Preferential growth

Figure 15. Schematic of preferential growth of octapods along eight (111) directions from a cube.

Figure 13. Preferential growth of pore on 35 C from (100) n-Si with back illumination. After Ronnebeck et.

It is not easy to provide an explanation of the origin of these unusual forms simply based on preferential growth at the tip of a prismatic crystal. Various models have been proposed, for example ... 

Japanese twins of quartz have attracted interest since ancient times because they exhibit a remarkably platy V-shape, in contrast to the hexagonal prismatic morphology of coexisting single crystals. Since they grow on substrate, the V-shape was assumed to represent the upper half of an X-shape [12], which implies that the Japanese twins are penetration twins. The platy form of Japanese twins has been explained as being due to preferential growth at a re-entrant corner formed by two individuals. If the platy form is indeed simply due to the re-entrant corner effect, we should expect a variation of forms, from V-shape to fan-shape, as the effect proceeds, as shown in Fig. 10.9. If, however, it represents the upper half of an X-shape, Japanese twins should be penetration twins, not contact twins. 

Van den Dries K and Vromans H. 2003. Experimental and modelistic approach to explain granulate inhomogeneity through preferential growth. Eur. J. Pharm. Sci. 20 409-417. 

Surface reconstruction observation has also revealed that the surface structure is different in GaN epilayers on GaAs and 3C-SiC substrates, i.e. the former show 2x2 and c(2x2) structures, and the latter show 4x1 and lxl structures. It has been clarified that 2x2 and c(2x2) structures on GaAs substrates are due to the adsorption of As on the surface [58], Besides this modification of reconstruction structure, As ambient pressure during the growth has been shown to have several surfactant effects, such as the stabilisation of the flat surface and preferential growth of the cubic phase [28,59-61], Attempts to improve the quality of cubic GaN epilayers by these As surfactant effects have been reported [60,61],... 

Analysis of the Z8 peptide engineered virus demonstrated preferential growth of ZnS particles oriented in the [001] direction perpendicular to the viral surface. Alternatively, the shorter A7 peptide sequence resulted in high density layers of ZnS (8-16 quantum dots per 10 nm of virus) particles due to... 

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