aperture


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aperture

 [ap´er-chur]
inferior aperture of minor pelvis (inferior aperture of pelvis) pelvic outlet.
numerical aperture an expression of the measure of efficiency of a microscope objective.
superior aperture of minor pelvis (superior aperture of pelvis) pelvic inlet.

ap·er·ture

(ap'er-chūr),
1. Opening. An inlet or entrance to a cavity or channel. In anatomy, a gap or hole.
See also: fossa, ostium, orifice, pore. Synonym(s): apertura [TA]
2. The diameter of the objective of a microscope.
Synonym(s): aditus [TA]
[L. apertura, an opening]

aperture

/ap·er·ture/ (ap´er-cher) opening.
piriform aperture  the anterior end of the bony nasal opening, connecting the external nose with the skull.

aperture

[ap′ərchər]
Etymology: L, apertura, an opening
an opening or hole in an object or anatomical structure.

ap·er·ture

(ap'ĕr-chŭr) [TA]
1. An inlet or entrance to a cavity or channel; in anatomy, an open gap or hole.
2. The diameter of the objective of a microscope.
Synonym(s): aditus [TA] , apertura [TA] .
[L. apertura, an opening]

aperture 

An opening, or the area of a lens, through which light can pass. See pupil.
angular aperture Half of the maximum plane subtended by a lens at the axial point of an object or image. (Sometimes the full plane angle is taken as the angular aperture but this is not convenient in optical calculations.) See sine condition.
aperture of a lenticular lens That portion of a lenticular lens which has the prescribed power (British Standard).
numerical aperture An expression designating the light-gathering power of microscope objectives. It is equal to the product of the index of refraction n of the object space and the sine of the angle u subtended by a radius of the entrance pupil at the axial point on the object, i.e. n sin u.
palpebral aperture The gap between the margins of the eyelids when the eye is open. An abnormal increase in the aperture occurs in some conditions, including Graves' disease, buphthalmos, Parinaud's syndrome and retrobulbar tumour. An abnormal decrease in the aperture occurs in some conditions, including ptosis, microphthalmos and ophthalmoplegia (Figs. A15 and A16). Syn. interpalpebral fissure (this term is more accurate although used infrequently); palpebral fissure. See exophthalmos.
aperture plane See aperture plane.
aperture ratio See relative aperture.
relative aperture The reciprocal of the f number. It is therefore equal to the ratio of the diameter of the entrance pupil to the primary focal length of an optical system. Syn. aperture ratio. Note: the definition of this term is not universally accepted; some authors define it as the reverse of the above. See antimongoloid slant; f number.
Fig. A15 Palpebral aperture PA and corneal apex CAenlarge picture
Fig. A15 Palpebral aperture PA and corneal apex CA
Fig. A16 Average dimensions of the normal palpebral aperture of a Caucasian eyeenlarge picture
Fig. A16 Average dimensions of the normal palpebral aperture of a Caucasian eye

ap·er·ture

(ap'ĕr-chŭr) [TA]
1. [TA] Opening. An inlet or entrance to a cavity or channel. In anatomy, a gap or hole.
Synonym(s): apertura.
2. The diameter of the objective of a microscope.
See also: fossa, ostium, orifice
Synonym(s): aditus [TA] .
[L. apertura, an opening]

aperture,

n an opening such as in bone.

aperture

an opening.

nasal aperture
the opening on the skull bounded by the nasal and incisive bones.
nasomaxillary aperture
the connecting aperture between the middle nasal meatus and the maxillary sinuses.
numerical aperture
measure of efficiency of a microscope objective proportional to the square root of the amount of light entering the instrument.
References in periodicals archive ?
JUST LIKE YOUR EYESWhat this camera does is vary the size of the aperture mechanically, giving it an aperture of f2.
With the Samsung Galaxy S9 and S9 Plus, the dual aperture implementation is set to be smarter than what Apple has done with the iPhone 7/8 Plus.
The variable aperture on the Galaxy S9 isn't entirely new.
Aperture said the acquisition of debt free direct will ensure continuity of service for clients of DFD.
preform aperture ANSI LF f140 in an amount of 4 units .
However, what this previous study didn't assess, and what our team set out to investigate this time, were gradual changes in aperture shape when moving from a square to a circle.
A A quick and easy way to get a smaller aperture for your rear sight is to first place a piece of plastic electrician's tape over the rear sight aperture.
A personal care article comprising a nonwoven fluid permeable topsheet having a body-facing surface and an opposing backside surface, a fluid impermeable backsheet and at least one intermediate layer disposed there between, wherein the fluid permeable topsheet comprises apertured holes wherein at least 10% of the aperture holes include a treatment rendering the aperture holes more hydrophilic than untreated portions of the fluid permeable topsheet, and wherein the fluid permeable topsheet other than the aperture holes comprises a surface composition selected from a hydrophobic composition, a superhydrophobic composition and combinations thereof.
The idea is to do away with bulky satellite communication dishes and replace them with low-profile distributed aperture terminals--several small antennas working together to act as a single large antenna.
We maintain that it possible to achieve better yields using a standard laser-cut stencil, but that rethinking and modifying (or "editing," as the major stencil houses like to say) the Gerber data for the stencil aperture cut can produce better results with fine-pitch.
The EyePal Peep Sighting System provides an aperture system for immediate sense of eye relief as the image of the target and all of the elements come clearly into focus.
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