共查询到20条相似文献,搜索用时 15 毫秒
1.
N. Mujica R. Wunenburger S. Fauve 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(2):209-213
We report an experimental study of the scattering of a sound wave of frequency f by a surface vibrating at frequency F. Both the Doppler shift at the vibrating surface and acoustic nonlinearities in the bulk of the fluid, generate the frequencies
f±nF (n integer) in the spectrum of the scattered wave. We show that these two contributions can be separated because they scale
differently with respect to the vibration frequency and to the distance between the vibrating scatterer and the detector.
We determine the parameter ranges in which one or the other mechanism dominates and present quantitative studies of these
two regimes.
Received 2 December 2002 / Received in final form 27 March 2003 Published online 4 June 2003
RID="a"
ID="a"e-mail: fauve@physique.ens.fr
RID="b"
ID="b"UMR 8550 相似文献
2.
R. Berthet S. Fauve R. Labbé 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):237-242
We present a study of sound propagation through a single vortex by direct numerical simulations (DNS) compared to experimental
measurements. We analyse the amplitude and the phase shift of the sound wave when it interacts with the vortical flow and
we display the focusing effects produced by the vortex. We show that the turbulent fluctuations have a little effect on the
sound phase shift whereas they induce a strong defocusing effect on the sound amplitude.
Received 9 October 2002 / Received in final form 20 January 2003 Published online 1st April 2003
RID="a"
ID="a"e-mail: rberthet@lps.ens.fr
RID="b"
ID="b"UMR CNRS 8550 相似文献
3.
L.F. Lemmens F. Brosens J.T. Devreese 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(2):195-202
A full analysis of domain structure using a micromagnetic model is developed in order to get a clear insight into the behaviour
of transverse initial susceptibility as a function of dc applied field for thin films and bilayers exhibiting both in-plane
and perpendicular anisotropy. The numerical simulations are in good agreement with available experimental results in case
of single layers with the so-called stripe domain pattern while some predictions are done for bilayers. As the main result,
it is shown that in low field, the transverse initial susceptible cannot be interpreted without the knowledge of the static
domain pattern while, above saturation, it is only affected by the in-plane anisotropy.
Received 10 October 2002 Published online 4 February 2003
RID="a"
ID="a"e-mail: ml@lpmtm.univ-paris13.fr
RID="b"
ID="b"UMR CNRS 8634 相似文献
4.
Th. Desaive M. Hennenberg G. Lebon 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(4):641-647
In this work, we study the problem of onset of thermal convection in a rotating saturated porous medium heated from below.
The effect of rotation is restricted to the Coriolis force, neglecting thus the centrifugal effects, the porous medium is
described by Brinkman's model. The linear eigenvalue problem is solved by means of a modified Galerkin method. The behavior
of the critical temperature gradient is discussed in terms of various parameters of the system for both stationary and overstable
convections. Finally a weakly nonlinear analysis is provided to derive amplitude equations and to study the onset of Küppers-Lortz
instability.
Received 24 June 2002 / Received in final form 11 September 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: tdesaive@ulg.ac.be 相似文献
5.
A theoretical model based on the competition between short-pitch and long-pitch types of helical order is developed for thin
films of antiferroelectric smectic liquid crystals. In the case of the “bookshelf” structure of the film and non-polar surfaces,
subsurface perturbations of the ordering are found out analytically. Corresponding contributions to the free energies of the
different phases are analysed. The possibility of sufficient influence of the boundaries on phase sequences is predicted even
in the case of weak surface anchoring. A consistent explanation of the controversial experimental information is given; further
ways of experimental justification of the model assumptions are discussed.
Received 23 May 2002
RID="a"
ID="a"e-mail: mgorkoun@uos.de 相似文献
6.
We present a quantum mechanical framework for defining the statistics of measurements of
, A(t) being a quantum mechanical variable. This is a generalization of the so-called full counting statistics proposed earlier for DC electric currents. We develop an influence functional formalism that allows us to study the quantum system along with the measuring device while fully accounting for the back action of the detector on the system to be measured. We define the full counting statistics of an arbitrary variable by means of an evolution operator that relates the initial and final density matrices of the measuring device. In this way we are able to resolve inconsistencies that occur in earlier definitions. We suggest two schemes to observe the so defined statistics experimentally.Received: 30 June 2003, Published online: 15 October 2003PACS:
73.50.Td Noise processes and phenomena - 73.23.-b Electronic transport in mesoscopic systems - 74.40.+k Fluctuations (noise, chaos, nonequilibrium superconductivity, localization, etc.) 相似文献
7.
B. Eckhardt R. Pandit 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(3):373-378
We consider the effects of a shear on velocity fluctuations in a flow. The shear gives rise to a transient amplification that
not only influences the amplitude of perturbations but also their time correlations. We show that, in the presence of white
noise, time correlations of transversal velocity components are exponential and that correlations of the longitudinal components
are exponential with an algebraic prefactor. Cross correlations between transversal and downstream components are strongly
asymmetric and provide a clear indication of non-normal amplification. We suggest experimental tests of our predictions.
Received 26 February 2002 / Received in final form 11 March 2003 Published online 20 June 2003
RID="a"
ID="a"e-mail: bruno.eckhardt@physik.uni-marburg.de
RID="b"
ID="b"Also at: Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India 相似文献
8.
S. Hofmann 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):195-200
The nuclear shell model predicts that the next doubly magic shell-closure beyond 208Pb is at a proton number between Z = 114 and 126 and at a neutron number N = 184. The outstanding aim of experimental investigations is the exploration of this region of spherical “Superheavy Elements”.
This article describes the experiments that were performed at the GSI SHIP. They resulted in an unambiguous identification
of elements 107 to 112. They were negative so far in searching for elements 113, 116 and 118 at SHIP; however, positive results
were reported from experiments in Dubna on elements 114 and 116 and from experiments in Berkeley on element 118. The measured
decay data are compared with theoretical predictions. Some aspects concerning the reaction mechanism and the use of radioactive
beams are also presented.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: S.Hofmann@gsi.de 相似文献
9.
A. Khelif B. Djafari-Rouhani Ph. Lambin 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,21(3):437-445
The vibrational and electronic spectra of a semi-infinite crystal with a planar surface are modified by the presence of surface
inhomogeneities or roughness such as ridges or grooves, quantum wires or tips. We develop a Green's function formalism to
investigate the localized and resonant acoustic modes of shear horizontal polarization associated with the surface of a substrate
supporting a single and a periodic array of wires. Each material is assumed to be an isotropic elastic medium. The calculation
can be applied to an arbitrary choice of the shape and elastic parameters of the wires. The surface modes are obtained as
well-defined peaks of the densities of states (DOS). In this paper, we calculate the variation of the density of states associated
with the adsorption of a single wire, and the dispersion curves of the surface modes for a periodic array of wires on the
flat surface of a substrate. We discuss their behaviors as a function of the elastic parameters and the relationship between
resonant modes of the single wire and dispersion curves of the surface modes for a periodic structure.
Received 6 December 2000 相似文献
10.
V. Baru J. Haidenbauer C. Hanhart J.A. Niskanen 《The European Physical Journal A - Hadrons and Nuclei》2003,16(3):437-446
We present a new parameterization of the trinucleon wave function. As a novel feature a separable parameterization for the
complete wave function is given. In this way any calculation that considers two-body currents only is largely simplified.
To demonstrate this we calculate the π3He scattering length in chiral-perturbation theory. We find reasonable agreement with experimental values inferred from data
on level shifts in pionic 3He bound states. The relevance of the π-triton system for an alternative determination of the πN scattering lengths is discussed.
Received: 12 August 2002 / Accepted: 25 November 2002 / Published online: 25 February 2003
RID="a"
ID="a"e-mail: c.hanhart@fz.juelich.de
Communicated by V. Vento 相似文献
11.
Cristóbal López Emilio Hernández-García 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,28(3):353-359
We study the influence of diffusion on the scaling properties of the first order structure function, S1, of a two-dimensional chaotically advected passive scalar with finite lifetime, i.e., with a decaying term in its evolution equation. We obtain an analytical expression for S1 where the dependence on the diffusivity, the decaying coefficient and the stirring due to the chaotic flow is explicitly
stated. We show that the presence of diffusion introduces a crossover length-scale, the diffusion scale (Ld), such that the scaling behaviour for the structure function is analytical for length-scales shorter than Ld, and shows a scaling exponent that depends on the decaying term and the mixing of the flow for larger scales. Therefore,
the scaling exponents for scales larger than Ld are not modified with respect to those calculated in the zero diffusion limit. Moreover, Ld turns out to be independent of the decaying coefficient, being its value the same as for the passive scalar with infinite
lifetime. Numerical results support our theoretical findings. Our analytical and numerical calculations rest upon the Feynmann-Kac
representation of the advection-reaction-diffusion partial differential equation.
Received 18 March 2002 Published online 31 July 2002 相似文献
12.
J. Tempere S.N. Klimin I.F. Silvera J.T. Devreese 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(3):329-338
The properties of ripplonic polarons in a multielectron bubble in liquid helium are investigated on the basis of a path-integral
variational method. We find that the two-dimensional electron gas can form deep dimples in the helium surface, or ripplopolarons,
to solidify as a Wigner crystal. We derive the experimental conditions of temperature, pressure and number of electrons in
the bubble for this phase to be realized. This predicted state is distinct from the usual Wigner lattice of electrons: it
melts by dissociation of the ripplopolarons when the electrons shed their localizing dimple as the pressure on the multielectron
bubble drops below a critical value.
Received 20 February 2003 Published online 11 April 2003
RID="a"
ID="a"Also at: TU Eindhoven, Eindhoven, The Netherlands e-mail: devreese@uia.ua.ac.be 相似文献
13.
A new and general approach is proposed to analyze the dynamics of a colloidal particle interacting with a nearby wall. This
analysis can be used to determine the acting forces even when the system is non-stationary. As an illustration, we use total
internal reflection microscopy to investigate the forces acting on a polystyrene sulfate latex particle as it is receding
from a charged glass surface.
Received 10 October 2002 Published online: 16 April 2003
RID="a"
ID="a"Present address: Department of Polymer Physics, BASF Aktiengesellschaft, 67056 Ludwigshafen, Germany
RID="b"
ID="b"Present address: Arryx. Inc., Chicago, IL 60601, USA 相似文献
14.
Vivarès D Belloni L Tardieu A Bonneté F 《The European physical journal. E, Soft matter》2002,9(1):15-25
We present the experimental and theoretical background of a method to characterize the protein-protein attractive potential
induced by one of the mostly used crystallizing agents in the protein-field, the poly(ethylene glycol) (PEG). This attractive
interaction is commonly called, in colloid physics, the depletion interaction. Small-Angle X-ray Scattering experiments and
numerical treatments based on liquid-state theories were performed on urate oxidase-PEG mixtures with two different PEGs (3350
Da and 8000 Da). A “two-component” approach was used in which the polymer-polymer, the protein-polymer and the protein-protein
pair potentials were determined. The resulting effective protein-protein potential was characterized. This potential is the
sum of the free-polymer protein-protein potential and of the PEG-induced depletion potential. The depletion potential was
found to be hardly dependent upon the protein concentration but strongly function of the polymer size and concentration. Our
results were also compared with two models, which give an analytic expression for the depletion potential.
Received 29 April 2002
RID="a"
ID="a"Present address: CRMC2-CNRS, Campus de Luminy, case 913, F-13288 Marseille Cedex 09, France; e-mail: vivares@crmc2.univ-mrs.fr
RID="b"
ID="b"e-mail: bonnete@crmc2.univ-mrs.fr
RID="c"
ID="c"Laboratory associated to Universities Aix-Marseille II and III. 相似文献
15.
H. Mahmud C.N. Davids P.J. Woods T. Davinson A. Heinz J.J. Ressler K. Schmidt D. Seweryniak J. Shergur A.A. Sonzogni W.B. Walters 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):85-87
78Kr beams were used to bombard 58Ni, 92Mo and 96Ru, producing three new, odd-odd, proton-emitting isotopes, 130Eu, 164mIr and 170Au. Preliminary experimental and theoretical results will be presented in this paper.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: mahmud@ph.ed.ac.uk 相似文献
16.
We analyze the deviations from Maxwell-Boltzmann statistics found in recent experiments studying velocity distributions in
two-dimensional granular gases driven into a non-equilibrium stationary state by a strong vertical vibration. We show that
in its simplest version, the “stochastic thermostat” model of heated inelastic hard spheres, contrary to what has been hitherto
stated, is incompatible with the experimental data, although predicting a reminiscent high-velocity stretched-exponential
behavior with an exponent 3/2. The experimental observations lead to refine a recently proposed random restitution coefficient
model. Very good agreement is then found with experimental velocity distributions within this framework, which appears self-consistent
and further provides relevant probes to investigate the universality of the velocity statistics.
Received: 27 May 2002 / Accepted: 6 May 2003 / Published online: 27 May 2003
RID="a"
ID="a"e-mail: Alain.Barrat@th.u-psud.fr 相似文献
17.
J.S. Al-Khalili 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):115-120
Halo nuclei are characterised by their weak binding, large spatial extent and hence a quite pronounced, yet highly correlated,
few-body structure. This is typically in terms of a well-defined core plus one or more valence nucleons. Over the past decade
the properties of halo nuclei have been studied theoretically using a range of reaction models, many of which having served
us well for half a century or more in the study of less exotic, “mean-field”, nuclei. However, it is now clear that for many
reactions with halo nuclei, it is not appropriate to disentangle (factorise out) the structure information from the reaction
information. That is, the few-body nature of these systems requires few-body reaction models in which the nuclear structure
and reaction mechanisms are necessarily entangled. This talk will briefly review the physical assumptions made by various
reaction models, and point to areas where progress is being made to extend their range of applicability in order to provide
further insights into halo structure.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: j.al-khalili@surrey.ac.uk 相似文献
18.
19.
D. Vignolles A. Audouard L. Brossard S. Pesotskii R. Lyubovskii M. Nardone E. Haanappel R. Lyubovskaya 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):53-61
Interlayer magnetoresistance and magnetisation of the quasi-two dimensional organic metal (BEDT-TTF)8Hg4Cl12(C6H5Br)2 have been investigated in pulsed magnetic fields extending up to 60 T and 33 T, respectively. About fifteen fundamental frequencies,
composed of linear combinations of only three basic frequencies, are observed in the oscillatory spectra of the magnetoresistance.
The dependencies of the oscillation amplitude on the temperature and on the magnitude and orientation of the magnetic field
are analyzed in the framework of the conventional two-dimensional Lifshitz-Kosevitch (LK) model. This model is implemented
by damping factors which accounts for the magnetic breakthrough occurring between electron and hole orbits yielding conventional
Shubnikov-de Haas closed orbits (model of Falicov and Stachowiak) and quantum interferometers. In particular, a quantum interferometer
enclosing an area equal to the first Brillouin zone area is evidenced. The LK model consistently accounts for the temperature
and magnetic field dependence of the oscillation amplitude of this interferometer. On the contrary, although this model formally
accounts for almost all of the observed oscillatory components, it fails to give consistent quantitative data in most other
cases.
Received 4 September 2002 / Received in final form 14 November 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: audouard@insa-tlse.fr
RID="b"
ID="b"UMR 5830: Unité Mixte de Recherche CNRS - Université Paul Sabatier - INSA de Toulouse
RID="c"
ID="c"UMS 5642: Unité Mixte de Service CNRS - Université Paul Sabatier - INSA de Toulouse 相似文献
20.
L.V. Grigorenko R.C. Johnson I.G. Mukha I.J. Thompson M.V. Zhukov 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):125-129
The theoretical approach to the two-proton radioactivity and three-body decays developed in (L.V. Grigorenko, R.C. Johnson,
I.G. Mukha, I.J. Thompson, M.V. Zhukov, Phys. Rev. Lett. 85, 22 (2000) and to be published in Phys. Rev. C) is applied to the range of light nuclear systems. We study nuclear structures,
widths, and momentum correlations for the decay fragments. Strong contradictions with experiment, as well as effects of special
interest, are found in 12O and 16Ne nuclei.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: l.grigorenko@surrey.ac.uk 相似文献