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Iron-57
Naturally occurring iron (26Fe) consists of four stable isotopes: 5.845% of 54Fe (possibly radioactive with a half-life over years), 91.754% of 56Fe, 2.119% of 57Fe and 0.286% of 58Fe. There are 24 known radioactive isotopes, the most stable of which are 60Fe (half-life 2.6 million years) and 55Fe (half-life 2.7 years). Much of the past work on measuring the isotopic composition of Fe has centered on determining 60Fe variations due to processes accompanying nucleosynthesis (i.e., meteorite studies) and ore formation. In the last decade however, advances in mass spectrometry technology have allowed the detection and quantification of minute, naturally occurring variations in the ratios of the stable isotopes of iron. Much of this work has been driven by the Earth and planetary science communities, although applications to biological and industrial systems are beginning to emerge. List of isotopes , - , rowspan=2, 45Fe , rowspan=2 style="text-align:right" , 26 , rowspan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mössbauer Spectroscopy
Mössbauer spectroscopy is a spectroscopic technique based on the Mössbauer effect. This effect, discovered by Rudolf Mössbauer (sometimes written "Moessbauer", German: "Mößbauer") in 1958, consists of the nearly recoil-free emission and absorption of nuclear gamma rays in solids. The consequent nuclear spectroscopy method is exquisitely sensitive to small changes in the chemical environment of certain nuclei. Typically, three types of nuclear interactions may be observed: the isomer shift due to differences in nearby electron densities (also called the chemical shift in older literature), quadrupole splitting due to atomic-scale electric field gradients; and magnetic Zeeman splitting due to non-nuclear magnetic fields. Due to the high energy and extremely narrow line widths of nuclear gamma rays, Mössbauer spectroscopy is a highly sensitive technique in terms of energy (and hence frequency) resolution, capable of detecting changes of just a few parts in 1011. It is a me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Redshift
In physics and general relativity, gravitational redshift (known as Einstein shift in older literature) is the phenomenon that electromagnetic waves or photons travelling out of a gravitational well (seem to) lose energy. This loss of energy corresponds to a decrease in the wave frequency and increase in the wavelength, known more generally as a '' redshift''. The opposite effect, in which photons (seem to) gain energy when travelling into a gravitational well, is known as a gravitational blueshift (a type of ''blueshift''). The effect was first described by Einstein in 1907, eight years before his publication of the full theory of relativity. Gravitational redshift can be interpreted as a consequence of the equivalence principle (that gravity and acceleration are equivalent and the redshift is caused by the Doppler effect) or as a consequence of the mass-energy equivalence and conservation of energy ('falling' photons gain energy), though there are numerous subtleties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Observationally Stable
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay. When such nuclides are referred to in relation to specific elements, they are usually termed stable isotopes. The 80 elements with one or more stable isotopes comprise a total of 251 nuclides that have not been known to decay using current equipment (see list at the end of this article). Of these 80 elements, 26 have only one stable isotope; they are thus termed monoisotopic. The rest have more than one stable isotope. Tin has ten stable isotopes, the largest number of stable isotopes known for an element. Definition of stability, and naturally occurring nuclides Most naturally occurring nuclides are stable (about 251; see list at the end of this article), and about 34 more (total of 286) are known to be radioactive with sufficiently long half-lives (also known) to occur primordially. If the half-life of a nuclide is comparable to, or greater ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in front of oxygen (32.1% and 30.1%, respectively), forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust. In its metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching or higher, about higher than that required to smelt copper. Humans started to master that process in Eurasia during the 2nd millennium BCE and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE. That event is considered the transition from the Bronze Age to the Iron A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron-56
Iron-56 (56Fe) is the most common isotope of iron. About 91.754% of all iron is iron-56. Of all nuclides, iron-56 has the lowest mass per nucleon. With 8.8 MeV binding energy per nucleon, iron-56 is one of the most tightly bound nuclei. Nickel-62, a relatively rare isotope of nickel, has a higher nuclear binding energy per nucleon; this is consistent with having a higher mass-per-nucleon because nickel-62 has a greater proportion of neutrons, which are slightly more massive than protons. (See the nickel-62 article for more). Light elements undergoing nuclear fusion and heavy elements undergoing nuclear fission release energy as their nucleons bind more tightly, so 62Ni might be expected to be common. However, during nucleosynthesis in stars the competition between photodisintegration and alpha capturing causes more 56Ni to be produced than 62Ni (56Fe is produced later in the star's ejection shell as 56Ni decays). Production of these elements has decreased considerably f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HyperPhysics
''HyperPhysics'' is an educational website about physics topics. The information architecture of the website is based on HyperCard, the platform on which the material was originally developed, and a thesaurus organization, with thousands of controlled links and usual trees organizing topics from general to specific. It also exploits concept maps to facilitate smooth navigation. ''HyperPhysics'' is hosted by Georgia State University and authored by Georgia State faculty member Dr. Rod Nave. Various teaching and education facilitators make use of ''HyperPhysics'' material through projects and organizations, and also publishers which use SciLinks. Topics Physics Various areas of physics are accessible through broad categories. * Astrophysics * Condensed matter * Electricity and magnetism * Heat and thermodynamics * Light and vision * Mechanics * Nuclear physics * Quantum physics * Relativity * Sound and hearing Mathematics Related applied mathematics are also covered. *Algebra * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Resonance Vibrational Spectroscopy
Nuclear resonance vibrational spectroscopy is a synchrotron-based technique that probes vibrational energy levels. The technique, often called NRVS, is specific for samples that contain nuclei that respond to Mössbauer spectroscopy, most commonly iron. The method exploits the high resolution offered by synchrotron light sources, which enables the resolution of vibrational fine structure, especially those vibrations that are coupled to the position of the Fe centre(s). The method is popularly applied to problems in bioinorganic chemistry, materials science, and geophysics Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' som .... A novel aspect of the method is the ability to determine the 3D-trajectory of iron atoms within vibrational modes, providing a unique appraisal of DFT-predicti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metallicity
In astronomy, metallicity is the abundance of elements present in an object that are heavier than hydrogen and helium. Most of the normal physical matter in the Universe is either hydrogen or helium, and astronomers use the word ''"metals"'' as a convenient short term for ''"all elements except hydrogen and helium"''. This word-use is distinct from the conventional chemical or physical definition of a metal as an electrically conducting solid. Stars and nebulae with relatively high abundances of heavier elements are called "metal-rich" in astrophysical terms, even though many of those elements are nonmetals in chemistry. The presence of heavier elements hails from stellar nucleosynthesis, where the majority of elements heavier than hydrogen and helium in the Universe (''metals'', hereafter) are formed in the cores of stars as they evolve. Over time, stellar winds and supernovae deposit the metals into the surrounding environment, enriching the interstellar medium and providing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Physics
The ''American Journal of Physics'' is a monthly, peer-reviewed scientific journal published by the American Association of Physics Teachers and the American Institute of Physics. The editor-in-chief is Beth Parks of Colgate University."Current Frequency: Monthly, 2002; and Former Frequency varies, 1940-2001" Confirmation of Editor, ISSN, CODEN, and other relevant information. Aims and scope The focus of this journal is undergraduate and graduate level physics. The intended audience is college and university physics teachers and students. Coverage includes current research in physics, instructional laboratory equipment, laboratory demonstrations, teaching methodologies, lists of resources, and book reviews. In addition, historical, philosophical and cultural aspects of physics are also covered. According to the 2021 Journal Citation Reports from Clarivate, this journal has a 2020 impact factor of 1.022. History The former title of this journal was ''American Physics Teacher'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nickel-62
Nickel-62 is an isotope of nickel having 28 protons and 34 neutrons. It is a stable isotope, with the highest binding energy per nucleon of any known nuclide (8.7945 MeV). It is often stated that 56Fe is the "most stable nucleus", but only because 56Fe has the lowest ''mass'' per nucleon (not binding energy per nucleon) of all nuclides. The lower mass per nucleon of 56Fe is possible because 56Fe has 26/56 ≈ 46.43% protons, while 62Ni has only 28/62 ≈ 45.16% protons; and the larger fraction of lighter protons in 56Fe lowers its mean mass-per-nucleon ratio in a way that has no effect on its binding energy. Properties The high binding energy of nickel isotopes in general makes nickel an "end product" of many nuclear reactions (including neutron capture reactions) throughout the universe and accounts for the high relative abundance of nickel—although most of the nickel in space (and thus produced by supernova explosions) is nickel-58 (the most common isotope) and nickel- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Binding Energy
Nuclear binding energy in experimental physics is the minimum energy that is required to disassemble the atomic nucleus, nucleus of an atom into its constituent protons and neutrons, known collectively as nucleons. The binding energy for stable nuclei is always a positive number, as the nucleus must gain energy for the nucleons to move apart from each other. Nucleons are attracted to each other by the strong nuclear force. In theoretical nuclear physics, the nuclear binding energy is considered a negative number. In this context it represents the energy of the nucleus relative to the energy of the constituent nucleons when they are infinitely far apart. Both the experimental and theoretical views are equivalent, with slightly different emphasis on what the binding energy means. The mass of an atomic nucleus is less than the sum of the individual masses of the free Wiktionary:constituent, constituent protons and neutrons. The difference in mass can be calculated by the Mass–energ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
