| 释义 |
ˈover-ˈpressure
[over- 29 b, c.]
a. Excessive pressure; the act of pressing or fact of being pressed too hard (esp. with study or intellectual work); pressure (of a fluid) in excess of that which is normal or allowed for.
1644Vicars God in Mount 147 Being forced at last..by over-pressure of numbers. 1834H. Martineau Moral ii. 37 The over-pressure of the people upon its food. 1899Allbutt's Syst. Med. VII. 470 Overpressure in education has also been alleged as a factor. 1936B. Jones Elem. Pract. Aerodynamics xviii. 290 The pressure gages should be watched closely, especially before take-off. Overpressure indicates a stoppage in the line. 1941O. E. Patton Aircraft Instruments x. 153 The suction and overpressure tests are given to find out what will happen to the gauge if it is subjected to pressures below atmospheric or exceeding their normal range. 1962Trans. Faraday Soc. LVIII. 194 A quantitative hydrogenation of a solution of the polymer in benzene was attempted using..an over-pressure of hydrogen (ca. 700 mm). 1963Ann. Med. Internae Fenniae LII. 212 The idea of employment of over-pressure directed into the human organism may be questioned in principle. 1977Sci. Amer. Mar. 82/1 Just above the vocal folds are the two ‘false’ vocal folds, which are engaged when someone holds his breath with an over-pressure of air in the lungs.
attrib.1884Knight Dict. Mech. Suppl., Overpressure Valve, a valve which opens when a predetermined pressure in a boiler has been reached. A Safety Valve.
b. spec. The difference between the (highest) instantaneous pressure at a point subjected to a shock wave and the ambient atmospheric pressure.
1955Communications Pure & Appl. Maths. VIII. 340 We evaluated the D corresponding to the shock over⁓pressure of 5°. 1961Shell Aviation News No. 278. 9/2 It's quite conceivable that a ground overpressure of only 0·1 lb per square foot may be decidedly unacceptable to the farmer{ddd}and 0·04 lb per square foot to those who value peace and quiet. 1967Guardian 5 July 1/8 Overpressures will vary from 1 to 1·5 lb a sq. ft. which is less than the maximum Concord bang. 1975Sci. Amer. July 15/3 Overpressure is proportional to the energy released by a nuclear charge and is inversely proportional to the cube of the distance from the point of explosion. |