10,524 research outputs found
Universal R-C crossover in current-voltage characteristics for unshunted array of overdamped Nb-AlO_x-Nb Josephson junctions
We report on some unusual behavior of the measured current-voltage
characteristics (CVC) in artificially prepared two-dimensional unshunted array
of overdamped Nb-AlO_x-Nb Josephson junctions. The obtained nonlinear CVC are
found to exhibit a pronounced (and practically temperature independent)
crossover at some current I_{cr}=\left(\frac{1}{2\beta_C}-1\right)I_C from a
resistance R dominated state with V_R=R\sqrt{I^2-I_C^2} below I_{cr} to a
capacitance C dominated state with V_C=\sqrt{\frac{\hbar}{4eC}} \sqrt{I-I_C}
above I_{cr}. The origin of the observed behavior is discussed within a
single-plaquette approximation assuming the conventional RSJ model with a
finite capacitance and the Ambegaokar-Baratoff relation for the critical
current of the single junction
Manifestation of geometric resonance in current dependence of AC susceptibility for unshunted array of Nb-AlOx-Nb Josephson junctions
A pronounced resonance-like structure has been observed in the current
dependence of AC susceptibility for two-dimensional array of unshunted
Nb-AlOx-Nb Josephson junctions. Using a single-plaquette approximation, we were
able to successfully fit our data assuming that resonance structure is related
to the geometric (inductive) properties of the array.Comment: to appear in Physica C (in press
On the optimum distribution of enzyme feed in a cascade of CSTR's performing an enzyme-catalyzed reaction with deactivation
A search for the optimum fractional distribution of an enzyme-rich stream to the various reactors of a cascade of CSTR's was implemented. A theoretical analysis, laid out in dimensionless form and based on the assumptions that the system is operated under steady state conditions, the enzyme undergoes first order deactivation, and the reaction catalyzed by the enzyme follows Michaelis-Menten kinetics, is reported. The objective function utilised is the minimisation of the overall volume of the cascade, and analytical expressions are obtained for the concentration of active enzyme and substrate in the outlet stream from each reactor. It is found that the best option is to add the whole enzyme-rich stream to the first reactor in the cascade irrespective of the operating and kinetic parameters of the system
Semiclassical back reaction around a cosmic dislocation
The energy-momentum vacuum average of a conformally coupled massless scalar
field vibrating around a cosmic dislocation (a cosmic string with a dislocation
along its axis) is taken as source of the linearized semiclassical Einstein
equations. The solution up to first order in the Planck constant is derived.
Motion of a test particle is then discussed, showing that under certain
circumstances a helical-like dragging effect, with no classical analogue around
the cosmic dislocation, is induced by back reaction.Comment: Published version, 4 pages, no figures, REVTeX4 fil
Aplicação de abamectina como alternativa de controle químico do nematoide-das-galhas em melão.
O objetivo do trabalho foi avaliar o efeito da abamectina na redução populacional de M. incognita, na cultura do melão
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