NRF meaning in Academic & Science ?

Nuclear resonance fluorescence (NRF) is a nuclear process in which a nucleus absorbs and emits high-energy photons called gamma rays. NRF interactions typically take place above 1 MeV, and most NRF experiments target heavy nuclei such as uranium and thorium

This process is used for scanning cargo for contraband. Its far more effective than just using x-rays because x-rays can only see the shape of the item in question. With nuclear resonance fluorescence its possible to see what the molecular structure is and thus, distinguish between salt and cocaine without even opening the container. (from National Geographic Magazine, February 2018, article: They Are Watching Us, by Robert Draper)