Alpha decay helium produced on Earth is the result of the alpha decay of underground deposits of minerals containing uranium or thorium. The helium is brought to the surface as a by-product of natural gas production. Alpha particles were first described in the investigations of radioactivity by Ernest Rutherford in 1899, and by 1907 they were identified as He ions. By 1928, George Gamow had solved the theory of alpha decay via tunneling. The alpha particle is trapped in a potential well by the nucleus. Classically, it is forbidden to escape, but according to the (then) newly discovered principles of quantum mechanics,
Nitrogen-15 nuclear magnetic resonance spectroscopy content of nitrogen atoms (tetrazoles, triazines and their annelated analogs) . Insensitive nuclei enhanced by polarization transfer (INEPT) is a signal resolution enhancement method. Because N has a gyromagnetic ratio that is small in magnitude, the resolution is quite poor. A common pulse sequence which dramatically improves the resolution for N is INEPT. The INEPT is an elegant solution in most cases because it increases the Boltzmann polarization and lowers T values (thus scans are shorter). Additionally, INEPT can accommodate negative gyromagnetic ratios, whereas the common nuclear Overhauser effect (NOE) cannot. Nitrogen-15 nuclear magnetic resonance spectroscopy Nitrogen-15 nuclear magnetic resonance