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991.
M. Ibañes J. García-Ojalvo R. Toral J.M. Sancho 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,18(4):663-673
The domain growth processes originating from noise-induced nonequilibrium phase transitions are analyzed, both for non-conserved
and conserved dynamics. The existence of a dynamical scaling regime is established in the two cases, and the corresponding
growth laws are determined. The resulting universal dynamical scaling scenarios are those of Allen-Cahn and Lifshitz-Slyozov,
respectively. Additionally, the effect of noise sources on the behaviour of the pair correlation function at short distances
is studied.
Received 28 June 2000 and Received in final form 29 September 2000 相似文献
992.
N. Vandewalle S. Galam M. Kramer 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(3):407-410
Percolation and jamming phenomena are investigated for random sequential deposition of rectangular needles on d=2 square lattices. Associated thresholds and are determined for various needle sizes. Their ratios are found to be a constant for all sizes. In addition the ratio of jamming thresholds for respectively square blocks and needles is also found to be
a constant . These constants exhibit some universal connexion in the geometry of jamming and percolation for both anisotropic shapes
(needles versus square lattices) and isotropic shapes (square blocks on square lattices). A universal empirical law is proposed for all three
thresholds as a function of a.
Received 27 January 2000 and Received in final form 2 February 2000 相似文献
993.
V. Da Costa Y. Henry F. Bardou M. Romeo K. Ounadjela 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(2):297-303
Tiny spatial fluctuations of tunnel barrier parameters are shown to have dramatic consequences on the statistical properties
of quantum tunneling. A direct experimental evidence is provided that the tunnel current through metal-oxide junctions, imaged
at a nanometric scale, exhibits broad statistical distributions extending over more than 4 orders of magnitude. Striking effects
of broad current distributions are shown: the total tunnel transmission is dominated by few highly transmitting sites and
the typical current density varies strongly with the size of the junction. Moreover, self-averaging of the tunnel current
fluctuations occurs only for unexpectedly large junction areas.
Received 1 April 1999 相似文献
994.
F. Lillo R.N. Mantegna 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,15(4):603-606
We select the n stocks traded in the New York Stock Exchange and we form a statistical ensemble of daily stock returns for each of the k trading days of our database from the stock price time series. We study the ensemble return distribution for each trading
day and we find that the symmetry properties of the ensemble return distribution drastically change in crash and rally days
of the market. In crash and rally days, the distribution becomes asymmetric. In particular for crashes the positive tail is
steeper than the negative one whereas the reverse is observed in rally days.
Received 25 February 2000 相似文献
995.
A. Hazareesing J.-P. Bouchaud 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,14(4):713-724
We reconsider the problem of the static thermal roughening of an elastic manifold at the critical dimension d=2 in a periodic potential, using a perturbative Functional Renormalization Group approach. Our aim is to describe the effective
potential seen by the manifold below the roughening temperature on large length scales. We obtain analytically a flow equation
for the potential and surface tension of the manifold, valid for low temperatures. On a length scale L, the renormalized potential is made up of a succession of quasi parabolic wells, matching onto one another in a singular
region of width for large L. For strong periodic potential, the perturbation theory breaks down, and we argue, based on a variational calculation, that
the transition becomes first order. We also obtain numerically the step energy as a function of temperature, and relate our
results to the existing experimental data on 4He. Finally, we examine the case of a non local elasticity which is realized physically for the contact line.
Received 16 April 1999 and Received in final form 11 October 1999 相似文献
996.
The finite element method determining dynamic response of random structuressubjected to random dynamic load is studied,the formulas for dynamic response ofrandom structures and reliability based on random resistibility are proposed in thispaper. 相似文献
997.
我们引进了非线性随机算于的一般随机收缩概念,得到了非线性随机算于方程的解之存在性、唯一性及其近似的几个定理。改进和推广了[1~3)中的主要结果。 相似文献
998.
世界各国的学者对电子束的聚焦性能已经做了广泛的研究,提出了许多分析电子束聚焦性能的方法,在这些方法的基础上,试图利用概率分布函数来描述电子束的聚焦过程。该方法将电子的发射看做是随机过程,并从轨迹的落点的概率分析了电子束的形状和大小,避免了杂散小峰的影响。 相似文献
999.
混沌的抑制研究进展综述 总被引:7,自引:0,他引:7
综述了抑制混沌的4种主要方法:加随机噪声、加周期摄动、加动力吸振器和加输出变量反馈.概括了各种方法的一般形式,列举了各种方法应用的例子,还指出一些尚待研究的问题. 相似文献
1000.
王秀云 《浙江大学学报(理学版)》1998,25(2):15-18
本文给出了一随机游动所覆盖的最大圆盘R(n)的分布的一上尾估计, 由此将文献[ 5] 中的λ的取值范围从14 < λ<120 改进为14 < λ<8 . 相似文献