Nitrogen signal

This resembles the trends observed for amines and nitro groups. STO-3G charges [43] show that the nitrogen signal [157] is farther downfield as electronic charge increases at this atom. 

N chemical shifts react very sensitively to the configuration in these compounds in the analogous N-hexyl derivative the nitrogen signal at d — 64 was assigned to the c/.v-compound and that at <5 = 74 to the trans-isomer475. 

Spectra. All EPR measurements were made with a Varian 100 kc. modulation spectrometer. Spin concentrations were estimated by comparison with solid diphenylpicrylhvcurazyl. Numbers of radicals were assumed to be proportional to signal height times width squared. Temperature dependence plots were obtained by controlling the temperature of the resonance cavity with cooled or heated nitrogen. Signal intensities of the temperature plot were estimated by comparing with the intensity of the sample at 25°C. 

Figure 26.3 continued (c) FA of the nitrogen signal left, the pure component spectra right, the concentrations profile the sputtering time per cycle was 30 s. 

An estimate of the silane coverage could be made on the basis of the glass substrate signal attenuation and the carbon or nitrogen signal. This method of... 

In the 15N NMR spectrum of the systems (29 X = O or S) the chemical shifts of the nitrogens at position 1 correspond reasonably well with the nitrogen signals in benzo[c]-l,2,5-oxadiazole ( —35.6 ppm) and benzo[c]-l,2,5-thiadiazole (49.1 ppm). The nitrogens at position 3 appear to be deshielded by the effect of nitrogen at position 4. In the thiadiazine rings the pyridine-like nitrogens at... 

As determined by XPS analysis, the surface composition and O/C and N/C elemental ratios for 5 W and 15 W PEO-like and Ag/PEO-like films, following incubation in the protein solutions are illustrated in Table 1 for a power of 5 W. The data (Table 1) demonstrate that the PEO-like coatings are effective at reducing and/or preventing protein adsorption. The PEO-like films completely prevented the adsorption of albumin, as XPS did not detect a nitrogen signal. Moreover, the O/C ratio of the film is maintained after albumin exposure. 

One additional consideration for making a final choice which has not yet been discussed is that of endpoint detection during etch back and etch selectivity. In the case of TiN a good etch selectivity of CVD-W over TiN (say 15 1) is obtained with commonly used gases. As well, TiN provides an easily detectable nitrogen signal for optical endpoint detection. 

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