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Samuel T. Cohen
Samuel Theodore Cohen (January 25, 1921 – November 28, 2010) was an American physicist who is generally credited as the father of the neutron bomb. Biography Cohen's parents were Austrian Jews who emigrated from London, England. He was born on January 25, 1921, in Brooklyn and raised in New York City. He studied mathematics and physics at University of California, Los Angeles before joining the United States Army after the Japanese attack on Pearl Harbor. In 1944 he worked on the Manhattan Project in the efficiency group at Los Alamos and calculated how neutrons behaved in Fat Man, the atomic bomb that was later detonated over Nagasaki, Japan. After the war he studied for his Ph.D. at Berkeley before dropping out to join the RAND Corporation. At RAND Corporation in 1950, his work on the intensity of fallout radiation first became public when his calculations were included as a special appendix in Samuel Glasstone's book ''The Effects of Atomic Weapons''. Cohen was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brooklyn
Brooklyn () is a borough of New York City, coextensive with Kings County, in the U.S. state of New York. Kings County is the most populous county in the State of New York, and the second-most densely populated county in the United States, behind New York County (Manhattan). Brooklyn is also New York City's most populous borough,2010 Gazetteer for New York State . Retrieved September 18, 2016. with 2,736,074 residents in 2020. Named after the Dutch village of Breukelen, Brooklyn is located on the w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wall Street Journal
''The Wall Street Journal'' is an American business-focused, international daily newspaper based in New York City, with international editions also available in Chinese and Japanese. The ''Journal'', along with its Asian editions, is published six days a week by Dow Jones & Company, a division of News Corp. The newspaper is published in the broadsheet format and online. The ''Journal'' has been printed continuously since its inception on July 8, 1889, by Charles Dow, Edward Jones, and Charles Bergstresser. The ''Journal'' is regarded as a newspaper of record, particularly in terms of business and financial news. The newspaper has won 38 Pulitzer Prizes, the most recent in 2019. ''The Wall Street Journal'' is one of the largest newspapers in the United States by circulation, with a circulation of about 2.834million copies (including nearly 1,829,000 digital sales) compared with ''USA Today''s 1.7million. The ''Journal'' publishes the luxury news and lifestyle magazine ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hans Bethe
Hans Albrecht Bethe (; July 2, 1906 – March 6, 2005) was a German-American theoretical physicist who made major contributions to nuclear physics, astrophysics, quantum electrodynamics, and solid-state physics, and who won the 1967 Nobel Prize in Physics for his work on the theory of stellar nucleosynthesis. For most of his career, Bethe was a professor at Cornell University.Available at www.JamesKeckCollectedWorks.or are the class notes taken by one of his students at Cornell from the graduate courses on Nuclear Physics and on Applications of Quantum Mechanics he taught in the spring of 1947. During World War II, he was head of the Theoretical Division at the secret Los Alamos National Laboratory, Los Alamos laboratory that developed the first atomic bombs. There he played a key role in calculating the critical mass of the weapons and developing the theory behind the implosion method used in both the Trinity test and the "Fat Man" weapon dropped on Nagasaki in August 1945. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten Carbide
Tungsten carbide (chemical formula: WC) is a chemical compound (specifically, a carbide) containing equal parts of tungsten and carbon atoms. In its most basic form, tungsten carbide is a fine gray powder, but it can be pressed and formed into shapes through sintering for use in industrial machinery, cutting tools, chisels, abrasives, armor-piercing shells and jewelry. Tungsten carbide is approximately twice as stiff as steel, with a Young's modulus of approximately 530–700 GPa, and is double the density of steel—nearly midway between that of lead and gold. It is comparable with corundum (α-) in hardness and can be polished and finished only with abrasives of superior hardness such as cubic boron nitride and diamond powder, wheels and compounds. Naming Historically referred to as Wolfram, ''Wolf Rahm'', wolframite ore was then later carburized and cemented with a binder creating a composite now called "tungsten carbide". Tungsten is Swedish for "heavy stone". Col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Reflector
A neutron reflector is any material that reflects neutrons. This refers to elastic scattering rather than to a specular reflection. The material may be graphite, beryllium, steel, tungsten carbide, gold, or other materials. A neutron reflector can make an otherwise subcritical mass of fissile material critical, or increase the amount of nuclear fission that a critical or supercritical mass will undergo. Such an effect was exhibited twice in accidents involving the Demon Core, a subcritical plutonium pit that went critical in two separate fatal incidents when the pit's surface was momentarily surrounded by too much neutron reflective material. Nuclear reactors In a uranium graphite chain reacting pile, the critical size may be considerably reduced by surrounding the pile with a layer of graphite, since such an envelope reflects many neutrons back into the pile. To obtain a 30-year life span, the SSTAR nuclear reactor design calls for a moveable neutron reflector to be pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Deuteride
Lithium hydride is an inorganic compound with the formula Li H. This alkali metal hydride is a colorless solid, although commercial samples are grey. Characteristic of a salt-like (ionic) hydride, it has a high melting point, and it is not soluble but reactive with all protic organic solvents. It is soluble and nonreactive with certain molten salts such as lithium fluoride, lithium borohydride, and sodium hydride. With a molar mass of 7.95 g/mol, it is the lightest ionic compound. Physical properties LiH is a diamagnetic and an ionic conductor with a conductivity gradually increasing from at 443 °C to 0.18 Ω−1cm−1 at 754 °C; there is no discontinuity in this increase through the melting point. The dielectric constant of LiH decreases from 13.0 (static, low frequencies) to 3.6 (visible-light frequencies). LiH is a soft material with a Mohs hardness of 3.5. Its compressive creep (per 100 hours) rapidly increases from 100% at 475 °C, meaning that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium-238
Uranium-238 (238U or U-238) is the most common isotope of uranium found in nature, with a relative abundance of 99%. Unlike uranium-235, it is non-fissile, which means it cannot sustain a chain reaction in a thermal-neutron reactor. However, it is fissionable by fast neutrons, and is ''fertile'', meaning it can be transmuted to fissile plutonium-239. 238U cannot support a chain reaction because inelastic scattering reduces neutron energy below the range where fast fission of one or more next-generation nuclei is probable. Doppler broadening of 238U's neutron absorption resonances, increasing absorption as fuel temperature increases, is also an essential negative feedback mechanism for reactor control. Around 99.284% of natural uranium's mass is uranium-238, which has a half-life of 1.41 seconds (4.468 years, or 4.468 billion years). Due to its natural abundance and half-life relative to other radioactive elements, 238U produces ~40% of the radioactive heat produced within th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navajo (atomic Test)
The Navajo (; British English: Navaho; nv, Diné or ') are a Native Americans in the United States, Native American people of the Southwestern United States. With more than 399,494 enrolled tribal members , the Navajo Nation is the largest federally recognized tribe in the United States; additionally, the Navajo Nation has the largest Indian reservation, reservation in the country. The reservation straddles the Four Corners region and covers more than 27,325 square miles (70,000 square km) of land in Arizona, Utah, and New Mexico. The Navajo Reservation is slightly larger than the state of West Virginia. The Navajo language is spoken throughout the region, and most Navajos also speak English. The states with the largest Navajo populations are Arizona (140,263) and New Mexico (108,306). More than three-fourths of the enrolled Navajo population resides in these two states. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dwight D
Dwight may refer to: People * Dwight (given name) * Dwight D. Eisenhower (1890–1969), 34th president of the United States and former military officer *New England Dwight family of American educators, military and political leaders, and authors * Ed Dwight (born 1933), American test pilot, participated in astronaut training program * Mabel Dwight (1875–1955), American artist * Elton John (born Reginald Dwight in 1947), English singer, songwriter and musician Places Canada * Dwight, Ontario, village in the township of Lake of Bays, Ontario United States * Dwight (neighborhood), part of an historic district in New Haven, Connecticut * Dwight, Illinois, village in Livingston and Grundy counties * Dwight, Kansas, city in Morris County * Dwight, Michigan, an unincorporated community * Dwight, Nebraska, village in Butler County * Dwight, North Dakota, city in Richland County * Dwight Township, Livingston County, Illinois * Dwight Township, Michigan Institutions * Dwight Correctional ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MGM-52 Lance
The MGM-52 Lance was a mobile field artillery tactical surface-to-surface missile (tactical ballistic missile) system used to provide both nuclear and conventional fire support to the United States Army. The missile's warhead was developed at Lawrence Livermore National Laboratory. It was replaced by MGM-140 ATACMS, which was initially intended to likewise have a nuclear capability during the Cold War. Deployment The first Lance missiles were deployed in 1972, replacing (together with the US-Navy's nuclear-tipped RIM-2D and RIM-8E/B/D) the earlier Honest John rocket and Sergeant SRBM ballistic missile, greatly reducing the weight and bulk of the system, while improving both accuracy and mobility. A Lance battery (two fire units) consisted of two M752 launchers (one missile each) and two M688 auxiliary vehicles (two missiles each), for a total six missiles; the firing rate per unit was approximately three missiles per hour. The launch vehicles were also able to carry and launc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ronald Reagan
Ronald Wilson Reagan ( ; February 6, 1911June 5, 2004) was an American politician, actor, and union leader who served as the 40th president of the United States from 1981 to 1989. He also served as the 33rd governor of California from 1967 to 1975, after having a career in entertainment. Reagan was born in Tampico, Illinois. He graduated from Eureka College in 1932 and began to work as a sports announcer in Iowa. In 1937, Reagan moved to California, where he found Ronald Reagan filmography, work as a film actor. From 1947 to 1952, Reagan served as the president of the Screen Actors Guild, working to Hollywood blacklist, root out alleged communist influence within it. In the 1950s, he moved to a career in television and became a spokesman for General Electric. From 1959 to 1960, he again served as the guild's president. In 1964, his speech "A Time for Choosing" earned him national attention as a new conservative figure. Building a network of supporters, Reagan was 1966 Califo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vietnam War
The Vietnam War (also known by #Names, other names) was a conflict in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. It was the second of the Indochina Wars and was officially fought between North Vietnam and South Vietnam. The north was supported by the Soviet Union, China, and other communist states, while the south was United States in the Vietnam War, supported by the United States and other anti-communism, anti-communist Free World Military Forces, allies. The war is widely considered to be a Cold War-era proxy war. It lasted almost 20 years, with direct U.S. involvement ending in 1973. The conflict also spilled over into neighboring states, exacerbating the Laotian Civil War and the Cambodian Civil War, which ended with all three countries becoming communist states by 1975. After the French 1954 Geneva Conference, military withdrawal from Indochina in 1954 – following their defeat in the First Indochina War – the Viet Minh to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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