| 释义 |
lambda|ˈlæmdə|
Also 7 lamda.
[Gr. λάµβδα (or λάβδα).]
1. The 11th letter of the Greek alphabet, λ, λ.
c1400Mandeville (1839) iii. 20 Thei clepen hem..α Alpha..κ Kappa, λ Lambda. 1603Holland Plutarch's Mor. 1324 Whether in the Future tense it [the verb βάλλω] should lose one of the two Lamdaes? 1799Kirwan Geol. Ess. 285 The calcareous mountains of Savoy are often arched like a lambda.
2. Anat. ‘The point of junction of the sagittal and lambdoidal sutures’ (Syd. Soc. Lex. 1888).[c1400Lanfranc's Cirurg. 109 A boon þe which is clepid alauda. (The Latin has: ad modum literæ laudæ grecæ.)] 3. lambda moth, a moth so called from a mark on its wings, resembling the letter (Webster 1890).
1798Nemnich Polyglot Lex. Nat. Hist., Eng., Lambda moth, Phalaena gamma.
4. Physics. lambda point, the temperature (approximately 2·18°K) below which liquid helium in equilibrium with its vapour exhibits superfluidity, and at which there is a sharp maximum and apparent discontinuity in its specific heat; transf., any temperature at which the specific heat of a substance exhibits similar behaviour, increasing at an increasing rate as the temperature is raised to this value and then dropping abruptly; hence lambda curve, lambda line (on a phase diagram), lambda transition. Freq. written as λ point, etc.
1932W. H. & A. P. Keesom in Proc. Sect. Sci. Kon. Akad. Wetensch. Amsterdam XXXV. 742 The specific heat of liquid helium at about 2·19°K falls from a value of 3·0 to a value of about 1·1 certainly within 0·02 degree... For convenience sake it is desirable to introduce a name for the point at which this jump occurs. According to a suggestion made by Prof. Ehrenfest we propose to call that point, considering the resemblance of the specific heat curve with the Greek letter λ, the lambda-point. 1933W. H. Keesom in Ibid. XXXVI. 149 It is in this sense that..we speak of the lambda-point..and of the lambda-curve. 1940Physical Rev. LVII. 417 Measurements of the temperature variation of the adiabatic and isothermal Young's and rigidity moduli and of the coefficient of thermal expansion of pressed specimens of ammonium chloride in the neighbourhood of the λ-point transition at 242·8°K are reported. 1952J. F. Allen in F. E. Simon et al. Low Temperature Physics iii. 73 The phase diagram of liquid helium..is crossed by a line which has been called the λ-line. 1958Condon & Odishaw Handbk. Physics v. xi. 159/2 The λ transition involves no detectable change in spatial structure. 1964Physical Rev. CXXXV. A1696/1 One would expect that the elastic properties of β brass near its lambda point should strongly resemble those of other solids which undergo cooperative order–disorder transitions. 1966K. Mendelssohn Quest for Absolute Zero x. 234 The characteristic feature of superflow..was transport completely free of friction, taking place at a ‘critical velocity’ which only depended on temperature and vanished at the lambda-point.
5. a. Chem. A millionth of a litre; usu. denoted by λ.
1934P. L. Kirk in Mikrochemie XIV. 13 It seems logical to use the designations mm3 = µ l = λ. Such a procedure could simplify discussion considerably if the letter lambda were used with this significance, and we shall in future adhere to this usage. Ibid., Since 1 l. of normal solution contains 1 equivalent..1 λ contains 1 micro⁓equivalent. 1939Mikrochemie XXVI. 32 All the drops should have the same volume, 1 λ. 1939E. J. Conway Micro-diffusion Anal. i. 4 For the actual designation of the minute quantities or volumes..we have the milligramme (mg.), and the gamma (γ or 0·001 mg.), also termed the microgramme (µg) and the lambda (λ or 0·001 ml.—introduced by Kirk). 1961A. Steyermark Quantitative Org. Microanalysis (ed. 2) i. 2 The terms gamma (γ), and lambda (λ) are to be substituted with microgram (µg.) and microliter (µl.) respectively. 1974Nature 15 Nov. p. xi (Advt.), Corning disposable micro-sampling pipettes are made from ‘Pyrex’ brand borosilicate glass... The accuracy of the graduated 5 Lambda (λ) is {pm}1%.
b. Nuclear Physics. Used, usu. attrib., to denote a neutral hyperon (and its anti-particle) which has a mass 2183 times that of the electron, a spin of ½, and zero isospin, and on decaying usually produces a nucleon and a pion; † orig. applied to other hyperons also. Freq. written as λ.
1954Physical Rev. XCIII. 861/1 We have reported two examples of λ0 particles produced in hydrogen by negative pions (π-) of 1·5-Bev kinetic energy. Ibid., We are using here the nomenclature suggested for V events at the International Congress on Cosmic Radiation, Bagnères-de-Bigorre, France. Accordingly λ0, +, - → nucleon + pion + Qλ. Ibid. XCVI. 543/1 The known hyperons, λ-, Ω-, have masses equivalent to 1200 and 1320 Mev, respectively. 1963Sci. Amer. Jan. 40/2 When a K- -meson struck a proton (p), a small fraction of the collisions produced a neutral lambda particle (λ0) and a negative and a positive pi meson. 1963K. W. Ford World of Elem. Particles vi. 179 The sigma particle lives too short a time to move a measurable distance.., decaying almost at once into a lambda and a photon (σ0 → λ0 + γ). 1968M. S. Livingston Particle Physics iv. 80 This evidence was the observation of V tracks consisting of two charged-particle tracks coming from a common origin, of which one was identified as a proton and the other as a negative pion. The neutral particle which decayed to give these products, now called the lambda-zero, (λ0), must have had a mass greater than the sum of proton and pion masses.
Add:6. Microbiol. A temperate bacteriophage originally isolated from Escherichia coli and much used in genetic research; also denoted by λ. Freq. attrib.
1952J. Lederberg et al. in Cold Spring Harbor Symp. Quant. Biol. XVI. 436/1 The exposure of sensitive cells to suspensions of the free phage, which we named ‘λ’, by analogy to a killer factor in Paramecium, results in the lysis of a variable proportion of cells. 1953Ibid. XVIII. 95/1 Two lambda mutants have been used in our experiments. 1963Jrnl. Bacteriol. LXXXV. 1202 (heading) Mutant of lambda bacteriophage producing a thermolabile endolysin. 1973R. G. Krueger et al. Introd. Microbiol. xiv. 405/1 When bacteriophage λ infects a nonlysogenic host cell, the infection results in lysis in about 70{pcnt} of the cases and lysogeny the other 30{pcnt} of the time. 1976Sci. Amer. Jan. 65/2 The repressor we have studied is a protein molecule manufactured by bacteriophage lambda, a virus that infects the common colon bacterium Escherichia coli. 1983J. R. S. Fincham Genetics xi. 300 Lambda is but one of a large family of closely related phages which..have their genomes integrated into the host DNA in the lysogenic state. |