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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKIlIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(lPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOl *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell lPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

BaTiO_(3)solid solutions co-doped with Gd^(3+)and Eu^(3+):Synthesis,structural evolution and dielectric properties

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Journal of Rare Earths 2024年第10期42卷 1920-1926页

作者： R.martínez-lópez m.Pérez-labra J.A.Romero-Serrano F.R.Barrientos-Hernández m.Reyes-Pérez m.I.Valenzuela-Carrillo G.Urbano-Reyes V.E.Reyes-Cruz G.I.Dávila-Pulido Academic Area of Earth Sciences and materials Autonomous University of Hidalgo StateRoad Pachuca-Tulancingo Km 4.5 Mineral de La Reforma.Hidalgo42184Mexico metallurgy and materials Department ESIQIE-IPNUPALMZacatencoCiudad de Mexico07738Mexico Autonomous University of Coahuila Boulevard Adolfo López Mateos S/nNueva RositaCoahuila26800Mexico

In this paper,the synthesis,structural evolution,and dielectric properties of BaTiO_(3)solid solutions codoped with rare earth elements(Gd^(3+)and Eu^(3+))prepared using the solid-state reaction method are *** pure precursor powders of BaCl_3,TiO_(2),Gd_(2)O_(3),and Eu_(2)O_(3)were mixed in stoichiometric proportions,ground in an agate mortar before being uniaxially pressed at 250 mPa and sintered at 1300℃in air atmosphere for 6 h to obtain Ba_(1-3x)Gd_(2x)Ti_(1-3x)Eu_(4x)O_(3)(x=0,0.0015,0.01 and0.1).X-ray diffraction(XRD)and Rietveld's refinement results reveal the crystal phase ferroelectric tetragonal BaTiO_(3)for the samples with x=0,0.0015 and 0.01,as well as a consistent increment in the lattice parameters caused by the *** solubility limit of Gd^(3+)and Eu^(3+)in the BaTiO_(3)structure is reached for the sample with x>0.01,and the orthorhombic Eu_2TiO_(5)and monoclinic BaTi_(2)O_(5)secondary phases were *** Raman results show the characteristic peaks of ferroelectric tetragonal BaTiO_(3)around 716 cm^(-1)(lO of A1 symmetry),515 cm^(-1)(TO of A1 symmetry),and 305 cm^(-1)(B1).The maximum relative permittivity measured at 1 kHz was recorded to be 6151.8 for the sample with x=0.0015,and a decrease in the Curie temperature to 105℃with respect to the undoped sample was *** punctual microanalysis for the samples with x=0.0015,0.01,and 0.1 reveals grains composed of Ba,Ti,O,Gd,and Eu homogeneously distributed in the BaTiO_(3)*** Ba/Ti ratios for samples with x=0.0015,0.01 and 0.1 are 2.86,2.91,and 0.68,respectively,indicating substitution at the Ti site for samples with x=0.0015 and 0.01 and a substitution at the Ba site for the sample with x=0.1.

关键词： BaTiO_(3) Doping Gadolinium Europium Synthesis Rare earths

Effect of Ta_(2)O_(5)nanoparticles on bioactivity,composition,structure,in vitro and in vivo behavior of PEO coatings on mg-alloy

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Journal of magnesium and Alloys 2024年第6期12卷 2360-2379页

作者： D.V.mashtalyar I.m.Imshinetskiy V.V.Kashepa K.V.Nadaraia m.A.Piatkova A.I.Pleshkova K.A.Fomenko A.Yu.Ustinov S.l.Sinebryukhov S.V.Gnedenkov Institute of Chemistry Far Eastern BranchRussian Academy of SciencesVladivostok690022Russia Far Eastern Federal University Vladivostok690950Russia Regional Clinical Dermatovenerological Dispensary Vladivostok690033Russia

The present study investigates the physical and chemical characteristics,behavior in vitro and in vivo,and biocompatibility of coatings containing Ta_(2)O_(5),which are obtained by plasma electrolytic oxidation(PEO)on mA8 magnesium *** obtained coatings demonstrate in vivo biocompatibility and in vitro *** to the base PEO coating,the layers containing Ta_(2)O_(5)facilitate the development of apatite in simulated body fluid,suggesting that the inclusion of nanoparticles improves bioactivity of the *** was found that incorporation of Ta_(2)O_(5)nanoparticles increases roughness and porosity of the formed layers by increasing particle concentration in electrolytes for the PEO process contributing to sufficient soft tissue ingrowth in *** on in vivo studies,these coatings also provide favorable tissue response and minimal inflammatory reaction in comparison with the bare magnesium alloy due to protection of living tissues from deleterious corrosion events of magnesium implant such as local alkalization and intense hydrogen *** results obtained in the present study concluded biocompatibility,tissue integration of the PEO coatings containing Ta_(2)O_(5)nanoparticles making them a promising protective layer for biodegradable magnesium implants.

关键词： Plasma electrolytic oxidation Bioactive coatings Tantalum pentoxide Simulated body fluid(SBF) Apatite formation Histology

Special Properties of morita Contexts

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Algebra Colloquium 2024年第2期31卷 309-322页

作者： Kamal Paykan l.A.Bokut Department of mathematics Tafresh UniversityTafreshIran 不详

In this paper we continue the study of various ring theoretic properties of morita *** and sufficient conditions are obtained for a general morita context or a trivial morita context or a formal triangular matrix ring to satisfy a certain ring property which is among being Kasch,completely primary,quasi-duo,2-primal,NI,semiprimitive,projective-free,*** also characterize when a general morita context is weakly principally quasi-Baer or strongly right mininjective.

关键词： morita context formal triangular matrix ring Kasch quasi-duo Köthe's conjecture weakly principally quasi-Baer

Cognition and movement in neurodegenerative disorders:a dynamic duo

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Neural Regeneration Research 2024年第10期19卷 2101-2102页

作者： marit F.l.Ruitenberg Department of Health Medical and NeuropsychologyLeiden UniversityLeidenthe Netherlands leiden Institute for Brain and Cognition Leidenthe Netherlands

People with neurodegenerative disorders often experience problems across a variety of functional domains,including cognition,movement,and psychosocial *** classification of these disorders is based on the phenotypical manifestations that represent the most prominent clinical *** example,Parkinson's disease and Huntington's disease are typically regarded as movement disorders,whereas Alzheimer's disease(AD) and other dementias are regarded as cognitive disorders.

关键词： disorders Huntington degenerative

modelling dynamic pantograph loads with combined numerical analysis

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Railway Engineering Science 2024年第1期32卷 81-94页

作者： F.F.Jackson R.mishra J.m.Rebelo J.Santos P.Antunes J.Pombo H.magalhaes l.Wills m.Askill School of Computing and Engineering University of HuddersfieldHuddersfieldUK School of Computing and Engineering Institute of Railway ResearchUniversity of HuddersfieldHuddersfieldUK IDmEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal ISEl Instituto Politecnico de LisboaLisbonPortugal Hitachi Rail Newton AycliffeUK Wabtec/Brecknell Willis ChardUK

Appropriate interaction between pantograph and catenary is imperative for smooth operation of electric *** heights of overhead lines to accommodate level crossings,overbridges,and tunnels pose significant challenges in maintaining consistent current collection performance as the pantograph aerodynamic profile,and thus aerodynamic load changes significantly with operational *** research aims to analyse the global flow characteristics and aerodynamic forces acting on individual components of an HSX pantograph operating in different configurations and orientations,such that the results can be combined with multibody simulations to obtain accurate dynamic insight into contact ***,computational fluid dynamics simulations are used to investigate the pantograph component loads in a representative setting,such as that of the recessed cavity on a Class 800 *** an aerodynamic perspective,this study indicates that the total drag force acting on non-fixed components of the pantograph is larger for the knuckle-leading orientation rather than the knuckle-trailing,although the difference between the two is found to reduce with increasing pantograph *** the aerodynamic loads acting on individual components with multibody tools allows for realistic dynamic insight into the pantograph *** results obtained show how considering aerodynamic forces enhance the realism of the models,leading to behaviour of the pantograph-catenary contact forces closely matching that seen in experimental tests.

关键词： Pantograph-catenary interaction Pantograph aerodynamics Computational fluid dynamics Pantograph loads Current collection performance

large dinosaur egg accumulations and their significance for understanding nesting behaviour

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Geoscience Frontiers 2024年第5期15卷 467-488页

作者： l.Ezquerro R.Coimbra B.Bauluz C.Núñez-lahuerta T.Román-Berdiel m.moreno-Azanza Departamento de Geodinámica Estratigrafía y PaleontologíaFacultad de Ciencias GeológicasUniversidad Complutense de MadridC/JoséAntonio Novais1228040MadridSpain Aragosaurus-IUCA:Recursos Geológicos y Paleoambientales.Departamento de Ciencias de la Tierra.Facultad de Ciencias Universidad de ZaragozaC/Pedro Cerbuna 1250009 ZaragozaSpain museu da lourinha LourinhaPortugal GeoBioTec Department of Earth SciencesNOVA School of Science and TechnologyUniversidade Nova de LisboaCaparicaPortugal GeoBioTec Departamento de GeocienciasUniversidade de AveiroAveiroPortugal Insitut Catalàde Paleoecologia Humana i EvolucióSocial(IPHES-CERCA) Zona Educacional 4Campus Sescelades URV(Edifici W3)43007 TarragonaSpain Departament d´Història i Història de l´Art Universitat Rovira i VirgiliAv.Catalunya 3543002 TarragonaSpain Geotransfer IUCA Departamento de Ciencias de La TierraFacultad de CienciasUniversidad de ZaragozaZaragozaSpain

The accurate identification of dinosaur egg accumulations as nests or clutches is crucial for understanding the reproductive behaviour of these extinct ***,existing methods often rely on the presence of complete eggs and embryo remains,and sedimentological criteria that are only applicable to well-structured *** this study,we introduce an innovative approach to characterize egg accumulations in structureless sediments,where traditional nest structures may not be *** methodology employs a unique combination of sedimentological,taphonomic,geochemical,and geophysical proxies for the study of egg *** applied this approach to the egg accumulation from Paimogo(Jurassic,Portugal),traditionally interpreted as a *** findings reveal that the Paimogo egg assemblage is a secondary deposit,resulting from a flooding event in a fluvial plain that dismantled several allosauroid and crocodylomorph *** eggshell vapor conductance results,coupled with sedimentological evidence,suggest that allosauroid dinosaurs buried their eggs in the dry terrain of overbank areas close to a main channel during the breeding season,likely during the dry season to prevent the embryos from *** research underscores the necessity of multidisciplinary approaches in interpreting egg accumulations and offers a novel methodology for studying these accumulations in structureless *** findings provide new insights into the breeding behaviour and nesting preferences of these extinct organisms,contributing to our understanding of dinosaur ecology.

关键词： Breeding behaviour Theropod Taphonomy Stable isotopes magnetic susceptibility Jurassic

Complex-frequency waves:beat loss and win sensitivity

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light(Science & Applications) 2024年第2期13卷 181-183页

作者： Qingqing Cheng Tao l School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China Department of Respiratory Diseases and Critical medicine Quzhou Hospital Affiliated to Wenzhou Medical UniversityQuzhou324000China National laboratory of Solid State microstructures College of Engineering and Applied SciencesNanjing UniversityNanjing210093China

Recent experiments have demonstrated that synthesized complex-frequency waves can impart a virtual gain to molecule sensing systems,which can effectively restore information lost due to intrinsic molecular *** enhancement notably amplifies the signal of trace molecular vibrational fingerprints,thereby substantially improving the upper limit of sensitivity.

关键词： thereby Complex limit

measuring Impact of lean manufacturing Tools for Continuous Improvement on Economic Sustainability

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Journal of Systems Science and Systems Engineering 2024年第4期33卷 452-474页

作者： luis Javier márquez Figueroa Jorge luis García-Alcaraz Ahmed I.Osman Alfonso Jesús Gil lópez Yashar Aryanfar mika Sillanpää mamdouh El Haj Assad Department of Electrical Engineering and Computer Science Universidad Autónoma de Ciudad JuárezCiudad JuárezChihuahuaMéxico Department of Industrial Engineering and manufacturing Universidad Autónoma de Ciudad JuárezCiudad JuárezChihuahuaMéxico School of Chemistry and Chemical Engineering Queens UniversityBelfastNorthern IrelandUK Department of Economic and managerial Sciences University of La RiojaLa RiojaSpain Department of Chemical Engineering University of JohannesburgJohannesburgSouth Africa Department of Sustainable and Renewable Energy Engineering University of SharjahSharjahUAE

Using lean manufacturing(lm)tools in production processes is crucial for companies’economic,environmental,and social sustainability *** study shows a structural equation model(SEm)that shows the relationship between lm Tools like Kaizen(KAI),Gemba(GEm),Value Stream mapping(VSm)and Key Performance Indicator(KPI)with Economic Sustainability(ECS).Seven hypotheses were evaluated with data from 179 responses to a questionnaire about the mexican maquiladora industry,showing that these variables are *** a 95%confidence level,the model was evaluated using the partial least squares *** findings indicate that the relationships between KAI and GEm and KAI and VSm have the strongest relationship,followed by VSm and ECS;however,VSm has the strongest effect on *** on these findings,it is recommended that managers adopt a continuous improvement(KAI)approach based on working directly on the shop floor(GEm and VSm)to support their decisions regarding economic growth(ECS).

关键词： lean manufacturing economic sustainability structural equation model quality improvement

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)la_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)la_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)la_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)la_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)la_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and la^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of la^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)la_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)la_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and la^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)la_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)la_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)la_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)la_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation