Pseudo-layering

Synthesis of copper and zinc complexes of 5,7-dimethyl-l,2,4-triazolo [l,5-a]pyrimidine has been reported [93AX(C)1902 94AX(C)510], Reaction of copper(II) thiocyanate with 5,7-dimethyl-l,2,4-triazolo[l,5-a]-pyrimidine (l) gave three different complexes two isomers of [Cu(NCS)2L2]2 and Cu(NCS)2L2 H20 (84IC2803). The mononuclear complexes, bis(thiocyanato-N)bis(6-methyl-l,2,4-triazolo[l,5-a]pyrimidine-jV-3)copper(II) and the polynuclear pseudo-layered complexes, bis(thio-cyanato-A0bis(5-methyl-l,2,4-triazolo[l,5-a]pyrimidine-A -3)copper(II) were prepared (89POL2313). 

If we use the X sites to join the different slices, we obtain a three-dimensional structure of formula MX3 which is realized in ResB and CuMgAl2. An improper or pseudo-layer structure can be derived from this arrangement by weakening this latter bond as occurs in the PuBra-type family (Figure 2). In this way the coordination number has been reduced to 8, but the layer character is accidental or incomplete and based on the weakness or absence of the M—X bonds between the puckered MX3 layers. Other closely related structures are those of the ZrSea and TaSea type. 

Kolev, T., B.B. Koleva, T. Spassov, E. Chemeva, M. SpiteUer, W.S. Sheldrick, and H. Mayer-Figge. 2008. Synthesis, spectroscopic, thermal and structural elucidation of 5-amino-2-methoxypyridine ester amide of squaric acid ethyl ester A new material with an infinite pseudo-layered stracture and manifested NLO application. J. Mol. Struct. 875 372-381. 

The structural relationships in Bi203 are more complex. At room temperature the stable fonn is monoclinic o -Bi203 which has a polymeric layer structure featuring distorted, 5-coordinate Bi in pseudo-octahedral iBiOs units. Above 717°C this transforms to the cubic -form which has a defect fluorite structure (Cap2, p. 118) with randomly distributed oxygen vacancies, i.e. [Bi203D]. The )3-form and several oxygen-rich forms (in which some of the vacant sites are filled... 

Fig. 16.13b (Se-Fax 180 pm, Se-Feq 167 pm, with axial and equatorial angles subtended at Se of 169.3° and 96.9°, respectively).However, these pseudo-tbp molecules are arranged in layers by weaker intermolecular interactions to neighbouring molecules so as to form an overall distorted octahedral environment with two further Se F at 266 pm (Fig. 16.13b) somewhat reminiscent of the structure found earlier for Tep4 (see Fig. 16.13c and below).

In certain concentrated acidic solutions, e.g. H2SO4, nickel, whilst not truly passive, may exhibit pseudo-passivity owing to crystallisation of a layer of nickel salt (in cone. H2SO4 probably /3-NiS04-6H20) on the surface". ... 

The mechanism of sealing has been shown to involve an initial dissolution and reprecipitation of hydrated aluminium oxide on the pore walls, pseudo-boehmite gel formation within the pores, and conversion of this to crystalline boehmite at the film surface. The presence of an intermediate layer close to the film surface, in which the identity of the original pores has been lost, has also been recognised . 

Pseudo-Code Implementation The Back-propagation algorithm outlined above may be implemented by following seven steps, to be applied for each pattern p . Assume we have a neural net with L layers (/ 1,2,...,L). Let h represent the output of the neuron in the / layer hf is therefore equal to the input, <7 . The weight of the connection between li- and h[ will be labeled by Wij. 

The novel element in these models is the introduction of a third phase in the Hashin-Rosen model, which lies between the two main phases (inclusions and matrix) and contributes to the progressive unfolding of the properties of the inclusions to those of the matrix, without discontinuities. Then, these models incoporate all transition properties of a thin boundary-layer of the matrix near the inclusions. Thus, this pseudo-phase characterizes the effectiveness of the bonding between phases and defines a adhesion factor of the composite. 

In order to alleviate this singular and unrealistic situation, a series of models was presented in this study, in which a third pseudo-phase was considered as developed along a thin boundary layer between phases, during the polymerization of the matrix, whose properties depend on the individual properties of the phases and the quality of adhesion between them. 

The electrical double layer has been studied at the interface of acidified (pH = 3) KCIO4 and K2SO4 solutions in contact with an Sn solid drop electrode with an additionally remelted surface (SnDER).616 The E, is independent of ctl as well as of the electrolyte. Weak specific adsorption of CIO4 at SnDER is probable around <7 = 0. This view is supported by the high value of/pz for SnDER/H20 + KCIO4 (fpz = 1 -27). A value of fpz = 0.99 for SnDER/H20 + K2S04 indicates that the surface of SnDER is geometrically smooth and free from components of pseudo-capacitance.616... 

Layered dichalcogenides, such as sulfides or selenides of Ti, Mo, W, Zr, Ta, Nb, V, and Cr, are able to dissolve certain alkali metal ions and in some cases posttransition (pseudo-alkali) metal ions (Cu, Ag ), via a mechanism in which the guest is inserted between the dichalcogenide layers. Lithium ion intercalation into TiS2, which among layered dichalcogenides has been one of the most prominent cathode... 

As expected, the estimated values were found to be closer to the correct ones compared with the estimated values when the water-oil ratios are only matched. In the 2nd run, the horizontal permeabilities of layers 5 to 10 (6 zones) were estimated using the value of 200 md as initial guess. It was found necessary to use the pseudo-inverse option in this case to ensure convergence of the computations. The initial and converged profiles generated by the model are compared to the observed data in Figures 18.25a and 18.25b. 

Subsequently, Mitchell s group in Vancouver, by means of a tensor-LEED study17 of the Cu (110)-(2 x 3)N surface structure, supported a reconstruction model in which the topmost layer is described as a pseudo-(100)-c(2 x 2)N overlayer with metal corrugation of about 0.52 A in the reconstructed layer. Each nitrogen adatom is almost coplanar with the local plane formed by the four neighbouring copper atoms. Of the four N atoms present in the unit mesh, three are also bonded to Cu atoms in the layer below and therefore are five coordinate. 

Of crucial significance in deciding between various models have been estimates of the number of copper atoms required to transform the surface into a (2 x 3)N phase. This was the approach adopted by Takehiro et al 2 in their study of NO dissociation at Cu(110). They concluded that by determining the stoichiometry of the (2 x 3)N phase that there is good evidence for a pseudo-(100) model, where a Cu(ll0) row penetrates into the surface layer per three [ll0]Cu surface rows. It is the formation of the five-coordinated N atoms that drives the reconstruction. The authors are of the view that their observations are inconsistent with the added-row model. The structure of the (2 x 3)N phase produced by implantation of nitrogen atoms appears to be identical with that formed by the dissociative chemisorption of nitric oxide. 

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