Search results
Results from the WOW.Com Content Network
Isotope analysis is the identification of isotopic signature, ... Problems such as the mixing and re-using of metals from different sources, limited reliable data and ...
The COLEX plants in Oak Ridge had a very rough start in 1955 with major problems in this entirely new, complicated, and potentially hazardous technology. [2] Stockpiles of lithium-6 and lithium-7 from that period have been available until recently to meet the relatively small domestic and world demand [ 3 ]
Other isotopes including 2 H, 3 H, 3 He, 6 Li, 7 Li, and 7 Be are much rarer; the estimated abundance of primordial lithium is 10 −10 relative to hydrogen. [7] The calculated abundance and ratio of 1 H and 4 He is in agreement with data from observations of young stars.
An isotopic signature (also isotopic fingerprint) is a ratio of non-radiogenic 'stable isotopes', stable radiogenic isotopes, or unstable radioactive isotopes of particular elements in an investigated material. The ratios of isotopes in a sample material are measured by isotope-ratio mass spectrometry against an isotopic reference material.
Carbon-14 is a radioactive isotope of carbon, with a half-life of 5,730 years [30] [31] (which is very short compared with the above isotopes), and decays into nitrogen. [32] In other radiometric dating methods, the heavy parent isotopes were produced by nucleosynthesis in supernovas, meaning that any parent isotope with a short half-life ...
Technetium-99m (99m Tc) is a metastable nuclear isomer of technetium-99 (itself an isotope of technetium), symbolized as 99m Tc, that is used in tens of millions of medical diagnostic procedures annually, making it the most commonly used medical radioisotope in the world.
Isotope dilution analysis is a method of determining the quantity of chemical substances. In its most simple conception, the method of isotope dilution comprises the addition of known amounts of isotopically enriched substance to the analyzed sample.
Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?