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Beijing Electron–Positron Collider II
The Beijing Electron–Positron Collider II (BEPC II) is a Chinese electron–positron collider, a type of particle accelerator, located in Shijingshan District, Beijing, People's Republic of China. It has been in operation since 2008 and has a circumference of 240.4 m. It was intended as a charm factory and continues the role of CLEO-c detector. The center of mass energy can go up to 4.6 GeV with a design luminosity of 1033 cm−2·s−1. Operations began in summer 2008 and the machine has run at multiple energies. History The construction of the original Beijing Electron Positron Collider was approved in 1983, as China was emerging from the Cultural Revolution, based on a proposal developed by Xie Jialin, who went on to oversee the construction of the machine. The construction of this collider was considered so important that then vice-premier Deng Xiaoping attended the groundbreaking in 1984 and returned in 1988 as the machine neared operation. The origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function assigning a vector to each point of space ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science And Technology In The People's Republic Of China
Science and technology in China have developed rapidly during the 1980s to 2010s, and major scientific and technological achievements have been made since the 1980s. From the 1980s to the 1990s, the Chinese government successively launched the " 863 Plan" and the "Strategy for Rejuvenating the Country through Science and Education", which greatly promoted the development and progress of China's science and technology. The Chinese government has placed emphasis through funding, reform, and societal status on science and technology as a fundamental part of the socio-economic development of the country as well as for national prestige. China has made rapid advances in areas such as education, infrastructure, high-tech manufacturing, academic publishing, patents, and commercial applications and is now in some areas and by some measures a world leader. China is now increasingly targeting indigenous innovation and aims to reform remaining weaknesses. Per the Global Innovation Inde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Experiments
In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion. The term ''particle'' is rather general in meaning, and is refined as needed by various scientific fields. Anything that is composed of particles may be referred to as being particulate. However, the noun '' particulate'' is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation. Conceptual properties Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Physics Facilities
In the physical sciences, a particle (or corpuscule in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from subatomic particles like the electron, to microscopic particles like atoms and molecules, to macroscopic particles like powders and other granular materials. Particles can also be used to create scientific models of even larger objects depending on their density, such as humans moving in a crowd or celestial bodies in motion. The term ''particle'' is rather general in meaning, and is refined as needed by various scientific fields. Anything that is composed of particles may be referred to as being particulate. However, the noun '' particulate'' is most frequently used to refer to pollutants in the Earth's atmosphere, which are a suspension of unconnected particles, rather than a connected particle aggregation. Conceptual properties T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Projects Established In 2008
A project is any undertaking, carried out individually or collaboratively and possibly involving research or design, that is carefully planned to achieve a particular goal. An alternative view sees a project managerially as a sequence of events: a "set of interrelated tasks to be executed over a fixed period and within certain cost and other limitations". A project may be a temporary (rather than a permanent) social system ( work system), possibly staffed by teams (within or across organizations) to accomplish particular tasks under time constraints. A project may form a part of wider programme management or function as an ''ad hoc'' system. Note that open-source software "projects" or artists' musical "projects" (for example) may lack defined team-membership, precise planning and/or time-limited durations. Overview The word ''project'' comes from the Latin word ''projectum'' from the Latin verb ''proicere'', "before an action," which in turn comes from ''pro-'', which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2008 Establishments In China
8 (eight) is the natural number following 7 and preceding 9. In mathematics 8 is: * a composite number, its proper divisors being , , and . It is twice 4 or four times 2. * a power of two, being 2 (two cubed), and is the first number of the form , being an integer greater than 1. * the first number which is neither prime nor semiprime. * the base of the octal number system, which is mostly used with computers. In octal, one digit represents three bits. In modern computers, a byte is a grouping of eight bits, also called an wikt:octet, octet. * a Fibonacci number, being plus . The next Fibonacci number is . 8 is the only positive Fibonacci number, aside from 1, that is a perfect cube. * the only nonzero perfect power that is one less than another perfect power, by Catalan conjecture, Mihăilescu's Theorem. * the order of the smallest non-abelian group all of whose subgroups are normal. * the dimension of the octonions and is the highest possible dimension of a normed divisio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron–positron Annihilation
Electron–positron annihilation occurs when an electron () and a positron (, the electron's antiparticle) collide. At low energies, the result of the collision is the annihilation of the electron and positron, and the creation of energetic photons: : + → + At high energies, other particles, such as B mesons or the W and Z bosons, can be created. All processes must satisfy a number of conservation laws, including: *Conservation of electric charge. The net charge before and after is zero. *Conservation of linear momentum and total energy. This forbids the creation of a single photon. However, in quantum field theory this process is allowed; see examples of annihilation. *Conservation of angular momentum. *Conservation of total (i.e. net) lepton number, which is the number of leptons (such as the electron) minus the number of antileptons (such as the positron); this can be described as a conservation of (net) matter law. As with any two charge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Super Charm-Tau Factory
Super Charm-Tau factory (SCT) is an electron–positron collider being designed and built by Budker Institute of Nuclear Physics in Novosibirsk. Its main goal is to study the CP-violation in the processes involving charmed hadrons, to investigate decays of the τ-lepton as well as to search for new forms of matter: glueballs, dark matter, etc. In the SCT the center of mass energy of colliding electrons and positrons will be 2–6 GeV while the luminosity will reach as high as . The electrons will be partially polarized. The synchrotron will be operating for 10 years. The particle registration and measurements will done using a universal high performance magnetic detector with the field strength of 1–1.5 Tesla. The SCT project is one Megascience class projects being built in Russia. See also *Beijing Electron–Positron Collider II *Belle II *PANDA experiment The PANDA experiment is a planned particle physics experiment at the Facility for Antiproton and Ion Research in D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Electron–Positron Collider
The Large Electron–Positron Collider (LEP) was one of the largest particle accelerators ever constructed. It was built at CERN, a multi-national centre for research in nuclear and particle physics near Geneva, Switzerland. LEP collided electrons with positrons at energies that reached 209 GeV. It was a circular collider with a circumference of 27 kilometres built in a tunnel roughly 100 m (300 ft) underground and passing through Switzerland and France. LEP was used from 1989 until 2000. Around 2001 it was dismantled to make way for the Large Hadron Collider, which re-used the LEP tunnel. To date, LEP is the most powerful accelerator of leptons ever built. Collider background LEP was a circular lepton collider – the most powerful such ever built. For context, modern colliders can be generally categorized based on their shape (circular or linear) and on what types of particles they accelerate and collide (leptons or hadrons). Leptons are point particles and are rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caesium Iodide
Caesium iodide or cesium iodide (chemical formula CsI) is the ionic compound of caesium and iodine. It is often used as the input phosphor of an X-ray image intensifier tube found in fluoroscopy equipment. Caesium iodide photocathodes are highly efficient at extreme ultraviolet wavelengths. Synthesis and structure Bulk caesium iodide crystals have the cubic CsCl crystal structure, but the structure type of nanometer-thin CsI films depends on the substrate material – it is CsCl for mica and NaCl for LiF, NaBr and NaCl substrates. Caesium iodide atomic chains can be grown inside double-wall carbon nanotubes. In such chains I atoms appear brighter than Cs atoms in electron micrographs despite having a smaller mass. This difference was explained by the charge difference between Cs atoms (positive), inner nanotube walls (negative) and I atoms (negative). As a result, Cs atoms are attracted to the walls and vibrate more strongly than I atoms, which are pushed toward the nanotube ax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calorimeter
A calorimeter is an object used for calorimetry, or the process of measuring the heat of chemical reactions or physical changes as well as heat capacity. Differential scanning calorimeters, isothermal micro calorimeters, titration calorimeters and accelerated rate calorimeters are among the most common types. A simple calorimeter just consists of a thermometer attached to a metal container full of water suspended above a combustion chamber. It is one of the measurement devices used in the study of thermodynamics, chemistry, and biochemistry. To find the enthalpy change per mole of a substance A in a reaction between two substances A and B, the substances are separately added to a calorimeter and the initial and final temperatures (before the reaction has started and after it has finished) are noted. Multiplying the temperature change by the mass and specific heat capacities of the substances gives a value for the energy given off or absorbed during the reaction. Dividing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
