| 释义 |
▪ I. ‖ electron1|ɪˈlɛktrən|
[a. Gr. ἤλεκτρον: see electrum.]
= electrum 2.
1856Grote Greece ii. xcviii. XII. 659 Precious metals (gold, silver, and electron). 1877W. Jones Finger-ring L. 459 Mediæval ring..formed of electron, or gold much alloyed with silver.
▪ II. electron2|ɪˈlɛktrɒn|
[f. electric a. + -on as in anion, cation, ion.]
A stable elementary particle which has an indivisible charge of negative electricity, is a constituent of all atoms, and is the carrier of electric current in solids; also, the anti-particle of this, having a positive instead of a negative charge (see positron). Orig. the name of the magnitude of the electronic charge.
1891G. J. Stoney in Trans. R. Dublin Soc. 2nd Ser. IV. 583 A charge of this amount is associated in the chemical atom with each bond...These charges, which it will be convenient to call electrons, cannot be removed from the atom; but they become disguised when atoms chemically unite. 1902Fortn. Rev. June 1023 Larmor's hypothesis of electrons, which supposes a kind of an electric atom, a charge not associated with ordinary matter. 1902Nature 18 Sept. 488 The conception..that the ultimate atoms of matter involve positive and negative electrons. 1902[see corpuscle 2 c]. 1927A. S. Eddington Stars & Atoms 16 The electron is the lightest thing known, weighing no more than 1/1,840 of the lightest atom. 1933Discovery Mar. 69/2 Experimentally there is now a case for the existence of a positive electron, and..this particle is apparently one of several pieces which can result from impact of matter in the atmosphere with the cosmic or pentrating radiation. 1955Sci. News Let. 30 Apr. 274/3 Electrons are light-weight, fundamental particles of the atom having a negative charge. 1958[see corpuscle 2 c]. 1968M. Livingston Particle Physics iv. 62 This has the effect of producing, out of energy, a pair of electrons, one with negative and one with positive charge.
b. fig.
1904Sat. Rev. 30 Jan. 138/1 Mr. Hardy's puppets are infinitesimal—mere ‘electrons’, shifted hither and thither, for no reason, by some impalpable agency. 1913Empire Rev. Dec. 1336 The imponderable electrons of sentiment and feeling which allow our far-away peoples and clans to cohere. 1929D. H. Lawrence Pansies 26 The swan within vast chaos, within the electron.
2. a. attrib.
1903Science 26 June 1001/2 The electron theory..explains Ampère's idea that magnetism is due to a rotating current of electricity round each atom of iron. 1921Discovery Sept. 226/2 The corresponding electron velocities are so small that it is difficult to measure them. Ibid., We must recognise that wave radiation and electron radiation are in a sense mutually convertible. 1923J. S. Huxley Essays of Biologist vii. 252 From this state there evolved one in which the various electron-systems that we call atoms first appeared. 1926Atlantic Monthly Apr. 377/2 The study of electron-emisssion has given us..radio broadcasting. 1926R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity iii. 42 The electron shells of the atoms. 1938Ibid. (ed. 2) iv. 90 The energy levels of atoms as established by experiments on electron collisions. 1955Bull. Atomic Sci. Mar. 94/3 The basic methods of operation of the synchrocyclotron, the electron synchrotron, the linear accelerator, and the proton synchrotron. 1955H. B. G. Casimir in W. Pauli Niels Bohr 120 In many metals the electron bands may well have a complicated structure. 1956Nature 10 Mar. 483/2 Straightforward hydrogen atom transfer, and electron transfer..followed by proton expulsion. 1962Listener 10 May 810/1 The living muscle is made up of atomic nuclei, mostly of carbon, linked together by fixed electron bonds. 1967New Scientist 21 Dec. 707/2 To understand the electron-transfer process in detail has proved to be a stiff test for the theoreticians.
b. Comb. electron beam, a beam or stream of electrons, a cathode-ray beam; electron camera Television (see quot. 1940); electron cloud, a cloud-like mass of electrons; electron diffraction [diffraction 1], the diffraction of a beam of electrons; electron gas, a system of free electrons; electron gun, a device in which electrons obtained by thermionic emission from a heated cathode are emitted as a narrow beam; electron lens (see quot. 1960); electron microgram = next; electron micrograph, a micrograph produced by an electron microscope; hence electron micrography; also electron micrographic; electron microscope [ad. G. elektronenmikroskop (E. Brüche 1932, in Naturwissensch. 15 Jan. 49)], a microscope in which the resolution and magnification of minute objects is obtained by the passage of a stream of electrons through a system of electron lenses (cf. microscope n. 1); hence electron microscopy; also electron microscopic, electron microscopical, electron microscopist; electron multiplier [multiplier 4], an instrument used for amplifying the intensity of a current of electrons; electron optics [ad. G. elektronenoptik (Knoll & Ruska 1932, in Ann. d. Physik XII. 607)], a branch of physics concerned with the influence of electric and magnetic fields on the movement of electrons (quot. 1916 represents a different sense); hence eˌlectron-ˈoptical a.; electron pair, (a) = duplet 2; (b) (see quot. 19551); electron spin, the intrinsic angular momentum of an electron, described by the quantum number s; the property of an electron by virtue of which it possesses this momentum; electron spin resonance, resonance (sense 1 d (iii)) in which the transition involved is that of electrons between states of different spin, esp. unpaired bound electrons in a paramagnetic ion; electron telescope, a telescope of electron-optical type in which the image is obtained by the use of infra-red rays; electron tube, a vacuum tube in which a current of electrons passes between electrodes; electron volt (abbrev. eV, e.V.), a unit of energy used in nuclear physics (see quot. 1962); electron wave, a (hypothetical) wave associated with the movement of an electron and held to account for its various wave-like properties; a de Broglie wave of an electron.
1927Physical Rev. Dec. 705 Electron beams resulting from diffraction by a nickel crystal. 1956Nature 3 Mar. 419/2 A series of remarkable electron micrographs..obtained by..using a new fine electron-beam technique. 1958O. R. Frisch Nuclear Handbk. vii. 5 The electron beam takes the place of the current in the secondary coil.
1937Discovery Nov. 329/1 The electron camera at the transmitter, with a cathode-ray tube at the receiving end. 1940Chambers's Techn. Dict., Electron camera, a generic term for any device which converts an optical image into a corresponding electric current directly by electronic means, without the intervention of mechanical scanning.
1926R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity vii. 62 Atomic sphere..at the disposal of the electrons... The dimensions of this electron cloud [etc.]. 1946Nature 16 Nov. 717/1 The electron-cloud in the outer incomplete shells of the atom or the molecule react on the nucleus.
1927Physical Rev. Dec. 705 The spacing factor concerned in electron diffraction by a nickel crystal. Ibid. 731 At sufficiently high voltages there is no difference between the occurrence of x-ray and electron diffraction beams. 1939Nature 25 Feb. 372/2 Messrs. W. Edwards and Co...have recently published details of their Finch electron diffraction camera intended for industrial research. 1958Jrnl. Iron & Steel Inst. CLXXXIX. 56/2 The marked thinness of the blades and prisms..resulted in electron diffraction patterns being observed.
1955H. B. G. Casimir in W. Pauli Niels Bohr 129 There is something rather tempting in the idea that due to some sort of interaction the electron gas ‘coagulates’ into blocks. 1962Listener 10 May 809/2 A few free electrons, drifting about hither and thither and forming an electron-gas in the metal.
1924Brass World Feb. 52/1 The electron gun is not swung about, but its stream of projectiles is deflected by means of electric or magnetic forces. 1930Chem. Abstr. 2044 The electron gun..consists of a hot filament near the small hole in a diaphragm and on the axis of a hollow cylinder at a pos. potential, which produces a ‘visible’ beam of electrons. 1953Amos & Birkinshaw Television Engin. I. iv. 52 The electron gun is an electrode assembly designed to produce a narrow beam of electrons. 1957R. W. G. Hunt Reprod. Colour iii. 31 Three electron guns are used in the [mosaic colour television] tube and they fire from the three positions R, G and B.
1931Physical Rev. 1 Aug. 585 (heading) Electron lenses. 1960Gloss. Terms Telecommunic. (B.S.I.) 61 Electron lens, a device producing a system of electric and/or magnetic fields capable of controlling the convergence or divergence of a beam of electrons or ions.
1943Jrnl. Amer. Med. Assoc. 16 Oct. 400/2 Figure 1 shows an electronmicrogram (1 × 14,500) of a sample of purified SK murine virus.
1934Sci. Abstr. A. XXXVII. 203 The electron micrographs, taken with a kathode temperature of 1000° C., showed the crystalline surface structure of the nickel. 1956Sci. News XXXIX. 114 Electron micrographs..showed the partial splitting of nucleic acid and protein [from tobacco mosaic virus]. 1959New Biol. XXX. 61 Electron micrographs can now be made of sections of cells in much the same way as light micrographs were previously made and the result looks more familiar although larger and sharper in detail.
1944Jrnl. Biol. Chem. CLVI. 598 The difference probably was related to the measurement of the images irrespective of orientation on the electron micrographic plates.
1941Amer. Jrnl. Path. XVII. 576 (heading) The electron micrography of purified viruses.
1932Brit. Chem. Abstr. A. 209/1 (title) Electron microscope. 1941Ann. Reg. 1940 345 An important advance during the year was the construction of an electron microscope with about twenty times the resolving power of the best light microscope with oil immersion. 1955Bull. Atomic Sci. Mar. 75/1 The electron microscope..permitted us to observe objects measured in hundred thousandths of a millimeter. 1968Times 13 Nov. 16/1 Scanning electron microscopes..have a much greater depth of focus than electron microscopes have.
1933Chem. Abstr. XXVII. 5631 (heading) Electron microscopic images from secondary electrons. 1961Lancet 12 Aug. 380/2 Electron-microscopic appearances in pinocytosis.
1945Jrnl. Appl. Physics XVI. 731/2 Thin replicas suitable for electron microscopical studies.
1948Ibid. XIX. 119 (heading) The training of technical electron microscopists. 1960New Biol. XXXI. 30 A complicated intracellular system of double membranes..which is known to the electron-microscopists as the ‘endoplasmic reticulum’.
1934Nature 16 June 911/2 It seems that the osmium impregnation method can be applied..to electron microscopy. 1946Nature 14 Sept. 363/2 The size and approximate shape of bacteriophage particles has been investigated by electron-microscopy.
1940Chambers's Techn. Dict. 289/1 Electron multiplier. 1953Amos & Birkinshaw Television Engin. I. v. 107 If the return beam is directed into an electron multiplier the tube output can be increased until it is well above the noise level of conventional vision-frequency amplifiers. 1955Gloss. Terms Radiology (B.S.I.) 22 Electron multiplier, a device, generally in the form of a vacuum tube..in which small electron currents are amplified in several stages by a cascade process employing secondary emission.
1933Sci. Abstr. A. XXXVI. 199 A combined electric and magnetic deflection method which gives electron-optical enlargements of emitting surfaces. 1951Engineering 13 July 40/2 A tube with sufficiently good electron-optical focus for high-definition pictures was made.
1916Chem. Abstr. 299 Electron optics of the hydrogen molecule. 1932Sci. Abstr. A. XXXV. 645 Application of geometric electron optics makes it possible to explain the behaviour of the beam in an electron tube. 1938Nature (Suppl.) 20 Aug. 331/1 A system of ‘electron optics’ has been elaborated which shows how a beam of cathode rays issuing from a point can be reassembled into an image by passing through a localized electrostatic or magnetic field having axial symmetry.
1934Webster, Electron pair, a group of two electrons, as called for in certain atomic theories. If the pair acts as a bond between atoms, it is called a sharing pair, otherwise a lone pair. 1940Chambers's Techn. Dict. 289/1 Electron pair (equated with duplet). 1955Gloss. Terms Radiology (B.S.I.) 15 Electron pair, an electron and a positron arising from pair production. 1955H. B. G. Casimir in W. Pauli Niels Bohr 131 There does not seem any possibility to reconcile the idea of electron pairs with the thermodynamics of superconductors. 1958O. R. Frisch Nuclear Handbk. viii. 12 Electron pairs can be created by other processes including: (a) Passage of a heavy particle through matter..(b) Passage of a fast electron through the field of a nucleus..(c) Collision between two electrons. 1964J. W. Linnett Electronic Struct. Molecules ii. 28 This difficulty of solving the Schrödinger equation for systems containing two or more electrons means that the development of the electron-pair bond has to be based, to a large extent, on empirical reasoning.
[1926Nature 20 Feb. 264/2 The dotted lines represent the position of the energy levels to be expected in the absence of the spin of the electron.] 1930Ruark & Urey Atoms, Molecules & Quanta iii. 96 It is not surprising that the discovery of the electron spin was delayed until 1926. 1941Mind L. 279 Although we cannot pretend to describe the nature of electron-spin as an activity or a condition in the external world, we may say this much about it: spins can be differentiated from one another by specifying their components in a set of mutually orthogonal planes. 1952Physical Rev. 15 Nov. 951/1 We have observed conduction electron spin resonance absorption in fine particles of metallic sodium..at a frequency of 9240 Mc/sec. 1955[see ESR s.v. E III].
1972R. A. Jackson Mechanism iv. 61 Electron spin resonance spectroscopy, which is very sensitive and will detect radical concentrations down to about 10-9m, is extremely useful. 1978Jrnl. R. Soc. Arts CXXVI. 660/1 There were also groups dealing with thermochemistry, crystallography and x-ray diffraction, and with newer techniques involving physical properties such as electron spin resonance.
1948Jrnl. Brit. Interplan. Soc. Nov. 250 The ‘electron telescope’ has been used to make visible stars which could not otherwise be detected.
1923Chem. Abstr. 2801 The positive pole and the auxiliary positive plate in an electron tube consist of a hollow tube and a spiral. 1930Electronics Apr. 25/2 The electron-tube control of the stage lighting in the..Chicago Civic Opera House. 1932Iron & Steel Engineer Mar. 124 (title) The application of electron tubes in the steel industry.
1930Rutherford et al. Radiations from Radioactive Subst. xvii. 530 In dealing with the changes of energy in atomic nuclei, it is convenient to express the energy in terms of the kinetic energy gained by an electron..in volts. The energy per atom associated with a change of mass 1 on the atomic mass scale can be shown to be 933 million electron volts. 1938R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity (ed. 2) iii. 48 Energies of less than 100 e.V. 1962Gloss. Terms Nuclear Sci. (B.S.I.) 41 Electronvolt, a unit of energy (abbreviation: eV) equal to the kinetic energy acquired by an electron when accelerated through a potential difference of one volt (1 eV = 1·60 × 10-12erg).
1927Proc. Nat. Acad. Sci. XIII. 460 A single plane of atoms reflects a very appreciable fraction of the electron wave, whereas the same plane would reflect only an inappreciable part of an X-ray wave. 1930G. P. Thomson Wave Mechanics of Free Electrons ii. 36 On de Broglieo's theory the space round a nucleus has a refraction index for electron waves which varies with the distance from the nucleus. 1942J. D. Stranathan Particles Mod. Physics xiv. 540 These electron waves travel with a velocity greater than that of light. |