Ozone layer called the ozone-oxygen cycle. Chemically, this can be described as: About 90 percent of the ozone in the atmosphere is contained in the stratosphere. Ozone concentrations are greatest between about , where they range from about 2 to 8 parts per million. If all of the ozone were compressed to the pressure of the air at sea level, it would be only thick. Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation coming from the sun. Extremely short or vacuum UV (10–100
Layer Jump Recording Layer Jump Recording Layer Jump Recording (LJR) is a writing method used for DVD-R DL (Dual Layer). It permits recording the disc per increments called session (see Optical disc authoring), a.k.a. multi-session. It also permits a faster closing of the disc by saving extraneous padding when the amount of recorded data does not fill-up the disc. It overcomes these limitations of Sequential Recording (SR), the writing method usually applied to write-once optical media. The layer jump is a switch (jump) between the layer closer to the laser head (referred as L0) to the farther layer (referred as L1), or vice