The Experts below are selected from a list of 99 Experts worldwide ranked by ideXlab platform
Akhlesh Lakhtakia - One of the best experts on this subject based on the ideXlab platform.
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theory of optical scattering by achiral carbon nanotubes and their potential as optical nanoantennas
Physical Review B, 2006Co-Authors: Ya G Slepyan, M V Shuba, S A Maksimenko, Akhlesh LakhtakiaAbstract:The Leontovich-Levin Equation for optical scattering by an achiral carbon nanotube (CNT) of finite length is formulated, based on a quantum-mechanical microscopic model of the conductivity. Both approximate analytical and numerical solutions of the Leontovich-Levin Equation Yield a comparable surface current density distribution and scattering pattern. Applications over a wide frequency range from the terahertz to the ultraviolet are possible. The CNT polarizability in the low-frequency range and the scattering pattern in the range of optical interband transitions as well as in the vicinity of plasmon resonance are calculated. Geometric resonances of strongly retarded surface waves emerge and can be used for the qualitative interpretation of experimentally observed features in the optical response characteristics of CNT-based composite mediums. The potential of isolated CNTs as optical nanoantennas of both the receiving and transmitting types is established.
Peter Eberhard - One of the best experts on this subject based on the ideXlab platform.
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Fuzzy arithmetical stability analysis of uncertain machining systems
Mechanical Systems and Signal Processing, 2018Co-Authors: Dominik Hamann, Nico-philipp Walz, Achim Fischer, Michael Hanss, Peter EberhardAbstract:Abstract The dynamical behavior of machining processes with parameter uncertainties is analyzed using the possibilistic approach of fuzzy arithmetic. The concept is used to simulate and analyze uncertain models of different complexity. Emphasis is put on the analysis of dynamic stability and the inclusion of the uncertain parameters therein. The stability limits, which are defined by an implicit Equation, Yield two-dimensional fuzzy-valued results, so that standard solution methods are not directly applicable. Therefore, a general method for the solution of implicit Equations is presented that may be applied to the stability analysis of arbitrary time-delayed systems. The presented method as well as a fuzzy sensitivity analysis are then applied to the stability analysis of exemplary systems. The propagation characteristic as well as the fuzzy sensitivity analysis allow to see the effect of uncertainties on the system output and quantify the effect of given uncertain parameters.
Yoshichika Otani - One of the best experts on this subject based on the ideXlab platform.
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estimation of spin diffusion length from the magnitude of spin current absorption multiterminal ferromagnetic nonferromagnetic hybrid structures
Physical Review B, 2005Co-Authors: Takashi Kimura, Jaroslav Hamrle, Yoshichika OtaniAbstract:We demonstrate the method to calculate the spatial distributions of the spin current and accumulation in the multiterminal ferromagnetic/nonmagnetic hybrid structure using an approximate electrotransmission line. The analyses based on the obtained Equation Yield the results, in good agreement with the experimental ones. This implies that the method allows us to determine the spin diffusion length of an additionally connected electrically floating wire from the reduction of the spin signal.
Ya G Slepyan - One of the best experts on this subject based on the ideXlab platform.
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theory of optical scattering by achiral carbon nanotubes and their potential as optical nanoantennas
Physical Review B, 2006Co-Authors: Ya G Slepyan, M V Shuba, S A Maksimenko, Akhlesh LakhtakiaAbstract:The Leontovich-Levin Equation for optical scattering by an achiral carbon nanotube (CNT) of finite length is formulated, based on a quantum-mechanical microscopic model of the conductivity. Both approximate analytical and numerical solutions of the Leontovich-Levin Equation Yield a comparable surface current density distribution and scattering pattern. Applications over a wide frequency range from the terahertz to the ultraviolet are possible. The CNT polarizability in the low-frequency range and the scattering pattern in the range of optical interband transitions as well as in the vicinity of plasmon resonance are calculated. Geometric resonances of strongly retarded surface waves emerge and can be used for the qualitative interpretation of experimentally observed features in the optical response characteristics of CNT-based composite mediums. The potential of isolated CNTs as optical nanoantennas of both the receiving and transmitting types is established.
Mikhail B. Sheftel - One of the best experts on this subject based on the ideXlab platform.
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partner symmetries of the complex monge ampere Equation Yield hyper kahler metrics without continuous symmetries
Journal of Physics A, 2003Co-Authors: A. A. Malykh, Yavuz Nutku, Mikhail B. SheftelAbstract:We extend the Mason–Newman Lax pair for the elliptic complex Monge–Ampere Equation so that this Equation itself emerges as an algebraic consequence. We regard the function in the extended Lax Equations as a complex potential. Their differential compatibility condition coincides with the determining Equation for the symmetries of the complex Monge–Ampere Equation. We shall identify the real and imaginary parts of the potential, which we call partner symmetries, with the translational and dilatational symmetry characteristics, respectively. Then we choose the dilatational symmetry characteristic as the new unknown replacing the Kahler potential. This directly leads to a Legendre transformation. Studying the integrability conditions of the Legendre-transformed system we arrive at a set of linear Equations satisfied by a single real potential. This enables us to construct non-invariant solutions of the Legendre transform of the complex Monge–Ampere Equation. Using these solutions we obtained explicit Legendre-transformed hyper-Kahler metrics with a anti-self-dual Riemann curvature 2-form that admit no Killing vectors. They satisfy the Einstein field Equations with Euclidean signature. We give the detailed derivation of the solution announced earlier and present a new solution with an added parameter. We compare our method of partner symmetries for finding non-invariant solutions to that of Dunajski and Mason who use 'hidden' symmetries for the same purpose.
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Partner symmetries of the complex Monge-Ampere Equation Yield hyper-Kahler metrics without continuous symmetries
Journal of Physics A: Mathematical and General, 2003Co-Authors: A. A. Malykh, Yavuz Nutku, Mikhail B. SheftelAbstract:We extend the Mason-Newman Lax pair for the elliptic complex Monge-Amp\`ere Equation so that this Equation itself emerges as an algebraic consequence. We regard the function in the extended Lax Equations as a complex potential. We identify the real and imaginary parts of the potential, which we call partner symmetries, with the translational and dilatational symmetry characteristics respectively. Then we choose the dilatational symmetry characteristic as the new unknown replacing the K\"ahler potential which directly leads to a Legendre transformation and to a set of linear Equations satisfied by a single real potential. This enables us to construct non-invariant solutions of the Legendre transform of the complex Monge-Amp\`ere Equation and obtain hyper-K\"ahler metrics with anti-self-dual Riemann curvature 2-form that admit no Killing vectors.