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101.
I. Haysak Yu. Fekete V. Morokhovych S. Chalupka M. Salak 《Czechoslovak Journal of Physics》2005,55(5):541-554
Based on the numeric solution of a system of coupled channels for vector mesons (S-and D-waves mixing)and for tensor mesons (P- and F- waves mixing) mass spectrum and wave functions of a family of vector mesons q
in triplet states a e obtained. The calculations are performed using a well-known Cornell potential with a mixed Lorentz- structure of the confinement term. The spin-dependent part of the potential is taken from the Breit-Fermi approach.The effect of irregular terms of the potential is considered within the framework of the perturbation theory and/or of the configuration interaction approach, modified for a system of coupled equations. It is shown that even a small integral contribution of the D-wave to the total wave function of q
system is very impotant for the calculation of certain characteristics of the meson states. 相似文献
102.
Existence and asymptotic stability for evolution problems on manifolds with damping and source terms
Marcelo M. Cavalcanti Valéria N. Domingos Cavalcanti 《Journal of Mathematical Analysis and Applications》2004,291(1):109-127
One considers the nonlinear evolution equation with source and damping terms
103.
ShaoJiFENG DeXingFENG 《数学学报(英文版)》2004,20(6):1057-1072
For wave equations with variable coefficients on regions which are not necessarily smooth, we study the energy decay rate when a nonlinear damping is applied on a suitable subrigion. 相似文献
104.
B. Macke B. Ségard 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(1):125-141
This paper deals with the apparent superluminal propagation of electromagnetic pulses in a linear dispersive medium. One specifically
examines the possibility that the pulse leaving the medium may be nearly identical to the incident one (low distortion) and
in significant advance of it (strongly negative group-delays). Favourable conditions are obtained in a dilute medium where
the required anomalous dispersion originates in an ensemble of narrow absorption or gain lines. Analytical expressions of
the advancement of the pulse centre-of-gravity and of the lowest order distortion are established from the transfer-function
of the medium. The experiments already achieved with arrangements involving a single absorption-line or a gain-doublet are
analysed in detail and compared. The considerable difficulties to overcome in order to attain advancements comparable to the
pulse width without important distortion are pointed out. New and promising schemes involving a narrow dip in a gain profile
or absorption-doublets are proposed.
Received 4 July 2002 / Received in final form 8 November 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: bruno.macke@univ-lille1.fr
RID="b"
ID="b"Unité Mixte de Recherche de l'Université et du CNRS (UMR 8523) 相似文献
105.
A method is proposed to create materials with a desired refraction coefficient, possibly negative one. The method consists of embedding into a given material small particles. Given n0(x), the refraction coefficient of the original material in a bounded domain , and a desired refraction coefficient n(x), one calculates the number N(x) of small particles, to be embedded in D around a point xD per unit volume of D, in order that the resulting new material has refraction coefficient n(x). 相似文献
106.
We point out that, due to the use of static nucleon propagators in Heavy-Baryon Chiral Perturbation Theory (HBχPT), the current calculations of the nucleon-nucleon potential miss certain contributions starting at two loops. These contributions
give rise to contact interactions, which are both parametrically and numerically more important than the so-called NNLO potentials.
They show a peculiar dependence on the light-quark masses, which should be taken into account when performing chiral extrapolations
of lattice data. However, they do not appear to have an impact on phenomenology since they can be absorbed into redefinitions
of unknown parameters which are usually fitted to data. 相似文献
107.
H. Mardanpour H. R. Amir-Ahmadi A. Deltuva K. Itoh N. Kalantar-Nayestanaki T. Kawabata H. Kuboki Y. Maeda J. G. Messchendorp S. Sakaguchi H. Sakai N. Sakamoto Y. Sasamoto M. Sasano K. Sekiguchi K. Suda Y. Takahashi T. Uesaka H. Witała K. Yako 《The European Physical Journal A - Hadrons and Nuclei》2007,31(3):383-391
High-precision vector and tensor analyzing powers of elastic deuteron-proton ( d + p) scattering have been measured at intermediate energies to investigate effects of three-nucleon forces. Angular distributions
in the range of 70°-120° in the center-of mass frame for incident-deuteron energies E
d
lab = 130 and 180 MeV were obtained using the RIKEN facility. The beam polarization was unambiguously determined by measuring
the ^12C (d, α)^10B(2+) reaction at 0°. Results of the measurements are compared with state-of-the-art three-nucleon calculations. The present modeling of nucleon-nucleon
forces and its extension to the three-nucleon system is not sufficient to describe the high-precision data consistently and
requires, therefore, further investigation. 相似文献
108.
R. Bachelard A. Antoniazzi C. Chandre D. Fanelli X. Leoncini M. Vittot 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,42(1):125-132
The intensity of an electromagnetic wave interacting self-consistently
with a beam of charged particles as in a free electron laser, displays large
oscillations due to an aggregate of particles, called the macro-particle. In
this article, we propose a strategy to stabilize the intensity by re-shaping
the macro-particle. This strategy involves the study of the linear stability
(using the residue method) of selected periodic orbits of a mean-field model. As
parameters of an additional perturbation are varied, bifurcations occur in the
system which have drastic effect on the modification of the self-consistent
dynamics, and in particular, of the macro-particle. We show how to obtain an
appropriate tuning of the parameters which is able to strongly decrease the
oscillations of the intensity without reducing its mean-value. 相似文献
109.
We investigate short-range correlations in nuclear and hypernuclear matter. Self-energies due to short-range correlations
and their influence on the nucleon and Λ -hyperon spectral functions are described in an approach accounting for a realistic
treatment of mean-field dynamics and a self-consistently derived quasi-particle interaction. Landau-Migdal theory is used
to derived the short-range interaction from a phenomenological Skyrme energy density functional, subtracting the long-range
pionic contributions to the nucleonic spectral functions. We discuss our results for different hyperon-baryon ratios to show
the influence of strangeness on the correlations in hypernuclear matter. 相似文献
110.
Many oscillatory biological systems show periodic travelling waves. These are often modelled using coupled reaction-diffusion equations. However, the effects of different movement rates (diffusion coefficients) of the interacting components on the predictions of these equations are largely unknown. Here we investigate the ways in which varying the diffusion coefficients in such equations alters the wave speed, time period, wavelength, amplitude and stability of periodic wave solutions. We focus on two sets of kinetics that are commonly used in ecological applications: lambda-omega equations, which are the normal form of an oscillatory coupled reaction-diffusion system close to a supercritical Hopf bifurcation, and a standard predator-prey model. Our results show that changing the ratio of the diffusion coefficients can significantly alter the shape of the one-parameter family of periodic travelling wave solutions. The position of the boundary between stable and unstable waves also depends on the ratio of the diffusion coefficients: in all cases, stability changes through an Eckhaus (‘sideband’) instability. These effects are always symmetrical in the two diffusion coefficients for the lambda-omega equations, but are asymmetric in the predator-prey equations, especially when the limit cycle of the kinetics is of large amplitude. In particular, there are two separate regions of stable waves in the travelling wave family for some parameter values in the predator-prey scenario. Our results also show the existence of a one-parameter family of travelling waves, but not necessarily a Hopf bifurcation, for all values of the diffusion coefficients. Simulations of the full partial differential equations reveals that varying the ratio of the diffusion coefficients can significantly change the properties of periodic travelling waves that arise from particular wave generation mechanisms, and our analysis of the travelling wave families assists in the understanding of these effects. 相似文献