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Comet Encke
Comet Encke , or Encke's Comet (official designation: 2P/Encke), is a periodic comet that completes an orbit of the Sun once every 3.3 years. (This is the shortest period of a reasonably bright comet; the faint main-belt comet 311P/PanSTARRS has a period of 3.2 years.) Encke was first recorded by Pierre Méchain on 17 January 1786, but it was not recognized as a periodic comet until 1819 when its orbit was computed by Johann Franz Encke. Like Halley's Comet, it is unusual in its being named after the calculator of its orbit rather than its discoverer. Like most comets, it has a very low albedo, reflecting only 4.6% of the light its comet nucleus, nucleus receives, although comets generate a large coma (cometary), coma and tail that can make them much more visible during their perihelion (closest approach to the Sun). The diameter of the nucleus of Encke's Comet is 4.8 km. Discovery As its official designation implies, Encke's Comet was the first periodic comet discovered af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-photon Excitation Microscopy
Two-photon excitation microscopy (TPEF or 2PEF) is a fluorescence imaging technique that allows imaging of living tissue up to about one millimeter in thickness, with 0.64 μm lateral and 3.35 μm axial spatial resolution. Unlike traditional fluorescence microscopy, in which the excitation wavelength is shorter than the emission wavelength, two-photon excitation requires simultaneous excitation by two photons with longer wavelength than the emitted light. Two-photon excitation microscopy typically uses near-infrared (NIR) excitation light which can also excite fluorescent dyes. However, for each excitation, two photons of NIR light are absorbed. Using infrared light minimizes scattering in the tissue. Due to the multiphoton absorption, the background signal is strongly suppressed. Both effects lead to an increased penetration depth for this technique. Two-photon excitation can be a superior alternative to confocal microscopy due to its deeper tissue penetration, efficient light d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LMS Class 2P 4-4-0
The London Midland and Scottish Railway Class 2P 4-4-0 was a class of steam locomotive designed for light passenger work. Overview The class was introduced in 1928 and was a post-grouping development of the Midland Railway 483 Class with modified dimensions and reduced boiler mountings. The numbering continued from where the Midland engines left off at 563 and eventually reached 700. 138 were built, though numbering is slightly complicated by renumberings and transfers. Details Numbers 633 and 653 were fitted with Dabeg feedwater heater in 1933. Numbers 591 and 639 were withdrawn in 1934 after being heavily damaged in an accident at Port Eglinton Junction near Cumberland Street Station, Glasgow on 6 September of the same year. After nationalisation in 1948, British Railways added 40000 to the numbers of the remaining 136 engines. Further withdrawals came between 1954 and 1962. All were scrapped. Models Hornby produce a 00 gauge model based on the old Dapol ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2P Reserves
Proven reserves (also called measured reserves, 1P, and reserves) is a measure of fossil fuel energy reserves, such as oil reserves, natural gas reserves, and coal reserves. It is defined as the " antity of energy sources estimated with reasonable certainty, from the analysis of geologic and engineering data, to be recoverable from well established or known reservoirs with the existing equipment and under the existing operating conditions." A reserve is considered proven if it is probable that at least 90% of the resource is recoverable by economically profitable means. Operating conditions are taken into account when determining if a reserve is classified as proven. Operating conditions include operational break-even price, regulatory and contractual approvals, without which the reserve cannot be classified as proven. Price changes therefore can have a large impact on the classification of proven reserves. Regulatory and contractual conditions may change, and also affect the am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2 Pistols
Jeremy Lemont Saunders (born June 11, 1983), better known by his stage name 2 Pistols (censored as 2P), is an American rapper from Tarpon Springs, Florida. After the local success of his independent single "Dirty Foot", he was offered a record deal with Universal Republic Records in 2007. His debut single, "She Got It" featuring T-Pain, was released in 2007 and peaked at number 7 on the Rhythmic Top 40 chart in 2008 and hit number 2 on the ''Billboard'' Hot Rap Tracks chart. Biography From a broken home, Saunders grew up being looked after by his extended family. By his teens, he became involved in local crime and in 2005 was incarcerated for eight months. After this, he became involved in music promotion and formed a group called Blood Money Union, which consisted of other DJs, producers and rappers. Saunders' first success in rapping came with a self-released record called "Dirty Foot", which he wrote while still in high school and distributed in the Tarpon Springs area at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two-photon Absorption
Two-photon absorption (TPA or 2PA) or two-photon excitation or non-linear absorption is the simultaneous absorption of two photons of identical or different frequencies in order to excite a molecule from one state (usually the ground state) to a higher energy, most commonly an excited electronic state. Absorption of two photons with different frequencies is called non-degenerate two-photon absorption. Since TPA depends on the simultaneous absorption of two photons, the probability of TPA is proportional to the square of the light intensity, thus it is a nonlinear optical process. The energy difference between the involved lower and upper states of the molecule is equal or smaller than the sum of the photon energies of the two photons absorbed. Two-photon absorption is a third-order process, with absorption cross section typically several orders of magnitude smaller than one-photon absorption cross section. Two-photon excitation of a fluorophore (a fluorescent molecule) leads to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Orbital
In atomic theory and quantum mechanics, an atomic orbital is a function describing the location and wave-like behavior of an electron in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atom's nucleus. The term ''atomic orbital'' may also refer to the physical region or space where the electron can be calculated to be present, as predicted by the particular mathematical form of the orbital. Each orbital in an atom is characterized by a set of values of the three quantum numbers , , and , which respectively correspond to the electron's energy, angular momentum, and an angular momentum vector component (magnetic quantum number). Alternative to the magnetic quantum number, the orbitals are often labeled by the associated harmonic polynomials (e.g., ''xy'', ). Each such orbital can be occupied by a maximum of two electrons, each with its own projection of spin m_s. The simple names s orbital, p orb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Airphil Express
Air Philippines Corporation, operating as PAL Express and formerly branded as Air Philippines and Airphil Express, is a wholly owned subsidiary airline of Philippine Airlines which is under its ownership. It is PAL's regional brand, with services from its hubs in Manila, Clark, Cebu, and Davao. The airline has been re-branded a number of times, first as Air Philippines, then Airphil Express, and is now known as PAL Express. After a series of financial losses, Air Philippines ceased operations until it was acquired by investors from Philippine Airlines. After the acquisition, the airline was re-launched as PAL Express, operating some routes and slot assignments of its sister company Philippine Airlines until its management decided to re-brand the carrier as a budget airline known as Airphil Express. However, in March 2013, the airline name was reverted to PAL Express. As a codeshare partner of Philippine Airlines, PAL Express operates as a full service carrier within a low-cost ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Artillery By Country
This list of artillery by country contains all artillery systems organized primarily by their country of origin. In cases where multiple countries collaborated on a project, a system could be listed under each of the major participants. Also, in outstanding cases where a system was adopted fully by another country, the system may be listed there as well. This list is not an attempt to list every artillery system ever used by each country. : ''For other categorized lists, see list of artillery by name and list of artillery by type.'' : ''Jump to a specific country in the table below:.'' __NOTOC__ Argentina ; Field artillery * Model 1968 105 mm model 1968 recoilless gun * CITEFA Model 77 Cold War/modern 155 mm gun/howitzer, based on the French 155mm gun mounted on AMX Mk F3 SP gun * CALA 30 155 mm L45 long range gun ; Self-propelled field artillery * VCA 155 self-propelled 155 mm howitzer, based on a TAM chassis with a Palmaria turret ; Rocket art ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome 2 (human)
Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 million base pairs and representing almost eight percent of the total DNA in human cells. Chromosome 2 contains the HOXD homeobox gene cluster. Chromosomes Humans have only twenty-three pairs of chromosomes, while all other extant members of Hominidae have twenty-four pairs. It is believed that Neanderthals and Denisovans had twenty-three pairs. Human chromosome 2 is a result of an end-to-end fusion of two ancestral chromosomes.It has been hypothesized that Human Chromosome 2 is a fusion of two ancestral chromosomes by Alec MacAndrew; accessed 18 May 2006. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Two Pence (British Decimal Coin)
The British decimal two pence coin (often shortened to 2p in writing and speech) is a denomination of sterling coinage equalling 2/100ths of a pound. Since the coin's introduction on 15 February 1971, the year British currency was decimalised, its obverse has featured four profiles of Queen Elizabeth II. In 2008 the design on its reverse changed from the original depiction of a plume ostrich feathers with a coronet to a segment of the Royal Shield. The two pence coin was originally minted from bronze, but changed in 1992 to copper-plated steel. As of March 2014 there were an estimated 6.55 billion 2p coins in circulation corresponding to a value of £131 million. 2p coins are legal tender for amounts only up to the sum of 20p when offered in repayment of a debt; however, the coin's legal tender status is not normally relevant for everyday transactions. Composition From its first minting in 1971 until 1992, two pence coins were made from bronze. In 1992, this was changed t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
