Temperature-dependent crack surface tension

The fracture surface energy is calculated for a one-dimensional, exactly solvable model of a crack. The temperature dependence of the crack surface tension is determined on the basis of a self-consistent Einstein approach. It is found that lattice vibrations result in a strong reduction in the crack surface tension.     

Target-mask shape congruence impacts the type of metacontrast masking

Visual metacontrast masking may depend on the time intervals between target and mask in two qualitatively different ways: in type-A masking the smaller the mask delay from target the stronger the masking while in type-B masking maximal masking effect is obtained with a larger temporal delay of the mask. Variability in the qualitative apperance of masking functions has been explained by variability in stimuli parameters and tasks. Recent research on metacontrast masking has surprisingly shown that both of these types of functions can be found with an identical range of stimulation parameters depending on individual differences between observers. Here we show that obtaining clear-cut type-A masking depends on whether target and mask shapes are congruent or incongruent and whether observers use the cues available due to the congruence factor. Conspicuously expressed type-A masking is selectively associated with incongruent target-mask pairings. In the latter conditions target identification level significantly drops with the shortest target-to-mask delays.     

Kinetics of Ostwald ripening in the presence of monomer diffusion along grain boundaries

The kinetics of an Ostwald ripening is studied where the prevailing mechanism of cluster growth is monomer diffusion along grain boundaries. The model describes self-consistently the situation when the delivery of matter to a growing cluster is carried out by monomer diffusion along grain boundaries. An analytical and numerical study of Ostwald ripening kinetics in a homogeneous supersaturated solution is performed. The possible transition modes arising during the Ostwald ripening process are discussed with reference to changes in the dominant monomer delivery mechanism.     

Kinetics of non-equilibrium step structure

The non-equilibrium structure of a [100]step on a (001) surface of a sc crystal is studied by introducing a new model in which densities of adatoms and vacancies on the step are treated as independent variables and the motion of kinks along the step is taken into account. The structural change of the step is found to be of a relaxational type with a relaxation time that is a function of temperature and degree of supersaturation. An approximate formula for the steady-state density of kinks for the case of low temperatures and low supersaturations is obtained.