Chemical vapor depositionChemical vapor deposition (CVD) is a vacuum deposition method used to produce high-quality, and high-performance, solid materials. The process is often used in the semiconductor industry to produce thin films. In typical CVD, the wafer (substrate) is exposed to one or more volatile precursors, which react and/or decompose on the substrate surface to produce the desired deposit. Frequently, volatile by-products are also produced, which are removed by gas flow through the reaction chamber.
Amplitude modulationAmplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the amplitude (signal strength) of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its phase, as in phase modulation.
AM broadcastingAM broadcasting is radio broadcasting using amplitude modulation (AM) transmissions. It was the first method developed for making audio radio transmissions, and is still used worldwide, primarily for medium wave (also known as "AM band") transmissions, but also on the longwave and shortwave radio bands. The earliest experimental AM transmissions began in the early 1900s. However, widespread AM broadcasting was not established until the 1920s, following the development of vacuum tube receivers and transmitters.
Documentary filmA documentary film or documentary is a non-fictional motion-picture intended to "document reality, primarily for the purposes of instruction, education or maintaining a historical record". Bill Nichols has characterized the documentary in terms of "a filmmaking practice, a cinematic tradition, and mode of audience reception [that remains] a practice without clear boundaries". Early documentary films, originally called "actuality films", lasted one minute or less.
Film genreA film genre is a stylistic or thematic category for motion pictures based on similarities either in the narrative elements, aesthetic approach, or the emotional response to the film. Drawing heavily from the theories of literary-genre criticism, film genres are usually delineated by "conventions, iconography, settings, narratives, characters and actors". One can also classify films by the tone, theme/topic, mood, format, target audience, or budget.
