| 释义 |
▪ I. quadrat|ˈkwɒdrət|
Also 8 quadrate.
[var. of quadrate n.1, in special senses.]
†1.
a. An instrument formerly used for measuring altitudes or distances, consisting of a square plate with two graduated sides, sights, etc. Obs.
a1400in Halliwell Rara Mathematica (1841) 65 When..þou wolde mesure þe heght..make a quadrat..þat es to sey a table even foure square of wode or brasse. 1617Minsheu Ductor, A Quadrat, or Geometricall instrument, whereby the distance and height of a place is knowne afarre off by looking thorow a certaine little hole therein,..dioptra.
b. Two graduated sides of a square, marked in the rectangular corner of a quadrant to facilitate its use. Obs.
a1400in Halliwell Rara Mathematica (1841) 59 Þe quadrat..whilk es descryvede..in þe quadrant has tuo sides. 1706Phillips (ed. Kersey), Quadrate and Line of Shadows (on a Quadrant) is a line of natural Tangents. 1727–41Chambers Cycl., Quadrat..called also geometrical square, and line of shadows, is an additional member on the face of the common Gunter's and Sutton's quadrants.
2. Printing. A small block of metal, lower than the face of the type, used by printers for spacing; abbrev. quad n.2
1683Moxon Mech. Exerc., Printing xxii. ⁋5 If his Title..make three or more Lines, he Indents the first with an m Quadrat. 1727–41Chambers Cycl. s.v., There are quadrats of divers sizes, as m quadrats, n quadrats, &c. which are respectively of the dimensions of such letters. 1824J. Johnson Typogr. II. iii. 65 An m-quadrat is the square of the letter to whatever fount it may belong; an n-quadrat is half that size. 1843Penny Cycl. XXV. 455/1 Larger quadrats, equal in body to two, three, or four m's.
attrib. and Comb.1683Moxon Mech. Exerc., Printing viii, Head sticks..are Quadrat high. 1894Amer. Dict. Printing s.v., To throw all the pi and broken letter..into the quadrat box.
3. Ecology. Each of a set of small measured plots of land, formerly usu. one metre squares, used in studying the local distribution of plants and animals. Also transf. (see quot. 1960).
1905F. E. Clements Res. Methods Ecol. iv. 161 Vegetation exhibits both development and structure, and is, in consequence, open to exact methods of inquiry. In the search for feasible methods, it was quickly seen that the quadrat, first used for determining the abundance of species, furnished the key to the problem. Ibid. 164 The unit size of quadrat is the meter, and when the term is used without qualification, it refers to the meter quadrat. 1922Ecology III. 158 He does not say whether the quadrats as counted were contiguous or scattered. 1939Clements & Shelford Bio-Ecol. v. 196 Cross checking rendered possible by his use of four methods, viz: trapping, censuses, hare transects, and quadrats of droppings. 1950Jrnl. Ecol. XXXVIII. 108 There has thus grown up in botanical ecology a study of the distribution of species in ‘quadrats’ or small samples of fixed area (usually 1 sq. m. or less) in which only the presence or absence of particular species is recorded and not its numbers. 1960New Phytologist LIX. 1 In the point quadrat method of vegetational analysis..thin needles are passed vertically through grassland..and the number of contacts between needles and foliage is recorded. 1974Nature 25 Oct. 713/2 It is difficult to estimate the number of snails in natural populations since they move around too slowly for ordinary capture-recapture methods, and their patchy distibution makes quadrat or transect counts unreliable.
▪ II. quadrat
obs. form of quadrate. |