The metre or meter is the base unit of length in the International System of Units. The SI unit symbol is m; the metre is defined as the length of the path travelled by light in vacuum in 1/299 792 458 of a second. The metre was defined in 1793 as one ten-millionth of the distance from the equator to the North Pole – as a result the Earth's circumference is 40,000 km today. In 1799, it was redefined in terms of a prototype metre bar. In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. In 1983, the current definition was adopted; the imperial inch is defined as 0.0254 metres. One metre is about 3 3⁄8 inches longer than a yard, i.e. about 39 3⁄8 inches. Metre is the standard spelling of the metric unit for length in nearly all English-speaking nations except the United States and the Philippines, which use meter. Other Germanic languages, such as German and the Scandinavian languages spell the word meter. Measuring devices are spelled "-meter" in all variants of English.
The suffix "-meter" has the same Greek origin as the unit of length. The etymological roots of metre can be traced to the Greek verb μετρέω and noun μέτρον, which were used for physical measurement, for poetic metre and by extension for moderation or avoiding extremism; this range of uses is found in Latin, French and other languages. The motto ΜΕΤΡΩ ΧΡΩ in the seal of the International Bureau of Weights and Measures, a saying of the Greek statesman and philosopher Pittacus of Mytilene and may be translated as "Use measure!", thus calls for both measurement and moderation. In 1668 the English cleric and philosopher John Wilkins proposed in an essay a decimal-based unit of length, the universal measure or standard based on a pendulum with a two-second period; the use of the seconds pendulum to define length had been suggested to the Royal Society in 1660 by Christopher Wren. Christiaan Huygens had observed that length to be 39.26 English inches. No official action was taken regarding these suggestions.
In 1670 Gabriel Mouton, Bishop of Lyon suggested a universal length standard with decimal multiples and divisions, to be based on a one-minute angle of the Earth's meridian arc or on a pendulum with a two-second period. In 1675, the Italian scientist Tito Livio Burattini, in his work Misura Universale, used the phrase metro cattolico, derived from the Greek μέτρον καθολικόν, to denote the standard unit of length derived from a pendulum; as a result of the French Revolution, the French Academy of Sciences charged a commission with determining a single scale for all measures. On 7 October 1790 that commission advised the adoption of a decimal system, on 19 March 1791 advised the adoption of the term mètre, a basic unit of length, which they defined as equal to one ten-millionth of the distance between the North Pole and the Equator. In 1793, the French National Convention adopted the proposal. In 1791, the French Academy of Sciences selected the meridional definition over the pendular definition because the force of gravity varies over the surface of the Earth, which affects the period of a pendulum.
To establish a universally accepted foundation for the definition of the metre, more accurate measurements of this meridian were needed. The French Academy of Sciences commissioned an expedition led by Jean Baptiste Joseph Delambre and Pierre Méchain, lasting from 1792 to 1799, which attempted to measure the distance between a belfry in Dunkerque and Montjuïc castle in Barcelona to estimate the length of the meridian arc through Dunkerque; this portion of the meridian, assumed to be the same length as the Paris meridian, was to serve as the basis for the length of the half meridian connecting the North Pole with the Equator. The problem with this approach is that the exact shape of the Earth is not a simple mathematical shape, such as a sphere or oblate spheroid, at the level of precision required for defining a standard of length; the irregular and particular shape of the Earth smoothed to sea level is represented by a mathematical model called a geoid, which means "Earth-shaped". Despite these issues, in 1793 France adopted this definition of the metre as its official unit of length based on provisional results from this expedition.
However, it was determined that the first prototype metre bar was short by about 200 micrometres because of miscalculation of the flattening of the Earth, making the prototype about 0.02% shorter than the original proposed definition of the metre. Regardless, this length became the French standard and was progressively adopted by other countries in Europe; the expedition was fictionalised in Le mètre du Monde. Ken Alder wrote factually about the expedition in The Measure of All Things: the seven year odyssey and hidden error that transformed the world. In 1867 at the second general conference of the International Association of Geodesy held in Berlin, the question of an international standard unit of length was discussed in order to combine the measurements made in different countries to determine the size and shape of the Earth; the conference recommended the adoption of the metre and the creation of an internatio
Geometry is a branch of mathematics concerned with questions of shape, relative position of figures, the properties of space. A mathematician who works in the field of geometry is called a geometer. Geometry arose independently in a number of early cultures as a practical way for dealing with lengths and volumes. Geometry began to see elements of formal mathematical science emerging in the West as early as the 6th century BC. By the 3rd century BC, geometry was put into an axiomatic form by Euclid, whose treatment, Euclid's Elements, set a standard for many centuries to follow. Geometry arose independently in India, with texts providing rules for geometric constructions appearing as early as the 3rd century BC. Islamic scientists expanded on them during the Middle Ages. By the early 17th century, geometry had been put on a solid analytic footing by mathematicians such as René Descartes and Pierre de Fermat. Since and into modern times, geometry has expanded into non-Euclidean geometry and manifolds, describing spaces that lie beyond the normal range of human experience.
While geometry has evolved throughout the years, there are some general concepts that are more or less fundamental to geometry. These include the concepts of points, planes, surfaces and curves, as well as the more advanced notions of manifolds and topology or metric. Geometry has applications to many fields, including art, physics, as well as to other branches of mathematics. Contemporary geometry has many subfields: Euclidean geometry is geometry in its classical sense; the mandatory educational curriculum of the majority of nations includes the study of points, planes, triangles, similarity, solid figures and analytic geometry. Euclidean geometry has applications in computer science and various branches of modern mathematics. Differential geometry uses techniques of linear algebra to study problems in geometry, it has applications in physics, including in general relativity. Topology is the field concerned with the properties of geometric objects that are unchanged by continuous mappings. In practice, this means dealing with large-scale properties of spaces, such as connectedness and compactness.
Convex geometry investigates convex shapes in the Euclidean space and its more abstract analogues using techniques of real analysis. It has close connections to convex analysis and functional analysis and important applications in number theory. Algebraic geometry studies geometry through the use of multivariate polynomials and other algebraic techniques, it has applications including cryptography and string theory. Discrete geometry is concerned with questions of relative position of simple geometric objects, such as points and circles, it shares many principles with combinatorics. Computational geometry deals with algorithms and their implementations for manipulating geometrical objects. Although being a young area of geometry, it has many applications in computer vision, image processing, computer-aided design, medical imaging, etc; the earliest recorded beginnings of geometry can be traced to ancient Mesopotamia and Egypt in the 2nd millennium BC. Early geometry was a collection of empirically discovered principles concerning lengths, angles and volumes, which were developed to meet some practical need in surveying, construction and various crafts.
The earliest known texts on geometry are the Egyptian Rhind Papyrus and Moscow Papyrus, the Babylonian clay tablets such as Plimpton 322. For example, the Moscow Papyrus gives a formula for calculating the volume of a truncated pyramid, or frustum. Clay tablets demonstrate that Babylonian astronomers implemented trapezoid procedures for computing Jupiter's position and motion within time-velocity space; these geometric procedures anticipated the Oxford Calculators, including the mean speed theorem, by 14 centuries. South of Egypt the ancient Nubians established a system of geometry including early versions of sun clocks. In the 7th century BC, the Greek mathematician Thales of Miletus used geometry to solve problems such as calculating the height of pyramids and the distance of ships from the shore, he is credited with the first use of deductive reasoning applied to geometry, by deriving four corollaries to Thales' Theorem. Pythagoras established the Pythagorean School, credited with the first proof of the Pythagorean theorem, though the statement of the theorem has a long history.
Eudoxus developed the method of exhaustion, which allowed the calculation of areas and volumes of curvilinear figures, as well as a theory of ratios that avoided the problem of incommensurable magnitudes, which enabled subsequent geometers to make significant advances. Around 300 BC, geometry was revolutionized by Euclid, whose Elements considered the most successful and influential textbook of all time, introduced mathematical rigor through the axiomatic method and is the earliest example of the format still used in mathematics today, that of definition, axiom and proof. Although most of the contents of the Elements were known, Euclid arranged them into a single, coherent logical framework; the Elements was known to all educated people in the West until the middle of the 20th century and its contents are still taught in geometry classes today. Archimedes of Syracuse used the method of exhaustion to calculate the area under the arc of a parabola with the summation of an infinite series, gave remarkably accurate approximations of Pi.
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Philosophical Investigations is a work by the philosopher Ludwig Wittgenstein. It was first published posthumously in 1953. Wittgenstein discusses numerous problems and puzzles in the fields of semantics, philosophy of mathematics, philosophy of psychology, philosophy of action, philosophy of mind, putting forth the view that conceptual confusions surrounding language use are at the root of most philosophical problems. Wittgenstein alleges that the problems are traceable to a set of related assumptions about the nature of language, which themselves presuppose a particular conception of the essence of language; this conception is considered and rejected for being too general. This view can be seen to contradict or discard much of what he argued in his earlier work Tractatus Logico-Philosophicus. Philosophical Investigations is influential. Within the analytic tradition, the book is considered by many as being one of the most important philosophical works of the 20th century, it continues to influence contemporary philosophers those studying mind and language.
Wittgenstein begins the book with a quotation from Augustine of Hippo, whom he cites as a proponent of the generalized and limited conception that he summarizes: The individual words in language name objects—sentences are combinations of such names. In this picture of language we find the roots of the following idea: Every word has a meaning; this meaning is correlated with the word. It is the object, he sets out throughout the rest of the book to demonstrate the limitations of this conception, including, he argues, with many traditional philosophical puzzles and confusions that arise as a result of this limited picture. Philosophical Investigations was not ready for publication when Wittgenstein died in 1951. G. E. M. Anscombe translated Wittgenstein's manuscript into English, it was first published in 1953. There are multiple editions of Philosophical Investigations with the popular third edition and 50th anniversary edition having been edited by Anscombe: First Edition: Macmillan Publishing Company, 1953.
Second Edition: Blackwell Publishers, 1958. Third Edition: Prentice Hall, 1973. 50th Anniversary Edition: Blackwell Publishers, 2001. This edition includes the original German text in addition to the English translation. Fourth Edition: Wiley-Blackwell, 2009; the text is divided into two parts, consisting of what Wittgenstein calls, in the preface, translated by Anscombe as "remarks". In the first part, these remarks are more than a paragraph long and are numbered sequentially. In the second part, the remarks numbered using Roman numerals. In the index, remarks from the first part are referenced by their number rather than page; the comparatively unusual nature of the second part is due to the fact that it comprises notes that Wittgenstein may have intended to re-incorporate into the first part. Subsequent to his death it was published as a "Part II" in the first and third editions. However, in light of continuing uncertainty about Wittgenstein's intentions regarding this material, the fourth edition re-titles "Part I" as "Philosophical Investigations" proper, "Part II" as "Philosophy of Psychology – A Fragment."
In standard references, a small letter following a page, section, or proposition number indicates a paragraph. Philosophical Investigations is unique in its approach to philosophy. A typical philosophical text presents a philosophical problem and critiques various alternative approaches to solving it, presents its approach, argues in favour of that approach. In contrast, Wittgenstein's book treats philosophy as an activity, rather along the lines of Socrates's famous method of maieutics. Rather than presenting a philosophical problem and its solution, Wittgenstein engages in a dialogue, where he provides a language-game, that describes how one might be inclined to think about it, shows why that inclination suffers from conceptual confusion; the following is an excerpt from the first entry in the book that exemplifies this method:...think of the following use of language: I send someone shopping. I give him a slip marked'five red apples', he takes the slip to the shopkeeper, who opens the drawer marked'apples' he looks up the word'red' in a table and finds a colour sample opposite it.
Well, I assume. Explanations come to an end somewhere.—But what is the meaning of the word'five'? No such thing was in question here; this example is typical of the book's style. We can see each of the steps in Wittgenstein's method: The reader is presented with a use of language: someone is sent shopping with an order on a slip. Wittgenstein supplies the response of one or more imagined interlocutors, he may put these statements in quotes to distinguish them from his own: "But how does he know where and how he is to look up the word'red' and what he is to do with the
A French curve is a template made from metal, wood or plastic composed of many different curves. It is used in fashion design to draw smooth curves of varying radii; the shapes are segments of the Euler clothoid curve. The curve is placed on the drawing material, a pencil, knife or other implement is traced around its curves to produce the desired result. French curve physical templates are used for original high fashion design and by home sewists most usefully in necklines, sleeve and waist variations; the varied curve radii allow for smooth and stylish personalized adjustments of standard purchased clothing patterns for an excellent, personalized fit. Fashion designers and sewists may use a selection of french curves, hip curves, straight edges and L-shaped right angle rulers, they may be with measurements marked in metric or imperial. As modern computer-aided design systems use vector-based graphics to achieve a precise radius, mechanical templates have become obsolete outside of sewists' home pattern adjustments and fashion designs.
Digital computers can be used to generate a set of coordinates that describe an arbitrary curve, the points can be connected with line segments to approximate the curve with a high degree of accuracy. Some computer-graphics systems make use of Bézier curves, which allow a curve to be bent in real time on a display screen to follow a set of coordinates, much in the way a French curve would be placed on a set of three or four points on paper. Flat spline – A long flexible batten used to produce a fair curve through a set of points Lesbian rule – A flexible strip of lead that could be bent to the curves of a molding, used to measure or reproduce irregular curves Ruler – An instrument used to measure distances or to rule straight lines Technical drawing tool – Tools and instruments used for accurate and precise manual draughting Weisstein, Eric W. French Curve from MathWorld. Use of the French Curve from Integrated Publishing
Plastic is material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and so can be molded into solid objects. Plasticity is the general property of all materials which can deform irreversibly without breaking but, in the class of moldable polymers, this occurs to such a degree that their actual name derives from this specific ability. Plastics are organic polymers of high molecular mass and contain other substances, they are synthetic, most derived from petrochemicals, however, an array of variants are made from renewable materials such as polylactic acid from corn or cellulosics from cotton linters. Due to their low cost, ease of manufacture and imperviousness to water, plastics are used in a multitude of products of different scale, including paper clips and spacecraft, they have prevailed over traditional materials, such as wood, stone and bone, metal and ceramic, in some products left to natural materials. In developed economies, about a third of plastic is used in packaging and the same in buildings in applications such as piping, plumbing or vinyl siding.
Other uses include automobiles and toys. In the developing world, the applications of plastic may differ—42% of India's consumption is used in packaging. Plastics have many uses in the medical field as well, with the introduction of polymer implants and other medical devices derived at least from plastic; the field of plastic surgery is not named for use of plastic materials, but rather the meaning of the word plasticity, with regard to the reshaping of flesh. The world's first synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term'plastics'. Many chemists have contributed to the materials science of plastics, including Nobel laureate Hermann Staudinger, called "the father of polymer chemistry" and Herman Mark, known as "the father of polymer physics"; the success and dominance of plastics starting in the early 20th century led to environmental concerns regarding its slow decomposition rate after being discarded as trash due to its composition of large molecules.
Toward the end of the century, one approach to this problem was met with wide efforts toward recycling. The word plastic derives from the Greek πλαστικός meaning "capable of being shaped or molded" and, in turn, from πλαστός meaning "molded"; the plasticity, or malleability, of the material during manufacture allows it to be cast, pressed, or extruded into a variety of shapes, such as: films, plates, bottles, amongst many others. The common noun plastic should not be confused with the technical adjective plastic; the adjective is applicable to any material which undergoes a plastic deformation, or permanent change of shape, when strained beyond a certain point. For example, aluminum, stamped or forged exhibits plasticity in this sense, but is not plastic in the common sense. By contrast, some plastics will, in their finished forms, break before deforming and therefore are not plastic in the technical sense. Most plastics contain organic polymers; the vast majority of these polymers are formed from chains of carbon atoms,'pure' or with the addition of: oxygen, nitrogen, or sulfur.
The chains comprise many repeat units, formed from monomers. Each polymer chain will have several thousand repeating units; the backbone is the part of the chain, on the "main path", linking together a large number of repeat units. To customize the properties of a plastic, different molecular groups "hang" from this backbone; these pendant units are "hung" on the monomers, before the monomers themselves are linked together to form the polymer chain. It is the structure of these side chains; the molecular structure of the repeating unit can be fine tuned to influence specific properties in the polymer. Plastics are classified by: the chemical structure of the polymer's backbone and side chains. Plastics can be classified by: the chemical process used in their synthesis, such as: condensation and cross-linking. Plastics can be classified by: their various physical properties, such as: hardness, tensile strength, resistance to heat and glass transition temperature, by their chemical properties, such as the organic chemistry of the polymer and its resistance and reaction to various chemical products and processes, such as: organic solvents and ionizing radiation.
In particular, most plastics will melt upon heating to a few hundred degrees celsius. Other classifications are based on qualities that are relevant for product design. Examples of such qualities and classes are: thermoplastics and thermosets, conductive polymers, biodegradable plastics and engineering plastics and other plastics with particular structures, such as elastomers. One important classification of plastics is by the permanence or impermanence of their form, or whether they are: thermoplastics or thermosetting polymers. Thermoplastics are the plastics that, when heated, do not undergo chemical change in their composition and so can be molded again and again. Examples include: polyethylene, polypropylene and polyvinyl chloride. Common thermoplastics range from 20,000 to 500,000 amu, while thermosets are assumed to have infinite molecular weight. Thermosets, or thermosetting polymers, can melt and take shape only once: after they have solidified, they stay solid. In the thermosetting process, a chemical reaction occurs, irreversible.
Ivory is a hard, white material from the tusks and teeth of animals, that consists of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mammals is the same, regardless of the species of origin; the trade in certain teeth and tusks other than elephant is widespread. It has been valued since ancient times in art or manufacturing for making a range of items from ivory carvings to false teeth, fans and joint tubes. Elephant ivory is the most important source, but ivory from mammoth, hippopotamus, sperm whale, killer whale and wart hog are used as well. Elk have two ivory teeth, which are believed to be the remnants of tusks from their ancestors; the national and international trade in ivory of threatened species such as African and Asian elephants is illegal. The word ivory derives from the ancient Egyptian âb, âbu, through the Latin ebor- or ebur. Both the Greek and Roman civilizations practiced ivory carving to make large quantities of high value works of art, precious religious objects, decorative boxes for costly objects.
Ivory was used to form the white of the eyes of statues. There is some evidence of either walrus ivory used by the ancient Irish. Solinus, a Roman writer in the 3rd century claimed that the Celtic peoples in Ireland would decorate their sword-hilts with the'teeth of beasts that swim in the sea'. Adomnan of Iona wrote a story about St Columba giving a sword decorated with carved ivory as a gift that a penitent would bring to his master so he could redeem himself from slavery; the Syrian and North African elephant populations were reduced to extinction due to the demand for ivory in the Classical world. The Chinese have long valued ivory for utilitarian objects. Early reference to the Chinese export of ivory is recorded after the Chinese explorer Zhang Qian ventured to the west to form alliances to enable the eventual free movement of Chinese goods to the west. Southeast Asian kingdoms included tusks of the Indian elephant in their annual tribute caravans to China. Chinese craftsmen carved ivory to make everything from images of deities to the pipe stems and end pieces of opium pipes.
The Buddhist cultures of Southeast Asia, including Myanmar, Thailand and Cambodia, traditionally harvested ivory from their domesticated elephants. Ivory was prized for containers due to its ability to keep an airtight seal, it was commonly carved into elaborate seals utilized by officials to "sign" documents and decrees by stamping them with their unique official seal. In Southeast Asian countries, where Muslim Malay peoples live, such as Malaysia and the Philippines, ivory was the material of choice for making the handles of kris daggers. In the Philippines, ivory was used to craft the faces and hands of Catholic icons and images of saints prevalent in the Santero culture. Tooth and tusk ivory can be carved into a vast variety of objects. Examples of modern carved ivory objects are okimono, jewelry, flatware handles, furniture inlays, piano keys. Additionally, warthog tusks, teeth from sperm whales and hippos can be scrimshawed or superficially carved, thus retaining their morphologically recognizable shapes.
Ivory usage in the last thirty years has moved towards mass production of souvenirs and jewelry. In Japan, the increase in wealth sparked consumption of solid ivory hanko – name seals – which before this time had been made of wood; these hanko can be carved out in a matter of seconds using machinery and were responsible for massive African elephant decline in the 1980s, when the African elephant population went from 1.3 million to around 600,000 in ten years. Prior to the introduction of plastics, ivory had many ornamental and practical uses because of the white color it presents when processed, it was used to make cutlery handles, billiard balls, piano keys, Scottish bagpipes, buttons and a wide range of ornamental items. Synthetic substitutes for ivory in the use of most of these items have been developed since 1800: the billiard industry challenged inventors to come up with an alternative material that could be manufactured. Ivory can be taken from dead animals – however, most ivory came from elephants that were killed for their tusks.
For example, in 1930 to acquire 40 tons of ivory required the killing of 700 elephants. Other animals which are now endangered were preyed upon, for example, which have hard white ivory prized for making artificial teeth. In the first half of the 20th century, Kenyan elephant herds were devastated because of demand for ivory, to be used for piano keys. During the Art Deco era from 1912 to 1940, dozens of European artists used ivory in the production of chryselephantine statues. Two of the most frequent users of ivory in their sculptured artworks were Ferdinand Preiss and Claire Colinet. Owing to the rapid decline in the populations of the animals that produce it, the importation and sale of ivory in many countries is banned or restricted. In the ten years preceding a decision in 1989 by CITES to ban international trade in African elephant ivory, the population of African elephants declined from 1.3 million to around 600,000. It was found by investigators from the Environmental Investigation Agency that CITES sales of stockpiles from Singapore and
Hanzhong is a prefecture-level city in the southwest of Shaanxi province, bordering the provinces of Sichuan to the south and Gansu to the west. Hanzhong is located at the nowadays headwater of the Han River, the largest tributary of the Yangtze River; however some modern historians suggested that the nearby Xihan River, a major tributary of the neighbouring Jialing River to the west drained into the Han River instead, was rerouted by a large earthquake at the Wudu Commandery in 186 BC, possible due to landslide damming. This might explain the city's name, since its location was once the middle point of the ancient Han River; the founder of the Han dynasty, Liu Bang, was once enfeoffed as the king of the Hanzhong region after overthrowing the Qin dynasty. During the Chu-Han contention, Liu Bang shortened his title to the King of Han, used it as the name of his imperial dynasty. In this way, Hanzhong was responsible for the naming of the Han dynasty, hailed as the first golden age in Chinese history, as well as the principal ethnic group who proudly inherited the name from the dynasty's prominence.
Hanzhong city consists of one urban district named Hantai. There are ten surrounding rural counties: and one national economics and technology development zone. In 2013, the population was 3.84 million. The local dialect of Hanzhong is the Chengdu-Chongqing dialect of Southwestern Mandarin. There are few references to Hanzhong before the Qin dynasty's unification of China in 221 BC; the Book of Documents refers to an area called Liangzhou, while Sima Qian's book Records of the Grand Historian speaks of a "Bao state", both of which are believed to refer to the area now called Hanzhong. From 900 BC, the area has been called Nanzheng; the ancient geographical treatise entitled Shui Jing Zhu records that Duke Huan of Zheng, a vassal lord from the Western Zhou dynasty, was slain in a battle with the nomadic Quanrong people, some of the Zheng citizens fled the capital to establish a new settlement to the south, giving rise to the area's name. However, the veracity of this story is controversial. In the Qin dynasty the area was governed as the Hanzhong Commandery, whose seat was in current day Nanzheng County, south of the Hanzhong urban area.
In 207 BC, the Qin dynasty collapsed. Liu Bang, who would become the founding emperor of the Han dynasty, was made lord of Hanzhong, he spent several years there before raising an army to challenge his archrival, Xiang Yu, during the Chu–Han Contention. In 206 BC, after the victory at Gaixia, Liu Bang named his imperial dynasty after his native district, as was customary. However, he chose Hanzhong rather than his birthplace Pei County. Thus, Hanzhong gave its name to the Han dynasty. In the second century AD, the Eastern Han dynasty weakened. Outsiders from the Ba region attacked the Hanzhong area; the Han dynasty lost power. Zhang Lu, supported by followers of a Taoist sect, Way of the Celestial Masters, led an independent theocratic government in Hanzhong. Thirty years after the Battle of Yangping, Zhang Lu surrendered Zanghong to the warlord, Cao Cao. Prior to and during the Three Kingdoms period, Hanzhong was a militarily strategically important site, it is located at a critical point along the route an army would take from the Central Plain to the Sichuan Basin.
At this time, Cao Cao lost control of Hanzhong to Liu Bei, who assumed the title of King of Hanzhong. Ruins and landmarks of the Three Kingdoms era remaining in Hanzhong include the tomb of the Shu Han chancellor Zhuge Liang. Much of this period of Hanzhong's history is retold in the historical novel Romance of the Three Kingdoms. In Hanzhong, between the end of the Han dynasty and the beginning of the Tang dynasty there was political turmoil. In 784, when the capital, Chang'an was captured, the Emperor Dezong of Tang fled to Hanzhong. During the Northern Song dynasty, Hanzhong became economically wealthy with city tax revenue just behind that of regional capitals such as Kaifeng and Chengdu. In 1331, during the Ming dynasty in the reign of the Hongwu Emperor, extensive renovations were made to Hanzhong's infrastructure; this work brought Zanghong to its present form. The Wanli Emperor installed Zhu Changhao, as king of Hanzhong. Changhao built a luxurious palace in what is now the Children's Park.
The palace's Radiant Glass Wall was demolished during road construction in 1935. Since a 13.6 m section has been rebuilt on the eastern end of Sanpu Street. In 1643, Zhu Changhao fled south to Sichuan ahead of Li Zicheng's rebel army; as he departed, his Hanzhong palace was looted. Qing dynasty historians remembered the empty palace. In December 1949, in the Chinese Civil War, Hanzhong was captured by the People's Liberation Army as the Communist Party of China conquered the Kuomintang; the governance of Zanghong, including the municipal executive, the legislature and the judiciary are located in Hantai District. The offices of the Communist Party of China and the Public Security Bureau are located in Hantai District. In 2013, the Hanzhong regional gross domestic product was 88173 million yuan; the annual gross domestic product per capita was 25769 yuan. The 012 base was established in Hanzhong in the 19