17,546 research outputs found
Multiplicação de sequóia (Sequoia sempervirens L.) em meio de cultura esterelizado com hipoclorito de sódio.
O objetivo desta pesquisa foi comparar a eficiência deste protocolo com o protocolo convencional, que utiliza a autoclavagem como método de esterilização, bem como analisar o comportamento de plantas de sequóia em meio de cultura esterilizado com hipoclorito de sódio.Suplemento. Edição dos Resumos do XVI Congresso Brasileiro de Floricultura e Plantas Ornamentais; III Congresso Brasileiro de Cultura de Tecidos e Plantas; I Simpósio de Plantas Ornamentais Nativas, Goiânia, set. 2007
Group theory for structural analysis and lattice vibrations in phosphorene systems
Group theory analysis for two-dimensional elemental systems related to
phosphorene is presented, including (i) graphene, silicene, germanene and
stanene, (ii) dependence on the number of layers and (iii) two stacking
arrangements. Departing from the most symmetric graphene space
group, the structures are found to have a group-subgroup relation, and analysis
of the irreducible representations of their lattice vibrations makes it
possible to distinguish between the different allotropes. The analysis can be
used to study the effect of strain, to understand structural phase transitions,
to characterize the number of layers, crystallographic orientation and
nonlinear phenomena.Comment: 24 pages, 3 figure
Temperature effect on (2+1) experimental Kardar-Parisi-Zhang growth
We report on the effect of substrate temperature (T) on both local structure
and long-wavelength fluctuations of polycrystalline CdTe thin films deposited
on Si(001). A strong T-dependent mound evolution is observed and explained in
terms of the energy barrier to inter-grain diffusion at grain boundaries, as
corroborated by Monte Carlo simulations. This leads to transitions from
uncorrelated growth to a crossover from random-to-correlated growth and
transient anomalous scaling as T increases. Due to these finite-time effects,
we were not able to determine the universality class of the system through the
critical exponents. Nevertheless, we demonstrate that this can be circumvented
by analyzing height, roughness and maximal height distributions, which allow us
to prove that CdTe grows asymptotically according to the Kardar-Parisi-Zhang
(KPZ) equation in a broad range of T. More important, one finds positive
(negative) velocity excess in the growth at low (high) T, indicating that it is
possible to control the KPZ non-linearity by adjusting the temperature.Comment: 6 pages, 5 figure
Comportamento de genótipos de girassol no município de Mata Roma, MA, no período de 2008 a 2011.
O objetivo deste trabalho foi avaliar o comportamento de genótipos de girassol no município de Mata Roma, com vistas à produção de grãos e óleo.bitstream/item/79281/1/CT231.pd
Magnetic properties of GdZn (T = Fe, Co) investigated by X-ray diffraction and spectroscopy
We investigate the magnetic and electronic properties of the GdZn
( = Fe and Co) compounds using X-ray resonant magnetic scattering (XRMS),
X-ray absorption near-edge structure (XANES) and X-ray magnetic circular
dichroism (XMCD) techniques. The XRMS measurements reveal that the
GdCoZn compound has a commensurate antiferromagnetic spin structure
with a magnetic propagation vector =
below the N\'eel temperature ( 5.7 K). Only the Gd ions carry a magnetic moment forming an
antiferromagnetic structure with magnetic representation . For the
ferromagnetic GdFeZn compound, an extensive investigation was
performed at low temperature and under magnetic field using XANES and XMCD
techniques. A strong XMCD signal of about 12.5 and 9.7 is observed
below the Curie temperature ( 85 K) at the Gd- and edges,
respectively. In addition, a small magnetic signal of about 0.06 of the
jump is recorded at the Zn -edge suggesting that the Zn 4 states are spin
polarized by the Gd 5 extended orbitals
Thermodynamic Optimization of Tube-Fin Evaporators Operating under Frosting Conditions
In this study, the method of entropy generation minimization (i.e., design aimed at facilitating both heat, mass and fluid flows) is used to improve the evaporator geometry (aspect ratio and fin density) considering the irreversibilities produced by the heat and mass transfer, and viscous flow processes. A fully algebraic semi-empirical model was put forward to simulate the thermal-hydraulic behavior of tube-fin evaporator coils running under frosting conditions. The model predictions were validated against experimental data from Silva (2012), showing a good agreement between calculated and measured counterparts, with errors within a ±5% band for the cooling capacity and the air flow rate. The optimization exercise pointed out that high aspect ratio heat exchanger designs lead to minimum entropy generation in cases of fixed heat duty and air flow rate constrained by the characteristic curve of the fan
Avaliação de clones de cajueiro-anão-precoce no cerrado do sul maranhense.
Avaliação de Clones de Cajueiro-Anão-Precoce no Cerrado do Sul Maranhense; Introdução; Desenvolvimento; Biometria; Produtividade; Características do fruto; Aptidão comercial; Distribuição média mensal da produção de castanha; Características agroeconômicas; Comercialização da produção; Comparativos econômicos.bitstream/item/37219/1/Doc145.pd
Desempenho produtivo de oito clones de cajueiro anão precoce cultivados no semi-árido piauiense sob regime de sequeiro.
bitstream/CPAMN-2009-09/17156/1/CT145.pd
Comportamento produtivo de oito clones de cajueiro-anão-precoce em cultivo de terceiro ano sob regime de sequeiro.
bitstream/item/38615/1/CT158.pd
Avaliação de clones de cajueiro-anão-precoce em cultivo de terceiro ano no semi-árido piauiense.
O objetivo deste trabalho foi avaliar o desempenho produtivo de oito clones de cajueiro anão precoce no semi-árido piauiense, visando identificar os mais promissores para a produção de castanha e caju para mesa..
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