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International Review
of PHYSICS - Papers
Abstract
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This work is based on a numerical study of particle transport and
diffusion using ITER parameters. In particular the effects of
introducing a non monotonic safety factor (NMSF) in the case of a
reversed magnetic shear are shown. These results are compared to the
ones found by using a monotonic safety factor (MSF). Double internal
transport barriers are detected influencing the transport and diffusion
of particles. The profiles of temperature, density, radial electric
field and magnetic shear rate are computed for the case of NMSF. The
choice of the mode (m, n) and the m/n values play a dominant role for
the particle diffusion, which lead to improve the magnetic confinement.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Plasma Confinement, Tokomak, Anomalous Transport, Reversed
Magnetic Shear, Transport Barriers, Particles Diffusion, Safety Factor.
Abstract
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We study the beam-plasma heating due to the electron beam under the effect
of an external static magnetic field and semi-bounded collisional warm
plasma. The amount of energy absorbed by the plasma is obtained.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Plasma Heating, Anisotropic Plasma, Plasma Warmness.
Abstract
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Spin involved in gravitational interaction can give
rise to intriguing effects that can offer deep insights into some
aspects of the nature and essential features of gravity. The effects
caused by spin in three gravity theories (i.e., the Riemannian
torsionless gravitation, the Weitzenböck-spacetime teleparallel
gravitation, and the spin-connection Yang-Mills type gravitation) are
suggested and addressed: i) We suggest a non-Abelian gauge structure of
spin-gravity coupling in a spin-triplet Cooper-pair superconducting
background, and show that an analogue of the electroweak structure of
the standard particle physics model can be recovered; ii) The
traditional Hilbert-Einstein Lagrangian density for Einstein's
curvature-only gravitational field equation can be reformulated in terms
of contortion (or torsion) within the framework of pure-torsion gravity.
However, the evolution of a test particle spin in teleparallel
gravitation is different from that in the Riemannian torsionless
gravitation of Einstein, and this can enable us to discriminate the
curvature-only gravitation from the torsion-only gravitation by
detecting the extra spin evolutions (precession and nutation) that is
caused by the spin-torsion coupling; iii) A concept of generalized
``spin'' current density tensor of a scalar matter field is defined. The
evolution of such a generalized ``spin'' current density in a
spin-affine connection (Lorentz connection) gauge field is equivalent to
the motion of energy-momentum tensor of the scalar matter field in a
metric field. This can provide us with an insight into constructing a
Yang-Mills type spin-connection gravitational gauge theory, in which the
gravitational Lagrangian is quadratic in curvature, and the
gravitational field equation of Einstein can be recovered as a first
integral of the spin-connection gravitational gauge field equation.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Spin-gravity coupling; spin gauge field; spin-triplet
superconducting electrons, torsion-only gravity, spin evolution,
spin-connection gauge field.
 Generation
of Plasmonic Surface Optical Lattices
by S. Al-Awfi, M. S.
Bawa’aneh
Abstract - A novel
scheme of optical lattices based on effective localized surface
plasmonic modes is shown. In particular, when a metallic sheet in the
form an infinitesimally thin film deposited on a planar dielectric
substrate to created surface plasmonic modes due to an evanescent of
Hermite-Gaussian (H-G) light. The characteristic property of such a mode
is the exponential decay with distance in the vacuum region and can
basically be provided a two-dimensional optical lattices with desirable
enhancement. Such lattices can be controllable by changing the incident
angle and the order of H-G light.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Optical Lattices, Metallic Sheet, Plasmonic Surface Modes.
Dimensioning
of n+ and p+ Regions for Interdigitated Rear Contact Silicon Solar Cells
by W. Kazi-Tani, A.
Zerga, B. Benyoucef
Abstract - In this
article, we investigate the optimal design of interdigitated rear
contact silicon solar cells by using a 2D numerical simulation based on
Silvaco software. The most relevant physical and technological
parameters for the conversion efficiency are determined. Such as
substrate thickness, doping levels of different regions, width and depth
of n+ and p+ regions, space inter-regions and diffusion length (minority
carrier lifetime). The obtained results show that this structure
requires a high quality silicon substrate. Optimization of the geometry
of the n+ (emitter) and p+ (back surface field) regions confirmed that
the ratio of the widths of n+ and p+ regions should not be less than 10
to reach a high conversion efficiency. This important result allowed us
to obtain 15.21% efficiency by using a photovoltaic structure compatible
with conventional technologies.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Silicon Crystalline, Interdigitated Rear Contact, Solar Cells, 2d
Numerical Simulation.
Abstract
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The main objective of our work is to focus on the A2 binary representation
and its use for redundant arithmetic applications. The area and delay
performances of redundant binary full adder cells in different CMOS
logic styles are also investigated. In this paper, a highly
time-efficient CMOS standard cell based adding/subtracting unit using
the arithmetic A2 redundant binary representation is presented. This
structure is very suitable for implementation in VLSI of simple
mixed-signal arithmetic circuits. This unit is based on the carry-save
(CS) adding scheme with only one output stage of trans-coding. To
overcome the switching delay problem at high speed, the output stage has
been also improved. Comparisons with other works using the carry select
adding (CSA) scheme or the carry look ahead adding scheme (CLA) show
that the proposed structure offers a significant gain in speed. It was
also proved that using such technique might be also area efficient, for
enough large operands, especially when it is compared to the CLA adding
scheme.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Computer Arithmetic, A2 Redundant Binary Representation,
Carry-Save Representation, Carry-Select and Carry Look Ahead Adder.
Abstract
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The present work, constituted a theoretical study of the phenomenon of the
electric conductivity of composite conducting polymers. Generally, the
polymers are used as electrical insulators. The incorporation of
conducting loads in an insulating polymeric matrix makes it possible to
obtain materials having at the same time a high electric conductivity
and a low density[1]. These materials offer a great number of
applications such as the electromagnetic shielding, the protection of
metals against corrosion, the adhesives conducting, the connectors, the
sensors, etc. The prediction and modelling of the electrical behaviour
of these composite materials are needed for the choice of their scope
and could therefore reduce the onerous experimental work and the cost of
production through an optimized design.
We carried out a theoretical study. To make a this study, we are based
on experimental results existing in the specialized literature and we
build a new ideal model which describes the variation of electrical
conductivity in function the voluminal fraction of the conducting loads.
The comparison between our ideal model suggested and other models of
McLachlan, Kirkpatrick and Landauer, shows that the model suggested is
in concord with the experimental results.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Polymer, Conducting Polymer Composites, Matrix, Filler, Electric
Conductivity, Percolation Threshold, Mclachlan Model, Kirkpatrick Model,
Landauer Model.
Abstract
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The interaction between dimethylformamide-water soluble fluorescent sensor
of pyropheophorbide-a Me ester (PMeE) with Cu2+ metal ion was
investigated by steady-state fluorescence and uv/visible absorption
spectroscopy. The results revealed that Cu2+ metal ion caused the
fluorescence quenching of PME through a procedure of static and dynamic
quenching with fluorescent ‘‘on-off’’ type switching property. The
binding site number n, and apparent binding constant kA at different
temperatures were calculated. The interaction of Cu2+ with PMeE forms a
1:2 complex at temperatures of 291, 299, and 313 K. The fluorescence
quenching was partially reversible upon addition of EDTA disodium. The
effect of Hg2+, K+, Mg2+, Cd2+, Sn2+, Cr2+, Pb3+, Cs+, Ni2+, Ba2+, Ca2+,
Co2+, Na+, Sr2+, Mn2+, Ag+, Zn2+, Cu2+, and Fe2+ on the binding between
PME and Cu2+were studied. Our investigations provide strong evidence
that a photosensitizer in a addition to the reactive oxygen species that
generates for tumor destruction, it could be able also to target tumor
in a copper-dependent manner.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Fluorescence, Tumor Angiogenesis, Binding Interaction, Static and
Dynamic Quenching, Electronic Absorption.
Abstract
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In this article, we construct the exact traveling wave solutions of the
combined KdV-Burgers equation with variable coefficients using two
different methods via the generalized (G’/G)-expansion method and the
Exp-function method which play an important role in mathematical
physics. As a result, hyperbolic, trigonometric and rational function
solutions with parameters are obtained. When these parameters are taken
special values, the solitary wave solutions are derived from the
hyperbolic function solution. It is shown that the proposed two methods
are direct, effective and can be applied to many other nonlinear
evolution equations in mathematical physics.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Nonlinear PDEs, Generalized (G’/G)-Expansion Method, Combined KdV-Burgers
Equation, Exp-Function Method, Exact Solutions.
Abstract
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Emissions of Nitrogen monoxide from soils and isoprene from vegetation
are evaluated to complete the cadastre emission established for Côte
d'Ivoire, where pyrogenic, domestic and industrial sources were
considered. The biogenic emissions are estimated for each season (dry
and wet). They take into account the heterogeneity of vegetation cover
and seasonal variation. The estimated NO fluxes ranged from 4.32 10-5
g m-2 d-1 for the dry season without fires 1.73
10-4 g m-2 d-1
for the wet season in the Sahelian and Sudanese savannas, 1.04 10-4
g m-2 d-1 (dry season without fires) to 3.46 10-4
g m-2 d-1 (wet season) in the Guinean savanna
and 3.46 10-4 g m-2
d-1 (season dry without fires) to 4.32 10-4
g m-2 d-1 (wet season) in the forest. We have
respectively for the dry season and wet season 8.7 10-4
g C m-2 d-1 and 0.03 g C m-2 d-1
of isoprene emitted by savanna Sahelian and Sudanese, 2.6 10-3
g C m-2 d-1 and 0.09 g C m-2 d-1
of isoprene emitted by the Guinean savanna, 5.2 10-3
g C m-2 d-1 and 0.09 g C m-2 d-1
of isoprene issued by the forest. The biogenic emissions show a decrease
between North and South of Côte d'Ivoire. In the presence of fires, NO
emissions can triple.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Biogenic emissions, nitric oxide, isoprene, Côte d’Ivoire, West
Africa.
Abstract
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This article is a first approach to the use of the moiré for assessing
displacements and deformations, one using the indexing of the fringes
i.e. their classifications. The complexity of the interference fringe
patterns motivated the parallel development of companion numerical
models for simulating Moiré patterns response for known boundary
conditions. The mathematical solutions of moiré patterns are, in many
cases, identical with those arising in physical problems. Examples are
given for a number of phenomena arising in physical optics,
hydrodynamics, and electrostatics. The feasibility and effectiveness of
the proposed method is demonstrated by computer simulation.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Gratings, Images, Simulation, Topography.
Abstract
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The carrier’s dynamic in a HEMT structure is studied using quasi
two-dimensional model which is based on the conservation equations of
energy and moment, which are derived from Boltzmann’s transport
equation. The simulation has allowed us to extract physical quantities
that characterize the dynamic of carriers in addition to the evolution
of the basic elements of the equivalent schema in small signal.
Copyright © 2010 Praise Worthy Prize S.r.l. -
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Keywords:
Heterostructure, nanodevice, quantum well, dynamic transport,
HEMT.
Abstract
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Polymer/liquid crystal (PDLC) films were prepared using ultraviolet
radiation by a polymerization induced phase separation process. The
composite material was obtained from a blend including a
polypropyleneglycoldiacrylate and the nematic liquid crystal mixture E7.
A Polymerisation Induced Phase Separation (PIPS) occurs during
polymerization/crosslinking and this process was monitored by Fourier
Transform Infrared (FTIR) spectroscopy. The electro-optical properties
of the polymer/LC films were investigated as a function of film
thickness and sample composition. The obtained transmission versus
voltage curves exhibit a good reproducibility, highly scattering
off-states, and a high transmission in the on-state.
Copyright © 2010 Praise Worthy Prize S.r.l. -
All rights reserved
Keywords:
Liquid Crystals, Polymer Networks, UV-curing, Infrared
Spectroscopy, Electro-Optical analysis.
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