| polarize | To communicate polarity to. Origin: Cf. F. Polarizer. Source: Websters Dictionary (01 Mar 1998) |
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| polarized light | <microscopy> Light that is vibrating in one plane (plane-polarized light), light with a rotary vibration (circular polarized light), or light that is vibrating elliptically (elliptically polarized light). Moonlight and skylight are polarized, as is much reflected light, cloud light is polarized under certain conditions. However, naturally polarized light is, on the whole, rather imperfectly polarized. (05 Aug 1998) |
| polarized light microscope | <instrument, microscopy> A microscopical polarizcope, i.e., a compound microscope which is equipped with two polars and a Bertrand lens, chemists and mineralogists are the principal users. (05 Aug 1998) |
| polarizer | <physics> That which polarizes; especially, the part of a polarizcope which receives and polarizes the light. It is usually a reflecting plate, or a plate of some crystal, as tourmaline, or a doubly refracting crystal. <microscopy> A first polarizing element inserted before a preparation. When its vibration direction is at right angles to the vibration direction of the analyser, the field becomes black if no anisotropic specimen is on the stage or when viewing an anisotropic substance in an extinction position or directly down an optic axis of an anisotropic crystal. See: analyser, eyepiece, positive. (28 Oct 1998) |
| polarizing element | <microscopy> A general term for a device for producing or analysing plane-polarized light. It may be a Nicol prism, some other form of calcite prism, a reflecting surface, or a polarizing filter. (05 Aug 1998) |
| polarizing power | <chemistry> Means that a charged species such as a proton can attract negatively charged electrons which causes a shift in the orbital. The higher the positive charge and the smaller the smaller the size, the greater the polarizing power of the species. (09 Jan 1998) |
| polarography | An electrochemical technique for identifying and estimating the concentration of reducible elements by means of the dual measurement of the current flowing through an electrochemical cell (which contains the test solution) and the electrical potential between the two electrodes as the potential is increased at a constant rate by an external voltage source. As the voltage reaches the standard electrode potential of the test substance, there is a sharp increase in current flow. The indicator electrode is usually a dropping mercury electrode. (12 Dec 1998) |
| polars | <microscopy> Two polarizing elements in a polarized light microscope. The polar placed between the light source and substage condenser is called the polarizer, the polar placed between the objective and ocular is called the analyser. The vibration directions of the two polars may be crossed 90 degrees, to achieve crossed polars, slightly uncrossing one polar gives slightly uncrossed polars, removing the analyser results in plane-polarized light. (05 Aug 1998) |
| polary | Tending to a pole; having a direction toward a pole. Source: Websters Dictionary (01 Mar 1998) |
| polatouche | <zoology> A flying squirrel (Sciuropterus volans) native of Northern Europe and Siberia. Synonym: minene. Origin: F. (01 Mar 1998) |
| poldine methylsulfate | 2-Benziloyloxymethyl-1,1-dimethylpyrrolidinium methylsulfate;an anticholinergic agent. (05 Mar 2000) |
| pole | 1. A long, slender piece of wood; a tall, slender piece of timber; the stem of a small tree whose branches have been removed; as, specifically: A carriage pole, a wooden bar extending from the front axle of a carriage between the wheel horses, by which the carriage is guided and held back. A flag pole, a pole on which a flag is supported. A Maypole. See Maypole. A barber's pole, a pole painted in stripes, used as a sign by barbers and hairdressers. A pole on which climbing beans, hops, or other vines, are trained. 2. A measuring stick; also, a measure of length equal to 5 yards, or a square measure equal to 30 square yards; a rod; a perch. <botany> Pole bean, a horizontal timber resting on the tiebeams of a roof and receiving the ends of the rafters. It differs from the plate in not resting on the wall. Origin: As. Pal, L. Palus, akin to pangere to make fast. Cf. Pale a stake, Pact. 1. Either extremity of an axis of a sphere; especially, one of the extremities of the earth's axis; as, the north pole. 2. <geometry> A point upon the surface of a sphere equally distant from every part of the circumference of a great circle; or the point in which a diameter of the sphere perpendicular to the plane of such circle meets the surface. Such a point is called the pole of that circle; as, the pole of the horizon; the pole of the ecliptic; the pole of a given meridian. 3. <physics> One of the opposite or contrasted parts or directions in which a polar force is manifested; a point of maximum intensity of a force which has two such points, or which has polarity; as, the poles of a magnet; the north pole of a needle. 4. The firmament; the sky. "Shoots against the dusky pole." (Milton) 5. <geometry> See Polarity, and Polar, Magnetic pole. See Magnetic. <geography> Poles of the earth, or Terrestrial poles, the two opposite points on the earth's surface through which its axis passes. Poles of the heavens, or Celestial poles, the two opposite points in the celestial sphere which coincide with the earth's axis produced, and about which the heavens appear to revolve. Origin: L. Polus, Gr. A pivot or hinge on which anything turns, an axis, a pole; akin to to move: cf. F. Pole. Source: Websters Dictionary (01 Mar 1998) |
| pole cell | <cell biology> A cell at or near the animal or vegetal pole of an embryo. (18 Nov 1997) |
| pole fibre | <cell biology> Microtubules inserted into the pole regions of the mitotic spindle (each pole is the product of the division of the centrioles and constitutes a microtubule organising centre. (18 Nov 1997) |
| pole ligation | A ligation at the root of an organ to shut off or diminish blood supply. (05 Mar 2000) |