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Nuclear Science and Techniques 2019年第5期30卷 40-47页

作者： Abdesslam Lamrabet abdelmajid maghnouj Jaouad Tajmouati Mohamed Bencheikh Laboratory of Integration of Systems and Advanced Technologies Faculty of Sciences Dhar El mahrazUniversity Sidi Mohamed Ben Abdellah El Hajeb

The calculation time in the Monte Carlo simulations consistently represents an essential issue. It is often very long, and its decrease constitutes a challenge for the simulator. Generally, an MC simulation is qualified as quality or not according to two main criteria: the calculation time and the accuracy of the results. However, in most cases, the optimization of one criterion affects negatively the other. Therefore, a compromise between both of them is always required in this kind of simulation. The present work aims at studying the impact of the production threshold(or cut) of the GEANT4 toolkit on the calculation of the power deposition in the MEGAPIE spallation *** production threshold of secondaries is a GEANT4 intrinsic parameter. It indicates the limit of energy we can reach in the production of secondary particles. This study has allowed us to make the following conclusions. First,the influence of the cut on the calculation of the deposited power depends on the volume size, its arrangement and the importance of the electromagnetic processes occurring within. Second, the accuracy of the calculations can be acceptable only below a given value of the cut ***, this accuracy remains almost unchangeable from a certain value of the cut. The study has also made it possible to explore the prevalence of certain interactions in the zone of spallation in the MEGAPIE target.

关键词： Production threshold Power deposition Spallation MEGAPIE GEANT4

Assessment of the power deposition on the MEGAPIE spallation target using the GEANT4 toolkit

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Nuclear Science and Techniques 2019年第4期30卷 8-14页

作者： Abdesslam Lamrabet abdelmajid maghnouj Jaouad Tajmouati Mohamed Bencheikh Faculty of Sciences Dhar El Mahraz Laboratory of Integration of Systems and Advanced TechnologiesUniversity Sidi Mohamed Ben Abdellah El Hajeb

This work aims at evaluating the reliability of the GEANT4(GEometry ANd Tracking 4) Monte Carlo(MC) toolkit in calculating the power deposition on the Megawatt Pilot Experiment(MEGAPIE), the first liquid–metal spallation target worldwide. A new choice of codes to study and optimize this target is provided. The evaluation of the GEANT4 toolkit is carried out in comparison with the MCNPX and FLUKA MC codes. The MEGAPIE is an international project led by the Paul Scherrer Institute in Switzerland. It aims to demonstrate the safe operation of an intense neutron source to power the next generation of nuclear reactors, accelerator-driven systems(ADSs). In this study, we used the GEANT4 MC toolkit to calculate the power deposited by fast protons on the MEGAPIE *** calculation focuses on several structures and *** predictions of our calculations were compared and discussed with that of the MCNPX and FLUKA codes,adopted by the MEGAPIE project. The comparison shows that there is a very good agreement between our results and those of the reference codes.

关键词： GEANT4 Simulation MEGAPIE target Spallation Power deposition

Dynamics of Plate Equations with Memory Driven by Multiplicative Noise on Bounded Domains

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Journal of Applied Mathematics and Physics 2024年第4期12卷 1492-1521页

作者： Mohamed Y. A. Bakhet abdelmajid Ali Dafallah Jing Wang Qiaozhen Ma Fadlallah Mustafa Mosa Ahmed Eshag Mohamed Paride O. Lolika Makur Mukuac Chinor School of Mathematics University of Juba Juba South Sudan Department of Mathematics Faculty of Petroleum and Hydrology Engineering Alsalam University Almugled Sudan College of Mathematics and Statistics Northwest Normal University Lanzhou China Department of Mathematics and Physics Faculty of Education University of Kassala Kassala Sudan Department of Mathematics School of Education University of Juba Juba South Sudan

This article examines the dynamics for stochastic plate equations with linear memory in the case of bounded domain. We investigate the existence of solutions and bounded absorbing set by using the uniform pullback attractors on the tails estimates, and the asymptotic compactness of the random dynamical system is proved by decomposition method, and then we obtain the existence of a random attractor.

关键词： Plate Equations Random Attractors Memory Term Dynamical Systems

The Physiological Mechanisms Underlying N_(2)-Fixing Common Bean(Phaseolus vulgaris L.)Tolerance to Iron Deficiency

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Phyton-International Journal of Experimental Botany 2023年第7期92卷 2133-2150页

作者： abdelmajid Krouma Faculty of Sciences and Techniques University of KairouanSidi Bouzid9100Tunisia Laboratory of Ecosystems and Biodiversity in Arid Land of Tunisia Faculty of SciencesUniversity of SfaxSfaxTunisia

Iron is an essential element for plants as well as all living organisms,functioning in various physiological and biochemical processes such as photosynthesis,respiration,DNA synthesis,and N2 *** the soil,Fe bioavailability is extremely low,especially under aerobic conditions and at high pH *** contrast,plants with nodules on their roots that fix atmospheric nitrogen need much more *** highlight the physiological traits underlying the tolerance of N2-fixing common bean to iron deficiency,two genotypes were hydroponically cultivated in a greenhouse:Coco nain(CN)and Coco blanc(CB).Plants were inoculated with an efficient strain of Rhizobium tropici,CIAT899,and received a nutrient solution added with 0μM Fe(severe Fe deficiency,SFeD),5μM Fe(moderate Fe deficiency,MFeD)or 45μM Fe(control,C).Several physiological parameters related to photosynthesis and symbiotic nitrogen fixation were then *** deficiency significantly reduced whole plant and nodule growth,chlorophyll biosynthesis,photosynthesis,leghemoglobin(LgHb),nitrogenase(N2ase)activity,nitrogen,and Fe nutrition,with some genotypic *** compared to CB,CN maintained better Fe allocation to shoots and nodules,allowing it to preserve the integrity of its photosynthetic and symbiotic apparatus,thus maintaining the key functional traits of the plant metabolism(chlorophyll biosynthesis and photosynthesis in shoots,leghemoglobin accumulation,and nitrogenase activity in root nodules).Plant growth depends on photosynthesis,which needs to be supplied with sufficient iron and *** deficiency stress index(FeD-SI)and Fe use efficiency(FeUE)are two physiological traits of tolerance that discriminated the studied genotypes.

关键词： traits metabolism apparatus

A New Method for Sentiment Analysis Using Contextual Auto-Encoders

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Journal of Computer Science & Technology 2018年第6期33卷 1307-1319页

作者： Hanen Ameur Salma Jamoussi abdelmajid Ben Hamadou Multimedia Information Systems and Advanced Computing Laboratory Sfax University Sfax Technopole Sfa 3021 Tunisia

Sentiment analysis, a hot research topic, presents new challenges for understanding users＇ opinions and judg-ments expressed online. They aim to classify the subjective texts by assigning them a polarity label. In this paper, weintroduce a novel machine learning framework using auto-encoders network to predict the sentiment polarity label at theword level and the sentence level. Inspired by the dimensionality reduction and the feature extraction capabilities of theauto-encoders, we propose a new model for distributed word vector representation ＂PMI-SA＂ using as input pointwise-mutual-information ＂PMI＂ word vectors. The resulted continuous word vectors are combined to represent a sentence. Anunsupervised sentence embedding method, called Contextual Recursive Auto-Encoders ＂CoRAE＂, is also developed forlearning sentence representation. Indeed, CoRAE follows the basic idea of the recursive auto-encoders to deeply composethe vectors of words constituting the sentence, but without relying on any syntactic parse tree. The CoRAE model consistsin combining recursively each word with its context words （neighbors＇ words： previous and next） by considering the wordorder. A support vector machine classifier with fine-tuning technique is also used to show that our deep compositionalrepresentation model CoRAE improves significantly the accuracy of sentiment analysis task. Experimental results demon-strate that CoRAE remarkably outperforms several competitive baseline methods on two databases, namely, Sanders twittercorpus and Facebook comments corpus. The CoRAE model achieves an efficiency of 83.28% with the Facebook dataset and97.57% with the Sanders dataset.

关键词： sentiment analysis recursive auto-encoder stacked auto-encoder pointwise mutual information deep embed-ding representation

Functional Analysis of the Genotypic Differences in Response of Pea (Pisum sativum L.) to Calcareous-Induced Iron Deficiency

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Phyton-International Journal of Experimental Botany 2023年第2期92卷 521-536页

作者： Sameh Barhoumi Hasna Ellouzi abdelmajid Krouma Laboratory of Ecosystems and Biodiversity in Arid Land of Tunisia Faculty of SciencesUniversity of SfaxSfax3000Tunisia Centre of Biotechnology of Borj Cedria Hammam Lif2050Tunisia Faculty of Sciences and Techniques University of KairouanKairouan9100Tunisia

Lime-induced iron chlorosis is a major nutritional disorder causing severe plant growth and yield reduction in the calcareous soils of *** understanding the behavior of key metabolic functions of peas on calcareous soils,the identification of useful traits of tolerance,and the exploration of the genotypic differences in response to this constraint remain the most efficient approaches due to their coast,environmental benefits,and *** this purpose,a greenhouse experiment was conducted on three pea genotypes(Alexandra:Alex,Douce de provence:DP,and Merveille de Kelvedon:MK)cultivated on calcareous soil(Fe-deficient)and fertile soil(control).Plant growth,SPAD index,iron nutrition and distribution,photosynthesis,and antioxidant enzymes were deeply analyzed to discriminate genotypic ***-induced iron deficiency reduced SPAD index,plant growth,net photosynthesis,and tissue Fe content against a significant stimulation of the oxidative stress indicators,H2O2 and Malondialdehyde(MDA).Moreover,we reported a significant induction of SOD and CAT activity in shoots and roots of the Alexandra *** use efficiency increased on calcareous soil and clearly discriminated the studied *** genotype was found to be the most tolerant to lime-induced iron *** genotype protects its tissues against oxidative stress by stimulating enzyme activities(SOD and CAT)and develops significant efficiency of Fe uptake,translocation to shoots and use when cultivated on calcareous soil.

关键词： Calcareous-induced Fe deficiency catalase Fe use efficiency photosynthesis superoxide dismutase

Fluid Flow and Convective Heat Transfer in a Water Chemical Condenser

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Fluid Dynamics & Materials Processing 2020年第2期16卷 199-209页

作者： Mounir Kriraa Khalid Souhar Driss Achemlal Youssef Ait Yassine abdelmajid Farchi IMII Ingénierie Management et Innovation IndustriellFSTHassan 1er UniversitySettatMorocco LMPEQ National School of Applied SciencesSafiCadi Ayyad UniversityMarrakechMorocco LGEMS Laboratory National School of Applied SciencesIbn Zohr UniversityAgadir80000Morocco Engineering Sciences Laboratory Department of MathematicsPhysics and InformaticsPolydisciplinary Faculty of TazaSidi Mohamed Ben Abdellah UniversityFezMorocco Ibn Zohr University Higher School of TechnologyLaâyouneMorocco Ibn Zohr University Faculty of ScienceLaboratory of Thermodynamics and EnergyAgadirMorocco

In this paper,a detailed investigation of water(Pr=7.0)convection in a chemical condenser is carried *** openings are located along one side of the *** Navier-Stokes equations are solved in the frame of a control volume method using the SIMPLEC algorithm to implement adequate coupling of pressure and *** emphasis is given to the influence of the Reynolds number,the tilt of the channel and the Rayleigh number on the convective heat *** are presented and discussed allowing the control parameters to span relatively wide intervals:Rayleigh number(10^(4)≤Ra≤5×10^(5)),channel inclination(0°≤90°)and Reynolds number(10≤Re≤1000).On the basis of these results,a new correlation of the Nusselt number is elaborated.

关键词： Chemical condenser tilted channel convection numerical study heat transfer

Differential Effect of Artemisinin Against Cancer Cell Lines

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Natural Products and Bioprospecting 2014年第3期4卷 189-196页

作者： Mounir Tilaoui Hassan Ait Mouse Abdeslam Jaafari abdelmajid Zyad Laboratory of Biological Engineering Natural SubstancesCellular and Molecular Immuno-pharmacologyImmunobiology of Cancer Cells ClusterFaculty of Science and TechnologyP.Box 52323000 Be´ni-MellalMorocco

The present study aims at defining the differential cytotoxicity effect of artemisinin toward P815(murin mastocytoma)and BSR(kidney adenocarcinoma of hamster)cell *** was measured by the growth inhibition using MTT *** in vitro cytotoxicity studies were complemented by the determination of apoptotic DNA fragmentation and Annexin V-streptavidin-FITC ***,we examined the in vitro synergism between artemisinin and the chemotherapeutic drug,*** in vivo study was investigated using the DBA2/P815(H2d)mouse *** artemisinin acted on both tumor cell lines,P815 was much more sensitive to this drug than BSR cells,as revealed by the respective IC50 values(12 lM for P815 and 52 lM for BSR cells).On another hand,and interestingly,apoptosis was induced in P815 but not induced in *** data,reveal an interesting differential cytotoxic effect,suggesting the existence of different molecular interactions between artemisinin and the studied cell *** vivo,our results clearly showed that the oral administration of artemisinin inhibited solid tumor *** study demonstrates that artemisinin caused differential cytotoxic effects depending not only on the concentration and time of exposure but also on the target cells.

关键词： Artemisinin Cytotoxicity Apoptosis/necrosis Synergism Antitumor activity

Reduction Band Gap Energy of TiO<sub>2</sub>Assembled with Graphene Oxide Nanosheets

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Graphene 2018年第4期7卷 31-38页

作者： abdelmajid Timoumi Physics Department Faculty of Applied Science Umm AL-Qura University Makkah KSA Photovoltaic and Materials Semiconductors Laboratory National Engineering School of Tunis Tunis Tunisia

This research work aims to reduce the band gap of thin layers of titanium oxide by the incorporation of graphene oxide sheets. Thin layers of the TiO2-GO composites were prepared on a glass substrate by the spin-coating technique from GO and an aqueous solution of TiO2. A significant decrease in optical band gap was observed at the TiO2-GO compound compared to that of pure TiO2. Samples as prepared were characterized using XRD, SEM and UV-visible spectra. XRD analysis revealed the amorphous nature of the deposited layers. Scanning electron microscope reveals the dispersion of graphene nanofiles among titanium oxide nanoparticles distributed at the surface with an almost uniform size distribution. The band gap has been calculated and is around 2 eV after incorporation of Graphene oxide. The chemical bond C-Ti between the titanium oxide and graphene sheets is at the origin of this reduction.

关键词： Titanium (IV) Oxide Graphene Oxide TiO2-GO Thin Films Composite Materials

Robust Estimators for Poisson Regression

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Open Journal of Statistics 2023年第1期13卷 112-118页

作者： Idriss abdelmajid Idriss Weihu Cheng College of Applied Science Department of Statistics Beijing University of Technology Beijing China

The present paper proposes a new robust estimator for Poisson regression models. We used the weighted maximum likelihood estimators which are regarded as Mallows-type estimators. We perform a Monte Carlo simulation study to assess the performance of a suggested estimator compared to the maximum likelihood estimator and some robust methods. The result shows that, in general, all robust methods in this paper perform better than the classical maximum likelihood estimators when the model contains outliers. The proposed estimators showed the best performance compared to other robust estimators.

关键词： Poisson Regression Model Maximum Likelihood Estimator Robust Estimation Contaminated Model Weighted Maximum Likelihood Estimator