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Kharmouche A.,Ferhat Abbas University Setif
Journal of Magnetism and Magnetic Materials | Year: 2013

Series of CoxCr1-x thin films have been evaporated under vacuum onto Si (100) and glass substrates. An alternating gradient field magnetometer is used to characterize the static magnetic properties of the samples and Brillouin light scattering is used to study their dynamic magnetic properties. The in-plane easy magnetization axis is found for all samples. Using these results, we computed the first, second and uniaxial magnetic anisotropy factors by several methods. Values of the computed effective magnetic anisotropy factors higher than 106 erg cm-3 have been found. The results are discussed and correlated. © 2012 Elsevier B.V. Source


Khebbache H.,Ferhat Abbas University Setif
International Journal of Control and Automation | Year: 2012

The work proposed in this paper aims to design a robust control algorithm for the attitude tracking of a quadrotor UAV system in presence of actuator faults. The attitude dynamic modeling of quadrotor while taking into account various physical phenomena, which can influence the dynamics of a flying structure is presented. Subsequently, a control algorithm which based on robust integral backstepping taking into account the actuator faults is developed. Lyapunov based stability analysis shows that the proposed control algorithm keep the stability of the closed loop dynamics of quadrotor UAV even after the presence of actuator faults. Numerical simulation results are provided to show the good tracking performance of proposed control laws. Source


The ferromagnetic resonance intrinsic field linewidth ΔH is investigated for a multilayer system such as a coupled trilayer and a spin valve structure. The magnetic coupling between two ferromagnetic layers separated by a nonmagnetic interlayer will be described by the bilinear J1 and biquadratic J2 coupling parameters. The interaction at the interface of the first ferromagnetic layer with the antiferromagnetic one is account for by the exchange anisotropy field, HE. A general formula is derived for the intrinsic linewidth ΔH. The explicit dependence of ΔH with HE, J1 and J2 will be highlighted. Analytical expressions for each mode field linewidth are found in special cases. Equivalent damping constants will be discussed. © 2015 Author(s). Source


Maamache M.,Ferhat Abbas University Setif
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

It is well known that Hermitian operators have real eigenvalues while non-Hermitian ones may have complex eigenvalues. Recently, numerical and analytical results indicated that the spectra of many non-Hermitians Hamiltonians H are indeed real if they are invariant under the combined action of self-adjoint parity P and time reversal T. The concept of a pseudo-Hermitian operator showed that the remarkable spectral properties of the PT-symmetric Hamiltonians follow from their pseudo-Hermiticity. It is possible to explain these observations by the concept of pseudo-Hermitian operators and to formulate completeness and orthonormality relations. Most of the effort has been devoted to study time-independent non-Hermitian systems. In this paper, we study the exactly solvable time-dependent periodic pseudo-Hermitian Hamiltonians. The method introduced, to make the reality of eigenvalues and phases, is based on a Floquet decomposition of the evolution operator UH(t)=ZH(t)exp(iMHt) associated with the periodic pseudo-hermitian Hamiltonian H(t)=H(t+T). One of the results found in this paper concerns a calculation of Berry's phase for periodic, but not necessarily adiabatic, pseudo-Hermitian Hamiltonians. A two-level pseudo-Hermitian system is discussed as an illustrative example. © 2015 American Physical Society. Source


Achache M.,Ferhat Abbas University Setif
RAIRO - Operations Research | Year: 2016

In this paper, a weighted-path-following interior point algorithm for P∗(κ)-linear complementarity problems (P∗(κ)-LCP) is presented. The algorithm uses at each weighted interior point iteration only feasible full-Newton steps and the strategy of the central-path for getting a solution for P∗(κ)-LCP. We prove that the proposed algorithm has quadratically convergent with polynomial time. The complexity bound, namely, O((1+κ)√n log n/ε) of the algorithm is obtained. Few numerical tests are reported to show the efficiency of the algorithm. © EDP Sciences, ROADEF, SMAI 2016. Source

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