| 释义 |
photo-|fəʊtəʊ|
before a vowel properly phot- (but often in full form photo- in Eng. compounds), repr. Gr. ϕωτο-, combining form of ϕῶς, ϕωτ- light.
1. Words in which photo- simply denotes ‘light’.
photoabˈsorbing ppl. a., that absorbs light; capable of absorbing a photon; photoabˈsorption, absorption of a photon; photoact |ˈfəʊtəʊækt| Biochem. = next; ˈphotoaction Biochem., a molecular event caused by light; photoˈactivate v. trans., to induce a change in or render active by means of light; hence photoˈactivated ppl. a.; ˌphotoactiˈvation, activation by means of light; photoˈactive a., capable of or involving a chemical or physical change in response to illumination; hence ˌphotoacˈtivity, the degree to which a substance or system is photoactive; photo-æsˈthetic a. [see æsthetic], perceptive of light; photoaˈffinity a. Biochem., applied to a technique of labelling large molecules (esp. proteins) at specific sites by means of molecules which initially form loose complexes at the active sites and are then photochemically converted in situ to reactive forms which immediately bond more permanently; so photoaffinity label n. and vb. trans.; photoˈallergy, an allergy brought about by light; hence photo-aˈllergic a.; ˌphotoassimiˈlation Biol., photo-synthetic assimilation; so photoaˈssimilate v. trans.; ˌphotoautoˈtrophic a. Bot. [after G. photoautotrophie n. (E. G. Pringsheim 1932, in Naturwiss. XX. 479/1)], autotrophic and obtaining energy from light; so photoˈautotroph, a photoautotrophic organism; photobacˈterium, a phosphorescent bacterium; photobiˈology, the study of the effects of light on living things; so ˌphotobioˈlogical a., photobiˈologist; photobiotic |-baɪˈɒtɪk| a. [see biotic], Bot., ‘living in the light; an epithet for certain vegetable cells’ (Syd. Soc. Lex.); photoˈbleaching, a loss of colour when illuminated; ˌphotoconˈversion Biochem., any reversible chemical change effected by light, esp. that of one form of phytochrome to the other; hence ˌphotoconˈvert v. trans., to change by photoconversion; ˌphotoconˈvertible a., capable of undergoing photoconversion; ˈphotocurrent, an electric current induced by illumination; ˈphotodamage, damage caused by (esp. ultraviolet) light; ˌphotodensiˈtometer, an instrument for measuring the density of a photographic negative or the opacity of a fluid; hence ˌphotodensiˈtometry; photoderˈmatic a. [Gr. δέρµα skin], having a skin sensitive to light; photodeˈstruction, destruction brought about by light; photodeˈtachment Physics, detachment of an electron from an atom caused by an incident photon; ˈphotodetector, a device that responds to incident light, esp. one whose operation depends on the electrical effect of individual photons; so ˌphotodeˈtection; ˌphotodisinteˈgration Nuclear Physics, the breaking up of a nucleus by the action of a gamma ray; ˈphotodrome [Gr. -δροµος -running, -runner, f. δρόµος running], an instrument for producing optical effects by flashes of light thrown upon revolving disks bearing figures or devices (Knight Dict. Mech. Supp. 1884); ˈphotoeffect Physics, a photoelectric effect, esp. the emission of an electron from an atom or of a nucleon from a nucleus by the action of a photon; photoeˈjection, ejection (of an electron from an atom) as a result of the absorption of a photon; ˌphotoelectroˈchemical a., of, pertaining to, or designating an electrochemical cell in which the electrode potential or the current flowing depends upon the degree of illumination of the cell; ˌphotoelectromagˈnetic a. Physics = photomagnetoelectric adj. below; ˈphotoenˌvironment, the environment formed by light; photoenzyme |ˈfəʊtəʊɛnzaɪm| Biol., an enzyme that catalyses a photochemical reaction; hence ˌphotoenzyˈmatic a., -enzyˈmatically adv.; photo-ˈepinasty Bot., ‘epinasty consequent upon exposure to bright light’ (Syd. Soc. Lex.); hence ˌphoto-epiˈnastic a., pertaining to or of the nature of photo-epinasty; ˌphoto-epiˈnastically adv.; ˌphoto-equiˈlibrium, state of equilibrium in regard to the vibrations of light; ˌphoto-exciˈtation Physics, excitation (sense 5) caused by light or by a photon; so ˌphotoexˈcited ppl. a.; ˈphotofabriˌcation, the manufacture of integrated circuits by photolithography; ˈphotofission Nuclear Physics, fission of an atomic nucleus caused by a gamma-ray photon; ˈphotoformer Electronics, an apparatus for generating a voltage corresponding to a given curve, incorporating a cathode-ray tube, a photo-electric cell, and an intervening opaque mask with an edge cut to the shape of the curve; ˌphotoheteroˈtrophic a. Bot. [after G. photoheterotrophie n. (E. G. Pringsheim 1932, in Naturwiss. XX. 479/1)], heterotrophic and obtaining energy from light; hence ˌphotoheteroˈtrophically adv.; also photoˈheterotroph, a photoheterotrophic organism; photo-ˈhyponasty Bot., ‘hyponasty consequent upon exposure to intense light following upon an arrest of growth’ (Syd. Soc. Lex.); hence ˌphoto-hypoˈnastic a., ˌphoto-hypoˈnastically adv.; ˌphotoinactiˈvation Biochem., destruction by light of the biological activity of an enzyme or other substance; photoˈlabile a., unstable in the presence of light; opp. photostable adj. below; hence photolaˈbility; photoˈlithotroph, a photolithotrophic organism; photoˈlithotrophy Bot. [Gr. λίθος stone + τροϕή nourishment], a form of nutrition in which energy is obtained photosynthetically from inorganic compounds; so ˌphotolithoˈtrophic a., characterized by photolithotrophy; ˌphotomagˈnetic a., (a) applied to certain rays of the spectrum having, or supposed to have, a magnetic influence; (b) = photomagnetoelectric; so photoˈmagnetism, photomagnetic property or character; that branch of physics which deals with the relations between light and magnetism; ˌphotomagˌnetoeˈlectric a. Physics, of, pertaining to, or designating an effect observed in some solids, whereby illumination of a solid subjected to a magnetic field parallel to its surface gives rise to a voltage at right angles to both the direction of the field and that of the illumination; ˈphotomask Electronics, in the manufacture of microcircuits, a photographic pattern through which a photoresist is irradiated with ultraviolet light in order to transfer the pattern on to it; photoˈmeson Nuclear Physics, a meson emitted from a nucleus as a result of the interaction of a gamma-ray photon with it; hence photoˈmesic a.; ˈphotomixer Physics, a device that acts as a mixer (mixer 2 c) for light waves; so ˈphotomixing vbl. n., the mixing of light waves in a heterodyne or homodyne process; photoˈneutral a., unaffected in some respect by light; photoˈneutron Nuclear Physics, a neutron released from a nucleus by the action of a gamma-ray photon; photoˈnuclear Nuclear Physics, of or pertaining to the interaction of a photon with an atomic nucleus; ˌphotoorˈganotroph, a photoorganotrophic organism; ˌphotoorgaˈnotrophy Bot. [Gr. τροϕή nourishment], a form of nutrition in which energy is obtained photosynthetically from organic compounds; so ˌphotoorganoˈtrophic a., characterized by photoorganotrophy; ˌphotoorganoˈtrophically adv.; phoˈtopathy [Gr. -πάθεια, πάθος suffering], the behaviour of an organism towards light, in moving towards or away from an illuminated region; hence photoˈpathic a.; photopeˈrimeter = perimeter 2; ˈphotophil (also -phile) a. [-phil], loving light, tending towards a lighted region; thriving best in abundant light; spec. [after G. photophil (E. Bünning 1944, in Flora CXXXVIII. 95)], applied to a phase of the circadian cycle of a plant or animal during which light tends to stimulate reproductive activity; photoˈphilic a. Biol. = next; phoˈtophilous a. Biol., light-loving; thriving best in abundant light; phoˈtophily, the state of being photophilous; photophob, -e a. [-phobe], having an aversion to light, given to retreating into the darkness; ˌphotophosphoˈrescent a., ‘becoming phosphorescent from the action of light’ (Syd. Soc. Lex.); photoˈphysical a., belonging to the physical effect of light (opp. to photochemical); so photoˈphysics n. pl. (const. as sing.); ˈphotopigment Biol., a pigment (e.g. in the eye) whose chemical state depends on its degree of illumination; ˈphotopile, an apparatus, resembling a thermopile, sensitive to light, as the sensitive selenium cells in the receiver of a photophone; ˌphotopolaˈrimeter, † (a) [ad. F. photopolarimètre (A. Cornu in Compt. Rend. Assoc. Française pour l'Avancement des Sci. 1882 253)], an apparatus for measuring the proportion of polarized light in a given beam (rare—0); (b) a telescopic apparatus for photographing distant objects (as planets) and measuring the polarization of light from them; hence ˌphotopolariˈmetric a., -polaˈrimetry; ˈphoto-potential, an electric potential generated by light; ˈphotoprocess, a (biological or chemical) process involving light; ˈphotoproduct, a product of the chemical action of light; ˈphotoproduction, production by light or by a single incident photon; so ˈphotoproduced ppl. a.; photoˈprotein Biol., any protein active in the emission of light by a living creature; photoˈproton Nuclear Physics, a proton released from a nucleus by the action of a gamma-ray photon; phoˈtopsia, ˈphotopsy [Gr. ὄψις vision], ‘a subjective sensation of light’ (Syd. Soc. Lex.); ˈphotoreaction, a photochemical reaction; photoreˈcovery Biol. = photoreactivation; photoˈregulate v. trans., to regulate (a biological process) by means of light; so photoˈregulated ppl. a.; ˌphotoreguˈlation, the act of photoregulating; photoˈregulator, a biological mechanism that regulates a process according to the duration, intensity, etc., of the light which it detects; ˈphotorepair Biol., repair of tissue brought about by the action of (visible or ultraviolet) light; so photoreˈpairable a.; ˌphotoreˈsistance Physics, (an) electrical resistance that is light-dependent; also, a photoresistor; ˌphotoreˈsistive a., exhibiting photoresistance; ˈphotoresistor, a resistor whose resistance varies according to its degree of illumination; ˈphotoresponse, a response to light; esp. a response of a plant mediated otherwise than through photosynthesis; so photoreˈsponsive a., -reˈsponsiveness; photoreˈversal, reversal of a (biological) process by the action of light; photoreˈversible a. Biol., capable of being reversed by the action of light; (of a substance) changing from one form into another and back again as the degree of illumination increases and decreases; hence ˌphotoreversiˈbility; photoˈsensor, a sensor that responds to light; photoˈsensory a. Biol., pertaining to or involving the perception of light; ˈphoto-shock Psychiatry [ad. F. photo-choc (Cossa & Gastaut 1949, in Ann. Médico-Psychologiques CVII. 187)], a flash or series of flashes of light given as part of shock therapy; photoˈstable a., stable in the presence of light; opp. photolabile adj. above; so photostaˈbility; photoˈstationary Chem., applied to a state of equilibrium in a photochemical reaction in which the rate of dissociation of the reactants equals their rate of recombination; ˌphotostimuˈlation, stimulation by means of light; so photoˈstimulate v. trans., photoˈstimulated ppl. a., -ˈstimulating vbl. n.; also photoˈstimulator, an apparatus used for photostimulation; ˌphotostimuˈlatory a., pertaining to or involving photostimulation; ˈphotosurface Electr., a surface which emits electrons when illuminated; ˌphototaˈchometer |-təˈkɒmɪtə(r)| [Gr. τάχος swiftness, ταχύς swift: see -meter], an apparatus for determining the velocity of light; so ˌphototachoˈmetric, -ical (also -tachy-) adjs., relating to the measurement of the velocity of light; ˌphototaˈchometry, the measurement of the velocity of light; ˈphototeˈlegraphy, ‘electric reproduction of pictures, writings, etc., at a distance; telephotography’ (Funk Stand. Dict.); in mod. use, a system of facsimile telegraphy in which variations of tone are adequately preserved; hence ˌphototeleˈgraphic a.; also photoˈtelegram, a telegram sent by phototelegraphy; photoˈtelegraph, an apparatus used for phototelegraphy; photoˈtelephone = photophone; ˌphototheraˈpeutic a. [see therapeutic], pertaining to ˌphototheraˈpeutics or photoˈtherapy, a system of treatment of certain skin diseases by exposure to particular light-rays, introduced by N. R. Finsen of Copenhagen; photoˈthermic a. [Gr. θέρµος heat], pertaining to the heating effect of light-rays; phototoˈxicity, the property of causing a harmful reaction to sunlight; so photoˈtoxic a.; ˌphototransforˈmation, a transformation (of a chemical compound) effected by light; photoˈtransient Chem., a short-lived molecular species produced by irradiation; ˈphototroph Bot., a phototrophic organism; ˈphototrophy Bot. [Gr. τροϕή nourishment], nutrition in which sunlight is utilized as a source of energy; so photoˈtrophic a., characterized by phototrophy; photoˈtrophically adv.; ˌphotovolˈtaic a., pertaining to, exhibiting, or utilizing the generation of an e.m.f. by light incident on an interface between certain pairs of substances; photovolˈtaics n. pl. (const. as sing.), the branch of science and technology concerned with photovoltaic effects and devices; hence photovolˈtaically adv.
1966Phillips & Williams Inorg. Chem. II. xx. 87 A biological system obtains energy from the oxidation of organic substrates or from the action of light on its *photo-absorbing pigments. 1977I. M. Campbell Energy & Atmosphere viii. 252 (heading) The generation of the photoabsorbing species and their relative significance.
1966Physical Rev. CXLIX. 55/1 (caption) Charge distribution of ions resulting from *photoabsorption primarily in the 3d shell of krypton. 1976Physics Bull. Dec. 544/2 The continuum states of two electron atoms and ions can be studied by electron scattering or by photoabsorption.
1971Nature 5 Feb. 372/1 The second possibility is that the mechanism of photosynthesis switches from a reaction involving two photosystems to a simpler form involving but one *photoact. 1971R. Gregory Biochem. of Photosynthesis ii. 36 Eight separate ‘photoacts’ are involved, so that we should expect 2500/8, say 300 chlorophyll molecules to be associated with each reaction centre.
1957Plant Physiol. XXXII. 397/2 Since the most probable photoreceptor is the oxidized form of the flavoprotein, the *photoactions are effective in its return to the reduced form. 1965Hendricks & Borthwick in T. W. Goodwin Chem. & Biochem. Plant Pigments xv. 409 Reversibility of light action..indicates that the photoactions are conversions of molecular configuration.
1926Ann. Rep. Progr. Chem. XXII. 340 In the case of chlorine,..W. Taylor draws the conclusion that only absorption within the continuous absorption band will *photoactivate the gas. 1959Mycologia LI. 87 Pigmentation was photo-activated. Light of wave lengths between 390 and 513 mµ stimulated the production of colour.
1926Ann. Rep. Progr. Chem. XXII. 360 In general, the ‘electron-loosening’ mechanism of Stark..describes the state of a *photo-activated molecule better than the other conceptions put forward by photochemists. 1954Jrnl. Res. Nat. Bureau of Standards (U.S.) LIII. 125 (heading) Catalytic photoactivated polymerization of tetrafluoroethylene.
1925Phil. Mag. XLIX. 1116 (heading) A note on the *photo-activation of chlorine. 1974Physiologia Plantarum XXXII. 228 (heading) Action spectrum for photoactivation of the water⁓splitting system in plastids of intermittently illuminated wheat leaves.
1908Physical Rev. XXVI. 541 A study of *photo-active effects produced by illuminating one electrode only, no external electromotive force being applied. 1951Sci. News XXII. 75 Perhaps indeed the carotenoids were the primaeval photoactive pigments which in the course of evolution of green plants and algae have been functionally although not physically replaced by..chlorophyll. 1975Nature 10 Apr. 507/2 The properties of an organic photovoltaic cell in which the photoactive material is microcrystalline chlorophyll-a.
1915Physical Rev. V. 45 This value of current was used in comparing the *photo-activity of solutions. 1970Biochim. & Biophys. Acta CCXXIII. 444 The photoactivity was measured by observation of the blue-shift.
1880Allman in Jrnl. Linn. Soc., Zool. XV. 137 Ascribing to the marginal bodies of the Hydroid Medusae a *photo-aesthetic function.
1970H. Kiefer et al. in Prov. Nat. Acad. Sci. LXVII. 1688 The method of affinity labeling is in widespread use for attachment of covalent labels at the active sites of protein molecules. The usual affinity-labeling reagent has the structure R—X, where R is the portion of the molecule that binds specifically and reversibly to the active site under study, and X is a chemically reactive group, such as diazonium or haloacyl... In *photo-affinity labeling, a reagent R—P is used, where P is a group that is ordinarily unreactive, but which can be converted by photolysis to an exceedingly reactive intermediate P*. Those molecules of R—P that are reversibly bound to the active sites react instantaneously upon conversion to R—P* before they can dissociate from the site. 1970Proc. Nat. Acad. Sci. LXVII. 1694 Binding sites of similar specificities in the same membrane preparation..may be photo-affinity labeled by the same reagents. 1976Nature 29 Apr. 802/1 Without irradiation the photoaffinity label reversibly inhibited the potassium conductance..whereas the sodium conductance was not affected. 1978Nature 12 Jan. 157/1 The modified pheromone is radioactively labelled, and since the carbene is generated photolytically, the process is called photoaffinity labelling.
1939Jrnl. Investigative Dermatol. II. 45 (heading) Mechanism of the *photoallergic reaction. 1968Hjorth & Fregert in A. J. Rook et al. Textbk. Dermatol. I. 300/1 Photo-allergic reactions can resemble sunburn. 1976Lancet 20 Nov. 1116/1 Chloroquine..is also used in..photoallergic reactions.
1939S. Epstein in Jrnl. Investigative Dermatol. II. 45 These experiments demonstrate a true allergic type of photosensitivity (*photoallergy). As far as I can see, this is the first report of this particular type of photosensitization and the first experimental proof of the allergic nature of this form of light sensitivity. 1976Arch. Dermatol. CXII. 1124/1 The diphenhydramine photoallergy was elicited by long-wave ultraviolet light.
1922Jrnl. Soc. Dyers & Colourists XXXVIII. 8/1 The green pigment chlorophyll has been shown by Willstätter to be an equilibrium mixture of chlorophyll A and chlorophyll B... This equilibrium is not appreciably altered when *photo-assimilation of CO2 is taking place. 1975Nature 9 Oct. 490/2 The ability of the cyanobacterium to *photoassimilate CO2 in reactions driven by photosystem I alone and using Na2S was demonstrated..; no photoassimilation was observed in the absence of sulphide or light.
1951J. W. Foster in Werkman & Wilson Bacterial Physiol. 363 *Photoautotrophs are those which utilize light. 1974Encycl. Brit. Macropædia X. 896/1 A green plant is a typical example of a photoautotroph.
1943Physiol. Rev. XXIII. 350 This..implies that the organism so operating must be capable of carrying out conversions of organic compounds. Theoretically it should even be able to grow heterotrophically on the proper organic substrates. Many of the *photo-autotrophic organisms have yielded to this treatment. 1975Nature 25 Dec. 715/1 Manganese is required for the photoautotrophic growth of O2-evolving organisms. 1977A. Hallam Planet Earth 189 This may bear some relation to the rapid evolution of photoautotrophic organisms such as blue-green algae.
1900Lancet 13 Oct. 1087/1 The peculiar greenish glow seen upon stale haddocks and other sea fishes is produced by this remarkable *photo⁓bacterium... By protracted exposure they [photobacteria] may be photographed by their own light.
1907Chem. Abstr. I. 190 (heading) The *photobiological sensitizers and their proteid compounds. 1976Sci. Amer. Feb. 119/1 The results of the experiment..also rule out for the wasp any model of a clock in which light induces, or starts, diapause or development by photobiological means other than mere entrainment.
1958Plant Physiol. XXXIII. 447/1 Robert Bruce Withrow died on April 8, 1958... With his passing this country lost one of its prominent *photobiologists. 1973Nature 6 July 37/1 Wald has therefore suggested that photobiologists should plot spectral functions on a frequency scale.
1935Science 31 May 526/2 The cure of rickets by ultra-violet light constitutes one of the most interesting chapters in *photo-biology. 1941H. F. Blum Photo-dynamic Action i. 3 Although..the phenomenon has been found to have a more limited significance in photobiology, the name photodynamic action has persisted. 1968New Scientist 5 Dec. 579/2 This Penguin survey is a valuable guide to the present knowledge and research work in photobiology.
1937Ann. Rep. Progr. Chem. XXXIII. 426 Considerations of the *photo⁓bleaching of fluorescent dyes in an oxygen-free atmosphere by the action of ferrous salts. 1974McGraw-Hill Yearbk. Sci. & Technol. 127/2 Light conversion in photo⁓active chlorophyll is accompanied by photobleaching and by the simultaneous appearance of a free or unpaired electron.
1952Jrnl. Chem. Soc. 4524 The *photoconversion of (I) and (III) into coloured forms does not occur with light of wave-lengths greater than about 540 mµ. 1964Photochem. & Photobiol. III. 521 The absorption spectra of the two forms of phytochrome show, in addition to the major absorption bands in the red and far-red regions, minor bands in the blue and near u.v. which are also effective in the photoconversions of phytochrome, PR {equil} PFR. 1971Nature 27 Aug. 602/1 The implication is that acetylcholine is involved in electrical changes in the plant which presumably follow the photoconversion of phytochrome.
1962Jrnl. Physical Chem. LXVI. 2476/1 Any X formed from B being immediately *photoconverted into A. 1970Nature 15 Aug. 666/1 The axis of orientation of the chromophores is parallel to the plasmalemma surface in the Pr form, but is changed to an orientation at 90° to the surface of the plasmalemma when photoconverted to Pfr.
1962Jrnl. Physical Chem. LXVI. 2469/2 Only this isomer is *photoconvertible into the spiropyran by visible light.
1913H. S. Allen Photo-Electricity x. 127 The proportionality factor between light absorption and *photocurrent is only independent of the angle of incidence ϕ for an electric vector..vibrating at right angles to the plane of incidence. 1913Physical Rev. I. 74 The photocurrent-potential curve was almost identical with that furnished by the mercury lamp. 1936Discovery May 151/2 This type of light-sensitive cell..requires no battery to obtain the photo-current. 1974Nature 26 Apr. 804/1 Light-induced release of protons might thus provide an alternative mechanism for generation of the photocurrents.
1973Nature 12 Jan. 133/1 This demonstrates the potential importance of the excited states of tryptophan as intermediates in lens *photodamage. 1977I. M. Campbell Energy & Atmosphere ix. 348 The link between DNA photodamage in living tissue cells and carcinogenesis by radiation is somewhat empirical.
1928Jrnl. Optical Soc. Amer. XVI. 222 A self-registering *photodensitometer has been described in which the direct-reading method and a thermocouple are employed. 1949Jrnl. Appl. Physics XX. 129/2 The specimen containing the diffused Na24 was placed directly on the emulsion for one-half hour... The plate was then developed and analyzed in a photo-densitometer. 1971Nature 19 Feb. 572/1 For most plant shoots, however, the change in methylene blue concentration is far too small to be accurately measured using standard photodensitometers. 1971Ibid. 16 July 185/1 The haloes were also evident in a photodensitomer profile across a cloud bank image, and extended 1 km from the cloud edge.
1965Biochemistry (Easton, Pa.) IV. 1653/2 Sometimes absorption optics are used on the ultracentrifuge, and in this event concentrations are measured by *photo⁓densitometry.
1889Nature 15 Aug. 384/2 Although these mollusks possess no eyes, they display extreme sensibility to light... It also appears that the *photodermatic (receptive) function is stimulated by luminous vibrations from without.
1964Jrnl. Cell Biol. XXII. 448/2 The most conspicuous structural change in the plastids during the 1 to 3 hours of *photodestruction of the pigments is the formation of stacked lamellar structures. 1977I. M. Campbell Energy & Atmosphere ix. 371 The minimum in the altitude concentration profile of nitric oxide with altitude near to 70 km is evidently a reflection more of the variation of production rate with altitude than of the variation of the photodestruction rate.
1943Phil. Trans. R. Soc. A. CCXXXIX. 278 (heading) *Photodetachment of electrons from normal O- ions. 1973Nature 26 Oct. 450/2 The profiles..confirmed the hypothesis that the daytime D region of the ionosphere below 80 km may be formed by photo-detachment of electrons.
1959Rev. Sci. Instruments XXX. 593/1 The application of the parametric amplifier principle to *photodetection. 1972S. S. Charschan Lasers in Industry ix. 523 In direct photodetection, all optical frequency and phase information is lost.
1947Proc. Nat. Electronics Conf. 1946 171 (heading) *Photodetectors for ultraviolet, visible and infrared radiation. 1959Proc. IRE XLVII. 1475/1 Until the early 1950's, the development of infrared photodetectors revolved principally around polycrystalline films of PbS, PbSe, or PbTe. 1967New Scientist 16 Nov. 416/1 The infrared radiation falls on the photodetector and produces visible radiation from the photoemitter. 1972S. S. Charschan Lasers in Industry ix. 529 Quantum or photo⁓detectors depend on the action of light quanta on a single electron rather than on the absorption and distribution of energy over an entire macroscopic body.
1935Proc. R. Soc. A. CLI. 481 The next point of interest is the probability of the ‘*photo’-disintegration. Ibid. 482 The effect of the γ-rays of radium in producing the photo-disintegration was also examined. 1942J. D. Stranathan ‘Particles’ of Mod. Physics xi. 444 Another illustration of photodisintegration is that of 4Be9. This reaction is 4Be9 + hv → 4Be8 + on1. 1968D. D. Clayton Princ. Stellar Evolution & Nucleosynthesis vii. 519 What happens then, as the temperature rises, may be described as a redistribution of loosely bound nucleons into more tightly bound states. We choose to call this process..photodisintegration rearrangement.
1903Encycl. Brit. XXXV. 729/4 (Index), *Photo-effect. 1913H. S. Allen Photo-Electricity i. 8 For substances which show only a ‘normal’ photo-effect the specific photo-electric activity increases continuously as the wave-length diminishes. 1938R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity (ed. 2) x. 123 These [γ-]rays are able to bring about nuclear photo-effects by the ejection of neutrons from the nuclei of various elements. 1960R. H. Bube Photoconductivity of Solids i. 2 Two new photoeffects were discovered in the early 1930s. In 1931, Dember..reported that a potential difference was developed in cuprous oxide in the direction of the light. 1974Encycl. Brit. Macropædia XV. 439/2 The photoeffect probability goes as approximately the fifth power of the atomic number of the absorbing material.
1966Physical Rev. CXLIX. 55/1 *Photoejection of a 3d electron. 1977I. M. Campbell Energy & Atmosphere i. 2 The photoejection of electrons from a metal surface irradiated with monochromatic..light.
1972Nature 7 July 37/2 If the energy of light is used effectively in an electrochemical system, it should be possible to decompose water with visible light. Here we describe a novel type of *photo-electrochemical cell which decomposes water in this way. 1976Ibid. 9 Sept. 100/1 Better and cheaper means of storing electricity..remain desirable, and hence the practical importance of photo⁓electrochemical decomposition of water into hydrogen and oxygen.
1953Proc. Physical Soc. B. LXVI. 743 If the slab [of germanium] is placed in a magnetic field perpendicular to the direction of illumination, a voltage is produced at right angles to both field and illumination (*photoelectromagnetic effect). 1965K. F. Hulme in C. A. Hogarth Materials used in Semiconductor Devices vi. 153 The theory and the constructional details and performance of a practical room-temperature photo⁓electromagnetic detector have been given. 1965M. Evenari in E. J. Bowen Recent Progress in Photobiol. v. 161 The ocean of light which constitutes the *photoenvironment. 1973Nature 6 July 37/1 The adrenal cortex, thyroid and pineal of birds are affected by the photoenvironment.
1962Jrnl. Gen. Physiol. XLV. 703 (heading) *Photoenzymatic repair of ultraviolet damage in DNA. 1975Nature 17 Apr. 627/1 If ultraviolet biological damage can be reversed by true photoenzymatic repair, then dimers have a major role in the production of that damage.
1966Adv. Radiation Biol. II. 23 A *photoenzymatically reversible competitive inhibition of transforming DNA repair in vitro.
1960*Photoenzyme [see photoreactivating ppl. a.]. 1966Adv. Radiation Biol. II. 19 This type of PR [sc. photoreactivation] does not result from the same type of photoenzyme.
1890Cent. Dict., *Photo-epinastic... *Photo-epinastically... *Photo⁓epinasty.
1924H. S. Taylor Treat. Physical Chem. II. xviii. 1239 With constant illumination, between reaction temperatures of 50 and 800° C., the *photo-equilibrium is the same, regardless of the gas temperature. This indicates that the temperature coefficient of the two photo-processes is the same. 1962Jrnl. Physical Chem. LXVI. 2472/2 In reversible photoisomerizations photoequilibrium is established when the rates of the two opposing photoreactions A {equil} B under the action of the particular photoactive light used, are equal. 1974Chem. Soc. Rev. III. 332 As the sensitizer energy is reduced the efficiency of sensitization of the cis-isomer falls below that of the trans. As a result there is a region where the trans-isomer is selectively excited and the proportion of cis-isomer at photoequilibrium is greater.
1918Physical Rev. XI. 485 Having followed the kathodo phosphorescence for 300 seconds by the usual well-known method of a single excitation and determined the form of the curve of decay, the relation of this curve to that obtained by *photoexcitation is of importance. 1946Nature 2 Nov. 603/2 In the large gap region it was necessary to increase the stress above that calculated, to provide the required photoexcitation. 1975McGraw-Hill Yearbk. Sci. & Technol. 357/1 In photoconductors the carriers can be generated internally by photoexcitation.
1954Ann. Rev. Plant Physiol. V. 277 In basic solvents like pyridine, *photoexcited chlorophyll can be reduced by ascorbate. 1970Physics Bull. Nov. 488/2 The migration of photoexcited electrons out of regions of high optical excitation to be entrapped in regions of low optical excitation.
1967Sci. Amer. Apr. 47 *Photofabrication starts with drawings and by chemistry and optics transforms them into the objects, usually with a linear reduction in scale. 1968Physics Bull. Dec. 423/1 The application of holography to..the photofabrication of microcircuits.
1939Physical Rev. LVI. 449/2 We can form an estimate of the cross section for *photo-fission by comparison with the yields of photoneutrons. 1974Encycl. Brit. Macropædia XIV. 299/2 More complicated [photonuclear] interactions involve either the emission of heavier particles.., many particles, or photofission.
1949Electronics Feb. 100/1 The *Photoformer, as it is called since it generates waveshapes through the use of a cathode-ray tube and phototube, is fed with a sawtooth voltage of the desired frequency. 1965Math. in Biol. & Med. (Med. Res. Council) i. 38 Figure 3 shows how an analogue computer is used to resolve such a curve into its components... A voltage generated from the curve by a photoformer is compared with the sum of exponentials generated in the computer.
1951J. W. Foster in Werkman & Wilson Bacterial Physiol. 364 The above two classes of autotrophs have their counterparts in the heterotrophic bacteria. Thus there are chemoheterotrophs and *photoheterotrophs... The latter are a specialized photosynthetic group which is capable of using for growth both radiant energy and preformed organic matter. 1963Studies on Microalgae & Photosynthetic Bacteria (Jap. Soc. Plant Physiologists) 465 Two characteristic facultative photoheterotrophs..have been examined for response to nitrate under various conditions of growth.
1945E. I. Rabinowitch Photosynthesis I. v. 106 The metabolism of the ‘*photoheterotrophic’ bacteria—that is, bacteria which require light for the assimilation of organic nutrients, seemed at first to be quite different from that of the ‘photautotrophic’ bacteria. 1975Nature 18 Dec. 631/1 Typical purple bacteria produce large quantities of molecular hydrogen during photoheterotrophic growth on organic acids.
1972Science 27 Oct. 404/3 Under anaerobic conditions in the light, cultures [of flexibacteria] grow *photoheterotrophically.
1938Recueil des Travaux bot. Né erlandais XXXV. 12 The decrease of the curvature with auxin-a by light must be ascribed to the *photo-inactivation of the auxin-a-lactone. 1973Biochemistry (Easton, Pa.) XII. 2540/2 Studies..on the photoinactivation of a purified bovine kidney mutarotase were undertaken.
1937Nature 25 Sept. 545/1 In the chicken retina, which contains principally cones, attempts to identify *photo-labile pigments heretofore have failed. 1975Ibid. 31 Jan. 316/2 Some photolabile metabolite accumulates until a threshold concentration is reached.
1961Webster, *Photolability. 1968Arch. Biochem. & Biophysics CXXIII. 109 (heading) Formation and photolability of a methyl cobalamin enzyme.
1958R. Y. Stanier et al. Gen. Microbiol. 669 The most familiar examples of the *photolithotrophs are the green plants, which use water as a hydrogen donor in photosynthesis. 1971J. S. Poindexter Microbiol. xxi. 473 Ectotrophic mycorrhizae are found in many forest trees... Generally, these trees are photolithotrophs as adults, and their seeds contain sufficient organic nutrients to provide the energy for germination and development of photosynthetic capacity. 1976Nature 18 Mar. 200/2 Photolithotrophs such as Thiorhodaceae or purple sulphur bacteria and Chlorobacteriaceae or green sulphur bacteria, learned, through photochemical promotion, to use inorganic reductants as electron donors.
1958R. Y. Stanier et al. Gen. Microbiol. xiv. 292 For the enrichment of chemolithotrophic and *photolithotrophic organisms, organic compounds must be omitted from the medium, and CO2 or bicarbonate must be used as the only source of carbon. 1972Goodwin & Mercer Introd. Plant Biochem. i. 3 The phototrophic bacteria are subdivided into photolithotrophic bacteria (e.g. green and purple sulphur bacteria) whose growth is dependent on exogenous inorganic hydrogen donors..and photo⁓organotrophic bacteria (e.g. purple, non-sulphur bacteria) whose growth is dependent on exogenous organic hydrogen donors. The biochemistry of photolithotrophic bacteria is related to that of green plants.
1947Cold Spring Harbor Symp. Quant. Biol. XI. 302 The following terminology is hereby proposed to characterize nutritional types [of microorganism]... A. Phototrophy. Energy chiefly provided by photochemical reaction. 1. *Photolithotrophy. Growth dependent on exogenous inorganic H-donors. 2. Photoorganotrophy. Growth dependent on exogenous organic H-donors. B. Chemotrophy. Energy provided entirely by dark chemical reaction. 1969F. E. Round Introd. Lower Plants i. 2 Photolithotrophy is the common photosynthesis of plants possessing chlorophyll a and using water as the hydrogen donor.
1858Mayne Expos. Lex. 948/2 *Photomagnetic. 1959R. A. Smith Semiconductors viii. 315 From equations (309) and (328) we may obtain an expression for the ratio of the photo-magnetic current per unit magnetic field to the photo-conductive current per unit electric field. 1975Physics Bull. Jan. 15/1 The materials in which such ‘photomagnetic’ phenomena have been observed so far are magnetic insulators or semiconductors.
1864Webster, *Photomagnetism, the relation of magnetism to light. Faraday.
1934Physik. Zeitschr. der Sowjetunion V. 597 (heading) On the explanation of the *photomagnetoelectric effect in semi-conductors. 1967R. H. Bube in Willardson & Beer Semiconductors & Semimetals III. xi. 473 The photomagnetoelectric (PME) effect provides a technique for the determination of minority-carrier lifetimes.
1965W. R. Runyan Silicon Semiconductor Technol. iv. 76 Silicon dioxide is very convenient to use as a mask since it can be easily delineated by standard *photomask techniques. 1977Sci. Amer. Sept. 114/3 Thus each photomask, typically a glass plate about five inches on a side, has a single pattern repeated many times over its surface.
1952R. E. Marshak Meson Physics iii. 104 The *photomesic production process probably leads, in the majority of cases, to excited states of the final nucleus having smaller spins than 4. 1974(title) Photomesic and photonuclear reactions and investigation methods with synchrotrons.
1950A. S. Bishop Photoproduction of Mesons from Hydrogen (Univ. of Calif. Radiation Lab., UCRL-874) 40 By definition, σ(Eph), the excitation function at 90° for *photo-meson production from protons, constitutes the probability that a photon of energy Eph, interacting with a proton, will produce a meson at 90° in the laboratory system. 1951Physical Rev. LXXXI. 189/1 The angular dependence of the nuclear cross section for photo-meson production..yields fairly direct information concerning the momentum distribution with[in] the nucleus. 1954Ibid. XCV. 592/2 (heading) Negative-to-positive ratio of photomesons from deuterium. 1955Ibid. XCIX. 1694/2 It is in the photoelectric mixing tube, or *photomixer,..that the beat frequency is generated. 1975Nature 13 Feb. 515/1 We have built a heterodyne spectrometer using..a HgCdTe photodiode as a photomixer.
1962Appl. Optics I. 51/1 This paper reports the observation of microwave signals produced by *photomixing of near-neighbour axial mode components in the output spectrum of a ruby optical maser. 1966M. Ross Laser Receivers iv. 125 Photomixing has been successfully achieved under laboratory conditions. However, no operational receiver incorporating photomixing has yet been announced.
1950Curtis & Clark Introd. Plant Physiol. xx. 630 Some plants are evidently highly indifferent to the photoperiod with respect to their flowering behavior and will flower over almost any photoperiod ranging from a 5-hr daily exposure to a 24-hr, or continuous, exposure. Some of the plants that fall into this indeterminate, or *photoneutral, group are buckwheat, sunflower, tomato, cotton, and dandelion. 1975Nature 25 Dec. 712/2 Natural populations of D. melanogaster and D. pseudoobscura are photoneutral in general, but respond rapidly to selection for positive or negative phototactic behaviour.
1935Proc. R. Soc. A. CLI. 488 The angular distribution of the *photo-neutrons from beryllium was investigated. 1975K. G. McNeill et al. in Jochim & Ziegler Interaction Stud. in Nuclei 451 Predictions have been made of the angular distributions of the photoprotons emitted from 40Ca and going to the ground state of 39K..and of the distribution of ground state photoneutrons.
1949Science 2 Dec. 579/1 There is an appreciable background of *photonuclear stars and proton tracks. 1959Deutsch & Kofoed-Hansen in E. Segrè Exper. Nucl. Physics III. x. ii. 305 Photonuclear reactions are sometimes used for the detection of high-energy gamma-rays and for the measurement of their energies. 1973Physics Bull. Nov. 694/3 The program will cover effective interactions in light nuclei, photonuclear reactions, neutron scattering below 15 MeV, [etc.].
1965A. H. Rose Chem. Microbiol. iii. 40 Thus we arrive at the following four nutritional categories of micro-organisms based on their energy-yielding metabolism: photolithotrophs, *photoorganotrophs, chemolithotrophs and chemoorganotrophs. 1976Nature 18 Mar. 200/2 Photo-organotrophs such as purple non-sulphur bacteria use as electron donors in the light, in anaerobic conditions, those organic electron donors which were used by fermenters in the dark.
1958R. Y. Stanier et al. Gen. Microbiol. xiv. 292 Since the *photoorganotrophic bacteria require various growth factors, a small amount of yeast extract is generally added to the enrichment medium. 1972Photoorganotrophic [see photolithotrophic adj. above].
1971J. S. Poindexter Microbiol. xiii. 154 The few types of algae that can grow *photoorganotrophically are aerobes.
1947*Photoorganotrophy [see photolithotrophy above].
1897C. B. Davenport Exper. Morphol. i. 185 A phototactic or *photopathic response has not hitherto been certainly observed in this group.
1897Ibid. 180 Control of the Direction of Locomotion by Light—Phototaxis and *Photopathy. [Note.] The second includes the wandering of organisms into a more or less intensely illuminated region.
1897C. B. Davenport Exper. Morphol. i. 181 According as the migration is towards or from the more intensely illuminated area, we can distinguish positive (+) and negative (-) photopathy; and correspondingly we.. speak of the organisms themselves as *photophil or photophob. In this nomenclature I follow Graber. Ibid. 194 Among Echinodermata, Asteracanthion rubens..appears to be photophil, and Asterina gibbosa..to be photophob. 1952Physiologia Plantarum V. 81 Bünning concluded that light is favourable to flowering during the ‘rising’ or photophile phase of the leaf movement, and inhibiting during the falling or scotophile phase. 1964E. Bünning Physiol. Clock xiv. 122 During the long dark period the plants endogenously reach a second ‘photophil’ state. 1965Plant Physiol. XL. 873/1 Light during the photophil phases may stimulate flowering to such an extent that..nearly every bud on the plant responds. 1975D. Vince-Prue Photoperiodism in Plants v. 170 He [sc. Bünning] proposed that photoperiodism involves a regular oscillation of phases or half-cycles with different sensitivity to light, and postulated that transfer to light sets in motion a photophile (or light-loving) phase, which is followed about twelve hours later by a skotophile (dark-loving) phase, also of twelve hours duration.
1900A. J. Ewart tr. Pfeffer's Physiol. Plants I. vii. 358 Even for light-loving (*photophilic) plants bright diffuse daylight seems as a general rule to be preferable to strong sunlight. 1967M. E. Hale Biol. Lichens v. 72 Photophilic algae as Pleurococcus, when lichenized would be inhibited by reduced light.
1905I. B. Balfour tr. C. E. von Goebel's Organogr. Plants II. 463 They [sc. geophilous shoots]..are united by many intermediate stages with ‘*photophilous’ shoots. 1967M. E. Hale Biol. Lichens vii. 87 The photophilous (light-loving) characteristics of most lichens.
1934Webster, *Photophily. 1960Cold Spring Harbor Symp. Quantitative Biol. XXV. 241/1 The phase of strongest responsiveness to temperature in both types coincides with maximum responsiveness to light..: with maximum photophily in long-day plants and maximum scotophily in short-day plants. 1974Biol. Abstr. LVII. 762/1 An ecological scale of photophily was developed.
1897*Photophob [see photophil adj. above.].
1888Meldola Chem. Photogr. i. (1889) 8 *Photo-physical changes requiring more or less time for their completion. 1889Athenæum 26 Oct. 562/3 The author discriminates between photo-physical changes, that is, those in which the chemical composition of the substance exposed to light is in no way altered, and photo-chemical changes. 1914S. E. Sheppard Photo-Chem. p. vii, There exists..some difference of opinion as to the desirability of incorporating a discussion of photo-physical and radiation phenomena and laws in a work on photo-chemistry. 1971Physics Bull. Sept. 546/1 (Advt.), A comprehensive treatment is given of the interactions of low energy electrons with atoms and molecules, and photophysical processes. 1976Nature 15 Apr. 654/2 Two chapters deal with photophysical processes: the first is a brief survey of the electronic spectroscopy of complexes.
1961M. Calvin in McElroy & Glass Symposium on Light & Life 317 A discussion of some of the photochemistry and *photophysics of porphyrins. 1970J. B. Birks Photophysics of Aromatic Molecules p. vii, There are six related subjects concerned with the interaction of radiation with molecular systems: photophysics, photochemistry and photobiology, which deal with optical non-ionizing radiation; and radiation physics, radiation chemistry and radiation biology, which deal with ionizing radiation. Photophysics is the keystone of the structure, since it is an integral constituent of each of the other five subjects.
1937Nature 25 Sept. 545/2 The familiar Purkinje effect, for which clearly the extracted *photo-pigments form an adequate chemical basis. 1964S. Duke-Elder Parsons' Dis. Eye (ed. 14) xxiv. 364 It [sc. colour blindness] is an inherited condition,..and is probably due to the absence of one of the two photopigments normally found in the foveal cones. 1970Hand & Davenport in P. Halldal Photobiol. of Microorganisms ix. 278 The photopigment responsible for photoaxis and photokinesis is probably flavin.
1884C. G. W. Lock Workshop Receipts Ser. iii. 180/1 The resistance of the whole *photopile is reduced to a minimum. 1884Knight Dict. Mech. Supp. 675 (title of Fig. 1908) Bell's Photo⁓pile of Receiver.
1971Time 15 Mar. 46 Light measurements by Pioneer's imaging *photo-polarimeter will enable computers on earth to construct about ten pictures of the planet [sc. Jupiter] that will show features as small as 250 miles across. 1972Daily Colonist (Victoria, B.C.) 25 Feb. 5/2 In the last 20 hours before closest approach, the spacecraft's imaging photopolarimeter will take 100 pictures of the planet. 1974Nature 6 Sept. 18/1 The imaging photopolarimeter of Gehrels et al. contained a 2·5 cm telescope which made maps of Jupiter.
1971Icarus XV. 454 (heading) *Photopolarimetric observations of the minor planet Flora.
1974Sci. Amer. Feb. 43/1 More detailed knowledge of the planet's atmosphere awaits analysis of *photopolarimetry measurements.
1914Physical Rev. IV. 229 The results as a whole confirm the point of view adopted by Richardson and Compton in regard to the relation between *photo- and contact potentials. 1924Jrnl. Physical Chem. XXVIII. 333 Becquerel was the first to observe that the photo-potential of the silver iodide electrode: electrolyte cell was not always positive. 1976Nature 9 Sept. 99/2 If we want to use a semiconductor with an optical bandgap, so as to give optimal utilisation of solar radiation.., the maximum photopotential attainable will be ∼0·4 eV.
1924*Photoprocess [see photo-equilibrium above]. 1926Trans. Faraday Soc. XXI. 560 Weigert sees in the photosensitisation of ozone decomposition by chlorine, the simplest possible photoprocess. 1959W. H. Klein in R. B. Withrow Photoperiodism iii. 207 (heading) Interaction of growth factors with photoprocess in seedling growth. 1974Photochem. & Photobiol. XIX. 441/2 The versatility of flavins as photosensitizers in numerous photoprocesses.
1953Physical Rev. XCI. 480/2 The cross section obtained in this way is modified principally by the presence of terms describing the multiple scattering of the *photo produced mesons. 1973Physics Bull. July 431/1 Modulation excitation (me) spectrophotometry is a technique to measure the absorption spectra of short lived photoproduced transients, such as excited states of molecules.
1926E. Mayer Clin. Applic. Sunlight iii. 30 This action of small doses of radiant energy may be due to toxic ‘*photo-product’. 1941Brit. Jrnl. Psychol. XXXII. 79 The rate of dark adaptation is supposed..to be determined by the concentration of photoproduct present at each moment. 1977Nature 17 Feb. 660/2 Comparison of spectra taken before and after prolonged irradiation..showed no change in the relative position or intensity of the shoulder, eliminating a permanent photoproduct generated by the high intensity pulse as the species responsible for the shoulder.
1950Federation Proc. IX. 544/1 (caption) *Photoproduction of H2 from succinate by Rhodopseudomonas gelatinosa. 1950A. S. Bishop Photoproduction of Mesons from Hydrogen (Univ. of Calif. Radiation Lab., UCRL-874) 5 From the measured energy distribution of the mesons at 90°..it is possible to determine the excitation function for photoproduction of mesons at 90°. 1961Nature 13 May 602/1 Photoproduction of hydrogen gas by photosynthetic cells was first observed..in the green alga Scenedesmus. 1974Frauenfelder & Henley Subatomic Physics xii. 326 (caption) Total cross sections for the photoproduction of neutral and charged pions from hydrogen, as a function of the incident photon energy.
1966Shimomura & Johnson in Johnson & Haneda Bioluminescence in Progress 495 Solutions of the protein, for which the general term ‘*photoprotein’ is suggested, show a fluorescence maximum at 458 mµ when excited at 350 mµ. Ibid. 497 As a convenient, general designation of the active component in the hydromedusan and Chaetopterus type of system, to which the terms ‘luciferin’ and ‘luciferase’ do not apply in their usual meaning, we propose the term ‘photoprotein’. 1975Nature 17 July 236/2 The photoprotein aequorin (molecular weight about 30,000) isolated from the bioluminescent jellyfish Aequorea aequorea emits blue light.
1935Chadwick & Goldhaber in Proc. R. Soc. A. CLI. 480 The experimental arrangement for the detection of the protons released from deuterium, which we may for convenience call ‘*photo’-protons, was as follows. Ibid., An estimate of the energy of the photoprotons can be deduced from the measurement of the size of the oscillograph kicks. 1975Photoproton [see photoneutron above].
1844Dunglison Med. Lex., *Photopsia. 1858Mayne Expos. Lex. 649/1 Photopsy. 1889Lancet 28 Dec. 1331/1 In the optic nerve these conditions cause photopsia or flashes of light, flames, sparks, and stars.
1909Jrnl. Chem. Soc. XCV. 442 That most remarkable *photo-reaction which Marckwald..has named phototropy. 1925H. S. Allen Photo-Electricity (ed. 2) xiv. 235 Perrin has developed..the view that ‘ordinary’ chemical reactions may be regarded as due to radiation, i.e. they are photo-reactions. 1975D. Vince-Prue Photoperiodism in Plants iv. 146 The photoreactions which control the induction of flowering in LDP [sc. long-day plants] and SDP [sc. short-day plants] are remarkably similar.
1950Proc. Nat. Acad. Sci. XXXVI. 626 The *photorecovery after ultra-violet radiation, manifested by the Arbacia egg, seems in all ways parallel to the ‘photoreactivation’ in fungi and bacteria. 1974Encycl. Brit. Macropædia XV. 390/1 It is probable that photorecovery mechanisms are continually operative in some plants exposed to direct action of sunlight.
1969Proc. Nat. Acad. Sci. LXIV. 1103 The enzymic activity of acetylcholinesterase can be *photoregulated through the mediation of photochromic inhibitors of the enzyme.
1957Bot. Gaz. CXVIII. 207/2 Flowering, seed germination, and certain other *photoregulated phenomena. 1970Proc. Nat. Acad. Sci. LXVI. 853 A systematic study of the interaction of naturally occurring carotenoids with various enzyme systems might provide information useful for an understanding of photoregulated processes found in nature.
1968Science 27 Dec. 1487 (heading) *Photoregulation of an enzymic process by means of a light-sensitive ligand. 1970Proc. Nat. Acad. Sci. LXVI. 850 A possible role in photoregulation is suggested for naturally occurring carotenoids.
1959R. J. Downs in R. B. Withrow Photoperiodism ii. 129 The woody plant thus appears to be running two different systems with the same *photoregulator. 1970Nature 22 Aug. 778/1 Bieth et al. conjecture that carotenoids of animals and plants..might function as photoregulators, controlling diurnal and seasonal changes in metabolic levels.
1967Mutation Res. IV. 22 The impossibility of attaining complete *photorepair of lethal and mutagenic damage raises the important question of whether there is a qualitative difference between damage which is photoreactivable and damage which is not. 1978Nature 31 Aug. 891/1 Forward mutations at a variety of loci in rad 1–1 yeast are also subject to photorepair.
1966Adv. Radiation Biol. II. 49 The number of *photorepairable lethal lesions in..DNA. 1978Nature 31 Aug. 890/2 As many as 80% of the extra lys+ revertants are photorepairable and therefore dimer-associated in origin.
1925Astrophysical Jrnl. LXII. 317 (heading) Apparent *photoresistance effects. 1957Chem. Abstr. LI. 7134 At low levels of ionizing radiation CdS photoresistances exhibited considerable inertness. 1970New Scientist 14 May 335/1 The rate at which the charge of any photo-element leaks away between sweeps depends upon the value of the photo-resistance. 1978Nature 23 Mar. 315/1 The light rays impinged on the photoresistances L1 and L2, which formed a bridge circuit with the variable resistances R1 and R2.
1933Jrnl. Inst. Electr. Engin. LXXIII. 437/1 The first step towards the conversion of the picture into electrical energy was taken by May in 1873, with his discovery of the *photo-resistive property of selenium. 1973Sci. Amer. Jan. 116/3 Selenium and cadmium photocells are more sensitive, but they are of the photoresistive type and require an external source of power.
1959Chem. Abstr. LIII. 13793 (heading) Germanium *photoresistors. 1965Lindmayer & Wrigley Fund. Semiconductor Devices x. 384 Photoresistors made from nearly intrinsic polycrystalline thin films are very sensitive detectors for the average intensity of a wide source spectrum. 1969New Scientist 18 Sept. 568/3 Shamer and Fox observed no fringe shift using..sensitive photoresisters to detect the fringe positions. 1977J. Hedgecoe Photographer's Handbk. 21 (in figure) Cds photo-resistor cell.
1950Ann. Rev. Plant Physiol. I. 43 The *photoresponses of plants at different ages or stages of development may be opposite. 1955Hendricks & Borthwick in Proc. 1st Internat. Photobiol. Congr. i. 23 Photoresponses controlling etiolation of plants and germination of seeds are also examples [of photoperiodism]. 1971Jrnl. Appl. Physics XLII. 568/2 Additional silver increases the photoresponse. 1976Nature 19 Aug. 680/2 For photoresponse spectra, electrodes were illuminated by 400-Hz chopped, monochromatic radiation.
1955Hendricks & Borthwick in Proc. 1st Internat. Photobiol. Congr. i. 31 Flowering in *photo-responsive plants can be controlled through a single leaf in the presence of other leaves. 1974Nature 26 Apr. 800/2 If the cells of D. discoideum are broken gently in a Dounce homogenizer, the photoresponsive pigment sediments with the mitochondrial fraction collected by differential centrifugation between 6,000 and 10,000 g.
1972Science 27 Oct. 421/2 Severance of the optic nerve in immature male ducks decreased the *photoresponsiveness to one-fifth of the normal.
1954Bot. Gaz. CXV. 216/2 (heading) *Photoreversal of promotion and inhibition of germination of Grand Rapids lettuce seed at 20°C. after irradiation at 26° and 6°–8°. 1966Adv. Radiation Biol. II. 20 The direct nonenzymatic photoreversal of UV damage to DNA.
1954Hendricks & Borthwick in D. Rudnick Aspects of Synthesis & Order in Growth vii. 159 Some further details about the several *photoreversibilities. 1955Plant Physiol. XXX. 468 (heading) Photoreversibility of leaf and hypocotyl elongation of dark grown red kidney bean seedlings. 1975D. Vince-Prue Photoperiodism in Plants iv. 108 Extracts of leaves of several species have been found to show photoreversibility.
1954Hendricks & Borthwick in D. Rudnick Aspects of Synthesis & Order in Growth vii. 154 The cuticle coloration response..is *photoreversible. 1966Adv. Radiation Biol. II. 21 The photoreversible effects of UV on cytoplasmic entities of cells..formerly suggested RNA damages. 1972W. Shropshire in Mitrakos & Shropshire Phytochrome p. v, Phytochrome is a photoreversible pigment which can exist in two principal forms.
1962Instrument Pract. XVI. 1519/2 (heading) Subminiature *photosensors. 1964New Scientist 4 June 594/2 The photo-sensor is simply a detector which changes light into an electrical signal... Several types exist, such as photo-emissive cells, photo-conductors, photo-voltaic cells, and photo-transistors. 1975Physics Bull. Feb. 82/3 The solid state cameras..replace the bulky Vidicon tube normally used by an array of 104 photosensors, which have a broad spectral response.
1919Jrnl. Gen. Physiol. I. 556 The *photosensory responses of an animal like Mya. 1972Internat. Jrnl. Neurosci. III. 145 (heading) Photosensory cell of the flatworm ocellus.
1953Amer. Jrnl. Psychiatry CIX. 744/1 Although the method for producing convulsions (*photoshock) presented here may be considered similar to that of Metrazol shock, it is our impression that this modified procedure has several possible advantages. 1955Sci. News Let. 21 May 325/1 Instead of electric current, a flashing light is used for ‘photo-shock’ treatment.
1936Jrnl. Gen. Physiol. XX. 52 The ammoniacal retina bleaches more slowly than the neutral tissue. This difference cannot be ascribed to induced *photostability in the visual purple itself. 1965J. B. Thomas Primary Photoprocesses in Biol. iv. 85 The acid-resistance as well as the photostability of suspensions of such native chlorophyll are much higher than those of dissolved chlorophyll. 1977Protecting World's Crops (Shell Internat. Petroleum Co.) 2 Recently, however, compounds have been synthesized which combine with photostability remarkable activity against insects.
1921Jrnl. Gen. Physiol. III. 380 The filters are quite *photostable. But in order to avoid any possible bleaching effect, a shutter is placed between the light source and the filter. 1973Photostable [see photocatalysed ppl. adj. s.v. photocatalyse v.].
1924Trans. Faraday Soc. XX. 112 The decomposition of sulphur dioxide gas under the action of light radiated from a uviol mercury lamp has been investigated, and the resulting *photostationary state, characteristic of a given set of conditions, determined, using a number of different light filters. 1972W. Haupt in Mitrakos & Shropshire Phytochrome xxi. 561 Whenever a randomly distributed population of phytochrome molecules is irradiated, light is absorbed by Pr and Pfr to different extents... This difference leads to a photostationary state of Pfr/P which depends only on the wavelength and which can therefore be predicted precisely.
1956Nature 21 Jan. 143/1 Attempts to *photostimulate tropical birds have been rare, and the results confusing. 1971New Scientist 29 July 255/1 Since it seems that the timing of a light stimulus rather than its duration might be important it is conceivable that a bird could be photostimulated with even very small daily doses of light that would normally be non-stimulatory.
1959D. S. Farner in R. B. Withrow Photoperiodism x. 729 In domestic ducks..both ocular and encephalic receptors are involved in *photostimulated testicular development. 1970Proc. Nat. Acad. Sci. LXVI. 850 (caption) Photostimulated cis-trans isomerism.
1967Ibid. LVIII. 2129 The initial *photostimulating step..is postulated as being followed at some stage by release of a ‘hormone’, the hypothetical ‘florigen’.
1937Jrnl. Exper. Biol. XIV. 86 Many shallow-water teleosts,..when blinded, show a pigmentary response to *photostimulation. 1955Sci. News Let. 21 May 325/1 The flashing light shock is given after patients have had injected into their veins the drug, Azozol... Results were compared with..another group given less intensive ‘photostimulation’, in which smaller quantities of the drug were used and the light flashes were interrupted oftener. 1959D. S. Farner in R. B. Withrow Photoperiodism x. 724 These investigations suggest that photostimulation of gonadal development does not involve entirely the same receptors as are involved in vision. 1967Psychol. Abstr. XLI. 1499/1 The role of intermediary structures of the brain in the formation of certain functional relationships in the human CNS was studied, employing single, rhythmic, and interrupted photostimulation in Ss with lesions of the diencephalic region and brain stem. 1971Nature 18 June 465/1 The lamp of the *photo-stimulator was above and behind an animal's head at 110 cm from the centre of the hemisphere. 1976Ibid. 3 June 423/2 *Photostimulatory cues..influence the hypothalamic input to the pars intermedia.
1939Jrnl. Inst. Electr. Engin. LXXXV. 472/2 The optical picture to be transmitted is focused on a continuous transparent *photo-surface. 1952Electronic Engin. XXIV. 302/1 The spectral response curves of these photosurfaces are compared. 1970Proc. IEEE LVIII. 1794/1 The AgOCs photocathode, the only photosurface to give appreciable response beyond 1 micron until recently.
1886Athenæum 3 July 21/1 An account of Prof. Newcomb's determination..of the velocity of light. The apparatus employed, to which the name of ‘*phototachometer’ was given.
1882Harkness in Nature 30 Nov. 117/2 The solar parallax..cannot be regarded as exactly known until the results obtained from trigonometrical,..and *phototachymetrical methods are in perfect harmony.
1929Telegraph & Telephone Jrnl. XVI. 3/2 *Photo-telegrams will have to be charged by space measurement instead of the number of words. 1948Post Office Guide 283 A reply voucher issued with a phototelegram may be used to prepay an ordinary telegram. 1968Guardian 10 Apr. 8/3 To quote the bleak prose of Her Majesty's Post Office, ‘Telex—no service. Phototelegrams—no service. Telephone—no service.’
1909Electrical Mag. XII. 249/1 (heading) The Sémat *phototelegraph. 1949Post Office Electr. Engineers' Jrnl. XLI. 189 (heading) The Post Office phototelegraph service to Europe. 1959J. W. Freebody Telegr. xiii. 538/2 (heading) The Muirhead-Jarvis photo-telegraph equipment.
1909Electrical Mag. XI. 57/1 New York, Chicago, and other cities are now about to commence *photo-telegraphic trials. 1940Wireless World Sept. 398/3 The clarity of reception, at a distance of 12,000 miles, of photographs transmitted from the West Base of the U.S. Navy Antarctic Expedition, is attributed to the use of a recently developed phototelegraphic technique to counteract selective fading of the carrier frequency.
1886W. Gemmill Brit. Pat. 4841 6 It will be seen that the system of *photo-telegraphy opens up an entirely new field in telegraphy, namely the actual reproduction of photographs through the medium of electrically conducting wires. 1930Post Office Electr. Engineers' Jrnl. XXIII. 1/2 British newspapers using photo-telegraphy transmit to and from London and their provincial offices using ‘Four-Wire’ telephone circuits. 1976R. N. Renton Telegr. iv. 60/1 Telephone circuits are used as the ‘bearer’ circuits for multiplex telegraph systems and for phototelegraphy.
1904Daily Chron. 26 Sept. 5/5 Further experiments in *phototherapeutics dealt with the bactericidal effects of concentrated violet rays in cases of lupus.
1899Allbutt's Syst. Med. VIII. 796 The latest addition to our practical resources is the ‘*photo⁓therapy’ of Finsen of Copenhagen. 1903Westm. Gaz. 24 June 9/1 The new cure of lupus by phototherapy has been most successful.
1891Anthony's Photogr. Bull. IV. 359 The *photothermic energy in the luminous spectrum.
1942S. Epstein in Jrnl. Investigative Dermatol. V. 290, I propose the term ‘*phototoxicity’ for the primary, non-allergic photosensitivity, and ‘*phototoxic reaction’ for the effect produced by this mechanism... Phototoxic reactions apply indiscriminately to all individuals. 1974M. C. Gerald Pharmacol. xxvii. 471 Demeclocycline has been shown to cause phototoxicity in some patients, where severe burns develop when susceptible patients are exposed to sunlight. 1976Arch. Dermatol. CXII. 327/1 The duration of methoxsalen's phototoxic potentiality, after its application to skin, varied in direct proportion to chemical concentration.
1962Jrnl. Physical Chem. LXVI. 2470 The results indicate the occurrence of consecutive and concurrent *phototransformations and thermal interconversions between stereoisomers of the colored modification. 1975D. Vince-Prue Photoperiodism in Plants vi. 215 The general conclusion..is that the phototransformation of phytochrome may very rapidly lead to an alteration of membrane properties.
1973Physics Bull. July 431/1 It is obvious that for light induced species with large lifetimes, a simple dc method would suffice to measure their absorption. However, with the short lifetimes associated with excited states, the changes occurring in dc current by the absorption of the *phototransient will be much smaller than the noise. 1975Nature 25 Dec. 767/2 Evidence was obtained that this phenomenon is a consequence of an overlap from a shorter lived phototransient (maximum about 530 nm) which is the precursor of the 410-nm species.
1941R. P. Hall in Calkins & Summers Protozoa in Biol. Res. ix. 477 Some [chlorophyll-bearing protozoa] appear to be obligate *phototrophs. 1965A. H. Rose Chem. Microbiol. iii. 39 Only a minority of micro-organisms including algae and photosynthetic bacteria and protozoa are able to utilize directly the energy of solar radiation. These organisms are described as phototrophs to distinguish them from chemotrophs. 1975Nature 7 Aug. 463/2 This versatility would give it a clear advantage over other blue-green algae (mostly obligate phototrophs) as well as over bacteria.
1939H. W. Harvey in P. D. Trask Recent Marine Sediments ii. 145 Although plants are occasionally found down to considerable depths, they can only grow and increase down to a depth to which sufficient light penetrates. In clear blue-green water of temperate regions this *phototrophic zone may extend down to 30 or 50 meters in summer time. 1965Pelczar & Reid Microbiol. (ed. 2) vi. 496/2 Phototrophic organisms are regarded as the most important plankton organisms since they are the primary producers of organic matter via photosynthesis. 1972Phototrophic [see photolithotropic adj. above]. 1973Biochim. & Biophys. Acta CCCXXX. 80 (heading) Membrane differentiation in *phototrophically growing Rhodospirillum rubrum during transition from low to high light intensity.
1947*phototrophy [see photolithotrophy above]. 1959Lamanna & Mallette Basic Bacteriol. (ed. 2) xi. 467 (heading) Phototrophy.
1923Jrnl. Physical Chem. XXVII. 601 The terms ‘Becquerel effect’ and ‘*photo-voltaic effect’ have been used to distinguish between the light-sensitive systems of the electrode-electrolyte type and the well known ‘Hallwachs effect’ or ‘photo-electric effect’. Cells having one or more light-sensitive electrodes of the former type are able to convert radiant energy into electrical energy and have been called ‘photo-voltaic cells’. 1943D. H. Jacobs Fund. Optical Engin. xxiii. 377 Some problems in instrument design call for vacuum or gas-filled photoemissive cells, and some call for photovoltaic cells. 1953Amos & Birkinshaw Television Engin. I. iii. 41 An electrode may, however, be sensitive to light in other ways; for example, it may be photo-voltaic, i.e., develop e.m.f.s when illuminated. 1957Proc. Inst. Electr. Engin. CIV. B. 467/1 In 1839 Becquerel had found that, when light fell on two metal electrodes immersed in an electrolyte, a potential difference was established between them; this is now known as the photo-voltaic effect. 1964Oceanogr. & Marine Biol. II. 359 Clark (1933) demonstrated the correlation between diurnal migration of plankton and changes in submarine irradiation by means of a photo-voltaic cell. 1977Undercurrents June–July 8/2 A comparison of fast breeder reactor technology with photo-voltaic (solar cell) technology neatly illustrates the two poles of opinion. 1978Solar Energy (Shell Internat. Petroleum Co.) 5 A second way of using sunlight is *photovoltaically—the direct conversion of sunlight into electricity.
1973Physics Bull. Jan. 53/3 Papers are invited on the following areas: *photovoltaics, thermoelectrics, electrochemical conversion, [etc.]. 1978Telegraph (Brisbane) 16 May 6/2 Photovoltaics is the dream form of solar power—a single cell without moving parts, silent, reliable and pollution free. 1978Nature 13 July 117/1 The United States administration is clearly determined to make a success of photovoltaics.
2. Words in which photo- indicates connexion with photography, or some photographic process; being sometimes (esp. in nonce-wds.) practically equivalent to photographic, as in photo-chart, photo-cyclist, photo-equipment, photo-miniature, photo-process, photo-revolver, photo-survey, photo-tracing, photo-transfer.
photo-ˈaquatint: see quots.; ˌphoto-bibliˈography, description of books by the aid of photography; ˈphoto-call, a summoning (cf. call n. 6 h) of theatrical performers or the like to be photographed; the session at which they are photographed; ˌphoto-ceˈramic a., ceramic (work) decorated by photographic processes; also as n. (pl.); hence photo-ˈceramist, an artist in photoceramic work; ˈphotoˌcharger, a device for photographically recording details of books loaned from a library; so ˈphotoˌcharging vbl. n.; ˌphotocliˈnometry [clino-], the process of deriving topographical information about a region from measurements of the brightness distribution in aerial photographs of it; photo-ˈcollotype: see quot.; photo-ˈcrayon a., produced by a photographic process giving the effect of crayons, or by crayon-work on a photographic groundwork: see quot.; ˌphoto-eˈlectrotype: see quot.; so ˌphoto-eˈlectrotyping; ˈphoto-ˌessay, an essay or short biography consisting of text matter and (numerous) photographs; photo-ˈetch v. trans., to etch by a photographic process, as in photogravure; ˈphoto-ˌetcher, one who employs a photographic process in etching; so photo-ˈetching; photofacˈsimile, facsimile in which the likeness is reproduced in photographic form; usu. attrib.; photo-ˈfiligrane: see quot.; photoˈfluorogram, a photograph of a fluoroscopic X-ray image; photoˈfluorograph n. = prec.; v. trans., to examine by photofluorography; ˌphotofluoˈrography, photography of a fluoroscopic X-ray image; hence ˌphotofluoroˈgraphic a., ˌphotofluoroˈgraphically adv.; photoˈfluoroscope, an instrument for taking photofluorograms; ˌphotofluoˈroscopy = photofluorography above; photoˈgastroscope, ‘an arrangement for photographing the inside of the stomach’ (Woodbury Encycl. Phot. 1892); photo-ˈgelatin a., applied to any photographic process in which gelatin is used; ˌphotogoniˈometer, (a) an instrument for measuring angles indirectly from photographs of an area; (b) an instrument for photographically recording the X-rays diffracted at known angles by a crystal or substance; hence ˌphotogonioˈmetric a., -goniˈometry; photoˈgraphotype, a method of producing blocks for letter-press printing by the aid of photography and electrotyping; photo-ˈhyalotype = hyalotype; ˌphoto-ˈink a., produced by photography so as to be printed in ink; ˌphoto-inˈtaglio |-ˈtɑːljəʊ|, a design in intaglio produced by a photographic process; also attrib.; ˌphotointerpreˈtation, the interpretation of aerial photographs; so photo-inˈterpreter; photoinˈterpretative, -inˈterpretive adjs.; photoˈjournalism, the use of photographs in journalism; so photoˈjournalist; photo-ˈlithotype, a picture produced by photolithography; ˈphoto-magazine, a magazine containing many photographs; ˈphotomap, a map consisting of or drawn on a photograph or photomosaic of the area concerned; photo-ˈmapping, the mapping (of the stars, etc.) by photography; so photo-ˈmapper, an instrument for this; ˌphoto-meˈtallograph, a photozincograph or analogous engraving; so ˌphoto-metaˈllography; photo-ˈmezzotype (also abbrev. photo-mezzo), a photo-mechanical printing process similar to collotype; a print produced by this; photomoˈsaic = mosaic n. 3 d; photoˈmural, a mural consisting of a photograph or photographs; photo-ˈnephograph [Gr. νέϕος cloud: see -graph], an apparatus for taking a succession of simultaneous photographs of a cloud from two points at some distance apart, in order to ascertain the height and movement of the cloud; also called photo-ˈnephoscope; photoˈnymograph Cartography [Aeolic Gr. ὄ-νυµ-α name], an instrument used in map production for producing printed names photographically; ˌphoto-paˈpyrograph, a plate or print made by ˌphoto-papyˈrography, a modification of photolithography, in which paper is used as the support, instead of a stone or a metal plate; ˈphotophane: see quot.; ˈphotoplate, a photographic plate (plate n. 5 c); ˈphoto-ˈprint, a print produced by a photo-mechanical process; so ˈphoto-ˈprinting; photoˈradiogram, a picture, diagram, or the like transmitted by radio; (formerly a proprietary name in the U.S.); ˈphoto-ˌrecce, colloq. abbrev. of next; photoreˈconnaissance, reconnaissance by means of aerial photography; ˈphoto-reˈlief, an image in relief produced by a photographic process; also attrib.; ˌphoto-reporˈtage = photojournalism above; also, a report that uses photographs; so ˈphoto-reporting; photo-ˈrocket: see quot.; ˈphotoscanning vbl. n. Med., photography of the pattern of radiation from the body following the internal administration of a radio-isotope (e.g. to locate tumours); so ˈphotoscan, a photograph so obtained; ˈphotoscanner, an apparatus for taking such photographs; photo-ˈsculpture n., a process in which the subject is photographed simultaneously from a number of different points of view all round, and the photographs are used to trace successive outlines on a block of modelling clay, which is afterwards finished by hand; hence photo-ˈsculptural a., pertaining to or produced by photo-sculpture; photo-ˈsculpture v. trans., to produce by photo-sculpture; ˌphoto-specˈtroscopy, the application of photography to spectroscopy; so ˌphoto-spectroˈscopic a., pertaining to photo-spectroscopy; photoˈstereogram, a stereophotograph; photoˈstereograph, an instrument for the observation, measurement, and interpretation of pairs of stereophotographs for surveying purposes; so ˌphotostereoˈgraphic a.; ˈphotoˌstory, a story with accompanying photographs; photo-ˈtelescope, a telescope with photographic apparatus, used for photographing stars or other heavenly bodies; ˌphoto-theˈodolite, an instrument for the performance of triangulation by means of photographs; ˈphoto-ˌtimer, (a) (see quot. 1942); (b) (see quot. 1949); ˈphototint, a photo-mechanical printing process similar to collotype, used c 1875 (Woodbury Encycl. Phot.); photo-ˈvitrotype [L. vitrum glass: see type], a photograph printed on glass; photo-xylography |-zaɪˈlɒgrəfɪ| [xylography], a process of employing photography in the preparation of wood blocks for printing from.
1892Woodbury Encycl. Phot. 503 *Photo-Aquatint, a process for printing pictures from intaglio copperplates. 1897Daily News 4 Oct. 6/4 The bichromate process, to which has been given the name ‘Photo-Aquatint’ because there is practically nothing used but pure water-colour fixed by the effect of light acting through a negative.
1878H. Stevens (title) *Photo-Bibliography, or a Word on Printed Card Catalogues of Old, Rare, Beautiful and Costly Books, etc., with reduced facsimiles of some famous Works issued during the Sixteenth and Seventeenth Centuries. 1891Athenæum 10 Jan. 53/2 The subject of photo-bibliography was one of his [H. Stevens's] pet hobbies.
1958L. Vining in Newnes Compl. Amat. Photogr. xx. 182 Theatre photography can be divided into two classes—*photo calls when you have control of the actors and lights, and photographing from the stalls during the performance, when you have no control of anything. 1966‘S. Harvester’ Treacherous Road i. 22 A string of camels kept motionless against the burnt yellow sky, well-trained as pop singers on a photo-call. 1971Times 8 Sept. 3 Sir Bernard, who plays Iago, promised that the official photocall next week would reveal all of Miss Stevenson, and a very lyrical and beautiful sight it would be. 1977J. Hedgecoe Photographer's Handbk. 93 Most photography of theatrical productions takes place under one of two distinct sets of conditions—during an actual public performance, or during a dress rehearsal or specially staged ‘photo-call’.
1895Daily News 9 May 3/6 The Princess of Wales has consented to lend her Collection of *Photo-Ceramics to the Exhibition of Photography.
1894Amer. Ann. Photog. 143 A *photo-ceramist of no ordinary merit.
1959L. M. Harrod Librarians' Gloss. (ed. 2) 208 *Photo-charger, an electrical machine for recording the loan of books on microfilm. 1967L. V. Paulin in W. L. Saunders Librarianship in Brit. Today i. 4 The introduction of more photochargers.
1955W. Ashworth Handbk. Special Librarianship xii. 319 Such devices as audio-charging..and *photo-charging..have been used in America in public libraries. 1967C. R. Eastwood Mobile Libraries ix. 94 Photocharging is widely used on American mobile libraries but not in Britain.
1894Athenæum 4 Aug. 165/3 Comparing the present *photo-charts [of stars] with others obtained by the same processes after the lapse of several years.
1967Surveyor III (U.S. Nat. Aeronaut. & Space Admin. SP-146) iii. 16 (caption) *Photoclinometric profiles of the Surveyor III landing site. Profiles were calculated from photometric measurements of Lunar Orbiter III photograph H154..(*photoclinometry by H. E. Holt and S. G. Priebe). 1974Nature 10 May 132/1 The development of inferred topography on the basis of the brightness distribution in the image of a surface exhibiting diffuse reflection, and a knowledge of the quantitative law of light scattering for the kind of surface under scrutiny, has been called photoclinometry by common agreement over the past few years. (The word ‘photoclinometry’ is due to J. F. McCauley...) An operational photoclinometric theory adapted to light scattering properties peculiar to the Moon was worked out..several years ago. 1975Times 18 June 2/2 A group..specializing in lunar and planetry sciences at Lancaster University..is using a method known as photoclinometry to measure the profiles and heights of hills, craters, ridges and cliffs [on Mercury]; the process depends on assessing subtle changes in brightness of the ground and rocks on the pictures.
1881Abney Photogr. 186 By a *photo-collotype process is meant a ‘surface printing’ process, by which prints are obtained from the surface of a film of gelatine, or other kindred substance.
1873E. Spon Workshop Receipts Ser. i. 270/1 *Photo-Crayon Portraits. 1892Woodbury Encycl. Phot. 503 Photo Crayon Process, a photographic transparency on glass..[was] afterwards backed up with white paper, on which a number of lines, hatchings, or stippling were lithographed, giving the portrait the appearance of a crayon work.
1898Westm. Gaz. 13 July 8/1 A *photo-decorated tile company in Staffordshire.
1875Knight Dict. Mech., *Photo-electrotype, a process in which a photographic picture is produced in relief so as to afford, by electro-deposition, a matrix for a cast, from which impressions in ink may be obtained.
1865in Abridgm. Specif. Patents, Photogr. (1872) 118 An improved *photo-electro⁓typing process.
1891Anthony's Photogr. Bull. IV. 427 A dozen African explorers could be fitted out with the now indispensable *photo-equipment.
1976Publishers Weekly 2 Aug. 104/1 Mexican landscape architect Luis Barragán..in a major book... Seven of his most characteristic works—each briefly prefaced and explored at length in a *photo-essay. Ibid. 4 Oct. 65/3 Seven sumptuous photo-essays (more than 300 pictures, many in color). 1977C. McFadden Serial (1978) ix. 24/2 Michael Bry would..do this photo essay on her.
1889*Photo-etch [see photo-engraving]. 1900Athenæum 21 July 92/1 The plates..have been photo-etched from the author's drawings.
1889Year Bk. Photogr. 158 One difficulty which *photo-etchers have to contend against in the City is the vibration caused by the incessant traffic.
1896Daily News 19 Dec. 3/5 A skilful *photo-etching..after the picture of ‘The Ferry’.
1959K. Henney Radio Engin. Handbk. (ed. 5) xxiii. 1 *Photofacsimile systems reproduce the subject copy on photographic papers or films. 1971Science 6 Aug. 529/2 These transmissions, known as the DRIR (direct readout infrared) data, can be displayed on a photofacsimile recorder, which produces a continuous strip image. 1973Nature 16 Feb. 434/2 His youthful German collaborator made a fair copy of Copernicus's precious autograph (now splendidly reproduced in photofacsimile).
1883Athenæum 27 Jan. 124/2 A new process..named ‘*photo-filigrane’, for producing the water-mark in paper by a photographic process.
1942Radiology XXXVIII. 453/2 The initial scrutiny of routine *photofluorograms by the staff radiologist will provide him with an objective means of determining which of all patients..should be referred for searching x-ray examination of the chest. 1975B. W. Gayler in E. J. Potchen Current Concepts in Radiol. II. vii. 131 For many years, mass survey and screening chest radiographs were taken as 70 mm photofluorograms.
1941Med. Jrnl. Austral. I. 267/2 The method of focusing is to make *photofluorographs of a wire mesh mounted immediately in front of the fluorescent screen holder. 1972Science 16 June 1186/3 The American public would be exposed to hundreds of thousands of unnecessary chest photofluorographs each year.
1945Amer. Jrnl. Roentgenology L. 405/2 A subject 20 cm. in thickness *photofluorographed with the roentgen machine operating at 90 kv. 1957Ibid. LXXVII. 1079/1, 101 persons were photofluorographed.
1941Med. Jrnl. Austral. I. 267/2 The four inches by five inches *photofluorographic unit incorporates a special 14 inches by 17 inches fluorescent screen. 1954Brit. Jrnl. Radiol. XXVII. 459/1 An attempt to reduce cost of routine examinations..by employing the photofluorographic method. 1972J. E. Cullinan Illustr. Guide X-Ray Technics i. 24/1 A photofluorographic unit is a quick, efficient way to accomplish mass survey chest radiography.
1949Amer. Jrnl. Roentgenology LXI. 186/1 All patients above the age of forty..will be examined *photofluorographically.
1941Med. Jrnl. Austral. I. 266/1 *Photofluorography opens up a new avenue of examination to the wage-earning class. 1974Encycl. Brit. Macropædia XV. 462/2 Photofluorography and television observation can take place simultaneously by means of separate apertures, and thus observation of what is being photographed is achieved.
1896J. M. Bleyer in N.Y. Med. Jrnl. LXIII. 540/1 The *photo-fluoroscope is an instrument which differs from all other fluoroscopes in the fact that it allows a direct shadow picture to be taken from the screen on the fluoroscope, after it is focused through the screen, and the image is seen on the ground glass in the photographic focusing box. 1933O. Glasser Sci. of Radiol. i. 10 J. M. Bleyer of New York built his photofluoroscope which was destined to become the predecessor of the roentgen moving picture camera. 1955G. L. Clark Appl. X-Rays (ed. 4) ix. 197 (heading) *Photofluoroscopy (indirect radiography). 1966McGraw-Hill Encycl. Sci. & Technol. XI. 302/2 The photography of the fluorescent image, as in mass chest examinations, is called photofluoroscopy.
1875Knight Dict. Mech., *Photo-gelatine Process, one in which gelatine, prepared chemically, usually by the bichromate of potash, is made to receive a photographic image.
1926A. W. Judge Stereoscopic Photogr. xviii. 218 The effect of tilting and swinging the plate in the *photogoniometer is such as to render the angular measurements..the same as if the view had been taken on a vertical plate. 1927Jrnl. Sci. Instruments IV. 273 (heading) A universal X-ray photogoniometer... Combining: apparatus for single crystal rotation photographs—Laue photographs—X-ray spectrometry—powder photographs—photographs of crystal aggregates, metals, materials, etc. 1933A. R. Hinks Maps & Survey (ed. 3) xii. 243 The machines which have been developed during the last few years all utilise..the principle of the Bildmesstheodolit, otherwise called the Photogoniometer, in which the plates are viewed through objectives identical with those which took them. 1939Geogr. Jrnl. XCIII. 150 The American Geographical Society first of all made a photogoniometer (Bild-Theodolit) on a somewhat novel principle. 1970Chem. Abstr. LXXIII. 305/2 A single-circle universal photogoniometer with vertical crystal-bearing attachment,..was devised.
1939Geogr. Jrnl. XCIII. 242 The first extensive photographic survey was that of the stars, made by Kapteyn..with a *photogoniometric machine he built about 1890. 1968Chem. Abstr. LXIX. 6626/2 (heading) Photogoniometric investigation of a crystal surface. Ibid., A goniometric study of crystals is rarely made because labs. often have no goniometer. The goniometric method in many cases can be replaced by photogoniometry.
1939B. B. Talley Engin. Applic. Aerial & Terrestr. Photogrammetry ii. 9 (caption) *Photogoniometry by the method of Porro and Koppe.
1874(title) Specimens of *Photo-Graphotype Engraving.
1875Knight Dict. Mech., *Photo-hyalotype.
1888Athenæum 14 July 69 Reproduced, with no remarkable success, by the *photo-ink process.
1875Knight Dict. Mech., *Photo⁓intaglio Engraving, a process in which, by photographic means, lines are etched in a plate to be subsequently filled with ink and printed by the copperplate printing-press. 1891Anthony's Photogr. Bull. IV. 181 An early photo-intaglio process.
1923Photogrammetric Engin. VIII. 27 The..function of exploiting and developing the intelligence from the aerial photos falls within the sphere of *photo interpretation units. 1959Proc. Geologists' Assoc. LXX. 144 It may be necessary..to complete a preliminary photo-interpretation before planning ground traverses. 1966Daily Tel. 20 Aug. 14/5 These pictures will form stereo-pairs and can be analysed by standard techniques of photo-interpretation to give maximum information about the terrain on which American astronauts may land. 1973Sci. Amer. Feb. 21/2 The cost of hardware and manpower for photo⁓interpretation..will remain high.
1959Proc. Geologists' Assoc. LXX. 144 The best practice is a judicious combination of *photo-interpretative methods and geological field mapping.
1942Photogrammetric Engin. VIII. 26 While the aerial camera sees all, it is the *photo interpreter who must know all and tell all. 1957Ibid. XXIII. 933 A mathematical proof is presented for the statement that differential parallaxes smaller than 0·001 inch cannot be detected by average photo-interpreters. 1977Sci. Amer. Sept. 57/1 Only the wide curve it must make on slopes betrays it to the photointerpreter.
1967Boston Sunday Herald 26 Mar. (Comic Section), I subjected the film to the usual *photo-interpretive analysis.
1944K. Hubschmann in A. Kraszna-Krausz Photogr. as Career 118 My friend proved an excellent teacher of the essentials of *photo-journalism. 1958M. F. Harker in Newnes Compl. Amat. Photogr. xiii. 140 The present trend of photo-journalism which attempts to put over human stories in pictures rather than words. 1976National Observer (U.S.) 11 Sept. 20/1 This colorful chap is Nelson Wadsworth, who teaches photojournalism, magazine writing, and investigative reporting at Brigham Young University in Utah. 1977Time 12 Dec. 60/2 World War II was the longest-running story in the history of Life, the magazine that practically invented photojournalism.
1959C. B. Neblette Photogr. Lens Manual ii. 25 After the 50 mm, the 35 mm medium wide-angle, or wide-field lens is undoubtedly the most useful to..the *photojournalist. 1963A. E. Woolley Creative 35mm Techniques III. 113/2 At all times a photojournalist is aware of the maximum emotion or conflict of the subject of the story. 1974Nat. Geographic Aug. 252 At last I am here in North Korea, the first American photojournalist to gain entry into a country cloistered from the non-Communist world for a quarter of a century. 1978New York 3 Apr. 32/3 Micha Bar Am/Harold Edgerton/Frank Rinehart—Begin and Sadat by this Mid-East photojournalist.
1859Sat. Rev. 26 Feb. 243/1 A process well worth attention..its result may be called a *Photo-litho-type.
1960News Chron. 10 Oct. 4/1 Paris-Match, the most powerful *photo⁓magazine in Europe. 1969Amat. Photographer 28 May 26/3 Few of the present-day casual photographers and snapshotters do their own processing. The photographic trade and the photo-magazines do not encourage it.
1939B. B. Talley Engin. Applic. Aerial & Terrestr. Photogrammetry xix. 521 When this becomes economically feasible encouragement should be given to the development of ‘*photo-maps’ to which may be added contours. 1955Times 1 Aug. 6/1 The first 200 photographic sky charts..are being sent to observatories all over the world, and when the atlas is completed in 1956 it will include 1,758 such ‘photomaps’. 1969Nature 16 Aug. 668/1 (caption) Satellite photomap of the Tucson, Arizona, area with transport network superimposed. The map is based on a photograph taken..from Gemini V.
1870H. M. Parkhurst Amer. Jrnl. Sci. Ser. ii. XLIX. 38 The motion of the diaphragm may be produced..by the star-key of my star-mapper; and this constitutes the *Photo-mapper.
Ibid. 39 In *photo-mapping I place the prism always in the meridian. 1899Daily News 6 June 8/4 The photo⁓mapping of the heavens by the Astrographic Equatorial.
1875Knight Dict. Mech., *Photo-metallograph, see Photo⁓zincograph.
1859Sat. Rev. 26 Feb. 242/2 *Photo-metallography.
1890Pall Mall G. 4 Aug. 6/2 A *photomezzotype of Mrs. General Booth. 1891Anthony's Photogr. Bull. IV. 428 That perfected form of collotype which the company has christened ‘photomezzotype’. 1893Nation (N.Y.) 13 July 34/1 The..photomezzotype plates give us pictures of the Great Barrier Reef..of the greatest beauty.
1958New Scientist 13 Nov. 1247/3 The *photomosaic is being assembled now. 1962Times 17 May 10/3 The leading aircraft, navigating on a photo-mosaic. 1973Sci. Amer. Dec. 132/3 This is the planet Mars, drawn from Mariner 9 photomosaics. 1977Time 17 Oct. 45/1 Among the pictures released by NASA: a photomosaic of the planet's north pole, showing a concentric pattern of striations in the ice cap.
1935W. D. Morgan et al. Leica Manual 469 (caption) *Photomurals with the Leica. 1937Archit. Rev. LXXXI. 86 The true photo-mural... This new process of mural decoration, which can now be said to have passed the experimental stage, has its chief virtue in that the design is projected direct on to the wall surface. The surface is first sprayed with photo-sensitive emulsion, and the photograph printed on it much in the same way as an ordinary camera enlargement. 1960House & Garden Oct. 65/1 For ease of hanging, these photomurals are printed on lightweight white base paper. 1976National Observer (U.S.) 24 Apr. 24/2 Once inside, the visitor encounters giant photomurals, three-quarter mock-ups of building exteriors, [etc.].
1890Athenæum 29 Mar. 408/2 Reference was..made to Mr. J. B. Jordan's form of sunshine recorder, and to Capt. Abney's *photo-nephograph.
1933J. S. A. Salt Simple Method Surveying from Air Photogr. xi. 130 The names..are printed photographically in a *Photonymograph... Names may be printed in a variety of sizes and styles on a strip of sensitized paper. The alphabet..and any other signs..are contained on a master-disc. With the disc in position, each letter in turn is brought into position and an exposure made... The strips are developed and fixed..and then show a series of names in various sizes and styles. 1963Record (Oxf. Univ. Press) Dec. 2/3 The Drawing Office has installed a ‘photonymograph’ (a device whose development was in fact sponsored by the Cartographic section) to produce its lettering and so free draughtsmen for drawing. 1971Monkhouse & Wilkinson Maps & Diagrams (ed. 3) i. 64 The new model..of the Photonymograph (developed from a machine which appeared in its earliest form over thirty years ago) is made by Barr and Stroud, Ltd.
1862Catal. Internat. Exhib. II. xiv. 53 Plans reduced by photography, photozincographs, and *photopapyrographs.
1862Scott & James Photo-zincography Pref. 6 The discovery of the art of *Photo-papyrography was the result of an accident.
1889Anthony's Photogr. Bull. II. 427 *Photophane is a photo-mechanical process allied (but superior) to collotype.
1918Physical Rev. XI. 137 (heading) Images on silvered *photo-plate. 1974Nature 20 Dec. 698/2 Organochlorine compounds may be identified at low concentrations in crude extracts of natural samples by a high resolution mass spectrometric method involving photoplate detection.
1888Ld. R. Gower (title) ‘Bric-a-brac’, or some *Photoprints illustrating Art Objects at Gower Lodge, Windsor. 1889Athenæum 20 July 91/2 The book is embellished with six photoprint illustrations.
1884Knight Dict. Mech. Supp., *Photo-printing Process.
1875Ibid., *Photo-processes. 1897Daily News 1 Apr. 5/4 Photo-process classes for the instruction of all comers actually engaged in any branch of the photo-mechanical, photographic, designing, lithographic, engraving, and printing crafts.
1924Glasgow Herald 13 Dec. 9 The signature was that of Sir Robert Kindersley, whose *photo-radiogram read—‘My warmest greetings.—R. M. Kindersley.’ The message and signature accompanied a radio photo of Sir Robert. 1925Official Gaz. (U.S. Patent Office) 26 May 803/1 Radio⁓corporation of America, New York, N.Y. Filed Jan. 13, 1925. Photoradiogram... Pictures, drawings, and facsimiles transmitted by radio. Claims use since Nov. 30, 1924. 1926Daily News 1 May 5/6 Most of the photoradiograms sent from this side during the night will appear in American newspapers today. 1927Daily Express 16 Dec. 1, December 21 is the latest date for handing in Christmas photo-radiograms at Marconi offices. 1946War Report (B.B.C.) vi. 149 Then on Sunday evening one of our *photo-recce Spitfires was shot down in German territory. 1971N.Y. Times 13 June iv. 37 We have a high priority requirement for night photorecce of key motorable routes in Laos.
1944Sci. News Let. 19 Aug. 117/3 *Photo reconnaissance supplies information regarding the strength of enemy troops. 1951A. C. Clarke Sands of Mars xvi. 209 I'm going to suggest a photo⁓reconnaissance of all the..forests. 1973Sci. Amer. Feb. 14/2 The main restrictions imposed by both of the SALT I agreements can be..monitored largely by means of sensors carried on board such orbiting photoreconnaissance systems.
1875tr. Vogel's Chem. Light xv. 230 The Production of *Photo-Reliefs. 1881Abney Photogr. xxvii. 186 Mr. Dallas..has produced photo-relief blocks for the reproduction of half-tone prints. 1892Woodbury Encycl. Phot. 538 The Woodbury process is often termed a photo-relief one.
1960Spectator 17 June 886 The great *photo-reportage magazines have now..largely relinquished their commanding position to television. 1960L. Durrell Spirit of Place (1969) 162, I remember seeing a photo-reportage in Life magazine once which dealt with the extraordinary changes in physique which immigrants to the U.S.A. underwent. 1966Punch 6 Apr. 498/1 One of the many technical hazards which are endemic in photo-reportage are bound to materialise in full force.
1957T. L. J. Bentley Man. Miniature Camera (ed. 5) iv. 41 The few models which incorporate a motor drive create totally new possibilities of rapid-sequence pictures which may be quite invaluable in..records of sporting events and *photo-reporting for journalistic purposes.
1886Pall Mall G. 4 Oct. 10/1 Instantaneous photographs of Russian life, taken by the *photo-revolver invented by K. Brandil, photographer to the Warsaw Imperial University.
1889Pall Mall G. 11 Jan. 6/2 A curious photographic apparatus, in which a camera is raised by a rocket and lowered by a parachute... For securing bird's-eye views the *photo-rocket offers several important advantages over balloon photography.
1956Radiol. LXVI. 737/2 (heading) *Photoscan (superimposed on roentgenogram) shows lesion to be thyroid tissue rather than metastasis from breast. 1974Cancer Res. XXXIV. 1/1 The photoscans showed an increased uptake of radioactivity over the tumors.
1959Internat. Jrnl. Appl. Radiation & Isotopes IV. 154 (heading) A versatile, high-contrast *photoscanner for the localization of human tumors with radioisotopes. 1966Sci. News 12 Nov. 400 The gamma rays coming from the abnormal portions of bone are detected by a photoscanner that is passed externally over the body. Any portion of bone that gives off gamma rays is considered diseased. X-rays, in contrast, work by showing changes in bone density.
1956Internat. Jrnl. Appl. Radiation & Isotopes I. 137/1 A *photo scanning device has been devised which presents a 150% increase in picture density as the result of a 10% increase in count rate. 1967Times 19 Sept. 9 Photo⁓scanning using radioactive isotopes can tell us if cancer is present in such organs as the thyroid gland, the liver and the brain. 1974Cancer Res. XXXIV. 1/1 Radiolabeled nonantibody components of heterospecific IgG can be localized in certain tumors and normal tissues by photoscanning.
1883Pall Mall G. 6 Dec. 5/1 Comparing some of the originals with the *photosculptural copies.
1863in Abridgm. Specif. Patents, Photogr. (1872) 70 [This invention (of François Willèms) relates to] *photo-sculpture. 1864Round Table 18 June 12/2 Busts and figures in clay, modeled by a new process called Photosculpture, exhibiting a new and charming development of heliographic art. 1875tr. Vogel's Chem. Light xv. 231 This photo-sculpture, as it is called, can only be carried out imperfectly.
1881Abney Photogr. 282 The spectroscope and camera are rigidly connected one with another... This completes the *photo⁓spectroscopic arrangement.
Ibid. 263 *Photo-spectroscopy..has two aspects: in one it is the study as to the sensitiveness of compounds to the influence of different portions of the spectrum; in the other, the study of the spectrum itself.
1913Chem. Abstr. VII. 3862 App[aratus] for copying the surface of a solid body from a *photostereogram. 1939B. B. Talley Engin. Applic. Aerial & Terrestr. Photogrammetry xix. 526 (caption) The Nistri *photostereograph. 1963W. K. Kilford Elem. Air Survey xi. 265 (caption) The photostereograph (Beta/2) coupled with coordinate computer on the left and plotting table and coordinate plotter on right.
1933A. R. Hinks Maps & Survey (ed. 3) xii. 243 (heading) Recent developments in *photostereographic surveying. 1940War Illustr. 19 Jan. 627 (heading) *Photo-story of the life and death of a U-boat. 1972Guardian 24 Mar. 12/6 The photo-story in 7 Days left one with a powerful impression. 1973D. Matias tr. C. Metz in Screen Spring/Summer 197 Image-languages..figurative drawing,..television, photography, the photo-story etc.
1891Anthony's Photogr. Bull. IV. 236 Join a society which has undertaken the ‘*photo-survey’ of its district, and do your part.
1893Fichel in Chatauquan XIII. 318 The photo-connecting lens of 33 inch diameter being placed over the 36 inch telescope, thus turning it into a *phototelescope. 1894Athenæum 10 Feb. 183/2 The Compton 8-inch photo⁓telescope has been used for photographing stars suspected of variation.
1892Ibid. 5 Mar. 311/3 A *photo-theodolite, an instrument equally well adapted for geodetic and astronomical measurements, and invaluable for taking panoramic views of mountain regions.
1942Amer. Jrnl. Roentgenology LXVIII. 220/1 A new instrument, a photoelectric timing mechanism, capable of regulating automatically the length of roentgenographic exposure time has been developed... The photoelectric timing mechanism, or *phototimer, is a modification of the roentgenographic exposure meter. 1949Britannica Bk. of Year 687/2 Photo-timer, an electrical device which photographs the finish of a race and supplies the elapsed time from start to finish. 1958Times 22 Aug. 4/1 The race..should be started farther back from the bend, in spite of the cost of moving the electrical photo-timer.
1892Woodbury Encycl. Phot. 531 A little *photo-transfer ink is mixed with turpentine.
1875Knight Dict. Mech., *Photo-vitrotype.
1865Chambers's Encycl. VII. 510/1 *Photo-Xylography, is the application of photography to wood-engraving.
3. Prefixed to the names of chemical salts, etc., and of chemical processes, to express the effect of light in changing the molecular constitution of the salt, etc. (by virtue of which it is capable of being employed in photography). Thus: ˌphoto-decompoˈsition, decomposition due to the action of light; ˌphotodegraˈdation, degradation of a substance caused by light; so photodeˈgradable a.; photoˈdimer Chem., a dimer formed by photochemical action; so photodiˈmeric a.; also ˌphotodimeriˈzation, the formation of, or conversion into, a photodimer; photoˈdimerize v. trans. and intr., to dimerize by the action of light; ˌphotodissociˈation Chem., dissociation of a chemical compound by the action of light; so photodiˈssociate v. trans., to dissociate by means of light; photo-oxiˈdation, oxidation due to the action of light; photo-ˈoxidative a., involving or characterized by photo-oxidation; photo-ˈoxidize v. trans., to oxidize photochemically; hence photo-ˈoxidizable a., -ˈoxidized ppl. a.; ˌphotophosphoryˈlation Biochem., the process by which light energy is utilized by a plant or micro-organism to convert adenosine diphosphate to adenosine triphosphate without the reduction of oxygen to water that occurs in oxidative phosphorylation; photoˈpolymer, a polymer produced photochemically; ˌphotopolymeriˈzation Chem., polymerization brought about by the action of light; so photoˈpolymerize v. trans., to polymerize photochemically; photoˈpolymerized ppl. a.; also photoˈpolymerizable a., capable of being photopolymerized; ˌphotopolymerizaˈbility; ˈphoto-ˈsalt, a general term for any salt modified by light; so photo-bromide, photo-chloride, photo-iodide, photo-sulphate, etc.
1888Chem. Photogr. (1889) 52 It is known that moisture accelerates the photo-decomposition.
1972New Scientist 5 Oct. 41/2 (heading) Photo-degradable plastic carriers. 1975Rånby & Rabek Photodegradation ix. 361 The development of methods for making plastics which are photodegradable to form harmless and biologically useful chemical compounds is of great interest.
1962J. T. Marsh Self-Smoothing Fabrics xviii. 303 The resin exerts a considerable protective influence even in presence of those vat dyes whose action accelerates photo-degradation of cellulose. 1975Physics Bull. Apr. 164/1 (Advt.), The fundamental photochemical reactions involved in photodegradation of polymers.
1936Trans. Faraday Soc. XXXII. 521 The photodimer of thiophosgene. 1970J. B. Birks Photophysics of Aromatic Molecules vii. 322 If..photodimers of other anthracene derivatives are irradiated with ultraviolet photons of sufficient energy..photolysis occurs and the dimer reverts to the original pair of individual molecules.
1952Chem. Rev. LI. 19 The nonoccurrence of the photodimeric products of the previously mentioned anthracene derivatives is probably due to their thermolability.
1936Trans. Faraday Soc. XXXII. 517 A photodimerisation of 9–10-diphenyl anthracene has not yet been observed. 1972DePuy & Chapman Molec. Reactions & Photochem. iv. 65 Naphthalenes, anthracenes, and polyacenes in general undergo photodimerization.
1955Jrnl. Chem. Soc. 315, 3-Bromothionaphthen 1:1-dioxide was photodimerised in order to ascertain whether angular..or linear dimerisation was favoured. 1969Organic Photochem. II. 75 Acyclic α, β-unsaturated ketones photodimerize when substituted with an aromatic group in the beta position. 1970J. B. Birks Photophysics of Aromatic Molecules vii. 321 There are a large group of other 9-substituted and 9, 10-disubstituted anthracenes which also photodimerize.
1962F. I. Ordway et al. Basic Astronautics vi. 249 Water vapor is constantly being photodissociated by the action of sunlight. 1969Nature 22 Nov. 756/2 NH3, H2O and H2CO can all be photodissociated by ultraviolet photons of E
1925Phil. Mag. XLIX. 1166 It becomes of interest..to investigate the relation between the activation, and the frequency of the illumination;..only recently has a similar investigation been made on the photo-dissociation of sulphur dioxide. 1974Sci. Amer. June 29/1 Atomic iodine is prepared in the proper excited state by the photodissociation of gaseous compounds such as iodotrifluoromethane (CF3I) with xenon flash lamps. 1977Jrnl. R. Soc. Arts CXXV. 766/2 The high spectral brightness of lasers can be used resonantly to obtain selective photodissociation.
1888Chem. Photogr. (1889) 269 The photo⁓oxidation of lead compounds, of mercurous oxide,..and of sulphides, proceeds more rapidly in the red than in the violet rays.
1941Jrnl. Gen. Physiol. XXV. 309 The ultimate cause of the extra oxygen absorption after or during irradiation consists of photoxidation processes sensitized mainly by chlorophyll. 1956Nature 17 Mar. 513/2 The Bituminous Binder Research Unit has completed a preliminary investigation of photo-oxidation in the weathering of binders on the road. 1971Jrnl. Oil & Colour Chemists' Assoc. LIV. 846 Bleaching by sunlight may be due to photo-oxidation of double bonds.
1937Ann. Rep. Progr. Chem. XXXIII. 431 There is little doubt that this element [sc. manganese] can affect the chlorophyll content of leaves, and probably also its photo-oxidative properties. 1976Nature 13 May 169/2 A film exposed under high vacuum showed a dose response almost identical to that of one exposed in air, and indicates the photolytic rather than the photo-oxidative nature of the process.
1949Chem. Abstr. XLIII. 5391 (heading) Photoöxidizable derivatives of helianthrene. 1974Photochem. & Photobiol. XIX. 35/1 Dye-sensitized photo-oxidation..permitting preferential destruction of the photo-oxidizable amino-acid residues of proteins.
1941Adv. Enzymol. I. 232 Artificially added substances whose oxidation products can be recognized by their color are actually photo-oxidized in plants. 1975Nature 9 Oct. 490/2 It seems that O. limnetica photo-oxidises S2- quantitatively to S0.
1973Biochem. XII. 2540/2 The tryptophan content of the native and the photooxidized enzyme was measured.
[1954D. I. Arnon et al. in Nature 28 Aug. 394/1 Evidence has now been obtained that whole chloroplasts..have the ability to carry out..photosynthetic phosphorylation, a term which we use for the conversion of light energy into the high-energy phosphate bonds of adenosine triphosphate (ATP), without the participation of respiration.] 1956Plant Physiol. XXXI. p. xxx/2 (heading) The mechanism of cell-free, bacterial photophosphorylation. 1956Federation Proc. XV. 260/2 Photophosphorylation depends upon an inductive reduction. 1971M. F. Mallette et al. Introd. Biochem. xviii. 646 Photosystem 1, the longer wave length photosystem, has been associated with the reduction of NADP+ and with photophosphorylation. Photosystem 2 is related to dissociation of water and the evolution of oxygen. 1973R. G. Krueger et al. Introd. Microbiol. viii. 271/1 Photophosphorylation occurs in the reduction of cytochrome c with the generation of ATP from ADP and inorganic phosphate. The electron initially emitted from chlorophyll is ultimately returned to chlorophyll in a cyclic fashion; hence, the entire process of converting light energy to ATP (chemical energy) is termed cyclic phosphorylation... In plants and algae, a noncyclic type of photophosphorylation also occurs.
1932Canad. Jrnl. Res. VII. 479 The photo-polymer of vinyl butyl ether was purified. 1953Jrnl. Res. Nat. Bureau of Standards (U.S.) LI. 327 Teflon and tetrafluoroethylene photopolymers, on pyrolysis in a vacuum at 423·5° to 513·0° C, yield almost 100 percent of monomer. 1961Printing News 16 Feb. 10 The first complete 4-colour magazine to be produced from ‘Dycril’ photo-polymer (light-sensitive plastic) printing plates. 1974Clarendonian XXVIII. i. 41 There are plans afoot to convert other letterpress ‘classics’ to this type of plate should photopolymers prove the equal of our now traditional hot-moulded plastic plates.
1932Canad. Jrnl. Res. VII. 473 The photo-polymerizability is practically the same as that of the butyl ether. Ibid., Comparison with the closely related vinyl esters.. shows that, in the absence of catalysts, the latter are much more readily photo- and thermo-polymerizable. 1973Materials & Technol. VI. ix. 664 The photopolymerisable amide-compositions are used for the production of letterpress printing plates.
1920Chem. Abstr. XIV. 4427/1 (Index), Photopolymerization. 1924Jrnl. Amer. Chem. Soc. XLVI. 1614 It is concluded that in the photopolymerization of anthracene, a single molecule is activated by absorption of blue light and then proceeds to react with an unactivated molecule to form the polymer. 1970H. L. Needles in R. F. Reinisch Photochem. Macromolecules 129 Both oxygen and hydrogen donors effect riboflavin-sensitized photopolymerizations of aqueous acrylamide.
1921Jrnl. Chem. Soc. CXIX. 1028 Whether the same explanation does not apply to all carbohydrates and to chlorophyll, namely, that under the influence of light of very short wave-length they are decomposed to carbon dioxide, which is photosynthesised to formaldehyde, and this in its turn photopolymerised to sugars. 1933Jrnl. Amer. Chem. Soc. LV. 577 Ethyl acetate does not react with Wijs solution; nor does the polymerized product, since..solid photopolymerized vinyl acetate gave iodine values as low as 9·5 and 6·3, corresponding to 96 and 98% polymerized. 1974Sci. Amer. Oct. 119/2 They are made by first crystallizing the molecules of an appropriate monomer and then photopolymerizing the monomer crystal with ultra-violet light or gamma rays.
1887Carey Lea in Amer. Jrnl. Sc. 352 As these substances have been hitherto seen only in the impure form in which they are produced by the continued action of light on the normal salts, it might be convenient to call them photosalts, photochloride, photobromide, and photoiodide, instead of red or coloured chloride, etc.
1890Anthony's Photogr. Bull. III. 395 Photo⁓sulphate of iron solution was for a long time the only developer used.
Add:[1.] photoaˈcoustic a. Physical Chem. = optoacoustic a.
1970Soviet Physics: Semiconductors III. 1129/1 These experimental data do not demonstrate clearly the influence of lattice defects on the structure of the *photoacoustic absorption spectra. 1981Nature 9 July 180/3 The photoacoustic effect (prior to 1977 more commonly termed the optoacoustic effect) provides the basis for a calorimetric method of measuring the absorption of electromagnetic radiation by a sample under study.
ˌphotoˌchemoˈtherapy Med., the combined use of drugs and (usu. ultraviolet) light to treat a condition.
1974J. A. Parrish et al. in New Eng. Jrnl. Med. 5 Dec. 1210/2 Oral methoxsalen and long wave ultraviolet light is a form of chemotherapy. The term ‘*photochemotherapy’ is suggested to describe the interaction of light and drug that results in a beneficial effect on disease. 1976Lancet 11 Dec. 1281/2 It is wrong to say that topical idoxuridine is the only treatment of any value in herpes-simplex infections; photochemotherapy with neutral-red and other dyes is also effective. 1985Brit. Med. Jrnl. 14 Sept. 706/1 He had suffered from the condition for over 20 years and had received various topical treatments and photochemotherapy.
[2.] ˌphotoˈcollage, a technique of collage using (parts of) photographs or photographic negatives; a work of art made in this way; cf. photomontage n.
1967H. Stevens Design in Photo-Collage 7/1 The ability to turn the unbelievable into the believable makes *photo-collage a thoroughly enjoyable technique. 1975New Yorker 14 Apr. 74/3 A similar objectification of the Freudian dream work is achieved by Ernst in his photocollage, paint-scraping, and dripped-paint compositions. 1988Creative Rev. Jan. 3/3 David Hockney broke the rules of photography and art with his photo-collages.
photoˈmatrix (pl. photoˈmatrices) Typogr., (any of) a set of photographic images of characters used in electronic typesetting.
1958Bookseller 22 Feb. 948/1 Penguins make history in March by publishing the first book produced in England entirely without the use of metal type... In this new method of composition ‘*photo-matrices’ are assembled into lines on a normal keyboard. 1977M. H. Bruno in J. M. Sturge Weblette's Handbk. Photogr. & Reprogr. (ed. 7) xviii. 483/2 Phototypesetter models commonly used all share the principle of imaging from some kind of negative photo-matrix that holds an assortment of characters in a number of different typeface designs or fonts. 1987Chicago Tribune 18 Dec. VII. 130/5 My original photo matrices serve as the warp on which I weave my complex images.
ˈphotoˌnovel [cf. Sp. fotonovela], a magazine or other publication containing a (usu. romantic) story told in a sequence of photographs to which dialogue is added in superimposed speech balloons; an illustrated story of this type; also photo-novelette.
1963Economist 30 Nov. 918/2 Illustrated weeklies, *photo-novelettes, comics and women's magazines. 1978Daily News (N.Y.) 11 July 40/1 *Photonovels are here... These photonovels are the American counterparts of magazines that have been raging successes in Europe for decades. 1989Time 30 Jan. 68/2 He came to Madrid at 17, fronted a rock band, wrote a porno photo-novel, and for a decade worked for the state phone company.
▸ photodecompose v. Chem. (a) trans., to cause to decompose by the action of light; = photolyse v. 1; (b) intr., to undergo photodecomposition; = photolyse v. 2.
1940Proc. Royal Soc. (A.) 175207 It is shown by utilizing the para-hydrogen conversion that *photodecomposing ammonia has no effect on the stationary hydrogen atom concentration of the conversion. 1981Jrnl. Agric. & Food Chem. 29 125 This acid photodecomposed more slowly to carbon dioxide, chloride, and unidentified organic fragments. 1996FEBS Lett. 396243 Under irradiation at 312 nm, the molecule is photodecomposed. 2001Chem. Engin. (Nexis) 1 May 59 When linked up with the metal and exposed to ultraviolet light, the pollutants photodecompose 35, 120 and 164 times faster, respectively. |