Faces, growing

FIGURE 14.11 a) Structure of a growing crystal face (i>) face growing on a lattice with a... 

Crystal habit (or morphology) is an important property for the industrial use of zeolites. Manipulating habit can be used to tailor the number of pores exposed to the surface of a crystal, as well as the length of pore channels. The shape of a crystal can vary because the different faces grow at different rates relative to one another. 

Fig. 7.163. The growth of a crystal, illustrating how a fast-growing face grows out of existence, while the slow-growing crystal faces remain.

Like the prince-bishop of Wurzburg, some early modern rulers expressed the hope that alchemy could fund various kinds of political projects. Without question, the territorial states of the empire faced growing costs in the sixteenth century. Many rulers simply needed an additional source of income to make up for budgetary shortfalls, and alchemy s promise of transmutation could easily seem to offer a solution. This financial crisis had deep roots since at least the fifteenth century, the princes, nobility, and clergy of the Holy Roman Empire had had difficulties generating enough revenue solely from their traditional sources of income in an... 

DiMasi—tall, soft-voiced, and bespectacled, with thinning gray hair—seems almost too passive to be the center of such controversy. Until he gets into the topic. Then his face grows stern, and hints of annoyance fleck his Boston accent. 

In Figure 6.18, the flat F faces, stepped S faces, and kinked K faces are shown for a cubic ciystal system. The rougher S and K faces grow very quickly and are rarely, if ever, observed. The ciystal habit is... 

Figure 11.25 Preferential growth on 111 faces results in spherical single crystal cuboctahedron growing into a cube bounded by 100 faces as the 111 faces grow out of existence.

In the case of an isotropic advancement rate of the step, a growth spiral with circular symmetry" is formed. Due to the character of its origin the spiral step can never disappear and the crystal face grows perpetually even at relatively lov supersaturations without the need of a two-dimensional nucleation. 

Figure 5.38 Morphological features of an Ag(lll) crystal face growing under ac modulated growth conditions in the system Ag(lll)/AgN03 (melt) at dc current density Me = niA cm, ac amplitude t ac = 150 mAcm 2 and T= 573 K [5.76], t/s = 0 (a) 600 (b) 1200 (c) 1800 (d). Front face areaA(in) = 1.57x10-4 cm2.

As already discussed above, the application of a cathodic overpotential step to a crystal face growing at steady state conditions leads to the formation of new growth pyramids at the emergence points of screw dislocations. The slope of these new pyramids is determined by the new final overpotential, rn, and is steeper than that of the pyramids growing at the initial overpotential, rji, before application of the potential step. If the new pyramids grow at rjf independently, i.e., without interaction or overlapping effects, they cover a part, Sex(0. of the crystal face surface given by [5.83]... 

Watanabe, T., Japanese Pharmaceutical Industry Faces Growing-and Shrinking—Pains, Business Japan 31 71-74,1986. 

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