“second”的概念、定义、翻译、参考文献-科学参考

　

单词	second
释义	second Physics 1. Symbol s. The SI unit of time equal to the duration of 9 192 631 770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium–133 atom. 2. Symbol ″. A unit of angle equal to 1/3600 of a degree or 1/60 of a minute. Astronomy The fundamental unit of time in the SI system. It is defined as the duration of 9 192 631 770 cycles of the radiation from the transition between two hyperfine levels in the ground state of caesium-133. This definition is designed to produce 86 400 s in the mean solar day. See also Leap Second. Chemical Engineering 1. (Symbol s) A base SI unit of time equal to 1/60th of a minute and 1/3600th of an hour. Since May 2019, it is defined by taking the fixed numerical value of the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom as 9 192 631 770 cycles of radiation. 2. (Symbol ″) An angle equal to 1/60^th of a minute or 1/3600^th of a degree. Biology Symbol s. The SI unit of time equal to the duration of 9 192 631 770 periods of the radiation corresponding to the transition between two hyperfine levels of the ground state of the caesium–133 atom.
随便看	necrology necrosis nectar Nectarian Nectarian system needle ice needle problem needs Ne'eman, Yuval Nefertiti (14th century bc) negation negation as failure negative negative acknowledgment negative bias negative binomial distribution negative booster negative charge negative correlation negative direction negative equity negative exponential distribution negative eyepiece negative feedback negative freedom

　

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