Period 6 element devices though concerns about the element's toxicity have led to mercury thermometers and sphygmomanometers being largely phased out in clinical environments in favor of alcohol-filled, galinstan-filled, digital, or thermistor-based instruments. It remains in use in scientific research applications and in amalgam material for dental restoration. It is used in lighting: electricity passed through mercury vapor in a phosphor tube produces short-wave ultraviolet light which then causes the phosphor to fluoresce, making visible light. Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray other metal resembles tin but discolors when exposed to air. The
SN 2002cx suggesting that SN 2002cx is similar to SN 1991T which also lacked such lines. This spectrum for SN 2002cx has a low expansion velocity measuring only ~6400 km s. This marked one way in which it was different from SN 1997br, as SN 1997br's expansion velocity was ~10,400 km s at the same point relative to its own B-band maximum. At the time of measurement SN 2002cx's expansion velocity was the lowest measured for an early time type Ia, Another spectrum taken on 2002 May 20, 1 day before B-band maximum light, showed little evolution from the one taken on