Q layers

In the present terminology, a three-way data array is defined by n rows, p columns and q layers, with indices i,j and k, respectively. 

The (q,b,b,q)-layers are not favoured as fivefold bulk terminations by the dynamical LEED simulations, neither in i-AlPdMn [33] nor in i-AlCuFe [18], likely because the top q-planes in the terminations are less rich in A1 atoms than the corresponding top b-planes in the (b,q,(a)q,b)-layers. Dynamical LEED confirms the (b,q,(a)q,b)-layers as terminations on which the top surface plane is an Al-plane (93% A1 by... 

We have here reviewed our work on the surfaces of icosahedral quasicrystals since 1997. We have discovered a confirmation that the maximum dense fivefold (q,b,b,q)-layers are the fivefold bulk terminations in the model This... 

A significant example has been given by Gordon, Kapadia, and Malakis (1976). These authors considered hexagonal lattices made of Q successive layers (see Fig. 3.12). The layer of rank C contains 6 (2Q - 1) sites and, consequently, the total number N of lattice sites with Q layers is given by... 

Other stacking of T and Q layers may be considered, where the atoms of a layer touch only two atoms of the layer below. They give rise to pure sequences of type b, v or d. Examples are [Pa] (protactinium), Zn [Ba02] and [71812]. For a Q stacking of this sort an example is Si°[Th]Q. In Fig. 3 are represented the more common pure stacking sequences with their corresponding symbols. 

These sulfides consist of two types of alternating, mutually non-commensurate layers. One type (Q layers) has pseudotetragonal symmetry and belongs to the PbS or SnS archetype. The other type (H) are octahedral or trigonal prismatic layers. 

Figure 18. The crystal structure of cannizzarite, Pb4 i S.f27 (Matzat, 1979). In order of decreasing size the circles indicate S, Pb, (Pb,Bi) and Bi filled and open circles indicate atoms at two discrete levels along the 4 A axis, 2 A apart. Double-octahedral H layers are Intercalated by double Q layers.

Weibullite alternation of two-planes-thick Q layers and double-octahedral H layers, respectively 5 1/2 Q subcells and 3 1/2 H subcells broad interlayer match 6Q / 3 1/2 H composition/structure non-consen/ative boundaries are composed of trigonal prisms represent glide planes in the layer pile. 

Pb4ln3BiyS.,g alternation of four-planes-thick Q layers and single-octahedral H layers, respectively 4Q and 3H subcells broad interlayer match 3Q/2H. The composition- and structure non-conservative boundaries are based on a combination of Vertical and horizontal trigonal prisms, respectively MeSg g 3 MeSg, and represent out-of-phase boundaries. 

Junoite alternation of two-planes thick Q layers and single H layers, the layer fragments are respectively 3Q and 2 1/2 H subcells broad interlayer match is 3 1/2 Q / 2H subcell (out-of-phase) shear planes are almost perpendicular to layers, they display doubling of... 

Ariga, K., Hill, J.P., Ji, Q. Layer-by-layer assembly as a versatile bottom-up nanofabrication technique for exploratory research and realistic application. Phys. Chem. Chem. Phys. 9, 2319-2340 (2007). doi 10.1039/b700410a... 

The cathodic protection on damaged galvanized items depends on (a) the coating thickness, the width of the bared area or scratch, and (c) the local climate. Allowance must be made for any extra loss of zinc due to cathodic protection effects or due to exposure of more zinc surfaces to the environment. It also has been shown that coatings of Al/Zn alloys alone offer no or only poor cathodic protection. More or less the same applies to duplex systems, where the paint coat covers the zinc (-q) layer, thus preventing or retarding the liberation of the necessary ions. 

Table 72. Separation and detection of the colchicum alkaloids on silica gel Q layers [178]... 

Schaefer s method was improved, taking into consideration the dissolution of the q-layer into the molten solder until the copper concentration in the solder reaches the saturation limit, as well as the additional growth due to the reprecipitation of Cu as Tj after the Cu reaches it saturation limit (Ref 7). In consideration of Cu dissolution into the molten solder to reach the Cu solubility limit, they assumed that Cu dissolution into the molten solder is entirely from the dissolved q IMC. They also assumed that during cooling from the reflow temperature, Cu becomes incrementally supersaturated. The excess Cu atoms in the solder react with readily available Sn to form ri in the bulk solder, or migrate to the interface and precipitate on the interfacial rj layer. The portion that precipitated at the interface is calculated based on the growth controlled by diffusion, and the diffusion coefficient of Cu in liquid Sn was used (Ref 56). 

Dense layer with planar interface. The morphology of the q-layer varies gradually from a cellular film with a rugged interface to a dense film with a scalloped interface as the Pb content, temperature, and reaction time increased. The 8-phase is always dense and nearly planar. 

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