摘要:

The critical behavior and the crossover scaling of self‐avoiding walks on a percolation cluster embedded in four‐dimensional hypercubic lattices were investigated by Monte Carlo simulations. Results obtained appear to suggest a crossover to a new universality class at percolation threshold.

ISSN:0094-243X    

DOI:10.1063/1.42432

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Among the great deal of models aiming to describe the origins of the ‘‘pathological’’ dynamical properties of disordered systems none of them starts from a realistic description of the actual properties of these systems at an atomic level. In fact we show here that this very nature has a strong influence on the global characteristics. In particular the meaning of the macroscopic properties is not simply linked with pertinent parameters at an atomic level.

ISSN:0094-243X    

DOI:10.1063/1.42380

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

The kinetic analyses and computer simulations were carried out on the pattern formation in phase transitions of the alloys, in which three different types of order parameters are involved; the one is the composition, and the other two sare the B2 and DO3types of order. Three different cases were investigated; one is an isotropic phase transition from A2 to A2+DO3, observed in Fe3Al, another is an anisotropic transition from B2 to B2+DO3, observed in Fe‐Si, and the third is a simple ordering from B2 to DO3, also observed in Fe‐Si, and the third is a simple ordering from B2 to DO3, also observed in Fe3Al. The results of our kinetic investigation turned out consistent with the observations.

ISSN:0094-243X    

DOI:10.1063/1.42381

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

We study the growth (‘‘coarsening’’) of domains following a quench in an Ising model with weak next‐nearest‐neighbor antiferromagnetic (AFM) bonds and single‐spin‐flip dynamics. The AFM bonds introduce free energy barriers to coarsening and thus greatly slow the dynamics. In three dimensions, simple physical arguments suggest that the barriers are proportional to the characteristic length scaleL(t) for quenches below the corner rounding transition temperatureTCR. This should leadL(t)∼log(t) at long timest. Monte Carlo simulations provide strong support for this claim.We also predict logarithmic growth in a purely two‐dimensional tiling model, which can be thought of as describing a single interface in our three‐dimensional model viewed from the direction. Here, the slow coarsening dynamics should persist all the way up to the order‐disorder transition (atTCR). However, if the model is cooled slowly at a rate &Ggr;, the final length scale should have power‐law, not logarithmic, dependence of 1/&Ggr;. Simulations support both of these claims.

ISSN:0094-243X    

DOI:10.1063/1.42383

出版商:AIP    

年代:1992

数据来源: AIP

ISSN:0094-243X    

DOI:10.1063/1.42384

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Effect of a uniform flow on the dynamics and the structure of growing patterns in a diffusion field is studied theoretically, and the resulting predictions are confirmed by the Monte Carlo simulation of a lattice gas system.

ISSN:0094-243X    

DOI:10.1063/1.42385

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Metastable free energies obtained from numerical transfer‐matrix calculations yield scaling results in reasonable agreement with field‐theoetical predictions.

ISSN:0094-243X    

DOI:10.1063/1.42386

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

Rheological properties of foams which have two‐dimensional random cellular structures are studied by computer simulations of vertex models. The simulations are performed under simple shear flow for small shear rates. Through these computer simulations, existence of the yield stress and the shear rate dependence of shear stress are investigated.

ISSN:0094-243X    

DOI:10.1063/1.42387

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

New scaling laws are obtained for the Ostwald ripening in a open cell where the total amount of both the solute and the precipitates flows out into the neighboring cell.

ISSN:0094-243X    

DOI:10.1063/1.42388

出版商:AIP    

年代:1992

数据来源: AIP

摘要:

In order to understand characteristic feature of relaxation dynamics of the phasons in quasicrystals, we investigate two‐dimensional Penrose tiling by a computer simulation. A power law behavior is found in relaxation of the quenched phason fluctuations at low temperatures.

ISSN:0094-243X    

DOI:10.1063/1.42389

出版商:AIP    

年代:1992

数据来源: AIP