Oxygen intensity

Our calculations disprove this point of view. The fact is that at high temperatures oxygen intensively consumes energy for dissociation without... 

The electrons that are provided by photosystem I are finally used to reduce CO2 to carbohydrates, while in photosystem II, water is oxidized to oxygen. Intense research over many decades has partially revealed the extremely complicated mechanism of natural photosynthesis. It follows that it is obviously rather difficult to imitate this in an artificial photosynthesis that is intended to convert and store solar energy in simple but energy-rich chemicals. Different approaches have been developed to solve this problem (i). It has been suggested to facilitate artificial photosynthesis by the assistance of redoxactive metal complexes in homogeneous systems. Generally, photoredox reactions of metal... 

The positions of the vague maxima were not reproducible. In our opinion this type of behaviour is due to small amounts of Si and/or B subsurface impurities, which were not detectable in our AES analysis. Small amounts of these elements are known to form stable oxides at the surface (15-19). Type I and type II, however, were fully reproducible. Type I (fig.3d) is a Pt-like behaviour comparable to those of pure Pt (fig.3a) and the Pt-rich alloy (fig.3b). Type II (fig.3e), which shows a maximum for the oxygen intensity likewise at 800 K, is a Rh-like behaviour (compare fig.3c). The maximum relative intensity is lower than that observed for pure Rh. The figures also show that for the Rh-rich alloy the dashed line is much lower relative to the solid line than for pure Rh. This might indicate that the surface oxygen is more easily removed by the residual gas on the alloy than on the pure Rh. It was shown earlier that on a Pt-Rh alloy surface oxygen preferentially occupies the Rh sites leaving the Pt sites initially free (10). If many free Pt sites are present at the surface... 

Figure 4.2. Stern Volmer plot of quenching of oxygen intensity and lifetime of tryptophan in solution. Source Lakowicz. J. R. and Weber. G. 1973. Biochemistiy, 12, 4161 4170. Authorization of reprint accorded by the American Chemical Society.

Fig. 19. Rate versus extent of polymerization of HDDA, recorded at various light intensities. Initiator 0.25wt.-% DMPA. Continuous curves sample compartment flushed with nitrogen containing <2 ppm of oxygen. Dashed curves with 58 ppm of oxygen. Intensities are in mW cm". (From Ref. with permission)...

Ruiz S, Papy E, Da Silva D, Nataf P, Massias L, Wolff M, Bouadma L. Potential voriconazole and caspofungin sequestration during extracorporeal membrane oxygenation. Intensive Care Med 2009 35 183. ... 

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