Long period pseudo

Figure 8.46. Construction of observable distances (dal, Lf) in a paracrystal from its fundamental distances, L (not observable pseudo long-periods), and dcl (observable crystallite thicknesses). Advancing to the bottom the relations to the observable thicknesses of amorphous layers, dm, and the long periods, L , are sketched...

Figure 3.41. The oI40-AuCu(II) structure. This superstructure contains 10, slightly distorted, tP4-AuCu( I) pseudo-cells. The long-period ordering corresponds to a periodic shift of the structure (every five cells along the orthorhombic Yaxis) by />. (at I c) in the % c plane. The anti-phase domain contains 5 AuCu(I) pseudo-cells.

The formation in solution of nickel complexes with TV-substituted ethylenediamines has been studied over a long period by many authors.707 Solutions of nickel(II) complexes with TV-substituted diamines often exhibit equilibria between pseudotetrahedral and pseudo-octahedral species. These equilibria are displaced towards the pseudotetrahedral species when the temperature increases. Complexes Ni(TV,TV-Et2en)2X2691 with poorly coordinating anions are thermochromic. This behaviour has been investigated by means of calorimetric and NMR studies.708,709... 

These y(r) curves were analyzed using a pseudo-two-phase structure model, which has a broad distribution of long period and lamellar thickness and a diffuse phase boundary at the interface of the crystal and the amorphous regions as shown by Figure 11.4. 

The structural parameters, that is, the average thickness of the crystalline phase , the thickness of the amorphous phase <4>, and the long period L (= <4> -I- ), were obtained from y(r) based on the pseudo two-phase structure model in which the electron density changes smoothly from pc to pa as shown by Figure 18.5a. 

In Zurich, IS cases of pseudo-lupus eiythema-todes syndrome were observed in patients treated for long periods with Venocuran . It was subsequently found that among pseudo-LE cases in Germany there were many patients who had been taking a similar product (Venopytonum). Both products contain, alongside the natural extracts, a quantity of phenopyrazone (1,2-diphenyl-3,5-pyrazolidine-dione) which may well have been responsible for this complication. The trade name Venopytonum is, however, also in use for other products in the series to which phenopyrazone has not been added (14). 

Figure 19 Schematic effect of the STAR operator on 2JCH and 3,/CH couplings. The vicinal component of magnetization in the long-range response that is two-bond coupled to a protonated carbon experiences modulation, which serves as a pseudo-evolution for this coupling. In contrast, the vicinal component of magnetization in the long-range response that is three-bond coupled to a protonated carbon does not exhibit a F, skew. Homonuclear modulation during the evolution period f, is still present, as the full experiment is not a constant-time experiment.

In all four cases, tlie initial reaction rates at the start of illumination in the continuous-feed photoreactor were higher than the pseudo-steady-state reaction rates the reaction rates declined over time until pseudo-steady-state operation was achieved. Tliis apparent deactivation phenomenon, often observed with aromatic contaminants, is discussed in Sec. III.E. In a transient reaction system, the time required to reach pseudo-steady-state operation also appears to increase in the same order as the reaction rates. For example, for the continuous photocatalytic oxidation of aromatic contaminants at 50 mg/m in a powder-layer photoreactor, the time required for pseudo-steady-state operation to be achieved was reported to be approximately 90 min for benzene, 120 min for toluene, and as long as 6 hr for wz-xylene [50,51]. Under such conditions, the difference in reaction rates between the aromatic contaminants is magnified by the fact that the more reactive aromatics retain their higher transient reaction rates for longer periods (Fig. 7). 

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