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Magnetoresistive properties of Ni-doped La_(0.7)Sr_(0.3)MnO_3 manganites

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Rare Metals 2016年第7期35卷 551-558页

作者： ahmed Mohamed ahmed abd el-Moez ahmed Mohamed Medhat abdelrady abdellateef Hassan ahmed abd el-Ghanny Physics Department Faculty of ScienceSohag University

Lao.7Sr0.3Mnl_xNixO3 （x = 0, 0.025, 0.050 and 0.075） ceramics were prepared by the conventional solid-state reaction method. The partial substitution of Mn by Ni2＋ leads to a decrease in cell volume as well as a structural transition from the rhombohedral to the orthorhombic structure. Ni2＋ doping increases the electrical resistivity, decreases the semiconductor-metal transition temperature （Tms） and relatively enhances the room temperature magnetoresistance （MR）, especially in x = 0.025 and around Tins. With respect to conduction mechanism, the small polaron hopping （SPH） and the variable range hopping （VRH） models were used to ex- amine conduction in the semiconducting region.

关键词： Manganites X-ray diffraction Structure electrical resistivity Magnetoresistance

Nano-crystallites Imine-based Copper(II) Complexes as Mimetics for Copper Oxidase Proteins: Synthesis,Characterization,DFT and Oxidase Mimicking Activity

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Chemical Research in Chinese Universities 2024年第6期40卷 1068-1081页

作者： ALHADHRAMI abdulrahman RAMADAN abd el-Motaleb FATHY ahmed Department of Chemistry College of ScienceTaif UniversityP.O.Box 11099Taif21944Saudi Arabia Chemistry Department Faculty of ScienceKafr El-Sheikh UniversityKafr El-SheikhEgypt Chemistry Department Faculty of ScienceZagazig UniversityZagazigEgypt

Three tridentate imine ligands containing N2S donors were synthesized via Schiff condensation between derivatives of both amino triazine and 2-carbonyl *** reaction of these ligands with CuCl2 in a molar ratio of 1:1 provides three Cu(II) complexes with the general formula [CuLn·Cl_(2)].Analytical,electrical,magnetic,and spectroscopic studies were used to assign the molecular formulae of these metallic *** function theory (DFT) calculations confirmed the structural analysis results obtained from spectroscopic *** various characterization techniques used demonstrated the penta-coordinated slightly distorted square pyramidal structure for the present Cu(II) complexes 1,2,and *** of cyclic voltammetry were done in methanol to define the electrochemical behavior of the current Cu(II) *** biomimetics of catechol oxidase (C.O.);phenoxazinone synthase (PHS) have been studied in the aerobic oxidation of some phenolic substrates,such as 3,5-di-tert-butylcatechol (3,5-DTBCH2);ortho-aminophenol (o-APH3).The three candidate oxidase mimetics showed promising activity in the order 3 > 1 > *** catalytic activity related to the structural properties of existing oxidase mimetics was *** driving force (-ΔG°) controlling the redox reactions of the present biomolecules was calculated from the redox data of Cu(II) complexes 1,2,and *** potential catalytic reaction pathway for the oxidation of the studied phenolic substrates was discussed.

关键词： Nano-crystallite Imine-based copper(II)complex Mimetics of copper oxidase protein Synthesis and characterization Density function theory(DFT)calculation

Effective damping of local low frequency oscillations in power systems integrated with bulk PV generation

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Protection and Control of Modern Power Systems 2021年第1期6卷 512-524页

作者： ahmed Hesham abd el-Kareem Mohamed abd elhameed Mahmoud M.elkholy Operation Engineer at New Capital Power Plant New Capital CityEgypt electrical Power and Machines Department Faculty of EngineeringZagazig UniversityZagazigEgypt

High penetration of renewable sources into conventional power systems results in reduction of system inertia and noticeable low-frequency oscillations (LFOs) in the rotor speed of synchronous generators. In this paper, we propose effective damping of LFOs by incorporating a supplementary damping controller with a photovoltaic (PV) generating station, where the parameters of this controller are coordinated optimally with those of a power system stabilizer (PSS). The proposed method is applied to damp local electromechanical modes by studying a system comprising a synchronous generator and a PV station connected to an infinite bus. The PV station is modeled following the instructions of the Western electricity Coordinating Council. The problem is modeled as an optimization problem, where the damping ratio of the electromechanical modes is designed as the objective function. Constraints including upper and lower limits of decision parameters and damping ratio of other modes are considered by imposing penalties on the objective function. Different optimization algorithms are used to pursue the optimal design, such as political, improved gray wolves and equilibrium optimizers. The results validate the effectiveness of the proposed controller with PSS in damping local modes of oscillations.

关键词： Low frequency oscillations Damping controller PV WECC

Permutation-substitution image encryption scheme based on a modified chaotic map in transform domain

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Journal of Central South University 2017年第9期24卷 2049-2057页

作者： Ramadan Noha ahmed Hossameldin H el-khamy Said E abd el-Samie Fathi E Faculty of electronic Engineering Menofia University Faculty of Engineering Alexandria University

A new chaotic image encryption scheme based on permutation and substitution in the Fourier domain is *** Fourier Transform(FRFT)is used before the encryption scheme to get a large degree of *** permutation is achieved by Baker map and the substitution by a key-related-to-plain-image algorithm based on the modified Logistic *** of the Logistic map is developed to increase the space of the encryption key,and hence increase the *** key of the encryption algorithm dependents on the plain image,and thus,the cipher image is sensitive to both the initial key and the plain image to resist known-plaintext and chosen plaintext *** key space is large and hence the algorithm can effectively resist brute-force *** proposed scheme is examined using different performance evaluation metrics and the results prove that the proposed scheme is highly secure,and it can effectively resist different attacks.

关键词： Backer map chaotic encryption fractional Fourier transform (FRFT) modified Logistic map

Efficacy of octreotide in the prevention of complications after pancreaticoduodenectomy in patients with soft pancreas and non-dilated pancreatic duct: A prospective randomized trial

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Hepatobiliary & Pancreatic Diseases International 2018年第1期17卷 59-63页

作者： Ayman el Nakeeb ahmed el Gawalby Mahmoud A.Ali ahmed Shehta Hosam Hamed Mohamed el Refea ahmed Moneer ahmed abd el Rafee Gastroenterology Surgical Center Mansoura University

Background: The efficacy of octreotide to prevent postoperative pancreatic fistula(POPF) of pancreaticoduodenectomy(PD) is still controversial. This study aimed to evaluate the effect of postoperative use of octreotide on the outcomes after ***: This is a prospective randomized controlled trial for postoperative use of octreotide in patients undergoing PD. Patients with soft pancreas and pancreatic duct elayed gastric emptying(P = 0.472), and early postoperative mortality(P = 0.727).Conclusions: Octreotide did not reduce postoperative morbidities, reoperation and mortality rate. Also, it did not affect the incidence of POPF and its clinically relevant variants.

关键词： Pancreaticoduodenectomy Postoperative pancreatic fistula Octreotide Periampullary tumor

Response of seed yield and fatty acid compositions for some sunflower genotypes to plant spacing and nitrogen fertilization

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Information Processing in Agriculture 2017年第3期4卷 241-252页

作者： Mohamed Ali abd el-Satar Asmaa abd-el-Halime ahmed Tamer Hassan Ali Hassan Oil Crops Research Department Field Crops Research InstituteAgricultural Research Center9 El-Gamaa St.GizaEgypt

A field experiment was conducted at the experiment Farm of Kafr-el-Hamam Research Station,Zagazig,Sharkia Governorate,Agricultural Research Center,Egypt during the two successive summer seasons of 2015 and 2016 to achieve the highest yield and good oil quality of three tested sunflower *** both seasons,the experiment was conducted using the split split plot design in randomized complete block design with three replicates arrangement keeping plant spaces(15,20 and 25 cm apart between hills)in main plots,nitrogen fertilization levels(15,30 and 45 N fad.^-1)in sub plots and sunflower genotypes(Giza 102,Sakha 53 and promising line of L120)in sub sub *** and quality traits were significantly influenced by plant spaces,nitrogen fertilization levels and genotypes as well as interactions in both seasons and their combined *** wider plant spacing of 25 cm seems to be a good compromise between the highest seed yield fad.^-1 and good acid composition of *** increasing of nitrogen fertilization level had a positive reflected on yield and desirable acid composition of *** 53 was ranked in the first order in stem diameter,head diameter,100-seed weight,seed weight plant^-1,flowered late and hence seed yield fad.^-1 as well as seed oil content whereas,Giza 102 characterized with its contained the highest proportion of oleic and linoleic unsaturated fatty *** highest values of head diameter,100-seed weight,seed weight plant^-1 and hence seed yield fad.^-1 as well as the highest proportion of oleic and linoleic unsaturated fatty acids composition were obtained by grown sunflower *** 53 at wider spacing of 25 cm with application of nitrogen fertilization levels of 45 N fad.^-*** and path analyses revealed that 100-seed weight and head diameter had the highest direct and indirect influence on seed weight plant1,at the same time also,oleic acid content and linoleic acid content had the highest direct and indirect effect inf

关键词： Sunflower Plant spacing Nitrogen fertilization Genotypes Seed yield Fatty acids

Swarming Behavior of Harris Hawks Optimizer for Arabic Opinion Mining

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Computers, Materials & Continua 2021年第12期69卷 4129-4149页

作者： Diaa Salam abd elminaam Nabil Neggaz Ibrahim abdulatief ahmed ahmed el Sawy Abouelyazed Department of Information Systems Faculty of Computers and Artificial IntelligenceBenha University12311Egypt Department of Computer Science Faculty of Computer ScienceMisr International UniversityEgypt Universite des Sciences at de la Technologie d’Oran Mohamed Boudiaf USTO-MBBP 1505EL M’naouer31000 OranLaboratoire Signal Image Parole(SIMPA)Department d’informatiqueFaculte des Mathematiques et InformatiqueAlgerie Department of Computer Science Faculty of Computers and Artificial IntelligenceBenha University12311Egypt Department of Computer Science Obour High Institute for Computers and InformaticsEgypt

At present,the immense development of social networks allows generating a significant amount of textual data,which has facilitated researchers to explore the field of opinion *** addition,the processing of textual opinions based on the term frequency-inverse document frequency method gives rise to a dimensionality *** study aims to detect the nature of opinions in the Arabic language employing a swarm intelligence(SI)-based algorithm,Harris hawks algorithm,to select the most relevant *** experimental study has been tested on two datasets:Arabic Jordanian General Tweets and Opinion Corpus for *** terms of accuracy and number of features,the results are better than those of other SI based algorithms,such as grey wolf optimizer and grasshopper optimization algorithm,and other algorithms in the literature,such as differential evolution,genetic algorithm,particle swarm optimization,basic and enhanced whale optimizer algorithm,slap swarm algorithm,and ant–lion optimizer.

关键词： Arabic opinion mining Harris hawks optimizer feature selection AJGT and OCA datasets

Dissolved gas analysis and dissipation factor measurement of mineral oil-based nanofluids under thermal and electrical faults

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High Voltage 2023年第3期8卷 455-465页

作者： ahmed Maher Diaa-eldin A.Mansour Khaled Helal Ramadan A.A.abd el Aal Department of electrical Engineering Faculty of EngineeringPort-Said UniversityPort-SaidEgypt Department of electrical Power Engineering Faculty of EngineeringEgypt-Japan University of Science and Technology(E-JUST)New Borg El-Arab CityAlexandriaEgypt Department of electrical Power and Machines Engineering Faculty of EngineeringTanta UniversityTantaEgypt

Mineral oil is the most frequent insulating liquid used in oil-immersed transformers for electrical insulation and heat ***,oil-based nanofluids are becoming more popular in scientific research as they have proved to have better dielectric and thermal *** applying these nanofluids into actual transformers,they would be exposed to thermal and electrical ***,The aim of the authors is to investigate the generation pattern of dissolved gases in nanofluids under thermal and electrical faults and to assess the applicability of traditional Dissolved Gas Analysis(DGA)techniques if oil-based nanofluids are used in ***-based nanofluid samples were prepared using a magnetic stirrer and an ultrasonic homogeniser and then subjected to simulated thermal and electrical faults in the laboratory using properly sealed test *** types of metal oxides,Silicon dioxide,Titanium dioxide,and Aluminium oxide nanoparticles,have been used to prepare nanofluids with 0.02 g/L and 0.04 g/L *** gases released and dissolved into oil due to the simulated faults were analysed and compared to traditional mineral oil as a *** dielectric dissipation factor was obtained and analysed for all *** to the findings,the presence and concentration of nanoparticles were shown to influence the amount of gases *** a result,this research is crucial in guaranteeing that traditional DGA techniques can be employed in transformers that use oil-based nanofluids.

关键词： electrical thermal dioxide

Plant phosphatidylinositol-specific phospholipase C at the center of plant innate immunity

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Journal of Integrative Plant Biology 2017年第3期59卷 164-179页

作者： ahmed M.abd-el-Haliem Matthieu H.A.J.Joosten Laboratory of Phytopathology Wageningen University Droevendaalsesteeg 1 6708 PB Wageningen The Netherlands Plant Physiology Swammerdam Institute for Life Sciences University of Amsterdam Science Park 904 1098 XH Amsterdam The Netherlands

Understanding plant resistance to pathogenic microbes requires detailed information on the molecular mechanisms controlling the execution of plant innate immune responses. A growing body of evidence places phosphoinositide-specific phospholipase C （PI-PLC） en- zymes immediately downstream of activated immune receptors, well upstream of the initiation of early defense responses. An increase of the cytoplasmic levels of free Ca2＋, lowering of the intercellular pH and the oxidative burst are a few examples of such responses and these areregulated by PI-PLCs. Consequently, PI-PLC activation represents an early primary signaling switch between elicitation and response involving the controlled hydrolysis of essential signaling phospholipids, thereby simulta- neously generating lipid and non-lipid second messenger molecules required for a swift cellular defense response. Here, we elaborate on the signals generated by PI-PLCs and their respective downstream effects, while providing an inventory of different types of evidence describing the involvement of PI-PLCs in various aspects of plant immunity. We project the discussed information into a model describing the cellular events occurring after the activation of plant immune receptors. With this review we aim to provide new insights supporting future research on plant PI-PLCs and the development of plants with improved resistance.

关键词： Pradeep Kachroo University of Kentucky USA