Explosive crystallization mechanism of ultradisperse amorphous films

The explosive crystallization of germanium ultradisperse amorphous films is studied experimentally. We show that crystallization may be initiated by local heating at the small film thickness but it realizes spontaneously at the large ones. The fractal pattern of the crystallized phase is discovered that is inherent in the phenomena of diffusion limited aggregation. It is shown that in contrast to the ordinary crystallization mode the explosive one is connected with the instability which is caused by the self-heating. A transition from the first mechanism to the second one is modelled by Lorenz system. The process of explosive crystallization is represented on the basis of the self-organized criticality conception. The front movement is described as the effective diffusion in the ultrametric space of hierarchically subordinated avalanches, corresponding to the explosive crystallization of elementary volumes of ultradisperse powder. The expressions for the stationary crystallization heat distribution and the steady-state heat current are obtained. The heat needed for initiation of the explosive crystallization is obtained as a function of the thermometric conductivity. The time dependence of the spontaneous crystallization probability in a thin films is examined.Comment: 22 pages, 5 figures, LaTe

Multifractal spectrum of phase space related to generalized thermostatistics

We consider a self-similar phase space with specific fractal dimension $d$ being distributed with spectrum function $f(d)$. Related thermostatistics is shown to be governed by the Tsallis formalism of the non-extensive statistics, where the non-additivity parameter is equal to ${\bar\tau}(q)\equiv 1/\tau(q)>1$, and the multifractal function $\tau(q)= qd_q-f(d_q)$ is the specific heat determined with multifractal parameter $q\in [1,\infty)$. In this way, the equipartition law is shown to take place. Optimization of the multifractal spectrum function $f(d)$ derives the relation between the statistical weight and the system complexity. It is shown the statistical weight exponent $\tau(q)$ can be modeled by hyperbolic tangent deformed in accordance with both Tsallis and Kaniadakis exponentials to describe arbitrary multifractal phase space explicitly. The spectrum function $f(d)$ is proved to increase monotonically from minimum value $f=-1$ at $d=0$ to maximum one $f=1$ at $d=1$. At the same time, the number of monofractals increases with growth of the phase space volume at small dimensions $d$ and falls down in the limit $d\to 1$.Comment: 16 pages, 7 figure

Self-organization of quasi-equilibrium stationary condensation in accumulative ion-plasma devices

We consider both theoretically and experimentally self-organization process of quasi-equilibrium steady-state condensation of sputtered substance in accumulative ion-plasma devices. The self-organization effect is shown to be caused by self-consistent variations of the condensate temperature and the supersaturation of depositing atoms. On the basis of the phase-plane method, we find two different types of the self-organization process to be possible. Experimental data related to aluminum condensates are discussed to confirm self-organization nature of quasi-equilibrium steady-state condensation process.Comment: 14 pages, 3 figure

Nonequilibrium phase transitions in stochastic systems with coloured fluctuations

We study the behaviour of a class of stochastic spatially extended systems exhibiting transition to absorbing configurations, reentrant noise induced phase transitions and phase transitions induced by noise crosscorrelations. We discuss the behaviour of the system in the presence of multiplicative fluctuations: a possibility of escaping from the absorbing state and the nature of disordered phase appearing beyond the second critical point of the reentrant phase transition. Making use of the mean field approach we have shown that noise cross-correlations lead to continuous, discontinuous and reentrant phase transitions

Embedding a Native State into a Random Heteropolymer Model: The Dynamic Approach

We study a random heteropolymer model with Langevin dynamics, in the supersymmetric formulation. Employing a procedure similar to one that has been used in static calculations, we construct an ensemble in which the affinity of the system for a native state is controlled by a "selection temperature" T0. In the limit of high T0, the model reduces to a random heteropolymer, while for T0-->0 the system is forced into the native state. Within the Gaussian variational approach that we employed previously for the random heteropolymer, we explore the phases of the system for large and small T0. For large T0, the system exhibits a (dynamical) spin glass phase, like that found for the random heteropolymer, below a temperature Tg. For small T0, we find an ordered phase, characterized by a nonzero overlap with the native state, below a temperature Tn \propto 1/T0 > Tg. However, the random-globule phase remains locally stable below Tn, down to the dynamical glass transition at Tg. Thus, in this model, folding is rapid for temperatures between Tg and Tn, but below Tg the system can get trapped in conformations uncorrelated with the native state. At a lower temperature, the ordered phase can also undergo a dynamical glass transition, splitting into substates separated by large barriers.Comment: 19 pages, revtex, 6 figure

Lifetime distributions in the methods of non-equilibrium statistical operator and superstatistics

A family of non-equilibrium statistical operators is introduced which differ by the system age distribution over which the quasi-equilibrium (relevant) distribution is averaged. To describe the nonequilibrium states of a system we introduce a new thermodynamic parameter - the lifetime of a system. Superstatistics, introduced in works of Beck and Cohen [Physica A \textbf{322}, (2003), 267] as fluctuating quantities of intensive thermodynamical parameters, are obtained from the statistical distribution of lifetime (random time to the system degeneracy) considered as a thermodynamical parameter. It is suggested to set the mixing distribution of the fluctuating parameter in the superstatistics theory in the form of the piecewise continuous functions. The distribution of lifetime in such systems has different form on the different stages of evolution of the system. The account of the past stages of the evolution of a system can have a substantial impact on the non-equilibrium behaviour of the system in a present time moment.Comment: 18 page

Statistical theory of self-similar time series

Within Tsallis statistics, a picture is elaborated to treat self-similar time series as a thermodynamic system. Thermodynamic-type characteristics relevant to temperature, pressure, entropy, internal and free energies are introduced and tested. Predictability conditions of time series analysis are discussed on the basis of Van der Waals model. Maximal magnitude for time interval and minimal resolution scale of the value under consideration are found and analyzed in details. Time series statistics is shown to be governed by effective temperature being exponential measure of the fractal dimensionality of a phase space related to the time series. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/137

Theory of hierarchical coupling

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