http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Brahim Brahmi,Ibrahim El Bojairami,Maarouf Saad,Mark Driscoll,Samir Zemam,Mohamed Hamza Laraki 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.1
This paper presents the design and validation of a new adaptive variable gain reaching law, integrated with sliding mode control (SMC), to control perturbed and unperturbed nonlinear systems. The novelty behind this law stems from its capability to overcome the main limitations involved with SMC. In contrast to existing reaching laws, system’s performance can be substantially enhanced via this law, with signifi cant reduction in the chattering phenomenon, along ensuring rapid convergence time of system’s trajectories towards equilibrium. The designed law not only integrates the features of both the exponential reaching law (ERL) and the power rate reaching law (PRL), but also overcomes their limitations. Simulation and comparison studies against ERL and PRL were carried out to validate the eff ectiveness and advantages of the proposed reaching law scheme (Proposed-RL). Furthermore, controlled experimental investigations were conducted using an exoskeleton robot (ETS-MARSE) to validate the scheme in real-time.
Brahim Gaies,Mahmoud-Sami Nabi 세종대학교 경제통합연구소 2019 Journal of Economic Integration Vol.34 No.3
This study examines how external financing (EF) affects growth in developing countries by distinguishing between two forms of external financing: debt and foreign direct investment (FDI). We show that both types favor growth by boosting investment through the credit channel. However, excessive external debt increases vulnerability to financial crises. Contrariwise, FDI plays an amortizing role by reducing a crisis’ effects. The empirical evidence confirms these results and demonstrates that, despite the more secure nature of FDI, mixed financing (debt and FDI) remains more profitable for developing countries because of the inverted U-shaped growth effect of the FDI-to-debt ratio. Moreover, exchange rate stability decreases vulnerability to financial crises, whereas higher stability turns into exchange rate rigidity and thus increases crisis occurrence.
Magnetic Anisotropy of Pd/Co/Pd Ultrathin Film: Interface Vacancy Defect and O Diffusion Effect
Brahim Marfoua,Jisang Hong 한국자기학회 2021 Journal of Magnetics Vol.26 No.3
Using first principles calculation, we investigated the magnetic anisotropy of Pd/Co/Pd ultrathin film. Here, we explored the magnetic anisotropy of pristine Pd/Co/Pd ultrathin film and also interface vacancy defect (Pd or Co) and the oxygen diffusion as well. No substantial change in the magnetic moment is found in the vacancy defect and also in the O diffusion structure relative to the pristine system. We found that the pristine Pd/Co/Pd system has a perpendicular magnetic anisotropy of 1.37 meV/cell. This perpendicular magnetic anisotropy decreased to 0.46 meV/cell in Pd vacancy defect and it became 0.56 meV/cell in Co vacancy defect. We also obtained similar magnetic anisotropy energy of 0.52 meV/cell in the O impurity system. Although the vacancy defect and O impurity system exhibited a similar magnetic anisotropy, we found that this feature originated from different spin-orbit coupling effect which is sensitive to the sample preparation condition.
Brahim Guezzen,Baghdad Medjahed,Abdelkader Benhelima,Abdelkrim Guendouzi,Mohamed A. Didi,Sami Zidelmal,Rafik Abdelkrim Boudia,Mehdi Adjdir 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.125 No.-
The optimal performance characteristics of hexadecyltrimethylammonium-modified bentonite (HDTMAB)for the removal of indigo carmine (IC, vat dye) from aqueous solution require a process parameterstudy. Using batch mode experiments and kinetic models, the study evaluated the adsorption behaviorand dye-adsorbent interaction at different temperatures, adsorbent dosages, and initial dye concentrations. The rating mechanism for adsorption in ICs was found to be quite similar to the pseudo-secondordermodel. All of these IC dye removal adsorption parameters were optimized using a Box-Behnkensurface statistical design with a pH of 6.6 as the starting point (as a fixed input parameter). At the 95%confidence level, the main effects of starting dye concentration and adsorbent dosage were both statisticallysignificant, as was the square impact of initial dye concentration (ANOVA). There was a negative interactionbetween the adsorbent dose and the initial dye concentration, and this led to the discovery of asubstantial detrimental effect. The primary factor in IC elimination was the initial dye concentration component(PC = 48.36%). At 34.28 C and a starting dye concentration of 53.3 mg L-1, 0.97 g L-1 of adsorbentwas optimal for removing 96.40% of IC from aqueous solutions, yielding a desirability of 1.00. The removaleffectiveness of IC dye by HDTMA-modified bentonite could be predicted and the experimental parametersoptimized using the simulated polynomial function. The regeneration capacity of the HDTMA-Badsorbent proves its importance in industrial wastewater treatment.
Analysis of edge defects in an elastic plate using SH-waves
Brahim Mohammedi,Nahil A Sobh,Diab Abueidda,Belgacem-Bouzida Aissa 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.1
The interaction of guided SH-waves with the beveled free end of a semi-infinite plate is analytically and numerically investigated. The material of the plate is assumed to be elastic, homogenous, and isotropic. The plate is modeled as a combination of a semi-infinite region and bounded wedged region separated by a common boundary. The analytical solution of the vertical free end case for the two regions is derived and used in verifying the numerical implementation. In this study, the SH 0 and the SH 1 first two incident modes are individually applied to analyze the corresponding reflected modes from the free end. Specifically, the elastic energy carried by the reflected modes is reported for a wide range of beveled angles and incident frequencies.
Exponential growth for a fractional differential equation
BRAHIM TELLAB,KAMEL HAOUAM 장전수학회 2017 Advanced Studies in Contemporary Mathematics Vol.27 No.3
This paper concerns the exponential growth of solutions for a fractional differential equation with a fractional damping of order between 0 and 1 in the presence of a source of polynomial type.
Optical Properties of a Two-Dimensional GeTe Layer
Brahim Marfoua,홍지상 한국물리학회 2020 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.76 No.3
Using the first principles calculations, we explored the optical properties of the two-dimensional -GeTe structure. The 2D monolayer -GeTe had an indirect band gap of 1.79 eV, and that indirect band gap was still observed in the bilayer although the band gap had decreased to 0.61 eV. We found that the optical band gap was much larger than the electrical band gap, which was due to the indirect band gap feature of the 2D -GeTe system. In both systems, we found a very large refractive index in the visible range. Particularly, the bilayer system had a refractive index larger than 2.5 for blue light. Furthermore, the bilayer structure was found to have a larger reflectivity at ultraviolet frequencies. Consequently, we propose that the bilayer -GeTe film can be utilized for potential optical device applications.