Atmosphere nitrogen content

Another point that one has to observe from analysis of Figure 10, is that despite the different precursor atmospheres, and consequently different N precursor partial pressures in the deposition, there is a coincidence of the deposition rate behavior upon nitrogen content (for mixtures other than C2H-N2). This points to a strong dependence of growth kinetics with nitrogen content. 

Other studies showed the same trends discussed earlier. Films obtained by RF-PECVD, deposited at about the same conditions in other precursor atmospheres [79], showed the same behavior, with the Id/Iq and wq following about the same dependence on nitrogen content as the one shown in Figure 23. 

On the other hand, films deposited by RFPECVD in CH2-N2 atmospheres showed a different behavior [54]. In this study, in addition to the reported enhanced maximum nitrogen incorporation of 22 at.% (see Section 2.3.1), an almost constant behavior of the Raman parameters was observed for nitrogen content up... 

FIG. 29. C and N sp- fractions as functions of the nitrogen content in films deposited by magnetically enhanced RFPECVD in CH4-He-N2 atmospheres. (Reproduced from [14].)... 

In addition, excessive use of fuels with a high sulfur and nitrogen content causes sulfuric and nitric acids in the atmosphere from sulfur dioxide and nitrogen... 

Acid rain. Lakes in some areas of the world are now registering very low pH s because of excess acidity in rain. This was first noticed in Scandinavia and is now prevalent in eastern Canada and the northeastern U.S. Normal rainfall is 5.6 (because of CO2 in the air forming H2CO3). However, excessive use of fossil fuels (especially coal) with high sulfur and nitrogen content cause sulfuric and nitric acids in the atmosphere from the sulfur dioxide and nitrogen oxide products of combustion. Some rain in the Adirondack Mountains of upper New York State has been measured with a pH of 3.0. This problem is not specific to the chemical industry but should be of concern to all of us. 

In spite of the variability of the sum calculated from the nitrogen content and hygroscopicity the effect of the nitrogen content on the hygroscopicity can be expressed by a straight line. In Fig. 109 (after de Pauw) straight-lines corresponding with different relative moistness of atmosphere (f/F) are shown. 

The high-boiling distillates, such as the atmospheric and vacuum gas oils, are not usually produced as a refinery product but merely serve as feedstocks to other processes for conversion to lower-boiling materials. For example, gas oils can be desulfurized to remove more than 80% of the sulfur originally in the gas oil with some conversion of the gas oil to lower-boiling materials (Table 6-11). The treated gas oil (which has a reduced carbon residue as well as lower sulfur and nitrogen contents relative to the untreated material) can then be converted to lower-boiling products in, say, a catalytic cracker where an improved catalyst life and volumetric yield may be noted. 

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