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11.
A.V. Barashev 《哲学杂志》2013,93(2):204-207
Evans's comments are related only loosely to the main body of our paper, which is devoted to the onset of void ordering: his Monte Carlo simulations of this early stage of ordering are in a qualitative agreement with our results. They question, however, the basic mechanisms of damage accumulation revealed by a number of scientists using various techniques over the years. Here we argue that his views are erroneous due to overlooking some essential features of one-dimensional defect transport. 相似文献
12.
Hcp-icosahedron structural transformation induced by the change in Ag concentration during the freezing of (CoAg)561 clusters 下载免费PDF全文
The synergy effect of alloy elements in bimetallic clusters can be used to tune the chemical and physical properties. Research on the influences of alloy concentration and distribution on the frozen structure of bimetallic clusters plays a key rolc in exploring new structural materials. In this paper, we study the influence of Ag concentration on the frozen structure of the (AgCo)561 cluster by using molecular dynamics simulation with a general embedded atom method. The results indicate that tt~e structure and chemical ordering of the (AgCo)561 cluster are strongly related to Ag concentration. Hcp-icosahedron structural transformation in the frozen (CoAg)561 cluster can be induced by changing Ag concentration. The chemical ordering also transforms to Janus-like Co Ag from core-shell Co-Ag. 相似文献
13.
The Young's modulus of graphene with various rectangular and circular vacancy defects is investigated by molecular dynamics simulation. By comparing with the results calculated from an effective spring model, it is demonstrated that the Young's modulus of graphene is largely correlated to the size of vacancy defects perpendicular to the stretching direction. And a linear reduction of Young's modulus with the increasing concentration of mono‐atomic‐vacancy defects (i.e., the slope of ?0.03) is also observed. The fracture behavior of graphene, including the fracture strength, crack initiation and propagation are then studied by the molecular dynamics simulation, the effective spring model, and the quantized fracture mechanics. The blunting effect of vacancy edges is demonstrated, and the characterized crack tip radius of 4.44 Å is observed. 相似文献
14.
Shigeru Shinomoto 《Journal of statistical physics》1983,32(1):105-113
It is found that the density expansion in the argument of the exponential function gives a fine convergence on the equation of state of the hard-sphere system. The pair distribution function and the equation of state is constructed by an intuitive kinetic theoretical method. The equation of state of the hard-core system with attractive potential is constructed semiempirically with the aid of this simple analytical result, and Kamerling-Onnes' constant of the critical point is obtained analytically. 相似文献
15.
Random walk properties and correlation factors for diffusion via the vacancy mechanism are calculated and compared for various three-dimensional lattices. By applying the theory of random walks on an imperfect lattice, the correlation factor for impurity diffusion is calculated rigorously for the five jump frequency model in the fee lattice.Presented at the Symposium on Random Walks, Gaithersburg, MD, June 1982. 相似文献
16.
二硫化钼纳米带按边界结构特征可分为锯齿型和扶手型,在制备过程中,不可避免地会存在一定的缺陷,其中硫空位(VS)最为常见,它将改变纳米结构,进而影响其电子性质。本文采用密度泛函理论来研究S空位对扶手型二硫化钼纳米带性质的影响。计算结果表明:纯扶手型二硫化钼纳米带(AMoS2NRs)为非磁性半导体,但其物性受S空位的位置及浓度所调制。当S空位出现在纳米带内部时,其性质不变。但当S空位在纳米带边缘时,AMoS2NRs被调节成半金属;并随着S空位的浓度的增加,其物性从半金属转变为稀磁半导体。这一有趣的发现将使得低维MoS2纳米材料在自旋电子学上有更宽广的应用。 相似文献
17.
基于13原子二十面体结构,采用密度泛函方法系统计算研究了Fe、Co及Ni单质及二元混合团簇的磁性.发现有限温度下团簇磁性随结构畸变的敏感性随Fe、Co、Ni顺序逐渐减弱,同时发现二十面体结构Fe_(13)及Co_(13)均具有不同磁矩的近简并低能态.对FeNi及CoNi混合团簇、其磁矩随组分的变化不存在反常现象,但对于FeCo混合团簇、其磁矩随组分的演化行为存在个别反常现象.我们认为:这种反常现象能够对FeCo非晶合金中的实验观测结果提供一种可能的理论解释. 相似文献
18.
D. Ferger 《Acta Appl Math》2003,78(1-3):115-120
We prove a functional law of the iterated logarithm for U-statistics type processes. The result is used to determine the almost sure set of limit points for change-point estimators. 相似文献
19.
Ivo Klik 《Journal of statistical physics》1991,62(1-2):389-397
The influence of the Bardeen-Herring back-jump correlations on the Fermi-Dirac statistics of the one-dimensional nonhomogeneous fermionic lattice gas is studied by the Monte Carlo simulation technique and semianalytically. The resulting distribution is obtained, exhibiting increased population of the lower levels in comparison to the Fermi-Dirac statistics. 相似文献
20.
As a model for a binary alloy undergoing an unmixing phase transition, we consider a square lattice where each site can be either taken by an A atom, a B atom, or a vacancy (V), and there exists a repulsive interaction between AB nearest neighbor pairs. Starting from a random initial configuration, unmixing proceeds via random jumps of A atoms or B atoms to nearest neighbor vacant sites. In the absence of any interaction, these jumps occur at jump rates
A and
B, respectively. For a small concentration of vacancies (c
v=0.04) the dynamics of the structure factorS(k,t) and its first two momentsk
1(t),k
2
2
(t) is studied during the early stages of phase separation, for several choices of concentrationc
B of B atoms. Forc
B=0.18 also the time evolution of the cluster size distribution is studied. Apart from very early times, the mean cluster sizel(t) as well as the moments of the structure function depend on timet and the ratio of the jump rates (=
B/
A) only via a scaled timet/(). Qualitatively, the behavior is very similar to the direct exchange model containing no vacancies. Consequences for phase separation of real alloys are briefly discussed. 相似文献