neutron radiation barrier
11aerospace industry — Introduction assemblage of manufacturing concerns that deal with vehicular flight within and beyond the Earth s atmosphere. (The term aerospace is derived from the words aeronautics and spaceflight.) The aerospace industry is engaged in the …
12radioactivity — /ray dee oh ak tiv i tee/, n. Physics, Chem. the phenomenon, exhibited by and being a property of certain elements, of spontaneously emitting radiation resulting from changes in the nuclei of atoms of the element. Also called activity. [1895… …
13Nuclear fusion — Nuclear physics Radioactive decay Nuclear fission Nuclear fusion Classical dec …
14Nobel Prizes — ▪ 2009 Introduction Prize for Peace The 2008 Nobel Prize for Peace was awarded to Martti Ahtisaari, former president (1994–2000) of Finland, for his work over more than 30 years in settling international disputes, many involving ethnic,… …
15Mathematics and Physical Sciences — ▪ 2003 Introduction Mathematics Mathematics in 2002 was marked by two discoveries in number theory. The first may have practical implications; the second satisfied a 150 year old curiosity. Computer scientist Manindra Agrawal of the… …
16nuclear fission — fission (def. 2). [1885 90] * * * Division of a heavy atomic nucleus into two fragments of roughly equal mass, accompanied by the release of a large amount of energy, the binding energy of the subatomic particles. The energy released in the… …
17nuclear reactor — Physics. reactor (def. 4). Also called nuclear pile. [1940 45] * * * Device that can initiate and control a self sustaining series of nuclear fission reactions. Neutrons released in one fission reaction may strike other heavy nuclei, causing them …
18Manhattan Project — This article is about the atomic bomb project. For other uses, see Manhattan Project (disambiguation). Manhattan District The Manhattan Project created the first nuclear bombs. The Trinity test …
19Atom — The atom is the smallest unit of an element that retains the chemical properties of that element. An atom has an electron cloud consisting of negatively charged electrons surrounding a dense nucleus. The nucleus contains positively charged… …
20nuclear fusion — fusion (def. 4). [1895 1900] * * * Process by which nuclear reactions between light elements form heavier ones, releasing huge amounts of energy. In 1939 Hans Bethe suggested that the energy output of the sun and other stars is a result of fusion …
