| 释义 |
propellant, a. and n.|prəʊˈpɛlənt|
Also 7–9 -ent.
[ad. L. prōpellent-em, pr. pple. of prōpellĕre: see propel and -ent. The spelling with -ant, contrary to etymology but usual since the mid-19th c., is prob. due to the greater commonness of the suffix -ant.]
A. adj. Propelling, driving forward; spec. (of an explosive) Adapted for propelling a bullet, etc. from a fire-arm.
1644Bulwer Chiron. 43 The Hand propellent to the leftward. 1858Greener Gunnery 21 Gunpowder is an explosive propellant compound... The terms, explosive and propellant,..are not convertible; for a chemical mixture may possess the explosive power in a much higher degree than the propellant. 1919R. H. Goddard in Smithsonian Misc. Coll. LXXI. ii. 6 This enables high chamber pressures to be employed..and also permits most of the mass of the rocket to consist of propellant material. 1945Soap & Sanitary Chemicals Apr. 125/3 Methyl chloride is an excellent propellant gas for aerosols to be used against insects out of doors.
B. n.
a. Something that propels; a propelling agent; fig. an incentive, a stimulus; spec. an explosive for use in fire-arms.
1814Jebb in Knox & J.'s Corr. II. 189 Providence has placed me in a narrow sphere..without any of the propellents which variety affords. 1881Greener Gun 368 In all saloon rifles and pistols the propellant is fulminating powder contained in a small copper case. 1890Engineer 7 Feb. 117 Though not as a military propellant [guncotton] has been used with great success in sporting cartridges. 1917W. S. Churchill in M. Gilbert Winston S. Churchill (1977) IV. Compan. i. 125 What proportion of our total explosive or propellant output could be based upon 10 million gallons of whiskey? 1931L. H. Morrison Amer. Diesel Engines v. 129 The explosion of these lighter parts of the fuel provides the propellant whereby the remainder of the fuel is injected into the engine cylinder in a finely atomized condition. 1936W. S. Churchill in Second World War (1948) I. 538 By ammunition is meant projectiles (both bombs and shells) and cartridge-cases containing propellent. 1939W. Beveridge Blockade & Civilian Population 8 Fats, broadly speaking, are all directly convertible into munitions, because they can be used, and are very largely used, in making propellants. 1966McGraw-Hill Encycl. Sci. & Technol. V. 153/1 Besides black powder, which is mainly used in sporting rifles, the common gun propellants are either nitrocellulose or a mixture of nitrocellulose and nitroglycerine.
b. A substance that is used (alone, or reacting with another) as a source of the hot gases that provide the thrust in a rocket engine. Cf. fuel n. 3 c, oxidizer 1, monopropellant n. and a.
1919R. H. Goddard in Smithsonian Misc. Coll. LXXI. ii. 67 Let us assume, for case (a) (many small secondary rockets), as well as for case (b) (large secondary rockets), that the ratio of mass of metal to mass of propellant is the minimum reasonable amount that can be expected. 1948M. J. Zucrow Princ. Jet Propulsion & Gas Turbines xii. 467 The propellants employed in a rocket motor may be a solid, two liquids (fuel plus oxidizer), or materials containing an adequate supply of available oxygen in their chemical composition (mono-propellants). 1955Times 29 June 16/3 Some five years ago we faced a difficult decision as to the most suitable propellents for the type of rockets which we were developing. 1957Space-flight I. 51/1 A propellant can be either fuel or oxidizer. 1967New Scientist 21 Sept. 594/2 Project officials ordered a series of critical tests to determine just how much propellant would be available for use after the main retrorocket had been fired. 1974Sci. Amer. Aug. 7/1 (Advt.), Launch weight of the spacecraft was only 1,108 pounds, including 66 pounds of propellant and 122 pounds of science instruments.
c. The compressed fluid in an aerosol container or the like that causes its contents to be ejected.
1945Soap & Sanitary Chemicals Apr. 127/1 Nitrous oxide also has a pressure too high for it to be practical as a propellant. 1957H. R. Shepherd in E. Sagarin Cosmetics Sci. & Technol. xxxvi. 804 While some aerosol cosmetics are made with a single propellent, it is customary to use a mixture or a solution of propellents. 1966McGraw-Hill Encycl. Sci. & Technol. V. 279/1 In the small first-aid water fire extinguisher, a propellant must be provided. Usually this is carbon dioxide. 1973Daily Tel. 21 Aug. 15/7 The propellent in the anti-perspirant caused freezing in the lung tissues resulting in loss of oxygen and death. Ibid. 15/8 A variety of compressed or liquified bases are used in aerosols and technically known as propellents. Most are halogenated hydrocarbons, which are also refrigerants, and sniffing of such propellents is a recognised form of drug abuse in Britain and the United States. 1978N.Y. Times 30 Mar. 62/3 The nitrous-oxide cartridges are made for use as the propellant in restaurant-sized equipment for whipping cream and non-dairy toppings. |