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Exciplex-based fluorescence was employed for the remote, nonintrusive, instantaneous and point measurements of fuel droplet temperature. A hydrocarbon droplet doped with naphthalene and TMPD was allowed to evaporate in a heated gaseous mixture of oxygen, nitrogen, carbon dioxide and water. The fluorescence emission spectra from a droplet subjected to nitrogen laser excitation were measured with an optical multichannel analyzer. Photographic observation showed that a droplet fluoresced with a green color at room temperature. As the temperature was raised, fluorescence became purple. The ratio of fluorescence emission intensities at two different wavelengths was an appropriate criterion for in situ determination of droplet temperature. Oxygen in the ambient gas was found to be a major quencher for the fluorescence. Droplet velocity relative to the ambient gas did not have an appreciable influence on the fluorescence emission spectra.

Tuning to a frequency in conventional radio has changed conceptually to tuning to a network or program type in the radio data system (RDS), where fast, error-free switching to the best alternate frequency (AF) should be done as transparently as possible. The exact bit reception rate with relation to multipath interference becomes more important than the conventional S/N or RF sensitivity for the subcarrier filter and demodulator, where the dynamic behavior of multipaths must be considered. In addition to bit error correction, data error correction must be made by comparison with recursively transmitted data. Quick switching to the best or a good enough AF is done by collecting precise data during good reception and storing it ready for use in a data processor in addition to the conventional DTS processor.