| 释义 |
schliere|ˈʃlɪərə|
rare in sing. Also Schliere. Pl. -n, and erron. schliere, schlierin.
[Ger., f. regional schliere (fem.) striæ, streaks, corresp. to schlier (masc.) marl, f. early new HG. schlier (masc. and neut.), f. MHG. slier mud, related to MHG. slier, sliere ulcer, f. OHG. sclierrun (dat. pl.).]
1. a. Petrol. An irregular streak or mass in igneous rock differing transitionally from its surroundings in texture or composition, and usu. elongated by flow.
[1885A. Geikie Text-bk. Geol. (ed. 2) 94 Streaked, arranged in streaky inconsistent lines (Germ. Schlieren), either parallel or convergent, and often undulating.] 1888J. J. H. Teall Brit. Petrogr. ii. 40 The differential motion of the lava will tend to drag out any parts of exceptional composition into the form of streaks or elongated lenticles (schliere). 1898Jrnl. Geol. VI. 794 In the granites of Essex county are found in abundance streaks (Schlieren) and rounded rock masses of darker color and of finer grain than the surrounding rock. 1937Mem. Geol. Soc. Amer. No. 5. 25 Sheet-like bodies, in which certain minerals appear in abnormal proportions, are called flow layers, or schlieren. 1966McGraw-Hill Encycl. Sci. & Technol. VII. 15/2 Schlieren may represent early segregation drawn out by magma flow. Some may be xenoliths more or less digested and reworked by magma. Others may represent residual magmatic liquors of different composition injected into already crystallized portions. Schlieren formed in solid rocks are more properly metamorphic or metasomatic features.
b. A zone or stratum in a transparent medium whose density differs sufficiently from that of the surrounding medium for it to be detectable by refraction anomalies, usu. in consequence of pressure or temperature differences or composition inhomogeneities.
1895C. S. Palmer tr. Nernst's Theoret. Chem. i. v. 121 If one adds, by means of a capillary pipette, a drop of a strong solution of potassium ferro-cyanide to a moderately strong solution of copper sulphate, one can see with the naked eye that a schliere (i.e. thin layer) of concentrated solution of copper sulphate flows downwards. 1946F. Schneider Qualitative Organic Microanalysis ii. 22 The appearance of schlieren indicates the presence of impurities. 1949Proc. R. Soc. A. CXCVII. 485 However imperfect an electron lens may be from the point of view of theoretical optics, it can contain neither dust nor ‘schlieren’, as the electromagnetic field smoothes itself out automatically. 1965G. J. Williams Econ. Geol. N.Z. x. 149/1 The chromite occurs as..sporadic small narrow schlierin paralleling the enstatite crystal lamination... 1 to 3 mm schlierin in dunite show a local concentration of chromite. 1967Oceanogr. & Marine Biol. V. 107 These variations may appear as ‘Schlieren’, that is, as thin bands of water at the surface or at any depth.
2. attrib. uses of pl. schlieren, with reference to an experimental method for the observation and recording of schlieren in transparent media, in which the specimen is illuminated with a collimated beam of light, and the diffraction pattern resulting from localized refraction of light rays by the schlieren is photographed or displayed on a screen, as schlieren apparatus [ad. G. schlieren-apparat (A. Töpler Beobachtungen nach einer neuen optischen Methode (1864) 16)], schlieren illumination, schlieren method, schlieren photograph, schlieren photography, schlieren picture, schlieren system, schlieren technique.
1895C. S. Palmer tr. Nernst's Theoret. Chem. i. v. 121 Tammann observed the osmotic stream produced by the changes of concentration by means of a so-called schlieren apparatus. [Translator's note] This term, for which I find no concise English equivalent, is in common use in Germany to denote a delicate apparatus of Töpler used to detect small differences in the refractive power of the different layers (‘schlieren’) of heterogeneous media. 1933Jrnl. Scientific Instr. X. 381 (caption) General arrangement of ‘schlieren’ apparatus set up for photographic or screen observation. 1971Sci. Amer. May 118/1 In its simplest form the schlieren apparatus consists of a light source, two lenses, a pair of knife-edges and a sheet of photosensitive film.
1966D. G. Brandon Mod. Techniques Metallogr. 18 Some increase in sensitivity can be obtained if the stop is displaced from the image of the condenser aperture, so that the direct beam is merely reduced to the same intensity as the diffracted beam and not completely eliminated. This system is known as schlieren illumination and can be used to give accurate information on surface tilt.
[1899Phil. Mag. XLVIII. 218 (heading) Photography of sound⁓waves by the ‘Schlieren-Methode’.] 1933Jrnl. Scientific Instr. X. 378 The ‘Schlieren’ method is an old but little-known method of rendering visible either colourless fluids, which have a different refractive index from their surrounding medium, or variations of refractive index or thickness of transparent solids. 1940Nature 29 June 1021/1 The differentiation of the native proteins in the [egg] white was attempted on the basis of ionic mobilities by the method of Tiselius. The migration of the boundaries was followed optically by the ‘schlieren’ method using a sodium vapour lamp. 1962New Scientist 6 Dec. 576/1 The effects that make optical schlieren methods feasible become negligible in gases at very low pressures.
1953Proc. Inst. Mech. Engineers 1951–2: Automobile Div. 97/2 Observations by Miller of schilieren photographs taken during a very violent knocking combustion show a normal progression of the flame about three-quarters of the way across the combustion chamber. 1970New Scientist 18 June 581/1 Ultrasonic frequencies up to 40kHz radiated at the base of a roaring jet of burning gas have a marked effect on the flame, altering its appearance and cutting down the noise produced. This is clearly illustrated in the two sets of spark schlieren photographs of town gas diffusion flames... An acoustic frequency of 38kHz is responsible for the remarkable alteration seen in the schlieren pictures.
1931Trans. Inst. Mining Engin. LXXX. 18 Experiments carried out with Schlieren photography at Buxton are being supplemented at the U.S. Bureau of Mines Explosives Station at Pittsburgh. 1937Jrnl. R. Aeronaut. Soc. XLI. 621 By using ‘Schlieren’ photography the air flow, fuel injection and flame formation were recorded simultaneously. 1979Nature 29 Mar. 384/2 Drs Clark and B. J. Mullan used Schlieren photography to look at the air flow in and around cabinets running with and without an operator.
1957Liepmann & Roshko Elem. Gasdynamics vi. 161 Schlieren pictures are seldom used for a quantitative evaluation of density. They are, however, indispensable for obtaining qualitative understanding of flows. 1966McGraw-Hill Encycl. Sci. & Technol. XII. 68/1 Numerical values of density can be obtained only from schlieren pictures of airflow about two-dimensional models or about simple axisymmetric models. 1970Schlieren picture [see schlieren photograph above].
1949O. G. Sutton Science of Flight 203 Two other methods, the schlieren system and the interference method, are also in common use... The schlieren system uses either lenses alone or in combination with a concave mirror. 1956Nature 10 Mar. 485/1 A schlieren system has been combined with a rotating mirror camera so that the shock propagation can be recorded in the regions outside the arc as well as in the arc channel. 1966McGraw-Hill Encycl. Sci. & Technol. XII. 67/2 The schlieren system is used particularly in supersonic wind tunnels because it clearly shows the density gradients created by the shock and expansion waves of the airflow around the wind tunnel model.
1962New Scientist 6 Dec. 576/1 The Schlieren technique is an optical method of studying changes of density, and hence of refractive index, in transparent media.
Hence ˈschlieric a.
1921Geol. Mag. LVIII. 550 Mixed rocks, rocks which must be regarded as mixtures of carbonate magma of sövite type, and of the silicate rocks already enumerated are developed as schlieric intrusions, or as dykes cutting other members of the Fen group. |