| 释义 |
▪ I. duplex, a.|ˈdjuːplɛks|
[a. L. duplex twofold, f. duo two + plic- to fold. Not in Webster 1828.]
1. a. Composed of two parts or elements; twofold.
1817T. L. Peacock Melincourt II. 51 A poet and a critic—in which duplex capacity he had first deluged the world with torrents of execrable verses—and then written anonymous criticisms to prove them divine. 1841Miall in Nonconf. I. 29 A double definition is required; because we are endeavouring to express a duplex idea. 1877Tyndall in Daily News 2 Oct. 2/4 Social progress is for the most part typified by this duplex or polar action.
b. In various technical applications.
duplex escapement, one in which the escape-wheel has both spur and crown teeth; duplex gas-burner, one having two jets so arranged as to combine the two flames into one; duplex lamp, one with two wicks; duplex lathe, one having a cutting-tool at the back opposite to that in front, and in an inverted position; duplex process, a process for making steel in which the charge undergoes treatment by two of the standard processes or in two furnaces in succession.
1851Offic. Catal. Gt. Exhib. III. 1266 Gold hunting watch..style of regulator with duplex escapement. 1883M. E. Braddon Gold. Calf xxv. 281 In the mellow light of a duplex lamp. 1889Findlay Eng. Railway 114 A duplex steam hammer of 30 tons, and one of 10 tons. 1902Jrnl. Iron & Steel Inst. LXI. 589 The quantities of slag made were also very great..compared with 0·1 ton of slag in the present duplex process. 1926Ibid. CXIII. 571 This is a continuous duplex process carried out in two tilting open-hearth furnaces. 1939J. Dearden Iron & Steel Today vii. 101 Duplex processes..are designed to combine the advantages of the Bessemer and open-hearth processes, while avoiding their disadvantages. 1951G. R. Bashforth Manuf. Iron & Steel II. xii. 353 Duplex processes usually employ a high percentage of hot metal.
c. Designating paper or board which is formed by uniting two separate layers of paper, or which is coloured differently on either side.
1901Brit. Pat. 22,418 2 In making duplex papers that is papers that may be white on the one side and coloured on the other, or be coloured on one side and coloured with a different colour on the other side, a brass or metal roller D would be used for spreading the colour. 1914E. A. Dawe Paper xvii. 120 Duplex Papers may be made of two layers of differently coloured papers brought together in the wet state and rolled together, or may be coated with different colours, after the paper is made, as duplex art papers. 1962F. T. Day Introd. to Paper iv. 46 In the case of Duplex tinted boards, different coloured pulps are used to produce a board with a different colour on each side.
d. Of an eye: having pigment on the anterior surface of the iris as well as on the posterior surface, as in eyes that are a colour other than blue.
1908C. C. Hurst in Proc. R. Soc. B. LXXX. 86 The eyes in which two kinds of pigment are present; the one, yellow-brown in colour, deposited on the outer or anterior surface of the iris; the other, blue-black in colour, deposited on the inner or posterior surface of the iris. Such eyes I propose to call duplex. Ibid., To the duplex type belong the various shades of eyes with both anterior and posterior pigments. 1911A. D. Darbishire Breeding & Mendelian Discov. 276 Duplex eyes are those which have a layer of brown pigment in front of the iris. 1946R. R. Gates Human Genetics I. v. 88 Hurst..classified eyes as duplex or simplex.
e. Biol. Of a polyploid organism: having the dominant allele of any particular gene represented twice.
1923A. F. Blakeslee et al. in Bot. Gaz. LXXVI. 345 The convenient terms nulliplex, simplex, duplex, triplex, and quadriplex, can be used in regard to the number of chromosomes containing a given gene, without thereby admitting the amount of so-called dominance of the factors in question. 1963Lewis & John Chromosome Marker iv. iii. 327 Thus, a tetraploid of the type AAaa (duplex) can produce gametes of three kinds—AA, Aa and aa.
f. Biochem. Applied to a molecular structure, or part of one, in which two polynucleotide strands are linked together side by side, as in a DNA molecule.
1969Nature 22 Nov. 771/1 There should be a unique sequence of complementary material in each strand giving rise to a single, homogeneous set of duplex regions in the heteroduplex molecules. 1970Proc. Nat. Acad. Sci. LXVI. 197 It was predictable that the flow of biological information in the living cell, postulated to start with the transcription of the duplex DNA to yield a series of messenger RNA species, must originate from only one of the two complementary DNA strands. 1971Nature 19 Feb. 530/1 The enzyme shows a strong preference for single stranded DNA, which it degrades about 150 times faster than duplex DNA.
2. Electric Telegraphy.
a. Applied to any system by which two messages can be sent along the same wire at the same time: now called diode.
b. Now restricted to systems in which two messages are sent simultaneously in opposite directions: opp. to diplex, q.v.
1873Telegraphic Jrnl. I. 59 The term duplex telegraphy has recently been applied to the system by which two messages may be sent along the same wire at the same time. 1879G. B. Prescott Sp. Telephone p. iii, In 1872 Stearns perfected a duplex system, whereby two communications could be simultaneously transmitted over one wire.
▪ II. ˈduplex, v. Electric Telegraphy.
[f. prec. 2]
trans. To render duplex; to arrange (a wire or cable) so that two messages can be sent along it at the same time.
1880Daily News 27 Dec. 3/4 The Duplexing of Submarine Cables. 1882Sat. Rev. 18 Mar. 330/2 Duplexing had been known and used on land lines for some time before it could be applied to long deep-sea cables. 1883Daily News 30 May 7/3 Science had enabled them to duplex their cables. 1894Times 30 Apr. 3/4 There are two systems of duplexing—the one called the ‘differential’, where you balance two currents against one another, and the ‘bridge’ system, where you balance two electric pressures or tendencies to drive a current.
▪ III. duplex, n.|ˈdjuːplɛks|
[f. the adj.]
1. orig. U.S. A house or other building so divided that it forms two dwelling-places; also, a flat occupying two floors. Also attrib. or as adj.
1922Daily Ardmoreite (Ardmore, Okla.) 6 Jan. 9/1 For Rent—6 room duplex bungalow. 1931‘D. Stiff’ Milk & Honey Route iii. 32 You live in a duplex with ten baths, or a cold-water walk-up flat, according to your ability to pay rent. 1936Archit. Rev. LXXX. 101 It consists of an office for the architect-owner on the ground floor, and on the upper floors two ‘duplex’ (i.e. self-contained two-storey) apartments, one of which is occupied by the architect. 1937Sunday Dispatch 28 Feb. 2/7 A duplex is a house of two storeys, with its own front door on the ground floor. 1938Archit. Rev. LXXXIV. 165 (caption) Duplex (two-storey) flats occupy the centre portion. 1959Observer 15 Nov. 18/3 We do not live in a spacious house..but a Chelsea duplex. 1968Globe & Mail (Toronto) 17 Feb. 49/1 (Advt.), 3 bedroom duplex or equivalent. 1969Sydney Morning Herald 24 May 37/1 (Advt.), The owner has had plans drawn for a very impressive duplex. 1971Rand Daily Mail (Home Owner) 27 Mar. 7/2 City dwellers are gravitating towards high density living (flat complexes, town houses, duplex..and so on).
2. Biochem. A double-stranded or duplex polynucleotide molecule (see duplex a. 1 f).
1963Proc. Nat. Acad. Sci. L. 910 No evidence for an RNA-replicating duplex, analogous to that of the single-stranded DNA virus ϕΧ174, has thus far appeared, despite the fact that RNA-RNA duplexes are known to be very stable structures. 1967I. H. Herskowitz Basic Princ. Molec. Genetics iii. 31 Hybrid DNA-RNA duplexes (each composed of one DNA strand and one RNA strand) can be made. 1969Prog. Nucleic Acid Res. IX. 304 The stability of the duplex is affected both by the base composition and by the sequences of bases along the individual strands. |
