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McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A technique used in atomic physics to study the structure and dynamics of atomic ions of any element in any state of ionization. For this purpose, a beam of fast ions is sent through a very thin foil. The ion-foil interaction shakes up the electronic shells of the projectile and, after leaving the foil, the ions shed surplus energy by emitting photons, and sometimes electrons. The energies and intensities of these particles yield spectral information on the projectile.
Industry:Science
A technique used in telecommunications transmission systems whereby the instantaneous frequency of a carrier signal is determined by the characteristics of an information signal, the so-called modulating signal. Frequency modulation (FM) is a form of angle modulation. For systems in which the modulating signal is digital in nature, the term frequency-shift keying (FSK) is usually employed.
Industry:Science
A technique used in telecommunications transmission systems whereby the phase of a periodic carrier signal is changed in accordance with the characteristics of an information signal, called the modulating signal. Phase modulation (PM) is a form of angle modulation. For systems in which the modulating signal is digital, the term “phase-shift keying” (PSK) is usually employed.
Industry:Science
A technique, also called liquid extraction, for separating the components of a liquid solution. This technique depends upon the selective dissolving of one or more constituents of the solution into a suitable immiscible liquid solvent. It is particularly useful industrially for separation of the constituents of a mixture according to chemical type, especially when methods that depend upon different physical properties, such as the separation by distillation of substances of different vapor pressures, either fail entirely or become too expensive.
Industry:Science
A technology that transports voice using data packets instead of circuit switching, which the traditional public switched telephone network (PSTN) uses. Voice over IP (VoIP), using packet technology, allows for more efficient transport of voice while providing the quality of service and reliability of PSTN.
Industry:Science
A technology that uses electrical wiring as a medium to transmit digital signals from one device that has been rendered capable of employing this technology to another. Power line communication (PLC) enables the communication of data as well as multimedia messages by superimposing digital signals over the standard 50- or 60-Hz alternating current (AC).
Low-speed power line communication has been used widely for some time in electrical utilities to provide voice communication, to control substations, and to protect high-voltage transmission lines. High-speed data transmission over power lines began in the late 1990s and was targeted to provide broadband Internet services and utility applications such as remote meter reading, as well as in home networking for data and multimedia communications. A short-range form of power line communication is also used for home automation and controls.
Industry:Science
A telescope adapted to the observation of the passage, or transit, of an astronomical object across the meridian of the observer. The astronomical transit instrument is the classic instrument of positional astronomy, which is the study of the positions and motions of astronomical objects. (The specific categories of astronomy concerned with these investigations are astrometry and celestial mechanics.) The chief variants of the classic design include the vertical circle, the horizontal transit circle, the broken or prism transit, the photographic zenith tube and, most commonly, the meridian or transit circle.
Industry:Science
A telescope or telescopes, their protective enclosures (if any), support and headquarters buildings, and the staff of astronomers, engineers, technicians, and other support personnel. The telescopes can be optical or infrared (reflecting or refracting) inside a corotating dome, or radio dishes without enclosures.
Industry:Science
A television broadcast, involving the transmission of the picture and sound portions of the program by separate transmitters at assigned carrier frequencies within the channel assigned to a television station. A telecast is intended for reception by the general public, just as is a radio broadcast. The picture may be either in black and white or in full color, using amplitude modulation, while the sound portion (in the United States) uses frequency modulation. The channels assigned for telecasts by the Federal Communications Commission, each 6 megahertz (MHz) wide, cover frequencies as follows: 54−72 MHz (channels 2 through 4), 76−88 MHz (channels 5 and 6), 174−216 MHz (channels 7 through 13), and 470−890 MHz (channels 14 through 83).
Industry:Science
A temperature-measuring device, originally an instrument that measures temperatures beyond the range of thermometers, but now in addition a device that measures thermal radiation in any temperature range. This article discusses radiation pyrometers. For other temperature-measuring devices
Industry:Science
