| 释义 |
‖ torus|ˈtɔərəs|
Pl. tori |ˈtɔəraɪ|.
[L. torus a swelling, bulge, knot; muscle, brawn; bolster, cushion, couch, etc.: in Arch. a round moulding.]
1. Arch. A large convex moulding, of semicircular or similar section, used especially at the base of a column: resembling the astragal, but much larger.
1563Shute Archit. 11 The Torus, beneth shalbe y⊇ forth part greater then the Torus aboue. 1768Spence in Holdsworth Remarks Virgil 16 The plant which we see sometimes carved on the Torus of Pillars. 1854H. Miller Sch. & Schm. xiii. (1858) 271 Stairs of polished stone, ornamented in front and at the outer edge by the common fillet and torus. 1873Proc. Amer. Phil. Soc. XIII. 210 The tori were rudely cross-barred.
2. Bot. The swollen summit of the flower-stalk, which supports the floral organs: = receptacle 3 b, thalamus 2 a.
1829Loudon Encycl. Plants (1836) 537 Sisymbrium. Silique roundish, sessile upon the torus. 1880Gray Struct. Bot. vi. §1. 167 The Torus or Receptacle of the flower, also named Thalamus, is the axis which bears all the other parts.
3. a. Zool. A protuberant part or organ, as the ventral parapodia in some annelids. torus angularis, a single ossicle which articulates with a pair of interambulacral plates in some starfishes. b. Anat. ‘A smooth rounded ridge or elongated protuberance, as of a muscle; spec. the tuber cinereum of the brain’ (Syd. Soc. Lex.).
1877Huxley Anat. Inv. Anim. ix. 564 The free surface of the torus angularis lies in the walls of a sort of vestibule in front of the mouth.
4. Geom. Orig., a surface or solid generated by the revolution of a circle or other conic about any axis; e.g. a solid ring of circular or elliptic section. In mod. use, a surface or solid conceived of as generated by the circular motion of a circle about an axis outside itself but lying in its plane; also, any body topologically equivalent to this, having one hole in it but not necessarily circular in form or cross-section.
1870Cayley Math. Papers VII. 246 The ‘Conic Torus’, or surface generated by the rotation of a conic about a line whether not in or in the plane of the conic. 1871Ibid. VIII. 25 The general Torus, or surface generated by the rotation of a conic about a fixed axis anywise situate. 1958Times 25 Jan. 4/5 The Zeta apparatus is essentially a ring-shaped metal tube, or torus,..containing deuterium gas at low pressure. 1966E. H. Spanier Algebraic Topology 148 The surface with one handle is topologically the torus. 1976Offshore Platforms & Pipelining 49/1 The base structure consists of a torus through which the piles are placed. 1977Time 6 June 54/3 Tokamaks are toruses, or doughnut-shaped chambers, surrounded by huge electromagnets.
5. attrib. and Comb. (chiefly in sense 1).
1697Evelyn Archit. Misc. Writ. (1825) 378, I take a fillet to be more flat and torus-like. 1789Gentl. Mag. Dec. 1101/2 The torus cap that bears the plinth of the balustrade. 1842Gwilt Archit. §2129 The distinction between torus mouldings and beads in joinery is, that the outer edge of the former always terminates with a fillet, whether the torus be single or double. 1877Knight Dict. Mech., Torus Bead-plane, a certain form of plane for making the semicircular convex molding known as a torus.
Add:[2.] b. In some conifers and a few flowering plants: the thickened central part of a pit-membrane.
1887W. Hillhouse tr. Strasburger's Handbk. Pract. Bot. vi. 57 This delicate wall is the closing membrane. In the middle it is more strongly thickened, and forms the so-called torus. 1919F. O. Bower Bot. Living Plant xix. 306 The centre of the pit-membrane itself thickens, forming the ‘torus’, which serves mechanically to meet the risk of rupture following on any unequal pressure on the two sides. 1977K. Esau Anat. Seed Plants (ed. 2) viii. 108/1 No torus develops in the membrane of the half-bordered pit-pairs that occur in walls between conifer tracheids and parenchyma cells. |