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Double Magic
In nuclear physics, a magic number is a number of nucleons (either protons or neutrons, separately) such that they are arranged into complete shells within the atomic nucleus. As a result, atomic nuclei with a "magic" number of protons or neutrons are much more stable than other nuclei. The seven most widely recognized magic numbers as of 2019 are 2, 8, 20, 28, 50, 82, and 126. For protons, this corresponds to the elements helium, oxygen, calcium, nickel, tin, lead, and the hypothetical unbihexium, although 126 is so far only known to be a magic number for neutrons. Atomic nuclei consisting of such a magic number of nucleons have a higher average binding energy per nucleon than one would expect based upon predictions such as the semi-empirical mass formula and are hence more stable against nuclear decay. The unusual stability of isotopes having magic numbers means that transuranium elements could theoretically be created with extremely large nuclei and yet not be subject to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Table Isotopes En
Table may refer to: * Table (database), how the table data arrangement is used within the databases * Table (furniture), a piece of furniture with a flat surface and one or more legs * Table (information), a data arrangement with rows and columns * Table (landform), a flat area of land * Table (parliamentary procedure) * Table (sports), a ranking of the teams in a sports league * Tables (board game) * Mathematical table * Tables of the skull, a term for the flat bones * Table, surface of the sound board (music) of a string instrument * ''Al-Ma'ida'', the fifth ''surah'' of the Qur'an, occasionally translated as “The Table” * Calligra Tables, a spreadsheet application * Water table See also * Spreadsheet, a computer application * Table cut, a type of diamond cut * The Table (other) * Table Mountain (other) * Table Rock (other) Table Rock may refer to: Canada * Table Rock, Niagara Falls, a former rock formation ** Table Rock Welcome Centre, a reta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Decay
Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is considered ''radioactive''. Three of the most common types of decay are Alpha decay, alpha, Beta decay, beta, and Gamma ray, gamma decay. The weak force is the Fundamental interactions, mechanism that is responsible for beta decay, while the other two are governed by the electromagnetic force, electromagnetic and nuclear forces. Radioactive decay is a randomness, random process at the level of single atoms. According to quantum mechanics, quantum theory, it is impossible to predict when a particular atom will decay, regardless of how long the atom has existed. However, for a significant number of identical atoms, the overall decay rate can be expressed as a decay constant or as a half-life. The half-lives of radioactive atoms have a huge range: f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxygen-16
Oxygen-16 (symbol: 16O or ) is a nuclide. It is a stable isotope of oxygen, with 8 neutrons and 8 protons in its nucleus, and when not ionized, 8 electrons orbiting the nucleus. Oxygen-16 has a mass of . It is the most abundant isotope of oxygen and accounts for 99.757% of oxygen's natural abundance. The relative and absolute abundances of oxygen-16 are high because it is a principal product of stellar evolution and because it is a primordial isotope, meaning it can be made by stars that were initially made exclusively of hydrogen. Most oxygen-16 is synthesized at the end of the helium fusion process in stars; the triple-alpha process creates carbon-12, which captures an additional helium-4 to make oxygen-16. It is also created by the neon-burning process. Oxygen-16 is doubly magic. Solid samples (organic and inorganic) for oxygen-16 studies are usually stored in silver cups and measured with pyrolysis and mass spectrometry. Researchers need to avoid improper or prolo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium-4
Helium-4 () is a stable isotope of the element helium. It is by far the more abundant of the two naturally occurring isotopes of helium, making up about 99.99986% of the helium on Earth. Its nucleus is identical to an alpha particle, and consists of two protons and two neutrons. Helium-4 makes up about one quarter of the ordinary matter in the universe by mass, with almost all of the rest being hydrogen. While nuclear fusion in stars also produces helium-4, most of the helium-4 in the Sun and in the universe is thought to have been produced during the Big Bang, known as " primordial helium". However, primordial helium-4 is largely absent from the Earth, having escaped during the high-temperature phase of Earth's formation. On Earth, most naturally occurring helium-4 is produced by the alpha decay of heavy elements in the Earth's crust, after the planet cooled and solidified. When liquid helium-4 is cooled to below , it becomes a superfluid, with properties very different from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize In Physics
The Nobel Prize in Physics () is an annual award given by the Royal Swedish Academy of Sciences for those who have made the most outstanding contributions to mankind in the field of physics. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895 and awarded since 1901, the others being the Nobel Prize in Chemistry, Nobel Prize in Literature, Nobel Peace Prize, and Nobel Prize in Physiology or Medicine. Physics is traditionally the first award presented in the Nobel Prize ceremony. The prize consists of a medal along with a diploma and a certificate for the monetary award. The front side of the medal displays the same profile of Alfred Nobel depicted on the medals for Physics, Chemistry, and Literature. The first Nobel Prize in Physics was awarded to German physicist Wilhelm Röntgen in recognition of the extraordinary services he rendered by the discovery of X-rays. This award is administered by the Nobel Foundation and is widely regarded as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Shell Model
In nuclear physics, atomic physics, and nuclear chemistry, the nuclear shell model utilizes the Pauli exclusion principle to model the structure of atomic nuclei in terms of energy levels. The first shell model was proposed by Dmitri Ivanenko (together with E. Gapon) in 1932. The model was developed in 1949 following independent work by several physicists, most notably Maria Goeppert Mayer and J. Hans D. Jensen, who received the 1963 Nobel Prize in Physics for their contributions to this model, and Eugene Wigner, who received the Nobel Prize alongside them for his earlier groundlaying work on the atomic nuclei. The nuclear shell model is partly analogous to the atomic shell model, which describes the arrangement of electrons in an atom, in that a filled shell results in better stability. When adding nucleons (protons and neutrons) to a nucleus, there are certain points where the binding energy of the next nucleon is significantly less than the last one. This observation th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liquid Drop Model
In nuclear physics, the semi-empirical mass formula (SEMF; sometimes also called the Weizsäcker formula, Bethe–Weizsäcker formula, or Bethe–Weizsäcker mass formula to distinguish it from the Bethe–Weizsäcker process) is used to approximate the mass of an atomic nucleus from its number of protons and neutrons. As the name suggests, it is based partly on theory and partly on empirical measurements. The formula represents the liquid-drop model proposed by George Gamow, which can account for most of the terms in the formula and gives rough estimates for the values of the coefficients. It was first formulated in 1935 by German physicist Carl Friedrich von Weizsäcker, and although refinements have been made to the coefficients over the years, the structure of the formula remains the same today. The formula gives a good approximation for atomic masses and thereby other effects. However, it fails to explain the existence of lines of greater binding energy at certain numbers of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eugene Wigner
Eugene Paul Wigner (, ; November 17, 1902 – January 1, 1995) was a Hungarian-American theoretical physicist who also contributed to mathematical physics. He received the Nobel Prize in Physics in 1963 "for his contributions to the theory of the atomic nucleus and the elementary particles, particularly through the discovery and application of fundamental symmetry principles". A graduate of the Technical Hochschule Berlin (now Technische Universität Berlin), Wigner worked as an assistant to Karl Weissenberg and Richard Becker (physicist), Richard Becker at the Max Planck Institute for Physics, Kaiser Wilhelm Institute in Berlin, and David Hilbert at the University of Göttingen. Wigner and Hermann Weyl were responsible for introducing group theory into physics, particularly the theory of symmetry in physics. Along the way he performed ground-breaking work in pure mathematics, in which he authored a number of mathematical theorems. In particular, Wigner's theorem is a cornerstone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maria Goeppert Mayer
Maria Goeppert Mayer (; ; June 28, 1906 – February 20, 1972) was a German-American theoretical physicist who shared the 1963 Nobel Prize in Physics with J. Hans D. Jensen and Eugene Wigner. One half of the prize was awarded jointly to Goeppert Mayer and Jensen for their model of the atomic nucleus. She was the second woman to win a Nobel Prize in Physics, the first being Marie Curie in 1903. In 1986, the Maria Goeppert-Mayer Award for early-career women physicists was established in her honor. A graduate of the University of Göttingen, Goeppert Mayer wrote her doctoral thesis on the theory of possible two-photon absorption by atoms. At the time, the chances of experimentally verifying her thesis seemed remote, but the development of the laser in the 1960s later permitted this. Today, the unit for the two-photon absorption cross section is named the Goeppert Mayer (GM) unit. Maria Goeppert married chemist Joseph Edward Mayer and moved to the United States, where he was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhattan Project
The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the project was directed by Major General Leslie Groves of the United States Army Corps of Engineers, U.S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the bombs. The Army program was designated the Manhattan District, as its first headquarters were in Manhattan; the name gradually superseded the official codename, Development of Substitute Materials, for the entire project. The project absorbed its earlier British counterpart, Tube Alloys, and subsumed the program from the American civilian Office of Scientific Research and Development. The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$2 billion (equivalent to about $ b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maria Goeppert-Mayer Portrait
Maria may refer to: People * Mary, mother of Jesus * Maria (given name), a popular given name in many languages Place names Extraterrestrial * 170 Maria, a Main belt S-type asteroid discovered in 1877 * Lunar maria (plural of ''mare''), large, dark basaltic plains on Earth's Moon Terrestrial *Maria, Maevatanana, Madagascar * Maria, Quebec, Canada * Maria, Siquijor, the Philippines * María, Spain, in Andalusia * Îles Maria, French Polynesia *María de Huerva, Aragon, Spain * Villa Maria (other) Arts, entertainment, and media Films * ''Maria'' (1947 film), Swedish film * ''Maria'' (1975 film), Swedish film * ''Maria'' (2003 film), Romanian film * ''Maria'' (2019 film), Filipino film * ''Maria'' (2021 film), Canadian film directed by Alec Pronovost *'' Being Maria'', 2024 French film released as ''Maria'' in France * ''Maria'' (2024 film), American film * ''Maria'' (Sinhala film), Sri Lankan upcoming film Literature * ''María'' (novel), an 1867 novel by Jorge Isaacs * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Binomial Coefficient
In mathematics, the binomial coefficients are the positive integers that occur as coefficients in the binomial theorem. Commonly, a binomial coefficient is indexed by a pair of integers and is written \tbinom. It is the coefficient of the term in the polynomial expansion of the binomial power ; this coefficient can be computed by the multiplicative formula : \binom nk = \frac, which using factorial notation can be compactly expressed as : \binom = \frac. For example, the fourth power of is : \begin (1 + x)^4 &= \tbinom x^0 + \tbinom x^1 + \tbinom x^2 + \tbinom x^3 + \tbinom x^4 \\ &= 1 + 4x + 6 x^2 + 4x^3 + x^4, \end and the binomial coefficient \tbinom =\tfrac = \tfrac = 6 is the coefficient of the term. Arranging the numbers \tbinom, \tbinom, \ldots, \tbinom in successive rows for gives a triangular array called Pascal's triangle, satisfying the recurrence relation : \binom = \binom + \binom . The binomial coefficients occur in many areas of mathematics, and espe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
