20,197 research outputs found
A Model for Quantum Stochastic Absorption in Absorbing Disordered Media
Wave propagation in coherently absorbing disordered media is generally
modeled by adding a complex part to the real part of the potential. In such a
case, it is already understood that the complex potential plays a duel role; it
acts as an absorber as well as a reflector due to the mismatch of the phase of
the real and complex parts of the potential. Although this model gives expected
results for weakly absorbing disordered media, it gives unphysical results for
the strong absorption regime where it causes the system to behave like a
perfect reflector. To overcome this issue, we develop a model here using
stochastic absorption for the modeling of absorption by "fake", or "side",
channels obviating the need for a complex potential. This model of stochastic
absorption eliminates the reflection that is coupled with the absorption in the
complex potential model and absorption is proportional to the magnitude of the
absorbing parameter. Solving the statistics of the reflection coefficient and
its phase for both the models, we argue that stochastic absorption is a
potentially better way of modeling absorbing disordered media.Comment: 5 pages, 4 figure
In vitro antimicrobial and antioxidant activities of the essential oil of Craniotome furcata
The aim of present study was, to investigate the essential oil of Craniotome furcata for its antimicrobial and antioxidant activities. The essential oil was obtained by steam distillation of the flowering aerial parts of C. furcata. The oil was tested for its antimicrobial activity in vitro against four Gram-positive, four Gram-negative bacteria and three fungi, by using disk diffusion and tube dilution methods. The antioxidant potential of the essential oil was investigated by two different models DPPH free radical and ABTS free radical cation scavenging. The essential oil was effective against all the tested microorganisms, with minimum inhibitory concentrations (MICs) ranged from 4.11±1.44 to 0.30±0.10 mg/ml. The oil showed antioxidant activity in DPPH free radical and ABTS free radical cation scavenging model. The results of this study revealed that the essential oil of C. furcata possesses antimicrobial and antioxidant activities
An improved magnetic field simulator - MAGFLD.
An improved two-dimensional simulator MAGFLD has been developed which is useful for the design and simulation of periodic permanent magnet (PPM) focusing system for linear beam tubes. At present, input is possible only through the input file, which is very simple and user friendly. A complete PPM circuit is generated using the coordinates of first pole piece, first magnet, gun adapter (if the structure is a-periodic) and the region of computation. Small mesh units of either square or rectangular shapes can be used with mesh refinement capability in one or more regions in any or both directions for better accuracy of the solution. Materials with different magnetic permeability can be modeled by defining a characteristic value for each mesh point of the geometry. The effective potential value at each point in the region of interest is calculated based on the vector potential model by using the 5-point finite difference method and the solution is achieved by over relaxation technique for faster convergence. This package has an interface with EGUN to model the electron gun and collector under the influence of magnetic field. Versatile color graphics are capable of plotting both axial magnetic field and flux lines along with the magnetic circuit. MAGFLD has been validated against some published data and experimental results
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