Navegação Ciências Exatas e da Terra por Título
Resultados 2887-2906 de 5955
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Low-extinction windows in the inner Galactic Bulge
(2002) [Artigo de periódico]We built K band extinction maps in the area of two candidate low-extinction windows in the inner Bulge: W0.2-2.1 at (l, b) = (0.25°, –2.15° ), and W359.4-3.1 at (l, b) = (359.40°, −3.10°). We employed JH Ks photometry from ... -
Low-frequency vibrations of soft colloidal glasses
(2010) [Artigo de periódico]We conduct experiments on two-dimensional packings of colloidal thermosensitive hydrogel particles whose packing fraction can be tuned above the jamming transition by varying the temperature. By measuring displacement ... -
Low-mass secondary-ion ejection from molecular solids by mev heavy ions : radial velocity distributions
(1996) [Artigo de periódico]Secondary ions sputtered in individual MeV ion impacts are analyzed in a high resolution time-of-flight mass spectrometer. The initial radial velocity distributions of low mass (up to m/z≈300 u) positive and negative ... -
Low-mass variable stars in the globular cluster NGC 6397
(2017) [Artigo de periódico]We have conducted a photometric survey of the globular cluster NGC 6397 in a search for variable stars. We obtained ∼11 h of time-resolved photometric images with one European Southern Observatory-Very Large Telescope using ... -
Low potential barrier height effects in magnetic tunneling junctions
(2007) [Artigo de periódico]This paper reports on the study of deposited (Ni81Fe19/AlOx /Co) magnetic tunnel junctions by magnetron sputtering, with the insulating layer obtained by plasma oxidation of Al. Concentration of the tunnel current in small ... -
Low signal-to-noise spectroscopy and surface photometry of two faint galaxies in the field of NGC 7479
(2003) [Artigo de periódico]We present low signal-to-noise spectroscopy and surface photometry of two small galaxies, detected in the field of the nearby asymmetric barred spiral NGC 7479, near a prolongation of the western arm that forms a faint ... -
Low temperature aging effects on the formation of Sn nanoclusters in SiO/sub 2/Si films and interfaces
(2007) [Artigo de periódico]The formation of Sn nanocrystals NCs in ion implanted SiO2 /Si films is investigated using Rutherford backscattering spectrometry and transmission electron microscopy. Low temperature and long time aging treatments followed ... -
Low-temperature ion-induced epitaxial growth of alfa-FeSi2 and cubic FeSi2 in Si
(1993) [Artigo de periódico]Ion-beam-induced epitaxial crystallization of amorphous Si implanted with Fe to 18 at. % peak concentration was studied. The structure of the specimen was characterized using transmission electron microscopy and Rutherford ... -
Low-temperature iron-nitride phase transformations induced by ion bombardment
(1996) [Artigo de periódico]We show that for the Fe–N system the combined use of ion irradiation and thermal annealing can lower the temperature for a given phase transformation. By Ar bombarding N-implanted Fe samples at 250 and 300 °C, we have ... -
Low temperature sensitivity CMOS transconductor based on GZTC MOSFET condition
(2016) [Artigo de periódico]Complementary Metal Oxide Semiconductor (CMOS) Transconductors, or Gm cells, are key building blocks to implement a large variety of analog circuits such as adjustable filters, multipliers, controlled oscillators and ... -
Low-voltage, low-area, nW-power CMOS digital-based biosignal amplifier
(2022) [Artigo de periódico]This paper presents the operation principle and the silicon characterization of a power efficient ultra-low voltage and ultra-low area fully-differential, digital-based Operational Transconductance Amplifier (OTA), suitable ... -
Ludwig Boltzmann e a arte de voar
(2006) [Artigo de periódico]Uma das facetas pouco conhecidas de Ludwig Boltzmann diz respeito a sua fascinação pela aviação. Em 1894, em uma palestra de muita repercussão, na qual fez voar pelo auditório uma réplica de uma aeronave, Boltzmann defendeu ... -
Luminous infrared galaxies. III. Multiple merger, extended massive star formation, galactic wind, and nuclear inflow in NGC 3256
(2000) [Artigo de periódico]We report detailed evidence for multiple merger, extended massive star formation, galactic wind, and circular/noncircular motions in the luminous infrared galaxy NGC 3256, based on observations of highresolution imaging ... -
Lung cancer : changes in histology, gender, and age over the last 30 years in Brazil
(2017) [Artigo de periódico]Objective: To describe the trends in tumor histology, gender and age among patients with non-small cell lung cancer (NSCLC) treated with lung resection. The histology of lung cancer has changed in developed countries, and ... -
A luta pela terra e a recriação dos espaços de vida de assentados na Campanha Gaúcha
(2013) [Artigo de periódico]A luta pelo acesso a terra no Brasil, organizada através de movimentos sociais, já é uma questão histórica e vem ganhando cada dia mais força. A conquista da terra para um assentado representa a construção de um “novo ... -
A luz do sol : um curso dirigido a crianças da regiao litorânea e a crianças veranistas
(1993) [Artigo de periódico]Resumo não disponível -
A luz sincrotron iluminando a formação de professores
(2020) [Artigo de periódico]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
(2001) [Artigo de periódico]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
(2011) [Artigo de periódico]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?
(1993) [Artigo de periódico]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 ...
