| 释义 |
oersted Physics.|ˈɜːstɛd|
[f. the name of H. C. Oersted (1777–1851), Danish physicist.]
†a. (Written oerstedt.) (See quots.) Obs.
1879J. D. Everett Units & Physical Constants xi. 139 The practical unit of current is the current due to an electromotive force of 1 volt working through a resistance of 1 ohm. It is called a current of 1 weber per second. Its theoretical value is 1 weber per second = 1/10 of the C.G.S. unit of current. In the ‘Testing Instructions of the Indian Telegraph Department’ it is called the Oerstedt. 1885W. Williams Man. Telegr. 206 The unit current..has already been described as the Ampère or Oerstedt.
†b. The electromagnetic unit of reluctance in the C.G.S. system, defined as one gilbert per maxwell. (In the International System of Units replaced by the reciprocal heury, equal to approximately 1·26 × 10-8 gilberts per maxwell.) Obs.
1893[see gilbert2]. 1896M. Maclean Physical Units 92 The committee on Notation of the Chamber of Delegates of the International Electrical Congress of 1893 in Chicago recommended that—unit field intensity, unit magnetic induction, and unit magnetising force be each called a Gauss; unit flux of magnetic force a Weber; unit magneto-motive force a Gilbert; and unit reluctance or magnetic resistance an Oersted. 1903Electr. World & Engin. XLI. 1010/2 For practical work..the magnetic reluctance of a cubic centimeter of all non-magnetic materials..is the same as that of an air-pump vacuum. This unit of reluctance is called the ‘oersted’. 1931S. R. Williams Magn. Phenomena i. 46 The oersted of reluctance corresponds to the ohm of resistance.
c. The electromagnetic unit of magnetic field strength in the C.G.S. system, equal to the field strength produced at a distance of one centimetre by a unit magnetic pole or a thin straight wire carrying half an e.m.u. (i.e. five amp.) of current; one maxwell per square centimetre. Cf. gauss. (In the International System of Units the oersted is replaced by the ampere per metre, equal to 4π × 10-3 (approximately 0·0126) oersted.)
1930Engineering 25 July 113/2 At the meeting of the International Electrotechnical Commission..it was..recommended that the names of maxwell, gauss, oersted and gilbert should be applied to the C.G.S. units for magnetic flux, flux density, magnetic field intensity and magneto-motive force respectively. 1938R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity (ed. 2) ii. 26 By means of deflexion experiments in very strong magnetic fields (23,000 oersteds) a fine structure of the α-particles from thorium C..has been detected. 1959Sci. News LI. 17 For instance, at a temperature of 0·01° K a magnetic field of the order of 100,000 oersted is needed in order to achieve the necessary nuclear alignment for the subsequent cooling by demagnetization. 1962[see gauss]. 1963Jerrard & McNeill Dict. Sci. Units 97 The earth's magnetic field has a magnetizing force of the order 0·2 to 0·3 oersted. 1974Nature 16 Aug. 535/2 Few, if any [geomagneticians] have really cared whether their magnetometers have measured B or H; the gauss, the c.g.s. unit of B, has by usage become totally interchangeable with the oersted, the c.g.s. unit of H. 1976Ibid. 26 Feb. 652/1 All 36 specimens were submitted to magnetic study, including alternating field treatment up to 850 oersted. |