Wave splitting

OS 92] [R 32] [P 72] For radial movement from a center position, wave splitting was found [68]. Two new reaction zones were formed from a part of the circular reaction zone (Figure 4.100). 

Figure 4.100 Wave splitting of the reaction zone (white circle) in an electric field. Top view of the monitored area (3x3 cm). Numbers show the time intervals after the electric field was switched on ( = 4.06 V cm" ) [68. ...

The electrochemistry of dioxoosmium(VI) complexes has also been extensively studied. The tra 5-dioxoosmium(VI) complexes of polypyridyl and macrocyclic tertiary amine ligands display very similar proton-coupled electron transfer couples. In aqueous solutions at pH < 5-7 the cyclic voltammograms of n-a i-[0s (0)2(bpy)2] show a remarkable reversible three-electron couple and a one-electron Os coimle. In the Pourbaix diagram two break points are observed in the pH dependence of the Os couple, which correspond to the pAa values of Os —OH2 and Os —(OHXOH2) (Figure 10). The redox reactions are shown in Equations (41)-(43). At pH >8 the 3e Os wave splits into a pH-independent le Os wave and a 2e/2H" Os wave (Equations (44) and (45)). 

In many cases the potential application of single-walled carbon nanotubes is associated with solubility of this nanomaterial in different solvents. Unfortunately, nanotubes are poorly soluble in the most of organic solvents and are insoluble in water, and this fact especially hinders biological using SWNT. Weak solubility of SWNT is a result of substantial van der Waals attractions between nanotubes aggregated in bundles. To solve nanotubes in water without any covalent functionalization, a surfactant would be added into aqueous solution, and then this mixture is suspended by sonication. It is supposed that the sound wave splits bundles in aqueous solution. A surfactant in suspension adsorbed onto the nanotube surfaces precludes aggregation of nanotubes in bundles. 

All of these considerations cast doubt on the use of A i/2 (AGc) for measuring the electronic communication between redox sites and the ability of the molecule to function as a wire. Regardless of its true nature, the wave splitting resembles some kind of polarization effect. It does not correspond to a transfer process, and has no counterpart in the usual behavior of a macroscopic wire. 

As stated above, electrochemical wave splitting in itself cannot be actually considered as a manifestation of wire-like properties. However, some spectacular or intriguing examples deserve to be quoted. 

Finally, complexes with (acac)Ru(III)(acac-) end groups and diethynylan-thracene, diethynylthiophene, or triethynyl spacers, described by Hoshino et al. [19], exhibit wave splittings for the Ru(rV/III) couple (but not for Ru(III/II)). Interestingly, the diethynylanthracene spacer proved particularly efficient (cf. Section 1.5.1, under (bpy)2Ru(pp-) for its role in mixed-valence compounds). 

Meltzer A. and Christensen N. (2001) Nanga Parbat crustal anisotrophy implication for interpretation of crustal velocity structure and shear-wave splitting. Geophys. Res. Lett. 28(10), 2129 -2132. 

In some ways the Superior Province appears different from other Archaean cratons worldwide. For example, it exhibits thicker than average crust and long uninterrupted geological belts, not commonly seen on other cratons. The Superior Province is also unusual in the sense that it exhibits very large shear-wave splitting values in the heart of the craton and very little in the surrounding Proterozoic Trans-Hudson shear zone. It is more normal for the surrounding mobile... 

Clitheroe, G. vander Hilst, R. D. 1998. Complex anisotropy in the Australian lithosphere from shear-wave splitting in broad-band SKS-records. 

Fouch, M. j., Fischer, K. M., Parmentier, E. M., Wysession, M. E. Clarke, T. J. 2000. Shear wave splitting, continental keels and patterns of mantle flow. Journal of Geophysical Research, 105, 6255-6276. 

Kay, I., Sol, S., Kendall, J.-M. 5 others 19996 Shear wave splitting observations in the Archean craton of Western Superior. Geophysical Research Letters, 26, 2669-2672. 

Savage, M. 1999. Seismic anisotropy and mantle deformation What have we learned from shear wave splitting Reviews of Geophysics, 37, 65-106. 

Silver, P. G. Savage, M. K. 1994. The interpretation of shear wave splitting parameters in the presence of two anisotropic layers. Geophysical Jourrml International, 199, 949-963. 

Barruol, G. Kern, H. 1996. Seismic anisotropy and shear-wave splitting in lower crust and upper-mantle rocks from the Ivrea Zone-experimental and calculated data. Physics of the Earth and Planetary Interiors, 95, 175-194. 

Fouch et al. (1999) compared model simulations of asthenospheric flow and seismic observations, and found that a significant proportion of the shear-wave splitting can be explained by the deflection of asthenospheric flow around a cratonic root. In our study we are interested in the extra complication of anisotropy in flowing mantle plume material that hes beneath and around continental keels. 

Upper-mantle anisotropy and shear-wave splitting... 

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