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Boqiang Huang - One of the best experts on this subject based on the ideXlab platform.
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a revisit of the unique Polar representation of the vector valued hyperanalytic signal
European Signal Processing Conference, 2015Co-Authors: Boqiang HuangAbstract:In this paper, we extend the classic analytic signal to the Vector-valued Hyperanalytic Signal (VHaS) that is denoted to distinguish from the multivariate hypercomplex data. The 2d-Dimensional (2d-D) VHaS, S(t) : [0,1] → C 2d , is defined by a complexification of two d-D Vector-valued Hypercomplex Signals (VHcS), S(t) := G(t)e 0 + HC2d ed [G](t) e d , where HC2d ed and e i represent the Hilbert transForm and the i th unit axis, and G(t) ∊ C d , e i G C 2d . Inspired by the unique Polar Form of a classic analytic signal and the one of a 4-D VHaS proposed in [1], we provide a theoretical explanation of the unique Polar representation of a 6-D or 8-D VHaS by replacing the quaternion with octonion, which further implies the possible extension for d-D VHaS with d> 8. Moreover, the derived continuous VHcS envelope and phase from the Polar Form lead to a unified definition of the time-frequency-amplitude spectrum of the given VHcS G(t).
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a unique Polar representation of the hyperanalytic signal
International Conference on Acoustics Speech and Signal Processing, 2014Co-Authors: Boqiang Huang, Angela KunothAbstract:The hyperanalytic signal is the straight forward generalization of the classical analytic signal. It is defined by a complexification of two canonical complex signals, which can be considered as an inverse operation of the Cayley-Dickson Form of the quaternion. Inspired by the Polar Form of an analytic signal where the real instantaneous envelope and phase can be determined, this paper presents a novel method to generate a Polar representation of the hyperanalytic signal, in which the continuously complex envelope and phase can be uniquely defined. Comparing to other existing methods, the proposed Polar representation does not have sign ambiguity between the envelope and the phase, which makes the definition of the instantaneous complex frequency possible.
Angela Kunoth - One of the best experts on this subject based on the ideXlab platform.
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a unique Polar representation of the hyperanalytic signal
International Conference on Acoustics Speech and Signal Processing, 2014Co-Authors: Boqiang Huang, Angela KunothAbstract:The hyperanalytic signal is the straight forward generalization of the classical analytic signal. It is defined by a complexification of two canonical complex signals, which can be considered as an inverse operation of the Cayley-Dickson Form of the quaternion. Inspired by the Polar Form of an analytic signal where the real instantaneous envelope and phase can be determined, this paper presents a novel method to generate a Polar representation of the hyperanalytic signal, in which the continuously complex envelope and phase can be uniquely defined. Comparing to other existing methods, the proposed Polar representation does not have sign ambiguity between the envelope and the phase, which makes the definition of the instantaneous complex frequency possible.
Frederic Dumur - One of the best experts on this subject based on the ideXlab platform.
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Push-Pull Chromophores Based on the Naphthalene Scaffold: Potential Candidates for Optoelectronic Applications
Materials, 2019Co-Authors: Corentin Pigot, Malek Nechab, Guillaume Noirbent, Thanh-tuan Bui, Sebastien Peralta, Didier Gigmes, Frederic DumurAbstract:A series of ten push-pull chromophores comprising 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as the electron-withdrawing group have been designed, synthesized, and characterized by UV-visible absorption and fluorescence spectroscopy, cyclic voltammetry and theoretical calculations. The solvatochromic behavior of the different dyes has been examined in 23 solvents and a positive solvatochromism has been found for all dyes using the Kamlet-Taft solvatochromic relationship, demonstrating the Polar Form to be stabilized in Polar solvents. To establish the interest of this polyaromatic electron acceptor only synthesizable in a multistep procedure, a comparison with the analog series based on the benchmark indane-1,3-dione (1H-indene-1,3(2H)-dione) has been done. A significant red-shift of the intramolecular charge transfer band has been found for all dyes, at a comparable electron-donating group. Parallel to the examination of the photophysical properties of the different chromophores, a major improvement of the synthetic procedure giving access to 1H-cyclopenta[b]naphthalene-1,3(2H)-dione has been achieved.
Aurelien Barrau - One of the best experts on this subject based on the ideXlab platform.
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non trivial effects of sourceless forces for spinors toward an aharonov bohm gravitational effect
European Physical Journal C, 2019Co-Authors: Luca Fabbri, Flora Moulin, Aurelien BarrauAbstract:Spinor fields are written in Polar Form so as to compute their tensorial connection, an object that contains the same inFormation of the connection but which is also proven to be a real tensor. From this, one can still compute the Riemann curvature, encoding the inFormation about gravity. But even in absence of gravity, when the Riemann curvature vanishes, it may still be possible that the tensorial connection remains different from zero, and thih can have effects on matter. This is shown with examples in the two known integrable cases: the hydrogen atom and the harmonic oscillator. The fact that a spinor can feel effects due to sourceless actions is already known in electrodynamics as the Aharonov–Bohm phenomenon. A parallel between the electrodynamics case and the situation encountered here will be drawn. Some ideas about relativistic effects and their role for general treatments of quantum field theories are also underlined.
Corentin Pigot - One of the best experts on this subject based on the ideXlab platform.
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Push-Pull Chromophores Based on the Naphthalene Scaffold: Potential Candidates for Optoelectronic Applications
Materials, 2019Co-Authors: Corentin Pigot, Malek Nechab, Guillaume Noirbent, Thanh-tuan Bui, Sebastien Peralta, Didier Gigmes, Frederic DumurAbstract:A series of ten push-pull chromophores comprising 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as the electron-withdrawing group have been designed, synthesized, and characterized by UV-visible absorption and fluorescence spectroscopy, cyclic voltammetry and theoretical calculations. The solvatochromic behavior of the different dyes has been examined in 23 solvents and a positive solvatochromism has been found for all dyes using the Kamlet-Taft solvatochromic relationship, demonstrating the Polar Form to be stabilized in Polar solvents. To establish the interest of this polyaromatic electron acceptor only synthesizable in a multistep procedure, a comparison with the analog series based on the benchmark indane-1,3-dione (1H-indene-1,3(2H)-dione) has been done. A significant red-shift of the intramolecular charge transfer band has been found for all dyes, at a comparable electron-donating group. Parallel to the examination of the photophysical properties of the different chromophores, a major improvement of the synthetic procedure giving access to 1H-cyclopenta[b]naphthalene-1,3(2H)-dione has been achieved.