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101.
102.
A.F. Ferrari M. Gomes A.C. Lehum J.R. Nascimento A.Yu. Petrov E.O. Silva A.J. da Silva 《Physics letters. [Part B]》2009
We develop the superfield approach to the effective potential in three dimensions and calculate the one-loop and two-loop Kählerian effective potential in commutative and noncommutative cases. 相似文献
103.
Lana Mara Rodrigues dos Santos Philippe Michelon Marcos Nereu Arenales Ricardo Henrique Silva Santos 《Annals of Operations Research》2011,190(1):165-180
In this article we propose a 0-1 optimization model to determine a crop rotation schedule for each plot in a cropping area.
The rotations have the same duration in all the plots and the crops are selected to maximize plot occupation. The crops may
have different production times and planting dates. The problem includes planting constraints for adjacent plots and also
for sequences of crops in the rotations. Moreover, cultivating crops for green manuring and fallow periods are scheduled into
each plot. As the model has, in general, a great number of constraints and variables, we propose a heuristics based on column
generation. To evaluate the performance of the model and the method, computational experiments using real-world data were
performed. The solutions obtained indicate that the method generates good results. 相似文献
104.
de S. Araujo J. de Oliveira R.M.S. de C. Gomes K.D. Farias R.G. da S.S. Sobrinho C.L. 《Latin America Transactions, IEEE (Revista IEEE America Latina)》2009,7(2):230-237
This work describes a educational tool developed in Java language for simulating a multi-static radar. This radar is used to identify the presence of an intruder inside a residence. In order to obtain high resolution, the radar operates with ultra-wideband pulses (Gaussian monocycle), which have maximum spectral amplitude at 1 GHz and half power bandwidth of approximately 1 GHz. For the estimation of the intruder's position, the optimization technique particle swarm optimization (PSO) is employed. The simulator allows that the users define the parameters to be used by the radar and obtain the estimation of the intruder's position. Besides that, the software automatically generates animations of the wave propagation inside the residence, graphics of the signal at the receiving points and a final report with all the information related to the simulations. 相似文献
105.
106.
N. K. Leite J. G. Santos R. F. Souza G. M. Cabianchi F. O. Xavier B. M. Gomes L. B. Silveira A. C. Oliveira A. F.R. Rodriguez P. C. Morais 《The European physical journal. Special topics》2008,153(1):45-48
In this study we demonstrate the usefulness of the
Photoacoustic Spectroscopy (PAS) in the investigation of water collected
from a natural site located within the Amazon region, Brazil, during the wet
to dry seasons transition (May/2006). The water samples were collected from
different stages along a hydrologic pathway including precipitation water
(Prec), groundwater (GW), through flow water (TF), overland flow water (OF),
and stream flow water (SW). The observed photoacoustic spectral features, in
the 0.3 to 1.0 μm wavelength region, fall within three distinct bands
(C, S, and L). We found band-C, band-S and band-L occurring in the spectral
range of 0.30 to 0.40 μm, 0.40 to 0.45 μm and 0.45 to 1.0 μm
regions, respectively. The photoacoustic features shift peak positions and
change intensities for all samples investigated, thus supporting the
proposal of PAS as a useful technique to investigate water samples from
natural environments. 相似文献
107.
Three exact Slater-type function (STO) integral transforms are presented. The STO-NG basis set can then be developed using either only 1s Gaussian functions, the same Gaussian exponents for each shell, or using the first Gaussian of each symmetry. The use of any of these three alternatives depends only on appropriate numerical integration techniques. 相似文献
108.
José R. B. Gomes Luísa M. P. F. Amaral Manuel A. V. Ribeiro da Silva 《Journal of Physical Organic Chemistry》2008,21(5):365-371
The standard (p0 = 0.1 MPa) molar enthalpy of formation of 3,4‐dimethylbenzophenone was derived from the standard molar energy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry. The Calvet high temperature vacuum sublimation technique was used to measure the enthalpy of sublimation of the compound. From these experimental parameters, the standard molar enthalpy of formation of 3,4‐dimethylbenzophenone, in the gaseous phase and at T = 298.15 K, was derived as ?(17.1 ± 2.9) kJ mol?1. Density functional theory was used to investigate the gas‐phase molecular energetics of the 12 dimethylbenzophenones. Molecular geometries and vibrational frequencies were computed at the B3LYP/6‐31G(d) level of theory. The larger 6‐311+G(2d,2p) basis set was used to compute the energy of all dimethylbenzophenones and of the other compounds that were considered for the estimation of the standard molar enthalpies of formation at T = 298.15 K. The calculations show that the 2,2′‐ and 4,4′‐dimethylbenzophenones are the least and most stable isomers, respectively. Finally, the calculated enthalpy of formation of the benzophenone that was also studied experimentally, 3,4‐dimethylbenzophenone, is ?16.7 kJ mol?1, which is in excellent agreement with the experimental result. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
109.
110.
Some scaling properties for a classical particle interacting with a time-dependent square-well potential are studied. The corresponding dynamics is obtained by use of a two-dimensional nonlinear area-preserving map. We describe dynamics within the chaotic sea by use of a scaling function for the variance of the average energy, thereby demonstrating that the critical exponents are connected by an analytic relationship. 相似文献