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Effective Neutron Multiplication Factor
In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nuclear reaction may be the fission of heavy isotopes (e.g., uranium-235, 235U). A nuclear chain reaction releases several million times more energy per reaction than any chemical reaction. History Chemical chain reactions were first proposed by German chemist Max Bodenstein in 1913, and were reasonably well understood before nuclear chain reactions were proposed. It was understood that chemical chain reactions were responsible for exponentially increasing rates in reactions, such as produced in chemical explosions. The concept of a nuclear chain reaction was reportedly first hypothesized by Hungarian scientist Leó Szilárd on September 12, 1933. Szilárd that morning had been reading in a London paper of an experiment in which proton ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fission Chain Reaction
Fission, a splitting of something into two or more parts, may refer to: * Fission (biology), the division of a single entity into two or more parts and the regeneration of those parts into separate entities resembling the original * Nuclear fission Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radio ..., when the nucleus of an atom splits into smaller parts * Fission (band), a Swedish death metal band * ''Fission'' (album), by Jens Johansson See also * Fusion (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discovery Of Nuclear Fission
Nuclear fission was discovered in December 1938 by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Fission is a nuclear reaction or radioactive decay process in which the nucleus of an atom splits into two or more smaller, lighter nuclei and often other particles. The fission process often produces gamma rays and releases a very large amount of energy, even by the energetic standards of radioactive decay. Scientists already knew about alpha decay and beta decay, but fission assumed great importance because the discovery that a nuclear chain reaction was possible led to the development of nuclear power and nuclear weapons. Hahn was awarded the 1944 Nobel Prize in Chemistry for the discovery of nuclear fission. Hahn and Strassmann at the Kaiser Wilhelm Institute for Chemistry in Berlin bombarded uranium with slow neutrons and discovered that barium had been produced. Hahn suggested a bursting of the nucleus, but he was unsure of what ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chicago Pile-1
Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1, during an experiment led by Enrico Fermi. The secret development of the reactor was the first major technical achievement for the Manhattan Project, the Allied effort to create atomic bombs during World War II. Developed by the Metallurgical Laboratory at the University of Chicago, CP-1 was built under the west viewing stands of the original Stagg Field. Although the project's civilian and military leaders had misgivings about the possibility of a disastrous runaway reaction, they trusted Fermi's safety calculations and decided they could carry out the experiment in a densely populated area. Fermi described the reactor as "a crude pile of black bricks and wooden timbers". The reactor was assembled in November 1942, by a team that included Fermi, Leo Szilard (who had previously formulated an idea for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Bomb
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb types release large quantities of energy from relatively small amounts of matter. The first test of a fission ("atomic") bomb released an amount of energy approximately equal to . The first thermonuclear ("hydrogen") bomb test released energy approximately equal to . Nuclear bombs have had yields between 10 tons TNT (the W54) and 50 megatons for the Tsar Bomba (see TNT equivalent). A thermonuclear weapon weighing as little as can release energy equal to more than . A nuclear device no larger than a conventional bomb can devastate an entire city by blast, fire, and radiation. Since they are weapons of mass destruction, the proliferation of nuclear weapons is a focus of international relations policy. Nuclear weapons have been dep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nazi Germany
Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was the German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a dictatorship. Under Hitler's rule, Germany quickly became a totalitarian state where nearly all aspects of life were controlled by the government. The Third Reich, meaning "Third Realm" or "Third Empire", alluded to the Nazi claim that Nazi Germany was the successor to the earlier Holy Roman Empire (800–1806) and German Empire (1871–1918). The Third Reich, which Hitler and the Nazis referred to as the Thousand-Year Reich, ended in May 1945 after just 12 years when the Allies defeated Germany, ending World War II in Europe. On 30 January 1933, Hitler was appointed chancellor of Germany, the head of gove ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franklin D
Franklin may refer to: People * Franklin (given name) * Franklin (surname) * Franklin (class), a member of a historical English social class Places Australia * Franklin, Tasmania, a township * Division of Franklin, federal electoral division in Tasmania * Division of Franklin (state), state electoral division in Tasmania * Franklin, Australian Capital Territory, a suburb in the Canberra district of Gungahlin * Franklin River, river of Tasmania * Franklin Sound, waterway of Tasmania Canada * District of Franklin, a former district of the Northwest Territories * Franklin, Quebec, a municipality in the Montérégie region * Rural Municipality of Franklin, Manitoba * Franklin, Manitoba, an unincorporated community in the Rural Municipality of Rosedale, Manitoba * Franklin Glacier Complex, a volcano in southwestern British Columbia * Franklin Range, a mountain range on Vancouver Island, British Columbia * Franklin River (Vancouver Island), British Columbia * Franklin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics. Relativity and quantum mechanics are the two pillars of modern physics. His mass–energy equivalence formula , which arises from relativity theory, has been dubbed "the world's most famous equation". His work is also known for its influence on the philosophy of science. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory. His intellectual achievements and originality resulted in "Einstein" becoming synonymous with "genius". In 1905, a year sometimes described as his ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enrico Fermi
Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" and the "architect of the atomic bomb". He was one of very few physicists to excel in both theoretical physics and experimental physics. Fermi was awarded the 1938 Nobel Prize in Physics for his work on induced radioactivity by neutron bombardment and for the discovery of transuranium elements. With his colleagues, Fermi filed several patents related to the use of nuclear power, all of which were taken over by the US government. He made significant contributions to the development of statistical mechanics, quantum theory, and nuclear and particle physics. Fermi's first major contribution involved the field of statistical mechanics. After Wolfgang Pauli formulated his exclusion principle in 1925, Fermi followed with a paper in which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centre National De La Recherche Scientifique
The French National Centre for Scientific Research (french: link=no, Centre national de la recherche scientifique, CNRS) is the French state research organisation and is the largest fundamental science agency in Europe. In 2016, it employed 31,637 staff, including 11,137 tenured researchers, 13,415 engineers and technical staff, and 7,085 contractual workers. It is headquartered in Paris and has administrative offices in Brussels, Beijing, Tokyo, Singapore, Washington, D.C., Bonn, Moscow, Tunis, Johannesburg, Santiago de Chile, Israel, and New Delhi. From 2009 to 2016, the CNRS was ranked No. 1 worldwide by the SCImago Institutions Rankings (SIR), an international ranking of research-focused institutions, including universities, national research centers, and companies such as Facebook or Google. The CNRS ranked No. 2 between 2017 and 2021, then No. 3 in 2022 in the same SIR, after the Chinese Academy of Sciences and before universities such as Harvard University, MIT, or Stanfo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lew Kowarski
Lew Kowarski (10 February 1907, Saint Petersburg – 30 July 1979, Geneva) was a naturalized French physicist. He was a lesser-known but important contributor to nuclear science. Early life Lew Kowarski was born in Saint Petersburg to Nicholas Kowarski, a businessman and the Ukrainian singer Olga Vlassenko. Following the Bolshevik Revolution, when Lew was 12 years old, his family fled west under adventurous circumstances and settled in Vilnius (then in Poland). During his youth, Lew was a talented musician and considered a music career; however, his fingers grew too large for the keyboard. Education He received a Chemical Engineering degree from the University of Lyon and an Sc.B. and Ph.D. from the University of Paris where he carried out research on neutron counting. Research during World War II He joined Frédéric Joliot-Curie's group in 1934, where Hans von Halban came in 1937. They established in 1939 the possibility of nuclear chain reactions and nuclear energy productio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Von Halban
Hans Heinrich von Halban (24 January 1908 – 28 November 1964) was a French physicist, of Austrian- Jewish descent. Family He was descended on his father's side from Polish Jews, who left Kraków for Vienna in the 1850s. His grandfather, Heinrich Blumenstock, was a senior official in the Habsburg Empire and was ennobled by Emperor Franz Joseph I in the 1880s, taking the name of Ritter Heinrich Blumenstock von Halban. The surname Blumenstock was subsequently dropped by the family, as was the use of 'von' after the Second World War. His mother's family was from Bohemia and his great-grandfather, Moritz von Fialka, was a colonel in the Austro-Prussian War of 1866. Although converted to Catholicism, the family were never religiously observant. Hans Halban was a convinced secularist. Education and research Hans Halban was born in Leipzig and moved to Würzburg, where his father, Hans von Halban Sr. became a professor of physical chemistry. He began his studies in physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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