Relevant bibliographies by topics / Approximation du potentiel

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  2. Dissertations / Theses
  3. Books
  4. Book chapters
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Academic literature on the topic 'Approximation du potentiel'

Author: Grafiati
Published: 4 June 2021
Last updated: 11 February 2022

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Journal articles on the topic "Approximation du potentiel"

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Koumantiga, Dabitora. "Ecotourisme et aires protégées: L’histoire, un potentiel latent pour le complexe OKM (Togo, Afrique)." PASOS. Revista de Turismo y Patrimonio Cultural 19, no. 2 (2021): 223–38. http://dx.doi.org/10.25145/j.pasos.2021.19.015.

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In Mexico, there are 194 archaeological zones open to the public under the custody of the National Institute for Anthropology and History. However, there are also many other sites that operate outside the federal management model and the current legal framework. These are called “limbos” here and are clas‑ sified by who administers them and the land ownership regime. Through the review of three cases spread over Mexico, a first approximation of their key problems and shared dynamics is offered that factors in legal, bureaucratic and socioeconomic aspects that underlie the unauthorized use of archaeological heritage. It is concluded that they are “in limbo “mainly due to ambiguities in the legislation and loopholes that have been exploited by stakeholders to allow them to use of these ruins as a tourist attraction.
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Payne, Joshua L., and Margaret J. Eppstein. "Pair Approximations of Takeover Dynamics in Regular Population Structures." Evolutionary Computation 17, no. 2 (June 2009): 203–29. http://dx.doi.org/10.1162/evco.2009.17.2.203.

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In complex adaptive systems, the topological properties of the interaction network are strong governing influences on the rate of flow of information throughout the system. For example, in epidemiological models, the structure of the underlying contact network has a pronounced impact on the rate of spread of infectious disease throughout a population. Similarly, in evolutionary systems, the topology of potential mating interactions (i.e., population structure) affects the rate of flow of genetic information and therefore affects selective pressure. One commonly employed method for quantifying selective pressure in evolutionary algorithms is through the analysis of the dynamics with which a single favorable mutation spreads throughout the population (a.k.a. takeover time analysis). While models of takeover dynamics have been previously derived for several specific regular population structures, these models lack generality. In contrast, so-called pair approximations have been touted as a general technique for rapidly approximating the flow of information in spatially structured populations with a constant (or nearly constant) degree of nodal connectivities, such as in epidemiological and ecological studies. In this work, we reformulate takeover time analysis in terms of the well-known Susceptible-Infectious-Susceptible model of disease spread and adapt the pair approximation for takeover dynamics. Our results show that the pair approximation, as originally formulated, is insufficient for approximating pre-equibilibrium dynamics, since it does not properly account for the interaction between the size and shape of the local neighborhood and the population size. After parameterizing the pair approximation to account for these influences, we demonstrate that the resulting pair approximation can serve as a general and rapid approximator for takeover dynamics on a variety of spatially-explicit regular interaction topologies with varying population sizes and varying uptake and reversion probabilities. Strengths, limitations, and potential applications of the pair approximation to evolutionary computation are discussed.
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Makhlaichuk, P. V., M. P. Malomuzh, and I. V. Zhyganiuk. "Potential in the Multipole Approximation." Ukrainian Journal of Physics 58, no. 3 (March 2013): 278–88. http://dx.doi.org/10.15407/ujpe58.03.0278.

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Hao, Qi, and Alexey Stovas. "Analytic calculation of phase and group velocities of P-waves in orthorhombic media." GEOPHYSICS 81, no. 3 (May 2016): C79—C97. http://dx.doi.org/10.1190/geo2015-0156.1.

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We have developed an approximate method to calculate the P-wave phase and group velocities for orthorhombic media. Two forms of analytic approximations for P-wave velocities in orthorhombic media were built by analogy with the five-parameter moveout approximation and the four-parameter velocity approximation for transversely isotropic media, respectively. They are called the generalized moveout approximation (GMA)-type approximation and the Fomel approximation, respectively. We have developed approximations for elastic and acoustic orthorhombic media. We have characterized the elastic orthorhombic media in Voigt notation, and we can describe the acoustic orthorhombic media by introducing the modified Alkhalifah’s notation. Our numerical evaluations indicate that the GMA-type and Fomel approximations are accurate for elastic and acoustic orthorhombic media with strong anisotropy, and the GMA-type approximation is comparable with the approximation recently proposed by Sripanich and Fomel. Potential applications of the proposed approximations include forward modeling and migration based on the dispersion relation and the forward traveltime calculation for seismic tomography.
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DELLAR, PAUL J. "Variations on a beta-plane: derivation of non-traditional beta-plane equations from Hamilton's principle on a sphere." Journal of Fluid Mechanics 674 (March 14, 2011): 174–95. http://dx.doi.org/10.1017/s0022112010006464.

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Starting from Hamilton's principle on a rotating sphere, we derive a series of successively more accurate β-plane approximations. These are Cartesian approximations to motion in spherical geometry that capture the change with latitude of the angle between the rotation vector and the local vertical. Being derived using Hamilton's principle, the different β-plane approximations each conserve energy, angular momentum and potential vorticity. They differ in their treatments of the locally horizontal component of the rotation vector, the component that is usually neglected under the traditional approximation. In particular, we derive an extended set of β-plane equations in which the locally vertical and locally horizontal components of the rotation vector both vary linearly with latitude. This was previously thought to violate conservation of angular momentum and potential vorticity. We show that the difficulty in maintaining these conservation laws arises from the need to express the rotation vector as the curl of a vector potential while approximating the true spherical metric by a flat Cartesian metric. Finally, we derive depth-averaged equations on our extended β-plane with topography, and show that they coincide with the extended non-traditional shallow-water equations previously derived in Cartesian geometry.
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STOJANOVIĆ, MIRJANA. "PERTURBED SCHRÖDINGER EQUATION WITH SINGULAR POTENTIAL AND INITIAL DATA." Communications in Contemporary Mathematics 08, no. 04 (August 2006): 433–52. http://dx.doi.org/10.1142/s0219199706002180.

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We consider linear Schrödinger equation perturbed by delta distribution with singular potential and the initial data. Due to the singularities appearing in the equation, we introduce two kinds of approximations: the parameter's approximation for potential and the initial data given by mollifiers of different growth and the approximation for the Green function for Schrödinger equation with regularized derivatives. These approximations reduce the perturbed Schrödinger equation to the family of singular integral equations. We prove the existence-uniqueness theorems in Colombeau space [Formula: see text], 1 ≤ p,q ≤ ∞, employing novel stability estimates (w.r.) to singular perturbations for ε → 0, which imply the statements in the framework of Colombeau generalized functions. In particular, we prove the existence-uniqueness result in [Formula: see text] and [Formula: see text] algebra of Colombeau.
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Evans, Richard B. "The Convergence of the Legendre–Galerkin Spectral Method for Constructing Atmospheric Acoustic Normal Modes." Journal of Theoretical and Computational Acoustics 28, no. 03 (September 2020): 2050002. http://dx.doi.org/10.1142/s2591728520500024.

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The asymptotic rate of convergence of the Legendre–Galerkin spectral approximation to an atmospheric acoustic eigenvalue problem is established, as the dimension of the approximating subspace approaches infinity. Convergence is in the [Formula: see text] Sobolev norm and is based on the existing theory [F. Chatelin, Spectral Approximations of Linear Operators (SIAM, 2011)]. The assumption is made that the eigenvalues are simple. Numerical results that help interpret the theory are presented. Eigenvalues corresponding to acoustic modes with smaller [Formula: see text] norms are especially accurately approximated, even with lower dimensioned basis sets of Legendre polynomials. The deficiencies in the potential applications of the theoretical results are noted in connection with the numerical examples.
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Thien, Austen, Christopher Saldana, and Thomas Kurfess. "Surface Qualification Toolpath Optimization for Hybrid Manufacturing." Journal of Manufacturing and Materials Processing 5, no. 3 (August 27, 2021): 94. http://dx.doi.org/10.3390/jmmp5030094.

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Hybrid manufacturing machine tools have great potential to revolutionize manufacturing by combining both additive manufacturing (AM) and subtractive manufacturing (SM) processes on the same machine tool. A prominent issue that can occur when going from AM to SM is that the SM process toolpath does not account for geometric discrepancies caused by the previous AM step, which leads to increased production times and tool wear, particularly when wire-based directed energy deposition (DED) is used as the AM process. This work discusses a methodology for approximating a part’s surface topology using on-machine contact probing and formulating an optimized SM toolpath using the surface topology approximation. Three different geometric surface approximations were used: triangular, trapezoidal, and a hybrid of both. SM toolpaths were created using each geometric approximation and assessed according to three objectives: reducing total machining time, reducing surface roughness, and reducing cutting force. Different prioritization scenarios of the optimization goals were also investigated. The optimal surface approximation that yielded the most improvement in the optimization was determined to be the hybrid surface topology approximation. Furthermore, it was shown that when the machining time or cutting force optimization goals were prioritized, there was little improvement in the other optimization goals.
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JAVADIMANESH, E., H. HASSANABADI, A. A. RAJABI, H. RAHIMOV, and S. ZARRINKAMAR. "ALPHA-DECAY HALF-LIVES OF DEFORMED NUCLEI BY AN ANGLE-DEPENDENT POTENTIAL." Modern Physics Letters A 27, no. 38 (December 2, 2012): 1250226. http://dx.doi.org/10.1142/s0217732312502264.

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The half-lives of deformed nuclei are reported. We consider an angle-dependent potential which yields multipole approximations. We see that the results are in better agreement with the experimental data when the multipole approximation is solely considered for the daughter nuclei.
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Tuan, Hoang Anh. "The Equivalence of CPA and Hubbard-III-I Approximation in the Two-Band Hubbard Model." Modern Physics Letters B 11, no. 18 (August 10, 1997): 779–84. http://dx.doi.org/10.1142/s0217984997000967.

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We study a two-band Hubbard model using the Coherent Potential Approximation (CPA) and equation of motion decoupling scheme with scattering correction (Hubbard-III-I approximation). We show that above two approximations are completely equivalent to each other for the Periodic Anderson Model (PAM) as well as for the Self-doped Mott System (SMS).
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Dissertations / Theses on the topic "Approximation du potentiel"

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Chacrone, Seddik. "Théorie du potentiel et approximation complexe." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21442.pdf.

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Zeriahi, Ahmed. "Fonctions plurisousharmoniques extremales, approximation et croissance des fonctions holomorphes sur des ensembles algebriques." Toulouse 3, 1986. http://www.theses.fr/1986TOU30105.

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On etudie les proprietes extremales de la "mesure capacitaire d'equilibre" associee a un "condensateur" d'un espace de stein x de dimension pure. On introduit sur un espace de stein parabolique x la notion de fonction extremale associee a un compact kcx. On generalise la theorie des fonctions extremales de siciak-zaharyuta donnant une nouvelle approche de celle-ci basee sur la theorie du potentiel complexe pour l'operateur de monge ampere complexe. On en deduit des resultats sur la theorie des fonctions a croissance controlee a l'infini. On etudie le cas d'un ensemble algebrique de c**(n). Dans ce cas, on demontre des inegalites polynomiales, une version precise d'un theoreme d'approximation de type bernstein-walsh et on en deduit le comportement asymptotique de certaines suites de polynomes orthogonaux pour la mesure d'equilibre. Pour une variete de c**(n) intersection complete, on construit des operateurs lineaires integraux pour la meilleure approximation polynomiale sur un compact avec un controle precis de l'erreur et on en deduit des resultats sur la croissance des fonctions entieres sur de telles varietes
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FONTAINE, EMMANUEL. "Simulation de l'écoulement potentiel engendré par un corps élancé perçant la surface libre à forts nombres de Froude." Marne-la-vallée, ENPC, 1996. http://www.theses.fr/1996ENPC9608.

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La méthode des développements asymptotiques raccordés est utilisée pour étudier l'écoulement potentiel engendré par un corps élancé perçant la surface libre à forts nombres de Froude. Cette méthode permet d'obtenir une solution composite au premier ordre, tenant compte de certaines non-linéarités du problème initial. Le problème simplifié est résolu numériquement en utilisant une méthode mixte Euler-Lagrange. Le domaine et le degré de validité de l'approche sont testés en comparant les résultats obtenus à des solutions analytiques puis à ceux d'expériences réalisées à cet effet.
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Perez, Florent. "Plasmons dans un potentiel unidimensionnel : étude par spectroscopie Raman de fils quantiques gravés." Paris 6, 1998. http://www.theses.fr/1998PA066724.

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Dao, Duy Duc. "Approximation de Hartree-Fock pour les noyaux déformés avec un potentiel général à 2-corps et corrélations d'appariement avec une interaction résiduelle cohérente." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0245.

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Dans ce travail, nous avons étudié l'approximation Hartree-Fock (HF) dans l'espace implusion de façon adaptée à la description des noyaux déformés avec un potentiel nucléon-nucléon (NN) général. La structure d'un tel potentiel a été étudiée à partir de ses symétries et sa construction a été réalisée dans une représentation tensorielle séparable des opérateurs d'impulsion-spin-isospin. En plus, pour traiter des interactions à basse impulsion, nous avons également mis en oeuvre l'approche du groupe de renormalisation par transformation de similarité du potentiel NN. Plusieurs représentations en impulsion ont été étudiées: l'onde plane, l'onde partielle et l'onde plane confinée. L'implémentation numérique de l'approche HF a été validée par comparaison avec un code HF-Skyrme en base d'oscillateur harmonique. Nous avons trouvé que la base d'onde plane confinée offre le plus d'avantages: flexibilité dans le choix du groupe de symétrie auto-cohérente, facilité dans le calcul des éléments de matrice de l'interaction (nucléaire, Coulombienne et la correction cinétique du centre de masse), optimisation des ressources (temps et mémoire). Elle fait intervenir deux paramètres : la taille de boîte de confinement (cube) et la coupure sur l'impulsion individuelle. Nous avons montré que cette coupure a un lien direct avec la coupure d'impulsion de l'interaction et que la taille de boîte est essentiellement liée à celle du noyau. Des calculs de propriétés globales du noyau ont été effectués dans des noyaux magiques et déformés dans le région de masse A < 100 avec divers potentiels récemment dévéloppés. A partir de la solution HF obtenue, les corrélations d'appariement ont été étudiées avec l'interaction résiduelle issue du potentiel NN dans le formalisme HTDA (Highly Truncated Diagonalization Approach). En particulier, la question de la convergence en fonction de l'espace du modèle a été abordée
In this work, we have developed the Hartree-Fock (HF) approximation in momentum space for deformed nuclei with a general nucleon-nucleon (NN) potential. The structure of such a potential has been investigated in momentum space from its symmetries. Its constructions has been realized in a tensorial separable momentum-spin-isospin representation. Moreover, to treat low-momentum interactions, we have implemented the Similarity Renormalization Group approach. Three momentum representations have been studied: the plane-wave, the partial-wave and the confined plane-wave. The numerical implementation has been validated against an existing HF-Skyrme code in the harmonic oscillator basis. We have found that the confined plane-wave basis provides many advantages over the two others, namely: flexible construction of symmetry-adapted bases, efficient calculation of matrix elements (nuclear, Coulomb and center of mass kinetic correction) and optimization in ressources (time and memory). This basis is characterized by two parameters: the confinement box size (cube) which can be essentially related to the nuclear radius and a single-particle momentum cut-off which is directly linked to the cut-off in relative momentum of the interaction. Bulk properties of some spherical and deformed even-even nuclei in the mass region A < 100 have been calculated with recently developed NN potentials. The resulting residual interaction has been derived to study pairing correlations within the Highly Truncated Diagonalization Approach (HTDA). In particular, the question of the convergence with the model space has been addressed
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Véniard, Valérie. "Transitions à un et deux photons dans le spectre continu du potentiel coulombien." Paris 6, 1986. http://www.theses.fr/1986PA066152.

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Calcul par la théorie des perturbations à l'ordre le plus bas par rapport au rayonnement électromagnétique, en traitant exactement le potentiel coulombien, avec une approche non relativiste pour décrire l'électron et l'approximation dipolaire pour l'interaction électron-champ électromagnétique. Cas des transitions à 1 photon dans l'espace des impulsions. Pour les transitions à 2 photons, sommation infinie sur les états intermédiaires au moyen de la fonction de green coulombienne. Analyse de plusieurs cas limites.
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Perez, Florent. "Plasmons dans un potentiel unidimensionnelEtude par spectroscopie Raman de fils quantiques gravés." Phd thesis, Université Pierre et Marie Curie - Paris VI, 1998. http://tel.archives-ouvertes.fr/tel-00285443.

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Nous avons étudiés des fils quantiques dopés de semi-conducteurs gravés par spectroscopie de diffusion Raman. Nous avons observés les excitations du gaz d'électrons. Celles-ci présentent des règles de sélection différentes de celles établies pour les systèmes bi-dimensionnels. Nous avons montré théoriquement qu'elles proviennent de la modification de la structure du champ électromagnétique local provoquée par la géométrie particulière des fils gravés. Pour cela nous avons dû calculer le champ local et l'introduire dans la section efficace de diffusion Raman pour en déduire les règles de sélection de toutes les excitations. Cela a permis de déterminer sans équivoque la nature des excitations qui sont des plasmons. Aucune excitations à une particule ni fluctuations de densité de spin n'a été observées. Nous avons étudié l'évolution continue des dispersions de ces plasmons lorsque la largeur du fil est réduite de 1 micromètre à 30 nm. Jusqu'à 60 nm, celles-ci sont en très bon accord avec les résultats d'un modèle hydrodynamique. Au dessous de 60 nm, la comparaison avec un modèle RPA s'impose. Le plasmon intra-bande dispersif est observé jusqu'à 45 nm, largeur en dessous de laquelle les spectres Raman sont dominés par des excitations localisées qui nécessitent une analyse ultérieure pour en déterminer clairement leur nature. Nous montrons à l'aide du modèle RPA que nous avons atteint la limite quantique pour un fil de largeur 55 nm. Une gamme étroite de fils dont les largeurs sont comprises entre 55 nm à 45 nm permet donc l'étude de gaz strictement unidimensionnel.
Nous avons cherché à déterminer la contribution de la forte illumination dans les conclusions précédentes. Nous avons utilisé pour cela la spectroscopie de magnéto-transmission infra-rouge qui ne modifie pas les conditions d'équilibre du gaz d'électrons. Une largeur critique de 130 nm a été extraite, en dessous de laquelle nous n'avons plus aucun signe de la présence d'électrons libres. La comparaison des mesures Raman et infra-rouge a permis l'établissement et la validation d'un modèle microscopique du potentiel de confinement présent dans les fils. Enfin nous avons fabriqués des échantillons de géométries plus complexes. L'observation et l'analyse par diffusion Raman des plasmons dans ces fils a montré que nous pouvions contrôler la géométrie du potentiel confinant les électrons et a mis en évidence des effets nouveaux tels que le repliement et le confinement de plasmons unidimensionnels.
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Dupuis, Marc. "Modèles de réactions directes et de pré-équilibre quantique pour la diffusion de nucléons sur des noyaux sphériques." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2006. http://tel.archives-ouvertes.fr/tel-00412169.

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Lors d'une collision entre un nucléon et un noyau cible, différentes réactions peuvent se produire, comme les diffusions élastique et inélastique du nucléon, l'échange de charge ... Afin de décrire ces réactions, différents modèles sont utilisés : les modèles de réactions directes, de pré-équilibre et de noyau composé. Le but de ce travail de thèse est d'étudier dans une approche quantique sans paramètre ajustable, les réactions directes et de pré-équilibre pour des diffusions de nucléons sur des noyaux à couches fermées. Une première étude concerne les réactions directes : nous décrivons les diffusions de nucléons en utilisant la matrice-G de Melbourne, représentant l'interaction entre le projectile et un nucléon de la cible, et les fonctions d'onde RPA qui décrivent les états du noyau cible. Cette approche est entièrement microscopique : aucun paramètre ajustable n'est utilisé. Dans la seconde étude, nous nous concentrons sur la diffusion inélastique de nucléons pour de grands transferts d'énergie, processus pour lequel le mécanisme de pré-équilibre prend de l'importance. Différents modèles ont été développés dans la passé pour tenir compte du mécanisme de pré-équilibre. Ils sont basés sur le développement de Born de l'amplitude de transition associée au processus inélastique et utilisent différentes hypothèses qui n'ont jamais vraiment été vérifiées. Nous avons réalisé quelques comparaisons de sections efficaces du second ordre calculées avec et sans les approximations invoquées par ces modèles. Ces études nous permettent de critiquer certaines de ces approximations et de définir quelques directions en vue d'améliorer les modèles quantiques de pré-équilibre.
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Kobeissi, Majida. "Contribution à l'étude des spectres diatomiques : les fonctions canoniques locales optimisées." Lyon 1, 1995. http://www.theses.fr/1995LYO10110.

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Ce travail porte sur le traitement d'une equation differentielle du type: y" +e - u (r) y (r)=0 pour laquelle on recherche les etats lies ou non lies pour divers potentiels u (r) analytiques ou numerique a l'aide de la methode des fonctions canoniques locales optimisees (f. C. L. O). On rappelle d'abord la methode des fonctions canoniques (f. C) et generalisees (f. C. G). On propose par la suite de remplacer les f. C. G. Par des fonctions locales (f. C. L), deduites par des polynomes sur des intervalles bornes par les deux points tournants consecutifs dans le but d'obtenir un gain en precision. Une nouvelle amelioration a ete apportee par les fonctions canoniques locales optimisees (f. C. L. O), pas d'integration et largeur des intervalles variables et ce pour divers potentiel analytiques et numerique. Par une serie de calculs numeriques, on montre le gain en precision et en nombre d'intervalles necessaires, du a l'utilisation de f. C. L. O au lieu de f. C. L. Cette nouvelle version de la methode de f. C a ete utilisee pour calculer les energies de vibration correspondant a divers potentiels: morse, lennard-jones, huffaker et rkr. On illustre la pertinence des apports methodologiques par une comparaison entre les valeurs analytiques exactes des energies de vibration (v = 0 , 13) pour un potentiel de mose pour lequel l'ecart maximal est inferieur a 4. 10#-#6 cm#-#1 alors qu'il est inferieur a 10#-#4 cm#-#1 pour un potentiel de lennard-jones (v = 0, 23). Enfin on presente des resultats pour 99 niveaux vibrationnels de l'etat fondamental de i#2. Par comparaison avec l'experience on obtient un ecart maximal inferieur a 0. 4 cm#-#1. Dans la suite on a regroupe d'autres applications de cette approche pour deux cas particuliers de potentiel avec singularite a l'origine, et potentiel symetrique ainsi que pour le calcul du dephasage caracteristique des collisions elastiques. Tous ces problemes etant decrits par des equations differentielles pour lesquelles la methode de f. C. L. O est appliquee avec succes. Finalement on utilise les fonctions d'onde obtenues par ce procede pour le calcul de divers element de matrice lies aux constantes de distorsion et aux facteurs de frank-condon. La encore on met en evidence une amplification des problemes et une excellente precision des resultats
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Mercier-Depuydt, Eliane. "Contribution a l'etude des collisions ion-atome a basse energie : un modele semi-diabatique pour les courbes de potentiel des ions moleculaires arh**(+*) et hene**(+*)." Paris 6, 1987. http://www.theses.fr/1987PA066522.

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Proposition d'un modele semi-adiabatique pour les ions dissymetriques excitess, formes d'un "coeur" adiabatique et d'un electron externe (de type h::(2)**(+)) en vue de calculs ab initio precis et de la determination des courbes de potentiel necessaires a l'interpretation des collisions a basse energie. Applicaion a arh**(+*): calcul des courbes de potentiel quasidiabatiques pour r = 1,7 - 7 ua; etude du seuil de la reaction ar**(+) + h -> ar**(+) + h (n=2). Application a hene**(+*). Interpretation des oscillations de rosenthal observees dans la section efficace totale d'excitation; calcul des courbes de potentiel ab initio adiabatiques du coeur hene**(2+), des coefficients d'einstein entre les etats moleculaires de ce coeur et des etats quasi diabatiques de coeur par extension de la methode de l'hamiltonien effectif de b. Levy
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Books on the topic "Approximation du potentiel"

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Bartόk-Pártay, Albert. The Gaussian Approximation Potential. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9.

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Arakelian, N., P. M. Gauthier, and G. Sabidussi, eds. Approximation, Complex Analysis, and Potential Theory. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-010-0979-9.

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The Gaussian approximation potential: An interatomic potential derived from first principles quantum mechanics. Heidelberg: Springer, c2010., 2010.

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Baumeister, Kenneth J. Combining comparison functions and finite element approximations in CFD. [Washington, DC]: National Aeronautics and Space Administration, 1995.

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Limit theorems of polynomial approximation with exponential weights. Providence, R.I: American Mathematical Society, 2008.

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G, Vaĭnikko, ed. Periodic integral and pseudodifferential equations with numerical approximation. Berlin: Springer, 2002.

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Rossetti, Cesare. On the bound states of power law center potentials. Bologna: Editrice Compositori, 1989.

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N, Demkov I͡U. Zero-range potentials and their applications in atomic physics. New York: Plenum Press, 1988.

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1969-, Michel Volker, ed. Multiscale potential theory: With applications to geoscience. Boston: Birkhäuser, 2004.

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Burglind, Jöricke, ed. The uncertainty principle in harmonic analysis. Berlin: Springer-Verlag, 1994.

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Book chapters on the topic "Approximation du potentiel"

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Gauthier, Paul M. "Uniform approximation." In Complex Potential Theory, 235–71. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0934-5_6.

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Bliedtner, Jürgen, and Wolfhard Hansen. "Approximation by Continuous Potentials." In Potential Theory, 53–58. Boston, MA: Springer US, 1988. http://dx.doi.org/10.1007/978-1-4613-0981-9_7.

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Verdera, Joan. "Removability, capacity and approximation." In Complex Potential Theory, 419–73. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-011-0934-5_10.

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Bartók-Pártay, Albert. "Introduction." In The Gaussian Approximation Potential, 1–3. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_1.

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Bartók-Pártay, Albert. "Representation of Atomic Environments." In The Gaussian Approximation Potential, 5–22. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_2.

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Bartók-Pártay, Albert. "Gaussian Process." In The Gaussian Approximation Potential, 23–31. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_3.

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Bartók-Pártay, Albert. "Interatomic Potentials." In The Gaussian Approximation Potential, 33–49. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_4.

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Bartók-Pártay, Albert. "Computational Methods." In The Gaussian Approximation Potential, 51–56. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_5.

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Bartók-Pártay, Albert. "Results." In The Gaussian Approximation Potential, 57–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_6.

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Bartók-Pártay, Albert. "Conclusion and Further Work." In The Gaussian Approximation Potential, 83–84. Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-642-14067-9_7.

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Conference papers on the topic "Approximation du potentiel"

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de Hauteclocque, Guillaume, Flávia Rezende, Olaf Waals, and Xiao-Bo Chen. "Review of Approximations to Evaluate Second-Order Low-Frequency Load." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83407.

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The second order low-frequency loads are one of main sources of excitation for moored systems. These loads are usually decomposed into the quadratic part, contributed only by first order quantities and potential part contributed by the second order potentials. In shallow water the second order incoming and diffracted potentials give a significant contribution to the low frequency forces. Therefore, the accuracy on the determination of this parcel of the low-frequency loads is a key issue for the assessment of mooring lines and operability of systems moored in shallow water area, as for example LNG terminals. Due to the complexity in computing the second order diffraction potential, which would involve a non-homogeneous free surface boundary condition, the so-called Pinkster approximation has been proposed. This approximation is based on the assumption that the major contribution to the potential part of low-frequency loads is given by the second order potential of the undisturbed incoming waves. The methods to compute the wave forces related to the second order potentials are based on scaling of the first order wave induced forces. Another approximation recently formulated in Chen and Rezende consists of developing the second-order bi-frequency load into a series of different orders of the difference frequency. The potential contribution to the term proportional to the difference-frequency can be evaluated efficiently by involving an integral over a small zone on the free surface around the body. In the present paper, the existing approximations are revisited and compared to analytical solution of exact second-order load on a vertical cylinder and for the case of floating body (LNG) in shallow water. Some guidelines in the practical use of different approximations will be derived.
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Wemhoff, Aaron P., and Van P. Carey. "Surface Tension Evaluation Via Thermodynamic Analysis of Statistical Data From Molecular Dynamics Simulations." In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56690.

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Surface tension determination of liquid-vapor interfaces of polyatomic fluids using traditional methods has shown to be difficult due to the requirement of evaluating complex intermolecular potentials. However, analytical techniques have recently been developed that determine surface tension solely by means of the characteristics of the interfacial region between the bulk liquid and vapor regions. A post-simulation application of the excess free energy density integration (EFEDI) method was used for analysis of the resultant density profile of molecular dynamics (MD) simulations of argon using a simple Lennard-Jones potential and diatomic nitrogen using a two-center Lennard-Jones potential. MD simulations were also run for an approximation of nitrogen using the simple Lennard-Jones potential. In each MD simulation, a liquid film was initialized between vapor regions and NVE-type simulations were run to equilibrium. The simulation domain was divided into bins across the interfacial region for fluid density collection, and the resultant interfacial region density profile was used for surface tension evaluation. Application of the EFEDI method to these MD simulation results exhibited good approximations to surface tension as a function of temperature for both a simple and complex potential.
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McCormick, Michael E., and Jeffrey Cerquetti. "Alternative Wave-Induced Force and Moment Expressions for a Fixed, Vertical, Truncated, Circular Cylinder in Waters of Finite Depth." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51330.

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Two user-friendly expressions for the horizontal and vertical wave-induced forces on fixed, truncated circular cylinders are presented. The approximation of the horizontal force is that of van Oortmerssen, and that of the vertical force is based on a solution of the Laplace equation with a matching radial-force condition at the internal-external interface. The velocity potential resulting from the solution is assumed to be finite at the origin of the radial coordinate. Results obtained from both approximations are compared with results obtained from the rigorous analysis of Garrett. Also, results from the Froude-Krylov approximation for the vertical force are presented for the sake of comparison. The van Oortmerssen are shown to coalesce with the Garrett results for ka &gt; 1.5, while the vertical force results compare well over the ka range studied.
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Monroy, Charles, Guillaume de Hauteclocque, and Xiao-Bo Chen. "Systematic Accuracy Assessment of Two Frequently Used QTF Approximations in the Case of a Rectangular Barge." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24600.

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This paper presents numerical results of the monodirectional second order forces acting on a rudimentory FPSO hull shape. The exact calculation of second order loads through potential theory is computationally challenging and requires the evaluation of a slowly-convergent free surface integral. In practice, this integral is often neglected as it is widely assumed that it does not contribute significantly to the overall load and few commercial seakeeping software propose this option anyway. An even rougher and widely used approximation consists in expressing the second order loads occuring at a non-zero difference frequency from the mean drift loads. It is called the Newman’s approximation; it enables serious CPU time gains, but at the cost of a worse accuracy. The object of this paper is to investigate on a simple case the accuracy of each of these two approximations (without the free surface integral and Newman’s approximation) and the influence of parameters such as the water depth and the sea state wave length. Depending on the resonant period of the considered mooring system, it may give some insight on a good compromise between CPU time and accuracy when choosing the way of determing the second order loads.
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Ushenin, Konstantin, Tatyana Nesterova, Dmitry Shmarko, and Artem Razumov. "Approximation of Action Potential in Populations of Cardiomyocyte Electrophysiology Models." In 2019 Ural Symposium on Biomedical Engineering, Radioelectronics and Information Technology (USBEREIT). IEEE, 2019. http://dx.doi.org/10.1109/usbereit.2019.8736682.

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LÓPEZ-QUELLE, M., L. N. SAVUSHKIN, S. MARCOS, and P. BERNARDOS. "PSEUDO SPIN-ORBIT POTENTIAL IN THE RELATIVISTIC HARTREE-FOCK APPROXIMATION." In Proceedings of the Conference “Bologna 2000: Structure of the Nucleus at the Dawn of the Century”. WORLD SCIENTIFIC, 2001. http://dx.doi.org/10.1142/9789812799753_0070.

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Nauenberg, M. "COHERENT WAVE-PACKETS AND SEMICLASSICAL APPROXIMATION IN THE COULOMB POTENTIAL." In Proceedings of the International Symposium. WORLD SCIENTIFIC, 1994. http://dx.doi.org/10.1142/9789814503839_0025.

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Kime, Katherine A. "Numerical Approximation of Bilinear Control of the Schroedinger Equation." In ASME 2005 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/detc2005-84254.

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We consider the one-dimensional Schroedinger equation in which the control is a time-dependent rectangular potential barrier/well. This is a bilinear control problem, as the potential multiplies the state. Differential geometric methods have been used to treat the bilinear control of systems of finitely many ODEs, and have been applied to the Schroedinger equation (quantum systems). In this paper we will calculate, using MATLAB, explicit controls which steer localized initial data to localized terminal data. These will be obtained using the Crank-Nicolson approximation, in which both space and time are discretized. If one semi-discretizes, in space, one obtains a bilinear control problem for a system of finitely many ODEs. One may pass from the semi-discretized system to Crank-Nicolson using the trapezoid rule. Thus the controls we calculate may be used to construct approximations to controls for the system of ODEs.
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Pandey, Parul, and Dario Pompili. "MobiDiC: Exploiting the untapped potential of mobile distributed computing via approximation." In 2016 IEEE International Conference on Pervasive Computing and Communications (PerCom). IEEE, 2016. http://dx.doi.org/10.1109/percom.2016.7456515.

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Tsukerman, I. A. "Node And Edge Element Approximation Of Discontinuous Fields And Potentials." In 1993 Digests of International Magnetics Conference. IEEE, 1993. http://dx.doi.org/10.1109/intmag.1993.642057.

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Reports on the topic "Approximation du potentiel"

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Cogan, James. Some Potential Errors in Satellite Wind Estimates Using the Geostrophic Approximation and the Thermal Wind. Fort Belvoir, VA: Defense Technical Information Center, June 1993. http://dx.doi.org/10.21236/ada269784.

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Fontanari, Claudia, Antonella Palumbo, and Chiara Salvatori. The Updated Okun Method for Estimation of Potential Output with Broad Measures of Labor Underutilization: An Empirical Analysis. Institute for New Economic ThinkingInstitute for New Economic Thinking Working Paper Series, April 2021. http://dx.doi.org/10.36687/inetwp158.

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This paper extends to different indicators of labor underutilization the Updated Okun Method (UOM) for estimation of potential output proposed in Fontanari et al (2020), which, from a demand-led growth perspective, regards potential output as an empirical approximation to full-employment output, as in A.M.Okun’s (1962) original method. Based on the apparent incapability of the official rate of unemployment to fully account for labor underutilization, in this paper we offer estimates of Okun’s law both with broad unemployment indicators and with an indicator of ‘standardized hours worked’ which we propose as a novel measure of the labor input. The paper reflects on the possible different empirical measures of full employment. The various measures of potential output that we extract from our analysis show greater output gaps than those produced by standard methods, thus highlighting a systematic tendency of the latter to underestimate potential output. Output gaps that underestimate the size of the output loss or that tend to close too soon during recovery, may produce a bias towards untimely restriction.
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