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61.
Yu. A. Kashlev 《Theoretical and Mathematical Physics》2005,145(2):1590-1603
The classical diffusion theory cannot explain the temperature kink of the activation energy and the anomalous isotopic effect
observed in the hydrogen atom migration in BCC metals. We present a theory based on the equations of quantum statistical mechanics
that permits interpreting both these phenomena completely. We consider three possible mechanisms for an elementary act of
hydrogen diffusion in metals: the over-barrier hopping, the thermally activated tunnel transition, and the tunneling due to
decay of a local deformation near the hydrogen atom.
__________
Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 145, No. 2, pp. 256–271, November, 2005. 相似文献
62.
The effect of long-range forces on the dynamics of a bar 总被引:2,自引:0,他引:2
Olaf Weckner 《Journal of the mechanics and physics of solids》2005,53(3):705-728
The one-dimensional dynamic response of an infinite bar composed of a linear “microelastic material” is examined. The principal physical characteristic of this constitutive model is that it accounts for the effects of long-range forces. The general theory that describes our setting, including the accompanying equation of motion, was developed independently by Kunin (Elastic Media with Microstructure I, 1982), Rogula (Nonlocal Theory of Material Media, 1982) and Silling (J. Mech. Phys. Solids 48 (2000) 175), and is called the peridynamic theory. The general initial-value problem is solved and the motion is found to be dispersive as a consequence of the long-range forces. The result converges, in the limit of short-range forces, to the classical result for a linearly elastic medium. Explicit solutions in elementary form are given in a broad class of special cases. The most striking observations arise in the Riemann-like problem corresponding to a constant initial displacement field and a piecewise constant initial velocity field. Even though, initially, the displacement field is continuous, it involves a jump discontinuity for all later times, the Lagrangian location of which remains stationary. For some materials the magnitude of the discontinuity-jump oscillates about an average value, while for others it grows monotonically, presumably fracturing the material when it exceeds some critical level. 相似文献
63.
本文提出描述性抽样方法的实质,即利用更少的时间抽取更多的服从要求概率分布的样本点,讨论了该方法的计算步骤和适用范围,并将描述性抽样方法与重要抽样方法结合起来计算多变量多模式的结构失效概率,比较了描述性抽样方法与一般抽样法的方差,算例结果表明描述性抽样方法具有较好的收敛性. 相似文献
64.
65.
The resilient dissipative dynamic output feedback control problem for a class of uncertain Markov jump Lur’e systems with piecewise homogeneous transition probabilities and time-varying delays in the discrete-time domain are examined in this study. The designed controller can tolerate additive uncertainties in the controller gain matrix, which result from controller implementations. The time-varying delays are also supposed to be mode-dependent with lower and upper bounds known a priori. By constructing a Lyapunov–Krasovskii functional candidate, the sufficient conditions regarding the existence of desired resilient dissipative controllers are obtained in terms of linear matrix inequalities, thereby ensuring that the resulting closed-loop system is stochastically stable and strictly dissipative. Two numerical examples were established to illustrate the effectiveness of the proposed theoretical results. 相似文献
66.
In this paper, we extend the previous Markov-modulated
reflected Brownian motion model discussed in [1] to a Markov-modulated
reflected jump diffusion process, where the jump component is described as a
Markov-modulated compound Poisson process. We compute the joint stationary
distribution of the bivariate Markov jump process. An abstract example with two
states is given to illustrate how the stationary equation described as a system
of ordinary integro-differential equations is solved by choosing appropriate
boundary conditions. As a special case, we also give the sationary distribution
for this Markov jump process but without Markovian regime-switching. 相似文献
67.
In this paper, the asymptotic behavior of the weak solution (u_t)_{t\ge0} to the non-local Cauchy problems as stated in (1) is considered. Only using lower bounds of jumping kernel J(x,y) for large |x-y|, it is obtained that \|u_t\|_p\le c(t)\|u_0\|_q with any 1\le q
相似文献
68.
69.
70.
In this article, we establish the existence of the solution to the càdlàg perturbed Skorohod problem. As an application, we obtain the existence and uniqueness of the solution to the perturbed reflected jump diffusion processes. 相似文献