infrared heating element
41Vacuum tube — This article is about the electronic device. For experiments in an evacuated pipe, see free fall. For the transport system, see pneumatic tube. Modern vacuum tubes, mostly miniature style In electronics, a vacuum tube, electron tube (in North… …
42chemistry — /kem euh stree/, n., pl. chemistries. 1. the science that deals with the composition and properties of substances and various elementary forms of matter. Cf. element (def. 2). 2. chemical properties, reactions, phenomena, etc.: the chemistry of… …
43moon — mooner, n. moonless, adj. /moohn/, n. 1. the earth s natural satellite, orbiting the earth at a mean distance of 238,857 miles (384,393 km) and having a diameter of 2160 miles (3476 km). 2. this body during a particular lunar month, or during a… …
44Moon — /moohn/, n. Sun Myung /sun myung/, born 1920, Korean religious leader: founder of the Unification Church. * * * Sole natural satellite of Earth, which it orbits from west to east at a mean distance of about 238,900 mi (384,400 km). It is less… …
45spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… …
46Crystal oscillator — A miniature 4 MHz quartz crystal enclosed in a hermetically sealed HC 49/US package, used as the resonator in a crystal oscillator. A crystal oscillator is an electronic oscillator circuit that uses the mechanical resonance of a vibrating crystal …
47electricity — /i lek tris i tee, ee lek /, n. 1. See electric charge. 2. See electric current. 3. the science dealing with electric charges and currents. 4. a state or feeling of excitement, anticipation, tension, etc. [1640 50; ELECTRIC + ITY] * * *… …
48global warming — an increase in the earth s average atmospheric temperature that causes corresponding changes in climate and that may result from the greenhouse effect. [1975 80] * * * Potential increase in global average surface temperatures resulting from… …
49Microwave — This article is about the electromagnetic wave. For the cooking appliance, see Microwave oven. For other uses, see Microwaves (disambiguation). A microwave telecommunications tower on Wrights Hill in Wellington, New Zealand Microwaves, a subset… …
50luminescence — luminescent, adj. /looh meuh nes euhns/, n. 1. the emission of light not caused by incandescence and occurring at a temperature below that of incandescent bodies. 2. the light produced by such an emission. [1885 90; < L lumin (see LUMEN) +… …
