- 行业: Printing & publishing
- Number of terms: 178089
- Number of blossaries: 0
- Company Profile:
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 type of mathematical equation used, typically, to represent curves in a plane or in space of three dimensions. In principle, however, there is no limitation to any particular number of dimensions. A parameter is actually an independent variable. In elementary analytic geometry a curve in the <i>xy</i> plane is often studied, in the first instance, as the locus of an equation <i>y</i> = <i>F</i>(<i>x</i>) or <i>G</i>(<i>x</i>,<i>y</i>) = 0. The form <i>y</i> = <i>F</i>(<i>x</i>) is not adequate for the complete representation of certain curves, whereas the form <i>G</i>(<i>x</i>,<i>y</i>) = 0 may be adequate. The circle <i>x</i><sup>2</sup> + <i>y</i><sup>2</sup> − 16 = 0 affords an example. But the form <i>G</i>(<i>x</i>,<i>y</i>) = 0 is not always convenient. The parametric form <i>x</i> = <i>f</i>(<i>t</i>), <i>y</i> = <i>g</i>(<i>t</i>) is often the most convenient; it is often the naturally occurring form of representation of the curve. For the circle <i>x</i><sup>2</sup> + <i>y</i><sup>2</sup> − 16 = 0, one possible parametric representation is <i>x</i> = 4 cos <i>t</i> and <i>y</i> = 4 sin <i>t</i>.
Industry:Science
A type of metamorphic rock formed during low-grade metamorphism of clay-rich sediments called pelites. Phyllites are very fine grained rocks with a grain size barely visible in a hand specimen. They have a well-developed planar element called cleavage defined by alignment of mica grains and interlayering of quartz-rich and mica-rich domains. Typically, mica grains show the greater alignment, although other mineral components (quartz, carbonate, and feldspars) may show a preferred shape orientation. Where all minerals of a particular type show the same degree of alignment and the fabric is well developed throughout the rock, the fabric is termed a penetrative fabric. Cleavage surfaces in phyllites have a glittery, lustrous sheen due to light reflecting off grains of chlorite and muscovite. The mineralogy of phyllites is dependent on chemical composition; typical minerals in phyllites are chlorite, muscovite, and quartz. Other minerals that may be present in phyllites formed during low-grade metamorphism include chlorotoid, garnet (rarely), sodium-mica, and sulfide minerals. These minerals are typically millimeter in scale and resolvable in a hand specimen by using a 10× hand lens.
Industry:Science
A type of pepper, <i>Capsicum annuum</i>, grown for its thick, sweet-fleshed red fruit. A member of the plant order Polemoniales, pimento is of American origin, and gets its name from the Spanish word designating all sweet peppers. In the United States, however, the term pimento generally refers to the heart-shaped varieties (cultivars) grown in the South for canning and used for stuffing olives and flavoring foods. Perfection is a popular variety. Harvesting begins when the fruits are fully red, usually 2½–3 months after planting. Georgia is the only important pimento-producing state.
Industry:Science
A type of pepper, <i>Capsicum annuum</i>, with nonpungent flesh, grown for its long red fruit. A member of the plant order Polemoniales and of American origin, it is most popular in Hungary and adjacent countries. Seeds are removed from the mature fruit, and the flesh is dried and ground to prepare the dry condiment commonly referred to as paprika. Production in the United States is limited, with California the only important producing state.
Industry:Science
A type of permanent-magnet alternating-current generator frequently used as a source of ignition energy on tractor, marine, industrial, and aviation engines. The higher cost of magneto ignition is not warranted in modern automobiles, where storage batteries are required for other electrically operated equipment. Hand-operated magneto generators were once widely used for signaling from local battery telephone sets.
Industry:Science
A type of pneumonia usually caused by infection with the bacterium <i>Legionella pneumophila</i>, but occasionally with a related species (such as <i>L. micdadei</i> or <i>L. dumoffii</i>). More than 40 species of <i>Legionella</i> are known, though not all have been associated with disease. The disease was first observed in an epidemic among those attending an American Legion convention in Philadelphia, Pennsylvania, in 1976. The initial symptoms are headache, fever, muscle aches, and a generalized feeling of discomfort. The fever rises rapidly, reaching 102–105<sup>°</sup>F (32–41<sup>°</sup>C), and is usually accompanied by cough, shortness of breath, and chest pains. Abdominal pain and diarrhea are often present. Diagnosis is often difficult, though there are several rapid diagnostic kits, including a urine antigen test that can augment chest x-ray presentation of a patchy interstitial infiltrate (atypical pneumonia in the case of Legionnaires' disease). Proper diagnosis is important since the mortality rate can be as high as 15% in untreated or improperly diagnosed cases. Erythromycin, new-generation fluroquinolones, and rifampicin are considered highly effective medications, whereas the penicillins and cephalosporins are ineffective.
Industry:Science
A type of symmetry law, an important example of which is flavor symmetry, an approximate internal symmetry law obeyed by the strong interactions of elementary particles. According to the successful theory of strong interactions, quantum chromodynamics, flavor symmetry is the consequence of the fact that the strong force (the so-called glue force, mediated by the SU<sup>color</sup><sub>3</sub> gauge field) is the same between any two quarks, the constituents of hadrons. It follows that if all the kinds (flavors) of quarks had the same mass, strong interactions would have the symmetry SU<sup>flavor</sup><sub><i>N</i></sub>, where <i>N</i> is the number of quark flavors. As a result, if nonstrong (electromagnetic and weak) interactions were neglected, then hadrons would occur as degenerate (all having the same mass) multiplets (irreducible representations) of the group SU<sub><i>N</i></sub>.
Industry:Science
A type of synchronous motor in which the rotor consists of a central nonmagnetic core upon which are mounted rings of magnetically hard material. The rings form a thin cylindrical shell of material with a high degree of magnetic hysteresis. The cylindrical stator structure is identical to that of conventional induction or synchronous motors and is fitted with a three-phase or a single-phase winding, with an auxiliary winding and series capacitor for single-phase operation.
Industry:Science
A type of wave propagated in the superfluid phase of liquid helium (helium II) and in certain other substances under special conditions. Predicted independently by L. Tisza in 1938 and L. Landau in 1941, such waves were observed first by V. Peshkov in 1944 and have subsequently provided a rich source of information for the study and understanding of the superfluid state. The name is misleading since second sound is not in any sense a sound wave, but a temperature or entropy wave. In ordinary or first sound, pressure and density variations propagate with very small accompanying variations in temperature; in second sound, temperature variations propagate with no appreciable variation in density or pressure.
Industry:Science
A ubiquitous network is one that provides services anywhere to anyone or anything on any device. Ubiquitous networks characteristically are mobile, wireless, and highly distributed. In transportation, a ubiquitous network would link drivers, vehicles, and infrastructure (such as traffic signals (lights), automatic toll collection, traffic advisory services, and media communication) by a network consisting of a very large number of wireless sensor nodes.
Industry:Science
