排序方式: 共有82条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
We investigate steady granular surface flows in a rotating drum and demonstrate the existence of rigid clusters of grains embedded in the flowing layer. These clusters appear to be fractal and their size is power law distributed from the grain size scale up to the thickness of the flowing layer. The implications of the absence of a characteristic length scale on available theoretical models of dense granular flows are discussed. Finally, we suggest a possible explanation of the difference between velocity profiles observed in surface flows and in flows down a rough inclined plane. 相似文献
6.
M. Sasaki V. Dupuis J.-P. Bouchaud E. Vincent 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(3):469-479
We study the deviations from perfect memory in negative temperature cycle spin glass experiments. It is known that the a.c.
susceptibility after the temperature is raised back to its initial value is superimposed to the reference isothermal curve
for large enough temperature jumps ΔT (perfect memory). For smaller ΔT, the deviation from this perfect memory has a striking non monotonous behavior: the `memory anomaly' is negative for small ΔT's, becomes positive for intermediate ΔT's, before vanishing for still larger ΔT's. We show that this interesting behavior can be reproduced by simple Random Energy trap models. We discuss an alternative
interpretation in terms of droplets and temperature chaos.
Received 23 May 2002 Published online 14 October 2002
RID="a"
ID="a"e-mail: sasaki@ipno.in2p3.fr 相似文献
7.
Célarié F Prades S Bonamy D Ferrero L Bouchaud E Guillot C Marlière C 《Physical review letters》2003,90(7):075504
We report in situ atomic force microscopy experiments which reveal the presence of nanoscale damage cavities ahead of a stress-corrosion crack tip in glass. Their presence might explain the departure from linear elasticity observed in the vicinity of a crack tip in glass. Such a ductile fracture mechanism, widely observed in the case of metallic materials at the micrometer scale, might be also at the origin of the striking similarity of the morphologies of fracture surfaces of glass and metallic alloys at different length scales. 相似文献
8.
In this paper, we review several important features of the out-of-equilibrium dynamics of spin glasses. Starting with the
simplest experiments, we discuss the scaling laws used to describe the isothermal aging observed in spin glasses after a quench
down to the low-temperature phase. We report in particular new results on the sub-aging behaviour of spin glasses. We then
discuss the rejuvenation and memory effects observed when a spin glass is submitted to temperature variations during aging,
from the point of view of both energy landscape pictures and real-space pictures. We highlight the fact that both approaches
point out the necessity of hierarchical processes involved in aging. Finally, we report an investigation of the effect of
small temperature variations on aging in spin glass samples with various anisotropies which indicates that this hierarchy
depends on the spin anisotropy. 相似文献
9.
We show that the inclusion of the (gapless) center-of-mass motion together with a functional integral representation of the Bethe wave function allows one to predict exactly the critical exponents for random directed polymers in (1+1) dimensions. The corresponding amplitudes are computed; they compare satisfactorily with existing numerical data. Within a replica-symmetric theory, we find that the Green function of the polymer has the form recently proposed by Parisi. 相似文献
10.
If we observe a line drawn on any background through a cylindrical lens, it becomes practically invisible provided it is parallel to the axis of the cylinder. When the line is perpendicular to this direction, its remains perfectly contrasted. Using this simple principle, lines of any arbitrary direction can be filtered by suitable rotation of the lens or any other astigmatic system. Experiments have also been carried out with completely incoherent light. 相似文献