共查询到19条相似文献,搜索用时 93 毫秒
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为全面研究Wolf-Villain(WV)模型生长表面的统计性质,基于极值统计理论,模拟计算1+1维WV模型在饱和生长阶段表面的极大高度分布(maximal-height distribution,MAHD)和极小高度分布(minimal-height distribution,MIHD).结果表明,MAHD和MIHD在不同的系统尺寸下分别有较好的标度规律,这两个分布之间存在不对称性.其中,MAHD遵循-种常见的极值分布,即广义的Fisher-Tippett-Gumbel(FTG)型分布;而MIHD可以用-个修正的Fisher-Tippett-Gumbel(MFTG)型分布来描述. 相似文献
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为研究表面界面粗化生长中孔洞的标度行为,在对Ballistic Deposition(BD)模型进行数值模拟的基础上,对模型中孔洞的模拟生长情况进行统计和分析.结果表明,BD模型中孔洞数目随模型生长时间的变化从初始阶段的高于线性而渐趋近于线性,并对该规律进行理论分析. 相似文献
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采用Monte Carlo方法对3DX-Y模型进行数值模拟计算,研究了在非线性外场驱动下3DX-Y模 型的滞后标度和动态相变.得出了滞后标度关系为Area~hα0ωβ(1-T/Tc)γ, 其中α=0.57,β=0.34,γ=0.90.发现其动态相变行为在一定的临界参数条件下,初始短周 期(周期数PN≤10)内的结果具有与Ising模型类似的对称性破缺;但在长周期内(PN≥200)的 结果则明显区别于Ising模型而与Heisenberg模型相近,也即无稳定动态有序铁磁相的存在.
关键词:
X-Y模型
滞后标度
动态相变
Monte Carlo方法 相似文献
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采用Kinetic Monte Carlo方法对1+1维抛射沉积(BD)模型内部结构的动力学行为进行了大量的数值模拟研究.分别分析了空洞密度和内部界面的动力学行为.研究表明,空洞密度呈高斯型分布,其平均值首先随生长时间快速增长,然后达到一个与基底尺寸无关的饱和值.除表面宽度,还引入了新的极值统计方法来分析该模型内部界面的动力学行为,分析结果显示,1+1维BD模型内部界面的演化满足标准的Family-Vicsek标度规律,并且属Kardar-Parisi-Zhang方程所描述的普适类.最后对表面宽度和极值统计两种理论方法的有限尺寸效应进行了比较. 相似文献
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为探讨分形基底结构对生长表面标度行为的影响, 本文采用Kinetic Monte Carlo(KMC)方法模拟了刻蚀模型(etching model)在谢尔宾斯基箭头和蟹状分形基底上刻蚀表面的动力学行为. 研究表明,在两种分形基底上的刻蚀模型都表现出很好的动力学标度行为, 并且满足Family-Vicsek标度规律. 虽然谢尔宾斯基箭头和蟹状分形基底的分形维数相同, 但模拟得到的标度指数却不同, 并且粗糙度指数 α与动力学指数z也不满足在欧几里得基底上成立的标度关系α+z=2. 由此可以看出, 标度指数不仅与基底的分形维数有关, 而且和分形基底的具体结构有关. 相似文献
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采用Monte Carlo方法对离散混合经典Heisenberg自旋体系在周期性外场驱动下动态相变行为进行了模拟计算.在典型Heisenberg自旋体系的哈密顿量基础上,引入表征非晶相的随机各向异性能项(比例为X)和表征晶体相的单轴各向异性能项(比例为1-X),考察了该混合自旋体系磁滞后回线面积Aarea随X和单轴各向异性常数A及随机各向异性常数D的变化规律,并确定了该类自旋体系动态相变新的滞后标度关系Aarea-AδDη关键词:
海森堡模型
Monte Carlo模拟
磁滞标度
非晶纳米晶 相似文献
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表面界面动力学粗化过程是凝聚态物理领域重要的研究内容,为研究基底不完整性对刻蚀模型动力学 标度行为的影响,本文采用Kinetic Monte Carlo(KMC)方法,分析研究了在随机稀释基底上刻蚀模型(Etching model)生长表面的动力学标度行为.研究发现:尽管随机稀释基底的不完整性会对刻蚀表面的动力学 行为产生显著的影响,导致刻蚀表面粗糙度指数和生长指数有明显的增加, 但其仍基本满足原有的动力学标度规律.此外,本文还对刻蚀表面动力学标度指数的有限尺寸效应进行了 分析讨论. 相似文献
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为分析基底结构对离散生长模型动力学性质的影响, 本文在随机游走指数十分接近而分形维数和谱维数均不相同的科赫格子和科赫曲线分形基底上对受限固-固(restricted solid-on-solid)模型的生长过程进行数值模拟研究. 通过分析表面宽度和饱和表面极值高度的统计行为发现: 随机游走的动力学指数能够对饱和粗化表面的动力学行为起主要贡献. 尽管分形基底具有不同的分形维数和谱维数, 但是在两种分形基底上得到了在误差范围内相同的粗造度指数. 两种分形基底上饱和表面相对生长高度极大(小)值分布分别可以很好的塌缩在一起, 且很好的满足Asym2Sig函数分布. 相似文献
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WU Feng-Min XU You-Sheng LI Qiao-Wen 《理论物理通讯》2006,46(2):332-336
A comprehensive simulation model -- deposition, diffusion, rotation, reaction and aggregation model is presented to simulate the formation processes of ramified clusters on liquid surfaces, where clusters can disuse and rotate easily. The mobility (including diffusion and rotation) of clusters is related to its mass, which is given by Dm = Dos^-γD and θm = θos^-γθ, respectively. The influence of the reaction probability on the kinetics and structure formation is included in the simulation model. We concentrate on revealing dynamic scaling during ramified cluster formation. For this purpose, the time evolution of the cluster density and the weight-average cluster size as well as the cluster-size distribution scaling function at different time are determined for various conditions. The dependence of the cluster density on the deposition flux and time-dependence of fractal dimension are also investigated. The obtained results are helpful in understanding the formation of clusters or thin film growth on liquid surfaces. 相似文献
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WU Feng-Min XU You-Sheng LI Qiao-Wen 《理论物理通讯》2006,46(8)
A comprehensive simulation model -deposition,diffusion, rotation, reaction and aggregation model is presented to simulate the formation processes of ramified clusters on liquid surfaces, where clusters can diffuse and rotate easily. The mobility (including diffusion and rotation) of clusters is related to its mass, which is given by Dm = Dos-γD and θm =′θos-γθ, respectively. The influence of the reaction probability on the kinetics and structure formation is included in the simulation model. We concentrate on revealing dynamic scaling during ramified cluster formation. For this purpose, the time evolution of the cluster density and the weight-average cluster size as well as the cluster-size distribution scaling function at different time are determined for various conditions. The dependence of the cluster density on the deposition flux and time-dependence of fractal dimension are also investigated. The obtained results are helpful in understanding the formation of clusters or thin film growth on liquid surfaces. 相似文献
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Mound morphology of the 2+1 -dimensional Wolf-Villain model caused by the step-edge diffusion effect
The mound morphology of the 2+1-dimensional Wolf-Villain model is studied by numerical simulation. The diffusion rule of this model has an intrinsic mechanism, i.e., the step-edge diffusion, to create a local uphill particle current, which leads to the formation of the mound. In the simulation, a noise reduction technique is employed to enhance the local uphill particle current. Our results for the dynamic exponent 1/z and the roughness exponent α obtained from the surface width show a dependence on the strength of the step-edge diffusion. On the other hand, λ(t), which describes the separation of the mounds, grows as a function of time in a power-law form in the regime where the coalescence of mounds occurs, λ(t)∼tn, with n≈0.23-0.25 for a wide range of the deposition conditions under the step-edge diffusion effect. For m=1, a noise reduction factor of unity, the behavior of λ(t) in the saturated regime is also simulated. We find that the evolution behavior of λ(t) in the whole process can be described by the standard Family-Vicsek scaling. 相似文献
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The connection between anomalous scaling of structure functions (intermittency) and numerical methods for turbulence simulations
is discussed. It is argued that the computational work for direct numerical simulations (DNS) of fully developed turbulence
increases as Re
4, and not as Re
3 expected from Kolmogorov’s theory, where Re is a large-scale Reynolds number. Various relations for the moments of acceleration and velocity derivatives are derived.
An infinite set of exact constraints on dynamically consistent subgrid models for Large Eddy Simulations (LES) is derived
from the Navier–Stokes equations, and some problems of principle associated with existing LES models are highlighted 相似文献
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T. Ala-Nissila T. Hjelt J. M. Kosterlitz O. Venäläinen 《Journal of statistical physics》1993,72(1-2):207-225
We discuss the results of extensive numerical simulations in order to estimate the scaling exponents associated with kinetic roughening in higher dimensions, up tod=7 + l. To this end, we study the restricted solid-on-solid growth model, for which we employ a novel fitting ansatz for the spatially averaged height correlation function¯G(t)t
2 to estimate the scaling exponent. Using this method, we present a quantitative determination of ind=3 + 1 and 4+1 dimensions. To check the consistency of these results, we also compute the interface width and determine andx from it independently. Our results are in disagreement with all existing theories and conjectures, but in four dimensions they are in good agreement with recent simulations of Forrest and Tang for a different growth model. Above five dimensions, we use the time dependence of the width to obtain lower bound estimates for. Within the accuracy of our data, we find no indication of an upper critical dimension up tod = 7 + 1. 相似文献
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ZHANG Duan-Ming SUN Hong-Zhang LI Zhi-Hua PAN Gui-Jun YU Bo-Ming LI Rui YIN Yan-Ping 《理论物理通讯》2005,44(7)
The moment analysis is applied to perform large scale simulations of the rice-pile model. We find that this model shows different scaling behavior depending on the driving mechanism used. With the noisy driving, the rice-pile model violates the finite-size scaling hypothesis, whereas, with fixed driving, it shows well defined avalanche exponents and displays good finite size scaling behavior for the avalanche size and time duration distributions. 相似文献
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ZHANGDuan-Ming SUNHong-Zhang LIZhi-Hua PANGui-Jun YUBo-Ming LIRui YINYan-Ping 《理论物理通讯》2005,44(1):99-102
The moment analysis is applied to perform large scale simulations of the rice-pile model. We find that this model shows different scaling behavior depending on the driving mechanism used. With the noisy driving, the rice-pile model violates the finite-size scaling hypothesis, whereas, with fixed driving, it shows well defined avalanche exponents and displays good finite size scaling behavior for the avalanche size and time duration distributions. 相似文献