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Static and cyclic oxidation of Nb-cr-v-W-Ta high entropy alloy in air from 600 to 1400℃

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Journal of Materials Science & Technology 2020年第3期38卷 189-196页

作者： S.K.varma Francelia Sanchez Sabastian Moncayo c.v.Ramana Department Metallurgical Materials and Biomaterials EngineeringThe University of Texas at El PasoEl PasoTX79968-0520USA center for Advanced Materials Research(cMR) The University of Texas at El PasoEl PasoTX79968-0520USA

An oxidation resistance study has been made on Nb-cr-v-W-Ta high entropy alloy in a range of temperature from 600 to 1400℃in *** oxidation study has been performed for either(a)12 or 24 h of heating time or(b)3 or 10℃/min heating rates to the desired oxidation *** oxidation study conducted for three and a half days has been conducted at 600,700,and 800℃using 12 h of heating *** alloy can withstand the cyclic oxidation process with only a reasonable loss of *** identification of oxides indicates crystals of W and Ta oxides in cylindrical form while Nb and cr oxides show a nodular or granular morphology at both 1000 and 1200℃while and additional of oxide of v in whisker forms at 1200℃.

关键词： High entropy alloys Nb-cr-v-W-Ta Microstructures Oxidation

Dendritic spine degeneration:a primary mechanism in the aging process

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Neural Regeneration Research 2025年第6期20卷 1696-1698页

作者： Gonzalo Flores Leonardo Aguilar-Hernández Fernado García-Dolores Humberto Nicolini Andrea Judith vázquez-Hernández Hiram Tendilla-Beltrán Instituto de Fisiología Benemérita Universidad Autónoma de Puebla(BUAP)PueblaMexico Instituto de ciencias Forenses(INcIFO) Tribunal Superior de Justicia de la Ciudad de México(TSJCDMX).Mexico CityMexico Instituto Nacional de Medicina Genómica(INMEGEN) Mexico CityMexico

Recent reports suggest that aging is not solely a physiological process in living beings;instead, it should be considered a pathological process or disease(Amorim et al., 2022). consequently, this process involves a wide range of factors, spanning from genetic to environmental factors, and even includes the gut microbiome(GM)(Mayer et al., 2022). All these processes coincide at some point in the inflammatory process, oxidative stress, and apoptosis, at different degrees in various organs and systems that constitute a living organism(Mayer et al., 2022;AguilarHernández et al., 2023).

关键词： aging process stress

Influence of cobalt on performance of cu-ceO2 catalysts for preferential oxidation of cO

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Journal of Rare Earths 2020年第9期38卷 941-950,I0001页

作者： Sachin Malwadkar Parthasarathi Bera c.v.v.Satyanarayana catalysis Division CSIR-National Chemical LaboratoryPune 411008India Surface Engineering Division CSIR-National Aerospace LaboratoriesBengaluru 560017India

copper and cobalt oxides supported on ceO2 were investigated for preferential oxidation of carbon monoxide(cO-PROX)in the presence of excess hydrogen and cO2.(cuo)1-x(co3 O4)x/3-(ceO2)2.5(x=0,0.25,0.50,0.75,0.85 and 1)catalysts were prepared by coprecipitation *** mixed oxide catalysts were characterized by several physicochemical techniques,such as BET surface area(SBET),X-ray diffraction(XRD),high resolution transmission electron microscopy(HRTEM),temperature programmed reduction(TPR)and X-ray photoelectron spectroscopy(XPS).XRD studies show the peaks related to cuO and co3 O4 phases in copper and cobalt containing ceO2 *** average particle size of the ceO2 crystallites is in the range of 8-10 nm as evaluated from HRTEM *** studies demonstrate that cu,co and ce in(cuO)1-x(co3O4)x/3-(ceO2)2.5 catalysts are presented in+2 and+1,+3 and+2 and+4 and+3 oxidation states,*** catalyst with x=0.75 shows better activity and selectivity towards *** the catalyst with only copper(cuO-ceO2,x=0)shows good activity but reverse water gas shift(RWGS)reaction is noticed at high *** the other hand,RWGS reaction is suppressed on the cobalt containing cuO-ceO2 *** on ceO2 with x=1 shows hardly any activity for PRoX reaction at low *** methanation activity is observed on cuO-ceO2 or co3O4-ceO2 *** contrast,combination of copper and cobalt on ceO2 shows methanation of cO where enhanced activity is observed with increasing in cobalt content.

关键词： cO-PROX cu-ceO2 XRD XPS Methanation H2O addition

Effect of sintering temperature on the chemical bonding,electronic structure and electrical transport properties of β-Ga_(1.9)Fe_(0.1)O_(3) compounds

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Journal of Materials Science & Technology 2021年第8期67卷 135-144页

作者： Swadipta Roy c.v.Ramana center for Advanced Materials Research(cMR) University of Texas at El PasoEl Paso500 W University AveEl PasoTX79968United States

A model system,which is based on iron(Fe)doped gallium oxide(Ga_(2)O_(3))(Ga_(1.9)Fe_(0.1)O_(3)),has been considered to elucidate the combined effect of transition-metal ion doping and processing temperature on the chemistry,local structure and chemical bonding,and electrical transport properties of a wide band gap oxide(Ga_(2)O_(3)).The Ga_(1.9)Fe_(0.1)O_(3) compounds were synthesized using standard high-temperature solid state reaction *** effect of processing conditions in terms of different calcination and sintering environments on the structural and electrical properties of Ga_(1.9)Fe_(0.1)O_(3) compounds is studied in *** characterization by Raman spectroscopy revealed that Ga_(1.9)Fe_(0.1)O_(3) compounds exhibit monoclinic crystal symmetry,which is quite similar to the intrinsic parental crystal structure,though Fedoping induces lattice *** temperature(T_(sint))which was varied in the range of 900-1200℃,has significant impact on the structure,chemical bonding,and electrical properties of Ga_(1.9)Fe_(0.1)O_(3) *** spectroscopic measurements indicate the proper densification of the Ga_(1.9)Fe_(0.1)O_(3) compounds achieved through complete Fe diffusion into the parent Ga_(2)O_(3) lattice which is evident at the highest sintering *** X-ray photoelectron spectroscopy validates the chemical states of the constituent elements in Ga_(1.9)Fe_(0.1)O_(3) *** electrical properties of Ga_(1.9)Fe_(0.1)O_(3) fully controlled by T_(sint),which governed the grain size and microstructural *** temperature and frequency dependent electrical measurements demonstrated the salient features of the Fe doped Ga_(2)O_(3) *** activation energy determined from Arrhenius equation is 0.5 e *** results demonstrate that control over structure,morphology,chemistry and electrical properties of the Ga_(1.9)Fe_(0.1)O_(3) compounds can be achieved by optimizing T_(sint).

关键词： Ga_(2)O_(3)compounds Fe-doping Raman spectroscopy chemical bonding Electrical properties

Size Effects of the critical Temperature in Ferroelectric Thin Films

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communications in Theoretical Physics 2007年第7期48卷 183-188页

作者： v.c.Lo Institute of Physics and center for condensed Matter Physics Chinese Academy of SciencesBeijing 100080China

The size effects of the critical behaviors for the systems of interacting spins are discussed extensively *** this paper,the finite-size dependence of the critical temperature and susceptibility of the ferroelectric thinfilm are investigated numerically based on the four-state Potts model with the nearest-neighbor interactions between thedipole *** four orientations of the domains exist in the ferroelectric film and the movement of the domainwalls determines the polarization switching process besides the boundary conditions of the *** critical exponentsare obtained and our investigations show that the boundary conditions play the important roles for the ferroelectricproperties of the thin films and the critical behavior of the thin films strongly depends on the feature of the surface.

关键词： ferroelectric thin film critical temperature size effects

Improvements in tribological and anticorrosion performance of porous Ti–6Al–4v via PEO coating

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Friction 2021年第5期9卷 1303-1318页

作者： c.Garcia-cabezón M.L.Rodríguez-Méndez v.AmigóBorrás R.Bayón c.Salvo-comino c.Garcia-Hernandez F.Martin-Pedrosa Materials Engineering E.I.I.Universidad de ValladolidValladolid 47011Spain BioecoUvA Research Institute Universidad de ValladolidValladolid 47011Spain Group UvASENS Escuela de Ingenierías IndustrialesUniversidad de ValladolidValladolid 47011Spain Instituto de Tecnología de Materials Univesitat Politécnica de ValenciaValencia 46022Spain Tribology Unit Fundación IK4-TeknikerEibar 20600Spain

Medical implants manufactured using biomaterial Ti–6Al–4v exhibit some *** higher elastic modulus than that of natural bone can cause stress shielding *** can be avoided using Ti–6Al–4v with pores in the implant ***,poor corrosion and tribocorrosion behaviors are yielded because of the large area exposed to the *** mitigate both issues,coating technologies can be *** plasma electrolytic oxidation(PEO)process is a cost‐effective process that has been used successfully in nonporous Ti *** this study,two PEO coatings with different amounts of ca/P are ***,reports regarding their application in porous materials are *** effects of PEO treatments on corrosion and tribocorrosion in Ti–6Al–4v powder metallurgy are analyzed *** porous materials provide an efficient surface for PEO coatings,as demonstrated via scanning electron microscopy(SEM)and atomic force microscopy(AFM),and the porosity of the substrates improved the adherence of the *** corrosion resistance measured via electrochemical impedance spectroscopy confirmed the beneficial effect of the coatings,particularly for long exposure *** lower roughness,small pore size,and more compact film observed in the PEO–ca/P sample resulted in favorable tribological and corrosion properties.

关键词： Ti‐based alloys corrosion tribocorrosion surface modification

Multifunctional A356 alloy/PKSAnp composites:Microstructure and mechanical properties

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Defence Technology（防务技术） 2020年第3期16卷 731-736页

作者： v.S.Aigbodion I.c.Ezema Department of Metallurgical and Materials Engineering University of NigeriaNsukkaNigeria

Mechanical properties and microstructure of multifunctional composites produced with palm kernel shell ash nano particle(PKSAnp)-A356 alloy composites was *** composites were produced using Double layer feeding stir casting method(DLF-ScM) by adding 1 wt%-4 wt.% *** microstructure,density,electrical and mechanical properties were *** results shows that there was a uniform distribution of the PKSAnp in A356 *** mismatch at the interface between the PKSAnp and A356 alloy was 4.26%.Improvement of 30.47%,41.91%,49.52%,40.90% and 65.09% were obtained for hardness values,tensile,yield strength,%elongation and impact energy at 4 wt% *** work has established that the developed composites can be used for multifunctional applications where combination of toughness and strength is vital.

关键词： PKSAnp A356 alloy Microstructure Electrical and mechanical properties

Analysis on critical Success Factors for Agile Manufacturing Evaluation in Original Equipment Manufacturing Industry-An AHP Approach

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chinese Journal of Mechanical Engineering 2016年第5期29卷 880-888页

作者： c Ajay Guru Dev v S Senthil Kumar Department of Mechanical Engineering CEG Anna University

Manufacturing industries are facing challenges in the implementation of agile manufacturing in their products and processes. Agility is widely accepted as a new competitive concept in the manufacturing sector in fulfilling varying customer demand. Thus, evaluation of agile manufacturing in industries has become a necessity. The success of an organisation depends on its ability to manage finding the critical success factors and give them special and continued attention in order to bring about high performance. This paper proposes a set of critical success factors （cSFs） for evaluating agile manufacturing considered appropriate for the manufacturing sector. The analytical hierarchy process （AHP） method is applied for prioritizing the success factors, by summarizing the opinions of experts. It is believed that the proposed cSFs enable and assist manufacturing industries to achieve a higher performance in agile manufacturing so as to increase competitiveness.

关键词： critical success factor analytic hierarchy process pairwise comparison

Enhanced saturation magnetization in La^(3+) doped Nico ferrites prepared by sol-gel auto-combustion method

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Journal of Rare Earths 2024年第8期42卷 1546-1554,I0005页

作者： Maddileti Jelli vidyasagar Thopudurthy Krishna Reddy c.v. Department of Physics Rayalaseema UniversityKurnoolA.P518007.Iindia Department of Physics Government PolytechnicRayachotiA.P516269India

Lanthanum doped nickel-cobalt nano ferrites with chemical formula Ni_(0.5)co_(0.5)LaxFe_(2-x)O_(4)(x=0.05,0,10,0.15 and 0,20) were prepared using a simple sol-gel auto combustion *** basic structural properties were determined by X-ray diffraction method and the formation of single phased spinel ferrite was *** crystalline size decreased from 25 to 11 nm and lattice parameter a increases with increase of La *** surface morphology of these ferrites was observed by field-emission scanning electron microscopy(FESEM) and agglomerated irregular grains are observed with increase of the rare earth element La ***-dispersive X-ray spectroscopy(EDX) result confirms the presence of the required *** Fourier transform infrared spectroscopy(FTIR) spectrum indicates the formation of the spinel ferrite structure with M-O *** direct band measurements from ultraviolet-visible spectroscopy(Uv-vis) spectroscopy indicate that the direct band gap decreases from 1.39 to 1.19 ev for x=0.05 to x=0.15,then increases to 1.28 ev for x=*** room temperature magnetic properties of these ferrites were studied by a vibrating sample magnetometer(vSM).The enhanced saturation magnetization of 49.73 emu/g is observed for x=0.10 and then saturation magnetizations are gradually decreased for x=0.15 and x=*** the remanent magnetization and coercivity also follow the same trend.

关键词： Ferrites Sol-gel auto combustion La doping Magnetic properties Rare earths