Experimental observation of the dislocation walls in heterostructures with two interfaces: Ge/Ge0.5Si0.5 10 nm/Si(001) as an example

High-resolution electron microscopy (HREM) at the atomic scale has been applied to study the edge dislocation redistribution between interfaces in Ge/Ge_0.5Si_0.5/Si(0?0?1) heterostructures. Our results provide a direct explanation that plastic relaxation of the GeSi buffer layer proceeds owing to motion of Lomer-type dislocation complexes consisting of a pair of complementary 60° dislocations with the ends of the {1?1?1} extra planes being located at a distance of ~2–12 interplanar spacings from each other. It is demonstrated that edge dislocations belonging to the upper and lower interfaces become arranged one under the other and dislocation walls are formed. The distributions of tension and compression in the [0?0?1] direction between two edge dislocations, obtained by processing the HREM image, testify to superposition of strain fields.     

Salvaging the Biological Design Argument in Light of Darwinism?

It is a common assumption that biological organisms appear as though they were designed. Prior to the Darwinian revolution, the order of biological organisms was often taken as a sign of their divine Creator. It is also commonly argued that Darwinian evolutionary theory as a good explanation for the adaptive complexity of biology reveals this appearance to be merely an illusion. However, in recent philosophical discussion several defenses of the compatibility of divine design and Darwinian evolution have emerged. These defenses insist not only that divine design and evolution are compatible, but even that biological organisms can continue to function as pointers to the Creator, even in a Darwinian cosmos. This article explores and extends these recent arguments. I analyze four different strategies for arguing that the wisdom of the Creator is apparent in biological organisms. The basic underlying assumption is that the products of some larger whole can reflect the rationality and designedness of that whole.