Search results for "Linea"
showing 10 items of 7724 documents
Breather Molecular Complexes in a Passively Mode‐Locked Fiber Laser
2021
International audience; Breathing solitons are nonlinear waves in which the energy concentrates in a localized and oscillatory fashion. Similarly to stationary solitons, breathers in dissipative systems can form stable bound states displaying molecule-like dynamics, which are frequently called breather molecules. So far, the experimental observation of optical breather molecules and the real-time detection of their dynamics are limited to diatomic molecules, that is, bound states of only two breathers. In this work, the observation of different types of breather complexes in a mode-locked fiber laser: multibreather molecules, and molecular complexes originating from the binding of two breat…
Subharmonic and homoclinic bifurcations in the driven and damped sine-Gordon system
1999
Abstract Chaotic responses induced by an applied biharmonic driven signal on the sine-Gordon (sG) system influenced by a constant dc-driven and the damping fields are investigated using a collective coordinate approach for the motion of the breather in the system. For this biharmonic signal, one term has a large amplitude at low frequency. Thus, the classical Melnikov method does not apply to such a system; however, we use the modified version of the Melnikov method to homoclinic bifurcations of the perturbed sG system. Additionally resonant breathers are studied using the modified subharmonic Melnikov theory. This dynamic behavior is illustrated by some numerical computations.
Phonon calculations in cubic and tetragonal phases of SrTiO3: A comparative LCAO and plane-wave study
2011
The atomic, electronic structure and phonon frequencies have been calculated in cubic and low-temperature tetragonal SrTiO${}_{3}$ phases at the ab initio level. We demonstrate that the use of the hybrid exchange-correlation PBE0 functional gives the best agreement with experimental data. The results for the standard generalized gradient approximation (PBE) and hybrid PBE0 functionals are compared for the two types of approaches: a linear combination of atomic orbitals (CRYSTAL09 computer code) and plane waves (VASP5.2 code). The relation between cubic and tetragonal phases and the relevant antiferrodistortive phase transition is discussed in terms of group theory and is illustrated with an…
La circulation des objets métalliques à l'âge du Bronze entre Rhône et Saône: utilisation d'une transformation cartographique linéaire
2006
In order to gain a better understanding of circulation flows of metal objects during the Bronze Age, and move beyond traditional distribution maps of archaeological discoveries, the authors propose a more quantitative and concise method of graphic representation, namely cartographic linear transformation. The value of the method was tested on the Saône-Rhône axis. Bronze axes, swords and daggers were recorded along a 50 km strip either side of the river axis, in order to estimate the frequency and mass of objects in “circulation”.
Una pequeña lámina de plomo con inscripción ibérica de paleografía arcaica del Pico de los Ajos (Yátova, València)
2021
espanolEn este trabajo editamos una pequena lamina de plomo hallada en el Pico de los Ajos (Yatova) en la campana de 2018. La lamina aparecio plegada y contiene una inscripcion iberica de una sola linea en cada cara que muy probablemente configure un solo texto completo. Sus caracteristicas formales son poco comunes, siendo el paralelo mas cercano el de las laminas votivas de El Amarejo. La presencia del elemento kutuŕ, frecuente en las inscripciones votivas rupestres, tambien apuntaria a una interpretacion religiosa. Desde el punto de vista paleografico, cabe senalar que se trata de un texto explicitamente dual, ya que conviven en el las dos variantes de te y ŕ. A pesar de que el contexto …
Buckling and nonlinear dynamics of elastically coupled double-beam systems
2016
Abstract This paper deals with damped transverse vibrations of elastically coupled double-beam system under even compressive axial loading. Each beam is assumed to be elastic, extensible and supported at the ends. The related stationary problem is proved to admit both unimodal (only one eigenfunction is involved) and bimodal (two eigenfunctions are involved) buckled solutions, and their number depends on structural parameters and applied axial loads. The occurrence of a so complex structure of the steady states motivates a global analysis of the longtime dynamics. In this regard, we are able to prove the existence of a global regular attractor of solutions. When a finite set of stationary s…
A first-principles DFT study of UN bulk and (001) surface: comparative LCAO and PW calculations.
2008
LCAO and PW DFT calculations of the lattice constant, bulk modulus, cohesive energy, charge distribu- tion, band structure, and DOS for UN single crystal are analyzed. It is demonstrated that a choice of the uranium atom relativistic effective core potentials considerably affects the band structure and magnetic structure at low tem- peratures. All calculations indicate mixed metallic-covalent chemical bonding in UN crystal with U5f states near the Fermi level. On the basis of the experience accumulated in UN bulk simulations, we compare the atomic and elec- tronic structure as well as the formation energy for UN(001) surface calculated on slabs of different thickness using both DFT approach…
On the hyperporous non-linear elasticity model for fusion-relevant pebble beds
2010
Abstract Packed pebble beds are particular granular systems composed of a large amount of small particles, arranged in irregular lattices and surrounded by a gas filling interstitial spaces. Due to their heterogeneous structure, pebble beds have non-linear and strongly coupled thermal and mechanical behaviours whose constitutive models seem limited, being not suitable for fusion-relevant design-oriented applications. Within the framework of the modelling activities promoted for the lithiated ceramics and beryllium pebble beds foreseen in the Helium-Cooled Pebble Bed breeding blanket concept of DEMO, at the Department of Nuclear Engineering of the University of Palermo (DIN) a thermo-mechani…
Explicit Bézier control net of a PDE surface
2017
The PDE under study here is a general fourth-order linear elliptic Partial Differential Equation. Having prescribed the boundary control points, we provide the explicit expression of the whole control net of the associated PDE Bézier surface. In other words, we obtain the explicit expressions of the interior control points as linear combinations of free boundary control points. The set of scalar coefficients of these combinations works like a mould for PDE surfaces. Thus, once this mould has been computed for a given degree, real-time manipulation of the resulting surfaces becomes possible by modifying the prescribed information. The work was partially supported by Spanish Ministry of Econo…
Izmaiņu dispersijas novērtēšana, izmantojot Būtstrepa metodi
2018
Eiropas Savienības darbaspēka apsekojumu izmaiņu dispersijas novērtēšanai izmanto linearizāciju. Bakalaura darba mērķis ir atrast piemērotu alternatīvu metodi linearizācijai darbaspēka apsekojumu izmaiņu dispersijas novērtēšanai. Kā alternatīva tiks apskatīta būtsrtepa metode. Darbā izmantoti Eiropas Savienības Statistikas biroja Eurostat darbaspēka apsekojuma dati, kuriem tiek pielietota būtstrepa iterāciju ģenerēšana. Iterācijas tiek ģenerētas dažādiem skaitiem un analizēti iegūtie rezultāti. Zināms, ka, jo lielāks iterāciju skaits, jo precīzāk būtstreps apraksta reālos datus. Palielinot būstrepēšanas iterāciju skaitu, vēlams tuvinoties Eurostat iegūtajiem rezultātiem.