Navegação Ciências Exatas e da Terra por Título
Resultados 3443-3462 de 5955
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Near-infrared coronal lines in narrow-line Seyfert 1 galaxies
(2002) [Artigo de periódico]We report spectroscopic observations in the wavelength region 0.8–2.4 μm aimed at detecting near-infrared coronal lines in a sample of five narrow-line and one broad-line Seyfert 1 galaxies. Our measurements show that [Si ... -
Near-infrared integrated spectra of Galactic globular clusters : testing simple stellar population models
(2011) [Artigo de periódico]We present SOAR/OSIRIS cross-dispersed near-infrared (NIR) integrated spectra of 12 Galactic globular clusters that are employed to test Maraston NIR evolutionary population synthesis models, and to provide spectral ... -
Near infrared photometric and optical spectroscopic study of 22 low mass star clusters embedded in nubulae
(2008) [Artigo de periódico]Aims. Among the star clusters in the Galaxy, those embedded in nebulae represent the youngest group, which has only recently been explored. The analysis of a sample of 22 candidate embedded stellar systems in reflection ... -
Near-infrared photometry of globular clusters towards the Galactic bulge : observations and photometric metallicity indicators
(2017) [Artigo de periódico]We present wide-field JHKS photometry of 16 Galactic globular clusters located towards the Galactic bulge, calibrated on the Two Micron All-Sky Survey photometric system. Differential reddening corrections and statistical ... -
Near-infrared spectral properties of star clusters and galactic nuclei
(1987) [Artigo de periódico]We present CCD spectra with 12.5 A resolution from 6300 to 9700 Å of 30 star clusters covering ranges 106 to 1.65 1010 yr in age, and -2.0 to 0.1 in metallicity, [Z/Zʘ]. As well, 62 galactic nuclei have been observed in ... -
Near-infrared study of new embedded clusters in the Carina complex
(2018) [Artigo de periódico]We analyse the nature of a sample of stellar overdensities that we found projected on the Carina complex. This study is based on the Two Micron All Sky Survey photometry and involves the photometry decontamination of field ... -
Near-infrared surface photometry of early-type galaxies
(2002) [Artigo de periódico]CCD infrared (JHKs) photometry was performed on a sample of 10 elliptical and 2 lenticular galaxies. Isophotal parameters, brightness profiles, integrated colors and color gradients arepresented. Color gradients found arevery ... -
Negative differential magnetization for Ni nanoparticles in Al
(2005) [Artigo de periódico]Using a layer-by-layer deposition technique, Ni thin films were sandwiched between AlOx layers in an Al matrix. By using x-ray-absorption spectroscopy, grazing incidence small-angle x-ray scattering, and highresolution ... -
Negative remanent magnetization of fine particles with competing cubic and uniaxial anisotropies
(1998) [Artigo de periódico]The magnetic properties of noninteracting single-domain particles whose anisotropy is made up of a cubic magnetocrystalline and a uniaxial components were investigated. Various directions of the uniaxial anisotropy were ... -
Negative rotatable anisotropy in IrMn/Cr/Co thin films
(2012) [Artigo de periódico]This work presents modifications of the magnetic properties of polycrystalline IrMn/Cr(tCr)/Co films where the Cr spacer thickness tCr was varied between 0.25 and 3 nm. High-resolution transmission electron microscopy, ... -
Nematic phase in stripe-forming systems within the self-consistent screening approximation
(2013) [Artigo de periódico]We show that in order to describe the isotropic-nematic transition in stripe-forming systems with isotropic competing interactions of the Brazovskii class it is necessary to consider the next to leading order in a 1/N ... -
Nematic phase in the J1-J2 square-lattice Ising model in an external field
(2015) [Artigo de periódico]The J1-J2 Ising model in the square lattice in the presence of an external field is studied by two approaches: the cluster variation method (CVM) and Monte Carlo simulations. The use of the CVM in the square approximation ... -
Nematic phase in two-dimensional frustrated systems with power-law decaying interactions
(2013) [Artigo de periódico]We address the problem of orientational order in frustrated interaction systems as a function of the relative range of the competing interactions. We study a spin model Hamiltonian with short-range ferromagnetic interaction ... -
Network growth for enhanced natural selection
(2009) [Artigo de periódico]Natural selection and random drift are competing phenomena for explaining the evolution of populations. Combining a highly fit mutant with a population structure that improves the odds that the mutation spreads through the ... -
Neural networks with high-order connections
(1993) [Artigo de periódico]We present results for two difFerent kinds of high-order connections between neurons acting as corrections to the Hopfield model. Equilibrium properties are analyzed using the replica mean-field theory and compared with ... -
Neutral current neutrino-nucleus interactions at high energies
(2009) [Artigo de periódico]We present a QCD analysis of the neutral current (NC) neutrino-nucleus interaction at the small-x region using the color dipole formalism. This phenomenological approach is quite successful in describing experimental results ... -
Neutralization and wake effects on the Coulomb explosion of swift H2+ ions traversing thin films
(2015) [Artigo de periódico]The Coulomb explosion of small cluster beams can be used to measure the dwell time of fragments traversing amorphous films. Therefore, the thickness of thin films can be obtainedwith the so-called Coulomb depth profiling ... -
Neutral pion and η meson production at midrapidity in Pb-Pb collisions at √sNN = 2.76 TeV
(2018) [Artigo de periódico]Neutral pion and η meson production in the transverse momentum range 1 < pT < 20 GeV/c have been measured at midrapidity by the ALICE experiment at the Large Hadron Collider (LHC) in central and semicentral Pb-Pb collisions ... -
Neutral pion and η meson production in p–Pb collisions at √sNN=5.02 TeV
(2018) [Artigo de periódico]Neutral pion and η meson invariant differential yields were measured in non-single diffractive p–Pb collisions at √ sNN = 5.02 TeV with the ALICE experiment at the CERN LHC. The analysis combines results from three ... -
Neutral polyampholyte in an ionic solution
(1996) [Artigo de periódico]The behavior of a neutral polyampholyte (PA) chain with N monomers, in an ionic solution, is analyzed in the framework of the full Debye-Hückel-Bjerrum-Flory (DHBjF) theory. A PA chain, that in addition to the neutral ...
