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Spirangle
In geometry, a spirangle is a spiral polygonal chain. Spirangles are similar to spirals in that they expand from a center point as they grow larger, but they are made out of straight line segments, instead of curves. Spirangle vectographs are used in vision therapy to promote stereopsis and help resolve problems with hand–eye coordination. Two-dimensional spirangles A two-dimensional spirangle is an open figure consisting of a line bent into angles similar to a corresponding polygon. The spirangle can start at a center point, or a distance from the center, and has some number of turns around the center point. Three-dimensional spirangles Three-dimensional spirangles have layers that slant upward, progressively gaining height from the previous segment. This is similar to staircases in large buildings that turn at the top of each flight. The segments also may progressively lose an amount of length and resemble a pyramid. Uses * Ophthalmology — * Electronics � ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vectograph
A vectograph is a type of stereoscopic print or transparency viewed by using the polarized 3D glasses most commonly associated with projected 3D motion pictures. Credit for the concept of the vectograph is due to Joseph Mahler, cousin of composer and conductor Gustav Mahler. He immigrated to the US from Czechoslovakia in 1938 and was hired by the Polaroid Corporation, where he worked with its founder Edwin Land, to develop his idea into a practical process. An elementary vectograph is a polarizing filter sheet that encodes a photographic image as areas that polarize light more or less strongly, corresponding to the darker and lighter areas of the image. When the sheet is viewed by itself in ordinary light, a pale image becomes visible. When viewed through a uniformly polarizing filter sheet oriented in the same plane of polarization, the image is almost completely invisible. If either sheet is rotated 90 degrees about its axis, so that their planes of polarization are at right a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductor
An inductor, also called a coil, choke, or reactor, is a Passivity (engineering), passive two-terminal electronic component, electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typically consists of an insulated wire wound into a Electromagnetic coil, coil. When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (''emf'') (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current through them. An inductor is characterized by its inductance, which is the ratio of the voltage to the rate of change of current. In the International System of Units (SI), the unit of inductance is the Henry (unit), henry (H) named for 19th century American scientist Joseph Henry. In the measurement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Springer Science & Business Media
Springer Science+Business Media, commonly known as Springer, is a German multinational publishing company of books, e-books and peer-reviewed journals in science, humanities, technical and medical (STM) publishing. Originally founded in 1842 in Berlin, it expanded internationally in the 1960s, and through mergers in the 1990s and a sale to venture capitalists it fused with Wolters Kluwer and eventually became part of Springer Nature in 2015. Springer has major offices in Berlin, Heidelberg, Dordrecht, and New York City. History Julius Springer founded Springer-Verlag in Berlin in 1842 and his son Ferdinand Springer grew it from a small firm of 4 employees into Germany's then second-largest academic publisher with 65 staff in 1872.Chronology ". Springer Science+Business Media. In 1964, Springer expanded its business internationally, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wolters Kluwer
Wolters Kluwer N.V. is a Dutch information services company. The company serves legal, business, tax, accounting, finance, audit, risk, compliance, and healthcare markets. Wolters Kluwer in its current form was founded in 1987 with a merger between Kluwer Publishers and Wolters Samsom. It operates in over 150 countries. The company is headquartered in Alphen aan den Rijn, Netherlands (Global). History Early history Jan-Berend Wolters founded the Schoolbook publishing house in Groningen, Netherlands, in 1836. In 1858, the Noordhoff publishing house was founded alongside the Schoolbook publishing house. The two publishing houses merged in 1968. Wolters-Noordhoff merged with Information and Communications Union (ICU) in 1972 and took the name ICU. ICU acquired Croner in 1977, ICU changed its name to Wolters-Samsom in 1983. The company began serving foreign law firms and multinational companies in China in 1985. In 1987, Elsevier, the largest publishing house in the Netherlands, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turtle Graphics
In computer graphics, turtle graphics are vector graphics using a relative cursor (the "turtle") upon a Cartesian plane (x and y axis). Turtle graphics is a key feature of the Logo programming language. It is also a simple and didactic way of dealing with moving frames. Overview The turtle has three attributes: a location, an orientation (or direction), and a pen. The pen, too, has attributes: color, width, and on/off state (also called ''down'' and ''up''). The turtle moves with commands that are relative to its own position, such as "move forward 10 spaces" and "turn left 90 degrees". The pen carried by the turtle can also be controlled, by enabling it, setting its color, or setting its width. A student could understand (and predict and reason about) the turtle's motion by imagining what they would do if they were the turtle. Seymour Papert called this "body syntonic" reasoning. A full turtle graphics system requires control flow, procedures, and recursion: many turtl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celestial Sphere
In astronomy and navigation, the celestial sphere is an abstract sphere that has an arbitrarily large radius and is concentric to Earth. All objects in the sky can be conceived as being projected upon the inner surface of the celestial sphere, which may be centered on Earth or the observer. If centered on the observer, half of the sphere would resemble a hemispherical screen over the observing location. The celestial sphere is a conceptual tool used in spherical astronomy to specify the position of an object in the sky without consideration of its linear distance from the observer. The celestial equator divides the celestial sphere into northern and southern hemispheres. Description Because astronomical objects are at such remote distances, casual observation of the sky offers no information on their actual distances. All celestial objects seem equally far away, as if fixed onto the inside of a sphere with a large but unknown radius, which appears to rotate westwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Search Algorithm
In computer science, a search algorithm is an algorithm designed to solve a search problem. Search algorithms work to retrieve information stored within particular data structure, or calculated in the Feasible region, search space of a problem domain, with Continuous or discrete variable, either discrete or continuous values. Although Search engine (computing), search engines use search algorithms, they belong to the study of information retrieval, not algorithmics. The appropriate search algorithm to use often depends on the data structure being searched, and may also include prior knowledge about the data. Search algorithms can be made faster or more efficient by specially constructed database structures, such as search trees, hash maps, and database indexes. Search algorithms can be classified based on their mechanism of searching into three types of algorithms: linear, binary, and hashing. Linear search algorithms check every record for the one associated with a target key i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jewelry
Jewellery (or jewelry in American English) consists of decorative items worn for personal adornment such as brooches, ring (jewellery), rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the clothes. From a western perspective, the term is restricted to durable Ornament (art), ornaments, excluding flowers for example. For many centuries metal such as gold often combined with gemstones, has been the normal material for jewellery, but other materials such as glass, shells and other plant materials may be used. Jewellery is one of the oldest types of archaeological artefact – with 100,000-year-old beads made from ''Nassarius'' shells thought to be the oldest known jewellery. The basic forms of jewellery vary between cultures but are often extremely long-lived; in European cultures the most common forms of jewellery listed above have persisted since ancient times, while other forms such as adornments for the nose or ankle, impo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
