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An example is the Stone Wales defect in nanotubes, which consists of two adjacent 5-membered and two 7-membered atom rings. Schematic illustration of defects in a compound solid, using GaAs as an example. Amorphous solids may contain defects. These are naturally somewhat hard to define, but sometimes their nature can be quite easily understood.
The relationship is defined by a symmetry operation called a twin operation. [1] [2] The twin operation is not one of the normal symmetry operations of the untwinned crystal structure. For example, the twin operation may be reflection across a plane that is not a symmetry plane of the single crystal. [1] [2]
Grain boundaries are two-dimensional defects in the crystal structure, and tend to decrease the electrical and thermal conductivity of the material. Most grain boundaries are preferred sites for the onset of corrosion [1] and for the precipitation of new phases from the solid. They are also important to many of the mechanisms of creep. [2]
In macroeconomics, the twin deficits hypothesis or the twin deficits phenomenon, [1] is the observation that, theoretically, there is a strong causal link between a nation's government budget balance and its current account balance.
As the partial dislocations repel, stacking fault is created in between. By nature of stacking fault being a defect, it has higher energy than that of a perfect crystal, so acts to attract the partial dislocations together again. When this attractive force balance the repulsive force described above, the defects are in equilibrium state. [4]
Static Universe theory [14] Steady state theory, a model developed by Hermann Bondi, Thomas Gold, and Fred Hoyle whereby the expanding universe was in a steady state, and had no beginning. It was a competitor of the Big Bang model until evidence supporting the Big Bang and falsifying the steady state was found.
The Kirkendall effect is the motion of the interface between two metals that occurs due to the difference in diffusion rates of the metal atoms. The effect can be observed, for example, by placing insoluble markers at the interface between a pure metal and an alloy containing that metal, and heating to a temperature where atomic diffusion is reasonable for the given timescale; the boundary ...
The power of twin designs arises from the fact that twins may be either identical (monozygotic (MZ), i.e. developing from a single fertilized egg and therefore sharing all of their polymorphic alleles) or fraternal (dizygotic (DZ), i.e. developing from two fertilized eggs and therefore sharing on average 50% of their alleles, the same level of genetic similarity found in non-twin siblings).