Interesting effects of the piezoelectric and internal electric fields on the band gap of InAs/GaAs/AlGaAs:δ-Si HEMTs

The quantum confined Stark effect (QCSE) has been investigated in detail in GaAs/AlGaAs and InAs/GaAs/AlGaAs HEMTs structures grown by molecular beam epitaxy on (1 0 0) oriented GaAs substrates. A power dependent photoluminescence (PL) study allowed to highlight the QCSE caused by the internal electric field in the GaAs channel then a piezoelectric field reinforce the red-shift. Increasing the Si-δ-doping leads to; first a red-shift then a blue shift at high excitation power due to the stabilize quantum well structures tendency and the saturation phenomenon. The HEMT band structures and the theoretical activated electron densities at 10 K have been studied using the finite difference method and the simultaneously solve of the Schrödinger and the Poisson equations written within the Hartree approximation

Organizational Ethics and Its Role in Dealing with Work Stresses of the Working Staffs in the Directorate of Education at AL-Karkh the Second from Their Point of View

   Institutions play a major role in the positive and negative impact on employees, as chronic work stress is an important contributor to the poor well-being of employees, as it suffers from nearly the majority of the workforce in the world, due to its impact on the reputation of the institution, its operations and its relationship with its customers, and that one of the reasons for the emergence of cases of stress The workplace is the ethical behavior of employees.    So, the research aims to: building a measure of organizational ethics in DEK2nd from the point of view of its cadres. Building a measure of the work stresses of working in DEK2nd from their point of view. Identifying the level of organizational ethics practice in DEK2nd from the point of view of its cadres. Identifying the level of work stresses facing the working staffs in DEK2nd from their point of view. Identifying the level of work stresses facing the working staffs in DEK2nd from their point of view.    The researcher used the descriptive approach using both survey and correlation methods, the research community included (275) employees from the working staffs in DEK2nd, The sample of the exploratory study, the preparation sample, and the application sample were chosen randomly, with (5, 162, and 108) employees, respectively, in order to collect information, a measure of organizational ethics was built, and the researcher also built a measure of job pressures, And then they were applied after the scientific conditions were met them. The data were processed statistically, using the arithmetic mean, percentage, simple correlation coefficient, Alpha chronbach coefficient, and simple and gradual linear regression equations. The researcher concluded several direct ones:The researchers verified the effectiveness of the organizational ethics scale in DEK2nd from the point of view of its staff, after reaching its preparation according to scientific procedures. The researchers verified the effectiveness of the work stress scale in DEK2nd from the point of view of its staff, after reaching its preparation according to scientific procedures. The Directorate of Education at AL-Karkh the second has an average level of organizational ethics from the point of view of its staff. The staff of DEK2nd have a medium level of working stress from their point of view

Improved twelve sectors DTC strategy of induction motor drive using Backstepping speed controller and P-MRAS stator resistance identification-design and validation

The Direct Torque Control (DTC) was previously designed to achieve high performance of induction motor (IM) by accurately and independently controlling its flux and torque. However, this classical DTC generates several disadvantages such as strong fluctuations in the torque and stator flux as well as quite significant switching losses. For these reasons, many modern techniques have been proposed in the literature to improve it. On the other hand, as the inadequacy of the parameters seriously affects the efficiency and stability of the induction motor, it is paramount to accurately estimate the stator resistance, for this, robust observers are necessary suggested to be employed. This paper proposes developed structure of DTC strategy using twelve sectors combined with Backstepping speed regulator for the external loop and robust model reference adaptive system based on active power principle to estimate the stator resistance. In addition, several simulations under Matlab/Simulink and experiment results using the dSPACE DS1104 board are discussed to confirm improvements in control and speed estimation

Enhancement of the photoluminescence property of hybrid structures using single-walled carbon nanotubes/pyramidal porous silicon surface

This work presents additional physical results about the enhancement of the photoluminescence property of hybrid structures using single walled carbon nanotubes/pyramidal porous silicon surface, in comparison with what has already been published on these structures in terms of synthesis conditions and FTIR investigations as reported recently by the same authors in Journal of Alloys and Compounds 694 (2017) 1036 1044. Herein, the effect of the single walled carbon nanotubes (SWCNTs) layer on the optical properties of pyramidal Porous Silicon (pPSi) in hybrid SWCNTs/pPSi structure synthetized by chemical and electrochemical etching of silicon wafer was studied. Using both scanning electron mi croscopy (SEM), SWCNTs formed a thin film on pPSi surface and they are partly embedded in its pores. An analysis of Raman spectra for the realized structures confirmed the passivation of pPSi surface by SWCNTs film. The surface bond configurations were also monitored. Moreover, SWCNTs modified Pho toluminescence (PL) spectrum of pPSi by shifting PL peaks towards high energies, showed that the defect created in the materials can result in an efficient and stabilized photoluminescence response on Silicon (Si)