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Rare earth oxides doped NiO/γ-Al_2O_3 catalyst for oxidative dehydrogenation of cyclohexane

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Journal of Rare Earths 2015年第6期33卷 611-618页

作者： Hany M.AbdelD ayem M.Faiz Hesham S.Abdel-Samad salah a.hassan Center of Research Excellence in Petroleum Refining & Petrochemicals (CoR E-PRP) King Fahd University of Petroleum & Minerals Chemistry Department College of Science King Faisal University Chemistry Department Faculty of Science Ain Shams University Surface Science Laboratory Physics Department King Fahd University of Petroleum &Minerals Department of Basic Sciences and Technology Community College Taibah University

The effect of rare earth oxides （RE=Ce, La, Gd, and Dy） doping of alumina support in NiO/7-A1203 system was investi- gated on its catalytic performance in oxidative dehydrogenation （ODH） of cyclohexane. The physicochemical properties of various samples were followed up through N2 physisorption, temperature programmed reduction （H2-TPR）, X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and potentiometric acid-base titration techniques. In the parent NiO/y-A1203 catalyst, Ni species were found to be strongly interacted with alumina surface. Addition of rare earth dopants to ）＇-A1203 in the catalyst system affected the nickel-alumina interaction and resulted in significant modifications in the catalytic performances in the ODH reaction. The results re- vealed the beneficial role of both La203 and Gd2Os doping in enhancing the ODH catalytic activity and selectivity to cyclohexene. H2-TPR and XPS results indicated that majority of Ni species in NiO/La203 modified T-A1203 were more weakly interacted with La203 and alumina whereas both NiO like species and nickel aluminate were present on the surface. Doping with cerium or dyspro- sium increased the nickel-support interaction and led to a decrease in surface nickel concentration. In case of doping with Ce, surface concentration of cerium oxide was higher than those of the other RE oxides; the doped catalyst reached its steady state activity faster than the other catalysts. The acid-base results suggested that RE metals were interacted most likely with acidic surface hydroxyl groups. The degree of nickel-alumina interaction decreased in the following order： LaAI〉GdAI〉CeAI〉DyA1.

关键词： nickel oxide rare-earth oxides doping Ni-A1203 interaction surface acidity oxidative dehydrogenation cyclohexane rare earths

Fermion Mass Hierarchies in Singlet-Extended Minimal-Supersymmetric-Standard-Model Quivers

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Chinese Physics Letters 2011年第11期28卷 64-67页

作者： salah Eddine Ennadifi Adil Belhaj El hassan Saidi Laboratory of High Energy Physics Modeling and SimulationFaculty of ScienceMohammed V-Agdal UniversityRabatMorocco Centre of Physics and Mathematics CPM-CNESTENRabatMorocco

In the context of type-IIA orientifold compactifications,we discuss the fermion masses in a two-singlet-extended minimal-supersymmetric-standard-model four-stack quiver with U(3)×Sp(1)×U(1)×U(1)gauge *** corresponding effective superpotential exhibits hierarchical coupling term scales giving a partial solution to the fermion masses *** the known data with upper bound neutrino masses mvt≤2 eV,we estimate the relevant scales for the model.

关键词： symmetry problem symmetric

The Spectrum of a Rational Function

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Algebra Colloquium 2020年第3期27卷 477-482页

作者： salah Najib Laboratoire ATRES Faculte Polydisciplinaire de Khouribga Universite Sultan Moulay Slimane BP.145Hay EzzaytouneKhouribgaMorocco

Let k be an infinite field,A be a finite set of k,and Q∈k[x](with x=(x_(1),...,X_(n))and n≥2)be a noncons taut *** main goal of this paper is to construct a polynomial P(x)∈k[x]with suitably large partial degrees i... 详细信息

关键词： irreducible and indecomposable polynomial spectrum of rational function field with product formula Hilbert subset

On Two Natural Extensions of n-normality

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Acta Mathematica Sinica,English Series 2023年第6期39卷 1147-1152页

作者： salah MECHERI Faculty of Mathematics and informatics Mohamed El Bachir El Ibrahimi UniversityBordj Bou ArreridjAlgeria

A bounded linear operator T on a complex Hilbert space H is called n-normal if T^(*)T^(n)=T^(n)T^(*).By Fuglede’s theorem T is n-normal if and only if T^(n)is *** k,n∈*** a bounded linear operator T is said to be of typeⅠk-quasi-n-normal if T^(*k){T^(*)T^(n)-T^(n)T^(*)}T^(k)=0,and T is said to be of typeⅡk-quasi-n-normal if T^(*k){T^(*n)T^(n)-T^(n)T^(*n)}T^(k)=0.1-quasi-n-normal is called *** shall show that(1)typeⅠquasi-2-normal and typeⅡquasi-2-normal are different classes;(2)the intersection of the class of typeⅠquasi-2-normal and the class of typeⅡquasi-2-normal is equal to the class of *** also give some examples of type I k-quasi-n-normal and typeⅡ*** also show that Weyl’s theorem holds for this class of operators and every k-quasi-n-normal operator has a non trivial invariant subspace.

关键词： Normal operator n-normal operator invariant subspace

Risk factors and prognosis of pediatric rhegmatogenous retinal detachment in Egypt:a university hospital based study

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International Journal of Ophthalmology(English edition) 2023年第12期16卷 2034-2040页

作者： Mohamed Gaber Eissa Mohamad Amr salah Eddin Abdelhakim Tamer Ahmed Macky hassan Aly Mortada Department of Ophthalmology Kasr Al Ainy HospitalFaculty of MedicineCairo UniversityCairo 11431Egypt

AIM:To study and compare the predisposing factors and clinical features of pediatric,adult,and elderly rhegmatogenous retinal detachment(RRD).METHODS:This is an observational analytic crosssectional study in which patients with RRD admitted for surgery during 6mo period were divided into 3 age groups:pediatric(60y).Patients’demographic data,clinical features,RRD predisposing factors/features including myopia(axial length≥26.5 mm),aphakia/pseudophakia,blunt trauma,peripheral retinal degenerations,history of RRD in the fellow eye,and surgical interventions/findings were recorded and ***:Totally 142 patients(142 eyes)were studied:26(18.31%)pediatrics,86(60.56%)adults,and 30(21.13%)*** patients had a significantly higher intraocular pressures and cataracts compared to the other 2 groups(P=0.04).The RRD extent was larger in pediatric group(mostly 4 quadrants)compared to adults and elderly(mostly 2 quadrants),but it was not statistically insignificant(P=0.242).There were not statistically significantly differences in proliferative vitreoretinopathy(PVR)rate,posterior vitreous detachment(PVD)rate,number,site,shape,and size of breaks in three *** three groups had macular detachment in all *** and peripheral retinal degenerations were found to be more significant in adults(P=0.049,P=0.035,respectively),while blunt trauma was higher but insignificant in pediatric eyes(P=0.052).Pars plana vitrectomy(PPV)with silicone oil as a tamponade was the most used surgery in all ***:There are no significant difference in PVR rate in pediatric eyes but a significant higher rate of total *** trauma is more frequent in pediatrics eyes while myopia and/or peripheral retinal degenerations are more frequent in older *** rate of PPV as a choice for surgery is similar among all age groups.

关键词： rhegmatogenous retinal detachment pediatric predisposing factors proliferative vitreoretinopathy peripheral retinal degenerations

RIESZ IDEMPOTENT AND BROWDER'S THEOREM FOR ABSOLUTE-(p,r)-PARANORMAL OPERATORS

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Acta Mathematica Scientia 2012年第6期32卷 2259-2264页

作者： salah Mecheri Department of Mathematics College of ScienceTaibah UniversityP.O.Box 30002Al Madinah Al MunawarahSaudi Arabia

An operator T is said to be paranormal if ｜｜T^2 x ｜｜〉｜｜Tx｜｜^2 holds for every unit vector x. Several extensions of paranormal operators are considered until now, for example absolute-k-paranormal and p-paranormal introduced in [10], [14], respectively. Yamazaki and Yanagida [38] introduced the class of absolute-（p, r）-paranormal operators as a further generalization of the classes of both absolute-k-paranormal and p-paranormal operators. An operator T ∈ B（H） is called absolute-（p, r）-paranormal operator if ｜｜｜T｜p｜T^＊｜^rx｜｜^r 〉｜｜｜T^＊｜^rx｜｜p＋r for every unit vector x ∈ H and for positive real numbers p 〉 0 and r 〉 0. The famous result of Browder, that self adjoint operators satisfy Browder＇s theorem, is extended to several classes of operators. In this paper we show that for any absolute-（p, r）- paranormal operator T, T satisfies Browder＇s theorem and a-Browder＇s theorem. It is also shown that if E is the Riesz idempotent for a nonzero isolated point μ of the spectrum of a absolute-（p, r）-paranormal operator T, then E is self-adjoint if and only if the null space of T -μ, N（T - μ） N（T^＊ - ^μ）.

关键词： absolute-(p, r)-paranormal operator Browder's theorem Weyl's spectrum

Optimised CNN Architectures for Handwritten Arabic Character Recognition

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Computers, Materials & Continua 2024年第6期79卷 4905-4924页

作者： salah Alghyaline Department of Computer Science TheWorld Islamic Sciences and Education UniversityAmman1101-11947Jordan

Handwritten character recognition is considered challenging compared with machine-printed characters due to the different human writing *** is morphologically rich,and its characters have a high *** Arabic language includes 28 *** character has up to four shapes according to its location in the word(at the beginning,middle,end,and isolated).This paper proposed 12 CNN architectures for recognizing handwritten Arabic *** proposed architectures were derived from the popular CNN architectures,such as VGG,ResNet,and Inception,to make them applicable to recognizing character-size *** experimental results on three well-known datasets showed that the proposed architectures significantly enhanced the recognition rate compared to the baseline *** experiments showed that data augmentation improved the models’accuracies on all tested *** proposed model outperformed most of the existing *** best achieved results were 93.05%,98.30%,and 96.88%on the HIJJA,AHCD,and AIA9K datasets.

关键词： Optical character recognition(OCR) handwritten arabic characters deep learning

Arabic Optical Character Recognition:A Review

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Computer Modeling in Engineering & Sciences 2023年第6期135卷 1825-1861页

作者： salah Alghyaline Computer Science Department TheWorld Islamic Sciences and Education UniversityAmman1101-11947Jordan

This study aims to review the latest contributions in Arabic Optical Character Recognition(OCR)during the last decade,which helps interested researchers know the existing techniques and extend or adapt them *** study describes the characteristics of the Arabic language,different types of OCR systems,different stages of the Arabic OCR system,the researcher’s contributions in each step,and the evaluationmetrics for *** study reviews the existing datasets for the Arabic OCR and their ***,this study implemented some preprocessing and segmentation stages of Arabic *** study compares the performance of the existing methods in terms of recognition *** addition to researchers’OCRmethods,commercial and open-source systems are used in the *** Arabic language is morphologically rich and written cursive with dots and diacritics above and under the *** of the existing approaches in the literature were evaluated on isolated characters or isolated words under a controlled environment,and few approaches were tested on pagelevel *** comparative studies show that the accuracy of the existing Arabic OCR commercial systems is low,under 75%for printed text,and further improvement is ***,most of the current approaches are offline OCR systems,and there is no remarkable contribution to online OCR systems.

关键词： Arabic Optical Character Recognition(OCR) Arabic OCR software Arabic OCR datasets Arabic OCR evaluation

Evolution of microstructural and mechanical properties of AISI 316 during continuous drive friction welding process

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China Welding 2020年第4期29卷 7-12页

作者： Ammar Jabbar hassan Taoufik Boukharouba Djamel Miroud Nacer-Eddine Titouche salah Ramtani Houari Boumediene University of Sciences and Technology BP.32El-Alia16111 Bab-EzzoaurAlgiersAlgeria Birine Nuclear Research Center BP.180Ain OusseraDjelfa17200Algeria Paris University 13 Galilée Institute93430 VilletaneuseFrance

The aim of present study is introducing a method by subdividing friction welding phases into three steps according to the temperature change during continuous drive friction welding operation. Thermal curve allowable subdividing of the friction welding phase's time into three distinct periods, while the microstructure evolution during friction welding goes through three different situations. The effects of three distinct periods were achieved by macro-microscopy, microhardness HV_(0.1), tensile tests and scanning electronic microscopy(SEM).The results clearly show that the microstructure during the friction phase goes through three completely different situations which mechanically influenced on microstructure, tensile strength and ductility of the welded joint.

关键词： Continuous drive friction welding friction welding phase steps tensile strength microhardness microstructure