appleton- oshkosh

Appleton

Oshkosh

Appleton layer [ˈæpltən] s PHYS Appleton-Schicht (Teil der oberen Atmosphäre)

< geo> ■ Appleton-Schicht f

persamaan Appleton-Hartree

PHYS at canal-lock capa de Appleton f

capa de Appleton.

Oshkosh, nombre propio.

plural de UNIVERSITY OF WISCONSIN, OSHKOSH

SUBJECT AREA: Broadcasting, Telecommunications

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After early ambitions to become a professional cricketer, Appleton went to St John's College, Cambridge, where he studied under J.J.Thompson and Ernest Rutherford. His academic career interrupted by the First World War, he served as a captain in the Royal Engineers, carrying out investigations into the propagation and fading of radio signals. After the war he joined the Cavendish Laboratory, Cambridge, as a demonstrator in 1920, and in 1924 he moved to King's College, London, as Wheatstone Professor of Physics.

In the following decade he contributed to developments in valve oscillators (in particular, the "squegging" oscillator, which formed the basis of the first hard-valve time-base) and gained international recognition for research into electromagnetic-wave propagation. His most important contribution was to confirm the existence of a conducting ionospheric layer in the upper atmosphere capable of reflecting radio waves, which had been predicted almost simultaneously by Heaviside and Kennelly in 1902. This he did by persuading the BBC in 1924 to vary the frequency of their Bournemouth transmitter, and he then measured the signal received at Cambridge. By comparing the direct and reflected rays and the daily variation he was able to deduce that the Kennelly- Heaviside (the so-called E-layer) was at a height of about 60 miles (97 km) above the earth and that there was a further layer (the Appleton or F-layer) at about 150 miles (240 km), the latter being an efficient reflector of the shorter radio waves that penetrated the lower layers. During the period 1927–32 and aided by Hartree, he established a magneto-ionic theory to explain the existence of the ionosphere. He was instrumental in obtaining agreement for international co-operation for ionospheric and other measurements in the form of the Second Polar Year (1932–3) and, much later, the International Geophysical Year (1957–8). For all this work, which made it possible to forecast the optimum frequencies for long-distance short-wave communication as a function of the location of transmitter and receiver and of the time of day and year, in 1947 he was awarded the Nobel Prize for Physics.

He returned to Cambridge as Jacksonian Professor of Natural Philosophy in 1939, and with M.F. Barnett he investigated the possible use of radio waves for radio-location of aircraft. In 1939 he became Secretary of the Government Department of Scientific and Industrial Research, a post he held for ten years. During the Second World War he contributed to the development of both radar and the atomic bomb, and subsequently served on government committees concerned with the use of atomic energy (which led to the establishment of Harwell) and with scientific staff.

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эк. Метцлер, Ллойд Эплтон (1913-1980; американский экономист, занимавшийся исследованием деловых циклов и международной торговой политики)