Page 55 - Electrical Engineering Dictionary

anti-plugging a feature to prevent a mo- lel, resultinginpermeabilitiesslightlygreater
tor from reversing direction directly across than unity; unlike paramagnetic substances,
the line. The purpose of the anti-plugging these materials exhibit hysteresis and have a
coil and contact is to prevent the motor from Curie temperature. Examples include man-
starting in the opposite direction until the ganese oxide, nickel oxide, and ferrous sul-
speed has slowed enough where the current fide.
and torque surges are within acceptable lev-
els when changing direction. antifuse a fuse-like device that when ac-
tivated becomes low-impedance.
anti-Stokes scattering the scattering of
light accompanied by a shift to higher fre- antiparticle a particle having the same
quencies. Contrast with Stokes Law of light mass as a given fundamental particle, but
scattering. whose other properties, while having the
same magnitude, may be of opposite sign.
antialiasing filter typically, a filter that Each particle has a partner called an antipar-
provides a prefiltering operation to ensure ticle. For example, electrical charge in the
that the frequency components of a signal case of the electron and positron, magnetic
above the Nyquist frequency are sufficiently moment in the case of the neutron and an-
attenuated so that, when aliased, they will tineutron. On collision a particle and its an-
cause a negligible distortion to the sampled tiparticle may mutually annihilate with the
signal. Seealsoaliasing, Nyquistfrequency. emission of radiation. Some properties of
the antiparticle will be identical in magni-
anticollision radar a type of radar, gen- tude but opposite in sign to the particle it is
erally operating in the millimeter wave fre- paired with.
quency range, used to prevent collision be-
tween moving vehicles. antipodal symmetry created by simulta-
neously mirroring an object in both the X and
anticomet tail (ACT) a special type of Y axes.
electron gun designed to handle highlights
by increasing beam current with a defocused antiproton antiparticle to the proton. It
beam during line retrace. is a strongly interacting baryon carrying unit
negative charge. It has mass of 938 MeV and
antidependency a potential conflict be- carries spin 1/2.
tween two instructions when the second in-
struction alters an operand which is read by antireflection coating See antireflective
the first instruction. For correct results, the coating.
first instruction must read the operand before
the second alters it. Also called a write-after- antireflective coating (ARC) a coating
read hazard. placed on top or below the layer of pho-
toresist to reduce the reflection of light, and
antidots regions of repulsive potential, hence reduce the detrimental effects of stand-
but which are configured so that particles ing waves or thin film interference.
(usuallyelectrons)canpassaroundthepoten-
tial and proceed past it. In the limiting case, AOA See angle of arrival.
a repulsive Coulomb potential is the simplest
antidot structure. AOTF See acousto-optic tunable filter.

antiferromagnetic materialsinwhichthe APART/PADE a computer code for anal-
internal magnetic moments line up antiparal- ysis of stray light in optical systems devel-

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