Scientific term for the low-temperature preservation of humans or animals, with the hope of future revival.
Cryonics is a field of research that freezes bodies in hopes of future medical technology.
冷凍保存 is general 'cryopreservation' or 'freezing storage', while 極低温科学 specifically refers to the field of cryonics with the goal of future revival.
Compound of 極低温 (extremely low temperature) + 科学 (science). A modern technical term.