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Polar Flagella
Polar may refer to: Geography Polar may refer to: * Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates *Polar climate, the climate common in polar regions * Polar regions of Earth, locations within the polar circles, referred to as the Arctic and Antarctic Places *Polar, Wisconsin, town in Langlade County, Wisconsin, United States **Polar (community), Wisconsin, unincorporated community in Langlade County, Wisconsin, United States People * Polar (musician), Norwegian electronic music producer Arts, entertainment and media Music Labels and studios * Polar Music, a record label * Polar Studios, music studio of ABBA in Sweden Albums * ''Polar'' (album), second album by the High Water Marks * ''Polars'' (album), an album by the Dutch metal band, Textures Other uses in arts, entertainment and media * ''Polar'' (webcomic), a webcomic and series of graphic novel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geographical Pole
A geographical pole or geographic pole is either of the two points on Earth where its axis of rotation intersects its surface. The North Pole lies in the Arctic Ocean while the South Pole is in Antarctica. North and South poles are also defined for other planets or satellites in the Solar System, with a North pole being on the same side of the invariable plane as Earth's North pole. Relative to Earth's surface, the geographic poles move by a few metres over periods of a few years. This is a combination of Chandler wobble, a free oscillation with a period of about 433 days; an annual motion responding to seasonal movements of air and water masses; and an irregular drift towards the 80th west meridian. As cartography requires exact and unchanging coordinates, the averaged locations of geographical poles are taken as fixed ''cartographic poles'' and become the points where the body's great circles of longitude intersect. See also * Earth's rotation * Polar motion * Poles of as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Grammatical Polarity
In linguistics and grammar, affirmation (abbreviated ) and negation () are ways in which grammar encodes positive and negative polarity into verb phrases, clauses, or other utterances. An affirmative (positive) form is used to express the validity or truth of a basic assertion, while a negative form expresses its falsity. For example, the affirmative sentence "Jane is here" asserts that it is true that Jane is currently located near the speaker. Conversely, the negative sentence "Jane is not here" asserts that it is not true that Jane is currently located near the speaker. The grammatical category associated with affirmatives and negatives is called polarity. This means that a clause, sentence, verb phrase, etc. may be said to have either affirmative or negative polarity (its polarity may be either affirmative or negative). Affirmative is typically the unmarked polarity, whereas a negative statement is marked in some way. Negative polarity can be indicated by negating words or pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Fleece
Polar fleece is a soft napped insulating fabric made from polyester. Uses Polar fleece is used in jackets, hats, sweaters, sweatpants, cloth diapers (nappies), gym clothes, hoodies, pajamas, blankets, and high-performance outdoor clothing. The produced fleece can be used to create clothes that are very light, soft, and easy to wash. Polar fleece can stretch more easily in one direction than in others. History Polar fleece originated in Massachusetts in 1979 when Malden Mills (now Polartec LLC), and Patagonia developed Synchilla (synthetic chinchilla). It was a new, light, strong pile fabric meant to mimic, and in some ways surpass, wool. Malden Mills CEO Aaron Feuerstein intentionally declined to patent polar fleece, allowing the material to be produced cheaply and widely by many vendors, leading to the material's quick and wide acceptance. Malden Mills registered PolarFleece as a trademark with the United States Patent and Trademark Office on October 6, 1981. Characteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Curve (aviation)
The drag curve or drag polar is the relationship between the drag on an aircraft and other variables, such as lift, the coefficient of lift, angle-of-attack or speed. It may be described by an equation or displayed as a graph (sometimes called a "polar plot"). Drag may be expressed as actual drag or the coefficient of drag. Drag curves are closely related to other curves which do not show drag, such as the power required/speed curve, or the sink rate/speed curve. The drag curve The significant aerodynamic properties of aircraft wings are summarised by two dimensionless quantities, the lift and drag coefficients and . Like other such aerodynamic quantities, they are functions only of the angle of attack , the Reynolds number and the Mach number . and can be plotted against , or can be plotted against each other. The lift and the drag forces, and , are scaled by the same factor to get and , so = . and are at right angles, with parallel to the free stream velocit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POLAR III
POLAR III is a pedestrian test dummy created by Honda. The dummy is used to study how pedestrians are injured or killed when hit by automobiles. POLAR III has instruments to measure the level of injury throughout the body. About 5,000 pedestrians are killed in traffic accidents each year in the United States. By studying test dummy results and designing cars in such a way as to protect pedestrians as much as possible in the event of a collision, the number of fatalities and injuries due to pedestrians being struck may be reduced. See also * Crash test dummy * Pedestrian safety through vehicle design References POLAR IIICross member* ''National Geographic ''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...'' Magazine, July 2005 Vehicle safety technologies Automotive safety Ped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Polarity
In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole moment, with a negatively charged end and a positively charged end. Polar molecules must contain one or more polar bonds due to a difference in electronegativity between the bonded atoms. Molecules containing polar bonds have no molecular polarity if the bond dipoles cancel each other out by symmetry. Polar molecules interact through dipole–dipole intermolecular forces and hydrogen bonds. Polarity underlies a number of physical properties including surface tension, solubility, and melting and boiling points. Polarity of bonds Not all atoms attract electrons with the same force. The amount of "pull" an atom exerts on its electrons is called its electronegativity. Atoms with high electronegativitiessuch as fluorine, oxygen, and nitrogenexert a greater pull on electrons than atoms with lower electronegativities such as alkali metals and alkaline ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar (satellite)
The Global Geospace Science (GGS) ''Polar'' satellite was a NASA science spacecraft designed to study the polar magnetosphere and aurorae. It was launched into orbit in February 1996, and continued operations until the program was terminated in April 2008. The spacecraft remains in orbit, though it is now inactive. ''Polar'' is the sister ship to GGS ''Wind''. Launch It was designed and manufactured by Lockheed Martin, and launched at 11:23:59.997 UTC on February 24, 1996, aboard a McDonnell Douglas Delta II 7925-10 rocket from launch pad 2W at Vandenberg Air Force Base in Lompoc, California, to study the polar magnetosphere. The spacecraft was placed into a highly elliptical orbit with apogee at 9 Earth radii and perigee at 1.8 Earth radii (geocentric), 86 degrees inclination, with a period of around 18 hours. The apogee was initially over the northern polar region, but has since been precessing south at about 16° per year. Operations Sensors on the spacecraft gathered mul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar (cataclysmic Variable)
In astronomy, a polar is a highly magnetic type of cataclysmic variable (CV) binary star system, originally known as an AM Herculis star after the prototype member AM Herculis. Like other CVs, polars contain two stars: an accreting white dwarf (WD), and a low-mass donor star (usually a red dwarf) which is transferring mass to the WD as a result of the WD's gravitational pull, overflowing its Roche lobe. Polars are distinguished from other CVs by the presence of a very strong magnetic field in the WD. Typical magnetic field strengths of polar systems are 10 million to 80 million gauss (1000–8000 teslas). The WD in the polar AN Ursae Majoris has the strongest known magnetic field among cataclysmic variables, with a field strength of 230 million gauss (23 kT). Accretion mechanism One of the most critical consequences of the WD's magnetism is that it synchronizes the rotational period of the WD with the orbital period of the binary; to first order, this means that the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Set
In functional and convex analysis, and related disciplines of mathematics, the polar set A^ is a special convex set associated to any subset A of a vector space X lying in the dual space X^. The bipolar of a subset is the polar of A^, but lies in X (not X^). Definitions There are at least three competing definitions of the polar of a set, originating in projective geometry and convex analysis. In each case, the definition describes a duality between certain subsets of a pairing of vector spaces \langle X, Y \rangle over the real or complex numbers (X and Y are often topological vector spaces (TVSs)). If X is a vector space over the field \mathbb then unless indicated otherwise, Y will usually, but not always, be some vector space of linear functionals on X and the dual pairing \left\langle \cdot, \cdot \right\rangle : X \times Y \to \mathbb will be the bilinear () defined by :\left\langle x, f \right\rangle := f(x). If X is a topological vector space then the space Y w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Curve
In algebraic geometry, the first polar, or simply polar of an algebraic plane curve ''C'' of degree ''n'' with respect to a point ''Q'' is an algebraic curve of degree ''n''−1 which contains every point of ''C'' whose tangent line passes through ''Q''. It is used to investigate the relationship between the curve and its dual, for example in the derivation of the Plücker formulas. Definition Let ''C'' be defined in homogeneous coordinates by ''f''(''x, y, z'') = 0 where ''f'' is a homogeneous polynomial of degree ''n'', and let the homogeneous coordinates of ''Q'' be (''a'', ''b'', ''c''). Define the operator :\Delta_Q = a+b+c. Then Δ''Q''''f'' is a homogeneous polynomial of degree ''n''−1 and Δ''Q''''f''(''x, y, z'') = 0 defines a curve of degree ''n''−1 called the ''first polar'' of ''C'' with respect of ''Q''. If ''P''=(''p'', ''q'', ''r'') is a non-singular point on the curve ''C'' then the equation of the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Coordinate System
In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a reference point and an angle from a reference direction. The reference point (analogous to the origin of a Cartesian coordinate system) is called the ''pole'', and the ray from the pole in the reference direction is the ''polar axis''. The distance from the pole is called the ''radial coordinate'', ''radial distance'' or simply ''radius'', and the angle is called the ''angular coordinate'', ''polar angle'', or ''azimuth''. Angles in polar notation are generally expressed in either degrees or radians (2 rad being equal to 360°). Grégoire de Saint-Vincent and Bonaventura Cavalieri independently introduced the concepts in the mid-17th century, though the actual term "polar coordinates" has been attributed to Gregorio Fontana in the 18th century. The initial motivation for the introduction of the polar system was the study of circula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Cone
Dual cone and polar cone are closely related concepts in convex analysis, a branch of mathematics. Dual cone In a vector space The dual cone ''C'' of a subset ''C'' in a linear space ''X'' over the reals, e.g. Euclidean space R''n'', with dual space ''X'' is the set :C^* = \left \, where \langle y, x \rangle is the duality pairing between ''X'' and ''X'', i.e. \langle y, x\rangle = y(x). ''C'' is always a convex cone, even if ''C'' is neither convex nor a cone. In a topological vector space If ''X'' is a topological vector space over the real or complex numbers, then the dual cone of a subset ''C'' ⊆ ''X'' is the following set of continuous linear functionals on ''X'': :C^ := \left\, which is the polar of the set -''C''. No matter what ''C'' is, C^ will be a convex cone. If ''C'' ⊆ then C^ = X^. In a Hilbert space (internal dual cone) Alternatively, many authors define the dual cone in the context of a real Hilbert space (such as R''n'' equipped with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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