| Cassegrainian darkfield condenser | <microscopy> Named after Cassegrain, astronomer of the 17th century. A high-power, dark field con-denser to be used with objective apertures as high as 1.3. It is sometimes called the luminous spot ring condenser (Zeiss). (05 Aug 1998) |
|---|---|
| condenser, darkfield, bispheric | <microscopy> A dark field condenser consisting of a convex spherical reflector mounted concentric with a larger concave reflector. The rays are formed into a diverging cone by the convex reflector. The annular concave reflector then forms a hollow converging cone which is focused on the subject. See (05 Aug 1998) |
| condenser, darkfield, paraboloid | <microscopy> A dark field condenser consisting of a reflecting surface in the form of a segment of a paraboloid of revolution. Parallel rays entering the condenser around the periphery of the central stop are reflected from the curved surfaces and converge at the focus of the paraboloid. See (05 Aug 1998) |
| condenser or condenser lens | <physics> A term applied to lenses or mirrors designed to collect, control, and concentrate radiation in an illumination system. (05 Aug 1998) |
| Abbe's condenser | A system of two or three wide-angle, achromatic, convex and planoconvex lenses that may be moved upward or downward beneath the stage of a microscope, thereby regulating the concentration of light (directly from a bulb or reflected from a mirror) that passes through the material to be examined on the stage. (05 Mar 2000) |
| achromatic aplanatic condenser | <microscopy> A well-corrected microscope condenser lens, corrected for chromatic and spherical aberrations and satisfying the sine condition. (05 Aug 1998) |
| automatic condenser | A mechanically or electrically activated device used to provide condensing pressure in the placement of amalgam or gold foil in a cavity preparation. Synonym: automatic condenser. (05 Mar 2000) |
| cardioid condenser | A type of dark-field condenser. (05 Mar 2000) |
| cardioid dark field condenser | <microscopy> A condenser designed with two reflecting surfaces, the first, a spherical surface which reflects the rays to a second, cardioid (heart-shaped) surface. The virtue in such an arrangement is that, if the cardioid surface is of true figure, the lens is both achromatic and aplanatic. It has a limiting numerical aperture of about 1.0. Thus objectives of a greater numerical aperture cannot be used successfully with it. A true cardioid figure is the trace of a point on the circumference of a circle rolling around an equal, fixed circle. (05 Aug 1998) |
| paraboloid condenser | A type of dark-field condenser. (05 Mar 2000) |
| paraboloid dark field condenser | <microscopy> A lens of parabolic shape. The vertex end is ground back so that its focus can be brought into coincidence with the specimen on the slide. A central stop is provided to block the central rays. It is used chiefly for medium- power work. (05 Aug 1998) |
| condenser | <microscopy> In microscopy, the lens mounted before the microscope stage, which transmits light to the object. There are two main categories of condensers: (1) bright field and (2) dark field. Bright field condensers are of four distinct types: (a) Abbe condenser,, an uncorrected condenser composed of two separable lenses, (b) aplanatic condenser, (c) achromatic condenser which has full corrections for colour and spherical aberrations, (d) aplanatic achromatic condenser. The dark field condenser for low powers may be nothing more than a low-power bright field condenser with a central stop. Medium- or high-powered dark field condensers are usually of the cardioid or paraboloid type. The lamp lens is loosely called a condenser lens, but light-collecting lens is a more definite term. All microscope condensers must be carefully focused and aligned for best results. (05 Aug 1998) |
| condenser, Abbe | <microscopy> Originally a two-lens substage condenser combination designed by Ernst Abbe. It lacks chromatic correction though designed for a minimum of spherical aberration and has only a very low-angle aplanatic cone. It may be rated with a numerical aperture as high as 1.3. (05 Aug 1998) |
| condenser circle | <microscopy> The image of the aperture iris diaphragm of the substage condenser as seen in the back focal plane of the objective. (05 Aug 1998) |
| condenser, dark field | <microscopy> A condenser forming a hollow cone of light with its apex (or focal point) in the plane of the specimen. When used with an objective having a numerical aperture lower than the minimum numerical aperture of the hollow cone, only light deviated by the specimen enters the objective. Objects are seen as bright images against a dark background. The ordinary bright field condenser of low power, used with a central stop, makes a good dark field condenser. They all form a dark field while illuminating the specimen with a hollow cone of light. The lower limiting aperture of the condenser must be greater than the numerical aperture of the objective with which it is to be used. Thus, no direct light enters the objective, the specimen is seen by reflected or scattered light on a dark background. See: condensers See: special dark field condensers: paraboloid, cardioid and Cassegrainian. (05 Aug 1998) |
| darkfield condenser |
one with a central stop, permitting production of a hollow cone of light having its apex in the plane of the specimen.
출처: www.mercksource.com/pp/us/cns/cns_hl_dorlands.jspz...
|
|---|
제품명 |
판매사 |
보험코드 | 성분/함량 | 구분/보험급여 |
|---|
제품명 |
판매사 |
보험코드 | 성분/함량 | 구분/보험급여 |
|---|