Browsing Exact and Earth Sciences by Title

Now showing items 2907-2926 of 5964

    • A luz sincrotron iluminando a formação de professores 

      Acioly, Vitor; Picoreti, Renan; Rocha, Tulio Costa Rizuti da; Azevedo, Gustavo de Medeiros; Santos, Antônio Carlos Fontes dos (2020) [Journal article]
      Este artigo apresenta as duas primeiras versões de um curso de formação em serviço para professores de física de Ensino Médio, em que eles visitam todos os espaços do maior complexo de laboratórios científicos brasileiros ...

    • Lyapunov minimizing measures for expanding maps of the circle 

      Contreras, Gonzalo; Lopes, Artur Oscar; Thieullen, Ph. (2001) [Journal article]
      We consider the set of maps f є Fα+=Uβ >αC1β of the circle which are covering maps of degree D, expanding, minxєS1 f ¹(x) > 1 and orientation preserving. We are interested in characterizing the set of suchmaps f which admit ...

    • Lyman α wing absorption in cool white dwarf stars 

      Rohrmann, R. D.; Althaus, Leandro Gabriel; Kepler, Souza Oliveira (2011) [Journal article]
      Kowalski & Saumon identified the missing absorption mechanism in the observed spectra of cool white dwarf stars as the Lyman α red wing formed by the collisions between atomic and molecular hydrogen and successfully explained ...

    • Lynga 7 : a new disk globular cluster? 

      Ortolani, Sergio; Bica, Eduardo Luiz Damiani; Barbuy, Beatriz (1993) [Journal article]
      We have observed Lyngå 7, previously catalogued as an open cluster, in B, V and I.The Colour Magnitude Diagrams (CMDs) show that it is old like a globular cluster, or an extremely old thick/old disk cluster. It has a red ...

    • 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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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) [Journal article]
      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 ...