共查询到20条相似文献,搜索用时 15 毫秒
1.
E. Hatta D. Suzuki J. Nagao 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(4):609-614
The morphology on collapsed monolayers at the air-water interface has been studied using phase contrast microscopy. It is
found that the transition from randomly distributed to quasi-one dimensional crack pattern takes place, depending on the pH
value of the subphase and the presence of specific divalent metal ions. In these macroscopic patterns, the former exhibits
a surface roughening due to a monolayer buckling while the latter becomes more smooth and uniform. The occurrence of the former
is instantaneous and the latter follows a slow dynamics, i.e., the crack propagation in monolayers occurs with a delay for crack nucleation. Thus the change of pattern indicates the existence
of a dynamic transition. The transition is discussed with the scenario of a crack instability in brittle materials. The changes
of viscous nature and of ion binding, and the compression direction probably operate for the observed behavior effectively.
Received 11 January 1999 相似文献
2.
A. Guarino A. Garcimartín S. Ciliberto 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(1):13-24
The statistical properties and the localization of fracture precursors on heteregeneous materials is studied by recording
their acoustic emission as a function of the applied load. It's found that the microcrack cluster together as the load increases
and the instantaneous acoustic energy has an invariant power law distribution. The integrated acoustic energy presents a critical
divergency close to the failure load for the sample. These result support the idea that fracture can be viewed as a critical
phenomenon. Finally a measure of the concentration of microcraks, which allows us to predict the failure load, is introduced.
These properties are studied also when a periodic load is applied to the sample. It's found that the Kaiser effect is not
strictly satisfied in heteregeneous materials.
Received: 23 January 1998 / Revised: 20 April 1998 / Accepted: 17 June 1998 相似文献
3.
V. N. Kondratyev Ph. Blanchard H. O. Lutz 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,8(2):241-244
The multi-fragmentation dynamics of noble gas atomic clusters is considered for different statistically distributed deposited
energies. The conditions giving rise to the development of criticality in the cluster evolution are revealed from an analysis
of the signals in the fragment mass distribution. The time dependence of the observables related to critical exponents is
studied. It is demonstrated that in a certain regime the cluster exhibits a behavior which can be identified as the precursor
of a second-order liquid-gas phase transition.
Received 1st September 1998 and Received in final form 14 January 1999 相似文献
4.
K. Ivanova 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(2):327-330
The two-dimensional Ausloos et al. model of fluid invasion, freezing and thawing in a porous medium is elaborated upon and investigated in order to take into
account the pore volume redistribution and conservation during freezing. The results are qualitatively different from previous
work, since the damaged pore sizes are found to be much less than the possible maximum value and is reached after a large
number of invasion-freezing-thawing cycles, e.g. the material is “slowly damaged”. The pore size distribution is thus found in better agreement with expected practical findings.
The successive invasion percolation clusters are still found to be self-avoiding with aging. The cluster size decreases with
a power law as a function of invasion-frost-thaw iterations. The aging kinetics is also discussed through the normalized totally
invaded pore volume.
Received 24 September 1999 and Received in final form 5 January 2000 相似文献
5.
Y. Kuramoto 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(3):457-464
The poor man's scaling is extended to higher order by the use of the open-shell Rayleigh-Schr?dinger perturbation theory.
A generalized Kondo-type model with the SU(n)SU(m) symmetry is proposed and renormalized to the third order. It is shown that the model has both local Fermi-liquid and non-Fermi-liquid
fixed points, and that the latter becomes unstable in the special case of n=m=2. Possible relevance of the model to the newly found phase IV in CexLa1-xB6 is discussed.
Received: 24 February 1998 / Accepted: 17 April 1998 相似文献
6.
A general theory of critical sound propagation, including phonon-spin-energy coupling, is studied in anisotropic magnets above
their transition temperature. The Kawasaki weak singularity in the ultrasonic attenuation is found as a nonasymptotic effect.
A new nonasymptotic regime similar to the one in the binary mixture is also determined. The role of coupling constants and
the bare relaxation times in establishing the dominance region of particular terms, is discussed.
Received: 9 December 1997 / Accepted: 24 February 1998 相似文献
7.
D. Sornette J.V. Andersen 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,1(3):353-357
We revisit a simple dynamical model of rupture in random media with long-range elasticity to test whether rupture can be seen
as a first-order or a critical transition. We find a clear scaling of the macroscopic modulus as a function of time-to-rupture
and of the amplitude of the disorder, which allows us to collapse neatly the numerical simulations over more than five decades
in time and more than one decade in disorder amplitude onto a single master curve. We thus conclude that, at least in this
model, dynamical rupture in systems with long-range elasticity is a genuine critical phenomenon occurring as soon as the disorder
is non-vanishing.
Received: 11 July 1997 / Revised: 6 November 1997 / Accepted: 10 November 1997 相似文献
8.
9.
X.S. Chen V. Dohm D. Stauffer 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(4):699-704
Using field theory and Monte Carlo (MC) simulation we investigate the finite-size effects of the magnetization M for the three-dimensional Ising model in a finite cubic geometry with periodic boundary conditions. The field theory with
infinite cutoff gives a scaling form of the equation of state where is the reduced temperature, h is the external field and L is the size of system. Below and at the theory predicts a nonmonotonic dependence of f(x,y) with respect to at fixed and a crossover from nonmonotonic to monotonic behaviour when y is further increased. These results are confirmed by MC simulation. The scaling function f(x,y) obtained from the field theory is in good quantitative agreement with the finite-size MC data. Good agreement is also found
for the bulk value at .
Received 20 July 1999 and Received in final form 11 November 1999 相似文献
10.
H. Chamati D.M. Danchev N.S. Tonchev 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(2):307-316
A d-dimensional quantum model system confined to a general hypercubical geometry with linear spatial size L and “temporal size” 1/T ( T - temperature of the system) is considered in the spherical approximation under periodic boundary conditions. For a film
geometry in different space dimensions , where is a parameter controlling the decay of the long-range interaction, the free energy and the Casimir amplitudes are given.
We have proven that, if , the Casimir amplitude of the model, characterizing the leading temperature corrections to its ground state, is . The last implies that the universal constant of the model remains the same for both short, as well as long-range interactions, if one takes the normalization factor for
the Gaussian model to be such that . This is a generalization to the case of long-range interaction of the well-known result due to Sachdev. That constant differs
from the corresponding one characterizing the leading finite-size corrections at zero temperature which for is .
Received 3 June 1999 and Received in final form 16 August 1999 相似文献
11.
X.S. Chen V. Dohm 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,10(4):687-703
We reexamine the range of validity of finite-size scaling in the lattice model and the field theory below four dimensions. We show that general renormalization-group arguments based on the renormalizability of
the theory do not rule out the possibility of a violation of finite-size scaling due to a finite lattice constant and a finite
cutoff. For a confined geometry of linear size L with periodic boundary conditions we analyze the approach towards bulk critical behavior as at fixed for where is the bulk correlation length. We show that for this analysis ordinary renormalized perturbation theory is sufficient. On
the basis of one-loop results and of exact results in the spherical limit we find that finite-size scaling is violated for
both the lattice model and the field theory in the region . The non-scaling effects in the field theory and in the lattice model differ significantly from each other.
Received 5 February 1999 相似文献
12.
The dynamics of intermittent granular flow through an orifice at the bottom of a granular bin and the associated clogging
due to formation of arches blocking the outlet, is studied numerically in two dimensions. When the hole size is less than
the grain diameter, only a single grain is removed from the system so that the system self-organizes to a steady state and
the distribution of the grain displacements decays as power laws. On the other hand, when hole sizes are within few times
of the grain diameter, the outflow distributions are also observed to follow a power law.
Received 21 July 1999 and Received in final form 17 September 1999 相似文献
13.
K. Schenk B. Drossel S. Clar F. Schwabl 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(1):177-185
We study finite-size effects in the self-organized critical forest-fire model by numerically evaluating the tree density and
the fire size distribution. The results show that this model does not display the finite-size scaling seen in conventional
critical systems. Rather, the system is composed of relatively homogeneous patches of different tree densities, leading to
two qualitatively different types of fires: those that span an entire patch and those that do not. As the system size becomes
smaller, the system contains less patches, and finally becomes homogeneous, with large density fluctuations in time.
Received 24 April 1999 and Received in final form 26 October 1999 相似文献
14.
M. Kaulke I. Peschel 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(3):727-734
The spin one-half Heisenberg chain with U
q
[
SU
(2)] symmetry is studied via density-matrix renormalization. Ground-state energy and q-symmetric correlation functions are calculated for the non-Hermitian case with integer r. This gives bulk and surface exponents for (para)fermionic correlations in the related Ising and Potts models. The case of
real q corresponding to a diffusion problem is treated analytically.
Received: 18 February 1998 / Accepted: 17 March 1998 相似文献
15.
B.M. Roehner D. Sornette 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,4(3):387-399
We find empirically a characteristic sharp peak-flat trough pattern in a large set of commodity prices. We argue that the
sharp peak structure reflects an endogenous inter-market organization, and that peaks may be seen as local “singularities”
resulting from imitation and herding. These findings impose a novel stringent constraint on the construction of models.
Received: 2 February 1998 / Revised and accepted: 22 February 1998 相似文献
16.
A. Hansen M.H. Jensen K. Sneppen G. Zocchi 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,10(1):193-196
We argue that the first order hot and cold folding transitions of proteins observed at physiological chemical conditions ends
in a critical point at a given temperature and chemical potential of the surrounding water. We investigate the properties
of this critical point using a single-pathway scenario for the folding process. This pathway assumption determines the form
of a Hamiltonian whose critical properties define a new universality class.
Received 9 November 1998 相似文献
17.
A.F.S. Moreira W. Figueiredo V.B. Henriques 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,27(1):153-159
We performed a detailed Landau expansion of the free energy for a metamagnetic model considering terms up to twelfth order.
We obtained explicit expressions for the coefficients as a function of the temperature and the ratio between ferro- and antiferromagnetic
interactions. We showed that a naive analysis based on the signs of these coefficients cannot always give us sufficient guarantee
about the correctness of the phase diagram of the model. In these cases it is necessary to resort to the full expression of
the free energy in order to characterize the nature of the phase transition.
Received 28 November 2001 相似文献
18.
B. Dubrulle 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(4):757-771
We develop a new approach to scale symmetry, which takes into account the possible finite cut-offs of the fields or the parameters.
This new symmetry, called finite size scale symmetry: i) includes the traditional self-similarity as a limiting case, when
the cut-offs are set to infinity (infinite size-system); ii) is consistent with the traditional finite size scaling approach
already used in critical phenomena; iii) enables the computation of some of the universal functions appearing in the finite
size scaling formulation; iv) allows scale transformations leaving the cut-offs invariant, like in the traditional renormalization
approach; v) can be formulated to allow for positive or negative fields and parameters; vi) leads to new predictions about
the shape of some distributions in critical phenomena or turbulence which are in very good agreement with the experimental
or numerical findings.
Received 26 January 1999 and Received in final form 25 October 1999 相似文献
19.
X. X. Yi H. Wang W. Wang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):355-362
We present a theory to establish a relation between Hahn
spin-echo of a spin-1/2 particle and quantum phase
transitions in many-body systems. The Hahn echo is calculated and
discussed at zero as well as at finite temperatures. On the
example of XY model, we show that the critical points of the chain
are marked by the extremal values in the Hahn echo, and can
influence the Hahn echo in finite temperatures. An explanation for
the relation between the echo and criticality is also presented. 相似文献
20.
M.T. Batchelor K.A. Seaton 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(3):719-725
On the basis of features observed in the exact perturbation approach solution for the eigenspectrum of the dilute A3 model, we propose expressions for excitations in the dilute A4 and A6 models. Principally, we require that these expressions satisfy the appropriate inversion relations. We demonstrate that they
give the expected E7 and E6 mass spectra, and universal amplitudes, and agree with numerical expressions for the eigenvalues.
Received: 17 February 1998 / Accepted: 30 April 1998 相似文献