alkali feldspars containing diffusion domains with differing activation energy. Geochim. Cosmochim. Acta 55, 1435-1448. [Pg.604]

Diffusion domains determined by Ar released during step heating. [Pg.609]

spherical electrodes, these are more evident as the frequency decreases (i.e., longer potential pulses) and so the differences in the diffusion domains are more apparent. [Pg.515]

Farley, 2000 Reiners and Farley, 1999, 2001), but this relationship breaks down in samples subjected to intensive ductile or brittle deformation (e.g., Amaud and Eide, 2000 Kramar et al, 2001 Mulch et al, 2002). In general, it seems prudent to assume that a is related to the physical grain size when applying Equations (17) and (19) unless samples show textural evidence for the extensive development of subgrain boundaries that may act as fast diffusion pathways, or— in the case of K-feldspar— show direct evidence of the existence of multiple diffusion domains during incremental heating experiments. [Pg.1537]

Spin diffusion Domain sizing e.g. polymers, connectivity Caravatti et al. (1983), (1982)... [Pg.159]

All microparticles on the array surface will contribute to the observed current-voltage I-E response. To describe the random distribution, the following parameters are defined [35]. The microscopic coverage 0 refers to the fractional coverage of an individual diffusion domain (see next section) ... [Pg.193]

The Diffusion Domain Approach The so-called diffusion domain approach was first proposed by Amatore et al. [36], and has proved highly useful in several theoretically based reports on this subject to model the diffusion current at those randomly distributed spherical micro- (or nano-) particle arrays [35, 37-39]. [Pg.193]

The electrode surface can be understood as an ensemble of independent cylindrical diffusion domains of radius Tq with the respective solid microparticle at the center (Figures 6.13 and 6.14). [Pg.193]

These zones are approximated as being cylindrical, with the particle situated at the symmetry axis. If a random spatial distribution of microparticles is assumed, the respective diffusion domains (cylinders) are of different sizes, with a probability distribution function as follows [41] ... [Pg.193]

Figure 6.14 Coordinate system used to model the diffusion domain for a cylindrically approximated diffusion domain. The plane to be simulated is shaded [40]. |

Figure6.21 Simulated linearsweepvoltammograms for diffusion domains (see text). The system parameters are V = 0.1 Vs ... |

This is not dependent on the size of domains - that is, the size distribution of the diffusion domains. However, by assuming an electrochemically reversible stripping, Ep is given by (adapted from Refs [51, 52] to this simulation model) ... [Pg.206]

The scan rate dependence on peak potential makes it dear that, at high microscopic coverage, a near-linear dependence of p on ln(v) applies, with the slope approaching RT/2F. At low 6, however, a hemispherical diffusion becomes predominant. With higher scan rates, the diffusion layer will become thinner and the diffusion regime more planar. Adjacent diffusion domains will then overlap with each other. [Pg.207]

For particles whose diameter is larger than 10 xm, the diffusion domain is the diffraction one. This phenomenon is characterised by UV-visible spectra with absorbance values slightly dependent on wavelength (diffraction and Mie/diffraction domain), which are almost independent from the wavelength. The ratio between absorbance values at 200 and 800 nm is about 2. [Pg.151]

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