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Thermal properties and high-temperature ablation of high-entropy (Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))b_(2) coating on graphite substrate

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Journal of Advanced ceramics 2024年第8期13卷 1268-1281页

作者： Ana c.Feltrin Daniel Hedman farid Akhtar Division of Materials science Lulea University of TechnologyLulea 97187Sweden center for Multidimensional carbon Materials(cMcM) Institute for Basic Science(IBS)Ulsan 44919Republic of Korea

An entropy-stabilized multicomponent ultrahigh-temperature ceramic(UHTc)coating,(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))b_(2),on a graphite substrate was in-situ sintered by spark plasma sintering(sPs)from constituent transition metal diboride ***(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))b_(2) coating had a hardness of 31.2±2.1 GPa and resisted 36.9 GPa of stress before delamination,as observed at the *** temperature-dependent thermal properties of the multicomponent diboride(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))b_(2) were obtained by molecular dynamics(MD)simulations driven by a machine learning force field(MLFF)trained on density functional theory(DFT)*** thermal conductivity,density,heat capacity,and coefficient of thermal expansion obtained by the MD simulations were used in time-dependent thermal stress finite element model(FEM)*** low thermal conductivity(component diboride coupled with its similar coefficient of thermal expansion to that of graphite indicated that stresses of less than 10 GPa were generated at the interface at high temperatures,and therefore,the coating was mechanically resistant to the thermal stress induced during *** experiments at 220℃ showed that the multicomponent diboride coating was resistant to thermal stresses with no visible cracking or *** ablation mechanisms were mechanical denudation and evaporation of b_(2)O_(5) and light V-Ti oxides,which caused a decrease in the mass and thickness of the coating and resulted in mass and linear ablation rates of-0.51 mg·s^(-1) and -1.38μm·s^(-1),respectively,after 60 *** findings demonstrated the thermal and mechanical stability of multicomponent entropy-stabilized diborides as coatings for carbon materials in engineering components under extreme environments.

关键词： entropy-stabilized diborides ultrahigh temperature ceramics molecular dynamics(MD)simulations density functional theory(DFT) ablation properties

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Flexible impedance and capacitive tensile load sensor based on cNT composite

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chinese Physics b 2016年第2期25卷 568-572页

作者： Zubair Ahmad Kh s Karimov farid Touati Department of Electrical Engineering College of Engineering Qatar University Doha 2713 Qatar Ghulam Ishaq Khan Institute of Engineering sciences and Technology Topi District Swabi KPK 23640 Pakistan center for Innovative Development of science and New Technologies Academy of Sciences Aini St. 299/2 Dushanbe 734063 Tajikistan

In this paper, the fabrication and investigation of flexible impedance and capacitive tensile load sensors based on carbon nanotube（cNT） composite are reported. On thin rubber substrates, cNTs are deposited from suspension in water and pressed at elevated temperature. It is found that the fabricated load cells are highly sensitive to the applied mechanical force with good repeatability. The increase in impedance of the cells is observed to be 2.0 times while the decrease in the capacitance is found to be 2.1 times as applied force increases up to 0.3 N. The average impedance and capacitive sensitivity of the cell are equal to 3.4 N^（-1） and 1.8 N^（-1）, respectively. Experimental results are compared with the simulated values,and they show that they are in reasonable agreement with each other.

关键词： carbon nanotubes flexible tensile load impedance capacitive

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Theoretical study of Mechanism and Regioselectivity of 1,3-dipolar cycloaddition of N-[methyl]-c-[5-nitro-2-furyl] Nitrilimine with Dimethyl 7-oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylate

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chinese Journal of chemical Physics 2010年第2期23卷 165-168,I0001页

作者： farid Moeinpour 伊斯兰阿扎德大学理学院化学系阿巴斯港***伊朗

The mechanism and regioselectivity of 1,3-dipolar cycloaddition of N-[methyl]-c-[5-nitro-2-furyl] nitrilimine with dimethyl 7-oxabicyclo[2,2,1]hepta-2,5-diene-2,3-dicarboxylate were investigated using activation energy calculations and density functional theory-based reactivity indexes. The reaction proceeds by an asynchronous concerted mechanism. The calculations are performed at the b3LYP/6-31G（d） level of theory and the obtained results are in agreement with experimental outcome.

关键词： Regioselectivity 1 3-dipolar cycloaddition Nitrilimine DFT-based reactivity index b3LYP calculation

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Non-isolated step-up Dc-Dc converter based on switched capacitor cells

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csEE Journal of Power and Energy systems 2023年第3期9卷 1161-1172页

作者： farid Mohammadi Gevork b.Gharehpetian Hasan Rastegar Mohammad Farhadi-Kangarlu Amirkabir university of technology TehranIran Faculty of Electrical and computer Engineering Urmia UniversityUrmiaIran

A non-isolated high gain step-up Dc-Dc converter for low power applications is suggested in this *** the designed transformerless converter,the main switch current and voltage stress is reduced while maintaining high voltage *** instance,with a duty cycle of 0.5 a voltage gain equal to 5 is achieved while the normalized switch voltage stress is ***,it decreases power losses of active and passive *** the proposed converter design,the switched-capacitor(sc)technique is used to obtain maximum voltage transfer gain using only one *** three modes of operation,i.e.,continuous conduction mode(ccM),boundary conduction mode(bcM),and discontinuous conduction mode(DcM),are studied in *** small signal analysis(ssA)of the designed converter is investigated,and its steady-state model is examined under *** of the proposed converter proposed in this study is assessed and tested using a *** of the converter is recorded above 94%in a wide range of output ***,compared to the other converters,the results suggest satisfactory performance of the designed *** issue of the proposed converter is that its input current is not smooth due to using the switched-capacitor cell in its *** issue is alleviated by using input filters.

关键词： Dc-Dc converter high voltage gain nonisolated switched capacitor cell voltage stress

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Investigation into the Regiochemistry of 1,3-Dipolar cycloaddition of c,N-Diphenyl Nitrone with some Vinyl sulfoximines as Dipolarophile： Theoretical studies

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chinese Journal of chemistry 2011年第7期29卷 1429-1433页

作者： Moeinpour, farid Department of chemistry Faculty of Sciences Islamic Azad University Bandar Abbas Branch Bandar Abbas *** lran

The regiochemistry of 1,3-dipolar cycloaddition reactions of c,N-diphenyl nitrone with some vinyl sulfoximines as dipolarophile was investigated using density functional theory （DFT）-based reactivity indexes and activation energy calculations at b3LYP/6-31G（d） level of theory. Analysis of the geometries and bond orders （bOs） at the Ts structures associated with the different reaction pathways shows that these 1,3-dipolar cycloaddition reac- tions occur via an asynchronous concerted mechanism. Analysis of the local electrophilicity and nucleophilicity in- dexes permits an interpretation about the regioselectivity of these 1,3-dipolar cycloaddition reactions. The theoretical results obtained in the work clearly predict the regiochemistry of the isolated cycloadducts and agree to experimental outcomes.

关键词： regioselectivity cycloaddition density functional calculations

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Kinetics and mechanisms of the catalytic thermal cracking of asphaltenes adsorbed on supported nanoparticles

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Petroleum science 2016年第3期13卷 561-571页

作者： Tatiana Montoya blanca L.Argel Nashaat N.Nassar camilo A.Franco farid b.c.rtés Department of chemical and Petroleum Engineering University of Calgary 2500 University Drive NW CalgaryAB Canada Grupo de Investigacion Fenomenos de superficie-Michael Polanyi Facultad de Minas Universidad Nacional de Colombia Sede Medellin Medellin Colombia Grupo de Investigacion en Yacimientos de Hidrocarburos Facultad de Minas Universidad Nacional de Colombia Sede Medellfn Kra 80 No. 65-223 Medellfn Colombia

The production of heavy and extra-heavy oil is challenging because of the rheological properties that crude oil presents due to its high asphaltene *** upgrading and recovery processes of these unconventional oils are typically water and energy intensive,which makes such processes costly and environmentally *** catalysts could be used to enhance the upgrading and recovery of heavy oil under both in situ and ex situ *** this study,the effect of the Ni-Pd nanocatalysts supported on fumed silica nanoparticles on post-adsorption catalytic thermal cracking of n-c_7 asphaltenes was investigated using a thermogravimetric analyzer coupled with *** performance of catalytic thermal cracking of n-c_7asphaltenes in the presence of NiO and PdO supported on fumed silica nanoparticles was better than on the fumed silica support *** a fixed amount of adsorbed n-c_7asphaltenes（0.2 mg/m～2）,bimetallic nanoparticles showed better catalytic behavior than monometallic nanoparticles,confirming their synergistic *** corrected OzawaFlynn-Wall equation（OFW） was used to estimate the effective activation energies of the catalytic *** mechanism function,kinetic parameters,and transition state thermodynamic functions for the thermal cracking process of n-c_7 asphaltenes in the presence and absence of nanoparticles are investigated.

关键词： catalytic thermal cracking Adsorption Nanoparticles sHs n-c7 asphaltene

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On Modules satisfying the Descending chain condition on cyclic submodules

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Algebra colloquium 2020年第3期27卷 531-544页

作者： farid Kourki Rachid Tribak centre Regional des Metiers de l'Education et de la Formation(cRMEF)-Tanger Annexe de Larache B.P.4063LaracheMorocco centre Regional des Metiers de l'Education et de la Formation(cRMEF-TTH)-Tanger Avenue My Abdelaziz SouaniB.P.3117TangierMorocco

A module satisfying the descending chain condition on cyclic submodules is called *** class of coperfect modules lies properly bet ween the class of locally artinian modules and the class of semiartinian *** R be a commutative ring with *** show that every semiartinian Ti-module is coperfect if and only if R is a *** is also shown that the class of coperfect R-modules coincides with the class of locally artinian R-modules if and only if m/m^(2)is a finitely genera ted R-module for every maximal ideal m of R.

关键词： coperfect modules locally artinian modules perfect rings semiartinian modules(rings)

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Enhancement of magnesium-composite bond-interface by a simple combined abrasion and coating method

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Journal of Magnesium and Alloys 2019年第2期7卷 227-239页

作者： Davide De cicco farid Taheri Advanced composites and Mechanics Laboratory Department of Mechanical EngineeringDalhousie University1360 Barrington StreetPO Box 15000HalifaxNS B3H 4R2Canada

Obtaining a strong bond when adhering magnesium alloys to other materials,especially to fiber-reinforced polymer composites,is *** of the strength of the adhesive used,it is the surface preparation that also significantly affects the overall bond strength and long-term performance of the mated *** optimal and established surface preparations are available for aluminum,steel alloys and polymer composites,the current method proposed for magnesium alloys is extremely onerous,time-consuming,and very *** aim of the research disclosed in this paper has been to develop a relatively simple,effective and economical procedure for enhancing the bond strength between magnesium alloy to fiber-reinforced polymer composites,which had been proven to be a challenging *** proposed method facilitates a superior interface-bond using a relatively low-cost epoxy *** Mode I fracture toughness and delamination resistance are *** static and impact tests are used to assess the effectiveness of the proposed procedure.©2019 Published by Elsevier *** behalf of chongqing University.

关键词： bonding enhancement surface preparation 3D fiber-metal laminates Magnesium alloy

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On some n-c2 and strongly c2 Extensions

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Algebra colloquium 2020年第3期27卷 545-562页

作者： farid Kourki Jianlong chen Wenxi Li centre Regional des Metiers de「Education et de la Formation(cRMEF)-Tanger Annexe de Larache B.P.4063LaracheMorocco Department of Mathematics Southeast UniversityNanjing 210096China school of Mathematics and Physics Anhui University of Technology Ma^nshanAnhui 243002China

Let R be a ring and n be a positive *** R is called a left n-c2-ring(strongly left c2-ring)if every n-generated(finitely generated)proper right ideal of R has nonzero left *** discuss some n-c2 and strongly c2 extensi... 详细信息

关键词： n-self-associated module self-associated module n-c2-ring strongly c2-ring

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Numerical study of the near-wall vortical structures in particle-laden turbulent flow by a new vortex identification method-Liutex

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Journal of Hydrodynamics 2024年第1期36卷 53-60页

作者： farid Rousta Goodarz Ahmadi bamdad Lessani chaoqun Liu Department of Mechanical and Aerospace Engineering Clarkson UniversityPotsdamNYUSA Mechanical Engineering and Engineering science The University of North Carolina at CharlotteNCUSA Department of Mathematics University of Texas at ArlingtonArlingtonTXUSA

This study investigates turbulent particle-laden channel flows using direct numerical simulations employing the Eulerian-Lagrangian method.A two-way coupling approach is adopted to explore the mutual interaction between particles and fluid *** considered cases include flow with particle stokes number varying from st=2 up to st=100 while maintaining a constant Reynolds number of Reτ=180 across all cases.A novel vortex identification method,Liutex(Rortex),is employed to assess its efficacy in capturing near-wall turbulent coherent structures and their interactions with *** Liutex method provides valuable information on vortex strength and vectors at each location,enabling a detailed examination of the complex interaction between fluid and particulate *** widely acknowledged,the interplay between clockwise and counterclockwise vortices in the near-wall region gives rise to low-speed streaks along the *** low-speed streaks serve as preferential zones for particle concentration,depending upon the particle stokes *** is shown that the Liutex method can capture these vortices and identify the location of low-speed ***,it is observed that the particle stokes number(size)significantly affects both the strength of these vortices and the streaky structure exhibited by ***,a quantitative analysis of particle behavior in the near-wall region and the formation of elongated particle lines was carried *** involved examining the average fluid streamwise velocity fluctuations at particle locations,average particle concentration,and the normal velocity of particles for each set of particle stokes *** investigation reveals the intricate interplay between particles and near-wall structures and the significant influence of particles stokes *** study contributes to a deeper understanding of turbulent particle-laden channel flow dynamics.

关键词： Turbulent channel flow particle-laden flow direct numerical simulation(DNs) Eulerian-Lagrangian vortex identification turbulence coherent structures Liutex

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