- 行业: Printing & publishing
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McGraw Hill Financial, Inc. is an American publicly traded corporation headquartered in Rockefeller Center in New York City. Its primary areas of business are financial, publishing, and business services.
A member of the plagioclase feldspar solid-solution series with a composition ranging from Ab<sub>30</sub>An<sub>70</sub> to Ab<sub>10</sub>An<sub>90</sub> (Ab = NaAlSi<sub>3</sub>O<sub>8</sub> and An = CaAl<sub>2</sub>Si<sub>2</sub>O<sub>8</sub>) (see <b>illus.</b>). In the high-temperature form, bytownite has the high-albite structure type in which Al and Si atoms are completely disordered; that is, neither element shows a preference for any of the four distinct tetrahedral sites. During cooling, natural material changes its Al/Si distribution, tending toward an ordered state in which Al and Si concentrate in different sites which alternate with one another in all directions. Bytownite is very abundant in basic igneous rocks, where it is the first plagioclase to crystallize under plutonic conditions; it forms the cores of zoned plagioclase phenocrysts in basaltic volcanics; and it sometimes occurs in anorthosites.
Industry:Science
A member of the plant family Leguminosae, and the name for the fruit produced by members of that family, as idealized in a bean or pea pod. The legume and grass families are by far the world's most important sources of food. Whereas grasses supply starch, legumes, which include beans, soybeans, peas, and alfalfa, supply protein and fats. Through their root nodules, which are inhabited by <i>Rhizobium</i> bacteria, the legumes also preserve the nitrogen balance in the soil.
Industry:Science
A member of the rho-theta family of air navigation systems which define an aircraft's position by its distance and bearing to a single beacon. Such systems inherently answer the navigator's questions of “in what direction” and “how far,” without additional computation, and are of particular value when the beacon has to be placed on a ship, oil-drilling rig, or small island. The main weakness of such systems is that bearing errors cause spatial error to increase with distance from the beacon. Major attention is therefore given to the reduction of bearing errors.
Industry:Science
A member of the viruses in the type species Parainfluenza 1, genus <i>Paramyxovirus</i>, family Paramyxoviridae; it is also called hemagglutinating virus of Japan (HVJ). Sendai virus was originally recovered in Sendai, Japan, from mice inoculated with autopsy specimens from newborns who died of fatal pneumonitis in an epidemic in 1952. Subsequent attempts to isolate this virus from humans were, however, mostly unsuccessful, although mice are commonly infected with Sendai virus along with rats, guinea pigs, hamsters, and pigs. It is believed that the natural host of Sendai virus is the mouse and that the virus is usually nonpathogenic for humans.
Industry:Science
A mercury-vapor lamp designed to produce ultraviolet radiation. Also, some fluorescent lamps and mercury-vapor lamps that produce light are used for ultraviolet effects.
Industry:Science
A metabolic bone disease in which the amount of bone tissue is reduced sufficiently to increase the likelihood of fracture. Fractures of the vertebrae, femur (hip), and wrist are the most common osteoporotic fractures, but other bones such as the ribs, upper arm, and pelvis may also fracture.
Industry:Science
A metal product containing two or more elements as a solid solution, as an intermetallic compound, or as a mixture of metallic phases. This article will describe alloys on the basis of their technical applications. Alloys may also be categorized and described on the basis of compositional groups.
Industry:Science
A metal-forming process whereby molten metal is poured into a cavity or mold and, when cooled, solidifies and takes on the characteristic shape of the mold. Casting offers several advantages over other methods of metal forming: it is adaptable to intricate shapes, to extremely large pieces, and to mass production; it can provide parts with uniform physical and mechanical properties throughout; and depending on the particular material being cast, the design of the part, and the quantity being produced, it can be more economical.
Industry:Science
A metallic chemical element, Gd, atomic number 64 and atomic weight 157.25, belonging to the rare-earth group. The naturally occurring element is composed of eight isotopes. It is named in honor of the Swedish scientist J. Gadolin. The oxide, Gd<sub>2</sub>O<sub>3</sub>, in powdered form is white, and solutions of the salt are colorless. Gadolinium metal is paramagnetic and becomes strongly ferromagnetic below room temperatures. The Curie point, where this transition occurs, is about 16 K.
Industry:Science
A metallic chemical element, Mg, in group 2 of the periodic system, atomic number 12, atomic weight 24.312. Magnesium is silvery white and extremely light in weight. The specific gravity is 1.74, and the density is 1740 kg/m<sup>3</sup> (0.063 lb/in.<sup>3</sup> or 108.6 lb/ft<sup>3</sup>). Because of this lightness combined with alloy strength suitable for many structural uses, magnesium has long been known as industry's lightest structural metal.
Industry:Science
