time signal emission
121microscope — /muy kreuh skohp /, n. 1. an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye. 2. (cap.) Astron. the… …
122Dark matter — Not to be confused with antimatter, dark energy, dark fluid or dark flow. For other uses, see Dark Matter (disambiguation) …
123Electromagnetic compatibility — (EMC) is the branch of electrical sciences which studies the unintentional generation, propagation and reception of electromagnetic energy with reference to the unwanted effects (Electromagnetic Interference, or EMI) that such energy may induce.… …
124Photomultiplier — tubes (photomultipliers or PMTs for short), members of the class of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near infrared ranges of the electromagnetic spectrum.… …
125Dipole antenna — A schematic of a half wave dipole antenna connected to an unbalanced coaxial cable. Better practice is to connect the balanced dipole to the unbalanced line with a balun. A dipole antenna is a radio antenna that can be made of a simple wire, with …
126Hydrogen line — For hydrogen lines in general, see Hydrogen spectral series. The hydrogen line, 21 centimeter line or HI line refers to the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. This… …
127School bus — This article is about vehicles specifically designed and manufactured for carrying students to and from school. For information about school transportation in general, see student transport. School Bus Front 3/4 view of a typical North American… …
128Plug-in hybrid — The Chevrolet Volt is the first mass production plug in hybrid available in the United States. A plug in hybrid electric vehicle (PHEV), plug in hybrid vehicle (PHV), or plug in hybrid is a hybrid vehicle which utilizes rechargeable batteries, or …
