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Robust interface and excellent as-built mechanical properties of Ti–6Al–4V fabricated through laser-aided additive manufacturing with powder and wire

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 154-168页

作者： Fei Weng Guijun Bi Youxiang Chew Shang Sui Chaolin Tan Zhenglin Du Jinlong Su fern Lan Ng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong Engineering&Technology Research Center for Superhard MaterialSchool of Materials Science and EngineeringShandong UniversityJinan 250061China Institute of Intelligent Manufacturing Guangdong Academy of SciencesGuangzhou 510095China Singapore Institute of Manufacturing Technology 5 Cleantech Loop636732Singapore

The feasibility of manufacturing Ti-6Al-4V samples through a combination of laser-aided additive manufacturing with powder(LAAM_(p))and wire(LAAM_(w))was explored.A process study was first conducted to successfully circumvent defects in Ti-6Al-4V deposits for LAAM_(p) and LAAM_(w),*** the optimized process parameters,robust interfaces were achieved between powder/wire deposits and the forged substrate,as well as between powder and wire *** characterization results revealed the epitaxial prior β grains in the deposited Ti-6Al-4V,wherein the powder deposit was dominated by a finerα′microstructure and the wire deposit was characterized by lamellar α *** mechanisms of microstructure formation and correlation with mechanical behavior were analyzed and *** mechanical properties of the interfacial samples can meet the requirements of the relevant Aerospace Material Specifications(AMS 6932)even without post heat *** fracture occurred within the interfacial area,further suggesting the robust *** findings of this study highlighted the feasibility of combining LAAM_(p) and LAAM_(w) in the direct manufacturing of Ti-6Al-4V parts in accordance with the required dimensional resolution and deposition rate,together with sound strength and ductility balance in the as-built condition.

关键词： laser-aided additive manufacturing powder deposition wire deposition interfacial characteristic mechanical behavior

Solution of the Center Problem for a Class of Polynomial Differential Systems

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1685-1696页

作者： Chang Jian Liu Jaume Llibre Rafael ramírez Valentín ramírez School of Mathematics(Zhuhai) Sun Yat-sen UniversityZhuhai519086P.R.China Departament de Matemàtiques Universitat Autònoma de Barcelona08193BellaterraBarcelonaCataloniaSpain Departament d’Enginyeria Informàtica i Matemàtiques Universitat Rovira i VirgiliAvinguda dels Paiïsos Catalans 2643007TarragonaCataloniaSpain

Consider the polynomial differential system of degree m of the form x=-y(1+μ(a_(2)x-a_(1)y))+x(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),y=x(1+μ(a_(2)x-a_(1)y))+y(v(a_(1)x+a_(2)y)+Ω_(m-1)(x,y)),whereμandνare real numbers such that(μ^(2)+v^(2))(μ+v(m-2))(a_(1)^(2)+a_(2)^(2))≠m>2 andΩ_(m−1)(x,y)is a homogenous polynomial of degree m−1.A conjecture,stated in *** Equations 2019,suggests that whenν=1,this differential system has a weak center at the origin if and only if after a convenient linear change of variable(x,y)→(X,Y)the system is invariant under the transformation(X,Y,t)→(−X,Y,−t).For every degree m we prove the extension of this conjecture to any value ofνexcept for a finite set of values ofμ.

关键词： Center problem polynomial differential system

Flight feather moult in Western Marsh Harriers during autumn migration

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Avian Research 2019年第1期10卷 30-35页

作者： Juan ramírez Michele Panuccio MEDRAPTORS(Mediterranean Raptor Migration Network) DSTA-Department of Earth and Environmental Sciences University of Pavia

Background:Most of long-distance migratory raptors suspend moult during migration but detailed information is patchy for most of the Palearctic *** aim of this research is to verify if active moulting in migrating Western Marsh Harriers occurs and to quantify the extent of moulting along the season focusing on primary ***:During a whole post-breeding migration at the Strait of Messina in Southern Italy,we gathered information about symmetrical flight feather moult from 221 adults by taking pictures of raptors passing at close ***:We found active moulting primaries during autumn migration in 48.4% of our *** differences on the extension and timing among sex classes were recorded during the season,with adult females showing a more advanced moult stage than adult ***:The finding that the extension of the suspended moult was already defined in migratory individuals might be explained as an adaptation to minimize the energy required for moulting during migration.

关键词： Migration Moult Primary feather Raptors Western Marsh Harrier

A higher-order porous thermoelastic problem with microtemperatures

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Applied Mathematics and Mechanics(English Edition) 2023年第11期44卷 1911-1926页

作者： J.R.fernández R.QUINTANILLA Department of Applied Mathematics I University of VigoETSI de Telecomunicacion Campus As Lagoas Marcosende s/nVigo 36310Spain Department of Mathematics Polytechnical University of CatalunyaTerrassa 08222BarcelonaSpain

In this paper,we study a porous thermoelastic problem with microtemperatures assuming parabolic higher order in time derivatives for the thermal *** model is derived and written as a coupled linear ***,a uniqueness result is proved by using the logarithmic convexity method in the case that we do not assume that the mechanical energy is positive ***,the existence of the solution is obtained by introducing an energy function and applying the theory of linear semigroups.

关键词： higher order thermoelasticity microtemperature logarithmic convexity method existence and uniqueness

Neuroprotective effects of meloxicam on transient brain ischemia in rats:the two faces of anti-inflammatory treatments

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Neural Regeneration Research 2023年第9期18卷 1961-1967页

作者： Irene fernández Ugidos Paloma González-Rodríguez María Santos-Galdiano Enrique Font-Belmonte Berta Anuncibay-Soto Diego Pérez-Rodríguez JoséManuel Gonzalo-Orden Arsenio fernández-López Área de Biología Celular Instituto de BiomedicinaCampus de Vegazana s/nUniversidad de LeónLeónSpain Neural Therapies SL.Edif.Institutos de Investigación.Planta baja.Local B43.Campus de Vegazana s/n.León.Spain Department of Medicina Cirugía y Anatomía VeterinariaUniversity of LeónLeónSpain Department of Pharmacology Tulane University School of MedicineNew OrleansLAUSA Department of Neurology David Geffen School of Medicine at University of California(UCLA)Los AngelesCAUSA Department of Life Sciences Imperial College London(ICL)LondonUK Department of Clinical and Movement Neurosciences UCL Queen Square Institute of NeurologyLondonUK

The inflammato ry response plays an important role in neuroprotection and regeneration after ischemic *** use of non-ste roidal anti-inflammatory drugs has been a matter of debate as to whether they have beneficial or detrimental *** this context,the effects of the anti-inflammatory agent meloxicam have been scarcely documented after stro ke,but its ability to inhibit both cyclooxygenase isoforms(1 and 2) could be a promising strategy to modulate postischemic *** study analyzed the effect of meloxicam in a transient focal cerebral ischemia model in rats,measuring its neuroprotective effect after 48 hours and 7 days of reperfusion and the effects of the treatment on the glial scar and regenerative events such as the generation of new progenitors in the subventricular zone and axonal sprouting at the edge of the damaged *** show that meloxicam’s neuroprotective effects remained after 7 days of reperfusion even if its administration was restricted to the two first days after ***,meloxicam treatment modulated glial scar reactivity,which matched with an increase in axonal ***,this treatment decreased the formation of neuronal progenitor *** study discusses the dual role of anti-inflammatory treatments after stro ke and encourages the careful analysis of both the neuroprotective and the regenerative effects in preclinical studies.

关键词： anti-inflammatories astrocyte axonal sprouting cylinder test doublecortin focal brain ischemia glial scar inflammation neuroprotection new neuron generation transient stroke

Artificial muscles driven by the cooperative actuation of electrochemical molecular *** discrepancies and challenges

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International Journal of Smart and Nano Materials 2017年第4期8卷 125-143页

作者： Toribio fernández Otero Laboratory of Electrochemistry Intelligent Materials and DevicesUniversidad Politécnica de Cartagena.Aulario IIICampus Alfonso XIIICartagenaSpain

Here we review the persisting conceptual discrepancies between different research groups working on artificial muscles based on conducting polymers and other electroactive *** basic question is if they can be treated as traditional electro-mechanical(physical)actuators driven by electric fields and described by some adaptation of their physical models or if,replicating natural muscles,they are electro-chemo-mechanical actuators driven by electrochemical reaction of the constitutive molecular machines:the polymeric *** that case the charge consumed by the reaction will control the volume variation of the muscular material and the motor displacement,following the basic and single Faraday’s laws:the charge consumed by the reaction determines the number of exchanged ions and solvent,the film volume variation to lodge/expel them and the amplitude of the *** from the linear relationships are due to the osmotic exchange of solvent and to the presence of parallel reactions from the electrolyte,which originate creeping *** and limitations are underlined.

关键词： Electromechanical actuator electro-chemo-mechanical artificial muscle molecular machines creeping osmotic effects

Multi-isotope and geochemical approach to the magma source and tectonic setting of Proterozoic anorthosite massifs and AnorthositeMangerite-Charnockite-Granite(AMCG)suites

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Geoscience Frontiers 2024年第6期15卷 2-21页

作者： L.A.Elizondo-Pacheco L.A.Solari R.González-Guzmán H.L.He E.Becerra-Torres J.A.ramírez-fernández R.Maldonado Posgrado en Ciencias de la Tierra Instituto de GeocienciasUniversidad Nacional Autónoma de MéxicoSantiago de Querétaro 76230Mexico Instituto de Geociencias Universidad Nacional Autónoma de MéxicoSantiago de Querétaro 76230Mexico Departamento de Geología División de Ciencias de la TierraCICESEEnsenada 22860Mexico School of Earth Sciences Yunnan UniversityKunming 650500PR China Yunnan International Joint Laboratory of Critical Mineral Resource Kunming 650500PR China Escuela Nacional de Estudios Superiores Unidad Juriquilla Universidad Nacional Autónoma de MéxicoSantiago de Querétaro 76230México Facultad de Ciencias de la Tierra Universidad Autónoma de Nuevo LeónLinares 67700Mexico Instituto de Geología Universidad Nacional Autónoma de MéxicoCiudad de México 04510Mexico

The occurrence of massif-type anorthosite intrusions is a widespread Proterozoic *** are usually associated with gabbroic,charnockitic,and granitic rocks,comprising the so-called anorthositemangerite-charnockite-granite(AMCG)*** these rocks have been extensively studied worldwide,several aspects concerning their formation remain *** them,the magma source and the tectonic setting are the most *** evaluate these issues,we first compiled geochemical and isotopic data of Proterozoic anorthosite massifs and AMCG suites worldwide and stored it in a database named *** plethora of data allows us to make some important *** argue that the wide-ranging multi-isotopic composition of this group of rocks reflects varying proportions of juvenile mantle-derived melts and crustal *** interpret that the precursor magmas of most massive anorthosite bodies and associated mafic rocks have a mantle-dominated ***,we highlight that a crustal component is indispensable to generate these *** variable amounts of this material during succeeding multi-stage assimilation-fractional crystallization(AFC)processes gives these intrusions their typical mantle-crustal hybrid isotopic *** contrast,a crustaldominant origin with a complementary mantle component is interpreted for most MCG *** summary,the isotopic information in datAMCG indicates that both sources are necessary to generate AMCG ***,we suggest that hybridized magmas with different mantle-crust proportions originate these *** interpretation might offer a more nuanced and accurate depiction of this phenomenon in future work instead of choosing a single-sourced model as in the past ***,tectonomagmatic diagrams suggest that the rocks under study were likely generated in a tectonic environment that transitioned between collision and post-collisional extension,sometimes involving subduction-modified ma

关键词： Massif-type anorthosite Anorthosite-granite suite Magmatic sources Hybridized magmas Tectonic setting Post-orogenic extension

Modeling the Spike Response for Adaptive Fuzzy Spiking Neurons with Application to a Fuzzy XOR

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Computer Modeling in Engineering & Sciences 2018年第6期115卷 295-311页

作者： A.M.E.ramírez-Mendoza CONACYT Research Fellow–State University of Nuevo León(UANL for its acronym in Spanish) Mechanical and Electrical Engineering School(FIME for its acronym in Spanish)Center for Research and Innovation in Aeronautical Engineering(CIIIA for its acronym in Spanish)Carretera a Salinas Victoria km.2.3ApodacaNuevo LeónMéxico

A spike response model(SRM)based on the spikes generator circuit(SGC)of adaptive fuzzy spiking neurons(AFSNs)is *** SRM is simulated in MatlabTM *** proposed model is applied to a configuration of a fuzzy exclusive or(fuzzy XOR)operator,as an illustrative example.A description of the comparison of AFSNs with other similar methods is *** novel method of the AFSNs is used to determine the value of the weights or parameters of the fuzzy XOR,first with dynamic weights or self-tuning parameters that adapt continuously,then with fixed weights obtained after training,finally with fixed weights and a dynamic gain or self-tuning gain for a fine adjustment of amplitude.

关键词： Spike response model spikes generator circuit fuzzy XOR adaptive fuzzy spiking neuron learning algorithm fuzzy neuron self-tuning

Frontier of the Paleo-Tethys Ocean in the western Mediterranean:Isotopic(Sm-Nd)constraints on sources of Devonian units from Menorca Island

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Geoscience Frontiers 2024年第5期15卷 323-338页

作者： Ricardo Arenas Jose M.Fuenlabrada Cristian Timoner Rubén Díez fernández Esther Rojo-Pérez Departamento de Mineralogía y Petrología and Instituto de Geociencias(UCM CSIC)Universidad ComplutenseMadridSpain Unidad de Geocronología(CAI de Ciencias de la Tierra y Arqueometría) Universidad ComplutenseMadridSpain Bayerisches Geoinstitut University of BayreuthBayreuthGermany Instituto Geológico y Minero de España–CSIC SalamancaSpain

The c.1000-m-thick pre-orogenic Devonian mainly metapelitic sequence of North Menorca Island shows a fairly complete stratigraphic *** rocks of this sequence indicate gradually increasing deeper marine conditions of sedimentation towards its uppermost ***,the obtained sedimentary characteristics resemble those related to a deep and narrow basin-associated *** sills of Ti-augite-bearing alkaline gabbros occur within the Devonian *** intensity of Variscan deformation increases downwards through the *** to the characteristics of the Devonian sequence and its location within the Variscan Orogen,a correlation with similar units located in the southern sectors of the Central Iberian Zone(Iberian Massif)is *** Devonian metapelitic rocks have geochemical characteristics suggesting that they represent moderately recycled mature siliciclastic sediments,generated from erosion of distant source areas belonging to an upper continental *** relatively narrow range of variation observed in initial^(143)Nd/^(144)Nd ratios supports a similar source for the Menorcan slates(0.51165–0.51182).However,a marked trend is observed in these isotope ratios,from lower values at the base of the stratigraphic column(minimum value of 0.511941)to higher values at the top(maximum value of 0.512131).The^(147)Sm/^(144)Nd ratios vary between 0.1074 and 0.1238,within the range defined for siliciclastic rocks with felsic crustal *** Nd model ages define a narrow range between 1496 Ma and 1754 Ma(Late Paleoproterozoic–Early Mesoproterozoic),and they are consistently younger *** data rule out a provenance from the erosion of the West Africa Craton,as they are more compatible with a provenance from regions located in the Trans-Saharan Belt or Sahara *** characteristics of the Menorcan Devonian sequence are compatible with its deposition in a narrow and deep peri-Gondwanan transtensional basin,gener

关键词： Western Paleo-Tethys frontiers Menorca Island Sm-Nd isotopic constraints Devonian sequence provenance in Gondwana