| 释义 |
▪ I. rem, a.
Slang abbrev. of remanded ppl. a.
1887[see bust n.3 d].
▪ II. rem, n.1|rɛm|
Pl. rem, rems.
[f. initial letters of roentgen equivalent man.]
Orig., a quantity of ionizing radiation having the same effect on human tissue as one roentgen of X-rays. The dosage in rems is now calculated by multiplying the dosage in rads by the relative biological effectiveness. Cf. rep7.
1947Nucleonics Oct. 38/2 The rep and rem units were introduced by Dr. H. M. Parker. Ibid. 39/2 Roentgen-equivalent-man (or mammal), rem... One rem is the estimated amount of energy absorbed in tissue which is biologically equivalent in man to 1 r of gamma- or X-rays. By definition: 1 rem = 83/RBE erg/gm tissue. 1957Encycl. Brit. XVI. 591/1 The biological effects of radiation are not solely dependent on the amount of energy released; it is also a question of how highly localized the energy is. Such considerations have led to another unit, the rem, supposed to be that dose of radiation which has the same biological effect as 1 rad of X-radiation. 1958W. D. Claus Radiation Biol. & Med. xviii. 431 The dose in rem is obtained by multiplying the physical dose in rads by the RBE appropriate to the situation. 1958Observer 5 Oct. 15/4 The most active watches..could deliver a dose of five rem (units of radioactive dose measurement) within five years. The International Commission on Radiological Protection has recommended that no one should receive an accumulated dose of more than five rem by the age of 30. 1975Nature 27 Mar. 278/2 Fifteen rem is equivalent to 1·5 rad of alpha radiation (since alpha radiation is considered 10 times as carcinogenic as gamma radiation). 1976Sci. Amer. Nov. 31/2 If the fresh fission products from one megaton of fission were spread uniformly over a perfectly flat area of 1,000 square miles, the gamma-ray dose rate one meter above the ground would be about 250 rems per hour after 10 hours.
▪ III. rem
obs. f. raven n.1, ream n.1, n.2, realm. |