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Mostrando ítems 1-10 de 13
Artículo
A simple method for efficiency calibration of HPGe detectors in gamma-spectrometric measurements
(Elsevier, 2001)
In this paper a simple, rapid and general method for g-ray efficiency calibration of Ge detectors for environmental samples is presented. This method is based on the use of an active natural solid sample with several ...
Artículo
Sedimentary speciation of U and Th isotopes in a marsh area at the southwest of Spain
(Springer, 2001)
A study of the distribution of U and Th-isotopes in different fractions of intertidal sediments collected in a marsh area has been carried out. This marsh area is affected by the releases of natural radionuclides from ...
Artículo
Ra-226 in waters of an estuarine system formerly affected by direct discharges of wastes from a phosphate fertilizer processing complex
(Springer, 2001)
The presence of 226 Ra in an estuary formerly affected by direct discharges of waste from a phosphate fertilizer complex has been investigated. Specific activities ranging from 3.6 to 45.2 mBq/l have been detected. In ...
Artículo
Natural radioactivity in groundwaters around a fertilizer factory complex in South of Spain
(Elsevier, 2001)
A study ofthe concentration ofthe U isotopes, 226Ra and 230Th in a groundwater system has been carried out. This aquifer, located in the provinces of Sevilla and Huelva, is the most important in the south of Spain having ...
Artículo
Artículo
Fourier state of a fluidized granular gas
(European Physical Society, 2001)
It is shown that the Boltzmann equation for smooth inelastic hard disks or spheres admits a solution describing a steady state characterized by uniform pressure and linear temperature profile. Such a state has been observed ...
Artículo
Nonequivalence of phonon modes in the sine-Gordon equation
(2001)
We study the resonances in the sine-Gordon equation driven by an ac force using a linear perturbation theory. We show that resonances take place when the driving frequency d is equal to half of the phonon modes’ frequencies ...
Artículo
Numerical study of breathers in a bent chain of oscillators with long-range interaction
(IOP Science, 2001)
Most of the studies of breathers in networks of oscillators are limited to nextneighbour interaction. However, long-range interaction becomes critical when the geometry of the chain is taken into account, as the distance ...
Artículo
Interplay of nonlinearity and geometry in a DNA-related, Klein-Gordon model with long-range dipole-dipole interaction
(American Physical Society, 2001)
Most of the studies on mathematical models of DNA are limited to next neighbor interaction. However, the coupling between base pairs is thought to be caused by dipole interaction, and, when the DNA strand is bent, the ...
Artículo
Numerical study of two-dimensional disordered Klein-Gordon lattices with cubic soft anharmonicity
(2001)
Localized oscillations appear both in ordered nonlinear lattices (breathers) and in disordered linear lattices (Anderson modes). Numerical studies on a class of two-dimensional systems of the Klein-Gordon type show that ...