Step edge Subject

These data illustrate that using lE-AFM in this way it is possible to elucidate the different dissolution mechanisms of the calcite surface subject to various acid challenges. In particular, proton-assisted dissolution from the surface is initially observed to occur via the formation of tiny pits with mono and dual unit cell layer depths, as well as by the removal of material from step edges. Increasing the acid challenge ultimately results in the formation of micron-sized shallow etch pits. 

Where the shield faces join (i.e. top to side, side to front, etc. ), provisions had to be made for shielding and differential thermal expansion. Stepped joints were used at the edges of the shields to prevent any direct radiation paths. The gas seal between shield faces is formed by long rubber strips clamped over the junction to each of the shields. Deterioration of these gas seals has been a problem. However, the flexibility required rules out all materials except rubber which has a limited life when subjected to radiation, high temperatures, and the reactor atmosphere. 

Shark s Teeth. A striation (q.v.) of dagger-like step fractures from the scored edge to the compression edge (the region in which the brittle material is subject to compressive stress). 

When growth stops there naturally must be edges, corners, steps, and kinks formed on the particle surface as shown in Fig. 3. Metal atoms that find themselves in such positions are much more chemically reactive, due to their accessibility and their coordinative unsaturation. These sites are believed to be very important in some catalytic processes. Likewise many catalysis experts believe that only certain geometrical arrangements of metal atoms are capable of carrying out a specific chemical (catalytic) transformation of an adsorbed molecule (the so-called ensemble effect). We will deal with these subjects in more detail later. 

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