A numerical computation for determination transmission coefficient and resonant tunneling energies of multibarriers heterostructure has been investigated. Also, we have considered GaN/Al0.3Ga0.7N superlattice system to estimate the probability of resonance at specific energy values, which are less than the potential barrier height. The transmission coefficient is determined by using the transfer matrix method and accordingly the resonant energies are obtained from the T(E) relation. The effects of both well width and number of barriers (N) are observed and discussed. The numbers of resonant tunneling peaks are generally increasing and they become sharper with the increasing of N. The resonant tunneling levels are shifted inside the well by increasing the well width and vice versa. These features and the transmission coefficient as a function of incident energetic particles play an important role in fabrication of high speed devices and a good factor for determination the peak-to-valley ratio of resonant tunneling devices respectively.
Abstract: This study was aimed to investigate the effect of two doses of pregabalin (PGB) on hormonal level and sexual activity in female albino rats. Ninety female rats with age (9-10 weeks) and weight (200±20 g) were divided into three major groups of thirty rats. First group was considered as control G1, the second G2 and third G3 groups were exposed to PGB into two doses 150, and 300 mg/kg body weight per day respectively. Each major group was divided into three subgroups (subgroup A, B, and C of each has ten rats), the treatments last for one month for subgroup A, two months for subgroup B, and three months for subgroup C. Five rats from each subgroup were placed separately into two breeding cages with two isolated males and wait
... Show MoreThe standard formulation of Wave Intensity Analysis (WIA) assumes that the flow velocity (U) in the conduit is <;<; the velocity of propagation of waves (c) in the system, and Mach number, M=U/c, is negligible. However, in the large conduit arteries, U is relatively high due to ventricular contraction and c is relatively low due to the large compliance; thus M is > 0, and may not be ignored. Therefore, the aim of this study is to identify experimentally the relationship between M and the reflection coefficient in vitro. Combinations of flexible tubes, of 2 m in length with isotropic and uniform circular cross sectional area along their longitudinal axes, were used to present mother and daughter tubes to produce a range of reflection coeffic
... Show MoreLow-dimensional materials have attracted significant attention in developing and enhancing the performance of quantum well lasers due to their extraordinary unique properties. The optical confinement factor is one of the most effective parameters for evaluating the optimal performance of a semiconductor laser diode when used to measure the optical gain and current threshold. The optical confinement factor and the radiative recombination of single quantum wells (SQW) and multi-quantum wells (MQW) for InGaAsP/InP have been theoretically studied using both radiative and Auger coefficients. Quantum well width, barrier width, and number of quantum wells were all looked at to see how these things changed the optical confinement factor and
... Show MoreAbstract
The research aims to determine the role of the efficiency of Human Resources Information System in the effectiveness of Employees Performance Appraisal System in the Ministry of Higher Education and Scientific Research / Center for the ministry, it was touching the researchers need the ministry to devise methods that employ outputs Human Resources Information System in the organization surveyed for the development of methods and levels of process evaluate the performance of its employees, in order to identify the extent of the role played by human resources information system in the process of assessing the performance of employees, we raised the question of the President as follows:
... Show MoreThe bubble columns are widely used as a two or three phase reactor in industrial chemical process such as absorption, biochemical reactions, coal liquefaction, etc. To design such a column, two main parameters should be taken in consideration, the gas hold-up (), and the liquid phase mass transfer coefficient KLa. The study includes the effect of gas velocity and the addition of alcohols on gas hold-up and mass transfer coefficient in bubble column with draught tube when the length of the column is 1.5m and the ratio of the draught tube diameter to the column diameter equals 0.5 and the air dispersion into the base of the draught tube using a multi hole tuyere is equivalent to a diameter of 0.15 mm and
... Show MoreThe purpose of this paper is to depict the effect of adding a hydraulic accumulator to a hydraulic system. The experimental work includes using measuring devices with interface to measure the pressure and the vibration of the system directly by computer so as to show the effect of accumulator graphically for real conditions, also the effects of hydraulic accumulator for different applications
have been tested. A simulation analysis of the hydraulic control system using MATLAB.R2010b to study was made to study the stability of the system depending on the transfer function, to estimate the effect of adding the accumulator on stability of the system. A physical simulation test was made for the hydraulic system using MATLAB to show the ef
The aim of this research is to study the factors affecting drag coefficient (C d ) in
non-Newtonian fluids which are the rheological properties ,concentrations of non-
Newtonian fluids, particle shape, size and the density difference between particle and
fluid .Also this study shows drag coefficient (C d ) and particle Reynolds' number (Re
P ) relationship and the effect of rheological properties on this relationship.
An experimental apparatus was designed and built, which consists of Perspex pipe
of length of 160 cm. and inside diameter of 7.8 cm. to calculate the settling velocity,
also electronic circuit was designed to calculate the falling time of particles through
fluid.
Two types of solid particles were
A field experiment was carried out during the seasons 2016 and 2017 in the farm of the Department of Field Crops Science, College of Agricultural Engineering Sciences-University of Baghdad to evaluate the effect of(Aminopyralid + Flurasulam, Coldinafop-propargyl and Flucarbazone-sodium) herbicides and seeding rate (100, 125 and 150) Kg.ha-1 and the interaction between them in growth characteristics, grain and yield components in wheat (Var. IPA99). The results showed that herbicides used were significantly efficient in studied characteristics compared to weedy treatment. Herbicide Flucarbazone-sodium gave higher weed control after 60 and 90 days of spraying the he
The physical behavior for the energy distribution function (EDF) of the reactant particles depending upon the gases (fuel) temperature are completely described by a physical model covering the global formulas controlling the EDF profile. Results about the energy distribution for the reactant system indicate a standard EDF, in which it’s arrive a steady state form shape and intern lead to fix the optimum selected temperature.