Over-doped

Additive lamps Arc or microwave medium-pressure mercury vapor UV lamps that have small amounts of different metal halides added to the mercury in the lamp. The halides emit their characteristic wavelengths in addition to mercury additions (this term is preferred over doped lamps). 

Ranjit KT, Viswanathan B. Photocatalytic reduction of nitrite and nitrate ions over doped Ti02 catalyst. J Photochem Photobiol A Chem 1997 107 215-20. 

B. The Oxidation of Carbon Monoxide over Doped Nickel Oxide Catalysts.. 36... 

It was also found that isocyanate species adsorbed on Rh are significantly stabilized over the W -doped Rh/Ti02 catalyst and are present on the catalyst surface under all experimental conditions that lead toward formation of N2O in the gas phase. As a result, reduction of NO by CO over doped catalysts occurs at lower temperatures ( e50°C) compared to the undoped catalyst mainly due to expansion of the temperature window of N2O formation. 

Figure 9a Theoretical predictions of 7. Peaks 1, 2, 3 relate to the under-doped regime (compare with Figure 9b) while peak 4 relates to the over-doped regime (compare with Figure 9c). The broken lines are the expected effect of fluctuations not included in our model.

Figure 9c Experimental data from the Cambridge group (Cooper, Loram et al [29]) for YBCO(Ca 20%) for heat capacity in the over-doped regime...

Chester, A.W., Landis, P.S., and Scott, E.J.Y. (1978) Oxidize aromatics over doped cobalt. CHEMTECH, 366,... 

Capping layer over doped regions to prevent outdiffu-sion during thermal cycling... 

Lowering the reaction temperature also allows for greater control over doping levels in nanoparticles, as demonstrated for tin-doped InaGg. 

When the potential scan was extended to a more anodic region, an oxidation peak was observed at about 4.7V [17,18]. This is considered to be irreversible oxidation caused by over-doping. The diffusion of dopants in polyacetylene has been studied by some researchers, but the coefficient diffusion values show large discrepancies. Using the current pulse method and assuming one-dimensional linear diffusion. Will estimated the diffusion coefficient of BF4 anions in polyacetylene to be 6 x 10 cm s [19]. Takehara et al. estimated the diffusion coefficients of BF4, CIOJ, and PF ... 

Other features are consistent with non-phonon-mediated pairing in the hole-doped cuprates. The curve of vs. carrier concentration can be approximated by an inverted parabola with the maximum value of occurring at an optimal dopant concentration x (Uchida 1993). (Note that the terminology under-doped refers to values of x smaller than the optimally-doped value Xo, whereas over-doped refers values of x larger than Xo.) The isotope effect on Tc for optimally-doped material is essentially zero (i.e., Tc a with a wO M = ion mass) (Franck 1994). 

Although Y is one of the most often discussed reactive elements, its applicability to intermetaiiics is limited because of its low solubility. This tends to lead to the formation of Y-rich precipitates that can result in non-ideal behavior (e.g. Kuenzly and Douglass, 1974). Additions of Hf or Zr seem to be preferable. Adding too much RE can, however, be a problem when over-doping can lead to oxidation behavior worse than that of the undoped material (Doychak, 1994 Pint et al., 1996 Pint, 1998), e.g. when REs are added to improve mechanical properties. Addition of 0.2 at.% Hf to NiAl (Darolia and Walston, 1997) can result in initial improvements in oxidation behavior but could result in significant oxidation problems in long-term high-temperature oxidation because of internal oxidation of the Hf. 

Pahnqvist, A.E.C., Johansson, E.M., Jaras, S.G., and Muhammed, M. Total oxidation of methane over doped nanophase cerium oxides. Catal. Lett 1998, 56, 69-75. 

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