MCGRAW-Hill
`ICTIONAHY Of
`CllNTlflC AND
`ICHNICAl
`IRMS
`fifth Edition
`
`Sybil P. Parker
`Editor in Chief
`
`McGraw-Hill, Inc.
`New York
`San Francisco
`Washington, D.C.
`Lisbon
`London
`Madrid
`Caracas
`Bogota
`San Juan
`Singapore
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`
`Milan
`Mexico City
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`
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`Montreal
`
`

`

`On the cover: Photomicrograph of crystals of vitamin 8 1 ,
`(Dennis Kunkel, University of Hawaii)
`
`Included in this Dictionary are definitions which have been published previously in the following works: P. B.
`Jordain, Condensed Computer Encyclopedia, Copyright © 1969 by McGraw-Hill, Inc. All rights reserved. J.
`Markus, Electronics and Nucleonics Dictionary, 4th ed., Copyright © 1960, 1966, 1978 by McGraw-Hili, Inc.
`All rights reserved. J. Quick, Artists' and l/Iustrators' Encyclopedia, Copyright © 1969 by McGraw-Hill, Inc. All
`rights reserved. Blakiston's Gould Medical Dictionary, 3d ed., Copyright © 1956, 1972 by McGraw-Hill, Inc. All
`rights reserved. T. Baumeister and L. S. Marks, eds., Standard Handbook for Mechanical Engineers, 7th ed.,
`Copyright © 1958, 1967 by McGraw-Hill, Inc. All rights reserved.
`
`In addition, material has been drawn from the following references: R. E. Huschke, Glossary of Meteorology,
`American Meteorological Society, 1959; U.S. Air Force Glossary of Standardized Terms, AF Manual II-I, vol.
`1,1972; Communications-Elecrronics Terminology, AF Manual II-I, vol. 3,1970; W. H. Allen, ed., Dictionary
`of Technical Terms for Aerospace Use, 1st ed., National Aeronautics and Space Administration, 1965; J. M.
`Gilliland, Solar-Terrestrial Physics: A Glossary of Terms and Abbreviations, Royal Aircraft Establishment Tech­
`nical Report 67158. 1967; Glossary ofAir Traffic Control Terms. Federal Aviation Agency; A Glossary of Range
`Terminology. White Sands Missile Range, New Mexico, National Bureau of Standards, AD 467-424; A DOD
`Glossary ofMapping. Charting and Geodetic Terms, 1st ed., Department of Defense, 1967; P. W. Thrush, compo
`and ed.,A Dictionary ofMining , Mineral, andRelatedTerms. Bureau of Mines, 1968; Nuclear Terms: A Glossary,
`2d ed., Atomic Energy Commission; F. Casey, ed., Compilation of Terms in Information Sciences Technology,
`Federal Council for Science and TechnOlogy, 1970; Glossary ofStinfo Terminology, Office of Aerospace Research,
`U.S. Air Force, 1963; Naval Dictionary of Electronic, Technical, and Imperative Terms, Bureau of Naval Person­
`nel, 1962; ADP Glossary, Department of the Navy, NAVSO P-3097.
`
`McGRAW-HILL DICTIONARY OF SCIENTIFIC AND TECHNICAL TERMS,
`Fifth Edition
`Copyright © 1994, 1989, 1984, 1978, 1976, 1974 by McGraw-HilI, Inc. All rights reserved. Printed in the United
`States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication
`may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without
`the prior written permission of the publisher.
`
`234567890
`
`DOW/DOW
`
`9987654
`
`ISBN 0-07-042333-4
`
`Library of Congress Cataloging-in-Publication Data
`
`McGraw-Hili dictionary of scientific and technical terms /
`Sybil P. Parker, editor in chief..-5th ed.
`p.
`cm.
`ISBN 0-07-042333-4
`I. Science-Dictionaries. 2. Technology-Dictionaries.
`I. Parker, Sybil P.
`Q123.M34 1993
`503-dc20
`
`93-34772
`CIP
`
`INTERNATIONAL EDITION
`
`Copyright © 1994. Exclusive rights by McGraw-Hili, Inc. for manufacture and export. This book cannot be re­
`exported from the country to which it is consigned by McGraw-Hill. The International Edition is not available in
`North America.
`
`When ordering this title, use ISBN 0-07-113584-7.
`
`

`

`Jlation
`
`modulus of rupture in bending
`
`1285
`
`;orne characteristics of a carrier.
`
`('maj-::I,lad-ilJ 'sig­
`
`[COMMUN] The process or the result of the pro­
`ion
`which some parameter of one wave is varied in accor­
`'ith some parameter of another wave.
`[MECH ENG]
`on of the fuel-air mixture to a burner in response to
`ons of load on a boiler. {,maj-::I'la-sh::ln}
`ion capability [ELECTR] Of an aural transmitter, the
`m percentage modulation that can be obtained without
`f ,maj-::I'la'sh::ln ,ka'p::l­
`Ig a given distortion figure.
`I
`Ion code [COMMUN] A code used to cause variations
`il in accordance with a predetermined scheme; normally
`lteror modulate a carrier wave to transmit data. I,maj'
`I
`1 ,kOd I
`ion crest [CO~MUN] The peak amplitude of an am­
`nodulated wav~. I ,maj'::I'la'sh::ln 'krest J
`ion-doped field-effect transistor See high-electron
`transistor.
`(imaj-::I'la'sh::ln ;dopt 'reid i;fekt tran'zis'
`
`[SOLID STATE] An epitaxially
`
`ion-doped str\lcture
`,),stal structure ,n which successive semiconductor lay­
`
`[,maj'::I'Ia'
`
`lin different types of electrical dopants.
`pt 'str~k'Cher l'
`
`;onenvelope '[COMMUN) A curve drawn through the
`
`a graph showiog the waveform of a modulated signal;
`
`ts the waveform of the intelligence carried by the signal.
`
`lii'Shoo 'en'v::l,lop I
`
`ion factor
`[COMMUN] 1. In general, the ratio of the
`
`iation in the modulation actually used in a transmitter
`
`laximum variation for which the transmitter was de­
`2. In an amplitude-modulated wave, the ratio (usually
`din percent) of the peak variation of the envelope from
`nee value, to the reference value. Also known as index
`lation. 3. In a frequency-modulated wave, the ratio of
`llfrequency swing to the frequency swing required for
`I ,maj·;;.'la·sh::ln ,fak·t::lr I
`odulation.
`Ion Index
`[COMMUN] The ralio of the frequency de­
`othe frequency ,of the modulating wave in a frequency­
`ion system when using a sinusoidal modulating wave.
`lwn as ratio deViation. {,maj·;;.'la·sh;;.n ,in,deks J
`[ENGl
`Ion meter
`Instrument for measuring the de­
`modulation (modulation factor) of a modulated wave
`Jally expressed in percent.
`{,mlij·;;.'la·sh~n ,m&l-::Ir )
`ion rise
`Increase of the modulation per­
`[ELECTR]
`caused by nonlinearity of any tuned amplifier, usually
`I ,maj'::I'!ii:
`ntermediate-frequency stage of a receiver.
`:}
`ion spectrosc()py
`[SPECT] A branch of spectros­
`neemed with the measurement and interpretation of
`in transmission or reflection spectra induced (usually)
`nally applied perturbation, such as temperature or pres­
`I ,maj·;;.'lli·sh;;.n
`nge, or an electric or magnetic field.
`;'b'pe I
`[ENG ACOUS] An audio-frequency
`ion transformer
`nerwhich matc~es impedances and transmits audio fre­
`i between one or more plates of an audio output stage
`grid or plate of a[modulated amplifier. (, maj-~ 'Ia·sh;;.n
`!
`~m~r}
`[COMMUN] Phase mod­
`ion with a flxeq reference
`with a pilot carrier. {,maj·;;.'lii-sh::ln wi!!!, ;;. 'fixt 'ref,
`
`!1. The transmitter stage that supplies
`or
`[IlLIlCTR]
`lulating signal to the modulated amplifier stage or that
`the modulated a,mplifier stage to produce pulses at de­
`;ranlS as in radar.! 2_ A device that produces modulation
`neans, such as by virtue of a nonlinear characteristic or
`rolling some cit;cuit quantity in accordance with the
`rm of a modulatihg signal. 3. One of the electrodes of
`tor.
`('maj9,Ilid-::Ir}
`tor crystal
`[OPTICS] Crystal which is used to modu­
`~Iarized light beam by the use of the Pockel's effect;
`~ a modulator in laser systems.
`('maj'~,llid'::Ir ,krist·
`
`tor-demodulator See modem.
`I
`[ELECTR] Cold cathode recorder tube
`.Iorglow tube
`lied for facsimile and sound-on-film recording; provides
`
`('maj·;;.,Jad·~r de'maj'
`
`I 'maj'::I,lad'
`
`
`a modulated high-intensity point source of light.
`~r 'glo ,t(jb }
`
`module
`[AERO ENG] A self-contained unit which serves as a
`building block for the overall structure in space technology;
`usually designated by its primary function. such as command
`module or lunar landing module.
`[COMPUT SCI] 1_ A distinct
`and identifiable unit of computer program for such purposes as
`compiling, loading, and linkage editing. 2. One memory bank
`and associated electronics in a computer.
`[ELECTR] A pack­
`aged assembly of wired components, built in a standardized size
`and having standardized plug-in or solderable terminations.
`[ENG] A unit of size used as a basic component for standard­
`izing the design and construction of buildings, building parts,
`and furniture.
`[MATH] A vector space in which the scalars are
`I 'maj·(j] }
`a ring rather than a field.
`[MATH] 1. A group G modulo a subgroup H is the
`modulo
`quotient group GIH of cosets of H in G. 2. A technique of
`identifying elements in an algebraic structure in such a manner
`that the resulting collection of identified objects is the same type
`I 'maj'::I,lo }
`of structure.
`modulo N
`[MATH] Two integers are said to be congruent
`modulo N (where N is some integer) if they have the same
`remainder when divided by N. {'maj'::I,lii 'en I
`modulo N arithmetic
`[MATH] Calculations in which all in­
`tegers are replaced by their remainders after division by N
`(where N is some fixed integer.) {'maj'::I,lii ;en ::I'rith·m::l·tik I
`modulo N check
`[COMPUT SCI] A procedure for verification
`of the accuracy of a computation by repeating the steps in mod­
`ulo N arithmetic and comparing the result with the original result
`(modulo NJ. Also known as residue check. {'maj'::I,lo :en
`'chek I
`modulo-two adder [COMPUT scI] A logical circuit for adding
`one-digit binary numbers. {'maj';;',lii:tii 'ad'::Ir I
`[MATH] 1. The modulus of a logarithm with a given
`modulus
`base is the factor by which a logarithm with a second base must
`be multiplied to give the first logarithm. 2. See absolute value.
`I 'maj'::I'lds I
`modulus of a congruence
`[MATH] A number a, such that
`two specified numhers band c give the same remainder when
`divided by a; band c are then said to be congruent, modUlUS a
`I 'maj-::I-I::Is::lv::l k::ln'grU'::Ins I
`(or congruent, modulo a).
`modulus of compression See bulk modulus of elasticity.
`I 'maj'::I'I::Is;;,v k;;.m'presh-~n I
`modulus of continuity
`[MATH) For a real valued continuous
`function/. this is the function whose value at a real number r is
`fi,y) where the modulus
`the maximum of the modulus of fix) -
`of x
`y is less than 1'; this function is useful in approximation
`theory. {'maj·::I·I;;.s;;.v ,kiint·::In'(j·;;.d·e )
`modulus of decay
`[MECH] The time required for the ampli­
`tude of oscillation of an underdamped harmonic oscillator to
`drop to lie of its initial value; the reciprocal of the damping
`factor. {;maj'::I'I:;)s:;)v di 'ka I
`modulus of deformation
`[MECH] The modulus of elasticity
`of a material that deforms other than according to Hooke's law.
`I 'maj';;"l::ls;;,v ,de,for'ma'sh::ln I
`[ASTRON] The quantity m - M, where
`modulus of distance
`M is the absolute magnitUde of a given star and m is its apparent
`I 'maj';;"l::ls:;)v
`magnitude. Also known as distance modulus.
`'dis·tens I
`[MECH] The ratio of the increment of
`modulus of elastiCity
`some specified form of stress to the increment of some specified
`form of strain, such as Young's modulus, the bulk modulus, or
`the shear modulus. Also known as coefficient of elasticity;
`elasticity modulus; elastic modulus. {'maj·::I·I::Is dV i,las'tis'
`~d'e J
`[MECH] A measure of a ma­
`modulus of elasticity in shear
`terial's resistance to shearing stress, equal to the shearing stress
`divided by the resultant angle of deformation expressed in ra­
`dians. Also known as coefficient of rigidity; modulus of rigid­
`I 'maj·::I·I;;.s ~v i,las'tis'
`ity; rigidity modulus; shear modulus.
`::Id'e in 'shir I
`[MECH] The maximum mechanical
`modulus of resilience
`energy stored per unit volume of material when it is stressed to
`its elastic limit. {'maj'::I'I:;)s::lv ri'zil·y;;.ns }
`modulus of rigidity See modulus of elasticity in shear. {'maj·
`;;"I::Is ::IV ri'jid'~d'e J
`[MECHl The maximum
`modulus of rupture in bending
`stress per unit area that a specimen can withstand without break­
`ing when it is bent, as calculated from the breaking load under
`
`