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Structural,morphological and photoluminescence characterizations of Sm^(3+) doped Y_(2)O_(3) nano-sized phosphors synthesized by ultrasound assisted sol-gel method

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Journal of Rare Earths 2023年第1期41卷 51-59页

作者： Lyes Lamiri Badis Kahouadji mourad Berd Abdelmoumen Abdellatif Lotfi Benchallal Lakhdar Guerbous Salim Ouhenia Abdelhafid Souici Leila Amiour Abdelhalim Zoukel Madani Samah Department of TCSN University of BejaiaBejaia06000Algeria Department of Technology University of BejaiaBejaia06000Algeria Department of Technology Laboratory of LECVEUniversity of BejaiaBejaiaO6000Algeria Department of Physics of Materials University of Science and Technology Houari BoumedieneAlgiersAlgeria Laser Department/Nuclear Research Center of Algiers(CRNA) 02Boulevard Frantz FanonB.P.399Algiers16000Algeria Laboratory of Physical-chemistry University of BejaiaBejaia06000Algeria Phase Transformation Laboratory Universite Freres Mentouri Constantine 1Algeria Laboratory Physico-Chemistry of Materials Laghouat UniversityTechnical Platform of Physico-Chemical Analysis(PTAPC-Laghouat-CRAPC)LaghouatAlgeria

Nanosized 1 at% Sm^(3+)doped Y_(2)O_(3)powders were prepared by an ultrasound assisted sol-gel method.Y_(2)O_(3):Sm^(3+)powders crystallize in Y_(2)O_(3)pure cubic phase and XRD analysis shows that the as-used agitation protocol affects strongly the crystallite’s shape and mean *** recorded emission spectra under λ_(em)=600 nm exhibit two absorption bands;the first one is assigned to O^(2-)→Sm^(3+)charge transfer state(CTS) with a maximum absorption at 223 nm,and the second is due to intraconfigurational transition 4f^(5)-4f^(5) of Sm^(3+) with a maximum absorption at 407 *** 223 and 407 nm transitions are attributed to characteristics intra-configurational transitions of Sm^(3+).All emission spectra are dominated by reddish/orange luminescence located at 606 nm and assigned to ^(4)G_(5/2)→^(6)H_(7/2) *** is found that the photoluminescence intensity of samples obtained under excitation at 407 nm is 60 times smaller than that obtained under 223 nm *** time measurements of the ^(4)G_(5/2)→^(6)H_(7/2) luminescence transition indicate that decay time of nano-sized powder is significantly shorter than bulk material one.

关键词： Y_(2)O_(3):Sm^(3+)nano-sized powder Sol-gel method Ultrasound Charge transfer Photoluminescence Rare earths

High-performance LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2) cathode by nanoscale lithium sulfide coating via atomic layer deposition

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Journal of Energy Chemistry 2022年第6期31卷 531-540,I0015页

作者： Xin Wang Jiyu Cai Yang Ren mourad Benamara Xinwei Zhou Yan Li Zonghai Chen Hua Zhou Xianghui Xiao Yuzi Liu Xiangbo Meng Department of Mechanical Engineering University of ArkansasFayettevilleAR 72701USA Chemical Sciences and Engineering Division Argonne National LaboratoryLemontIL 60439USA The Advanced Photon Source Argonne National LaboratoryLemontIL 60439USA Institute for Nanoscience and Engineering University of ArkansasFayettevilleAR 72701USA Center for Nanoscale Materials Argonne National LaboratoryLemontIL 60439USA Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China University of Chinese Academy Sciences Beijing 100049China National Synchrotron Light Source II Brookhaven National LaboratoryUptonNY 11973USA

The commercialization of nickel-rich LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NMC811) has been hindered by its continuous loss of practical capacity and reduction in average working *** address these issues,surface modification has been well-recognized as an effective *** from the coatings reported in literature to date,in this work,we for the first time report a sulfide coating,amorphous Li_(2)S via atomic layer deposition (ALD).Our study revealed that the conformal nano-Li_(2)S coating shows exceptional protection over the NMC811 cathodes,accounting for the dramatically boosted capacity retention from~11.6%to~71%and the evidently mitigated voltage reduction from 0.39 to 0.18 V after 500 charge–discharge *** addition,the Li_(2)S coating remarkably improved the rate capability of the NMC811 *** investigation further revealed that all these beneficial effects of the ALD-deposited nano-Li_(2)S coating lie in the following aspects:(i) maintain the mechanical integrity of the NMC811 electrode:(ii) stabilize the NMC electrode/electrolyte interface:and (iii) suppress the irreversible phase transition of NMC ***,this study also has revealed that the nano-Li_(2)S coating has played some unique role not associated with traditional non-sulfide coatings such as *** this regard,we disclosed that the Li_(2)S layer has reacted with the released O_(2) from the NMC lattices,and thereby has dramatically mitigated electrolyte oxidation and electrode ***,this study is significant and has demonstrated that sulfides may be an important class of coating materials to tackle the issues of NMCs and other layered cathodes in lithium batteries.

关键词： Nickel-rich cathodes Atomic layer deposition Lithium sulfide Microcracking Phase transition Interfacial reactions

Hybrid immunizing solution for job recommender system

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Frontiers of Computer Science 2017年第3期11卷 511-527页

作者： Shaha AL-OTAIBI mourad YKHLEF Department of Information Systems College of Computer and Information Sciences Princess Nourah Bint Abdulrahman University Riyadh 11671 Saudi Arabia Department of Information Systems College of Computer and Information Sciences King Saud University Riyadh 11543 Saudi Arabia

Two traditional recommendation techniques, content-based and collaborative filtering （CF）, have been widely used in a broad range of domain areas. Both meth- ods have their advantages and disadvantages, and some of the defects can be resolved by integrating both techniques in a hybrid model to improve the quality of the recommendation. In this article, we will present a problem-oriented approach to design a hybrid immunizing solution for job recommen- dation problem from applicant＇s perspective. The proposed approach aims to recommend the best chances of opening jobs to the applicant who searches for job. It combines the artificial immune system （AIS）, which has a powerful explo- ration capability in polynomial time, with the collaborative filtering, which can exploit the neighbors＇ interests. We will discuss the design issues, as well as the hybridization process that should be applied to the problem. Finally, experimental studies are conducted and the results show the importance of our approach for solving the job recommendation problem.

关键词： content-based collaborative filtering (CF) hy- bridization computational intelligence (CI) artificial im- mune system (AIS) clonal selection correlation-based simi- larity

Effect of Water Concentration on the Characterization of Sprayed Cd_(0.5)Zn_(0.5)S Films

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Chinese Physics Letters 2011年第6期28卷 237-240页

作者： Sur S Öztürk Z Öztaş.M bedir M Özdemir Y Department of Engineering Physics University of GaziantepGaziantepTurkey Chemical and Process Engineering Department Yalova UniversityYalovaTurkey

Cd_(0.5)Zn_(0.5)S film samples are prepared by a spray pyrolysis technique using aqueous solutions of CdC_(l2),ZnC_(l2),SC(NH2)2 and deionized water,which are atomized using compressed air as the carrier gas onto glass substrates with different water(H2O)concentrations.H2O is used as the *** prepared films are characterized by means of XRD and UV−VIS *** results reveal that the structures and properties of the films are greatly affected by the H2O *** in a certain range of concentrations promotes the formation of the Cd_(0.5)Zn_(0.5)S films and improves the properties of the films.

关键词： spectroscopy pyrolysis

Analytical fits to the synchrotron functions

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Research in Astronomy and Astrophysics 2013年第6期13卷 680-686页

作者： mourad Fouka Saad Ouichaoui Research Center in Astronomy Astrophysics and GeophysicsB. P. 63 Algiers ObservatoryBouzaréah Algiers Algeria Université des Sciences et de la Technologie Houari Boumediène (USTHB) Faculté dePhysique Laboratoire SNIRMB.P. 32 El-Alia 16111 Bab Ezzouar Algiers Algeria

Accurate fitting formulae to the synchrotron function, F（x）, and its com- plementary function, G（x）, are performed and presented. The corresponding relative errors are less than 0.26% and 0.035% for F（x） and G（x）, respectively. To this end we have, first, fitted the modified Bessel functions, Ks/3（x） and K2/3（x）. For all the fitted functions, the general fit expression is the same, and is based on the well known asymptotic forms for low and large values of z for each function. It consists of multi- plying each asymptotic form by a function that tends to unity or zero for low and large values of z. Simple formulae are suggested in this paper, depending on adjustable parameters. The latter have been determined by adopting the Levenberg-Marquardt algorithm. The proposed formulae should be of great utility and simplicity for com- puting spectral powers and the degree of polarization for synchrotron radiation, both for laboratory and astrophysical applications.

关键词： radiation processes: non thermal -- methods: analytical

Parametric Estimation of Interconnected Nonlinear Systems Described by Input-output Mathematical Models

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International Journal of Automation and computing 2016年第4期13卷 364-381页

作者： mourad Elloumi Samira Kamoun Laboratory of Sciences and Techniques of Automatic Control & Computer Engineering National Engineering School of Sfax (ENIS) University of Sfax Tunisia B.P. 1173 3038 Sfax Tunisia

In this paper, two types of mathematical models are developed to describe the dynamics of large-scale nonlinear systems, which are composed of several interconnected nonlinear subsystems. Each subsystem can be described by an input-output nonlinear discrete-time mathematical model, with unknown, but constant or slowly time-varying parameters. Then, two recursive estimation methods are used to solve the parametric estimation problem for the considered class of the interconnected nonlinear systems. These methods are based on the recursive least squares techniques and the prediction error method. Convergence analysis is provided using the hyper-stability and positivity method and the differential equation approach. A numerical simulation example of the parametric estimation of a stochastic interconnected nonlinear hydraulic system is treated.

关键词： Large-scale nonlinear systems interconnected nonlinear systems deterministic systems stochastic systems input-outputmathematical models parametric estimation algorithm convergence analysis.

Additive Preservers of Drazin Invertible Operators with Bounded Index

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Acta Mathematica Sinica,English Series 2017年第9期33卷 1225-1241页

作者： mourad OUDGHIRI Khalid SOUILAH Departement Math-Info Labo LAGAFaculte des SciencesUniversite Mohammed Premier60000 OujdaMaroc

Let B（X） be the algebra of all bounded linear operators on an infinite-dimensional complex or real Banach space X. Given an integer n 〉 1, we show that an additive surjective map Ф on B（X） preserves Drazin invertible operators of index non-greater than n in both directions if and only if Ф is either of the form Ф（T） = aATA-1 or of the form Ф（T） = aBT＊B-1 where a is a non-zero scalar, A ： X → X and B ： X＊ → X are two bounded invertible linear or conjugate linear operators.

关键词： Linear preserver problems Drazin inverse ascent descent

A comprehensive simulator for assessing the reliability of a photovoltaic panel peak power tracking system

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Frontiers in Energy 2015年第2期9卷 170-179页

作者： Nabil KAHOUL mourad HOUABES Ammar NECAIBIA Laboratoire d' Electrotechnique d' Annaba Badji Mokhtar-AnnabaUniversity Annaba 23000 Algeria Research Unit of Renewable Energy in Saharan Middle (URER/MS) Adrar 01000 Algeria

When designing a maximum power point tracking （MPPT） algorithm, it is often difficult to correctly predict, before field testing, the behavior of this MPPT under varying solar irradiation on photovoltaic （PV） panels. A solution to this problem is to design a maximum power point trackers simulator of a PV system used to test MPPT algorithms. This simulator must have the same role as the MPPT card of the PV panel and thus will fully emulate the response of a real MPPT card of the PV panel. Therefore, it is a good substitute to help to test the peak power trackers of the PV system in the laboratory. This paper describes a simple peak power trackers simulator of the PV system which has a short response time thus, can be used to test MPPT algorithms under very rapid variation condition. The obtained results and the theoretical operation confirm the reliability and the superior perfor- mance of the proposed model.

关键词： photovoltaicdesign maximum powermicroprocessormodule DC-DC converter,point tracking (MPPT) card,

Characterization of Undoped and Cu-Doped ZnO Thin Films Deposited on Glass Substrates by Spray Pyrolysis

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Chinese Physics Letters 2006年第4期23卷 939-942页

作者： Metin bedir Mustafa Oztas A. Necmeddin Yazici E. Vural Kafadar Department of Engineering Physics University of Gaziantep Gaziantep 27310 Turkey

Undoped and copper doped zinc oxide （ZnO） thin films have been prepared on glass substrates by spray pyrolysis technique. The films were doped with copper using the direct method by addition of a copper salt （CuCl2） in the spray solution of ZnO. Variation of structural, electrical, optical and thermoluminescence （TL） properties with doping concentrations is investigated in detail.

关键词： CHEMICAL-VAPOR-DEPOSITION ZINC-OXIDE FILMS OPTICAL-PROPERTIES TRANSPARENT