10,294 research outputs found
Memory effects on the statistics of fragmentation
We investigate through extensive molecular dynamics simulations the
fragmentation process of two-dimensional Lennard-Jones systems. After
thermalization, the fragmentation is initiated by a sudden increment to the
radial component of the particles' velocities. We study the effect of
temperature of the thermalized system as well as the influence of the impact
energy of the ``explosion'' event on the statistics of mass fragments. Our
results indicate that the cumulative distribution of fragments follows the
scaling ansatz , where is
the mass, and are cutoff parameters, and is a scaling
exponent that is dependent on the temperature. More precisely, we show clear
evidence that there is a characteristic scaling exponent for each
macroscopic phase of the thermalized system, i.e., that the non-universal
behavior of the fragmentation process is dictated by the state of the system
before it breaks down.Comment: 5 pages, 8 figure
Generalized Ladder Operators for Shape-invariant Potentials
A general form for ladder operators is used to construct a method to solve
bound-state Schr\"odinger equations. The characteristics of supersymmetry and
shape invariance of the system are the start point of the approach. To show the
elegance and the utility of the method we use it to obtain energy spectra and
eigenfunctions for the one-dimensional harmonic oscillator and Morse potentials
and for the radial harmonic oscillator and Coulomb potentials.Comment: in Revte
Role of Quantum Confinement in Luminescence Efficiency of Group IV Nanostructures
Experimental results obtained previously for the photoluminescence efficiency
(PL) of Ge quantum dots (QDs) are theoretically studied. A
- plot of PL versus QD diameter () resulted in an
identical slope for each Ge QD sample only when . We
identified that above 6.2 nm: due to a changing
effective mass (EM), while below 4.6 nm: due to
electron/ hole confinement. We propose that as the QD size is initially
reduced, the EM is reduced, which increases the Bohr radius and interface
scattering until eventually pure quantum confinement effects dominate at small
Climate change in Mali en Brazil : towards an evaluation method of climate change and land use policies
Magnetic Properties of the Metamagnet Ising Model in a three-dimensional Lattice in a Random and Uniform Field
By employing the Monte Carlo technique we study the behavior of Metamagnet
Ising Model in a random field. The phase diagram is obtained by using the
algorithm of Glaubr in a cubic lattice of linear size with values ranging
from 16 to 42 and with periodic boundary conditions.Comment: 4 pages, 6 figure
Dimensionamento amostral para estimação de coeficientes de correlação em híbridos de milho, safras e níveis de precisão
Physical indicators of soil quality on management systems from Cerrado region in Minas Gerais State, Brazil.
Evaluating the reforested area for the municipality of Buri by automatic analysis of LANDSAT imagery
The author has identified the following significant results. The class of reforestation (Pinus, Eucalyptus, Araucaria) was defined using iterative image analysis (1-100) and LANDSAT MSS data. Estimates of class area by 1-100 were compared with data supplied by the forestry institute in Sao Paulo. LANDSAT channels 4 and 5 served to differentiate the Pinus, Eucalyptus, and Araucaria from the other trees. Channels 6 and 7 gave best results for differentiating between the classes. A good representative spectral response was obtained for Auraucaria on these two channels. The small relative differences obtained were +4.24% for Araucaria, -7.51% for Pinus, and -32.07% for Eucalyptus
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