A computer operating system (the basic software running on a computer, underneath things like word processors and spreadsheets). Unix is designed to be used by many people at the same time (it is multi-user) and has TCP/IP built-in. It is the most common operating system for servers on the Internet. Apple computers' Macintosh operating system, as of version 10, is based on Unix.
The portion of the UV spectrum covering the wavelength range between 320nm and 400nm. This spectral region is used for many medical, UV curing and photolithographic applications. The earth’s atmosphere (at sea level) absorbs all wavelengths shorter than UVA. Prolonged exposure to UVA radiation will cause sunburn.
UVB is the portion of the UV spectrum that covers the wavelength range between 280nm and 320nm. UVB radiation is typically used in UV curing and photolithographic applications as well as in certain medical applications. Exposure to UVB radiation (from lamps or electric arcs) can cause severe sunburn and cause eye damage.
UVC is the portion of the UV spectrum that extends from 190nm to 280nm. UVC is usually employed in water treatment and sterilization applications. UVC is also used in UV curing and photolithography in microelectronics applications. Exposure to UVC radiation (from lamps, arcs, or lasers) can cause severe biological damage.