The Experts below are selected from a list of 12087 Experts worldwide ranked by ideXlab platform
G Uehara - One of the best experts on this subject based on the ideXlab platform.
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algebraic reconstruction combined with the signal space separation method for the inverse magnetoencephalography problem with a dipole Quadrupole Source
Journal of Applied Physics, 2014Co-Authors: T Nara, K Koiwa, S Takagi, D Oyama, G UeharaAbstract:This paper presents an algebraic reconstruction method for dipole-Quadrupole Sources using magnetoencephalography data. Compared to the conventional methods with the equivalent current dipoles Source model, our method can more accurately reconstruct two close, oppositely directed Sources. Numerical simulations show that two Sources on both sides of the longitudinal fissure of cerebrum are stably estimated. The method is verified using a quadrupolar Source phantom, which is composed of two isosceles-triangle-coils with parallel bases.
A. Mascio - One of the best experts on this subject based on the ideXlab platform.
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Ship underwater noise assessment by the acoustic analogy. Part I: nonlinear analysis of a marine propeller in a uniform flow
Journal of Marine Science and Technology, 2013Co-Authors: S. Ianniello, R. Muscari, A. MascioAbstract:The aim of this work is to analyze the hydroacoustic behavior of a marine propeller through the acoustic analogy and to test the versatility and effectiveness of this approach in dealing with the many (and relatively unexplored) issues concerning the underwater noise and its numerical prediction. In particular, a propeller in a noncavitating open water condition is examined here by coupling a Reynolds averaged Navier–Stokes hydrodynamic solver to a hydroacoustic code implementing different resolution forms of the Ffowcs Williams–Hawkings (FWH) equation. The numerical results suggest that unlike the analogous aeronautical problem, where the role played by the nonlinear Quadrupole Sources is known to be relevant just at high transonic or supersonic regime, the pressure field underwater seems to be significantly affected by the flow nonlinearities, while the contribution from the linear terms (the thickness and loading noise components) is dominant only in a spatially very limited region. Then, contrary to popular belief and regardless of the low blade rotational speed, a reliable hydroacoustic analysis of a marine propeller cannot put aside the contribution of the nonlinear noise Sources represented by the turbulence and vorticity three-dimensional fields and requires the computation of the FWH Quadrupole Source terms.
T Nara - One of the best experts on this subject based on the ideXlab platform.
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algebraic reconstruction combined with the signal space separation method for the inverse magnetoencephalography problem with a dipole Quadrupole Source
Journal of Applied Physics, 2014Co-Authors: T Nara, K Koiwa, S Takagi, D Oyama, G UeharaAbstract:This paper presents an algebraic reconstruction method for dipole-Quadrupole Sources using magnetoencephalography data. Compared to the conventional methods with the equivalent current dipoles Source model, our method can more accurately reconstruct two close, oppositely directed Sources. Numerical simulations show that two Sources on both sides of the longitudinal fissure of cerebrum are stably estimated. The method is verified using a quadrupolar Source phantom, which is composed of two isosceles-triangle-coils with parallel bases.
Andrey B Evlyukhin - One of the best experts on this subject based on the ideXlab platform.
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analytical model of resonant electromagnetic dipole Quadrupole coupling in nanoparticle arrays
Physical Review B, 2019Co-Authors: Viktoriia E Babicheva, Andrey B EvlyukhinAbstract:An analytical model for investigations of multipole coupling effects in the finite and infinite nanoparticle arrays supporting electromagnetic resonances is presented and discussed. This model considers the contributions of both electric and magnetic modes excited in the nanoparticles, including electric and magnetic dipoles and electric and magnetic Quadrupoles. The magnetic Quadrupole propagator (Green's tensor) that describes the electromagnetic field generated by a point magnetic Quadrupole Source in all wave zones is derived. As an example, we apply the developed model to study infinite two-dimensional rectangular periodic arrays of spherical silicon nanoparticles supporting the dipole and Quadrupole resonant responses. The correctness and accuracy of the analytical model are confirmed by the agreement of its results with the results of full-wave numerical simulations. Using the developed model, we show the electromagnetic coupling between electric dipole and magnetic Quadrupole moments as well as between magnetic dipole and electric Quadrupole moments even for the case of an infinite rectangular periodic array of spherical nanoparticles. The strong suppression of the dipole or Quadrupole moment due to the coupling effects is demonstrated and discussed for spherical nanoparticle arrays. The analytical expressions for the reflection and transmission coefficients written with the effective dipole and Quadrupole polarizabilities are derived for normal light incidences and zero-order diffraction. The derived expressions are applied to explain the lattice anapole (invisibility) states when the incident light is transmitted unperturbed through the silicon nanoparticle array. The important role of dipole and Quadrupole excitations in scattering compensation resulting in the lattice anapole effect is explicitly demonstrated. The presented approach can be used for designing metasurfaces and further utilizing them in developing ultrathin functional optical elements.
S. Ianniello - One of the best experts on this subject based on the ideXlab platform.
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Ship underwater noise assessment by the acoustic analogy. Part I: nonlinear analysis of a marine propeller in a uniform flow
Journal of Marine Science and Technology, 2013Co-Authors: S. Ianniello, R. Muscari, A. MascioAbstract:The aim of this work is to analyze the hydroacoustic behavior of a marine propeller through the acoustic analogy and to test the versatility and effectiveness of this approach in dealing with the many (and relatively unexplored) issues concerning the underwater noise and its numerical prediction. In particular, a propeller in a noncavitating open water condition is examined here by coupling a Reynolds averaged Navier–Stokes hydrodynamic solver to a hydroacoustic code implementing different resolution forms of the Ffowcs Williams–Hawkings (FWH) equation. The numerical results suggest that unlike the analogous aeronautical problem, where the role played by the nonlinear Quadrupole Sources is known to be relevant just at high transonic or supersonic regime, the pressure field underwater seems to be significantly affected by the flow nonlinearities, while the contribution from the linear terms (the thickness and loading noise components) is dominant only in a spatially very limited region. Then, contrary to popular belief and regardless of the low blade rotational speed, a reliable hydroacoustic analysis of a marine propeller cannot put aside the contribution of the nonlinear noise Sources represented by the turbulence and vorticity three-dimensional fields and requires the computation of the FWH Quadrupole Source terms.
