PhotolithographyIn integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer, to protect selected areas of it during subsequent etching, deposition, or implantation operations. Typically, ultraviolet light is used to transfer a geometric design from an optical mask to a light-sensitive chemical (photoresist) coated on the substrate.
Median lethal doseIn toxicology, the median lethal dose, LD50 (abbreviation for "lethal dose, 50%"), LC50 (lethal concentration, 50%) or LCt50 is a toxic unit that measures the lethal dose of a toxin, radiation, or pathogens. The value of LD50 for a substance is the dose required to kill half the members of a tested population after a specified test duration. LD50 figures are frequently used as a general indicator of a substance's acute toxicity. A lower LD50 is indicative of increased toxicity. The test was created by J. W.
Violet (color)Violet is the color of light at the short wavelength end of the visible spectrum, between blue and invisible ultraviolet. It is one of the seven colors that Isaac Newton labeled when dividing the spectrum of visible light in 1672. Violet light has a wavelength between approximately 380 and 435 nanometers. The color's name is derived from the violet flower. In the RGB color model used in computer and television screens, violet is produced by mixing red and blue light, with more blue than red.
Lever arm shock absorberLever arm shock absorbers were the first form of hydraulic shock absorber or damper used for car suspension. They appeared in the 1930s and were most commonly used in the 1950s and 1960s, but were replaced by telescopic shock absorbers in the 1970s. One of the earliest patents for a hydraulic lever arm shock absorber was awarded in 1925 to Georges de Ram, who was already an established maker of friction disk shock absorbers. Hydraulic shock absorbers, invented by Ralph Peo in 1930, appeared as a development to replace the previous friction disks.
