History.

The first interceptor squadrons were formed during World War I to defend London against attacks by Zeppelins and later against fixed-wing long-range bombers. Early units generally used aircraft withdrawn from front-line service, notably the Sopwith Pup. They were told about their target's location before take-off from a command centre in the Horse Guards building. The Pup proved to have too low performance to easily intercept Gotha G.IV bombers, and the superior Sopwith Camels supplanted them.  The term "interceptor" was in use by 1929. Through the 1930s, bomber aircraft speeds increased so much that conventional interceptor tactics appeared impossible. Visual and acoustic detection from the ground had a range of only a few miles, which meant that an interceptor would have insufficient time to climb to altitude before the bombers reached their targets. Standing combat air patrols were possible but only at great cost. The conclusion at the time was that "the bomber will always get through".  The invention of radar made possible early, long-range detection of aircraft on the order of, both day and night and in all weather. A typical bomber might take twenty minutes to cross the detection zone of early radar systems, time enough for interceptor fighters to start up, climb to altitude and engage the bombers. Ground controlled interception required constant contact between the interceptor and the ground until the bombers became visible to the pilots and nationwide networks like the Dowding system were built in the late 1930s to coordinate these efforts.  The introduction of jet power increased speeds from perhaps to in a step and roughly doubled operational altitudes. Although radars also improved in performance, the gap between offense and defense was dramatically reduced. Large attacks could so confuse the defense's ability to communicate with pilots that the classic method of manual ground controlled interception was increasingly seen as inadequate. In the United States, this led to the introduction of the Semi-Automatic Ground Environment to computerize this task, while in the UK it led to enormously powerful radars to improve detection time  The introduction of the first useful surface-to-air missiles in the 1950s obviated the need for fast reaction time interceptors as the missile could launch almost instantly. Air forces increasingly turned to much larger interceptor designs, with enough fuel for longer endurance, leaving the point-defense role to the missiles. This led to the abandonment of a number of short-range designs like the Avro Arrow and Convair F-102 in favor of much larger and longed-ranged designs like the North American F-108 and MiG-25. Only the USSR seriously continued interceptor design after the 1960s, as only the USAF continued to make use of a powerful strategic bomber force. In the 1950s, during the Cold War, a strong interceptor force was crucial for the great powers as the best means to defend against an unexpected nuclear attack by strategic bombers. Hence, for a brief period of time they faced rapid development. At the end of the 1960s, a nuclear attack became unstoppable with the introduction of ballistic missiles capable of approaching from outside the atmosphere at speeds as high as 5–7 km/s. The doctrine of mutually assured destruction replaced the trend of defense strengthening, making interceptors less strategically logical. The utility of interceptors waned as the role merged with that of the heavy air superiority fighter, which was dominant in military thinking.

Design.

The interceptor mission is, by its nature, a difficult one. Consider the desire to protect a single target from attack by long-range bombers. The bombers have the advantage of being able to select the parameters of the mission – attack vector, speed and altitude. This results in an enormous area from which the attack can originate. In the time it takes for the bombers to cross the distance from first detection to being on their targets, the interceptor must be able to start, take off, climb to altitude, maneuver for attack and then attack the bomber.  A dedicated interceptor aircraft sacrifices the capabilities of the air superiority fighter and multirole fighter (i.e., countering enemy fighter aircraft in air combat manoeuvring), by tuning their performance for either fast climbs and/or high speeds. The result is that interceptors often look very impressive on paper, typically outrunning, outclimbing and outgunning slower fighter designs. However, pure interceptors fare poorly in fighter-to-fighter combat against the same "less capable" designs due to limited maneuverability especially at low altitudes.

Point defense interceptors.

In the spectrum of various interceptors, one design approach especially shows sacrifices necessary to achieve decisive benefit in a chosen aspect of performance. A "point defense interceptor" is of a lightweight design, intended to spend most of its time on the ground located at the defended target, and able to launch on demand, climb to altitude, manoeuvre and then attack the bomber in a very short time, before the bomber can deploy its weapons.  At the end of Second World War, the "Luftwaffe"s most critical requirement was for interceptors as the Commonwealth and American air forces pounded German targets night and day. As the bombing effort grew, notably in early 1944, the Luftwaffe introduced a rocket-powered design, the Messerschmitt Me 163 "Komet", in the very-short-range interceptor role. The engine allowed about 7 minutes of powered flight, but offered such tremendous performance that they could fly right by the defending fighters. The Me 163 required an airbase, however, which were soon under constant attack. Following the Emergency Fighter Program, the Germans developed even odder designs, such as the Bachem Ba 349 "Natter", which launched vertically and thus eliminated the need for an airbase. In general all these initial German designs proved difficult to operate, often becoming death traps for their pilots, and had little effect on the bombing raids. Rocket-boosted variants of both of Germany's jet fighters; the Me 262 in its "C" subtype series, all nicknamed "home protector" ("Heimatschützer", in four differing formats) and the planned He 162E subtype, using one of the same BMW 003R turbojet/rocket "mixed-power" engine as the Me 262C-2b "Heimatschützer II", but were never produced in quantity.  In the initial stage of Cold War, bombers were expected to attack flying higher and faster, even at transonic speeds. Initial transonic and supersonic fighters had modest internal fuel tanks in their slim fuselages, but a very high fuel consumption. This led fighter prototypes emphasizing acceleration and operational ceiling, with a sacrifice on the loiter time, essentially limiting them to point defense role. Such were the mixed jet/rocket power Republic XF-91 or Saunders Roe SR.53. The Soviet and Western trials with zero-length launch were also related. None of these found practical use. Designs that depended solely on jet engines achieved more success with the F-104 Starfighter (initial A version) and the English Electric Lightning.  The role of manned point defense designs was reassigned to unmanned interceptors—surface-to-air missiles (SAMs)—which first reached an adequate level in 1954–1957. SAM advancements ended the concept of massed high-altitude bomber operations, in favor of penetrators (and later cruise missiles) flying a combination of techniques colloquially known as "flying below the radar". By flying terrain masking low-altitude nap-of-the-earth flight profiles the effective range, and therefore reaction time, of ground-based radar was limited to at best the radar horizon. In the case of ground radar systems this can be countered by placing radar systems on mountain tops to extend the radar horizon, or through placing high performance radars in interceptors or in AWACs aircraft used to direct point defense interceptors.

Area defense.

As capabilities continued to improve – especially through the widespread introduction of the jet engine and the adoption of high speed, low level flight profiles, the time available between detection and interception dropped. Most advanced point defence interceptors combined with long-range radars were struggling to keep the reaction time down enough to be effective. Fixed times, like the time needed for the pilot to climb into the cockpit, became an increasing portion of the overall mission time, there were few ways to reduce this. During the Cold War in times of heightened tensions, quick reaction alert (QRA) aircraft were kept piloted, fully fuelled and armed, with the engines running at idle on the runway ready to take off. The aircraft being kept topped up with fuel via hoses from underground fuel tanks. If a possible intruder was identified, the aircraft would be ready to take off as soon as the external fuel lines were detached. However, keeping QRA aircraft at this state of readiness was physically and mentally draining to the pilots and was expensive in terms of fuel.  As an alternative, longer-range designs with extended loiter times were considered. These "area defense interceptors" or "area defense fighters" were in general larger designs intended to stay on lengthy patrol and protect a much larger area from attack, depending on greater detection capabilities, both in the aircraft themselves and operating with AWACS, rather than high speed to reach targets. The exemplar of this concept was the Tupolev Tu-28. The later Panavia Tornado ADV was able to achieve long range in a smaller airframe through the use of more efficient engines. Rather than focusing on acceleration and climb rate, the design emphasis is on range and missile carrying capacity, which together translate into combat endurance, look-down/shoot-down radars good enough to detect and track fast moving interdictors against ground clutter, and the capability to provide guidance to air-to-air missiles (AAM) against these targets. High speed and acceleration was put into long-range and medium-range AAMs, and agility into short range dog fighting AAMs, rather than into the aircraft themselves. They were first to introduce all-weather avionics, assuring successful operations during night, rain, snow, or fog.  Countries that were strategically dependent on surface fleet, most notably US and UK, maintained also "fleet defense fighters", such as the F-14 Tomcat.

Development.

Soviet Union and Russia.

During the Cold War, an entire military service, not just an arm of the pre-existing air force, was designated for deployment of interceptors. The aircraft of the Soviet Air Defence Forces (PVO-S) differed from those of the Soviet Air Forces (VVS) in that they were by no means small or crudely simple, but huge and refined with large, sophisticated radars; they could not take off from grass, only concrete runways; they could not be disassembled and shipped back to a maintenance center in a boxcar. Similarly, their pilots were given less training in combat maneuvers, and more in radio-directed pursuit.  The Soviets' main interceptor was initially the Su-9, which was followed by the Su-15 and the MiG-25 "Foxbat". The auxiliary Tu-28, an area range interceptor, was notably the heaviest fighter aircraft ever to see service in the world. The latest and most advanced interceptor aircraft in the Soviet (now Russian) inventory is the MiG-31 "Foxhound". Improving on some of the flaws on the proceeding MiG-25, the MiG-31 has better low altitude and low speed performance, in addition to carrying an internal cannon.  Russia, despite merging the PVO into the VVS, still plans to maintain its dedicated MiG-31 interceptor fleet.

United States.

In 1937, USAAC lieutenants Gordon P. Saville and Benjamin S. Kelsey devised a pair of proposals for interceptor aircraft, the first such designation in the US. One proposal was for a single-engined fighter, the other for a twin-engine. Both were required to reach an altitude of in six minutes as a defense against bomber attack. Kelsey said later that he used the "interceptor" designation to sidestep a hard USAAC policy restricting fighters to 500 lbs of armament. He wished for at least of armament so that American fighters could dominate their battles against all opponents, fighters included. The two aircraft resulting from these proposals were the single-engine Bell P-39 Airacobra and the twin-engine Lockheed P-38 Lightning. Both aircraft were successful during World War II in standard fighter roles, not specifically assigned to point defense against bombers.  From 1946 to 1980 the United States maintained a dedicated Aerospace Defense Command, consisting primarily of dedicated interceptors. Many post-war designs were of limited performance, including designs like the F-86D and F-89 Scorpion. In the late 1940s ADC started a project to build a much more advanced interceptor under the 1954 interceptor effort, which eventually delivered the F-106 Delta Dart after a lengthy development process. Further replacements were studied, notably the NR-349 proposal during the 1960s, but came to nothing as the USSR strengthened their strategic force with ICBMs. Hence, the F-106 ended up serving as the primary USAF interceptor into the 1980s.  As the F-106 was retired, intercept missions were assigned to the contemporary F-15 and F-16 fighters, among their other roles. The F-16, however, was originally designed for air superiority while evolving into a versatile multirole fighter. The F-15, with its Mach 2.5 maximum speed enabling it to intercept the fastest enemy aircraft (namely the MiG-25 Foxbat), is also not a pure interceptor as it has exceptional agility for dogfighting based upon the lessons learned from Vietnam; the F-15E Strike Eagle variant adds air interdiction while retaining the interception and air-to-air combat of other F-15s. Presently, the F-22 is the USA's latest combat aircraft that serves in part as an interceptor due to its supercruise capabilities, however it was designed primarily as a stealth air superiority fighter.  In the 1950s, the United States Navy led an unsuccessful F6D Missileer project. Later it launched the development of a large F-111B fleet air defense fighter, but this project was cancelled too. Finally, the role was assigned to the F-14 Tomcat, carrying AIM-54 Phoenix missiles. Like the USAF's F-15, the USN's F-14 was also designed primarily as an air superiority (fighter-to-fighter combat) and F-14s served the interceptor role until it received upgrades in the 1990s for ground attack. Both the fighter and the Phoenix missile were retired in 2006.

United Kingdom.

The British Royal Air Force operated a supersonic day fighter, the English Electric Lightning, alongside the Gloster Javelin in the subsonic night/all-weather role. Efforts to replace the Javelin with a supersonic design under Operational Requirement F.155 came to naught. The UK operated its own, highly adapted version of the McDonnell Douglas F-4 Phantom as its primary interceptor from the mid-1970s, with the air defence variant (ADV) of the Panavia Tornado being introduced in the 1980s. The Tornado was eventually replaced with a multirole design, the Eurofighter Typhoon.

China.

The Shenyang J-8 (Chinese: 歼-8; NATO reporting name: Finback) is a high-speed, high-altitude Chinese-built single-seat interceptor. Initially designed in the early 1960s to counter US-built B-58 Hustler bombers, F-105 Thunderchief fighter-bombers and Lockheed U-2 spy planes, it still retains the ability to'sprint' at Mach 2-plus speeds and later versions can carry medium-range PL-12/SD-10 MRAAM missiles for interception purposes. The PLAAF/PLANAF currently still operates approximately 300 or so J-8s of various configurations.

Other countries.

Several other countries also introduced interceptor designs, although in the 1950s–1960s several planned interceptors never came to fruition, with the expectation that missiles would replace bombers.  The Argentine FMA I.Ae. 37 was a prototype jet fighter developed during the 1950s. It never flew and was cancelled in 1960.  The Canadian subsonic Avro Canada CF-100 Canuck served in numbers through 1950s. Its supersonic replacement, the CF-105 Arrow ("Avro Arrow"), was controversially cancelled in 1959.  The Swedish Saab 35 Draken was specifically designed for intercepting aircraft passing Swedish airspace at high altitudes in the event of a war between the Soviet Union and NATO. With the advent of low flying cruise-missiles and high-altitude AA-missiles the flight profile was changed, but regained the interceptor profile with the final version J 35J.

An interceptor aircraft, or simply interceptor, is a type of fighter aircraft designed specifically for the defensive interception role against an attacking enemy aircraft, particularly bombers and reconnaissance aircraft. There are two general classes of interceptor: relatively lightweight aircraft built for high performance over short range, and heavier aircraft designed to fly at night or in adverse weather and operate over longer ranges.

拦截机(Interceptor)系一种特别强调以飞行速度和爬升率来拦截敌方轰炸机与侦察机等高空机种的军用飞机,通常被视为战斗机的一个类别。拦截机在第二次世界大战前后受到许多国家的重视,随着1960年代弹道导弹的成熟,战略轰炸机的重要性下降;加上战斗机逐渐拥有超音速巡航,拦截机的功用已由一般的防空导弹或多用途战斗机取代,目前很少有国家还在继续研发专门的拦截机。


History.

Rope-drawn transport dates back to 250 BC as evidenced by illustrations of aerial ropeway transportation systems in South China.

Early aerial tramways.

The first recorded mechanical ropeway was by Venetian Fausto Veranzio who designed a bi-cable passenger ropeway in 1616. The industry generally considers Dutchman Adam Wybe to have built the first operational system in 1644. The technology, which was further developed by the people living in the Alpine regions of Europe, progressed and expanded with the advent of wire rope and electric drive.  The first use of wire rope for aerial tramways is disputed. American inventor Peter Cooper is one early claimant, constructing an aerial tramway using wire rope in Baltimore 1832, to move landfill materials. Though there is only partial evidence for the claimed 1832 tramway, Cooper was involved in many of such tramways built in the 1850s, and in 1853 he built a two-mile-long tramway to transport iron ore to his blast furnaces at Ringwood, New Jersey.  World War I motivated extensive use of military tramways for warfare between Italy and Austria.  During the industrial revolution, new forms of cable-hauled transportation systems were created including the use of steel cable to allow for greater load support and larger systems. Aerial tramways were first used for commercial passenger haulage in the 1900s.

The first cable railways.

The earliest form of cable railway was the gravity incline, which in its simplest form consists of two parallel tracks laid on a steep gradient, with a single rope wound around a winding drum and connecting the trains of wagons on the tracks. Loaded wagons at the top of the incline are lowered down, their weight hauling empty wagons from the bottom. The winding drum has a brake to control the rate of travel of the wagons. The first use of a gravity incline isn't recorded, but the Llandegai Tramway at Bangor in North Wales was opened in 1798, and is one of the earliest examples using iron rails.  The first cable-hauled street railway was the London and Blackwall Railway, built in 1840, which used fibre to grip the haulage rope. This caused a series of technical and safety issues, which led to the adoption of steam locomotives by 1848.  The first Funicular railway was opened in Lyon in 1862.  The Westside and Yonkers Patent Railway Company developed a cable-hauled elevated railway. This 31⁄2 mile long line was proposed in 1866 and opened in 1868. It operated as a cable railway until 1871 when it was converted to use steam locomotives.  The next development of the cable car came in California. Andrew Hallidie, a Scottish emigre, gave San Francisco the first effective and commercially successful route, using steel cables, opening the Clay Street Hill Railroad on August 2, 1873. Hallidie was a manufacturer of steel cables. The system featured a human-operated grip, which was able to start and stop the car safely. The rope that was used allowed the multiple, independent cars to run on one line, and soon Hallidie's concept was extended to multiple lines in San Francisco.  The first cable railway outside the United Kingdom and the United States was the Roslyn Tramway, which opened in 1881, in Dunedin, New Zealand. America remained the country that made the greatest use of cable railways; by 1890 more than 500 miles of cable-hauled track had been laid, carrying over 1,000,000 passengers per year. However, in 1890, electric tramways exceeded the cable hauled tramways in mileage, efficiency and speed.

Early ski lifts.

The ski lift was developed by James Curran in 1936. The co-owner of the Union Pacific Railroad, William Averell Harriman owned America's first ski resort, Sun Valley, Idaho. He asked his design office to tackle the problem of lifting skiers to the top of the resort. Curran, a Union Pacific bridge designer, adapted a cable hoist he had designed for loading bananas in Honduras to create the first ski lift.

More recent developments.

More recent developments are being classified under the type of track that their design is based upon. After the success of this operation, several other projects were initiated in New Zealand and Chicago. The social climate around pollution is allowing for a shift from cars back to the utilization of cable transport due to their advantages. However, for many years they were a niche form of transportation used primarily in difficult-to-operate conditions for cars (such as on ski slopes as lifts). Now that cable transport projects (CTP) are on the increase, the social effects are beginning to become more significant. In 2018 the highest 3S cablecar has been inaugurated in Zermatt, Switzerland after more than two years of construction. This cablecar is also called the "Matterhorn Glacier ride"and it allows passengers to reach the top of the Klein Matterhorn mountain. (3383m)

Social effects.

Comparison with other transport types.

When compared to trains and cars, the volume of people to transport over time and the start-upcost of the project must be a consideration. In areas with extensive road networks, personal vehicles offer greater flexibility and range. Remote places like mountainous regions and ski slopes may be difficult to link with roads, making CTP a much easier approach. A CTP system may also need fewer invasive changes to the local environment.  The use of Cable Transport is not limited to such rural locations as skiing resorts; it can be used in urban development areas. Their uses in urban areas include funicular railways, gondola lifts, and aerial tramways.

Cable transport is a broad class of transport modes that have cables. They transport passengers and goods, often in vehicles called cable cars. The cable may be driven or passive, and items may be moved by pulling, sliding, sailing, or by drives within the object being moved on cableways. The use of pulleys and balancing of loads moving up and down are common elements of cable transport. They are often used in mountainous areas where cable haulage can overcome large differences in elevation.

空中缆车又称-{zh-hans:吊车; zh-tw:索道; zh-hk:索道}-、-{zh-hans:空中缆车; zh-tw:吊车; zh-hk:空中缆车}-、流笼(缆车又可以指缆索铁路),是交通工具的一种,通常在崎岖的山坡上运载乘客或货物上下山。索道是利用悬挂在半空中的钢索,承托及牵引客车或货车。除了车站外,一般在中途每隔一段距离建造承托钢索的支架。部分的索道采用吊挂在钢索之下的吊车;亦有索道是没有车厢的,乘客坐在开放在半空的吊椅。使用吊椅的索道在滑雪区最为常见。


History.

The history of aerial warfare began in ancient times, with the use of man-carrying kites in Ancient China. In the third century it progressed to balloon warfare.  Airplanes were put to use for war starting in 1911, initially for aerial reconnaissance, and then for aerial combat to shoot down the enemy reconnaissance planes. Aircraft continued to carry out these roles during World War I, where the use of planes and zeppelins for strategic bombing also emerged.  During World War II, the use of strategic bombing increased, while airborne forces, missiles, and early precision-guided munitions were introduced.  Ballistic missiles became of key importance during the Cold War, were armed with nuclear warheads, and were stockpiled by the United States and the Soviet Union to deter each other from using them. The first military satellites were used for reconnaissance in the 1950s, and their use has progressed to worldwide communication and information systems that support globally distributed military users with intelligence from orbit.

Aerial reconnaissance.

Aerial reconnaissance is reconnaissance for a military or strategic purpose that is conducted using reconnaissance aircraft. This role can fulfil a variety of requirements, including the collection of imagery intelligence, observation of enemy maneuvers and artillery spotting.

Air combat manoeuvring.

Air combat manoeuvring (also known as ACM or dogfighting) is the tactical art of moving, turning and situating a fighter aircraft in order to attain a position from which an attack can be made on another aircraft. It relies on offensive and defensive basic fighter manoeuvring (BFM) to gain an advantage over an aerial opponent.

Airborne forces.

Airborne forces are military units, usually light infantry, set up to be moved by aircraft and "dropped" into battle, typically by parachute. Thus, they can be placed behind enemy lines, and have the capability to deploy almost anywhere with little warning. The formations are limited only by the number and size of their aircraft, so given enough capacity a huge force can appear "out of nowhere" in minutes, an action referred to as "vertical envelopment".  Conversely, airborne forces typically lack the supplies and equipment for prolonged combat operations, and are therefore more suited for airhead operations than for long-term occupation; furthermore, parachute operations are particularly sensitive to adverse weather conditions. Advances in helicopter technology since World War II have brought increased flexibility to the scope of airborne operations, and air assaults have largely replaced large-scale parachute operations, and (almost) completely replaced combat glider operations.

Airstrike.

An airstrike or "air strike" is an offensive operation carried out by attack aircraft. Air strikes are commonly delivered from aircraft such as fighters, bombers, ground attack aircraft, and attack helicopters. The official definition includes all sorts of targets, including enemy air targets, but in popular use the term is usually narrowed to a tactical (small-scale) attack on a ground or naval objective. Weapons used in an airstrike can range from machine gun bullets and missiles to various types of bombs. It is also commonly referred to as an "air raid".  In close air support, air strikes are usually controlled by trained observers for coordination with friendly ground troops in a manner derived from artillery tactics.

Strategic bombing.

Strategic bombing is a military strategy used in a total war with the goal of defeating the enemy by destroying their morale or their economic ability to produce and transport materiel to the theatres of military operations, or both. It is a systematically organized and executed attack from the air which can utilize strategic bombers, long- or medium-range missiles, or nuclear-armed fighter-bomber aircraft to attack targets deemed vital to the enemy's war-making capability.

Anti-aircraft warfare.

Anti-aircraft warfare or "counter-air defence" is defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground-and air-based weapon systems, associated sensor systems, command and control arrangements and passive measures (e.g. barrage balloons). It may be used to protect naval, ground, and air forces in any location. However, for most countries the main effort has tended to be 'homeland defence'. NATO refers to airborne air defence as "counter-air" and naval air defence as "anti-aircraft warfare". Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting any projectile in flight.

Missiles.

In modern usage, a missile is a self-propelled precision-guided munition system, as opposed to an unguided self-propelled munition, referred to as a rocket (although these too can also be guided). Missiles have four system components: targeting and/or missile guidance, flight system, engine, and warhead. Missiles come in types adapted for different purposes: surface-to-surface and air-to-surface missiles (ballistic, cruise, anti-ship, anti-tank, etc.), surface-to-air missiles (and anti-ballistic), air-to-air missiles, and anti-satellite weapons. All known existing missiles are designed to be propelled during powered flight by chemical reactions inside a rocket engine, jet engine, or other type of engine. Non-self-propelled airborne explosive devices are generally referred to as shells and usually have a shorter range than missiles.  In ordinary British-English usage predating guided weapons, a missile is "any thrown object", such as objects thrown at players by rowdy spectators at a sporting event.

UAVs.

The advent of the unmanned aerial vehicle has dramatically revolutionized aerial warfare with multiple nations developing and/or purchasing UAV fleets. Several benchmarks have already occurred, including a UAV-fighter jet dogfight, probes of adversary air defense with UAVs, replacement of an operational flight wing's aircraft with UAVs, control of UAVs qualifying the operator for 'combat' status, UAV-control from the other side of the world, jamming and/or data-hijacking of UAVs in flight, as well as proposals to transfer fire authority to AI aboard a UAV. UAVs have quickly evolved from surveillance to combat roles.  The growing capability of UAVs has thrown into question the survivability and capability of manned fighter jets.

Aerial warfare is the battlespace use of military aircraft and other flying machines in warfare. Aerial warfare includes bombers attacking enemy installations or a concentration of enemy troops or strategic targets; fighter aircraft battling for control of airspace; attack aircraft engaging in close air support against ground targets; naval aviation flying against sea and nearby land targets; gliders, helicopters and other aircraft to carry airborne forces such as paratroopers; aerial refueling tankers to extend operation time or range; and military transport aircraft to move cargo and personnel. Historically, military aircraft have included lighter-than-air balloons carrying artillery observers; lighter-than-air airships for bombing cities; various sorts of reconnaissance, surveillance and early warning aircraft carrying observers, cameras and radar equipment; torpedo bombers to attack enemy shipping; and military air-sea rescue aircraft for saving downed airmen. Modern aerial warfare includes missiles and unmanned aerial vehicles. Surface forces are likely to respond to enemy air activity with anti-aircraft warfare.

空战是利用军用飞机和其它飞行器进行的航空作战。空战包含了利用轰炸机攻击敌方部队(战术轰炸)或著敌方的民生生产单位(战略轰炸);战斗机之间战斗争夺制空权;攻击机执行空中密接支援攻击地面目标;海军航空战力;滑翔机、直升机运载空中单位例如伞兵;空中加油;以及运输货物和人员。现代空战包含了导弹以及无人机。地面军力可能会以对空武器回应敌方空中活动。


History of the castle.

The town was built in Prussia around the fortress Ordensburg Marienburg, which was founded in 1274 on the east bank of the river Nogat by the Teutonic Knights. Both the castle and the town (named Marienburg in German and Malborg or Malbork in Polish) were named for their patron saint, the Virgin Mary. This fortified castle became the seat of the Teutonic Order and Europe's largest Gothic fortress. During the Thirteen Years' War, the castle of Marienburg was pawned by the Teutonic Order to their imperial soldiers from Bohemia. They sold the castle in 1457 to King Casimir IV of Poland in lieu of indemnities. From 1457 to 1772 the castle was one of Poland's royal residences. Polish Kings often stayed in the castle, especially when travelling to the nearby city of Gdańsk. Also astronomer Nicolaus Copernicus visited the castle. From 1568 the castle also housed the Polish Admiralty ("Komisja Morska") and in 1584 one of the Polish Royal Mints was established here. The largest arsenal of the Polish-Lithuanian Commonwealth was located in the castle.  Under continuous construction for nearly 230 years, the castle complex is actually three castles combined in one. A classic example of a medieval fortress, it is the world’s largest brick castle and one of the most impressive of its kind in Europe. The castle was in the process of being restored by the Germans when World War II broke out. During the war, the castle was over 50% destroyed. Restoration has been ongoing since the war. The castle and its museum are listed as one of UNESCO's World Heritage Sites.

History of the town.

Middle Ages.

The town of Marienburg grew in the vicinity of the castle. The river Nogat and flat terrain allowed easy access for barges a hundred kilometers from the sea. During Prussia's government by the Teutonic Knights, the Order collected tolls on river traffic and imposed a monopoly on the amber trade. The town later became a member of the Hanseatic League, and many Hanseatic meetings were held there.  The Teutonic Order weakened greatly after the Battle of Grunwald against advancing Poles and Lithuanians. The town was burned by the Teutonic Knights in 1410 before the siege of the castle by Poles, however it remained under Teutonic control after the siege. In 1457, during the Thirteen Years' War, the castle was sold to Poland by Czech mercenaries of the Teutonic Knights, and the Teutonic Order transferred its seat to Königsberg (now Kaliningrad, Russia). The town of Marienburg, under Mayor Bartholomäus Blume and others, resisted the Poles for three further years. But when the Poles finally took control, Blume was hanged and quartered, and fourteen officers and three remaining Teutonic knights were thrown into dungeons, where they met a miserable end. A monument to Blume was erected in 1864.  The town became capital of the Malbork Voivodeship in the Polish province of Royal Prussia after the Second Peace of Thorn (1466), however still mainly settled by Germans.

Modern period.

Within Poland, Malbork flourished thanks to the Polish grain and wood trade and craft development. New suburbs were created due to lack of space within the defensive walls. In the 17th century, Swedish invasions took place. During the Great Northern War in 1710, half of the population died of a cholera epidemic. After the wars, new inhabitants, including immigrants from Scotland, settled in the town, mainly in the suburbs. In 1740 Malbork ceased to be a fortress. It was annexed by the Kingdom of Prussia in the First Partition of Poland in 1772 and became part of the newly established Province of West Prussia the following year, which became part of the newly founded German Empire in 1871. Prussians liquidated the municipal government and replaced it with new Prussian-appointed administration. In 1807, during the Napoleonic Wars, the French entered the town, and in 1812 the Grande Armée marched through the town heading for Russia. Napoleon has visited the town in those years.  There were no World War I fights, however, the town felt the war's negative effects: the influx of refugees, inflation, unemployment, and food supply shortages.  Under the terms of the Treaty of Versailles after World War I, the inhabitants were asked in a plebiscite on July 11, 1920 whether they wanted to remain in Germany or join newly re-established Poland. In the town of Marienburg, 9,641 votes were cast for Germany, 165 votes for Poland. As a result, Marienburg was included in the Regierungsbezirk Marienwerder within the German Province of East Prussia. During the Weimar era, Marienburg was located at the tripoint between Poland, Germany and the Free City of Danzig.  The town was hit by an economic crisis following the end of World War I. After a brief recovery in the mid-1920s, the Great Depression was particularly severe in East Prussia. In January 1933, Hitler and the Nazi Party came to power and immediately began eliminating political opponents, so that in the last semi-free elections of March 1933, 54% of Marienburg's votes went to the Nazis. After the German invasion of Poland in September 1939, leaders of the Polish minority were arrested and sent to concentration camps.

World War II.

During World War II a Focke-Wulf aircraft factory was set up at the airfield to the east of Marienburg. It was bombed twice by the USAAF in 1943 and 1944. Today the airfield belongs to the 22nd Air Base of the Polish Air Force.  During the war, the Germans established the Stalag XX-B prisoner of war camp, among the prisoners of which were the British, French, Poles, Belgians and Yugoslavs. Also a forced labour camp was established.  Near the end of World War II, the city was declared a festung and most of the civilian population fled or were evacuated, with some 4,000 people opting to remain. In early 1945, Marienburg was the scene of fierce battles by the Nazis against the Red Army and was almost completely destroyed. The battle lasted until March 9, 1945. Following the town's military capture by the Red Army, the remaining civilian population disappeared; 1,840 people remain missing. In June 1945, the town was turned over to Polish authorities who had arrived in the town in April and renamed city with its present Polish name, Malbork. The German population of Marienburg that had not fled was expelled. Historic relics of the German-speaking population were destroyed.  Half a century later, in 1996, 178 corpses were found in a mass grave in Malbork; another 123 were found in 2005. In October 2008, during excavations for the foundation of a new hotel in Malbork, a mass grave was found containing the remains of 2,116 people, a majority of whom were female. All the dead were said to have been German residents of pre-1945 Marienburg, but they could not be individually identified, nor could the cause of their deaths be definitely established. A Polish investigation concluded that the bodies, along with the remains of some dead animals, may have been buried to prevent the spread of typhus, which was extant in the turmoil at the end of World War II. On August 14, 2009, all the dead people’s remains were buried in a German military cemetery to the west of the town at Stare Czarnowo in Polish Pomerania, not far from the present-day German border.  In Malbork one can also find a Commonwealth War Graves Commission cemetery with 240 graves, mostly of POWs who died in the area during both wars, especially in the World War II Stalag XX-B camp.

Post-war period.

After World War II, the town was gradually repopulated by Poles, many expelled from Polish areas annexed by the Soviet Union. In February 1946, the population of the town reached 10,017 people, then by 1965 grew further to 28,292 and by 1994 to 40,347.  In April 1945 the malt house resumed work, in May a Polish post office was established and the first post-war Polish services were held in the St. John church, in September Polish schools were opened. In the following years, most of the war damage was removed, and in 1947 the railway bridge on the Nogat was rebuilt, after it was destroyed by the Germans in March 1945. A new road bridge was built in 1949. In 1946 a sugar factory was established.  Also following the war, the Old Town in Malbork was not rebuilt; instead the bricks from its ruins were used to rebuild the oldest sections of Warsaw and Gdańsk. As a result, with the exception of the Old Town Hall, two city gates and St. John's church, no pre-World War II buildings remain in the Old Town area. In place of the old town, a housing estate was built in the 1960s.  In 1962, a pasta factory was established in Malbork, which soon became one of the largest pasta factories in Poland.

Sports.

The towns football club is Pomezania Malbork, who currently play in the sixth tier.

International relations.

Malbork is twinned with:

Malbork (;, ; ) is a town in northern Poland, within the historical region of Pomerania. Situated in the Pomeranian Voivodeship since 1999, it was previously assigned to Elbląg Voivodeship (1975–1998). It is the capital of Malbork County and the population was estimated at 38,723, as of 2018.

马尔堡(波兰语:,德语:Marienburg,马林堡)是波兰北部的一个城镇,是波美拉尼亚省马尔堡县的首府,人口40,135。马林堡在13世纪由条顿骑士团建立,以马尔堡城堡闻名。原先是德国西普鲁士省内一个城镇,1945年被割让给波兰,改名马尔堡,原有德意志居民被驱逐。德意志地区另有两个马尔堡Marburg,一个位于黑森,一个位于今斯洛文尼亚(原奥地利的施里蒂亚公国),后者在斯洛文尼亚语叫马里博尔。


History.

The world's earliest known dockyards were built in the Harappan port city of Lothal circa 2600 BC in Gujarat, India. Lothal's dockyards connected to an ancient course of the Sabarmati river on the trade route between Harappan cities in Sindh and the peninsula of Saurashtra when the surrounding Kutch desert was a part of the Arabian Sea.  Lothal engineers accorded high priority to the creation of a dockyard and a warehouse to serve the purposes of naval trade. The dock was built on the eastern flank of the town, and is regarded by archaeologists as an engineering feat of the highest order. It was located away from the main current of the river to avoid silting, but provided access to ships in high tide as well.  The name of the ancient Greek city of Naupactus means "shipyard" (combination of the Greek words ναύς "naus" ship, boat and πήγνυμι "pêgnumi", "pegnymi" builder, fixer). Naupactus' reputation in this field extends to the time of legend, where it is depicted as the place where the Heraclidae built a fleet to invade the Peloponnesus.  In the Spanish city of Barcelona, the Drassanes shipyards were active from at least the mid-13th century until the 18th century, although it at times served as a barracks for troops as well as an arsenal. During its time of operation it was continuously changed, rebuilt and modified, but two original towers and part of the original eight construction naves remain today. It is currently a maritime museum.  Ships were the first items to be manufactured in a factory, several hundred years before the Industrial Revolution, in the Venice Arsenal, Venice, Italy. The Arsenal apparently mass-produced nearly one ship every day using pre-manufactured parts, and assembly lines and, at its height, employed 16,000 people.

A shipyard (also called a dockyard) is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance and basing activities than shipyards, which are sometimes associated more with initial construction. The terms are routinely used interchangeably, in part because the evolution of dockyards and shipyards has often caused them to change or merge roles.

造船厂(英语:Shipyards, dockyards),是制造和维修船只的场所。造船厂负责的范围可能为游艇、军舰、货轮、超大游轮或者其他船只。因为造船厂的设施不同和更新,所以其职能也通常进行变化。世界上最大的造船厂分别位于美国、澳大利亚、日本、中国、德国、土耳其、台湾、韩国、波兰和克罗地亚等国。在欧洲的造船厂分布比较零散,而在亚洲的造船厂和造船工业比较集中和大型。


Nomenclature.

In English, the round in which only eight competitors remain is generally called (with or without hyphenation) the "quarter-final" round; this is followed by the "semi-final" round, in which only four are left, the two winners of which then meet in the final or "championship round".  The round before the quarterfinals has multiple designations. Often it is called the "round of sixteen", "last sixteen", or (in South Asia) "pre quarter-finals". In many other languages the term for these eight matches translates to "eighth-final" (e.g., in these seven European languages: "huitième de finale" in French, "octavos de final" in Spanish, "Achtelfinale" in German, "ottavi di finale" in Italian, "osmifinále" in Czech, "osemfinále" in Slovak, and "osmina finala" in Serbian), though this term is rare in English itself.  The round before the round of sixteen is sometimes called "round of thirty-two" in English. Terms for this in other languages generally translate as "sixteenth final".  Earlier rounds are typically numbered counting forwards from the first round, or by the number of remaining competitors. If some competitors get a bye, the round at which they enter may be named the "first round", with the earlier matches called a "preliminary round", "qualifying round", or the "play-in games"".  Examples of the diverse names given to concurrent rounds in various select disciplines:  Notes:

Example.

The final three rounds of the 2014 Australian Open – Women's Singles knock-out tournament:

Classification.

When matches are held to determine places or prizes lower than first and second (the loser of the final-round match gaining the latter position), these typically include a match between the losers of the semifinal matches called third place playoffs, the winner therein placing third and the loser fourth. Many Olympic single-elimination tournaments feature the bronze medal match if they do not award bronze medals to both losing semifinalists. The FIFA World Cup has long featured the third place match (since 1934), though the UEFA Euro has not held one since the 1980 edition.  Sometimes, contests are also held among the losers of the quarterfinal matches to determine fifth to eighth places – this is most commonly encountered in the Olympic Games, with the exception of boxing, where both fighters are deemed to be third place. In one scenario, two "consolation semifinal" matches may be conducted, with the winners of these then facing off to determine fifth and sixth places and the losers playing for seventh and eighth; those are used often in qualifying tournaments where only the top five teams advance to the next round; or some method of ranking the four quarterfinal losers might be employed, in which case only one round of additional matches would be held among them, the two highest-ranked therein then playing for fifth and sixth places and the two lowest for seventh and eighth.  The number of distinct ways of arranging a single-elimination tournament (as an abstract structure, prior to seeding the players into the tournament) is given by the Wedderburn–Etherington numbers. Thus, for instance, there are three different arrangements for five players: However, the number of arrangements grows quickly for larger numbers of players and not all of them are commonly used.

Seeding.

Opponents may be allocated randomly (such as in the FA Cup); however, since the "luck of the draw" may result in the highest-rated competitors being scheduled to face each other early in the competition, "seeding" is often used to prevent this. Brackets are set up so that the top two seeds could not possibly meet until the final round (should both advance that far), none of the top four can meet prior to the semifinals, and so on. If no seeding is used, the tournament is called a random knockout tournament.  One version of seeding is where brackets are set up so that the quarterfinal pairings (barring any upsets) would be the 1 seed vs. the 8 seed, 2 vs. 7, 3 vs. 6 and 4 vs. 5; however, this is not the procedure that is followed in most tennis tournaments, where the 1 and 2 seeds are placed in separate brackets, but then the 3 and 4 seeds are assigned to their brackets randomly, and so too are seeds 5 through 8, and so on. This may result in some brackets consisting of stronger players than other brackets, and since only the top 32 players are seeded at all in Tennis Grand Slam tournaments, it is conceivable that the 33rd-best player in a 128-player field could end up playing the top seed in the first round. A good example of this occurring was when World No. 33 Florian Mayer was drawn against (and eventually defeated by) then-World No. 1 Novak Djokovic in the first round of the 2013 Wimbledon Championships, in what was also a rematch of a quarterfinal from the previous year. While this may seem unfair to a casual observer, rankings of tennis players are generated by computers, and players tend to change ranking positions very gradually, so that a more equitable method of determining the pairings might result in many of the same head-to-head matchups being repeated over and over again in successive tournaments.  Sometimes the remaining competitors in a single-elimination tournament will be "re-seeded" so that the highest surviving seed is made to play the lowest surviving seed in the next round, the second-highest plays the second-lowest, etc. This may be done after each round, or only at selected intervals. In American team sports, for example, the NFL and WNBA employ this tactic, but MLS, NHL and the NBA do not (and neither does the NCAA college basketball tournament). MLB does not have enough teams (10) in its playoff tournament where re-seeding would make a large difference in the matchups; only the WNBA's at the minimum, which is at least two from each conference (or league in MLB) for a total of 8. The NBA's format calls for the winner of the first-round series between the first and eighth seeds (within each of the two conferences the league has) to face the winner of the first-round series between the fourth and fifth seeds in the next round, even if one or more of the top three seeds had been upset in their first-round series; critics have claimed that this gives a team fighting for the fifth and sixth seeding positions near the end of the regular season an incentive to tank (deliberately lose) games, so as to finish sixth and thus avoid a possible matchup with the top seed until one round later. MLS's format is identical, except that the top-seed gets a conference-quarterfinal bye to play 4th-5th seed winner.  In some situations, a seeding restriction may be implemented; from 1975 until 1989 in the NFL, and from 1994 until 2011 in MLB there was a rule where at the conference or league semifinal, should the top seed and last seed (wild card) be from the same division, they could not play each other; in that case, the top seed plays the worst division champion; the second-best division champion plays the wild card team. This is due to the scheduling employed for the regular season, in which a team faces any given divisional opponent more often than any given non-divisional opponent – the tournament favors matchups that took place fewer times in the regular season (or did not take place, in some cases).  In international fencing competitions, it is common to have a group stage. Participants are divided in groups of 6–7 fencers who play a round-robin tournament, and a ranking is calculated from the consolidated group results. Single elimination is seeded from this ranking.

Evaluation.

The single-elimination format enables a relatively large number of competitors to participate. There are no "dead" matches (perhaps excluding "classification" matches), and no matches where one competitor has more to play for than the other.  The format is less suited to games where draws are frequent. In chess, each fixture in a single-elimination tournament must be played over multiple matches, because draws are common, and because white has an advantage over black. In association football, games ending in a draw may be settled in extra time and eventually by a penalty shootout or by replaying the fixture.  Another perceived disadvantage is that most competitors are eliminated after relatively few games. Variations such as the double-elimination tournament allow competitors a single loss while remaining eligible for overall victory. However, losing one game requires the competitor to win more games in order to win the tournament.  In a random knockout tournament (single-elimination without any seeding), awarding the second place to the loser of the final is unjustified: any of the competitors knocked out by the tournament winner might have been the second strongest one, but they never got the chance to play against the losing finalist. In general, it is only fair to use a single-elimination tournament to determine first place. To fairly determine lower places requires some form of round-robin in which each player/team gets the opportunity to face every other player/team.  Also, if the competitors' performance is variable, that is, it depends on a small, varying factor in addition to the actual strength of the competitors, then not only will it become less likely that the strongest competitor actually wins the tournament, in addition the seeding done by the tournament organizers will play a major part in deciding the winner. As a random factor is always present in a real-world competition, this might easily cause accusations of unfairness.

Other tournament systems.

Variations of the single-elimination tournament include: Other common tournament types include:

A single-elimination, knockout, or sudden death tournament is a type of elimination tournament where the loser of each match-up is immediately eliminated from the tournament. Each winner will play another in the next round, until the final match-up, whose winner becomes the tournament champion. Each match-up may be a single match or several, for example two-legged ties in European football or best-of series in American pro sports. Defeated competitors may play no further part after losing, or may participate in "consolation" or "classification" matches against other losers to determine the lower final rankings; for example, a third place playoff between losing semi-finalists. In a shootout poker tournament, there are more than two players competing at each table, and sometimes more than one progressing to the next round. Some competitions are held with a pure single-elimination tournament system. Others have many phases, with the last being a single-elimination final stage, often called playoffs.

单败淘汰制是一种竞赛形式,每场比赛的负方将与竞赛的冠军或锦标绝缘,但不表示负方在出局后再没有比赛,部分竞赛的负方仍需为排名角逐“名次赛”或“遗材赛”。而足球运动所谓的「杯赛」,一般泛指采用单败淘汰来决定冠军的竞赛。


Membership.

History.

On 12 January 1960, the Treaty on the European Free Trade Association was initiated in the Golden Hall of the Stockholm City Hall. This established the progressive elimination of customs duties on industrial products, but did not affect agricultural or fisheries products.  The main difference between the early EEC and the EFTA was that the latter did not operate common external customs tariffs unlike the former: each EFTA member was free to establish its individual customs duties against, or its individual free trade agreements with, non-EFTA countries.  The founding members of the EFTA were: Austria, Denmark, Norway, Portugal, Sweden, Switzerland, and the United Kingdom. During the 1960s, these countries were often referred to as the "Outer Seven", as opposed to the Inner Six of the then European Economic Community (EEC).  Finland became an associate member in 1961 and a full member in 1986, and Iceland joined in 1970. The United Kingdom and Denmark joined the EEC in 1973 and hence ceased to be EFTA members. Portugal also left EFTA for the European Community in 1986. Liechtenstein joined the EFTA in 1991 (previously its interests had been represented by Switzerland). Austria, Sweden, and Finland joined the EU in 1995 and thus ceased to be EFTA members.  Twice, in 1973 and in 1995, the Norwegian government had tried to join the EU (still the EEC, in 1973) and by doing so, leave the EFTA. However, both the times, the membership of the EU was rejected in national referenda, keeping Norway in the EFTA. Iceland applied for EU membership in 2009 due to the 2008–2011 Icelandic financial crisis, but has since dropped its bid.

Other negotiations.

Between 1994 and 2011, EFTA memberships for Andorra, San Marino, Monaco, the Isle of Man, Turkey, Israel, Morocco, and other European Neighbourhood Policy partners were discussed.

Monaco, Andorra and San Marino.

In November 2012, after the Council of the European Union had called for an evaluation of the EU's relations with Monaco, Andorra and San Marino, which they described as "fragmented", the European Commission published a report outlining the options for their further integration into the EU. Unlike Liechtenstein, which is a member of the EEA via the EFTA and the Schengen Agreement, relations with these three states are based on a collection of agreements covering specific issues. The report examined four alternatives to the current situation: However, the Commission argued that the sectoral approach did not address the major issues and was still needlessly complicated, while EU membership was dismissed in the near future because "the EU institutions are currently not adapted to the accession of such small-sized countries". The remaining options, EEA membership and a FAA with the states, were found to be viable and were recommended by the Commission. In response, the Council requested that negotiations with the three microstates on further integration continue, and that a report be prepared by the end of 2013 detailing the implications of the two viable alternatives and recommendations on how to proceed.  As the EEA memberships are currently only open to the EFTA or EU members, the consent of the existing EFTA member states is required for the microstates to join the EEA without becoming members of the EU. In 2011, Jonas Gahr Støre, then Foreign Minister of Norway which is an EFTA member state, said that EFTA/EEA membership for the microstates was not the appropriate mechanism for their integration into the internal market due to their different requirements from those of large countries such as Norway, and suggested that a simplified association would be better suited for them. Espen Barth Eide, Støre's successor, responded to the Commission's report in late 2012 by questioning whether the microstates have sufficient administrative capabilities to meet the obligations of EEA membership. However, he stated that Norway was open to the possibility of EFTA membership for the microstates if they decide to submit an application, and that the country had not made a final decision on the matter. Pascal Schafhauser, the Counsellor of the Liechtenstein Mission to the EU, said that Liechtenstein, another EFTA member state, was willing to discuss EEA membership for the microstates provided their joining, did not impede the functioning of the organization. However, he suggested that the option direct membership in the EEA for the microstates, outside of both the EFTA and the EU, should be considered. On 18 November 2013, the EU Commission concluded that "the participation of the small-sized countries in the EEA is not judged to be a viable option at present due to the political and institutional reasons," and that, Association Agreements were a more feasible mechanism to integrate the microstates into the internal market.

Norway.

The Norwegian electorate had rejected treaties of accession to the EU in two referendums. At the time of the first referendum in 1972, their neighbour, Denmark joined. Since the second referendum in 1994, two other Nordic neighbours, Sweden and Finland, have joined the EU. The last two governments of Norway have not advanced the question, as they have both been coalition governments consisting of proponents and opponents of EU membership.

Switzerland.

Since Switzerland rejected the EEA membership in a referendum in 1992, more referendums on EU membership have been initiated, the last time being in 2001. These were all rejected. Switzerland has been in a customs union with fellow EFTA member state and neighbour Liechtenstein since 1924.

Iceland.

On 16 July 2009, the government of Iceland formally applied for the EU membership, but the negotiation process had been suspended since mid-2013, and in 2015 the foreign ministers wrote to withdraw its application.

Faroe Islands.

In mid-2005, representatives of the Faroe Islands raised the possibility of their territory joining the EFTA. According to Article 56 of the EFTA Convention, only states may become members of the EFTA. The Faroes are a constituent country of the Kingdom of Denmark, and not a sovereign state in their own right. Consequently, they considered the possibility that the "Kingdom of Denmark in respect of the Faroes" could join the EFTA, though the Danish Government has stated that this mechanism would not allow the Faroes to become a separate member of the EEA because Denmark was already a party to the EEA Agreement.  The Faroes already have an extensive bilateral free trade agreement with Iceland, known as the Hoyvík Agreement.

United Kingdom.

The United Kingdom was a co-founder of EFTA in 1960, but ceased to be a member upon joining the European Economic Community. The country held a referendum in 2016 on withdrawing from the EU (popularly referred to as "Brexit"), resulting in a 51.9% vote in favour of withdrawing. A 2013 research paper presented to the Parliament of the United Kingdom proposed a number of alternatives to EU membership which would continue to allow it access to the EU's internal market, including continuing EEA membership as an EFTA member state, or the Swiss model of a number of bilateral treaties covering the provisions of the single market.  In the first meeting since the Brexit vote, EFTA reacted by saying both that they were open to a UK return, and that Britain has many issues to work through. The president of Switzerland Johann Schneider-Ammann stated that its return would strengthen the association. However, in August 2016 the Norwegian Government expressed reservations. Norway's European affairs minister, Elisabeth Vik Aspaker, told the "Aftenposten" newspaper: "It’s not certain that it would be a good idea to let a big country into this organization. It would shift the balance, which is not necessarily in Norway’s interests."  In late 2016, the Scottish First Minister said that her priority was to keep the whole of the UK in the European single market but that taking Scotland alone into the EEA was an option being "looked at". However, other EFTA states have stated that only sovereign states are eligible for membership, so it could only join if it became independent from the UK, unless the solution scouted for the Faroes in 2005 were to be adopted (see above).  In early 2018, British MPs Antoinette Sandbach, Stephen Kinnock and Stephen Hammond all called for the UK to rejoin EFTA.

Organisation.

EFTA is governed by the EFTA Council and serviced by the EFTA Secretariat. In addition, in connection with the EEA Agreement of 1992, two other EFTA organisations were established, the EFTA Surveillance Authority and the EFTA Court.

Council.

The EFTA Council is the highest governing body of EFTA. The Council usually meets eight times a year at the ambassadorial level (heads of permanent delegations to EFTA) and twice a year at Ministerial level. In the Council meetings, the delegations consult with one another, negotiate and decide on policy issues regarding EFTA. Each Member State is represented and has one vote, though decisions are usually reached through consensus.  The Council discusses substantive matters, especially relating to the development of EFTA relations with third countries and the management of free trade agreements, and keeps under general review relations with the EU third-country policy and administration. It has a broad mandate to consider possible policies to promote the overall objectives of the Association and to facilitate the development of links with other states, unions of states or international organisations. The Council also manages relations between the EFTA States under the EFTA Convention. Questions relating to the EEA are dealt with by the Standing Committee in Brussels.

Secretariat.

The day-to-day running of the Secretariat is headed by the Secretary-General, Henri Gétaz, who is assisted by two Deputy Secretaries-General, one based in Geneva and the other in Brussels. The three posts are shared between the Member States. The division of the Secretariat reflects the division of EFTA's activities. The Secretariat employs approximately 100 staff members, of whom a third are based in Geneva and two thirds in Brussels and Luxembourg.  The Headquarters in Geneva deals with the management and negotiation of free trade agreements with non-EU countries, and provides support to the EFTA Council.  In Brussels, the Secretariat provides support for the management of the EEA Agreement and assists the Member States in the preparation of new legislation for integration into the EEA Agreement. The Secretariat also assists the Member States in the elaboration of input to EU decision making.  The two duty stations work together closely to implement the Vaduz Convention's stipulations on the intra-EFTA Free Trade Area.  The EFTA Statistical Office in Luxembourg contributes to the development of a broad and integrated European Statistical System. The EFTA Statistical Office (ESO) is located in the premises of Eurostat, the Statistical Office of the European Union in Luxembourg, and functions as a liaison office between Eurostat and the EFTA National Statistical Institutes. ESO's main objective is to promote the full inclusion of the EFTA States in the European Statistical System, thus providing harmonised and comparable statistics to support the general cooperation process between EFTA and the EU within and outside the EEA Agreement. The cooperation also entails technical cooperation programmes with third countries and training of European statisticians.

Locations.

The EFTA Secretariat is headquartered in Geneva, Switzerland, but also has duty stations in Brussels, Belgium and Luxembourg City, Luxembourg. The EFTA Surveillance Authority has its headquarters in Brussels, Belgium (the same location as the headquarters of the European Commission), while the EFTA Court has its headquarters in Luxembourg City (the same location as the headquarters of the European Court of Justice).

Relationship with the European Union: the European Economic Area.

In 1992, the EFTA and the EU signed the European Economic Area Agreement in Oporto, Portugal. However, the proposal that Switzerland ratify its participation was rejected by referendum. (Nevertheless, Switzerland has multiple bilateral treaties with the EU that allow it to participate in the European Single Market, the Schengen Agreement and other programmes). Thus, except for Switzerland, the EFTA members are also members of the European Economic Area (EEA). The EEA comprises three member states of the European Free Trade Association (EFTA) and 28 member states of the European Union (EU), including Croatia which is provisionally applying the agreement pending its ratification by all EEA countries. It was established on 1 January 1994 following an agreement with the European Community (which had become the EU two months earlier). It allows the EFTA-EEA states to participate in the EU's Internal Market without being members of the EU. They adopt almost all EU legislation related to the single market, except laws on agriculture and fisheries. However, they also contribute to and influence the formation of new EEA relevant policies and legislation at an early stage as part of a formal decision-shaping process. One EFTA member, Switzerland, has not joined the EEA but has a series of bilateral agreements, including a free trade agreement, with the EU.  The following table summarises the various components of EU laws applied in the EFTA countries and their sovereign territories. Some territories of EU member states also have a special status in regard to EU laws applied as is the case with some European microstates.

EEA institutions.

A Joint Committee consisting of the EEA-EFTA States plus the European Commission (representing the EU) has the function of extending relevant EU law to the non EU members. An EEA Council meets twice yearly to govern the overall relationship between the EEA members.  Rather than setting up pan-EEA institutions, the activities of the EEA are regulated by the EFTA Surveillance Authority and the EFTA Court. The EFTA Surveillance Authority and the EFTA Court regulate the activities of the EFTA members in respect of their obligations in the European Economic Area (EEA). Since Switzerland is not an EEA member, it does not participate in these institutions.  The EFTA Surveillance Authority performs a role for EFTA members that is equivalent to that of the European Commission for the EU, as "guardian of the treaties" and the EFTA Court performs the European Court of Justice-equivalent role.  The original plan for the EEA lacked the EFTA Court or the EFTA Surveillance Authority: the European Court of Justice and the European Commission were to exercise those roles. However, during the negotiations for the EEA agreement, the European Court of Justice informed the Council of the European Union by way of letter that it considered that it would be a violation of the treaties to give to the EU institutions these powers with respect to non-EU member states. Therefore, the current arrangement was developed instead.

EEA and Norway Grants.

The EEA and Norway Grants are the financial contributions of Iceland, Liechtenstein and Norway to reduce social and economic disparities in Europe. They were established in conjunction with the 2004 enlargement of the European Economic Area (EEA), which brought together the EU, Iceland, Liechtenstein and Norway in the Internal Market. In the period from 2004 to 2009, €1.3 billion of project funding was made available for project funding in the 15 beneficiary states in Central and Southern Europe. The EEA and Norway Grants are administered by the Financial Mechanism Office, which is affiliated to the EFTA Secretariat in Brussels.

International conventions.

EFTA also originated the Hallmarking Convention and the Pharmaceutical Inspection Convention, both of which are open to non-EFTA states.

International trade relations.

EFTA has several free trade agreements with non-EU countries as well as declarations on cooperation and joint workgroups to improve trade. Currently, the EFTA States have established preferential trade relations with 24 states and territories, in addition to the 28 member states of the European Union.  EFTA's interactive Free Trade Map gives an overview of the partners worldwide.

Travel policies.

Free movement of people within EFTA and the EU/EEA.

EFTA member states' citizens enjoy freedom of movement in each other's territories in accordance with the EFTA convention. EFTA nationals also enjoy freedom of movement in the European Union (EU). EFTA nationals and EU citizens are not only visa-exempt but are legally entitled to enter and reside in each other's countries. The Citizens’ Rights Directive (also sometimes called the "Free Movement Directive") defines the right of free movement for citizens of the European Economic Area (EEA), which includes the three EFTA members Iceland, Norway and Liechtenstein plus the member states of the EU. Switzerland, which is a member of EFTA but not of the EEA, is not bound by the Directive but rather has a separate bilateral agreement on free movement with the EU.  As a result a citizen of an EFTA country can live and work in all the other EFTA countries and in all the EU countries, and a citizen of an EU country can live and work in all the EFTA countries (but for voting and working in sensitive fields, such as government / police / military, citizenship is often required, and non-citizens may not have the same rights to welfare and unemployment benefits as citizens).

Dual citizenship.

Since each EFTA and EU country can make its own citizenship laws, dual citizenship is not always possible. Of the EFTA countries, Iceland, Norway and Switzerland allow it (in Switzerland, the conditions for the naturalization of immigrants vary regionally), while Liechtenstein allows it only for citizens by descent, but not for foreigners wanting to naturalize.  Some non-EFTA/non-EU countries do not allow dual citizenship either, so immigrants wanting to naturalize must sometimes renounce their old citizenship.  See also multiple citizenship and the nationality laws of the countries in question for more details.

Other.

Portugal Fund.

The Portugal Fund came into operation in February 1977 when Portugal was still a member of EFTA. It was to provide funding for the development of Portugal after the Carnation Revolution and the consequential restoration of democracy and the decolonization of the country's overseas possessions. This followed a period of economic sanctions by most of the international community, which left Portugal economically underdeveloped compared to the rest of the western Europe. When Portugal left EFTA in 1985 in order to join the EEC, the remaining EFTA members decided to continue the Portugal Fund so that Portugal would continue to benefit from it. The Fund originally took the form of a low-interest loan from the EFTA member states to the value of US$100 million. Repayment was originally to commence in 1988, however, EFTA then decided to postpone the start of repayments until 1998. The Portugal Fund was dissolved in January 2002.

The European Free Trade Association (EFTA) is a regional trade organization and free trade area consisting of four European states: Iceland, Liechtenstein, Norway, and Switzerland. The organization operates in parallel with the European Union (EU), and all four member states participate in the European Single Market and are part of the Schengen Area. They are not, however, party to the European Union Customs Union.

欧洲自由贸易协会(,缩写为)是欧洲一个促进贸易的组织。该组织于1960年5月3日成立。成员国有冰岛、挪威、瑞士以及列支敦士登,前成员国有联合王国、奥地利、葡萄牙、丹麦、瑞典以及芬兰。欧洲自由贸易协会会议于1960年1月4日于瑞典首都斯德哥尔摩举行,参与国家为上述七个国家,并合称为「外七国」。随着联盟改变瓦都兹会议已经取代斯德哥尔摩会议。这个会议给予成员国更进一步的贸易自由,冰岛、挪威、列支敦士登都加入了欧洲经济区,瑞士未加入欧洲经济区。公投否决参加。瑞士另外透过参与欧洲单一市场。


瓦尔代克和皮尔蒙特亲王国

History.

Waldeck was a county within the Holy Roman Empire from about 1200. Its counts included Adolf II of Waldeck from 1270 to 1276. In 1655, its seat and the chief residence of its rulers shifted from the castle and small town of Waldeck, overlooking the Eder river and first mentioned in 1120, to Arolsen. In 1625, the small county of Pyrmont became part of the county through inheritance. In January 1712, the count of Waldeck and Pyrmont was elevated to prince by Charles VI, Holy Roman Emperor. For a brief period, 1805 to 1812, Pyrmont was a separate principality as a result of inheritance and partition after the death of the previous prince, but the two parts were united again in 1812. The independence of the principality was confirmed in 1815 by the Congress of Vienna, and Waldeck and Pyrmont became a member of the German Confederation. From 1868 onward, the principality was administered by Prussia, but retained its legislative sovereignty. Prussian administration served to reduce administrative costs for the small state and was based on a ten-year contract that was repeatedly renewed for the duration of its existence. In 1871, the principality became a constituent state of the new German Empire. At the end of World War I, during the German Revolution that resulted in the fall of all the German monarchies, the prince abdicated and the principality became the Free State of Waldeck-Pyrmont within the Weimar Republic.  The princely house of Waldeck and Pyrmont is closely related to the royal family of the Netherlands. The last ruling prince, Frederick, was the brother of Queen consort Emma of the Netherlands.  In 1905, Waldeck and Pyrmont had an area of 1121 km and a population of 59,000.

Military.

Waldeck had raised a battalion of infantry in 1681 but for much of the subsequent history leading up to the Napoleonic Wars, Waldeckers generally served as'mercenaries' (actually hired out by the rulers of Waldeck) in foreign service. Such was the demand that the single battalion became two in 1740 (the 1st Regiment), three battalions in 1744, four in 1767 (forming a 2nd Regiment) and in 1776 a third regiment (5th and 6th Battalions) was raised. Most notably the foreign service was with the Dutch (the 1st and 2nd Regiments) and English (the 3rd Regiment)—the latter using them to suppress rebellions in the colonies. The 3rd Waldeck Regiment thus served during the American War of Independence, where they were known under the 'umbrella term' used during that conflict for all Germans—'Hessians'. The regiment was captured by the Americans and only a small number returned to Germany, where some formed part of a newly raised 5th Battalion (1784).  By the time of Napoleon's conquest of Germany, the Waldeck Regiments in Dutch service had been dissolved when, as the Batavian Republic, Holland was made into a kingdom ruled by Napoleon's brother Louis. Reduced to battalion strength, they now formed the 3rd battalions of the 1st and 2nd Infantry Regiments of the Kingdom of Holland. The 5th Battalion was disbanded, and Waldeck was now also obliged to provide two companies to the II Battalion, 6th German Confederation (i.e., Confederation of the Rhine) Regiment (along with two companies from Reuß) in the service of the French Empire. As with all French infantry, they were referred to as 'Fusiliers'. They served mainly in the Peninsula War against the Duke of Wellington. In 1812, the 6th Confederation Regiment was re-formed, with three companies from Waldeck and one from Reuß again forming the II Battalion. By the time of the downfall of the French Empire in 1814 the battalions in Dutch service had disappeared, but Waldeck now supplied three Infantry and one Jäger Companies to the newly formed German Confederation. By 1866, the Waldeck contingent was styled "Fürstlisches Waldecksches Füselier-Bataillon", and in the Austro-Prussian War of that year Waldeck (already in a military convention with Prussia from 1862) allied with the Prussians; however the Battalion saw no action. Joining the North German Confederation after 1867, under Prussian leadership, the Waldeck Fusilier Battalion became the III (Fusilier) Battalion of the Prussian Infantry Regiment von Wittich (3rd Electoral Hessian) No. 83, and as such it remained until 1918. The position of regimental 'Chef' (an honorary title) was held by the Prince of Waldeck and Pyrmont.  Unlike Hesse-Darmstadt, Hesse-Kassel (or Hesse-Cassel) retained no distinctions to differentiate them from the Prussian. The Waldeckers however, were permitted the distinction of carrying the Cockade of Waldeck on the Pickelhaube. The Waldeck battalion was garrisoned, at various times, at Arolsen/Mengeringhausen/Helsen, Bad Wildungen, Bad Pyrmont and Warburg.  The regiment saw action in the Franco-Prussian War of 1870 (where it acquired the nickname "Das Eiserne Regiment"), and during the First World War—as part of the 22nd Division—fought mainly on the Eastern Front.

The County of Waldeck (later the Principality of Waldeck and Principality of Waldeck and Pyrmont) was a state of the Holy Roman Empire and its successors from the late 12th century until 1929. In 1349 the county gained Imperial immediacy and in 1712 was raised to the rank of Principality. After the dissolution of the Holy Roman Empire in 1806 it was a constituent state of its successors: the Confederation of the Rhine, the German Confederation, the North German Confederation, the German Empire and, until 1929, the Weimar Republic. It comprised territories in present-day Hesse and Lower Saxony (Germany).

瓦尔代克位于当今德意志联邦共和国黑森州和下萨克森州交界一带。12世纪成为神圣罗马帝国的一个伯国。瓦尔代克的统治者来自施瓦伦贝格的领主家族。1474年分裂为两支,1692年重新合并。1712年,瓦尔代克伯爵被皇帝卡尔六世升为亲王。1918年德国君主制覆亡,瓦尔代克亲王失去了领土,但仍保有亲王的头衔。


History and mythology.

Carina was once a part of Argo Navis, the great ship of Jason and the Argonauts who searched for the Golden Fleece. The constellation of Argo was introduced in ancient Greece. However, due to the massive size of Argo Navis and the sheer number of stars that required separate designation, Nicolas Louis de Lacaille divided Argo into three sections in 1763, including Carina (the hull or keel). In the 19th century, these three became established as separate constellations, and were formally included in the list of 88 modern IAU constellations in 1930. Lacaille kept a single set of Greek letters for the whole of Argo, and separate sets of Latin letter designations for each of the three sections. Therefore, Carina has the α, β and ε, Vela has γ and δ, Puppis has ζ, and so on.

Notable features.

Stars.

Carina contains Canopus, a white-hued supergiant that is the second brightest star in the night sky at magnitude −0.72. Alpha Carinae, as Canopus is formally designated, is 313 light-years from Earth. Its traditional name comes from the mythological Canopus, who was a navigator for Menelaus, king of Sparta.  There are several other stars above magnitude 3 in Carina. Beta Carinae, traditionally called Miaplacidus, is a blue-white hued star of magnitude 1.7, 111 light-years from Earth. Epsilon Carinae is an orange-hued giant star similarly bright to Miaplacidus at magnitude 1.9; it is 630 light-years from Earth. Another fairly bright star is the blue-white hued Theta Carinae; it is a magnitude 2.7 star 440 light-years from Earth. Theta Carinae is also the most prominent member of the cluster IC 2602. Iota Carinae is a white-hued supergiant star of magnitude 2.2, 690 light-years from Earth.  Eta Carinae is the most prominent variable star in Carina; with a mass of approximately 100 solar masses and 4 million times as bright as the Sun. It was first discovered to be unusual in 1677, when its magnitude suddenly rose to 4, attracting the attention of Edmond Halley. Eta Carinae is inside NGC 3372, commonly called the Carina Nebula. It had a long outburst in 1827, when it brightened to magnitude 1, only fading to magnitude 1.5 in 1828. Its most prominent outburst made Eta Carinae the equal of Sirius; it brightened to magnitude −1.5 in 1843. In the decades following 1843 it appeared relatively placid, having a magnitude between 6.5 and 7.9. However, in 1998, it brightened again, though only to magnitude 5.0, a far less drastic outburst. Eta Carinae is a binary star, with a companion that has a period of 5.5 years; the two stars are surrounded by the Homunculus Nebula, which is composed of gas that was ejected in 1843.  There are several less prominent variable stars in Carina. l Carinae is a Cepheid variable noted for its brightness; it is the brightest Cepheid that is variable to the unaided eye. It is a yellow-hued supergiant star with a minimum magnitude of 4.2 and a maximum magnitude of 3.3; it has a period of 35.5 days.  Two bright Mira variable stars are in Carina: R Carinae and S Carinae; both stars are red giants. R Carinae has a minimum magnitude of 10.0 and a maximum magnitude of 4.0. Its period is 309 days and it is 416 light-years from Earth. S Carinae is similar, with a minimum magnitude of 10.0 and a maximum magnitude of 5.0. However, S Carinae has a shorter period – 150 days, though it is much more distant at 1300 light-years from Earth.  Carina is home to several double stars and binary stars. Upsilon Carinae is a binary star with two blue-white hued giant components, 1600 light-years from Earth. The primary is of magnitude 3.0 and the secondary is of magnitude 6.0; the two components are distinguishable in a small amateur telescope.  Two asterisms are prominent in Carina. One is known as the 'Diamond Cross', which is larger than the Southern Cross (but fainter), and, from the perspective of the southern hemisphere viewer, upside down, the long axes of the two crosses being close to parallel. Another asterism in the constellation is the False Cross, often mistaken for the Southern Cross, which is an asterism in Crux. The False Cross consists of two stars in Carina, Iota Carinae and Epsilon Carinae, and two stars in Vela, Kappa Velorum and Delta Velorum.

Deep-sky objects.

Carina is known for its namesake nebula, NGC 3372, discovered by French astronomer Nicolas Louis de Lacaille in 1751, which contains several nebulae. The Carina Nebula overall is an extended emission nebula approximately 8,000 light-years away and 300 light-years wide that includes vast star-forming regions. It has an overall magnitude of 8.0 and an apparent diameter of over 2 degrees. Its central region is called the Keyhole, or the Keyhole Nebula. This was described in 1847 by John Herschel, and likened to a keyhole by Emma Converse in 1873. The Keyhole is about seven light-years wide and is composed mostly of ionized hydrogen, with two major star-forming regions. The Homunculus Nebula is a planetary nebula visible to the naked eye that is being ejected by the erratic luminous blue variable star Eta Carinae, the most massive visible star known. Eta Carinae is so massive that it has reached the theoretical upper limit for the mass of a star and is therefore unstable. It is known for its outbursts; in 1840 it briefly became one of the brightest stars in the sky due to a particularly massive outburst, which largely created the Homunculus Nebula. Because of this instability and history of outbursts, Eta Carinae is considered a prime supernova candidate for the next several hundred thousand years because it has reached the end of its estimated million-year life span.  NGC 2516 is an open cluster that is both quite large (approximately half a degree square) and bright, visible to the unaided eye. It is located 1100 light-years from Earth and has approximately 80 stars, the brightest of which is a red giant star of magnitude 5.2. NGC 3114 is another open cluster approximately of the same size, though it is more distant at 3000 light-years from Earth. It is more loose and dim than NGC 2516, as its brightest stars are only 6th magnitude. The most prominent open cluster in Carina is IC 2602, also called the "Southern Pleiades". It contains Theta Carinae, along with several other stars visible to the unaided eye. In total, the cluster possesses approximately 60 stars. The Southern Pleiades is particularly large for an open cluster, with a diameter of approximately one degree. Like IC 2602, NGC 3532 is visible to the unaided eye and is of comparable size. It possesses approximately 150 stars that are arranged in an unusual shape, approximating an ellipse with a dark central area. Several prominent orange giants are among the cluster's bright stars, of the 7th magnitude. Superimposed on the cluster is Chi Carinae, a yellow-white hued star of magnitude 3.9, far more distant than NGC 3532.  Carina also contains the naked-eye globular cluster NGC 2808. Epsilon Carinae and Upsilon Carinae are double stars visible in small telescopes.  One noted galaxy cluster is 1E 0657-56, the Bullet Cluster. At a distance of 4 billion light years (redshift 0.296), this galaxy cluster is named for the shock wave seen in the intracluster medium, which resembles the shock wave of a supersonic bullet. The bow shock visible is thought to be due to the smaller galaxy cluster moving through the intracluster medium at a relative speed of 3000–4000 kilometers per second to the larger cluster. Because this gravitational interaction has been ongoing for hundreds of millions of years, the smaller cluster is being destroyed and will eventually merge with the larger cluster.

Meteors.

Carina contains the radiant of the Eta Carinids meteor shower, which peaks around January 21 each year.

Equivalents.

From China (especially northern China), the stars of Carina can barely be seen. The star Canopus (the south polar star in Chinese astronomy) was located by Chinese astronomers in the Vermilion Bird of the South (南方朱雀, "Nán Fāng Zhū Què"). The rest of the stars were first classified by Xu Guanggi during the Ming Dynasty, based on the knowledge acquired from western star charts, and placed among The Southern Asterisms (近南極星區, "Jìnnánjíxīngōu").  Polynesian peoples had no name for the constellation in particular, though they had many names for Canopus. The Māori name "Ariki" ("High-born"),. and the Hawaiian "Ke Alii-o-kona-i-ka-lewa", "The Chief of the southern expanse". both attest to the star's prominence in the southern sky, while the Māori "Atutahi", "First-light" or "Single-light", and the Tuamotu "Te Tau-rari" and "Marere-te-tavahi", "He-who-stands-alone". refer to the star's solitary nature. It was also called "Kapae-poto", ("Short horizon"), because it rarely sets from the vantage point of New Zealand; and "Kauanga" ("Solitary"), when it was the last star visible before sunrise.

Future.

Carina is in the southern sky quite near the south celestial pole, making it never set (circumpolar) for most of the southern hemisphere. Due to precession of Earth's axis, by the year 4700 the south celestial pole will be in Carina. Three bright stars in Carina will come within 1 degree of the southern celestial pole and take turns as the southern pole star: Omega Carinae (mag 3.29) in 5600, Upsilon Carinae (mag 2.97) in 6700, and Iota Carinae (mag 2.21) in 7900. About 13860, the bright Canopus (-0.7) will have a greater declination than -82°.

Namesakes.

was a United States Navy Crater class cargo ship named after the constellation.

Carina ( (U.S.) (Brit.)) is a constellation in the southern sky. Its name is Latin for the hull or keel of a ship, and it was the southern foundation of the larger constellation of Argo Navis (the ship "Argo") until it was divided into three pieces, the other two being Puppis (the poop deck), and Vela (the sails of the ship).

船底座(Carina IPA:, 意为龙骨)是天舟座的一部分,到十八世纪法国人拉卡伊把天舟座分成三个星座:船底座、船帆座和船尾座,他是在南天的星座,原本是古老的南船座的一部分。他拥有全天第二亮的老人星,和镶嵌在卡利纳星云(NGC 3372)中的超重巨星海山二(船底座η星)。


Notation.

The complex conjugate of a complex number formula_7 is written as formula_8 or formula_9. The first notation, a vinculum, avoids confusion with the notation for the conjugate transpose of a matrix, which can be thought of as a generalization of the complex conjugate. The second is preferred in physics, where dagger (†) is used for the conjugate transpose, while the bar-notation is more common in pure mathematics. If a complex number is represented as a 2×2 matrix, the notations are identical. In some texts, the complex conjugate of a previous known number is abbreviated as "c.c.". For example, writing formula_10 means formula_11.

Properties.

The following properties apply for all complex numbers "z" and "w", unless stated otherwise, and can be proved by writing "z" and "w" in the form "a" + "bi".  For any two complex numbers "w,z":  Conjugation is distributive over addition, subtraction, multiplication and division.  Real numbers are the only fixed points of conjugation. A complex number is equal to its complex conjugate if its imaginary part is zero.  Composition of conjugation with the modulus is equivalent to the modulus alone.  Conjugation is an involution; i.e., the conjugate of the conjugate of a complex number "z" is "z".  The product of a complex number with its conjugate is equal to the square of the number's modulus. This allows easy computation of the inverse of a complex number given in rectangular coordinates.  Furthermore, formula_21 can be used to specify lines in the plane: the set  is a line through the origin and perpendicular to formula_23 since the real part of formula_24 is zero only when the cosine of the angle between formula_7 and formula_23 is zero. Similarly, for a fixed complex unit, the equation  determines the line through formula_28 parallel to the line through 0 and "u".  These uses of the conjugate of "z" as a variable are illustrated in Frank Morley's book "Inversive Geometry" (1933), written with his son Frank Vigor Morley.

Generalizations.

The other planar real algebras, dual numbers, and split-complex numbers are also analyzed using complex conjugation.  For matrices of complex numbers formula_29, where formula_30 represents the element-by-element conjugation of formula_31. Contrast this to the property formula_32, where formula_33 represents the conjugate transpose of formula_34.  Taking the conjugate transpose (or adjoint) of complex matrices generalizes complex conjugation. Even more general is the concept of adjoint operator for operators on (possibly infinite-dimensional) complex Hilbert spaces. All this is subsumed by the *-operations of C*-algebras.  One may also define a conjugation for quaternions and split-quaternions: the conjugate of formula_35 is formula_36.  All these generalizations are multiplicative only if the factors are reversed:  Since the multiplication of planar real algebras is commutative, this reversal is not needed there.  There is also an abstract notion of conjugation for vector spaces formula_38 over the complex numbers. In this context, any antilinear map formula_39 that satisfies  is called a "complex conjugation", or a real structure. As the involution formula_50 is antilinear, it cannot be the identity map on formula_51.  Of course, formula_52 is a formula_53-linear transformation of formula_38, if one notes that every complex space "V" has a real form obtained by taking the same vectors as in the original space and restricting the scalars to be real. The above properties actually define a real structure on the complex vector space formula_51.  One example of this notion is the conjugate transpose operation of complex matrices defined above. It should be remarked that on generic complex vector spaces there is no "canonical" notion of complex conjugation.

In mathematics, the complex conjugate of a complex number is the number with an equal real part and an imaginary part equal in magnitude but opposite in sign. For example, (if "a" and "b" are real, then) the complex conjugate of formula_1 is formula_2

在数学中,复数的共轭复数(常简称共轭)是对虚部变号的运算,因此一个复数formula_1的共轭可以表示为: