Navegação Ciências Exatas e da Terra por Título

Resultados 2905-2924 de 5948

    • Machine learning partners in criminal networks 

      Lopes, Diego Domingues; Cunha, Bruno Requião da; Martins, Alvaro F.; Goncalves, Sebastian; Lenzi, Ervin Kaminski; Hanley, Quentin S.; Perc, Matjaž; Ribeiro, Haroldo Valentin (2022) [Artigo de periódico]
      Recent research has shown that criminal networks have complex organizational structures, but whether this can be used to predict static and dynamic properties of criminal networks remains little explored. Here, by combining ...

    • Macro and microminerals are frozen fruits a good source? 

      Spada, Patricia Kelly Wilmsen Dalla Santa; Bortolini, Giovana Vera; Pra, Daniel; Santos, Carla Eliete Iochims dos; Henriques, João Antonio Pêgas; Dias, Johnny Ferraz; Salvador, Mirian (2010) [Artigo de periódico]
      As frutas são ricas em minerais, sendo estes essenciais para uma grande variedade de processos metabólicos e fisiológicos no corpo humano. A utilização de frutas congeladas tem se ampliado nos últimos anos, não só na ...

    • Macroscopic and microscopic perspectives for adoption of technologies in the USA 

      Carvalho, Alexsandro Marian; Goncalves, Sebastian; Ruffoni, Janaina Passuello; Iglesias, Jose Roberto (2020) [Artigo de periódico]
      Adoption of a new technology depends on many factors. Marketing, advertising, social interactions, and personal convictions are relevant features when deciding to adopt, or not, a new technology. Thus, it is very important ...

    • Macroscopic diagnostics of microscopic friction phenomena 

      Dahmen, Silvio Renato; Farkas, Zénó; Hinrichsen, Haye; Wolf, Dietrich Emil (2005) [Artigo de periódico]
      We show that the static friction force which must be overcome to render a sticking contact sliding is reduced if an external torque is also exerted. As a test system we study a planar disk lying on a horizontal flat surface. ...

    • Macrozoneamento do Estado do Rio Grande do Sul 

      Guasselli, Laurindo Antônio; Saldanha, Dejanira Luderitz; Suertegaray, Dirce Maria Antunes; Ducati, Jorge Ricardo; Fontana, Denise Cybis (2006) [Artigo de periódico]
      Earth imaging technologies using orbital platforms have allowed new approaches in the analyses, compartmentalization, and territorial visualization. These cartographic informations have many applications in agricultural, ...

    • Magmatic epidote and amphibole from the Rio Espinharas hybrid complex, Northeastern Brazil 

      Campos, Thomas Ferreira da Costa; Neiva, Ana Margarida Ribeiro; Nardi, Lauro Valentim Stoll; Pereira, Luciano Schaefer; Bonzanini, Leonardo Andre Fraga; Petta, Reinaldo Antonio; Meyer, Franz Michael (2005) [Artigo de periódico]
      The petrography and chemistry of epidote and amphibole from the Rio Espinharas hybrid complex (REHC), northeastern Brazil are reported. The Rio Espinharas complex is composed of an intimate association of diorite to ...

    • Magnesium surface enrichment of CoFe2O4 magnetic nanoparticles immobilized with gold : reusable catalysts for green oxidation of benzyl alcohol 

      Abreu, Wiury Chaves de; Garcia, Marco Aurélio Suller; Nicolodi, Sabrina; Moura, Carla Verônica Rodarte de; Moura, Edmilson Miranda de (2018) [Artigo de periódico]
      Gold nanoparticles have shown excellent activity for selective oxidation of alcohols; such catalytic systems are highly dependent on the initial activation of the substrates, which must occur on the catalyst surface in ...

    • Magnetically stimulable graphene oxide/polypropylene nanocomposites 

      Nisar, Muhammad; Galland, Griselda Ligia Barrera; Geshev, Julian Penkov; Bergmann, Carlos Perez; Quijada, Raul (2023) [Artigo de periódico]
      Core–shell magnetic air-stable nanoparticles have attracted increasing interest in recent years. Attaining a satisfactory distribution of magnetic nanoparticles (MNPs) in polymeric matrices is difficult due to magnetically ...

    • Magnetic and orbital ordering of RuO/sub 2/ planes in RuSr/sub 2/ (Eu,Gd) Cu/sub 2/O/sub 8/ 

      Aligia, Armando A.; Gusmao, Miguel Angelo Cavalheiro (2004) [Artigo de periódico]
      We start from an effective Hamiltonian for Ru ions in a square lattice, which includes the on-site interactions between t2g orbitals derived from Coulomb repulsion, and a tetragonal crystal-field splitting. Using perturbation ...

    • Magnetic and structural properties of Fe-implanted cubic GaN 

      Righetti, V. A. N.; Gratens, Xavier P. M.; Chitta, Valmir Antonio; De Godoy, Marcio F.; Rodrigues, Ariano De Giovanni; Abramof, Eduardo G.; Dias, Johnny Ferraz; Schikora, Detlef; As, Donat Josef; Lischka, Klaus (2016) [Artigo de periódico]
      In this article, we report on structural and magnetic properties of cubic GaN epitaxial layers implanted with Fe ions and subsequently subjected to thermal annealing. The epitaxial quality of the layers was studied by X-ray ...

    • Magnetic and structural properties of ion nitrided stainless steel 

      Basso, Rodrigo Leonardo de Oliveira; Pimentel, Vinicius do Lago; Weber, Sylvain; Marcos, Grégory; Czerwiec, Thierry; Baumvol, Israel Jacob Rabin; Figueroa, Carlos Alejandro (2009) [Artigo de periódico]
      The magnetic properties and crystalline structure of expanded austenite obtained by ion beam nitriding of AISI 316 steel are investigated. Magnetic force microscopy reveals that the nitrogen expanded austenite has two ...

    • Magnetic behavior of the NixFe1−xNb2O6 quasi-one-dimensional system : isolation of Ising chains by frustration 

      Sarvezuk, Paulo Willian Carvalho; Gusmao, Miguel Angelo Cavalheiro; Cunha, Joao Batista Marimon da; Isnard, Olivier (2012) [Artigo de periódico]
      Physical properties of the NixFe1−xNb2O6 compounds are investigated combining x-ray and neutron powder diffraction with magnetic and calorimetry measurements as well as 57Fe Mössbauer spectroscopy. This system is known to ...

    • Magnetic breakdown and phase-coherent galvanomagnetic effects 

      Silva, Cylon Eudoxio Tricot Goncalves da; Falicov, Leo M. (1973) [Artigo de periódico]
      This paper presents a generalization of Pippard's network-model approach for the calculation of transport properties in metals in the presence of magnetic breakdown and partial phase coherence of the wave function. The ...

    • Magnetic dichroism in core-level photoemission from Gd(0001) 

      Morais, Jonder; Fecher, Gerhard H.; Denecke, Reinhard; Hussain, Zahid; Fadley, Charles S. (2000) [Artigo de periódico]
      This work reports on magnetic dichroism in photoemission from the Gd 4l(l=s,p,d, f) core level of in-plane magnetized Gd films excited with linearly, circularly, and unpolarized light. Thin Gd films of about 100 ML thickness ...

    • Magnetic-field-dependent morphology of self-organized Fe on stepped Si(111) surfaces 

      Santos, Mauricio Cougo dos; Geshev, Julian Penkov; Pereira, Luis Gustavo; Schmidt, Joao Edgar (2009) [Artigo de periódico]
      The present work reports on Fe thin films grown on vicinal Si(111) substrates via rf magnetron sputtering. The dependencies of the growth mode and magnetic properties of the obtained iron nanostructures on both crystallographic ...

    • Magnetic interactions in the ludwigite Ni/sub 2/FeO/sub 2/BO/sub 3/ 

      Fernandes, Joao Carlos; Guimaraes, Renato Bastos; Continentino, Mucio Amado; Borges, Hortencio A.; Sulpice, A.; Tholence, Jean-Louis; Siqueira, Jesumar Lopes; Zawislak, Luci Irene; Cunha, Joao Batista Marimon da; Santos, Carlos Alberto dos (1998) [Artigo de periódico]
      We present an investigation of the magnetic properties of the ludwigite Ni2FeO2BO3. This material is an oxyborate that presents in its crystalline structure subunits in the form of walls where the transition metal ions are ...

    • Magnetic materials enriched with strontium : a study of the use as catalysts in the transesterification reaction of babassu oil 

      Abreu, Wiury Chaves de; Moraes, Ana Flávia; Reis, Roberta Yonara Nascimento; Pinto, Bernardo Ferreira; Moura, Carla Verônica Rodarte de; Nicolodi, Sabrina; Moura, Edmilson Miranda de (2019) [Artigo de periódico]
      This work described a new magnetic material enriched with strontium as catalyst to produce babassu biodiesel. The use of magnetic materials has attracted attention due to easy and fast separation from reaction medium. ...

    • Magnetic ordering in YGd alloys 

      Pureur Neto, Paulo; Fert, Albert R.; Wendler, R.; Baberschke, Klaus (1985) [Artigo de periódico]
      We present magnetization and resistivity measurements on single crystals of yttrium doped with small concentrations of gadolinium (c = 1, 2, and 3 at. %). The low-field susceptibility exhibits a spin-glass-like sharp cusp ...

    • Magnetic properties of Nd/Fe double layers grown on Si(111) by electron beam evaporation 

      Fermin, Jose R.; Azevedo, Antonio; Rezende, Sergio Machado; Pereira, Luis Gustavo; Teixeira, Sergio Ribeiro (1998) [Artigo de periódico]
      In-plane ferromagnetic resonance (FMR) has been used to study the room-temperature magnetic and crystalline properties of Nd/Fe bilayers. Several samples were grown by electron beam evaporation onto Si(111) substrates, for ...

    • Magnetic susceptibility and specific heat of the anderson lattice : perturbative expansion around the atomic limit 

      Brunnet, Leonardo Gregory; Gusmao, Miguel Angelo Cavalheiro; Iglesias, Jose Roberto (1992) [Artigo de periódico]
      The Green's functions relevant to the periodic Anderson Hamiltonian are calculated via perturbation theory around the atomic limit. The approximation reproduces exact results in three different limits: zero bandwidth, zero ...