPR) technology has been adapted to produce a sensitive optical sensor and Biosensor applications. Simulation analysis ( in Matlab) has been made for SPR for gold (Au) layer with thickness (40 nm) and Polyvinyl Alcohol (PVA) polymer with various thickness (10, 20, 30, 40, 50, 60, 70 and 80 nm) deposited on glass prism type D-ZLAF50_Dense lanthanum flint. The sensitive layer was air (n=1). The analysis was taken for different wavelengths from Ultra-Violet wavelength 100 nm to Near Infra- Red wavelength 1000 nm. The properties of θSPR have been calculated from plotted reflectance against incident angle θincid.. The SPR sensitivity (S) was calculated. The results give efficient detection in chan
... Show MoreIn this work, the effects of size, and temperature on the linear and nonlinear optical properties in InGaN/GaN inverse parabolic and triangular quantum wells (IPQW and ITQW) for different concentrations at the well center were theoretically investigated. The indium concentrations at the barriers were fixed to be always xmax = 0.2. The energy levels and their associated wave functions are computed within the effective mass approximation. The expressions of optical properties are obtained analytically by using the compact density-matrix approach. The linear, nonlinear, and total absorption coefficients depending on the In concentrations at the well center are investigated as a function of the incident photon energy for different
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