Structural perpendicular media

Fortunately, other experimental parameters are sensitive to olefin triplet geometry and assist in the evaluation of the They include (1) the triplet lifetime, which (see Table 4) is long for nearly planar triplets (ms-p,s) and short for nearly perpendicular triplets (ns), (2) the magnitude of triplet-triplet excitation-transfer rate constants, e.g. which is large for planar and small for perpendicular triplets, (3) the shape of the triplet-triplet absorption spectrum and its dependence on structural or medium constraints to torsion about the olefinic double bond, (4) the fraction of quenching interactions which give 02( Ag), and (5) where applicable, the trans/cis decay ratio, 87(1 — 8 ), associated with the O2 quenching interaction. 

Both structures are maintained over thicknesses of up to several micrometers and confer a two-dimensional character to the medium. Charge transport is favored in the direction parallel to the film, that is, perpendicular to the molecular axis. 

The rate of the active transport of sodium ion across frog skin depends both on the electrochemical potential difference between the two sides of this complex membrane (or, more exactly, membrane system) and also on the affinity of the chemical reaction occurring in the membrane. This combination of material flux, a vector, and chemical flux (see Eq. 2.3.26), which is scalar in nature, is possible according to the Curie principle only when the medium in which the chemical reaction occurs is not homogeneous but anisotropic (i.e. has an oriented structure in the direction perpendicular to the surface of the membrane or, as is sometimes stated, has a vectorial character). 

Figure 4.34. Crystal structure of the neutral phase of TTF-CA. Crystallographic data from Le Cointe et al, 1995. (a) Projection of the ac-plane with the fe-direction pointing perpendicular to the plane. The molecular (101) plane, which contains the -direction, is indicated by a straight line, (b) Space-Ailing model of the CA (101) plane. C, O, S and Cl are represented by black, dark grey, medium grey and light grey balls, respectively. H atoms are omitted.

If definite stoichiometry is maintained in the exciplex formation, an isoemissive point similar to isosbestic point in absorption miy be observed. An interesting example of intra-molecular exciplex formation has been reported foi 9-methoxy-10-phenanthrenecarboxanil. The aniline group is not necessarily coplanar with the phenanthrene moiety but is oriented perpendicular to it. The u-elcctron located on its N-atom interacts with the excited -electron system and an intramolecular exciplex with T-bone type structure is formed in rigid glassy medium where rotation is restricted. Temperature dependence of fluorescence of this compound in methylcyclohexane-isopentane (3 1) solvent shows a definite isoemissive point (Figure 6.8). As the solvent melts and movement is restored to the molecule, structured fluorescence reappears. 

Assume that the fibers in a filter are cylindrical they are parallel to each other and are uniformly assembled. Consider cake filtration in which particles are collected with the deposited particles forming a layer of porous structure as shown in Fig. 7.13(a). Thus, to account for the total pressure drop, three basic flow modes are pertinent (1) flow is parallel to the axis of fibers (2) flow is perpendicular to the axis of the cylinder and (3) flow passes through a layer of a homogeneous porous medium. In the analysis of the first two modes given later, Happel s model [Happel, 1959] is used, while for the third mode, Ergun s approach [Ergun, 1952] is used. 

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