| 释义 |
▪ I. by-pass, n.|ˈbaɪpɑːs, -æ-|
Also formerly bye-pass.
[f. by- B. 3 b + pass n.]
1. A secondary pipe issuing from the main or service pipe below a stop-tap or cock, allowing the free passage of a small supply of gas, steam, etc., when the main supply is shut off; esp. the small tube and pilot light of a gas-jet, which remains alight when the jet is turned off. Also attrib.
1848W. Pole tr. Alban's Steam Engine 264 It is a sort of by-pass to allow the steam to travel freely from the upper into the lower box. 1876Amer. Gas-L. Jrnl. 3 July 20 (Knight a 1884), Farmer's hydraulic main, with dip-pipe and bye-pass. 1888Morning Post 12 Jan. 2/3 The only service from the stage supply that was open being one half inch bye-pass for the pilot light of auditorium sun burner. 1895Daily News 10 Oct. 6/4 The innovation..consists of a little ‘by-pass’ arrangement by which a tiny flame is always kept going. 1901[see accelerator c]. 1959Times 25 July 9/4 An external by-pass valve.
2. Electr. A circuit or element providing an alternative path for the flow of current. Also attrib.
1914R. A. Philip in H. Pender Amer. Handbk. for Electr. Engineers 364 To avoid the excessively high voltage which would occur when the circuit opened..an automatic by-pass is provided in multiple with the lamps. 1930Engineering 9 May 600/1 The sides of these two switches, which are remote from the transformer, being connected together to form a ‘by-pass’ connection. 1931Answers 10 Oct. 36/2 It might be found advantageous to connect a by-pass condenser across the telephones in the case of short-wave sets. 1964R. F. Ficchi Electrical Interference v. 49 A typical bypass filter made up of a capacitor component.
3. A road diverging from and re-entering a main road, esp. one constructed as an alternative route to relieve congestion of traffic in a town. Also attrib.
1922Daily Mail 2 Dec. 5 New roads and by-passes, which should remove some of these danger spots. 1923Times (Weekly Ed.) 25 Jan., The Kingston by-pass will begin at the Robin Hood gate. 1929Times 13 Nov. 9/4 It was recommended that the proposal to make a by-pass road be dropped. 1937[see by-pass v. 1 b]. 1955Times 13 June 5/3 Before they considered secondary roads..the trust should urge..the completion of the by-passes. 1966J. Betjeman High & Low 70 This had to happen at the corner where the by-pass Comes into Egham out of Staines.
4. transf. and fig.
1928T. E. Lawrence Let. 15 Mar. (1938) 579 They will come to you, round about through the parcel mail... I sent them by an official by-pass, for safety. 1957Listener 18 July 102/3 To overstress Crashaw's capacity for writing hypnotic poetry would be a dangerous simplification, a crude bypass for those who want to dodge the implications of his belief.
5. Aeronaut. Applied to a type of jet engine (see quot. 1955).
1948Jrnl. R. Aeronaut. Soc. LII. 714/1 One stage on towards eliminating the propeller, the ducted fan or ‘by-pass’ engine offers interesting possibilities. 1955Times 26 Aug. 4/5 In a conventional jet engine all the air is compressed and then heated by the injection of burning fuel, expanded through the turbine, and finally ejected at high velocity. In a by-pass engine only a proportion of the air is compressed and heated; the remainder by-passes the combustion system and turbine and rejoins the heated gases in the jet pipe, to mix with them and lower their temperature before the whole mixture is ejected at a lower speed than that in the ‘simple’ jet engine.
6. An alternative passage for the circulation of blood during a surgical operation (on the heart). Also attrib.
1957Times 1 Nov. 11/7 The circulating blood may have to be diverted and oxygenated through a by-pass circuit while the heart is opened, so that a defect within it may be rectified. 1961Lancet 22 July 182/2 The patient was on bypass for eighty-one minutes. Ibid., The first open repair on the heart, using a cardiopulmonary bypass, was carried out by Cooley et al. (1958).
Add:[6.] b. A permanent alternative pathway (usu. avoiding an obstruction or constriction) created surgically within the circulatory system (esp. in or near the heart or brain), alimentary canal, etc., incorporating a transplanted or synthetic vessel or chamber; also, an operation to create such an alternative route, or an artificial device incorporating one. Freq. attrib., esp. as bypass operation, bypass surgery.
1964H. Laufman in L. Davis Christopher's Textbk. Surg. xxix. 1275/2 The saphenous vein is used for by-passing, replacing or patching the femoral and popliteal arteries. When it is normal, its accessibility is a great advantage. However, it is not always available in sufficient length for by-pass surgery. 1970Sci. News Yearbk. 84 The DeBakey bypass, a spherical plastic chamber the size of an apple, skirts the heart's left ventricle, through which blood is normally pumped, and offers a parallel route. 1972P. F. Nora Operative Surg. xxxvii. 795 (caption) Bypass from subclavian to left carotid artery. 1984A. Smith Mind iv. xiv. 275 Neurosurgeons are now performing bypass operations to rearrange certain blood vessels over the brain. 1986Daily News (N.Y.) 23 May 65/3 A hospital spokeswoman said [he]..was awake and in stable condition after his bypass operation.
▪ II. by-pass, v.|ˈbaɪpɑːs, -æ-|
[f. prec.]
1. trans. To furnish with a by-pass.
1886Sci. Amer. Suppl. 4 Dec. 9099/3, I next by-passed the outlet valve with a one inch pipe. 1929Times 28 May 17/4 Schemes are on foot for by-passing both Leatherhead and Dorking.
b. To take an indirect route around, to avoid (a locality, military position, etc.).
1928Even. Standard 12 Mar. 6/2 King's Langley and Tring by passing Bushey and Watford. 1937Times 13 July 10/4 The scheme has been referred to as ‘the Selborne by-pass’, but it does not by-pass Selborne at all. 1942Hutchinson's Pict. Hist. War 10 June–1 Sept. 72/1 German armoured divisions which had by-passed our positions west of Mersa Matruh. 1959Listener 15 Jan. 115/2 We had to by-pass Tippaburra.
c. fig.
1941Spectator 10 Oct. 358/1 Congress is only one party in India, but by general consent it is the largest one, and it's no good trying to by-pass it. 1949Koestler Promise & Fulf. vii. 70 Conditioned during the course of a whole generation to bypass the law. 1959Listener 4 June 971/1 Whenever he was at odds with his Secretary of State he simply by-passed him.
2. To conduct (liquid, gas, etc.) by means of a by-pass.
1909in Cent. Dict. Suppl. 1922Encycl. Brit. XXX. 41/1 A valve for bypassing the whole or part of the exhaust gas directly into the atmosphere is provided to enable the output from the blower to be regulated. 1924Glasgow Herald 6 Nov. 9 A small portion of the gas..is by-passed to a boiler. |