Analysis of cement pastes for triethanolamine

This report describes our efforts to analyze cement pastes for triethanolamine. This analysis can be efficiently accomplished after short hydration times ($\text{ca.}$ 3 min.) by gas chromatography or infrared spectroscopy. Only trace amounts of the amine are detected, however, after 24 hours of hydration. The infrared spectrum of the material extracted after 24 hours of hydration is different from that of the amine, suggesting that triethanolamine - cement reactions occur during hydration.     

An optimized π/2 distributed feedback laser

The effects of a periodicity interruption (phase slip) in distributed feedback lasers are investigated with attention given to the practical aspects of today's semiconductor lasers in the 1.5 μm region. We find that effects on gain threshold and mode discrimination should be large and favorable if the size and placement of a phase slip are correct.