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Corrosion Behaviours of Copper Alloy in Solutions Containing Na_2SO_4 and NaCl with Different Concentrations

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journal of Materials Science & Technology 2002年第6期18卷 549-551页

作者： A.A.el-Meligi Chem. Dept. Durham Univ. Durham DH1 3LE South Road United Kingdom

Potentiodynamic polarisation, potential-time measurements, X-ray diffraction (XRD) and infrared spectroscopy (IR) have been used to investigate the effect of different concentrations of Na2SO4 in the absence and presence of NaCI, on the corrosion of Cu-alloy. The electrochemical measurements showed that the increase of Na2SO4 concentration led to increase the corrosion current density of Cu alloy and vice versa. The presence of NaCI shifted the potential to more cathodic potential, which had a great influence on the protectiveness of the Cu oxide layer formed on the surface in presence of Na2SO4. The spectrometric measurements indicated the constituents of the film formed on the alloy surface were mainly Cu2O, in addition to the oxides, NiO and Fe2O3, which were traced by XRD analysis.

关键词： Cu-alloy Polarisation X-ray diffraction Na2SO4 NaCl Oxide film

Effect of Heating Rates on the Formable Oxide Scale on a C-Steel Surface

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journal of Materials Science & Technology 2004年第5期20卷 591-594页

作者： A.A.el-Meligi electrochemistry and Corrosion Lab. Dept.of Physical ChemistryNational Research CentreDokkiCairoEgypt

Oxide scale formation on a C-steel surface has been investigated using linear heating rates ranging from 0.1℃/min to 10℃/min at high temperatures. The studies on the oxide scale formation at high temperature (650℃) at slower heating rate (0.1℃/min) shows that the kinetic regime is linear. X-ray diffraction measurements revealed that the scale constituents are significantly influenced by the heating rate. The adherence of the scale was improved by using slower heating rate (0.1℃/min-≤650℃), while above such degree the scale was susceptible to cracking and flaking out of the alloy surface. In fact, the development of oxide growth stresses can cause considerable scale cracking. As well, variation of the crystallite sizes under the aforementioned conditions might affect the scale stacking to the alloy surface. The secondary electron detector images of the oxide scale shows that the scale was imperfectly smooth and there were a number of voids and defects in the scale skin, especially at fast heating rate. This observation could be attributed to defects of the as-received alloy. In general, slower heating rate reduced the defects of the scale and improved its adherence.

关键词： C-steel Oxide scale Heating rate Weight gain XRD

Cuticular hydrocarbons in two parapatric species of ants and their hybrid

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Integrative Zoology 2011年第3期6卷 259-265页

作者： Mohamed el-SHEHABY Mohamed Sayed SALAMA elisabeth BRUNNER jürgen HEINZE Biologie I University of RegensburgRegensburgGermany Department of Entomology Ain Shams UniversityCairoEgypt

Discrimination between nestmates and non-nestmates in social insects is thought to rely on the pattern of cuticular *** investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species,Temnothorax nylanderi(Förster,1850)and Temnothorax crassispinus(Karavaiev,1926),and their *** found that although the profiles show considerable similarities,a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 *** profiles of hybrids were not consistently intermediate between those of the paternal species,suggesting either non-additive interactions among the parental biosynthetic pathways or systematic differ-ences in environment-derived odor cues.

关键词： colony odor cuticular hydrocarbons hybridization Temnothorax

Impact of time delay and cooperation strategy on the stability of a predator-prey model with Holling type III functional response

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International journal of Biomathematics 2023年第3期16卷 165-193页

作者： I.Benamara A.el Abdllaouit j.Mikramt Laboratory of Mathematics Computer Science&Applications-Security of Information Department of Mathematics Faculty of Sciences Mohammed V University in RabatMorocco

In this paper,we propose and analyze a delayed predator-prey model with Holling type III functional response taking into account cooperation behavior in *** time delay is introduced in the attack rate to represent the time necessary to trigger the *** analytical result is followed by an ecological *** investigate the effect of hunting cooperation on both the number and the level of positive steady *** observe that the level of the positive equilibrium decreases when increasing the hunting cooperation ***,we study the impact of the delay as well as the cooperation in hunting on the dynamics of the *** prove that the presence of delay in the attack rate induces stability switches around the coexisting equilibrium when predators *** addition,we consider the discrete delay as a bifurcation parameter and prove that the model undergoes a Hopf-bifurcation at the coexisting equilibrium when the delay crosses some critical *** simulations are presented to confirm our analytical findings.

关键词： Predator-prey system Holling type III discrete delay cooperative hunting Hopf-bifurcation switch of stability

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

New Conditions for Intercalation of Organic Compounds into Semiconductor Nanomaterial

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journal of Materials Science & Technology 2009年第4期25卷 470-474页

作者： A.A. el-Meligi National Research Centre Physical Chemistry Department

The intercalation of organic guests, 2-methyl pyridine （2-picoline） and 3-methyl pyridine （3-picoline） into semiconductor layered nanomaterial （MnPS3） was investigated. New conditions were applied. New phases appeared and lattice expansions were 0.36 nm for 2-picoline intercalation and 0.728 nm for 3-picoline inter- calation. The XRD （X- ray diffraction） patterns exhibit sharp hkl reflections confirming that the material is highly crystalline. The interlayer gap （0.64 nm） of the host plays a role for the arrangement of the guest in the interlayer region. The crystal structure of the MnPS3 was indexed in the monoclinic system before inter- calation. After intercalation, the crystal system was indexed in the trigonal unit cell. The lattice parameters were obtained and c-axis value was related to the （001） reflections.

关键词： Layered nanomaterials Organic guest Intercalation X-ray diffraction

Enhancing optical absorption in visible light of ZnO co-doped with europium and promethium by first-principles study through modified Becke and johnson potential scheme

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journal of Rare Earths 2019年第4期37卷 416-421页

作者： A.G.el Hachimi M.L.Ould NE A.el Yousfi A.Benyoussef A.el Kenz Laboratory of Condensed Matter and Interdisciplinary Sciences (LaMCScI) Associé Au CNRST (URAC 12) Département de Physique B.P.1014 Faculté des SciencesUniversité Mohammed V Hassan Ⅱ Academy of Science and Technology

By using first-principles calculations we studied the electronic, optical and magnetic properties of ZnO co-doped with Eu and Pm. In this calculation, we used Wien2 k code based on full potential linearized augmented plane waves(FP-LAPW) method with the modified Becke-johnson(mBj) approximation. This correction gives good band gap compared to experimental band gap. The introduction of Eu and Pm codoping leads to an increase in the band gap. electrons can transit easily from the valence band to the conduction band, which results in an enhancement of visible light absorption in a wider absorption range. Absorption spectra reach a high value in visible and infrared light regions. With the significance of the obtained results, the studied compounds may potentially find spintronic and optoelectronic applications.

关键词： Zinc oxide Rare earth Density functional theory Modified Becke-johnson Magnetic properties Spintronics

Physical Studies of Some Hydrazinobenzoic Acid Complexes

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journal of Materials Science & Technology 2005年第1期21卷 140-144页

作者： M.G.Abd el Wahed S.Abd el Wanees M.el Gamel S.Abd el Haleem Faculty of Science Zagazig University Zagazig EgyptFaculty of Science Zagazig University Zagazig EgyptFaculty of Science Zagazig University Zagazig EgyptFaculty of Science Zagazig University Zagazig Egypt

The stability constants of complexes of 2-hydrazinobenzoic acid and 4-hydrazinobenzoic acid with Ni (Ⅱ), Cu (Ⅱ), Zn (Ⅱ), Cd (Ⅱ), and Hg (Ⅱ) were determined potentiometricaIly at different temperatures. The thermodynamic parameters, △G0, △H0, and △S0 were calculated and proved that the complexation process is spontaneous and endothermic. The thermodynamic functions were analyzed in terms of electrostatic and non-electrostatic components and the results reveal that ionic bonds are formed between the studied ligands and metal ions. Conductometric titration was shown that the stoichiometry of the formed complexes are M:L and M:2L. The structure of the prepared solid complexes was characterized using IR, 1H NMR, 13C NMR spectroscopies as well as X-ray diffraction technique. Finally electrical conductivity of the ligands and their copper complexes was measured and shown that the ligands have a semiconductor behaviour.

关键词： Potentiometric titration Stability constants Thermodynamic parameters Structure of metal complexes

Wheat breeding for Hessian fly resistance at ICARDA

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The Crop journal 2022年第6期10卷 1528-1535页

作者： Wuletaw Tadesse Samira el-Hanafi Karim el-Fakhouri Imane Imseg Fatima Ezzahra Rachdad Zakaria el-Gataa Mustapha el Bouhssini International Center for Agricultural Research in the Dry Areas(ICARDA) P.O.Box 6299RabatMorocco Biodiversity and Plant Sciences Program AbroBioSciencesMohammed VI Polytechnic UniversityLot 660-Hay Moulay Rachid43150 Ben GuerirMorocco

Hessian fly(HF),Mayetiola destructor(Say)is an important pest of wheat in North Africa,North America,Southern Europe,Northern Kazakhstan,Northwestern China,and New *** can cause up to 30%yield losses and sometimes can result in complete crop failure if infestation coincides with young stage of the wheat *** to-date have shown the availability of genetic diversity in the wheat genetic resources(landraces,wild relatives,cultivars,etc.)for resistance to Hessian *** 37 resistance genes have been reported from these wheat genetic resources for resistance to Hessian fly,of which,some have been deployed singly or in combination in the breeding programs to develop high yielding varieties with resistance to *** of resistant varieties in different agro-ecologies with other integrated management measures plays key role for the control of *** paper summarizes the importance,life cycle,mechanisms of resistance,gene mining,and wheat breeding efforts for HF resistance.

关键词： Breeding Gene introgression Hessian fly Resistance