[化] 电子能谱; 电子能谱学; 专家系统

[医] 低于模糊意识(低于下意识)

[ noun ]
a radioactive transuranic element produced by bombarding plutonium with neutrons
<noun.substance>

Es \Es\ n.
the chemical symbol for {einsteinium}, a transuranic element
with atomic number 99. The atomic weight of the longest-lived
isotope, with a half-life of 276 days, is 254. The first
isotope discovered, having atomic weight 253 and a half-life
of 20 days, was recognized in 1952 in the debris from a
hydrogen bomb test. As much as 3 micrograms of einsteinium
were produced by a complex process involving long irradiation
of plutonium isotopes in nuclear reactors. Its chemical
properties are those of a trivalent actinide element. --HCP61

Syn: einsteinium, atomic number 99.
[WordNet 1.5 +PJC]