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1.
Courty S Dollet B Kassner K Renault A Graner F 《The European physical journal. E, Soft matter》2003,11(1):53-59
We investigate the mechanical properties of a two-dimensional amorphous solid. It is formed spontaneously by the adsorption
of a protein (the β-lactoglobulin) at the surface of water. We measure its mechanical response in both elastic and plastic
regimes by applying a point-like force (using a glass fiber). We compare our results with previous measurements of shear moduli
using a floating torsion device.
Received: 10 February 2003 / Accepted: 23 April 2003 / Published online: 27 May 2003
RID="a"
ID="a"Present address: Cavendish Laboratory, Madingley Road, Cambridge, CB3 0HE, UK; e-mail: sc374@phy.cam.ac.uk
RID="b"
ID="b"e-mail: graner@ujf-grenoble.fr 相似文献
2.
H. Caps H. Decauwer M.-L. Chevalier G. Soyez M. Ausloos N. Vandewalle 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):115-119
We report an experimental study of aqueous foam imbibition in microgravity with strict mass conservation. The foam is in a
Hele-Shaw cell. The bubble edge width ℓ is measured by image analysis. The penetration of the liquid in the foam, the foam
imbibition, the foam inflation, and the rigidity loss are shown all to obey strict diffusion processes. The motion of bubbles
needed for the foam inflation is a slow two-dimensional process with respect to the one-dimensional capillary rise of liquid.
The foam is found to imbibes faster than it inflates.
Received 20 May 2002 / Received in final form 21 January 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: herve.caps@ulg.ac.be 相似文献
3.
M. Abdel-Bary S. Abdel-Samad R. Bilger K.-Th. Brinkmann H. Clement S. Dshemuchadse E. Dorochkevitch H. Dutz W. Eyrich A. Erhardt D. Filges A. Filippi H. Freiesleben M. Fritsch R. Geyer A. Gillitzer D. Hesselbarth B. Jakob L. Karsch K. Kilian H. Koch J. Kreß E. Kuhlmann S. Marcello S. Marwinski S. Mauro W. Meyer P. Michel K. Möller H. P. Morsch L. Naumann N. Paul M. Richter E. Roderburg M. Rogge A. Schamlott M. Schmitz P. Schönmeier M. Schulte-Wissermann W. Schroeder T. Sefzick F. Stinzing G.Y. Sun G.J. Wagner M. Wagner A. Wilms P. Wintz S. Wirth P. Zupranski 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):127-137
The reaction pp → ppη was measured at excess energies of 15 and 41 MeV at an external target of the Jülich Cooler Synchrotron COSY with the time-of-flight
spectrometer. About 25000 events were measured for the excess energy of 15 MeV and about 8000 for 41 MeV. Both protons of
the process ppη were detected with an acceptance of nearly 100% and the η was reconstructed by the missing-mass technique. For both excess
energies the angular distributions are found to be nearly isotropic. In the invariant-mass distributions strong deviations
from the pure phase space distributions are seen.
Received: 24 May 2002 / Accepted: 20 September 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: e.roderburg@fz-juelich.de
Communicated by M. Gar?on 相似文献
4.
G. Stenuit S. Michotte J. Govaerts L. Piraux 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(1):103-107
Theoretical and experimental magnetizations of lead nanowire arrays well below the superconducting transition temperature
Tc are described. The magnetic response of the array was investigated with a SQUID magnetometer. Hysteretic behaviour and phase
transitions have been observed in sweeping up and down the external magnetic field at different temperatures. The Meissner
and Abrikosov states were also experimentally observed in this apparently type-I superconductor. This fact brings to the fore
the non-trivial behaviour of the critical boundary κ
c ( = 1/ in bulk materials) between type-I and type-II phase transitions at mesoscopic scales. The time-independent Ginzburg-Landau
equations particularized to cylindrically symmetric configurations enable one to explain and reproduce the experimental magnetization
curves within 10% of error.
Received 16 January 2003 / Received in final form 27 March 2003 Published online 23 May 2003
RID="a"
ID="a"e-mail: stenuit@fynu.ucl.ac.be 相似文献
5.
The $-game 总被引:1,自引:0,他引:1
J. Vitting Andersen D. Sornette 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,31(1):141-145
We propose a payoff function extending Minority Games (MG) that captures the competition between agents to make money. In
contrast with previous MG, the best strategies are not always targeting the minority but are shifting opportunistically between
the minority and the majority. The emergent properties of the price dynamics and of the wealth of agents are strikingly different
from those found in MG. As the memory of agents is increased, we find a phase transition between a self-sustained speculative
phase in which a “stubborn majority” of agents effectively collaborate to arbitrage a market-maker for their mutual benefit
and a phase where the market-maker always arbitrages the agents. A subset of agents exhibit a sustained non-equilibrium risk-return
profile.
Received 5 June 2002 / Received in final form 21 November 2002 Published online 27 January 2003
RID="a"
ID="a"e-mail: sornette@unice.fr
RID="b"
ID="b"CNRS UMR7536
RID="c"
ID="c"CNRS UMR6622 相似文献
6.
L.L. Salcedo 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):71-94
The multiscattering problem is studied in the matrix density formalism. We study how to isolate the quasi-classical degrees
of freedom in order to connect them with a cascade approach. The different problems that arise, as well as their possible
solutions, are discussed and exemplified with a pion-nucleus model.
Received: 24 May 2002 / Accepted: 25 July 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: salcedo@ugr.es
Communicated by A. Sch?fer 相似文献
7.
G. De Smedt C. Godrèche J.M. Luck 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(2):215-225
We consider a ferromagnetic Ising chain evolving under Kawasaki dynamics at zero temperature. We investigate the statistics
of the blocking time, as well as various characteristics of the metastable configurations reached by the system, including
the statistics of the final energy, the spin correlations, and the distribution of domain sizes. Results of extensive numerical
simulations are compared with analytical predictions made for the a priori ensemble of all blocked configurations with equal weights. Qualitative differences are found, e.g. in the domain sizes, which are found to be neither statistically independent nor exponentially distributed.
Received 24 October 2002 / Received in final form 13 January 2003 Published online 1st April 2003
RID="a"
ID="a"e-mail: luck@spht.saclay.cea.fr
RID="b"
ID="b"URA 2306 of CNRS 相似文献
8.
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
9.
W. Melnitchouk 《The European Physical Journal A - Hadrons and Nuclei》2003,17(2):223-234
We explore the relationship between exclusive and inclusive electromagnetic scattering from the pion, focusing on the transition
region at intermediate Q2. Combining Drell-Yan data on the leading twist quark distribution in the pion with a model for the resonance region at large
x, we calculate QCD moments of the pion structure function over a range of Q2, and quantify the role of higher twist corrections. Using a parameterization of the pion elastic form factor and phenomenological
models for the π↦ρ transition form factor, we further test the extent to which local duality may be valid for the pion.
Received: 10 February 2003 / Accepted: 12 March 2003 / Published online: 27 May 2003 相似文献
10.
An approach is proposed to calculate Generalized Parton Distributions (GPDs) in a Constituent Quark Model (CQM) scenario.
These off-diagonal distributions are obtained from momentum space wave functions to be evaluated in a given non-relativistic
or relativized CQM. The general relations linking the twist-two GPDs to the form factors and to the leading-twist quark densities
are consistently recovered from our expressions. Results for the leading twist, unpolarized GPD, H, in a simple harmonic-oscillator model, as well as in the Isgur and Karl model, are shown to have the general behavior found
in previous estimates. NLO evolution of the obtained distributions, from the low-momentum scale of the model up to the experimental
one, is also shown. Further applications of the proposed formalism are addressed.
Received: 31 January 2002 / Accepted: 25 November 2002 / Published online: 18 March 2003
RID="a"
ID="a"e-mail: sergio.scopetta@pg.infn.it
RID="b"
ID="b"e-mail: vicente.vento@uv.es
Communicated by A. Sch?fer 相似文献
11.
W.M. Alberico F. Giacosa M. Nardi C. Ratti 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):221-228
We employ the Nambu-Jona-Lasinio model to determine the vacuum pressure on the quarks in a baryon and hence their density
inside. Then we estimate the baryonic masses by implementing the local density approximation for the mean-field quark energies
obtained in a uniform and isotropic system. We obtain a fair agreement with the experimental masses.
Received: 27 September 2002 / Accepted: 4 October 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: giacosa@tphys.physik.uni-tuebingen.de
Communicated by A. Molinari 相似文献
12.
U.T. Yakhshiev U.-G. Meißner A. Wirzba 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):569-574
We investigate the possible modifications of the nucleons' electromagnetic form factors in the framework of a modified Skyrme
model allowing for nucleon deformation and using realistic nuclear mass distributions. We show that such effects are small
in light nuclei
Received: 19 November 2002 / Accepted: 3 December 2002 / Published online: 18 March 2003
RID="a"
ID="a"Address after January 1st, 2003: Helmholtz Institut für Strahlen- und Kernphysik (Theorie), Universit?t Bonn, Nu?allee
14-16, D-53115 Bonn, Germany; e-mail: meissner@itkp.uni-bonn.de
RID="b"
ID="b"Present address: Helmholtz Institut für Strahlen- und Kernphysik (Theorie), Universit?t Bonn, D-53115 Bonn, Germany.
Communicated by V. Vento 相似文献
13.
A disclination line populated with point defects that break the translational symmetry forms near a free nematic (N) interface
in a confined geometry. The disclination line is, however, absent in the smectic-A phase (SmA). We use this fact to control
the formation of point defect distributions on a disclination line by directional melting of the SmA phase in a temperature
gradient. A threshold velocity ( v
th) exists below which a defect-free disclination line is formed. The frequency of nucleation of point defects increases steadily
for v > v
th and exhibits a remarkable regularity. We derive an empirical scaling for v
th in terms of the experimental tuning parameters. We propose a simple model that allows to understand the formation of the
point defects.
Received 1 October 2002 / Published online: 15 April 2003
RID="a"
ID="a"Permanent address: Departament de Quımica Fısica, Universitat de Barcelona, Martı i Franquès 1, Barcelona 08028, Spain; e-mail: jignes@qf.ub.es 相似文献
14.
We study anomalous J/Ψ suppression and p
t broadening in the model of prompt gluons. The anomalous suppression can be successfully described in this model. The transverse-momentum
dependence of J/Ψ suppression in relativistic heavy-ion collisions is calculated from initial-state gluon rescattering with both nucleons
and prompt gluons produced in nucleon-nucleon collisions in the early phase of the reaction. It seems impossible to describe
simultaneously anomalous suppression and p
t broadening in Pb-Pb collisions within the model of prompt gluons with reasonable values of the parameters.
Received: 27 September 2001 / Accepted: 12 November 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: zhuangpf@mail.singhua.edu.cn
Communicated by A. Molinari 相似文献
15.
We study the lateral and transverse diffusion of amphiphiles in two-component bilayer membranes, using a coarse-grained model
for amphiphilic molecules and combined Monte Carlo-Molecular Dynamics simulations. Membrane structural properties, such as
the mean thickness, are also measured. The dependence of such properties on membrane composition, inter-molecular interactions,
and amphiphile stiffness is determined. In particular, we show that addition of shorter amphiphiles drives the model membrane
towards a more fluid state, with increased amphiphile lateral diffusion rates. These results can be understood in the framework
of a simple free-volume model. Furthermore, we observe an increase in the trans-membrane diffusion when the interaction energy
of amphiphiles with their neighboring molecules is decreased.
Received: 6 December 2002 / Accepted: 17 April 2003 / Published online: 27 May 2003
RID="a"
ID="a"e-mail: imparato@mpikg-golm.mpg.de
RID="b"
ID="b"e-mail: shillcock@mpikg-golm.mpg.de
RID="c"
ID="c"e-mail: lipowsky@mpikg-golm.mpg.de 相似文献
16.
Verneuil E Clain J Buguin A Brochard-Wyart F 《The European physical journal. E, Soft matter》2003,10(4):345-353
A soft bead (radius R
b) is pressed with a force F against a hydrophobic glass plate through a water drop (“wet” JKR set-up). We observe with a fast camera the growth of the
contact zone bridging the rubber bead to the glass. Depending on the approach velocity V, two regimes are observed : i) at large V a liquid film is squeezed at the interface and dewets by nucleation and growth of a dry contact; ii) at low velocities, the
bead remains nearly spherical. As it comes into contact, the rubber bead spreads on the glass with a characteristic time (in
the range of one millisecond) τ ≈ ηR
b
2/F, where η is the liquid viscosity. The laws of spreading are interpreted by a balance of global mechanical and viscous forces.
Received: 22 December 2002 / Accepted: 24 March 2003 / Published online: 29 April 2003
RID="a"
ID="a"e-mail: brochard@curie.fr 相似文献
17.
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
18.
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
19.
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
20.
We present an extensive experimental study and scaling analysis of friction of gelatin gels on glass. At low driving velocities,
sliding occurs via propagation of periodic self-healing slip pulses whose velocity is limited by collective diffusion of the
gel network. Healing can be attributed to a frictional instability occurring at the slip velocity V = V
c. For V > V
c, sliding is homogeneous and friction is ruled by the shear-thinning rheology of an interfacial layer of thickness of order
the (nanometric) mesh size, containing a solution of polymer chain ends hanging from the network. In spite of its high degree
of confinement, the rheology of this system does not differ qualitatively from known bulk ones. The observed ageing of the
static friction threshold reveals the slow increase of adhesive bonding between chain ends and glass. Such structural ageing
is compatible with the existence of a velocity-weakening regime at velocities smaller than V
c, hence with the existence of the healing instability.
Received: 7 March 2003 / Accepted: 2 May 2003 / Published online: 11 June 2003
RID="b"
ID="b"e-mail: ronsin@gps.jussieu.fr 相似文献