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| 放射化学 |
放射化学放射化学，在化学中有关原子能的一门学科。
Category:化学
th:เคมีนิวเคลียร์
化学
化学研究物质的性质、组成、结构和变化的科学。中国古代在陶瓷、染色、酿造、造纸、火药等化学工艺方面成就杰出。
化學的早期歷史主要都是與金屬的提取和處理有關。2000年前，人類己廣泛使用金，銀，汞(水銀)，銅，鐵和青銅。
中国古代的炼丹术，西方古代的炼金术，就部分含有化学的雏形，并对近代化学的形成、发展有重大意义。
1800年裏(公元前300-1500年)，煉金術士的主要興趣是將一些便宜的金屬轉化成黃金。跟着的一百年是醫療化學的世紀,因為那時候化學家主要的工作是製造藥物。
古化學家收集了很多不同物質的資料。但是化學的發展到了16世紀還是很慢。在17世紀出現了好幾位大化學家，其中之一是罗伯特·波义耳，他被尊崇為化學之父。
在這之後，很多新發現一個接着一個的出現。到了1850年，化學己與現在所熟知的甚為相似。
当前的化学已从改造天然物质、仿制天然物质向设计功能物质方向迈进。在分子水平上设计制造具有直接功能（如：分辨功能、记忆功能）的材料已不是空想。
学科分类
- 无机化学
- 元素化学
- 无机合成化学
- 配位化学
- 配位聚合物化学
- 无机固態化学
- 有机金属化学
- 生物无机化学
- 有机化学
- 天然有机化学
- 有机合成化学
- 元素有机化学
- 物理有机化学
- 有机分析
- 有機光譜學
- 紅外光譜學
- 核磁共振光譜學
- 紫外光可見光光譜學
- 物理化学
- 化学热力学
- 溶液的性质和溶液理论
- 结构化学
- 量子化学
- 磁化学
- 晶体化学
- 化学动力学
- 催化化学
- 热化学
- 光化学
- 分析化学
- 定性分析
- 定量分析
- 仪器分析
- 电化学分析
- 光学分析
- 放射化学分析
- 结构分析
- 官能团分析
- 立体化学分析
- 高分子化学
- 高分子合成
- 天然高分子
- 高分子物理化学
- 高分子物理
- 放射化学
- 放射性元素
- 核化学
- 放射分析化学
- 同位素化学
- 辐射化学
- 核燃料、反应堆和裂变产物化学
- 其他分支
- 计算化学
- 生物化学
- 地球化学
- 海洋化学
- 大气化学
- 环境化学
- 宇宙化学
- 星际化学
- 药物化学
- 农业化学
- 石油化学
- 木材化学
- 土壤化学
- 化学分类学
- 化学胚胎学
- 化学工程
- 煤化学
- 食品化学
- 化学地理学
- 天体化学
- 岩石化学
- 空间化学
- 化学加工
- 石油化工
- 化学史
- 电化学
参看
- 诺贝尔化学奖
- 元素列表
- 化学工业
- 化学品列表
- 化学术语列表
- 元素周期表
- 化学家
Category:化学Category:自然科学
als:Chemie
ja:化学
ko:화학
ms:Kimia
simple:Chemistry
th:เคมี
Category:化学化学是研究物质的性质、组成、结构和变化的自然科学。
参看Wikipedia:化学首页。
Category:自然科学
als:Kategorie:Chemie
ja:Category:化学
ko:분류:화학
ms:Category:Kimia
th:Category:เคมี
Track and field athlete:This article refers to the British English definition of Athletics that is limited in scope to sporting events that in American English are known as "Track and Field". Thus, Track and Field redirects here. If you are looking for the American English definition of the word "athletics", which is used to categorise all sports, please see the article entitled Sport.
Athletics, also known as track and field or track and field athletics, is a collection of sport events. The word is derived from the Greek word "athlos" meaning "contest". It is a collection of sport events, which can roughly be divided into running, throwing, and jumping.
History
Athletics was the original sport at the first Olympics back in 776 BC where the only event held was the stadium-length foot race or "stade". The earliest recorded win was at these games in the stade race.
There were several other "Games" held throughout Europe in later eras:
- The Pythian Games (founded 527 BC) held in Delphi every four years
- The Nemean Games (founded 516 BC) held in Argolid every two years
- The Isthmian (founded 523 BC) held on the Isthmus of Corinth every two years (one year being that which followed the Olympics)
- The Roman Games — a direct imitation of the Greek Olympics, however was a much more popularized spectacle, with most competitors likely to have been professional athletes (the Greek Olympics was more a common-man's fare). Many themes of the Roman Circus (chariot races, gladiatorial combats and wild animal displays) were incorporated into the Roman Games asides from athletic sports.
Other peoples enjoyed athletic contests, such as the Celts, Teutons and Goths who succeeded the Romans. However these were often related to training to war, and were not very well organized. In the Middle Ages the sons of noblemen would be trained in running, leaping and wrestling, in addition to riding, jousting and arms-training. Contests between rivals and friends may have been common on both official and unofficial grounds.
Many athletic sports have found favour in Europe throughout the ages. However, at least in Britain, they fell out favour between the 13th and 16th centuries due to government restrictions on sports aiming to reduce the practice of archery. After this ban was lifted in the 17th century sports began to flourish once more, but it was not until the 19th century that organization began to appear. This included the incorporation of regular sports and exercise into school regimes. The Royal Military College, Sandhurst has claimed to be the first to adopt this in 1812 and 1825 but without any supporting evidence. The earliest recorded meeting was organised at Shrewsbury, Shropshire in 1840 by the Royal Shrewsbury School Hunt. There are details of the meeting in a series of letters written 60 years later by CT Robinson who was a pupil there from 1838 to 1841.
Modern athletic events are usually organized around a 400 metre running track, on which most of the running events take place. Field events (jumping and throwing) often take place in the field in the centre of the running track.
Many athletic events have an ancient origin and were already conducted in competitive form by the ancient Greeks. Athletics was included in the first modern Olympic Games in 1896 and has been part of the program ever since, providing the backbone of the Olympics. Women were not allowed to participate in track and field events in the Olympics until 1928.
An international governing body, the IAAF was founded in 1912. The IAAF established separate outdoor World Championships in 1983. The AAU (Amateur Athletic Union) was the governing body in the United States until it collapsed under pressure from advancing professionalism in the late 1970s. A new governing body called The Athletics Congress (TAC) was formed, it was later renamed USA Track and Field (USATF or USA T&F). An additional, less structured organization, the Road Runners Club of America (RRCA) also exists in the USA to promote road racing. Both organizations allow athletes to receive money for racing putting an end to the "shamateurism" that existed before.
Indoor track and field
There are two seasons for track and field. There is an indoor season, run during the winter and an outdoor season, run during the summer. Most indoor tracks are 200 meters, however, less frequently, there are smaller and larger tracks that measure from between 180 to 300 meters. The indoor track consists of four to six lanes instead of the eight to ten on an outdoor track. Often an indoor track will have banked turns to compensate for the tight bends.
In an indoor track meet athletes contest the same events as an outdoor meet with the exception of the 100 m and 110 m/100 m hurdles (replaced by the 60 m sprint and 60 m hurdles at all levels), and the 10,000 m run and 3,000 m steeplechase. Indoor meets also have the addition of a 3,000 m run , normally instead of the 5000m(at both the collegiate and elite level).
In the field events, indoor meetings only feature the high jump, pole vault, long jump, triple jump and shot put. The longer throws of javelin, hammer and discus are reserved for outdoor meetings, as there is normally not enough space in an indoor stadium to house these events.
Other events unique to indoor meets (especially in the United States) are the 300m, 600m, 1000m and 35 lb. weight throw.
For multi-event athletes there is the Pentathlon for women (consisting of 60m hurdles, high jump, shot put, long jump and 800m) and heptathlon for men (consisting of 60m, long jump, shot put, high jump, 60m hurdles, pole vault and 1000m).
Outdoor track and field
The outdoor track and field season begins in the spring and may last through the summer. Usually the tracks are 400 meters, however, some old tracks are still measured in yards, so they measure 440 yards. The track consists of 6-10 lanes and for the bigger collegiate tracks, a steeplechase lane with a water pit. This can be inside or outside the track, making for a tighter turn or a wider turn. Often schools will place a field in the middle of the track, usually football/soccer/lacrosse, due to their size and shape. Recently these fields have been made out of astro turf or field turf instead of grass.
Field events consist of the high jump, pole vault, long jump, triple jump and shot put. They also consist of the javelin, hammer and discus throws; however, often these are outside of the stadium because they take up a large amount of space.
Events
There are other variations besides the ones listed below but races of unusual length (e.g. 300 m) are run much less often. With the exception of the mile run, races based on imperial distances are rarely run on the track anymore since most tracks have been converted from a quarter mile (402.3 m) to 400 meters.
Men and women do not compete against each other. Women generally run the same distances as men although hurdles and steeplechase barriers are lower and the weights of the shot, discus, javelin and hammer are less.
- Track events - running events conducted on a 400 meter track.
- Sprints: events up to and including 400 m. Common events are 60 m (indoors only), 100 m, 200 m and 400 m.
- Middle distance: events from 800 m to 3000 m, especially 800 m, 1500 m, mile and 3000 m.
- steeplechase - a race (usually 3000 m) in which runners must negotiate barriers and water jumps.
- Long distance: runs over 5000 m. Common events are 5000 m and 10000 m.
- Hurdling: 110 m high hurdles (100 m for women) and 400 m intermediate hurdles (300 m in high school).
- Relays: 4 x 100 m, 4 x 400 m, 4 x 200 m, 4 x 800 m, etc. Some events, such as medley relays, are rarely run except at large relay carnivals.
- Road running: conducted on open roads, but often finishing on the track. Common events are half-marathon and marathon.
- Race walking: usually conducted on open roads. Common events are 10 km, 20 km and 50 km.
- Field events
- Throwing events
- Shot put
- Hammer throw
- Javelin throw
- Discus throw
- Jumping events
- High jump
- Long jump
- Pole vault
- Triple jump
- Standing high jump
- Standing long jump
- Standing pole vault
- Standing triple jump
- Composite events
- Pentathlon
- Heptathlon
- Decathlon
World records
Men
Note : Two record distances are given for the men's javelin event ; this is because in the 1980s, the men's event was throwing at distances which caused many "flat landings" and judges at the event were having trouble discerning the exact point at which the javelin had landed and whether the throw was legal. In 1985, the specs of the javelin were changed by moving the centre of gravity forward by 4 cm.
Women
Note: As with the men's event, the specification of the women's javelin has been changed. On April 1, 1999 the IAAF moved the centre of gravity forward by 3 cm in order to ensure a greater number of legal throws and to allow for more accurate distance measurement.
The two tables above are mainly Outdoor world records. Indoor world records are available at [http://www.athletix.org/Statistics/ndwr.html Athletix.org].
See also
- Olympic medalists in athletics (men)
- Olympic medalists in athletics (women)
- World Record progression 100 m men
- World Record progression 100 m women
- World record progression for the mile run
- World Record progression Pole Vault men
- World Record progression Pole Vault women
- Muslim athletes
External links
- [http://www.iaaf.org/ IAAF International Association of Athletics Federations] - Official site
- [http://www.usatf.org/ USA Track & Field] - Official site
- [http://www.athletix.org/ World Record progression in athletics]
- [http://www.algonet.se/~pela2/ Track and Field all-time performances]
- Category:Olympic sports
ko:육상 경기
ja:陸上競技
simple:Athletics
th:กรีฑา
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