128 research outputs found
A one-dimensional model for the growth of CdTe quantum dots on Si substrates
Recent experiments involving CdTe films grown on Si(111) substrates by hot
wall epitaxy revealed features not previously observed [S. O. Ferreira
\textit{et al.}, J. Appl. Phys. \textbf{93}, 1195 (2003)]. This system, which
follows the Volmer-Weber growth mode with nucleation of isolated 3D islands for
less than one monolayer of evaporated material, was described by a peculiar
behavior of the quantum dot (QD) size distributions. In this work, we proposed
a kinetic deposition model to reproduce these new features. The model, which
includes thermally activated diffusion and evaporation of CdTe, qualitatively
reproduced the experimental QD size distributions. Moreover, the model predicts
a transition from Stranski-Krastanow growth mode at lower temperatures to
Volmer-Weber growth mode at higher ones characterized through the QD width
distributions.Comment: to appear in Physics Letters
PrevisĂŁo da vida Ăștil de concreto armado de alta resistĂȘncia com adição de metacaulim e sĂlica ativa em ambientes marinhos
Consistent interactions of dual linearized gravity in D=5: couplings with a topological BF model
Under some plausible assumptions, we find that the dual formulation of
linearized gravity in D=5 can be nontrivially coupled to the topological BF
model in such a way that the interacting theory exhibits a deformed gauge
algebra and some deformed, on-shell reducibility relations. Moreover, the
tensor field with the mixed symmetry (2,1) gains some shift gauge
transformations with parameters from the BF sector.Comment: 63 pages, accepted for publication in Eur. Phys. J.
Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy
We review HB stars in a broad astrophysical context, including both variable
and non-variable stars. A reassessment of the Oosterhoff dichotomy is
presented, which provides unprecedented detail regarding its origin and
systematics. We show that the Oosterhoff dichotomy and the distribution of
globular clusters (GCs) in the HB morphology-metallicity plane both exclude,
with high statistical significance, the possibility that the Galactic halo may
have formed from the accretion of dwarf galaxies resembling present-day Milky
Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the
second-parameter problem is presented. A technique is proposed to estimate the
HB types of extragalactic GCs on the basis of integrated far-UV photometry. The
relationship between the absolute V magnitude of the HB at the RR Lyrae level
and metallicity, as obtained on the basis of trigonometric parallax
measurements for the star RR Lyrae, is also revisited, giving a distance
modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are
studied. Finally, the conductive opacities used in evolutionary calculations of
low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and
Space Scienc
Haematophagic behavior in laboratory of Lutzomyia cruzi (Mangabeira) (Diptera: Psychodidae) in relation to three mammalian blood sources in Manaus, Brazil
Climate change and future scenarios for palisade grass production in the state of SĂŁo Paulo, Brazil
Influence of diameter measuring height on the adjustment of volume and biomass equations of cerrado in minas gerais
MatointerferĂȘncia em arroz de sequeiro. I: efeitos do espaçamento e da adubação nitrogenada nas concentraçÔes de nutrientes no arroz e nas plantas daninhas
Composição corporal e exigĂȘncias de energia para ganho de peso de caprinos MoxotĂł em crescimento
Reproductive biology of Synallaxis albescens (Aves: Furnariidae) in the cerrado of central Brazil
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