Fast transport path

Long term protection by LiA102 is probably much better than suggested by the current density around -1000 mV, due to the further blocking of the fast transport paths as has been shown before for other alloys with a very much lower A1 content. 

Surface diffusion can also provide a fast transport path, and can thus also give rise to rapid growth along the surface. Although this situation is quite different from that of gas transport which was just described, the resultant morphologies can often be indistinguishable. Particularly striking examples of such phenomena are found for silicate formation reactions as illustrated in Fig. 8-12. 

It must have a porous nanostructure that allows a fast transport of protons (generated from water oxidation) to the underlying proton-conductive membrane, avoid surface recombination between protons and electrons (which should have different paths of transport), and have an optimal interface with the membrane. 

Tlie aim of this chapter is to provide an overview of materials where fast transport of alkali metal cations and protons is observed. A general discussion of factors affecting conductivity and techniques used to study ion migration paths is followed by a review of the large number of cation conductors. Materials with large alkali ions (Na-Cs) are often isostructural and therefore examined as a group. Tire lithium conductors with unique crystal structure types and proton conductors with unique conduction mechanisms are also discussed. 

Bueno, P.R. and E.R. Leite, Nanostructured Li ion insertion electrodes. 1. Discussion on fast transport and short path for ion diffusion. Journal of Physical Chemistry B, 2003. 107 pp. 8868-8877... 

Fig. 14 Grain boundary precipitate growth showing solute transport path during precipitate growth according to the collector-plate mechanism. Solute B is transported to the a-a grain boundary and then along the boundary to form the P precipitate. Diffusion-controlled precipitate growth results in solute depletion from the a phase along the homophase boundary due to fast boundary transport [44].

Fano interference, 32, 38 Fast electron distribution, 134 Fast electron generation, 123 Fast electron transport, 125 Fast electrons, 176 Fast-ignition, 124 Femtosecond supercontinuum, 94 Feynman s path integral, 73 Feynman s propagator, 76 Field parameter, 172 Filamentation, 82, 84, 112 Floquet ladder, 11 Fluorescence, 85, 125 FROG, 66 FROG-CRAB, 66... 

In the presence of the spacer (Fig. 17.35a), an initially high photocurrent value ( 6 mA/cm2) is achieved, but, due to the larger spacing between the two electrodes, the diffusion of the electron mediator is not fast enough to supply new reduced mediator to the Ti02/dye interface from which, under irradiation, is constantly depleted. Thus, a steady photocurrent value, significantly lower than the initial spike, is attained after a few seconds. In Fig. 17.35b, the reduced diffusional path for the electron mediator allows for a more effective mass transport that accounts for the generation of a stable photocurrent without the observation of photoanodic relaxation processes. 

Proton conducting copolymers of vinylphosphonic acid and 4-vinylimidazole have been reported recently by Bozkurt et al. [7]. Since the imidazole ring can act as a proton hopping site in the polymer matrix [8-10], these copolymers had ionic conductivity of about 10 S cm at 60°C without solvent or salt. To realize fast proton transport in copolymer systems, it is essential to design an ion conductive paths that uses the IL domain. 

Due to the limited response time of suitable sensors fast sorption or gas transport processes on a time scale below a second are hard to monitor. To significantly improve the resolution in time an interferometric pressure sensor can be applied. The central part of the interferometric pressure sensor presented is a Michelson-interferometer this set-up is sensitive to changes in gas pressure as the index of refraction, and thus the optical path length for a laser beam within the interferometer, is a function of the gas density. 

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