Cryogenics necessary to use a silicon diode for accuracy. Cryogenics In physics, cryogenics is the production and behaviour of materials at very low temperatures. A person who studies elements that have been subjected to extremely cold temperatures is called a "cryogenicist". It is not well-defined at what point on the temperature scale refrigeration ends and cryogenics begins, but scientists assume a gas to be cryogenic if it can be liquefied at or below . The U.S. National Institute of Standards and Technology has chosen to consider the field of cryogenics as that involving temperatures below . This is a logical dividing
Ship prefix Ship prefix A ship prefix is a combination of letters, usually abbreviations, used in front of the name of a civilian or naval ship. Prefixes for civilian vessels may either identify the type of propulsion, such as "PS" for paddle steamer, or purpose, such as "RV" for research vessel. Civilian prefixes are often used inconsistently, and frequently not at all. Sometimes a slash is used to separate the letters, as in "M/S". Naval prefixes came into use as abbreviations for longer titles, such as "His/Her Majesty's Ship" in the British Royal Navy, abbreviated "H.M.S." and then "HMS". Earlier uses often