| 释义 |
▪ I. null, n.1
[a. F. nulle, It. nulla, fem. of F. nul, It. nullo: see null a. So G. null(e, † nulla, Sw. nolla; G. null, Du., Da. nul, Sw. nol.]
a. A cipher; a nought.
1605Bacon Adv. Learn. ii. xvi. §6 The kinds of Cyphars (besides the simple cyphars with Changes, and intermixtures of Nulles and Nonsignificants) are many. a1626― War with Spain (1629) 5 If part of the People or Estate be somewhat in the Election, you cannot make them Nulls or Cyphers in the..Translation. 1691T. H[ale] Acc. New Invent. p. ix, An Unite was too much, and a Null too little.
b. Cryptography. (See quot. 1961.)
1915J. Buchan 39 Steps iii. 72 It was a numerical cypher, and by an elaborate system of experiments I had pretty well discovered what were the nulls and stops. 1961Shulman & Weintraub Gloss. Cryptography, Null cipher, a form of concealment in which most of the letters used in a text are nulls. Nulls, meaningless letters or numbers used in cryptograms for various purposes. 1968‘S. Jay’ Sleepers can Kill iv. 47 A very simple cypher, Mr. Connor, but it can of course be broken by frequency analysis... Don't forget to reverse and arrange in five letter groups, of course, with nulls to make the numbers up. 1972Sci. Amer. Nov. 114/2 If this is intercepted and a translation demanded of the sender, he strikes out the symbols of the true text, explaining that they are what cryptographers today call ‘nulls’, meaningless symbols inserted only to make the cipher harder to break.
c. Linguistics. (See quots.)
The attrib. example properly belongs in sense 4 of the adj.
1964E. Bach Introd. Transformational Gram. v. 110 Since Y and Z (as usual) include the possibility of null, the transformation will have the desired effect of producing all permutations of the terminal elements. 1968Amer. Speech XLIII. 277 In treating few in ‘few people’ and much in ‘much money’ as pre-article forms, Roberts assumes the existence of an unarticulated determiner he calls null. 1968R. T. Harms Introd. Phonological Theory v. 44 If two obstruents occur initially, the first one is deleted. (Instead of ‘null’, the symbol ‘ø’ is sometimes used.) 1972R. A. Palmatier Gloss. Eng. Transformational Gram. 111 Null, lacking status as a morpheme or formative—that is, having no overt representation on any level of the grammar... Null string, an empty string—that is, no string at all.
▪ II. null n.2
variant of knurr.
1816Sporting Mag. XLVIII. 178 The games most common at Newmarket were fives, spell and null, marbles [and] chuck-farthing.
▪ III. null n.3
variant of knurl n. 1.
1875Knight Dict. Mech. 1535/2 By moving the lever up and down, the carriage is..advanced the proper distance and the nulls or beads formed by the cutter.
▪ IV. null, a.|nʌl|
Also nul.
[a. OF. nul masc., nulle fem., = It. nullo, nulla, Sp. nulo, nula, or ad. L. nullus, f. ne not + ullus any. So G. null, Du. nul.]
1. a. Void, of no legal or binding force; of no efficacy, invalid.
1563–7Buchanan Reform. St. Andros Vernac. Writ. (S.T.S.) 16 Al thayr votis that tendis to continuation, to be nul. 1569Reg. Privy Council Scot. II. 7 In caise the same titillis of the law be reduceable or may be declarit null. 1639Sir T. Stafford in Lismore Papers Ser. ii. (1888) IV. 66 There Late assemblie to be held null, the Kinge to appoint a new one. 1657W. Morice Coena quasi κοινὴ §23. 231 To say expressly that all is Null which was done at Pyworthy. 1714R. Fiddes Pract. Disc. ii. 35 Their commands are originally null and of no force. 1765Blackstone Comm. I. xv. 425 If such consent from the father was wanting, the marriage was null. 1849Macaulay Hist. Eng. v. I. 582 The act of attainder..would become superfluous at the very moment at which it ceased to be null. 1888Bryce Amer. Commonw. I. xxxiv. 524 The tribunal is disposed rather to support than to treat as null the act done.
b. In phrase null and void.
1669Marvell Corr. Wks. (Grosart) II. 297 Prorogation makes all Bills, Votes, and Proceedings of this Session null and voyd. 1769Junius Lett. xvi. (1788) 95 Any votes given to him are null and void. 1803Wellington in Gurw. Desp. (1835) II. 610, I yesterday gave notice..that I should consider it null and void from the 27th instant. 1871Freeman Norm. Conq. (1876) IV. xvii. 27 That all acts done by the authority of the usurper Harold were held to be null and void.
2. a. Of no value or importance; insignificant, ineffective.
1790Burke French Rev. Sel. Wks. II. 208 Here the principle of contribution..is reprobated as null, and destructive to equality. 1803Malthus Popul. (1817) III. 185 We take all possible pains to weaken and render null the ties of nature. 1842Kingsley Lett. (1878) I. 79 Truth made practically null by modifying it to suit circumstances. 1880Kinglake Crimea VI. ix. 304 Upon grounds thus weak, or, to speak more exactly, thus null he founded his charges.
b. Devoid of character, expression, or distinctive personality.
a1850Marg. Fuller At Home & Abroad (1860) 343 As to character, so null that everybody laughed. 1855Tennyson Maud i. ii. 6 Faultily faultless, icily regular, splendidly null. 1889H. F. Wood Englishman Rue Caïn i, The ordeal of lighting up that terribly null countenance.
3. Nothing; nil; non-existent.
1761Phil. Trans. LII. 277 The effect of the other planets is either null or known. 1792Ibid. LXXXII. 242 Atmospheric electricity has been..variable..; sometimes quite null, then weak, or strong by turns. 1811Pinkerton Petral. II. 486 Its influence on that element was absolutely null. 1834McMurtrie Cuvier's Anim. Kingd. 384 The internal lobe of the maxillæ null or very small. 1866R. M. Ferguson Electr. (1870) 15 The combined effect of the two terrestrial poles..is thus null.
4. a. spec. in null belt, null method, null point (see quots.). Also more widely, esp. in Math., with the sense: having, being, or associated with the value zero. null space, a space composed of all quantities that are transformed into zero by some given transformation.
1809–10Coleridge Friend (1818) III. 150 That confusion and formality are but the opposite poles of the same null⁓point? 1835W. R. Hamilton Conjugate Functions 23 The transition may be said to be null, or a null step, as producing no real alteration in the moment from which it is made. Ibid. 31 The standard or zero-moment a itself may be denoted by the complex symbol 0 + a, because it may be conceived as generated from itself by applying the null step 0. Ibid. 35 The null cardinal (or number none). 1851Nichol Archit. Heav. (ed. 9) 208 The centre of gravity and motion, being the mere point where all opposite tendencies find their balance—the system's null point. 1860Maury Phys. Geogr. xv. §640 This calm zone..may be considered as a thermal adjustment—the dynamical null-belt—between the trade-winds of the two hemispheres. 1873Maxwell Electr. & Magn. (1881) I. 301 Methods of this kind, in which the thing to be observed is the non-existence of some phenomenon, are called null or zero methods. 1884A. Buchheim in Phil. Mag. XVIII. 459 A linear space of (α-1) dimensions will be called an α-point... A matrix A of order n is considered as operating on the coordinates of the points of an n-point... If A is of nullity α, the equation A(xl{ddd}xn) = 0 is satisfied by all the points of a certain α-point, and conversely. I call this α-point the null space of A. 1885Proc. London Math. Soc. XVI. 78 A point x, such that ϕx = 0, is called a null-point of [the matrix] ϕ. 1898A. N. Whitehead Universal Algebra I. ii. iii. 25 Since in combination with any other element the null element 0 disappears, the symbolism may be rendered more convenient by writing - a for 0 - a. 1922E. H. Neville Prolegomena to Analytical Geom. v. v. 303 An ordinary circle of radius zero is called a nul circle. 1926H. Bagchi Course of Geom. Anal. v. 263 The theorem..prescribes a null value for a determinant having two coincident rows or columns. 1930J. W. Young Projective Geom. ix. 158 If A and B coincide, the vector AB is called the null vector and is denoted by 0. 1941Birkhoff & MacLane Surv. Mod. Algebra x. 268 The null-space of a linear transformation T is the set of all vectors ξ such that ξT = O. The null-space of a matrix A is the set of all row matrices X which satisfy the homogeneous linear equations XA = O. 1954H. Griffin Elem. Theory of Numbers i. 8 A null element is an integer that divides only itself. Ibid., Zero is the null element of the rational integers. 1956R. H. Atkin Math. & Wave Mech. iii. 76 As in all algebras we find it convenient to introduce two identity operators. These are called the unit operator (idem factor) and the nul operator (zero). 1961Seifert & Brown Ballistic Missile & Space Vehicle Systems xvii. 404 They [sc. gyroscopes]..operate as angular error detectors over a very small range around their reference or null positions. 1962C. Wexler Analytic Geom. v. 141 The plane cuts the cone merely in a point (the vertex), resulting in a null circle or a null ellipse. 1964E. Bach Introd. Transformational Gram. ii. 14 Among the elements assumed to be available for each grammar..there is one which plays a special role, namely, the null (unit or identity) element. It functions in the mathematical system underlying the representations of a grammatical theory as does zero in ordinary addition, or the digit 1 in ordinary multiplication. 1971L. T. Agger Introd. Electricity xviii. 326 Balance occurs with null, or zero, deflection of the pointer. 1971C. W. Curtis in Powell & Higman Finite Simple Groups iii. 171 f vanishes on the nullspace of α. 1971J. Z. Young Introd. Study Man xvi. 201 This ingeniously establishes the change in growth power by a nul method.
b. Mech. and Geom. null point [tr. G. nullpunkt (A. F. Möbius Lehrb. d. Statik (1837) I. vi. 144)], the point of intersection of all the null lines of a given wrench that lie in a given plane; null line, a line about which the moment of a given wrench is zero; null plane [tr. G. nullebene (A. F. Möbius, loc. cit.)], the plane containing all the null lines of a given wrench that pass through a given point; null system, a system of null points and their corresponding null planes.
1903C. M. Jessop Treat. Line Complex iii. 45 The distinction between the two spaces σ and σ′ has now disappeared and we have a (1, 1) correspondence between the points and planes of space in which each point lies in its corresponding plane... Such a correspondence is called a null-system. The corresponding points and planes are called ‘null-points’ and ‘null-planes’. 1911Encycl. Brit. XVII. 967/1 In the ‘Null-System’ of A. F. Möbius (1790–1868), a line such that the moment of a given wrench about it is zero is called a null-line. 1942Synge & Griffith Princ. Mech. x. 301 A rigid body is acted on by a force F at O and a couple G. P is an assigned point, with position vector r relative to O. Show that there is a single infinity of lines through P about which the force system has no moment; show that these lines lie in a plane... (The lines are called null lines, and the plane a null plane.) 1964C. E. Springer Geom. & Anal. Projective Spaces x. 273 In a polar correlation with a skew-symmetric matrix, every point is incident with its corresponding plane. This type of correlation is called a null system, a designation used in the theory of statics as developed by Möbius.
c. Math. and Logic. Of a class or set: having no members. Of a propositional function or relation: always false; having the null class as its range.
1903B. Russell Princ. Math. ii. 22 A propositional function is said to be null when it is false for all values of x; and the class of x's satisfying the function is called the null-class, being in fact a class of no terms. 1906W. H. & G. C. Young Theory of Sets of Points 288 The null-set..contains no point. 1932Lewis & Langford Symbolic Logic vii. 208 The universal function is expressible as p v ∼ p. The null-function is the negative of this. 1941O. Helmer tr. Tarski's Introd. Logic v. 90 We have..in the calculus of relations two special relations, the universal relation {logicor} and the null relation {logicand}, the first of which holds between any two individuals, and the second between none. 1948Ambrose & Lazerowitz Fund. Symbolic Logic x. 215 To say that a class is null, or empty, is the same as saying that there are no values satisfying its defining function. 1955[see domain n. 4 f]. 1956A. Church Introd. Math. Logic (rev. ed.) I. 31 If the range is given,..there is only one null class. But, e.g., the range of the null class associated with the form sin x = 2 and the range of the null class associated with the form {elem} ‹ 0 are not the same... We shall speak respectively of the ‘null class of real numbers’ and of the ‘null class of positive real numbers’. 1966S. Beer Decision & Control vi. 107 This does not matter; it simply means that the complementary set has no elements—and this is called a null set.
d. Physics. Existing between or joining points in space-time between which the interval is zero; null cone = light cone s.v. light n. 16.
1928Phil. Mag. V. 242 A null-surface is defined as an envelope of null-cones,..while the characteristic lines on a null-surface prove to be geodesic null-lines. Ibid., The history of a light wave in space-time is a null-surface. 1942Synge & Griffith Princ. Mech. xvi. 475 A null line represents the history of a flash of light traveling along the axis Ox of a Galilean frame. 1959J. Aharoni Special Theory of Relativity i. 25 An interval ds between two events can be either real, zero, or imaginary... In the first case the interval is called space-like, in the second case a null-interval, and in the third case time-like. 1968T. C. Bradbury Theoret. Mech. xiii. 589 If the four-vector joins O and C, then r2 - c2t2 = r′2 - c2t′2 = 0. Such a vector is a null vector. Events separated by null vectors can be joined by light signals; in fact, the light cone is frequently called the null cone. 1972J. Ehlers et al. in L. O'Raifeartaigh Gen. Relativity iv. 75 In a normal hyperbolic Riemannian manifold, the distinction between the interior and exterior of the null cone Np of a point p can locally be defined by means of the sign of the world function Ω(p, q), for q near p.
e. Statistics. null hypothesis, a hypothesis that is the subject of a significance test, esp. the hypothesis that there is no difference between specified populations (any apparent difference being due to sampling or experimental error).
1935R. A. Fisher Design of Experiments ii. 19 The two clases of results which are distinguished by our test of significance are..those which show a significant discrepancy from a certain hypothesis; namely, in this case, the hypothesis that the judgements given are in no way influenced by the order in which the ingredients have been added; and..results which show no significant discrepancy from this hypothesis. This hypothesis..is again characteristic of all experimentation... We may speak of this hypothesis as the ‘null hypothesis’, and it should be noted that the null hypothesis is never proved or established, but is possibly disproved, in the course of experimentation. 1973Jrnl. Genetic Psychol. CXXIII. 86 The specific null hypotheses tested were as follows: 1. There were no differences in hostile press (fear of failure) score decreases between self-reinforcement, group therapy, and control groups. 2. Hostile press scores do not decrease significantly during the self-reinforcement condition. [Etc.] 1975Nature 20 Feb. 607/1 The evidence..for positive selection directing the evolution of early vertebrate haemoglobin is supported by a χ2 test, performed to test the null hypothesis that sites where mutations produced acquired crucial functions did not evolve at a different rate from all other sites.
5. Passing into n.: A condition of no signal; also, a direction in which no radiation is detected or emitted. Freq. attrib.
1926Bell Syst. Techn. Jrnl. V. 295 The number of lobes is, of course, equal to the number of null directions. 1931Proc. IRE XXXI. 1426 The nulls and maxima..have been plotted in Fig. 16 for an element length of four wavelengths. Ibid. 1427 Figs. 15 and 16..give the null points. These are seen to be 0, 30, and 90 degrees in Fig. 15. 1931Moyer & Wostrel Radio Handbk. xii. 601 A direct-current galvanometer, protected by a suitable shunt, is used as a null indicator. 1958Condon & Odishaw Handbk. Physics iv. v. 66/2 Null determinations in d-c measurements are almost invariably made with a D'Arsonval-type galvanometer. 1962Newnes Conc. Encycl. Electr. Engin. 94/2 The precision of a bridge measurement depends on the sensitivity of the null detector. 1968M. Woodhouse Rock Baby xv. 150, I set up the loop of the D.F. set and plugged in the headset. When the signal came..I got a clear null a little west of due south. 1973J. Hulbert All About Navigating vii. 96 It is much easier to pick out the softest point than the loudest point and so a null is used for direction finding. 1975Gramophone Oct. 734/3 The many nulls and lobes beyond these angles are not too important, and are due to the interaction of the radiator with its housing and the corners of the cabinet.
▪ V. null, v.1|nʌl|
[f. null a., after annul. Cf. also OF. nuller, med.L. nullare (rare).]
†1. trans. To negative; to make negative. Obs.
c1620A. Hume Brit. Tongue (1865) 33 Not is an adverb,..and in our tong followes the verb that it nulleth.
†2.
a. To reduce to nothing; to destroy or efface completely. Obs. (freq. in 17th c.)
c1645Howell Lett. (1650) I. 384, I believe [not]..that she was able to null and extinguish the native languages she found in those places. a1691Boyle Hist. Air (1692) 69 These objections..do not really null or take away the possibility of the thing. 1702S. Parker tr. Cicero De Finibus v. 356 In a manner to null and erase their very Being. 1722De Foe Col. Jack (1840) 342 He does all he can to null or quash the story.
†b. To deny the validity of. Obs. rare—1.
1656Baxter Reformed Partn. 338, I speak not this against any Bishops that acknowledge the Presbyters to be true Pastors..but of them that null the Presbyters office.
3. To annul, cancel, make void. Also with out.
1643Richlieu's Epit. in Harl. Misc. (Malh.) V. 333 Lest he should spare her, when she was dead, he nulled her last will. 1663–4Marvell Corr. Wks. (Grosart) II. 139 They affirm that his.. Royal majesty..desired that the Privileges might be nulled. 1693Norris Pract. Disc. (1711) III. 90 God forbid that such a Law should ever be null'd or made void. a1716Bp. O. Blackall Wks. (1723) I. 294 Because these Marriages had been made before the Law against them was given,..it was not reasonable that they would be nulled. 1757Burke Abridgm. Eng. Hist. Wks. 1842 II. 584 The first election he nulled, because its irregularity was glaring. 1869Doran Table Traits 384 A particular act of their worships..nulled the proclamation. 1957Electronics 1 Mar. 163 The receiver uses a shielded-loop antenna to null out main powerline noise. Ibid., The atmospherics..are greater in amplitude than most of the peaks of the background hash after nulling the main source of powerline noise. 1971Sci. Amer. Aug. 65/2 The harmonic signal is electronically processed and sent through the feedback winding to ‘null out’, or cancel, the ambient field within the sensor.
Hence ˈnulling vbl. n.
1654H. L'Estrange Chas. I (1655) 78 The unbilleting of Souldiers and nulling of Martiall Law in times of Peace. a1687H. More Cont. Remark. Stories 446 Which is a perfect dissolution or nulling of the True..Religion.
▪ VI. null, v.2
[var. of nurl, knurl v.]
intr. a. To make knurls. Hence ˈnulling vbl. n., the making of knurls; knurled work. b. Of a line: To kink.
1851C. Cist Sk. Cincinnati xiii. 245 All kinds of turning used by cabinet makers, including nulling of every pattern, furnished at the shortest notice. 1890in Cent. Dict. 1914Eberlein & McClure Pract. Bk. Period Furnit. 63 Nulling, made up chiefly of beading, cabling and hollows, is often used to ornament the bulbous legs of Jacobean furniture. 1934J. Gloag Eng. Furnit. v. 86 The edges of tables and desks were scalloped with nulling, heavily gilded. 1936C. H. Hayward Eng. Period Furnit. ii. 33 The carved flutes partly filled with nullings are a feature that was used considerably in Elizabethan times. 1966M. M. Pegler Dict. Interior Design 307 Nulling, a Jacobean wood-carving technique which produced an effect similar to repoussé or chased metalwork. The patterns were created by a series of small projections or recessions from the surface (like a boss or bead) of the wood. |