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13-letter words containing o, c, u, r

  • electron tube — (electronics)   (Or tube, vacuum tube, UK: valve, electron valve, thermionic valve, firebottle, glassfet) An electronic component consisting of a space exhausted of gas to such an extent that electrons may move about freely, and two or more electrodes with external connections. Nearly all tubes are of the thermionic type where one electrode, called the cathode, is heated, and electrons are emitted from its surface with a small energy (typically a Volt or less). A second electrode, called the anode (plate) will attract the electrons when it is positive with respect to the cathode, allowing current in one direction but not the other. In types which are used for amplification of signals, additional electrodes, called grids, beam-forming electrodes, focussing electrodes and so on according to their purpose, are introduced between cathode and plate and modify the flow of electrons by electrostatic attraction or (usually) repulsion. A voltage change on a grid can control a substantially greater change in that between cathode and anode. Unlike semiconductors, except perhaps for FETs, the movement of electrons is simply a function of electrostatic field within the active region of the tube, and as a consequence of the very low mass of the electron, the currents can be changed quickly. Moreover, there is no limit to the current density in the space, and the electrodes which do dissapate power are usually metal and can be cooled with forced air, water, or other refrigerants. Today these features cause tubes to be the active device of choice when the signals to be amplified are a power levels of more than about 500 watts. The first electronic digital computers used hundreds of vacuum tubes as their active components which, given the reliability of these devices, meant the computers needed frequent repairs to keep them operating. The chief causes of unreliability are the heater used to heat the cathode and the connector into which the tube was plugged. Vacuum tube manufacturers in the US are nearly a thing of the past, with the exception of the special purpose types used in broadcast and image sensing and displays. Eimac, GE, RCA, and the like would probably refer to specific types such as "Beam Power Tetrode" and the like, and rarely use the generic terms. The cathode ray tube is a special purpose type based on these principles which is used for the visual display in television and computers. X-ray tubes are diodes (two element tubes) used at high voltage; a tungsten anode emits the energetic photons when the energetic electrons hit it. Magnetrons use magnetic fields to constrain the electrons; they provide very simple, high power, ultra-high frequency signals for radar, microwave ovens, and the like. Klystrons amplify signals at high power and microwave frequencies.
  • electrophorus — A device for repeatedly generating static electricity by induction.
  • encourageable — Able to be encouraged; suggestible.
  • encouragement — The action of giving someone support, confidence, or hope.
  • encouragingly — In an encouraging manner.
  • encrustations — Plural form of encrustation.
  • enculturation — The gradual acquisition of the characteristics and norms of a culture or group by a person, another culture, etc.
  • equimolecular — (chemistry) Containing the same number of molecules (of two or more compounds).
  • estrous cycle — the regular female reproductive cycle of most placental mammals that is under hormonal control and includes a period of heat, followed by ovulation and complex changes of the uterine lining
  • eta reduction — eta conversion
  • ethnocultural — Relating to or denoting a particular ethnic group.
  • eurocommunism — the policies, doctrines, and practices of Communist Parties in Western Europe in the 1970s and 1980s, esp those rejecting democratic centralism and favouring nonalignment with the Soviet Union and China
  • excursionists — Plural form of excursionist.
  • faculty board — the governing body of a faculty
  • false colours — a flag to which one is not entitled, flown esp in order to deceive
  • feature shock — (jargon)   (From Alvin Toffler's "Future Shock") A user's confusion when confronted with a package that has too many features and poor introductory material.
  • federal court — a court of a federal government, especially one established under the Constitution of the United States.
  • ferociousness — savagely fierce, as a wild beast, person, action, or aspect; violently cruel: a ferocious beating.
  • ferrochromium — a ferroalloy containing up to 70 percent chromium.
  • fibromuscular — (anatomy) Of or pertaining to both fibrous and muscular tissue.
  • fibrovascular — composed of fibrous and conductive tissue, as in the vascular systems of higher plants: a fibrovascular bundle.
  • flag of truce — a white flag displayed as an invitation to the enemy to confer, or carried as a sign of peaceful intention by one sent to deal with the enemy.
  • floor cushion — a cushion placed on the floor of a room for people to sit on
  • floor furnace — a small self-contained furnace placed just below the floor of the space to be heated.
  • floricultural — Of or pertaining to floriculture.
  • fluorescently — In a fluorescent manner; using fluorescence.
  • fluoroacetate — a toxic chemical compound, C2H2FNaO2, occurring naturally in certain plants, and commonly used as rat poison
  • fluorocarbons — Plural form of fluorocarbon.
  • fluorochromes — Plural form of fluorochrome.
  • fluorographic — of or pertaining to fluorography
  • fluoroplastic — any of the plastics, as Teflon, in which hydrogen atoms of the hydrocarbon chains are replaced by fluorine atoms.
  • fluoroscoping — Present participle of fluoroscope.
  • fluoroscopist — One who carries out fluoroscopy.
  • focal seizure — an epileptic manifestation arising from a localized anomaly in the brain, as a small tumor or scar, and usually involving a single motor or sensory mechanism but occasionally spreading to other areas and causing convulsions and loss of consciousness.
  • foldoc source — The source text of FOLDOC is a single plain text file. FOLDOC is also available on paper from your local printer but, at 700,000+ words, that would be about 2000 pages.
  • food security — an economic and social condition of ready access by all members of a household to nutritionally adequate and safe food: a household with high food security.
  • force majeure — an unexpected and disruptive event that may operate to excuse a party from a contract.
  • forced labour — labour done because of force; compulsory labour
  • forcing house — a place where growth or maturity (as of fruit, animals, etc) is artificially hastened
  • foreconscious — the preconscious.
  • fork luncheon — déjeuner à la fourchette.
  • form function — (jargon)   The shape of something designed. This term is currently (Feb 1998) in vogue among marketroids.
  • formicivorous — ant-eating.
  • formulaically — made according to a formula; composed of formulas: a formulaic plot.
  • formularistic — relating to formularization
  • fort huachuca — a military reservation and U.S. Army training center in SE Arizona, SE of Tucson.
  • fort mcmurray — a town in NE Alberta, in W Canada, on the Athabasca River.
  • fractiousness — refractory or unruly: a fractious animal that would not submit to the harness.
  • fractocumulus — low ragged slightly bulbous cloud, often appearing below nimbostratus clouds during rain
  • fractostratus — low ragged layered cloud often appearing below nimbostratus clouds during rain
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