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Synthesis of some new fused coumarin derivatives

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Chinese Journal of Chemistry 2000年第4期18卷 590-595页

作者： EL-DEEN ibrahim Mohey ibrahim H.k. MAHMOUD F.F. Faculty of Education Suez Canal University Port-Said EgyptFaculty of Science Suez Canal University Ismailia EgyptFaculty of Science (for Girls) Al-Azhar University Nasr City Egypt

2-Hydrazino-4-hydroxy-5H-[1]-benzopyrano-[4,3-d]-pyrimidin-5-one (3) was prepared via condensation of 2 with hydrazine hydrate. Treatment of 3 with methylene chloride, ethyl chloroformate, ethyl chloroacetate and benzaldehyde yielded the corresponding 2 - ( substituted ) hydrazino - 4 -hydro-xy-5H-[1]-benzopyrano-[4,3-d]-pyrimidin-5-one (4, 5, 6, and 10), followed by cyclization of 4, 5 and 6 with dimethyl formamide and fused sodium acetate under reflux, while compound 10 was cyclized with bromine and sodium acetate in acetic acid. Compound 3 reacted with β-(toloyl) acrylic acid, ethyl α-cyano-p-methoxycinnamate, diethyl malonate and acetyl chloride affording the corresponding 2-(substituted) hydrazino-4-hydroxy-5H-[1]-benzopyrano-[4,3-d]-pyrimidin-5-one (12, 13, 14, 15 and 16).

关键词： Synthesis fused coumarin derivatives cyclization

Regression analysis of squeezing-induced hybrid nanofluid flow in Darcy-Forchheimer porous medium

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 193-208页

作者： k.MUHAMMAD M.SARFRAZ Department of Humanities and Sciences School of Electrical Engineering and Computer Science National University of Sciences and Technology Department of Mathematics Quaid-i-Azam University

This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates. One plate remains stationary, while the other moves downward at a squeezing velocity. The space between these plates contains a Darcy-Forchheimer porous medium. A mixture of water-based fluid with gold(Au) and silicon dioxide(Si O2) nanoparticles is formulated. In contrast to the conventional Fourier's heat flux equation, this study employs the Cattaneo-Christov heat flux equation. A uniform magnetic field is applied perpendicular to the flow direction, invoking magnetohydrodynamic(MHD) effects. Further, the model accounts for Joule heating, which is the heat generated when an electric current passes through the fluid. The problem is solved via NDSolve in MATHEMATICA. Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow, energy transport, and skin *** findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies. It is observed that the squeezing motion generates additional pressure gradients within the fluid, which enhances the flow rate but reduces the frictional drag. Consequently, the fluid is pushed more vigorously between the plates, increasing the flow velocity. As the fluid experiences higher flow rates due to the increased squeezing effect, it spends less time in the region between the plates. The thermal relaxation, however, abruptly changes the temperature, leading to a decrease in the temperature fluctuations.

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Ballistic resistance and energy dissipation of woven-fabric composite targets:Insights on the effects of projectile shape and obliquity angle

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Defence Technology（防务技术） 2023年第3期21卷 14-32页

作者： ibrahim Goda UniversitéBourgogne Franche-Comté FEMTO-ST InstituteDépartement Mécanique Appliquée24 Rue de L’Épitaphe25000BesançonFrance

This study aims at investigating the ballistic resistance and energy absorption in woven E-glass composite panels,considering different projectile nose shapes and oblique incidence *** that scope,three-dimensional finite element(FE)models of both projectiles and the laminated target are developed and numerical investigations are carried out using Abaqus Explicit *** composite damage model’s constitutive law encompasses nonlinear material response,material properties degradation,progressive failure,and an element deletion *** cohesive surface technique is used to represent the interface between two adjacent plies in the laminate,and the traction-separation law is used to characterize the behaviors of interlaminar degradation and *** responses attributable to fiber rupture,matrix cracking,and plasticity caused by micro-matrix cracking due to shear loading are taken into account with suitable damage evolution *** computational framework is first validated against the experimental results reported in the literature by performing ballistic impact tests on the target laminate with conical,hemispherical and blunt-ended projectile,and the numerical results showed a good comparison in terms of residual *** the framework is explored in simulating more complex failure mechanisms,with particular emphasis on the influence of the impact angle of obliquity,a parameter that is not usually analyzed in the *** that regard,the effects of normal and oblique impact on the damage morphologies and ballistic behavior of the fabric composite target in terms of energy absorption,impact contact force,and projectile residual velocity are conducted and analyzed,*** findings showed that the ballistic impact behavior of target composite is substantially influenced by projectile nose shape and incidence angle obliquity.

关键词： resistance cracking composite

Numerical investigation on the heat transfer enhancement using a confined slot impinging jet with nanofluid

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Propulsion and Power Research 2019年第4期8卷 351-361页

作者： ibrahim k.Alabdaly M.A.Ahmed Department of Mechanical Engineering College of EngineeringUniversity of AnbarRamadiAnbarIraq

In this article,laminar convective heat transfer of a confined slot impinging jet with nanofluid has been numerically investigated over Reynolds number ranges of *** circular ribs are mounted on the lower-target surface:one rib located right the stagnation point and another one located on the left of the stagnation ***2-water nanofluid with nanoparticles volume fraction ranging from 0 to 4%and nanoparticles diameters of 30 nm has been *** two-dimensional governing continuity,momentum and energy equations have been solved using finite volume method based on SIMPLE *** effect of Reynolds number,nanoparticles volume fraction,rib height and rib location on the flow and thermal characteristics are presented and *** showed that the average Nusselt number,performance factor,total entropy generation as well as friction factor increase with increasing nanoparticles volume *** addition,it is found that the best thermal-hydraulic performance factor is around 1.89 which is obtained at Reynolds number of 1000,nanoparticles volume fraction of 4%,the rib height of 0.1 and the rib location of 2.

关键词： Jet impingement Nanofluid Entropy generation Thermal-hydraulic performance Finite volume method

Effect of Aging on the Toughness of Austenitic and Duplex Stainless Steel Weldments

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Journal of Materials Science & Technology 2010年第9期26卷 810-816页

作者： Omyma Hassan ibrahim ibrahim Soliman ibrahim Tarek Ahmed Fouad khalifa Metallurgy Dept. Nuclear Research CentreAtomic Energy Authority(Egypt) Nuclear Safety Centre Atomic Energy Authority(Egypt) Shoubra Faculty of Engineering Benha University

In the present study,the effect of aging heat treatment at 650,750,and 850？C on the impact toughness of 316L austenitic stainless steel,2205 duplex stainless steel and their weldments has been *** process was conducted using the TIG（tungsten inert gas） welding *** impact testing,at room temperature,was employed to determine the effect of aging treatment on the impact properties of investigated *** treatment resulted in degradation in the impact toughness as demonstrated by the reduction in the impact fracture energy and deformation parameters（strain hardening capacity,fracture deffection,and crack initiation and propagation energy）.The degree of embrittlement was more noticeable in duplex stainless steel parent and weld-metal than in 316L stainless steel and became greater with the increase of aging *** degradation in impact toughness was discussed in relation to the observed precipitation of the intermetallic sigma phase in the microstructure of the stainless steel weldments and the corresponding fracture surface morphology.

关键词： Austenitic and duplex stainless steels Aging Instrumented impact Toughness

NEW POLY(METHACRYLATE)S CONTAINING OXIME ESTERS MOIETIES BASED ON CYCLOHEXANON AND CYCLOPENTANON

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Chinese Journal of Polymer Science 2008年第4期26卷 443-454页

作者： ibrahim Erol Afyon kocatepe Universty Faculty of Science and Arts Department of ChemistryAfyonkarahisarTurkey

The synthesis of two new methacrylates such as 2-[(cyclohexylideneamino)oxy]-2-oxoethyl methylacrylate (CHOEMA)and 2-[(cyclopentylideneamino)oxy]-2-oxoethyl methylacrylate(CPOEMA)are *** monomers produced from the reaction of corresponding cyclohexanone O-(2-chloroacetyl)oxime and cyclopentanone O-(2- chloroacetyl)oxime with sodium methacrylate was polymerized in 1,4-dioxane solution at 65℃using AIBN as an initiator. The monomers and their polymers were characterized by IR,~1H- and ^(13)C-NMR spec...

关键词： Methacrylate Oxime esters Activation energy Thermal decompositionv Biological activitiy

Wear Behaviour of Plasma Paste Boronized of AISI 8620 Steel with Borax and B_2O_3 Paste Mixtures

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Journal of Materials Science & Technology 2013年第7期29卷 662-668页

作者： ibrahim Gunes Department of Metallurgical and Materials Engineering Faculty of TechnologyAfyon Kocatepe UniversityAfyonkarahisar 03200Turkey

In the present study, AlSl 8620 steel was plasma paste boronized （PPB） by using paste mixtures with different borax and B2O3 percentages. The PPB process was carried out in a DC plasma system at 973, 1023 and 1073 k for 5 h in a gas mixture with 70% H2-30% Ar under a constant pressure of 103 Pa （10 mbar）. The thickness of boride layers ranged from 15.9 to 53.6 tim depending on the temperature and process time. The hardness of the borides formed on the surface of the steel substrate and unborided steel substrate were 1648-1924 HV0.05 and 226 HV0.05, respectively. X-ray diffraction analysis of the boride layers on the surface of the samples were obtained for FeB and Fe2B phases. The wear tests on the steel were performed by using a ball-on-disc test device at room temperature with applied load of 10 N and with a shear velocity of 0.2 m/s. Wear test results showed that the highest value of wear rate was observed in the unborided sample while the lowest wear rate was observed in the PPB samples with 30% borax ＋ 70% B4C paste at 1073 k for 5 h.

关键词： Coating Borax B2O3 Wear Coefficient of friction

Effects of P301L-TAU on post-translational modifications of microtubules in human iPSC-derived cortical neurons and TAU transgenic mice

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Neural Regeneration Research 2025年第8期20卷 2348-2360页

作者： Mohamed Aghyad Al kabbani Christoph köhler Hans Zempel Institute of Human Genetics Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany Center for Molecular Medicine Cologne(CMMC) University of CologneCologneGermany Center Anatomy Department ⅡMedical FacultyUniversity of CologneCologneGermany

TAU is a microtubule-associated protein that promotes microtubule assembly and stability in the *** is missorted and aggregated in an array of diseases known as *** are essential for neuronal function and regulated via a complex set of post-translational modifications,changes of which affect microtubule stability and dynamics,microtubule interaction with other proteins and cellular structures,and mediate recruitment of microtubule-severing *** impairment of microtubule dynamics causes neuronal dysfunction,we hypothesize cognitive impairment in human disease to be impacted by impairment of microtubule *** therefore aimed to study the effects of a disease-causing mutation of TAU(P301L)on the levels and localization of microtubule post-translational modifications indicative of microtubule stability and dynamics,to assess whether P301L-TAU causes stability-changing modifications to *** investigate TAU localization,phosphorylation,and effects on tubulin post-translational modifications,we expressed wild-type or P301L-TAU in human MAPT-kO induced pluripotent stem cell-derived neurons(i Neurons)and studied TAU in neurons in the hippocampus of mice transgenic for human P301L-TAU(p R5 mice).Human neurons expressing the longest TAU isoform(2N4R)with the P301L mutation showed increased TAU phosphorylation at the AT8,but not the p-Ser-262 epitope,and increased polyglutamylation and acetylation of microtubules compared with endogenous TAU-expressing neurons.P301L-TAU showed pronounced somatodendritic presence,but also successful axonal enrichment and a similar axodendritic distribution comparable to exogenously expressed 2N4R-wildtype-TAU.P301L-TAU-expressing hippocampal neurons in transgenic mice showed prominent missorting and tauopathy-typical AT8-phosphorylation of TAU and increased polyglutamylation,but reduced acetylation,of microtubules compared with non-transgenic *** sum,P301L-TAU results in changes in micr

关键词： human induced pluripotent stem cell microtubules P301L pR5 mice TAU tauopathy tubulin code

Recent advances on flexible electrodes for Na-ion batteries and Li–S batteries

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Journal of Energy Chemistry 2019年第5期28卷 15-44页

作者： Mohammed-ibrahim Jamesh Department of Physics and Materials Science City University of Hong Kong Applied and Plasma Physics School of Physics (A28) University of Sydney CSIR-Central Electrochemical Research Institute-Chennai Unit CSIR Madras Complex

Flexible energy storage devices are essential for emerging flexible electronics. The existing state-of-the-art Li-ion batteries are slowly reaching their limitation in terms of cost and energy density. Hence, flexible Na-ion batteries (SIBs) with abundanee Na resources and Li-S batteries with high energy density become the alternative for the Li-ion batteries in future. This review summarizes the recent advances in the development of flexible electrode materials for SIBs with metallic matrix and carb on aceous matrix such as carb on nano-tubes, carbon nano-fiber, graphene, carbon cloth, carbon fiber cloth, and cotton textiles. Then, the potential prototype flexible full SIBs are discussed. Further, the recent progress in the development of flexible electrode materials for Li-S batteries based on carb on nano-fiber, carb on nano-tubes, graphene, and cotton textiles is reviewed. Moreover, the design strategies of suitable interlayer, separator, electrolyte, and electrodes to prevent the dissolution and shuttle effect of polysulfides in flexible Li-S batteries are provided. Finally some prospective investigation trends towards future research of flexible SIBs and Li-S batteries are also proposed and discussed. The scientific and engineering knowledge gained on flexible SIBs and Li-S batteries provides conceivable development for practical application in near future.

关键词： Na-ion batteries Lithium-sulfur batteries Flexible Free-standing High performance energy storage Long cycle life