Design.

In 1900, "Vizeadmiral" (Vice Admiral) Alfred von Tirpitz, the State Secretary for the "Reichsmarineamt" (Imperial Naval Office), secured the passage of the Second Naval Law, an amendment to the First Naval Law of 1898. The previous law had called for a total strength of nineteen battleships by 1 April 1904, which was reached with the five s, but the new law increased the projected battle fleet to a total of thirty-eight. The first tranche of vessels—the —introduced the gun, marking a significant increase in power over earlier German battleships. The naval command had originally intended to build ten battleships of the "Braunschweig" type, starting with the 1901 fiscal year with two ships built per year, but ultimately they only built five. During construction, a series of minor improvements were incorporated into subsequent designs, and by the time work began on the second vessel of the 1903 fiscal year, a more significantly altered design had been prepared.  A series of changes were made to the secondary and tertiary batteries for what became, the lead ship of the new class. The designers discarded the wing turrets that the "Braunschweig"s had used for some of their secondary guns; the turrets had required heavy support structures, which eliminating allowed the designers to place the secondary battery entirely in casemates in a more efficient arrangement. Removing the turrets also freed up deck space that could be used to add another pair of guns and placing the forward set of four in embrasures. "Deutschland" and her sister ship were designed for use as flagships for the fleet and a squadron, respectively, which required additional accommodation spaces. After "Deutschland", which had a mixed set of fire-tube and water-tube boilers, the remaining four members of the class received a uniform set of water-tube boilers. These were lighter, and the weight savings were passed on to the armor layout in the form of a slightly thicker armor belt and a strengthened upper deck.  The "Deutschland" design was criticized in Germany at the time the ships were being built, as the trend in all the major navies pointed to battleships armed with all-big-gun batteries; indeed, work on what would become the of dreadnought battleships had already begun in 1903. Tirpitz had insisted on building the "Deutschland"s in large part due to the fact that they were the largest design that could fit in Germany's existing naval infrastructure, most significantly the Kaiser Wilhelm Canal. Widening the canal and improving harbor facilities would be excessively expensive and Tirpitz sought to avoid another budgetary fight with the "Reichstag" so soon after the passage of the 1900 law.

General characteristics.

The "Deutschland"-class ships were long at the waterline and overall. They had a beam of and a draft of forward. The ships were designed to displace with a standard load, and displaced up to at full load. The "Deutschland"-class ships' hulls were built with transverse and longitudinal steel frames. Steel hull plates were riveted to the structure created by the frames. The hull was split into twelve watertight compartments, although "Pommern" had thirteen compartments. The hull included a double bottom that ran for 84 percent of the length of the ship.  Because "Deutschland" and "Hannover" were completed as flagships, they had an enlarged superstructure aft to house the larger command staffs they typically carried. "Deutschland" also had had a larger forward conning tower that incorporated a central fire-control position; "Pommern" received the same conning tower, but the other three ships had shorter towers without the fire-control room. All five members of the class were fitted with short military masts with lighter poles atop them that were fitted with spotting tops. The ships handled less easily than the preceding "Braunschweig"-class ships, though they suffered less marked weather helm. Their metacentric height was. Steering was controlled with a single rudder.  The ships' crews numbered 35 officers and 708 enlisted men. When one of them was a squadron flagship, the crew was augmented by 13 officers and 66 enlisted men; while serving as a second command ship, 2 officers and 23 enlisted men were added to her standard crew. After she became a training ship in 1935, "Schlesien"s crew consisted of 29 officers and 559 enlisted men, plus up to 214 cadets. "Schleswig-Holstein" differed somewhat; her crew as a training ship numbered 31 officers and 565 men and up to 175 cadets. "Deutschland" and her sisters carried a number of smaller vessels, including two picket boats, one admiral's barge, two launches, one pinnace, two cutters, two yawls, and two dinghies. The boats were handled with a pair of large cranes amidships; "Deutschland" had hers located further forward than the other members of the class.

Machinery.

"Deutschland" and her sisters were equipped with three-shaft triple-expansion steam engines that each drove a screw propeller; the outer screws were three-bladed and in diameter, while the center shaft used a four-bladed screw that was in diameter. Each engine was placed in its own engine room. "Deutschland" was fitted with eight water-tube boilers and six fire-tube boilers but the rest of the vessels received twelve water-tube boilers, all of which were coal-fired. These were divided into three boiler rooms, each of which was ducted into a funnel.  "Deutschland"s engines were rated at, while the other four ships' engines were rated at. The design speed for all of the ships was, though on trials all five ships exceeded both figures, with "Deutschland" reaching for and the other members of the class making for. "Schleswig-Holstein" was the fastest member of the class.  "Deutschland" was designed to carry of coal and the other members could carry, though additional spaces could be utilized as fuel storage, which increased fuel capacity to. This provided a maximum range of at a cruising speed of. Electrical power was supplied from four turbo-generators that supplied each at 110 volts.

Armament.

The ships carried the same main battery as the preceding "Braunschweig" class. The primary armament comprised four 28 cm SK L/40 quick-firing guns in hydraulically operated twin turrets. The turrets were placed on the centerline, one forward and one aft. The DrL C/01 turrets allowed the guns to depress to −4 degrees, and elevate to +30 degrees, which enabled a maximum range of. The guns fired shells at a muzzle velocity of. Ammunition storage amounted to 85 shells per gun.  The secondary battery consisted of fourteen 17 cm SK L/40 quick-firing guns, all of which were mounted in casemates. Five were placed on either side in the upper deck and the remaining four were located a deck above in the superstructure, one on each corner. The guns fired shells at a muzzle velocity of. These guns were chosen as they used the largest shell that could be reasonably handled without machinery. The guns could elevate to 22 degrees, which allowed a maximum range of. Their rate of fire was approximately one shot every nine to ten seconds, and each gun was supplied with 130 shells.  For defense against torpedo boats, the ships carried a tertiary battery of twenty-two 8.8 cm SK L/35 quick-firing guns. These were placed in casemates in hull sponsons, in embrasures in the superstructure, and in open mounts. The guns fired shells at a muzzle velocity of, and could be elevated to 25 degrees for a maximum range of. The ammunition allotment for each gun was 130 shells. The ships were temporarily fitted with four machine cannon, but these were quickly removed.  They were also armed with six torpedo tubes, with a total of 16 torpedoes. The tubes were all placed below the waterline, with one in the bow, one in the stern, and two on each broadside. These weapons were long and carried an TNT warhead. They could be set at two speeds for different ranges. At, the torpedoes had a range of. At an increased speed of, the range was reduced to.

Armor.

The "Deutschland"-class ships were equipped with Krupp cemented armor. "Deutschland" had a slightly different arrangement in the belt armor and the citadel in the superstructure. "Deutschland"s belt was at the waterline and tapered to on the lower edge. Her sister ships' belts was increased in thickness to at the waterline and down to on the bottom edge. In all five ships, this section of armor extended from the forward barbette to the aft one. On either end, the belt was reduced to. In all ships, the belt was backed by a layer of teak that was thick. Above the belt was a strake of armor that protected the casemate guns; in "Deutschland", this was thick, while on the other four ships the armor was 170 mm thick. All members of the class were fitted with cork cofferdams, a common practice at the time intended to prevent uncontrolled flooding in the event of shell hits.  All five ships had an armored deck that was thick. The deck sloped downward at the sides to connect with the lower edge of the belt, which provided a second layer to contain shell fragments from hits that penetrated the belt. The sloped section was in the bow and stern sections where the belt was thinner, and reduced to behind the main section of belt. Their forward conning towers were protected by on the sides and 80 mm on the roofs, while the rear conning towers had worth of armor on the sides. The main battery gun turrets had armored sides that were thick and roofs that were thick. The barbettes that held the turrets were armored with thick steel.

Modifications.

The ships of the "Deutschland" class were modified several times over their long careers. Modifications to the ships' masts were made between 1909 and 1914, shifting positions for searchlights and adding a fully enclosed spotting top to the fore mast. "Schlesien" and "Schleswig-Holstein" had eight oil-fired boilers installed in place of eight of their coal-fired boilers in late 1915. "Deutschland" had two of her 8.8 cm guns removed in late 1916 and a pair of 8.8 cm guns in anti-aircraft mountings were installed. Beginning in 1917, some of the ships began to be partially or fully disarmed so the guns could be used ashore during the war. "Deutschland" was completely disarmed in late 1917 and "Schleswig-Holstein" was reduced to just four SK L/45 guns and four 8.8 cm SK L/30 guns in 1918. "Schlesien" was similarly re-armed for training duties.  As the ships were returned to active service in the early 1920s, they received a series of modernizations and alterations to their armament. "Hannover", which had not been disarmed, carried her original battery of 28 cm and 17 cm guns, though her 88. cm battery had been reduced to eight weapons by the time she was recommissioned in 1921. All six of her torpedo tubes were removed at that time. "Schlesien" and "Schleswig-Holstein" were modernized in the mid-1920s, which included the re-installation of their 28 cm batteries, but in place of their 17 cm guns they each received fourteen SK L/45 guns, along with eight 8.8 cm guns as on "Hannover". They also had large tubular fore masts installed, which had large spotting tops. "Schlesien" had her two forward funnels trunked together, while "Schleswig-Holstein" had hers similarly modified in 1928. "Schlesien" had her forward sponsons plated over.  In 1930 and 1931, the ships were modified again. "Hannover" had a pair of above-water torpedo tubes and four of her 8.8 cm guns were replaced with four 8.8 cm anti-aircraft guns, and a tubular mast like her sisters was installed. She also had her bow sponsons plated over. "Schlesien" and "Schleswig-Holstein" each lost two of their 15 cm guns, received four of the 50 cm torpedo tubes, and exchanged all of their 8.8 guns for four 8.8 anti-aircraft guns. Both ships had another pair of 15 cm guns removed in 1935; "Schlesien" received four anti-aircraft guns at that time and "Schleswig-Holstein" received four the next year. Also in 1936, "Schleswig-Holstein" had her sponsons removed. As part of her conversion into a training ship, "Schlesien" had her remaining coal-burning boilers removed in 1938 and the boiler room became an accommodation space and training room for the cadets. The trunking from that boiler room was removed, leaving just two straight funnels.  After the start of World War II in September 1939, both ships underwent a series of changes to their armament, particularly to their anti-aircraft batteries. "Schleswig-Holstein" received an additional eight 2 cm guns that year. In February 1940, "Schlesien" received four L/83 anti-aircraft guns. In April, the ship had her remaining ten 15 cm guns removed, while "Schleswig-Holstein" only lost three of hers. In August, "Schlesien" had her 3.7 cm guns taken off and "Schleswig-Holstein" was almost completely disarmed, retaining only her 28 cm guns. The following year, she received four 8.8 cm guns, four 3.7 cm guns, and three 2 cm guns. By 1943, "Hannover" had been reconstructed for her planned role as a target ship, which involved removing most of her superstructure and all of her guns, though the turrets remained. "Schlesien" had the 3.7 cm guns returned that year, and in 1944, a pair of Bofors guns were added, along with sixteen more 2 cm guns, bringing the total to twenty barrels. Later that year, the 8.8 cm guns were replaced with six 10.5 cm anti-aircraft guns, her 4 cm battery was increased to seven or ten guns, and her 2 cm battery altered to either eighteen or twenty-two guns. "Schleswig-Holstein" was under refit to be similarly equipped, but work was not completed before her loss; she was slated to receive six of the 10.5 cm guns, ten 4 cm guns, and twenty-six of the 2 cm guns in addition to the four 3.7 cm weapons.

Service history.

After "Deutschland" entered service in 1906, she replaced the battleship as the fleet flagship, a role she held until 1913, when the new dreadnought took her place. With the commissioning of the rest of the class, the Home Fleet was reorganized as the High Seas Fleet in 1907. The vessels were assigned to I Battle Squadron and II Battle Squadron during this period, ultimately being concentrated in II Squadron along with three of the "Braunschweig"-class ships by the early 1910s as the "Nassau" and s filled the ranks of I Squadron. "Hannover" served as the flagship of I Squadron and later as the flagship of the deputy commander of II Squadron.  The ships' peacetime careers were fairly uneventful, consisting primarily of routine fleet training. Squadron and fleet exercises typically took place in April and May every year, a major fleet cruise generally followed in June and July, after which the fleet assembled for the annual large-scale maneuvers in late August and September. The major fleet cruises typically went to Norwegian waters in company with Kaiser Wilhelm II's yacht, though in 1908 and 1909, the fleet embarked on long-distance cruises out into the Atlantic, making visits to mainland Spain, the Canary Islands, and the Azores, Portugal. These came at the insistence of the fleet commander of the time, Prince Heinrich, who foresaw the need to operate at greater distances. During the summer cruise in July 1914, the fleet remained off Norway owing to the July Crisis that resulted in the start of World War I.

World War I.

Following the start of the war, the German fleet adopted a strategy of raids on the British coast to try to draw out portions of the British Grand Fleet where they could be defeated in detail. The battlecruisers of I Scouting Group conducted the raids while the battle squadrons of the High Seas Fleet stood by in support; these included the raid on Yarmouth in November 1914, the raid on Scarborough, Hartlepool and Whitby in December, and bombardment of Yarmouth and Lowestoft in April 1916. All five members of the class operated with the fleet during this period, though the anticipated battle failed to materialize during these operations. While not conducting fleet operations, the ships of II Squadron also patrolled the mouth of the river Elbe to support the light forces defending the German Bight; they also conducted training exercises in the relative safety of the Baltic Sea. In February 1915, "Deutschland" became the flagship of II Squadron.  In late May 1916, the Germans planned another operation to draw out the British fleet, which resulted in the Battle of Jutland on 31 May and 1 June. During the operation, the ships operated under the command of "Konteradmiral" (Rear Admiral) Franz Mauve. Being significantly slower than the rest of the German line of battle, the ships of II Squadron saw no action during the first stages of the battle. Toward the end of the fleet battle on the evening of 31 May, the five "Deutschland"-class ships came to the aid of the mauled battlecruisers of I Scouting Group, when Mauve places his ships between them and their counterparts in the British Battle Cruiser Fleet. In the growing darkness, the Germans had difficulty making out their targets and failed to score any hits; the British, however, managed to hit three of the "Deutschland"s. "Pommern" was forced briefly to haul out of line. Mauve then disengaged his ships, ending their only clash with British capital ships during the battle. As the German fleet withdrew overnight, II Squadron took up positions toward the rear of the German line. British light forces repeatedly clashed with the German fleet, and in one of these night actions, "Pommern" was hit by a torpedo from the destroyer, detonating one of her ammunition magazines and destroying the ship.  The German experience at Jutland demonstrated that pre-dreadnoughts had no place in a fleet action with dreadnoughts, and so the "Deutschland"s spent the rest of 1916 on coastal defense duty in the Elbe and occasionally in the Danish straits. In August 1917, II Battle Squadron was disbanded and most of the ships were reduced to secondary duties, being partially disarmed to free up guns for use ashore. "Deutschland" and "Schleswig-Holstein" became barracks ships and "Schlesien" served as a training ship. "Hannover" remained in active service for guard duty in the straits.

Inter-war years.

Following Germany's defeat in the war, the fleet was significantly reduced in size by the Treaty of Versailles, which permitted the Germans to retain six battleships of the "Braunschweig" and "Deutschland" classes, with another two in reserve. "Deutschland" was discarded in 1920 and was broken up by 1922, but the other three members of the class were kept by the postwar navy, which was reorganized as the "Reichsmarine" (Navy of the Realm). All three ships were heavily modernized in the early 1920s to prepare them for active service. "Hannover" was the first member of the class to return to service, in 1921, becoming the fleet flagship, a role she alternated with. "Schlesien" and "Schleswig-Holstein" remained out of service until the middle of the decade, when they were rearmed; "Schleswig-Holstein" became the flagship on her recommissioning in 1926. "Hannover" was modernized in the late 1920s after "Schlesien" recommissioned to take her place.  Throughout the 1920s, the ships took part in a training routine similar to that of the prewar years, including training exercises throughout the year and long-range training cruises that went as far as the Mediterranean Sea. The ships frequently went to Norwegian waters, as they had done under the Imperial government. "Hannover" was decommissioned in September 1931 and saw no further service, though there were plans to convert her into a target ship. "Schleswig-Holstein" and "Schlesien" remained on active duty into the early 1930s, but by 1933, the new armored ship had been commissioned, and so "Schlesien" was decommissioned to be converted into a dedicated training ship. "Schleswig-Holstein" followed for a similar rebuilding in 1935–1936. The two ships spent the rest of the decade training naval cadets, including a lengthy voyage to North and South America for "Schlesien" in 1936–1937. During this period, Germany came under the control of Adolf Hitler and the Nazi party, which set upon a rearmament and an aggressive foreign policy that led to the outbreak of World War II in September 1939.

World War II.

"Schleswig-Holstein" steamed to Danzig, Poland in late August 1939, and was moored off the Polish military depot at Westerplatte on the morning of 1 September. She opened fire on the base in Westerplatte, firing the first shots of World War II. The initial German attack was repulsed, leading to heavy fighting that "Schleswig-Holstein" supported for the next week, and culminating in the Polish surrender on 7 September. Later that month, "Schlesien" joined her sister in bombarding Polish positions along the coast, including the Hel Fortified Area. After the end of the Polish campaign, the ships returned to training duties, and in early 1940, "Schlesien" was used as an icebreaker in the Baltic Sea.  "Schleswig-Holstein" and "Schlesien" then participated in the occupation of Denmark and invasion of Norway, respectively, in April 1940. Afterward, "Schleswig-Holstein" was again removed from front-line service and used as a training ship, while "Schlesien" resumed her ice-breaking duties. In March 1941, "Schlesien" escorted mine-layers in the Baltic. After returning from this operation, she became a barracks ship in Gotenhafen.  "Hannover" was broken up starting in 1944; the work was completed by 1946.  In mid-1944, "Schlesien"s and "Schleswig-Holstein"s anti-aircraft armament was considerably strengthened to allow them to be used as air defense ships in the port of Gotenhafen. "Schleswig-Holstein" was attacked by RAF bombers in December 1944, and although she was sunk in shallow water, her weapons could still be used. After a fire permanently disabled the ship, her crew was sent ashore to assist in the defense of Marienburg. "Schlesien" provided fire support for German troops in the vicinity of Gotenhafen between 15 and 21 March 1945. In April, "Schlesien" was moved to Swinemünde to restock her ammunition supply as well as evacuate 1,000 wounded soldiers from the front. On 3 May she struck a mine outside Swinemünde; the following day she was scuttled by her crew in shallow water. Both ships were broken up in situ after the war.

The "Deutschland" class was a group of five pre-dreadnought battleships built for the German Kaiserliche Marine. The class comprised,,,, and. Built between 1903 and 1908, the ships closely resembled those of the preceding, though they had stronger armor protection. They were made obsolete before they were even completed by the launch of the revolutionary Royal Navy battleship in 1906. As a result, they were the last ships of that type built for the German Navy. They were followed by the s, Germany's first dreadnought battleships.

德国级战列舰或称德意志级战列舰()是德意志帝国海军所建造的五艘前无畏战列舰的船级。该船级由德国号、汉诺威号、波美拉尼亚号、西里西亚号和石勒苏益格-荷尔斯泰因号组成。这些舰只建于1903年至1907年间,它们与前级不伦瑞克级类似,但具有更强的装甲防护。然而这甚至在英国皇家海军的战列舰无畏号于1906年下水之前便已显得过时。因此,它们是德国海军建造的最后一级同类舰船。在其之后是拿骚级战列舰——即德国的首个无畏舰船级。


Progress.

The project was approved by the National Development and Reform Commission in April 2006, and projected to cost 23 billion Renminbi for the first two units. The cost will be shared between the China Power Investment Corporation, the China General Nuclear Power Group and two Liaoning companies. Liaoning Hongyanhe Nuclear Power Co., Ltd., a joint venture, is managing the construction and will be the operator of the plant once it goes online. The operator is a 45–45–10 joint venture of China Power Investment Corporation (now State Power Investment Corporation), China General Nuclear Power Group and Dalian Construction Investment Group.  Construction started in summer of 2006 with excavation of two large holes that will have the reactors put in them and a containment built around them. 'First concrete' for the first unit was poured in August 2007. 'Ground breaking' ceremony was held on 28 July 2010 for starting the work of two 1000 MWe CPR-1000 pressurized water reactors of phase II.  On 17 February 2013 Hongyanhe 1 was connected to the grid, having started criticality testing on 16 January 2013. It began commercial operation on 6 June.  On 23 November 2013 Hongyanhe 2 was connected to the grid.  Hongyanhe 4 achieved first criticality on 5 March 2016, was connected to the grid on 1 April 2016, and entered commercial operation on 20 September 2016.

Reactor data.

The Hongyanhe Nuclear Power Plant consist of 4 operational reactors, and 2 reactors under construction.

The Hongyanhe Nuclear Power Plant (红沿河核电站) is located in Donggang Town, Wafangdian in the Liaoning Province of China. The site is within the Prefecture-level city of Dalian, north of Dalian City proper. The first unit started commercial operations in June 2013.

红沿河核电站是位于中国辽宁省大连市瓦房店红沿河镇(原名东岗镇)的压水堆核电站,也是中国东北地区第一座核电站。红沿河核电站一期工程包含4台百万千瓦级核电机组,其总年发电量约为300亿千瓦时,超出大连市2012年全社会用电量287亿千瓦时的水平,约占辽宁省2012年全社会用电量的16%。辽宁红沿河核电站并网发电后,预计将优化辽宁地区电力供应结构,实现节能减排,改善空气和水质量:与同等规模的火力发电项目相比,红沿河核电站一期工程4台机组全部投入运行后,每年减少标准煤消耗约1000万吨,分别减少二氧化碳、二氧化硫、氮氧化物排放2400万吨、23万吨、15万吨,相当于植树造林6.6万公顷。


History.

Lazy evaluation was introduced for lambda calculus by Christopher Wadsworth and employed by the Plessey System 250 as a critical part of a Lambda-Calculus Meta-Machine, reducing the resolution overhead for access to objects in a capability-limited address space. For programming languages, it was independently introduced by Peter Henderson and James H. Morris and by Daniel P. Friedman and David S. Wise.

Applications.

Delayed evaluation is used particularly in functional programming languages. When using delayed evaluation, an expression is not evaluated as soon as it gets bound to a variable, but when the evaluator is forced to produce the expression's value. That is, a statement such as codice_1 (i.e. the assignment of the result of an expression to a variable) clearly calls for the expression to be evaluated and the result placed in codice_2, but what actually is in codice_2 is irrelevant until there is a need for its value via a reference to codice_2 in some later expression whose evaluation could itself be deferred, though eventually the rapidly growing tree of dependencies would be pruned to produce some symbol rather than another for the outside world to see.  Delayed evaluation has the advantage of being able to create calculable infinite lists without infinite loops or size matters interfering in computation. For example, one could create a function that creates an infinite list (often called a "stream") of Fibonacci numbers. The calculation of the "n"-th Fibonacci number would be merely the extraction of that element from the infinite list, forcing the evaluation of only the first n members of the list.  For example, in the Haskell programming language, the list of all Fibonacci numbers can be written as: In Haskell syntax, "codice_5" prepends an element to a list, codice_6 returns a list without its first element, and codice_7 uses a specified function (in this case addition) to combine corresponding elements of two lists to produce a third.  Provided the programmer is careful, only the values that are required to produce a particular result are evaluated. However, certain calculations may result in the program attempting to evaluate an infinite number of elements; for example, requesting the length of the list or trying to sum the elements of the list with a fold operation would result in the program either failing to terminate or running out of memory.

Control structures.

In almost all common "eager" languages, "if" statements evaluate in a lazy fashion. evaluates (a), then if and only if (a) evaluates to true does it evaluate (b), otherwise it evaluates (c). That is, either (b) or (c) will not be evaluated. Conversely, in an eager language the expected behavior is that will still evaluate (e) when computing the value of f(d, e) even though (e) is unused in function f. However, user-defined control structures depend on exact syntax, so for example (i) and (j) would both be evaluated in an eager language. While in a lazy language, (i) or (j) would be evaluated, but never both.  Lazy evaluation allows control structures to be defined normally, and not as primitives or compile-time techniques. If (i) or (j) have side effects or introduce run time errors, the subtle differences between (l) and (l') can be complex. It is usually possible to introduce user-defined lazy control structures in eager languages as functions, though they may depart from the language's syntax for eager evaluation: Often the involved code bodies (like (i) and (j)) need to be wrapped in a function value, so that they are executed only when called.  Short-circuit evaluation of Boolean control structures is sometimes called "lazy".

Working with infinite data structures.

Many languages offer the notion of "infinite data-structures". These allow definitions of data to be given in terms of infinite ranges, or unending recursion, but the actual values are only computed when needed. Take for example this trivial program in Haskell: numberFromInfiniteList :: Int -> Int numberFromInfiniteList n = infinity!! n - 1  main = print $ numberFromInfiniteList 4 In the function numberFromInfiniteList, the value of infinity is an infinite range, but until an actual value (or more specifically, a specific value at a certain index) is needed, the list is not evaluated, and even then it is only evaluated as needed (that is, until the desired index.)

Avoiding excessive effort.

A compound expression might be in the form "EasilyComputed or LotsOfWork" so that if the easy part gives true a lot of work could be avoided. For instance, suppose a large number N is to be checked to determine if it is a prime number and a function IsPrime(N) is available, but alas, it can require a lot of computation to evaluate. Perhaps "N=2 or [Mod(N,2)≠0 and IsPrime(N)]" will help if there are to be many evaluations with arbitrary values for N.

Avoidance of error conditions.

A compound expression might be in the form "SafeToTry and Expression" whereby if "SafeToTry" is false there should be no attempt at evaluating the "Expression" lest a run-time error be signalled, such as divide-by-zero or index-out-of-bounds, etc. For instance, the following pseudocode locates the last non-zero element of an array: Should all elements of the array be zero, the loop will work down to L = 0, and in this case the loop must be terminated without attempting to reference element zero of the array, which does not exist.

Other uses.

In computer windowing systems, the painting of information to the screen is driven by "expose events" which drive the display code at the last possible moment. By doing this, windowing systems avoid computing unnecessary display content updates.  Another example of laziness in modern computer systems is copy-on-write page allocation or demand paging, where memory is allocated only when a value stored in that memory is changed.  Laziness can be useful for high performance scenarios. An example is the Unix mmap function, which provides "demand driven" loading of pages from disk, so that only those pages actually touched are loaded into memory, and unneeded memory is not allocated.  MATLAB implements "copy on edit", where arrays which are copied have their actual memory storage replicated only when their content is changed, possibly leading to an "out of memory" error when updating an element afterwards instead of during the copy operation.

Implementation.

Some programming languages delay evaluation of expressions by default, and some others provide functions or special syntax to delay evaluation. In Miranda and Haskell, evaluation of function arguments is delayed by default. In many other languages, evaluation can be delayed by explicitly suspending the computation using special syntax (as with Scheme's "codice_8" and "codice_9" and OCaml's "codice_10" and "codice_11") or, more generally, by wrapping the expression in a thunk. The object representing such an explicitly delayed evaluation is called a "lazy future." Raku uses lazy evaluation of lists, so one can assign infinite lists to variables and use them as arguments to functions, but unlike Haskell and Miranda, Raku does not use lazy evaluation of arithmetic operators and functions by default.

Laziness and eagerness.

Controlling eagerness in lazy languages.

In lazy programming languages such as Haskell, although the default is to evaluate expressions only when they are demanded, it is possible in some cases to make code more eager—or conversely, to make it more lazy again after it has been made more eager. This can be done by explicitly coding something which forces evaluation (which may make the code more eager) or avoiding such code (which may make the code more lazy). "Strict" evaluation usually implies eagerness, but they are technically different concepts.  However, there is an optimisation implemented in some compilers called strictness analysis, which, in some cases, allows the compiler to infer that a value will always be used. In such cases, this may render the programmer's choice of whether to force that particular value or not, irrelevant, because strictness analysis will force strict evaluation.  In Haskell, marking constructor fields strict means that their values will always be demanded immediately. The codice_12 function can also be used to demand a value immediately and then pass it on, which is useful if a constructor field should generally be lazy. However, neither of these techniques implements "recursive" strictness—for that, a function called codice_13 was invented.  Also, pattern matching in Haskell 98 is strict by default, so the codice_14 qualifier has to be used to make it lazy.

Simulating laziness in eager languages.

Python.

In Python 2.x the codice_15 function computes a list of integers. The entire list is stored in memory when the first assignment statement is evaluated, so this is an example of eager or immediate evaluation:  »> r = range(10) »> print r [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] »> print r[3] 3 In Python 3.x the codice_15 function returns a special range object which computes elements of the list on demand. Elements of the range object are only generated when they are needed (e.g., when codice_17 is evaluated in the following example), so this is an example of lazy or deferred evaluation: »> r = range(10) »> print(r) range(0, 10) »> print(r[3]) 3  In Python 2.x is possible to use a function called codice_18 which returns an object that generates the numbers in the range on demand. The advantage of codice_19 is that generated object will always take the same amount of memory. »> r = xrange(10) »> print(r) xrange(10) »> lst = [x for x in r] »> print(lst) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] From version 2.2 forward, Python manifests lazy evaluation by implementing iterators (lazy sequences) unlike tuple or list sequences. For instance (Python 2):  »> numbers = range(10) »> iterator = iter(numbers) »> print numbers [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] »> print iterator <listiterator object at 0xf7e8dd4c> »> print iterator.next() 0

.NET Framework.

In the.NET Framework it is possible to do lazy evaluation using the class System.Lazy<T>. The class can be easily exploited in F# using the lazy keyword, while the force method will force the evaluation. There are also specialized collections like Microsoft.FSharp.Collections.Seq that provide built-in support for lazy evaluation.  let fibonacci = Seq.unfold (fun (x, y) -> Some(x, (y, x + y))) (0I,1I) fibonacci |> Seq.nth 1000  In C# and VB.NET, the class System.Lazy<T> is directly used.  public int Sum()  Or with a more practical example:  // recursive calculation of then'th fibonacci number public int Fib(int n)  public void Main()  Another way is to use the yield keyword:  // eager evaluation public IEnumerable<int> Fibonacci(int x)  // lazy evaluation public IEnumerable<int> LazyFibonacci(int x)

In programming language theory, lazy evaluation, or call-by-need is an evaluation strategy which delays the evaluation of an expression until its value is needed (non-strict evaluation) and which also avoids repeated evaluations (sharing). The sharing can reduce the running time of certain functions by an exponential factor over other non-strict evaluation strategies, such as call-by-name.

在程序语言理论中,惰性求值(英语:Lazy Evaluation),又译为惰性计算、懒惰求值,也称为传需求调用(call-by-need),是一个计算机编程中的一个概念,目的是要最小化计算机要做的工作。它有两个相关而又有区别的含意,可以表示为“延迟求值”和“最小化求值”,本条目专注前者,后者请参见最小化计算条目。除可以得到性能的提升外,惰性计算的最重要的好处是它可以构造一个无限的数据类型。


Tables of styled letters and digits.

These tables show all styled forms of Latin and Greek letters, symbols and digits in the Unicode Standard, with the normal unstyled forms of these characters shown with a cyan background (the basic unstyled letters may be serif or sans-serif depending upon the font). The styled characters are mostly located in the Mathematical Alphanumeric Symbols block, but the 24 characters in cells with a pink background are located in the letterlike symbols block, for example, R () is at U+211B rather than the expected U+1D4AD which is reserved. In the code charts for the Unicode Standard, the reserved code points corresponding to the pink cell are annotated with the name and code point of the correct character. There are a few characters which have names that suggest that they should belong in the tables below, but in fact do not because their official character names are misnomers:

Latin letters.

The Unicode values of the characters in the tables below, except those shown with or index values of '–', are obtained by adding the base values from the "U+" header row to the index values in the left column (both values are hexadecimal).

Greek letters and symbols.

Digits.

The Unicode values of the characters in the tables below are obtained by adding the hexadecimal base values from the "U+" header row to the index values in the left column.

History.

The following Unicode-related documents record the purpose and process of defining specific characters in the Mathematical Alphanumeric Symbols block:

Mathematical Alphanumeric Symbols is a Unicode block comprising styled forms of Latin and Greek letters and decimal digits that enable mathematicians to denote different notions with different letter styles. The letters in various fonts often have specific, fixed meanings in particular areas of mathematics. By providing uniformity over numerous mathematical articles and books, these conventions help to read mathematical formulas.

数学字母数字符号(Mathematical Alphanumeric Symbols)是Unicode的一个码位区段(英语:Unicode block)的正式名称。包含不同字型风格的拉丁字母、希腊字母与十进制数字在数学中用作不同指代含义的符号。例如,黑板粗体(blackboard bold),Unicode中使用的对应术语是双线体(double-struck)。


波蒂奇克里克 (阿拉斯加州)

Geography.

The Portage Creek CDP is located at (58.906088, -157.716758), at the confluence of Portage Creek with the Nushagak River.  According to the United States Census Bureau, the CDP has a total area of, all of it land.

Demographics.

Portage Creek first appeared on the 1980 U.S. Census as a census-designated place (CDP). In 1990, it lost that designation and was reclassified as an unincorporated Alaskan Native Village Statistical Area (ANVSA). In 2000, it regained its status as a census-designated place (CDP).  As of the census of 2000, there were 36 people, 7 households, and 4 families residing in the CDP. The population density was 2.7 people per square mile (1.1/km2). There were 22 housing units at an average density of 1.7/sq mi (0.6/km2). The racial makeup of the CDP was 13.89% White and 86.11% Native American.  There were 7 households out of which 57.1% had children under the age of 18 living with them, 71.4% were married couples living together, and 28.6% were non-families. 28.6% of all households were made up of individuals and none had someone living alone who was 65 years of age or older. The average household size was 5.14 and the average family size was 6.60.  In the CDP, the population was spread out with 52.8% under the age of 18, 11.1% from 18 to 24, 25.0% from 25 to 44, 5.6% from 45 to 64, and 5.6% who were 65 years of age or older. The median age was 14 years. For every 100 females, there were 111.8 males. For every 100 females age 18 and over, there were 88.9 males.  The median income for a household in the CDP was $41,250, and the median income for a family was $41,250. Males had a median income of $0 versus $16,250 for females. The per capita income for the CDP was $8,010. There were no families and none of the population living below the poverty line, including no under eighteens and none of those over 64.  As of November 2013 there were only 2 year-round residents of Portage Creek.

Education.

It was previously served by the Portage Creek School, operated by the Southwest Region School District.

Portage Creek is a census-designated place (CDP) in Dillingham Census Area, Alaska, United States. The population was 2 at the 2010 census, down from 36 at the 2000 census.

波蒂奇克里克(英语:Portage Creek)是位于美国阿拉斯加州迪灵汉人口普查区的一个非建制地区和人口普查指定地区。根据2010年美国人口普查,该地共人口2人,而该地的面积约为33.30平方千米。


Taxonomy.

Some authorities classify the intermediate egret in its own monotypic genus, "Mesophoyx", while others place it with the smaller egrets in "Egretta".  There are three recognised subspecies, and these are sometimes raised in to species:  "A.i. intermedia" differs from "A.i. brachyrhyncha" and "A. i. plumifera" by having a black bill when in breeding plumage, while "A.i. plumata" has a yellow-and-pink bill and "A. i. brachyrhyncha" has much yellower lores and face. A further difference between the nominate subspecies and the "yellow-billed" subspecies are that the "intermediate" subspecies has black at the top of the legs compared to reddish in the yellow-billed egret.

Description.

This species, as its scientific name implies, is intermediate in size between the great egret and smaller white egrets like the little egret and cattle egret, though nearer to little than great. It is about long with a wingspan and weighs c., with all-white plumage, generally dark legs and a thickish yellow bill. Breeding birds may have a reddish or black bill, greenish yellow gape skin, loose filamentous plumes on their breast and back, and dull yellow or pink on their upper legs (regional variations). The sexes are similar.

Differences from great egret.

The non-breeding colours are similar, but the intermediate is smaller, with neck length a little less than body length, a slightly domed head, and a shorter, thicker bill. The great egret has a noticeable kink near the middle of its neck, and the top of its longer bill nearly aligns with the flat top of its head. Close up, great egret's gape line extends behind the eye, while the intermediate's is less pointed and ends below the eye. The intermediate tends to stalk upright with neck extended forward. The great is more patient, often adopting a sideways-leaning "one-eyed" stance.

Differences from little egret.

Little egrets have yellow-soled feet and black bills. They often run after fish in shallow water. Breeding birds have long nuptial plumes on the back of their heads.

Behaviour.

The intermediate egret stalks its prey methodically in shallow coastal or fresh water, including flooded fields. It eats fish, frogs, crustaceans and insects. It often nests in colonies with other herons, usually on platforms of sticks in trees or shrubs. Two to five eggs are laid, the clutch size varying with region.

The intermediate egret, median egret, smaller egret, or yellow-billed egret ("Ardea intermedia") is a medium-sized heron. Some taxonomists put the species in the genus "Egretta" or "Mesophoyx". It is a resident breeder from east Africa across the Indian subcontinent to Southeast Asia and Australia.

中白鹭(学名:)为鹭科苍鹭属的鸟类,俗名春锄。分布于非洲、印度、孟加拉国、缅甸、马来半岛、菲律宾、越南至日本、巽他群岛、马鲁古群岛、澳大利亚以及中国大陆的中国南部、西至陕西、甘肃、四川、云南、贵州、北至河南为夏候鸟、广东、海南、台湾为冬候鸟、偶见于北京等地,多生活于稻田、湖泊、沼泽及滩涂、筑巢于村寨附近的乔木和竹林上以及在贵州分布于海拔400-800m。该物种的模式产地在印度尼西亚爪哇。中白鹭是一种中型涉禽,大型鹭类,个体大小介于大白鹭和白鹭之间,略较白鹭为大。嘴和颈相对较白鹭短,嘴长而尖直,翅大而长,脚和趾均细长,胫部部分裸露,脚三趾在前一趾在后,中趾的爪上具梳状栉缘。雌雄同色。体形呈纺锤形,体羽疏松,具有丝状蓑羽,胸前有饰羽,头顶有的有冠羽,腿部被羽。虹膜黄色;嘴黑色;眼先裸露皮肤绿黄色;脚和趾黑色;冬季嘴黄色;嘴尖黑色;脚和趾黑色。大小量度:体长620-700毫米,嘴峰68-75毫米,翅800-383毫米,尾113-128毫米,跗跖110-116毫米。


History.

Building an airport in Tibet, which is termed in flying parlance as going over a "hump" in the Tibetan Plateau, has gone through a process of trial and error through many hazardous air routes and several fatal accidents during World War II. The first airport was built in May 1956, in the southwest of Damxung County at a height of. An Ilyushin Il-12 and a Convair CV-240-401 were the first aircraft that landed at Damxung airport from the north and south. They thus broke the jinx of the "forbidden air zone", and this was acclaimed a feat. It took almost nine more years before the first Beijing-Chengdu-Lhasa air route became operational in 1965.  In 1965 the Gonggar Airport was constructed. Damxung Airport was decommissioned later (converted into a race course) and the Lhasa Aviation Office was moved from Damxung to Gonggar Airport. This established the Gonngar Airport as the second airport in Tibet. Over the years, with more expansion of the facilities, Gonggar became the domestic hub in the Tibetan Plateau connecting many other airports in Tibet.

Geographic environment.

Gonggar Airport is in Gyazuling township of the Gonggar County. It is built in the county where Yarlung Tsangpo River (the Brahmaputra River) is very wide on the right bank (southern bank) of the river providing facilities for the runways. It is for this reason that the airport was constructed at this location, though away from Lhasa where space was a limitation. The airport lies to the west of Rawa-me, which is the capital of the county, at the entry of the Namrab Valley, from Tsetang. The tunnel and Lhasa Airport Expressway opened in July 2011.

Airport description.

At an elevation of above sea level, the airport is one of the highest in the world. Its runway, with airport rank 4E, at with a width of, is designed to handle wide-bodied aircraft in the thin Tibetan air. It has an area of with the passenger handling facilities of ticketing office, the baggage collection beltways and visitors gallery on the first floor of the new terminal building, and the departure lounge on the second floor with shopping malls, kiosks and restaurants. There are four aero bridges (one two-way bridge and three single-way bridges) to facilitate passengers to board and disembark from the aircraft. The airport began operation in 1965 with flights to Beijing and Chengdu commencing that March. Recent additions included the expansion of the existing terminal in 2004 and as a result the airport has the facility to check in 1,300 passengers per hour during peak hours.  The airport has parking facilities for five Airbus A340 or seven Boeing 757 aircraft.  The airport is connected to the rest of China, which includes cities such as Beijing, Chengdu, Shanghai, Guangzhou, Hong Kong, Chongqing, Xi'an, Xining, Kunming, Diqing and Chamdo Region. There is an international route connecting Kathmandu, Nepal and Lhasa.

Flight handling.

All flights to and from the Lhasa Gonggar Airport are handled by seven Chinese-based airlines: Air China, China Eastern, China Southern, Shenzhen, Hainan, Sichuan, and Tibet Airlines. During tourist season (roughly April to October), there can be as many as 40 domestic flights every week to and from Gonggar, carrying on average as many as 700,000 passengers every year. There is only one international route at present: a once or twice weekly (depending on the season) flight to and from Kathmandu. It is typically not possible to purchase air tickets directly from these carriers given the requirement of obtaining the necessary governmental travel permit, which is not the same as the visa to gain entry into the rest of mainland China. It was expected that this figure would reach 110,000 by the year 2010.  Pilots landing at Lhasa Gonggar Airport must be specially trained in handling manoeuvres at landing at the high altitude of. Incidentally, Nagqu Dagring Airport is expected to become the world's highest altitude airport by 2014 at 4,436 meters above sea level.  Given the frequency of strong air currents picking up in the afternoon, most flights into the airport are scheduled in the morning.  A night landing facility was created by fixing navigational lighting facilities on the runway at a cost of 99 million yuan (US$13.2 million) only in 2007. This adds to the handling capacity of the airport by about 40%. The night landing facility was commissioned on 14 November 2007 with the landing of an Airbus A319 aircraft of Air China carrying 90 passengers. This facility was made operational initially once a week on Wednesdays from Chengdu Shuangliu International Airport in Sichuan Province. With this facility the airport planned to handle 1.1 million passengers every year by 2010, as against 1.005 million in 2007.  The airport was able to accommodate an Airbus 330 overnight for the first time on April 11, 2017, a problem due to the airport's high altitude.

Infrastructure.

A new highway between Lhasa and the Gonggar Airport has been built by the Transportation Department of Tibet at a cost of RMB 1.5 billion yuan. It is a four-lane road of length. This road is part of the National Highway 318; it starts from the Lhasa railway station, passes through the Caina Township in Qushui County, terminates between the north entrance of the Gala Mountain Tunnel and the south bridge head of Lhasa River Bridge, and en route goes over the first overpass of Lhasa at Liuwu Overpass.

Lhasa Gonggar Airport (, ; ) is the airport serving Lhasa, the capital city of the Tibet Autonomous Region, China. It is about southwest of the city in Gyazhugling, Gonggar County of Shannan. The airport is close to the road to Tsetang, the seat of Nêdong District and the capital of Shannan.

拉萨贡嘎机场(;)位于中国西藏自治区山南市贡嘎县境内,是一座服务于自治区首府拉萨市的4E级民用机场。贡嘎机场位于拉萨西南,建于雅鲁藏布江河谷上,海拔3569.5米,距离拉萨市区97公里。


Background.

In 1963, under the 1950 Sino-Soviet Treaty of Friendship, Alliance and Mutual Assistance, the Soviet Union passed to China the necessary design details in order to produce s. The Chinese variant became known as the Type 033 Romeo class, of which China built a total of 84 between 1962 and 1984.  During the 1970s, China's ambition to create an indigenous submarine industry lead to the commissioning of Wuhan Ship Development and Design Institute (701 Institute) to design and build an improved submarine based on the Type 033 hull, named the Type 035 Ming class. Two Type 035 boats were completed by 1974.  Further improvements were deemed necessary and by the early 1980s a new and improved design, named the Type 035A Ming class were produced. The first of these improved "A" models entered service in 1982, with three more under construction. The latter three boats were completed and commissioned by 1990.  The Type 035G Ming class is the most numerous variant. A total of 12 were built and commissioned between 1990 and 1999. They were built with further improvements, especially in terms of noise reduction, weapons, sensors and crew living standards. The PLAN refer to this sub-class as, "new wine in an old bottle". Two boats of the Type 035A were upgraded to same standard as the Type 035G.  The most modern design variant is the Type 035B Ming class, which features a redesigned conning tower and portions of the hull, giving it a very similar appearance to the newer Type 039 submarines. Type 035B are capable of launching land attack cruise missiles from their torpedo tubes. A total of four boats were commissioned between 2000 and 2003.

Boats of the class.

The following are the pennant numbers of each boat, according to their type:

Accident.

In April 2003, the Ming-class submarine 361 suffered a mechanical failure that killed all 70 crew members on board during an exercise in the Yellow Sea between North Korea and China's Shandong Province. It was one of China's worst peacetime military disasters. The PLA Navy's Commander Shi Yunsheng and Political Commissar Yang Huaiqing were both dismissed as a result of the accident.

The Type 035 submarine (NATO reporting name: Ming class) is a class of diesel-electric submarines of the People's Liberation Army Navy. The Type 035 is a heavily improved redesign of the older Type 033 Romeo-class submarines, which were built in China from 1962 to 1984.

035型潜艇(北约代号:明级,英语:"Ming-class"),发展自033型潜艇,在1970年代由位于中国湖北武汉的武汉船舶设计院(701所)设计。035型潜艇换装了改进型柴电引擎,减少阻力的船壳,拥有更快的水下航行速度,并换装613所设计的H/SQZ-262型声纳。 改进通讯导航系统。最显著的特征是围壳形状的变化,中国至少建造了21艘以上035型潜艇。


History.

The roots of the university can be traced back to 1902, when the was established. Its first president was. In 1929 this school was renamed, and it was further renamed in 1944,.  In 1949, under Japan's new educational systems, the university was merged with Hyogo Normal School, Hyogo Junior Normal School, Kobe Technical College and Himeji High School, all of which were in Hyōgo Prefecture, leading to the creation of "Kobe University".  The university has since been expanded and has created new faculties to complement its main academic foundations, which have been strongly established in the fields of economics and commerce.

Campuses.

The university is formed by four campuses: Rokkodai, Kusunoki, Myodani, and Fukae. Rokkodai Campus is considered the main campus, and it comprises nine out of eleven faculties.

Academic rankings.

Kobe University is one of the leading universities in Japan. It can be seen in the several rankings such as shown below.

General rankings.

The university is ranked 10th in 2010 in the ranking "Truly Strong Universities" by Toyo Keizai. In another ranking, Japanese prep school ranked Shindai as the 11th best university in Japan.  In 2010 QS World University Rankings ranked Shindai 234th in the world. It is also ranked as the 26th best university in QS Asian University rankings.

Research performance.

Kobe University is one of the leading research institutions in Japan. According to Thomson Reuters, Shindai is the 14th best research university in Japan.  It especially has a high research standard in Social Science and Humanities.  Asahi Shimbun summarized the amount of academic papers in Japanese major legal journals by university, and Shindai was ranked 5th during 2005-2009. Economics is also a notable field for Shindai. According to RePec, Shindai is the 7th best Economics research university in Jan 2011.  In addition, Nikkei Shimbun on 2004/2/16 surveyed about the research standards in Engineering studies based on Thomson Reuters, and questionnaires to heads of 93 leading Japanese Research Centers, and Shindai was placed 12th (informative ability of research outcome 3rd) in this ranking.

Graduate school rankings.

Eduniversal ranked Shindai's MBA as 6th best in Japan in their MBA rankings. It also means 129th best in the world.  Shindai has one of the leading law schools in Japan as it was ranked 4th in 2009 (and 5th in 2011) in the passing rate of Japanese Bar Examination.

Alumni rankings.

Alumni of Shindai enjoy their good success in Japanese industries such as shown below.  According to the's 2010 rankings, graduates from Shindai have the 18th best employment rate in 400 major companies in Japan. By contrast, the alumni of Shindai's average salary is very high with the 10th best in Japan, according to the.  Shindai graduates were ranked 8th in Japan in the number of successful national CPA exam applicants.

Popularity and selectivity.

Shindai is a popular university in Japan. Its entrance examination is usually considered as very selective. It is ranked in top 10 in Japan.

Scholarships for international students.

Kobe university encourages international students to study at the university through a number of scholarships for eligible students. Some of them are:

, also known in the Kansai region as, is a leading Japanese national university located in the city of Kobe, in Hyōgo. It was established in 1949, but the academic origins of Kobe University trace back to the establishment of Kobe Higher Commercial School in 1902, which was renamed as Kobe University of Commerce, and Kobe University of Economics. Kobe University is one of the oldest and largest national universities in Japan, as well as one of the highest ranking national universities in the country. It comprises 14 graduate schools and 11 undergraduate faculties, and holds about 16,000 students enrolled in undergraduate and graduate programs. The institution welcomes overseas students, which accounted for a total of 1,303 students, as of 2018. It also has 3,685 staff members, including professors, associate professors and administrative officials.

神户大学(),简称神大(しんだい)、神户大(こうべだい),是一所位于日本兵库县的国立大学。


Education.

The formal education of the Aztecs was to train and teach young boys how to function in their society as warriors. The Aztecs had no standing army, so every boy not of noble birth was trained to become a warrior. All boys who were between the ages of ten and twenty years old would attend one of the two schools. These two schools were the Telpochcalli (the neighborhood school for commoners) and the Calmecac, the exclusive school for nobles. At the Telpochcalli students would learn the art of warfare, and would become warriors. At the Calmecac students would be trained to become military leaders, priests, government officials, etc. Trades such as farming and artisan skills were not taught at these schools.  At the age of 15, sons of commoners would be sent to a Telpochcalli within their neighborhood. Here, boys would be trained in the art of warfare and accustomed to military life. The instructors at these schools were veteran warriors who had experience in warfare and leadership. The schools focused on bravery and included a great deal of physical effort and intense pain to increase the strength and stamina of the students. Manual labor included transporting goods such as branches for firewood. The longer the student had attended the school, the more branches he would be expected to carry. This test of carrying firewood would be used to determine if the boy would do well in warfare.  Other manual labor tasks carried out from the Tepochcalli would be community projects. These projects would mainly consist of cleaning areas, building walls, digging canals, and farming. From these projects students would work hard to complete tasks, and gain physical experience needed to engage in warfare. The students of this school would also be used to transport shields, food, military supplies, weapons, armor, and wood to warriors on the battlefield. The reason for forcing the students to be near the battlefield was to make them fearless of warfare. Students were under heavy surveillance at all times. If a student was caught leaving training their punishment would be severe. Often, they would be beaten and their hair removed. By removing their hair they would remove any sign of them being a warrior. Drinking pulque was prohibited; if caught, the student could be beaten to death. Relationships outside of the school were also prohibited; if a student was caught sleeping with a woman, they would be beaten to death.

Life as a jaguar warrior.

Following the warrior's path was one of the few ways to change one's social status in Aztec culture. Eagle and Jaguar warriors were full-time warriors who worked for the city-state to protect merchants and the city itself. They were expected to be leaders and commanders both on and off the battlefield, and acted as sort of a police force for the city. Men who reached this rank were considered as nobles and elites of society, and were granted many of the same privileges as a noble. They were allowed to drink "pulque", have concubines, and dine at the royal palace. Jaguar warriors also participated in gladiatorial sacrifices.

Gladiatorial sacrifice.

The gladiatorial sacrifice was a giant spectacle the entire city would attend. The captives would be paraded in the streets followed by eagle and jaguar warriors to the sacrifice stone. The eagle and jaguar warriors would dance around the captives and display their shields and weapons to the crowds. Once they brought the captives to the sacrifice stone, they would be tied down to it to be ceremonially killed. The captives would be forced to drink "pulque" to intoxicate them. They would be painted and given a sword and a shield along with four cudgels to throw. The warriors would then attack the victim who was tied down to the sacrifice stone with an obsidian laced club. The club would be used for ceremonial use and would be decorated with feathers. He would be attacked by several warriors one at a time and then, if still alive, would be attacked by all four together. The warriors which fought during the gladiatorial sacrifice would be eagle and jaguar warriors. If the captive fought off all of them, he would then have to defend himself against a left handed warrior. If captives were not killed this way, then they would be killed the following day by the offering priests. The gladiatorial sacrifice was done as a ceremony, for the return of warriors with their captives. The gladiatorial sacrifices were held during the month of the Feast of the Flaying of Men.

Jaguar warriors or jaguar knights, "ocēlōtl" (singular) or "ocēlōmeh" (plural) were members of the Aztec military elite. They were a type of Aztec warrior called a "cuāuhocēlōtl". The word "cuāuhocēlōtl" derives from the eagle warrior "cuāuhtli" and the Jaguar Warrior "ocēlōtl". They were an elite military unit similar to the eagle warriors.

美洲豹战士或美洲豹武士(纳瓦特尔语:"ocēlōtl")为阿兹特克帝国的军队之一。他们与雕战士,皆为精锐的军事单位。他们的穿着有美洲豹的形象是因为他们相信美洲豹代表着晚天之神泰兹卡特里波卡()。美洲豹战士在战场中多身居在前线。许多雕像和图片(前和后哥伦比亚抄本),这些战士们都活了下来。他们在作战时拿着一种上面钉有黑曜石的木棒,称作Maquahuitl,而他们也会使用枪矛与投枪器。


Gameplay.

In "FreeCol" the player leads the colony of a European power from the arrival on the shore of the New World into the future, achieving victory by one of two possible victory conditions: either gaining independence by declaring independence and subsequently defeating the dispatched royal expeditionary force or by defeating the colonies of all the competing European powers by the year 1600. To be allowed to declare independence, at least 50% of the player's colonists must support independence. This is achieved by producing liberty bells; 200 liberty bells turn one colonist from being a royalist into being a rebel. To be able to defeat the royal expeditionary force the player must train and build a strong enough army of their own.  Another important factor are the numerous settlements of different Native American nations. Native settlements can be traded with to gain gold or they can be conquered for treasure. Native settlements can also teach the player's colonists and turn them into specialist. Specialists are considerably more productive when assigned in their trade. Most specialists can be trained for gold in Europe or come as settlers for free, but certain specialists can only be trained at certain native settlements.  "FreeCol" starts in 1492 with two colonists on a caravel on the ocean at the player's disposal. The player is the king's proxy and is supposed to lead the caravel to the shore and found a colony in the New World consisting of multiple settlements. The player gets additional colonists by producing food (200 food units in a settlement generates a new unit), by immigration from Europe, by converting the natives or by capturing unarmed units of competing European colonies.  The player may trade with Europe using various natural resources which are produced in settlements or acquired from trade with natives. In each settlement the player can also build up industrial buildings to convert raw materials into processed goods, which sell for more in Europe, providing a significant economic advance.

Units.

Founding fathers.

The founding fathers are characters that give a different bonus at the beginning of the play:

Reception.

In February 2007 FreeCol was SourceForge's Project of the Month. In 2008 Rock, Paper, Shotgun's game journalist Alec Meer had mixed feelings about FreeCol but still called it: "it's an (sic) remarkable accomplishment, and I'm very glad it's out there." and "FreeCol, though, is here right now, it's free, it's stable, it's pretty much feature-complete and unlike its parent it has multiplayer". In 2010 Alec Meer named FreeCol in Rock, Paper, Shotgun as a better alternative when he was confronted with the later commercial remake "".  FreeCol became a popular freeware title, which was for instance downloaded over 1,900,000 times on SourceForge alone, between January 2002 and April 2017.

FreeCol is a 4X video game, a clone of "Sid Meier's Colonization". "FreeCol" is free and open source software released under the GNU General Public License v2.

FreeCol是一款4X游戏,是1994年发行席德·梅尔的殖民的复制版。经GNU通用公共许可证发布,是为自由软件。


San Marino in the Eurovision Song Contest

圣马力诺在欧洲歌唱大赛之历年表现

History.

In June 2007, Radiotelevisione della Repubblica di San Marino (SMRTV), the Sammarinese public service broadcaster, indicated interest in joining the contest in the near future, all depending on the interest of the stockholders, especially Italian broadcaster RAI, which had been absent from the Contest since 1997. Five months later, the broadcaster confirmed its participation in the Eurovision Song Contest 2008 in Belgrade. The first Sammarinese entry in the Eurovision Song Contest was Miodio, with the Italian language song "Complice". San Marino holds the honour of being the 50th country to participate at Eurovision, participating 5th in the first semi-final of the contest. Miodio failed to qualify for the final, receiving just 5 points in total and coming last. SMRTV had originally planned to compete at the 2009 contest in Moscow, Russia, with the Sammarinese Minister of Culture announcing shortly after the 2008 contest that they had "good hopes to return". SMRTV announced that it would be reviewing the 2008 contest, and would have a decision on 2009 participation by the end of the year. It was then rumoured that the country would not be participating in the 2009 contest following reports that SMRTV would withdraw due to poor results at the 2008 contest, however SMRTV rebuked the claim and confirmed its interest in the 2009 contest. In the end, SMRTV announced that it would not participate in the 2009 contest, having already applied to enter. The broadcaster insisted that this was not due to the poor results of the previous year, but financial difficulties faced by SMRTV. San Marino did not return for the Eurovision Song Contest 2010, again stating financial reasons preventing participation. The broadcaster announced that it hoped to return to the competition in the future and discussed possible participation in the Junior Eurovision Song Contest.  After a two-year absence from the Contest, San Marino returned in 2011 with Italian singer Senit performing "Stand By", which failed to take the nation to the final. Between 2012 and 2014, San Marino sent Valentina Monetta to the contest on three consecutive occasions, which made her the first singer to participate in three consecutive contests since Udo Jürgens, who competed in 1964, 1965 and 1966 for Austria. Her entries in 2012 ("The Social Network Song") and 2013 ("Crisalide (Vola)") also failed to qualify San Marino to the final. However, in 2014, Monetta managed to bring San Marino to the final for the first time, where she placed 24th with the song "Maybe". In 2015, the nation once again failed to qualify to the final with the song "Chain of Lights" performed by Anita Simoncini and Michele Perniola. In 2016, San Marino failed to qualify with "I Didn't Know" sung by Turkish performer Serhat. 2017 marked Valentina Monetta's fourth time in the contest, however, her song "Spirit in the Night" (with Jimmie Wilson) placed last in the semi-final, tying San Marino's worst performance. This was only slightly improved upon in 2018 with Jessika and Jenifer Brening's second to last place finish with "Who We Are". In 2019 San Marino sent Serhat again with the song "Say Na Na Na ", finishing in 19th place with 77 points, giving San Marino its best result to date. SMRTV confirmed San Marino's participation at the 2020 Eurovision Song Contest on 25 May 2019.  The Sammarinese national broadcaster, San Marino RTV (SMRTV), broadcasts the event within San Marino and organises the selection process for the nation's entry. Throughout the years, this selection process has varied from an internal selection, where the broadcaster chooses the entry, to a national final with public input. For 2020, San Marino used a national final-type process titled "Digital Battle Eurovision". After selecting the Senhit internally, an online poll was open for two days from 7 March 2020 until 8 March 2020 in order to select the song she would perform in the 2020 contest. The winning song, "Freaky!" was announced on 9 March 2020. Later that month, however, the 2020 Contest was cancelled due to the pandemic of the Coronavirus (COVID-19).

Related involvement.

Heads of delegation.

The public broadcaster of each participating country in the Eurovision Song Contest assigns a head of delegation as the EBU's contact person and the leader of their delegation at the event. The delegation, whose size can greatly vary, includes a head of press, the contestants, songwriters, composers and backing vocalists, among others.

Jury members.

A five-member jury panel consisting of music industry professionals is made up for every participating country for the semi-finals and Grand Final of the Eurovision Song Contest, ranking all entries except for their own country's contribution. The juries' votes constitute 50% of the overall result alongside televoting.

Commentators and spokespersons.

For the show's broadcast on SMRTV, various commentators have been hired throughout the years to provide comment on the Concert in the local language. At Eurovision, after all points are calculated, the presenters of the show call upon each voting country to invite their respective spokesperson to announce the results of their vote on-screen. In 2014, San Marino RTV also provided an English commentary in its internet streaming, with John Kennedy O'Connor and Jamarie Milkovic directly from Copenhagen.

San Marino has participated in the Eurovision Song Contest 10 times, debuting in the 2008 contest, followed by participation from 2011 onward. Having failed to qualify in their first four attempts, San Marino qualified for the Eurovision final for the first time in 2014. Valentina Monetta represented San Marino in 2012, 2013 and 2014, making her the first Sanmarinese singer to participate in three consecutive contests. Her most recent representation in 2017 together with Jimmie Wilson, gave her the title of the woman with the most participations ever in the Eurovision Song Contest. In, Serhat managed to qualify, marking the second appearance of the country in a Eurovision final.

圣马力诺共参加过9次欧洲歌唱大赛(截至)。圣马力诺首次在参赛,并在之后一直参赛。前四次参赛中圣马力诺都没有进入决赛,在首次进入决赛。


Biography.

Alexander Dalgarno was born in London in 1928, and spent his childhood there. He was educated in mathematics and atomic physics at University College, London, earning a Ph.D. in theoretical physics in 1951. He was an academic at the Queen's University, Belfast from 1951 to 1967 where he worked with Sir David Bates and rose from assistant lecturer to professor. In the 1950s, he laid the foundations for long-range atomic interaction studies which are of critical importance for today's interest in Bose–Einstein condensates.  In 1967 he moved to Harvard to join their department of astronomy and held the positions of acting director of Harvard College Observatory, chairman of the department of astronomy, associate director of the Harvard-Smithsonian Center for Astrophysics and director of the Institute for Theoretical Atomic and Molecular Physics. Dalgarno's research covered three main areas: theoretical atomic and molecular physics, astrophysics and aeronomy (the study of the upper atmosphere). He made contributions in theoretical chemistry, scattering theory, atmospheric physics & chemistry and astrophysics and was the author of more than 600 publications. Sir David Bates wrote in 1988 that "There is no greater figure than Alex in the history of atomic physics and its applications." Known as the "father of molecular astrophysics", Dalgarno was also a physicist at the Smithsonian Astrophysical Observatory and was formerly the editor of the Astrophysical Journal Letters.  Dalgarno was also cited in the Nebula Award winning novel "The Quantum Rose" by Catherine Asaro, a science-fiction novel based on Asaro's doctoral work while she was a Ph.D student with Dalgarno.  He married Barbara Kane, from whom he was later divorced, and had four children.

Awards.

His work was recognized by many awards, including the prize of the International Academy of Quantum Molecular Science, the Davisson-Germer Prize of the American Physical Society (1980), the William F. Meggers Award of the Optical Society of America (1986), the Gold Medal of the Royal Astronomical Society (1986) and the Benjamin Franklin Medal in Physics from the Franklin Institute (2013).  He was a Fellow of the American Geophysical Union and the American Physical Society and a member of the U.S. National Academy of Sciences. He was elected a Fellow of the Royal Society in 1972 and awarded their prestigious Hughes Medal in 2002. He was also a member of the International Academy of Quantum Molecular Science.  In 1998, Asteroid 6941 was named Asteroid Dalgarno.

Alexander Dalgarno FRS (5 January 1928 – 9 April 2015) was a British physicist who was a Phillips Professor of Astronomy at Harvard University.

亚历山大·达尔加诺(英语:Alexander Dalgarno,1928年-1月5日-2015年-4月9日),英国物理学家,哈佛大学菲利普斯天文学教授。


History.

Dazhou's history goes back to the Eastern Han Dynasty when in 90 AD it was made a county by the name of Liweizhou ). Then until the Liao Dynasty its name was Zaidi (). During the Liao and Tang dynasties its name was again changed, this time to Tongzhou (). Finally in the Song Dynasty it was given its present name of Dazhou.  Notable people from Dazhou include the Three Kingdoms writer Chen Shou, Song Dynasty astronomer Zhang Sixun, and Ming and Qing Dynasty philosopher and educator Tang Zhen. Dazhou also made notable contributions to the Communist Revolution. Red Army heroes such as Xu Xiangqian, Li Xiannian, Xu Shiyou, Wang Weizhou (), and Zhang Aiping were all from or lived in Dazhou.  The partially preserved mausoleum complex (in particular, its gate towers, known as "que" of the Shen () family in Qu County, dating from the Han Dynasty, is a well-known architectural monument.

Geography and climate.

Dazhou is the easternmost prefecture-level division of the province, bordering Ankang and Hanzhong (both in Shaanxi) to the north, Chengkou County, Kai County, and Wanzhou District of Chongqing to the east, the Chongqing counties of Liangping and Dianjiang to the south, Guang'an to the southwest, Nanchong to the west, and Bazhong to the northwest. It is centrally located between Chongqing and Xi'an. The area is.  The terrain is largely mountainous (Daba Mountains and adjacent ranges).  Typical of the Sichuan Basin, Dazhou has a monsoon-influenced humid subtropical climate (Köppen "Cwa") and is largely mild and humid, with four distinct seasons. Winter is short, mild, and foggy, though actual precipitation is low. January averages and, while frost may occur, snow is rare. Summers are long, hot and humid, with highs often exceeding. The monthly daily average in July, the warmest month, is. Rainfall is light in winter and can be heavy in summer, and over 70% of the annual total occurs from May to September. The annual frost-free period lasts around 300 days.

Administration.

It is one of Sichuan's most populous cities with 5,468,097 residents as of 2010 census.

Economy.

Dazhou is an important river and land transportation hub for the region. Numerous national highways, expressways, and rail lines pass through Dazhou connecting it directly with major cities in China such as Chengdu, Xi'an, Wuhan, Guangzhou, Shenzhen, Beijing, etc., making it one of Sichuan's important trade centers.  Dazhou has numerous natural resources including large natural gas fields and an abundance of mineral resources such as salt, coal, manganese, lithium, and limestone. Major agricultural products include pork, beef, and tea. Other industries are chemical production, coal power, metallurgy, textiles, building materials, and processed food.

Tourism.

Dazhou is blessed with both cultural and natural attractions. There are several national and provincial cultural sites and many national and provincial protected forests and nature reserves. Xuanhan's Baili Gorges have scenery and rapids, leading to the nickname "Little Three Gorges". Mountains are this area's greatest attraction.

Points of interest.

In Dazhou, there is a residential building with 16 floors with a 20 metres tall electricity pylon on the roof.

Protest of January 2007.

Dazhou's Dazhu County was the site of a mass protest in January 2007.

Dazhou () is a prefecture-level city in the northeast corner of Sichuan province, China, bordering Shaanxi to the north and Chongqing to the east and south. As of 2010 census, Dazhou was home to 5,468,097 inhabitants whom 1,589,435 lived in the built-up ("or metro") area made of 2 urban districts.

达州市,简称达,是中华人民共和国四川省下辖的地级市,位于四川省东北部。市境东接重庆市,南连广安市,西邻南充市、巴中市,北界陕西省汉中市、安康市。地处大巴山南麓,川渝陕结合部,嘉陵江支流渠江流域。全市总面积16,588平方公里,常住人口559.77万,市人民政府驻通川区。达州因其丰富的天然气资源而有“中国气都、巴人故里”之称,是国家“川气东送”工程的起点站。2011年达州籍画家陈清泉国画《气壮山河》走进人民大会堂。


Etymology.

The Buryat name means "place covered with couch grass," and is derived from Mongolian word, meaning "couch grass".

Geography.

The region where Kyakhta stands is a natural location for Russo-Chinese trade. The Siberian River Routes connect the fur-bearing lands of Siberia to Lake Baikal. From there, the Selenga River valley is the natural route through the mountains southeast of Lake Baikal out onto the plains of Mongolia.

History.

Kyakhta was founded in 1727 soon after the Treaty of Kyakhta was negotiated just north at Selenginsk. It was the starting point of the boundary markers that defined what is now the northern border of Mongolia. Kyakhta's founder, the Serb Sava Vladislavich, established it as a trading point between Russia and the Qing Empire. The Manchus built Maimaicheng just south of Kyakhta on their side of the border. Before 1762, state caravans traveled from Kyakhta to Peking. After that date, trade was mostly by barter at Kyakhta-Maimaicheng, with merchants crossing the border to make their business. Kyakhta and Maimaicheng were visited by the famous English adventurer and engineer Samuel Bentham in 1782. He related that he was entertained by the commander of the Chinese city "with the greatest politeness which a stranger can meet with in any country whatever". At that time, the Russians sold furs, textiles, clothing, hides, leather, hardware, and cattle, while the Chinese sold silk, cotton stuffs, teas, fruits, porcelain, rice, candles, rhubarb, ginger, and musk. Much of the tea is said to have come from Yangloudong, a major center of tea production and trade near today's Chibi City, Hubei.  Kyakhta was crowded, unclean, ill-planned, and never came to reflect the wealth that flowed through it, although several Neoclassical buildings were erected in the 19th century, including a tea bourse (1842) and the Orthodox cathedral (1807–1817), both of which still stand. In 1996 the Voskreskenskaya church was being used a stable. It was from Kyakhta that Nikolay Przhevalsky, Grigory Potanin, Pyotr Kozlov, and Vladimir Obruchev set off on their expeditions into the interior of Mongolia and Xinjiang.  Town status was granted to Kyakhta in 1805.  After the entire Russian-Chinese frontier was opened to trade in 1860 and the Trans-Siberian and the Chinese Eastern Railways bypassed it, Kyakhta fell into decline. The town was renamed Troitskosavsk during the first part of the 20th century, but the original name was restored in 1935. Other sources have Troitskosavsk as a fort a short distance north, Troitskosavsk being the administrative and military center while Kyakhta was the trading post on the border.  In the mid-20th century, a branch railway was built from Ulan-Ude (on the Trans-Siberian) to Mongolia's Ulan Bator, and, eventually, to China, paralleling the old Kyakhta trade route. However, this railway crosses the Russian-Mongolian border not in Kyakhta itself, but in nearby Naushki.

Kyakhta Pidgin.

As the first market town on the border between the Russian and Chinese Empires, Kyakhta gave its name to the so-called Kyakhta Russian–Chinese Pidgin, a contact language that was used by Russian and Chinese traders to communicate.

Administrative and municipal status.

Within the framework of administrative divisions, Kyakhta serves as the administrative center of Kyakhtinsky District. As an administrative division, it is, together with one rural locality (the settlement of Sudzha), incorporated within Kyakhtinsky District as the Town of Kyakhta. As a municipal division, the Town of Kyakhta is incorporated within Kyakhtinsky Municipal District as Kyakhta Urban Settlement.

Economy.

Kyakhta's economy today relies mainly on its status as an important center for trade between Russia, China, and Mongolia, located on the highway from the republic's capital of Ulan-Ude to the Mongolian capital of Ulan Bator. It also has textile, lumber, and food-processing plants.

Culture.

Kyakhta is home to the Damdin Sükhbaatar memorial museum.

Climate.

Kyakhta has a humid continental climate (Köppen climate classification "Dwb") with dry, severely cold winters and warm, moist summers.

Town name in other languages.

In Mongolian, Kyakhta was formerly known as ("Ar Khiagt", lit. "North Kyakhta"); Altanbulag (then, Maimaicheng) across the border was ("Övör Khiagt", lit. "South Kyakhta"). When the town was known as Troitskosavsk, its name in Mongolian was ("Deed Šhivee").

Kyakhta (, ;, ;, "Khiagt") is a town and the administrative center of Kyakhtinsky District in the Republic of Buryatia, Russia, located on the Kyakhta River near the Mongolia–Russia border. The town stands directly opposite the Mongolian border town of Altanbulag. Population: From 1727 it was the border crossing for the Kyakhta trade between Russia and China.

恰克图(;,"Khyaagta"),今俄罗斯布里亚特共和国的一个临近蒙古国的城市。2002年的人口普查这里人口有18391人。恰克图位于现在的俄蒙边界界河的北岸,和南岸的蒙古国的阿勒坦布拉格(清代称买卖城或Maimaicheng)隔河相望。这里原是清代的中国商人对俄贸易的重要城市。


Early life in Birmingham, 1783–1804.

Cox was born on 29 April 1783 on Heath Mill Lane in Deritend, then an industrial suburb of Birmingham. His father was a blacksmith and whitesmith about whom little is known, except that he supplied components such as bayonets and barrels to the Birmingham gun trade. Cox's mother was the daughter of a farmer and miller from Small Heath to the east of Birmingham. Early biographers record that "she had had a better education than his father, and was a woman of superior intelligence and force of character." Cox was initially expected to follow his father into the metal trade and take over his forge, but his lack of physical strength led his family to seek opportunities for him to develop his interest in art, which is said to have first become apparent when the young Cox started painting paper kites while recovering from a broken leg.  By the late 18th century Birmingham had developed a network of private academies teaching drawing and painting, established to support the needs of the town's manufacturers of luxury metal goods, but also encouraging education in fine art, and nurturing the distinctive tradition of landscape art of the Birmingham School. Cox initially enrolled in the academy of Joseph Barber in Great Charles Street, where fellow students included the artist Charles Barber and the engraver William Radclyffe, both of whom would become important lifelong friends.  At the age of about 15 Cox was apprenticed to the Birmingham painter Albert Fielder, who produced portrait miniatures and paintings for the tops of snuffboxes from his workshop at 10 Parade in the northwest of the town. Early biographers of Cox record that he left his apprenticeship after Feidler's suicide, with one reporting that Cox himself discovered his master's hanging body, but this is probably a myth as Fielder is recorded at his address in Parade as late as 1825. At some time during mid-1800 Cox was given work by William Macready the elder at the Birmingham Theatre, initially as an assistant grinding colours and preparing canvases for the scene painters, but from 1801 painting scenery himself and by 1802 leading his own team of assistants and being credited in plays' publicity.

London, 1804–1814.

In 1804 Cox was promised work by the theatre impresario Philip Astley and moved to London, taking lodgings in 16 Bridge Row, Lambeth. Although he was unable to get employment at Astley's Amphitheatre it is likely that he had already decided to try to establish himself as a professional artist, and apart from a few private commissions for painting scenery his focus over the next few years was to be on painting and exhibiting watercolours. While living in London, Cox married his landlord's daughter, Mary Agg and the couple moved to Dulwich in 1808. In 1805 he made his first of many trips to Wales, with Charles Barber, his earliest dated watercolours are from this year. Throughout his lifetime he made numerous sketching tours to the Home Counties, North Wales, Yorkshire, Derbyshire and Devon.  Cox exhibited regularly at the Royal Academy from 1805. His paintings never reached high prices, so he earned his living mainly as a drawing master. His first pupil, Colonel the Hon.H. Windsor (the future Earl of Plymouth) engaged him in 1808, Cox went on to acquire several other aristocratic and titled pupils. He also went on to write several books, including: "Ackermanns' New Drawing Book" (1809); "A Series Of Progressive Lessons" (1811); "Treatise on Landscape Painting" (1813); and "Progressive Lessons on Landscape" (1816). The ninth and last edition of his series "Progressive Lessons", was published in 1845.  By 1810 he was elected President of the Associated Artists in Water Colour. In 1812, following the demise of the Associated Artists, he was elected as associate of the Society of Painters in Water Colour (the old Water Colour Society). He was elected a Member of the Society in 1813, and exhibited there every year (except 1815 and 1817) until his death.

Hereford, 1814–1827.

In the summer of 1813 Cox was appointed as the drawing master of the Royal Military College in Farnham, Surrey, but he resigned shortly afterwards, finding little sympathy with the atmosphere of a military institution. Soon after that he applied to a newspaper advertisement for a position as drawing master for Miss Crouchers' School for Young Ladies in Hereford and in Autumn 1814 moved to the town with his family. Cox taught at the school in Widemarsh Street until 1819, his substantial salary of £100 per year requiring only two day's work per week, allowing time for painting and the taking of private pupils.  Cox's reputation as both a painter and a teacher had been building over previous years, as indicated by his election as a member of the Society of Painters in Water Colours and his inclusion in John Hassell's 1813 book "Aqua Pictura", which claimed to present works by "all of the most approved water coloured draftsmen". The depression that accompanied the end of the Napoleonic Wars had caused a contraction in the art market, however, and by 1814 Cox had been very short of money, requiring a loan from one of his pupils to pay even for the move to Hereford. Despite its financial advantages and its proximity to the scenery of North Wales and the Wye Valley, the move to Hereford marked a retreat in terms of his career as a painter: he sent few works to the annual exhibition of the Society of Painters in Water Colours during his first years away from London and not until 1823 would he again contribute more than 20 pictures.  Between 1823 and 1826 he had Joseph Murray Ince as a pupil.

London, 1827–1841.

He made his first trip to the Continent, to Belgium and the Netherlands in 1826 and subsequently moved to London the following year.  He exhibited for the first time with the Birmingham Society of Artists in 1829, and with the Liverpool Academy in 1831. In 1839, two of Cox's watercolours were bought from the Old Water Colour Society exhibition by the Marquis of Conynha for Queen Victoria.

Birmingham, 1841–1859.

In May 1840 Cox wrote to one of his Birmingham friends: "I am making preparations to sketch in oil, and also to paint, and it is my intention to spend most of my time in Birmingham for the purpose of practice". Cox had been considering a return to painting in oils since 1836 and in 1839 had taken lessons in oil painting from William James Müller, to whom he had been introduced by mutual friend George Arthur Fripp. Hostility between the Society of Painters in Water Colours and the Royal Academy made it difficult for an artist to be recognised for work in both watercolour and oil in London, however, and it is likely that Cox would have preferred to explore this new medium in the more supportive environment of his home town. By the early 1840s his income from sales of his watercolours was sufficient to allow him to abandon his work as a drawing master, and in June 1841 he moved with his wife to Greenfield House in Harborne, then a village on Birmingham's south western outskirts. It was this move that would enable the higher levels of freedom and experimentation that were to characterise his later work. In Harborne, Cox established a steady routine – working in watercolour in the morning and oils in the afternoon. He would visit London every spring to attend the major exhibitions, followed by one or more sketching excursions, continuing the pattern that he had established in the 1830s. From 1844 these tours evolved into a yearly trip to Betws-y-Coed in North Wales to work outdoors in both oil and watercolour, gradually becoming the focus for an annual summer artists colony that continued until 1856 with Cox as its "presiding genius."  Cox's experience of trying to exhibit his oils in London was short and unsuccessful: in 1842 he made his only submission to the Society of British Artists; one oil painting was exhibited at each of the British Institution and the Royal Academy in 1843; and two oil paintings were exhibited at the Royal Academy in 1844 – the last that would be exhibited in London during his lifetime.  Cox showed regularly at the Birmingham Society of Arts and its successor, the Birmingham Society of Artists, becoming a member in 1842.  Cox suffered a stroke on 12 June 1853 that temporarily paralysed him, and permanently affected his eyesight, memory and coordination.  By 1857 however, his eyesight had deteriorated. An exhibition of his work was arranged in 1858 by the Conversazione Society Hampstead, and in 1859 a retrospective exhibition was held at the German Gallery Bond Street, London. Cox died several months later. He was buried in the churchyard of St Peters, Harborne, Birmingham, under a chestnut tree, alongside his wife Mary.

Work.

Early work.

In the spring of 1811 Cox made a small number of notable works in oils during a visit to Hastings with his family. It is not known why he didn't continue working in this medium at the time, but the five known surviving examples were described in 1969 as "surely some of the most brilliant examples of the genre in England".

Mature work.

Cox reached artistic maturity after his move to Hereford in 1814. Although only two major watercolours can confidently be traced to the period between Cox's arrival in the town and the end of the decade, both of these – "Butcher's Row, Hereford" of 1815 and "Lugg Meadows, near Hereford" of 1817 – mark advances on his earlier work.

Later work.

Cox's later work produced after his move to Birmingham in 1841 was marked by simplification, abstraction and a stripping down of detail. His art of the period combined the breadth and weight characteristic of the earlier English watercolour school, together with a boldness and freedom of expression comparable to later impressionism. His concern with capturing the fleeting nature of weather, atmosphere and light was similar to that of John Constable, but Cox stood apart from the older painter's focus on capturing material detail, instead employing a high degree of generalisation and a focus on overall effect.  The quest for character over precision in representing nature was an established characteristic of the Birmingham School of landscape artists with which Cox had been associated early in his life, and as early as 1810 Cox's work had been criticised for its "sketchiness of finish" and "cloudy confusion of objects", which were held to betray "the coarseness of scene-painting". During the 1840s and 1850s Cox took this "peculiar manner" to new extremes, incorporating the techniques of the sketch into his finished works to a far greater degree.  Cox's watercolour technique of the 1840s was sufficiently different from his earlier methods to need explanation to his son in 1842, despite the fact that his son had been helping him teach and paint since 1827. The materials used for his later works in watercolour also differed from his earlier periods: he used black chalk instead of graphite pencil as his primary drawing medium, and the rough and absorbent "Scotch" wrapping paper for which he became well-known – both of these were related to his development of a rougher and freer style.

Influence and legacy.

By the 1840s Cox, alongside Peter De Wint and Copley Fielding, had become recognised as one of the leading figures of the English landscape watercolour style of the first half of the 19th century. This judgement was complicated by reaction to the rougher and bolder style of Cox's later Birmingham work, which was widely ignored or condemned. While by this time De Wint and Fielding were essentially continuing in a long-established tradition, Cox was creating a new one.  A group of young artists working in Cox's watercolour style emerged well before his death, including William Bennett, David Hall McKewan and Cox's son David Cox Jr.. By 1850 Bennett in particular had become recognised as "perhaps the most distinguished among the landscape painters" for his Cox-like vigorous and decisive style. Such early followers concentrated on the example of Cox's more moderate earlier work and steered clear of what were then seen as the excesses of Cox's later years. During a period dominated by sleek and detailed picturesque landscape, however, they were still condemned by publications such as "The Spectator" as "the 'blottesque' school", and failed to establish themselves as a cohesive movement.  John Ruskin in 1857 condemned the work of the Society of Painters in Water-colours as "a kind of potted art, of an agreeable flavour, suppliable and taxable as a patented commodity", excluding only the late work of Cox, about which he wrote "there is not any other landscape which comes near these works of David Cox in simplicity or seriousness".  An 1881 book, "A Biography of David Cox: With Remarks on His Works and Genius", was based on a manuscript by Cox's friend William Hall, edited and expanded by John Thackray Bunce, editor of the Birmingham Daily Post.  There are two Blue Plaque memorials commemorating him at 116 Greenfield Road, Harborne, Birmingham,, and at 34 Foxley Road, Kennington, London, SW9, where he lived from 1827.. It can also be seen at the David Cox exhibition in Birmingham.  His pupils included Birmingham architectural artist, Allen Edward Everitt (1824–1882).  A bust of Cox is in the Royal Birmingham Society of Artists' gallery.

Public collections.

Several of his works are in Birmingham Museum & Art Gallery, having been donated by Joseph Henry Nettlefold, on the condition it opened on Sundays. His work is also held at the Louvre, British Museum, Tate Gallery, Victoria and Albert Museum, and in Manchester, Newcastle, Liverpool, Edinburgh, Oxford and Cambridge. The Lady Lever Art Gallery, Port Sunlight shows a number of Cox's watercolours bought by Lever through James Orrock. Some of them have since been confirmed as forgeries. American collections holding Cox's work include The Metropolitan Museum of Art, The National Gallery of Art, Fine Arts Museums of San Francisco, Cleveland Art Museum, Fogg Art Museum, Rhode Island School of Design, High Museum of Art, Atlanta, Princeton University Art Museum, and The Huntington Library.  In 1983, an exhibition celebrating the bicentenary of the artist's birth was organized by the Birmingham Museums and Art Gallery and curated by Stephen Wildman. The exhibition traveled to the Victoria and Albert Museum, London, in the same year. An exhibition of his work was held at the Yale Center for British Art in the US in 2008, traveling to Birmingham in 2009.

David Cox (29 April 1783 – 7 June 1859) was an English landscape painter, one of the most important members of the Birmingham School of landscape artists and an early precursor of Impressionism.

大卫·考克斯(David Cox 1783年-4月29日-1859年-6月7日)是一名英格兰风景画家,是伯明翰画派的成员,早期印象派画家。他以绘制水彩画出名,但也绘制过300多幅油画。