| ACS | acrocallosal syndrome; acrocephalosyndactyly; acute chest syndrome; acute confusional state; Alcon C... |
|---|---|
| APC | acetylsalicylic acid, phenacetin, and caffeine; activated protein C; adenoidal-pharyngeal-conjunctiv... |
| NA | Avogadro constant or number; nalidixic acid; Narcotics Anonymous; network administrator; neuraminida... |
| TACT | Tuned Aperture Computed Tomography |
|---|---|
| N.A. | numerical aperture |
| cloacal | Pertaining to the cloaca. (05 Mar 2000) |
|---|---|
| cloacal exstrophy | Congenital anomaly with two exstrophied bladder units separated by an exstrophied segment of intestine, which is usually caecum, receiving ileum superiorly and continuing distally to blend microcolon. A number of variants of anatomic disarray can occur. (05 Mar 2000) |
| cloacal membrane | A transitory membrane in the caudal area of the ventral wall of the embryo, separating the endodermal from the ectodermal cloaca; it is divided into anal and genitourinary membrane's that break down during the eighth to ninth week to establish the external opening for the alimentary and genitourinary tracts. (05 Mar 2000) |
| cloacal plate | A plate, composed of a layer of cloacal endoderm in contact with a layer of proctodeal ectoderm, which subsequently ruptures, forming the anal and urogenital openings of the embryo. (05 Mar 2000) |
| cloacal theory | The belief sometimes held by neurotic adults or children that a child is born, as a stool is passed, from a common opening. (05 Mar 2000) |
| angle of aperture | <ophthalmology, optics> The angle formed by lines drawn from the ends of the diameter of a lens to its point of focus. See: angular aperture. (05 Mar 2000) |
| angular aperture | The angle, in air, of light that passes from the object to the ends of the diameter of the front lens of the microscope objective. (05 Mar 2000) |
| anterior nasal aperture | The anterior nasal opening in the skull. Synonym: apertura piriformis, piriform opening. (05 Mar 2000) |
| aperture | <physics> The opening in an optical system which restricts the size of the bundle of rays incident on a given surface. (Usually circular and specified by diameter.) (09 Oct 1997) |
| aperture, angular | <microscopy> The angle between the most divergent rays that can pass through a lens to form the image of an object. The angle subtended between the axis of a lens and the largest accepted angle of the image-forming rays. With microscope objectives the trigonometric sine of this angle is used to define numerical aperture but as measured from the axial object point. (05 Aug 1998) |
| aperture correction | <microscopy> An electronic process used in some high-resolution video cameras and monitors that compensates for the loss in sharpness of detail due to the finite dimensions (aperture) of the scanning beam. (05 Aug 1998) |
| aperture diaphragm | A metal device that limits the area of the beam emerging from an X-ray tube. (05 Mar 2000) |
| aperture, effective | <microscopy> The diameter of the entrance pupil: it is the apparent diameter of the limiting aperture measured from the front. (05 Aug 1998) |
| aperture for electron microscopy | <technique> Anode aperture: The opening in the accelerating voltage anode shield of the electron gun through which the electrons must pass to irradiate the specimen. Condenser aperture: An opening in the condenser lens controlling the number of electrons entering the lens and the angular aperture of the electron beam. The angular aperture can also be controlled by the condenser lens current. Physical objective aperture: A metallic diaphragm, with a small central hole, used to limit the cone of electrons accepted by the objective lens. This improves image-contrast since highly scattered electrons are prevented from arriving at the Gaussian image plane and therefore cannot contribute to background fog. Aplanatic. Free from spherical aberration and coma. (05 Aug 1998) |
| aperture function | <microscopy> In a diffraction-limited optical system, the function that determines the relationship between the image and each point in the object. Modifying the aperture function changes the image according to the modified Fourier-filtering (or optical filtration) property of the aperture. (05 Aug 1998) |
| cloacal aperture |
the posterior opening on the body surface of the cloaca in vertebrates such as birds, reptiles, fish, and amphibians. Called also vent.
Ãâó: www.mercksource.com/pp/us/cns/cns_hl_dorlands.jspz...
|
|---|
Á¦Ç°¸í |
ÆÇ¸Å»ç |
º¸ÇèÄÚµå | ¼ººÐ/ÇÔ·® | ±¸ºÐ/º¸Çè±Þ¿© |
|---|
Á¦Ç°¸í |
ÆÇ¸Å»ç |
º¸ÇèÄÚµå | ¼ººÐ/ÇÔ·® | ±¸ºÐ/º¸Çè±Þ¿© |
|---|