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Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number; [5] siderophiles shown in yellow Graphs of abundance against atomic number can reveal patterns relating abundance to stellar nucleosynthesis and geochemistry.
For example, 1 μs −1 would mean 10 6 disintegrations per second: (10 −6 s) −1 = 10 6 s −1, [4] whereas 1 μBq would mean 1 disintegration per 1 million seconds. Other names considered were hertz (Hz), a special name already in use for the reciprocal second (for periodic events of any kind), and fourier (Fr; after Joseph Fourier ). [ 4 ]
There are three known stable isotopes of oxygen (8 O): 16 O, 17 O, and 18 O. Radioactive isotopes ranging from 11 O to 28 O have also been characterized, all short-lived. The longest-lived radioisotope is 15
The first nanotube ropes (20 mm long) whose tensile strength was published (in 2000) had a strength of 3.6 GPa, still well below their theoretical limit. [41] The density is different depending on the manufacturing method, and the lowest value is 0.037 or 0.55 (solid). [37]
Less often, it is stated as percentage of all fission products, so that the percentages sum to 100%. Ternary fission , about 0.2–0.4% of fissions, also produces a third light nucleus such as helium-4 (90%) or tritium (7%).
Its neutron absorption cross section for thermal neutrons is high at 15200 barns, about 38% of 149 Sm's absorption cross section, or about 20 times that of 235 U. Since the ratios between the production and absorption rates of 151 Sm and 149 Sm are almost equal, the two isotopes should reach similar equilibrium concentrations.
Naturally occurring lithium (3 Li) is composed of two stable isotopes, lithium-6 (6 Li) and lithium-7 (7 Li), with the latter being far more abundant on Earth. Both of the natural isotopes have an unexpectedly low nuclear binding energy per nucleon (5 332.3312(3) keV for 6 Li and 5 606.4401(6) keV for 7 Li) when compared with the adjacent lighter and heavier elements, helium (7 073.9156(4) keV ...
6.37 ⋅ 10 7 at 273.15 K; 5.71 ⋅ 10 7 at 300K; 4.15 ⋅ 10 7 at 400K. [41] International Annealed Copper Standard (IACS) pure =1.7×10 −8 Ω•m =58.82×10 6 Ω −1 •m −1. For main article, see: Copper in heat exchangers. The TPRC recommended values are for well annealed 99.999% pure copper with residual electrical resistivity of ρ 0 ...