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 ?
Smartphone cameras have an aperture which is a tiny hole that allows light into the image sensor.
Dual aperture in a lens is one of the most used and implemented aspects of interchangeable lens cameras.
Ultimately, the square apertures produced better transfer efficiency rates, which improved dramatically with the use of an activated squeegee versus a standard squeegee.
When you get live TV on commercial airplanes, those are probably from distributed apertures," but the technological hurdles of building a distributed aperture terminal that receives and transmits signals from a moving vehicle on the ground are much greater, he said.
The EyePal is available in three versions; Rifle or Handgun Kits include two identically sized apertures matching their kit application and the Master Kit includes one rifle and one handgun aperture.
However, whatever the aperture field is (provided it is known a priori), rectangular apertures are well-described by a number of beams lower than the [N.
In such structures, the external electromagnetic fields can directly couple energy into the interior through apertures or slots.
Careful perusal of these comparisons revealed that the electric fields produced in the apertures and at interior points inside the hollow cylinder for both cases (the 10 m x 10 m ground plane vs the 8.
has released new coated optical apertures that measure 0.
Additionally, the relative focus shift curve crosses the line equal to one when linear arrays are by the larger apertures (Fig 4 b).
66 or greater has been the criterion for stencil apertures to achieve acceptable volume control in the printed solder paste "brick" for small apertures.