Identifiable fluorescent markers were developed as tracers to tail suspects using phenanthrene, anthracene, fluoranthene, pyrene, perylene, and coronene in vaseline. Vaseline was used as a carrier of the marker. Of the six compounds in the vaseline, perylene and fluoranthene were readily observed under ultraviolet (UV) light at a wavelength of 365 nm. All six compounds were identified selectively and sensitively without interference of vaseline using a high performance liquid chromatograph (HPLC) with a fluorescence detector. The detection limit was much less than 1 ng, corresponding to that of the observation behavior under UV light. The results showed that each component with vaseline was more effective than the individual component for the delay in degradation. The case examples of the fluorescent markers are shown.

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‘‘Vacuum fired’’ (1050 °C) type 304 stainless steel (SS304) surfaces were investigated with scanning electron microscopy and Auger electron spectroscopy. The grain boundaries of the surface were vague and shallow, which occurred due to elemental diffusion at high temperature in vacuum. The newly formed oxide layer of the vacuum fired surface was much thinner, and could be said to be finer in microstructure than the native layer of an ‘‘as-received’’ surface. A vacuum fired (1050 °C) SS304 chamber was evacuated by a sputter ion pump whose vessel was pretreated by vacuum firing (1050 °C). An extremely high vacuum of 1.5×10−9 Pa (N2 equivalent pressure) was indicated by an extractor ionization gauge after a mild bake (170 °C) following an air exposure. The outgassing rate of the chamber wall at the elapsed time of one day after a mild bake (170 °C) was roughly estimated as low as 2×10−11 Pa ℓ/s cm−2 (N2 equivalent value) by an orifice method. Vacuum firing has the effects of degassing the gas molecules soluted in the interior of stainless steel wall, and of forming a new, thin, and fine (in microstructure) oxide layer on the surface.

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