smoke the ratio of indole (13.9 yug/cig.) to 1-methylindole (0.42 pg) is 100:3 and that of 3-methylindole (14.0 pg) to 1,3dimethylindole (0.28 pg) is 100:2. In the pyrolyzate, the ratios are 100:2.25 and 100:1.6. Despite the use of different analytical methods the indole value for the tryptophan pyrolysis (880 °C) is comparable to the 3% yield reported by Patterson et al. from the pyrolysis of tryptophan at 850 °C ( 14). This suggests that free and/or protein bound tryptophan in (14) J.
A single-channel x-ray spectrometer has been converted to a two-channel instrument. Two separate planes in a single lithium fluoride crystal are employed to reflect, simultaneously, two portions of the x-ray spectrum. The instrument has been used to measure trace quantities of lead in the form of particulate matter as an air pollutant. One crystal plane was used to reflect the lead Lα emission line while the second plane reflected background radiation near that line.
We are investigating by Raman microprobe measurements the superconducting and related phases in the LnBa2Cu3O7-x (for x=0 to 1) system where yttrium has been replaced by several of the lanthanide (Ln = Nd,Sm,Eu,Ho,Er) elements. The aim is to relate the observed optical spectra (Raman and fluorescence) to the compositional and structural properties of these solids as part of comprehensive materials characterization. The results are correlated with the methods of synthesis, the processing techniques of these materials, and their superconducting properties. Of relevance is the substitutional chemistry of these isostructural systems, the differences in the spectra, and their microanalytical usefulness for the detection of impurity phases, and the assessment of compositional homogeneity. The Raman spectra of most of these compounds are well understood from accounts in the literature.The materials examined here are mostly ceramic powders prepared by conventional solid state reaction techniques. The bulk samples are of nominally single-phase composition as determined by x-ray diffraction.
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