- 行业: Printing & publishing
- Number of terms: 178089
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- 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 special branch of the paleobotanical sciences concerned with the origin, composition, mode of occurrence, and significance of the fossil plant materials that occur in, or are associated with, coal seams. Information developed in this field of science provides knowledge useful to the biologist in efforts to describe the development of the plant world, aids the geologist in unraveling the complexities of coal measure stratigraphy in order to reconstruct the geography of past ages and to describe ancient climates, and has practical application in the coal, coke, and coal chemical industries.
Industry:Science
A special case of a two-phase (gas and liquid) flow in which the liquid phase is the dispersed phase and exists in the form of many droplets. The gas phase is the continuous phase, so abstract continuous lines (or surfaces) can be constructed through the gas at any instant without intersection of the droplets. The droplets and the gas have velocities that can be different, so both phases can move through some fixed volume or chamber and the droplets can move relative to the surrounding gas.
Industry:Science
A special case of orthogonal functions that arise in many physical problems (often as the solutions of differential equations), in the study of distribution functions, and in certain other situations where one approximates fairly general functions by polynomials.
Industry:Science
A special form of mercury arc discharge lamp designed to produce ultraviolet radiation. These lamps also produce some radiant energy in the visible region of the spectrum, thus having a light output as well as an ultraviolet output. The lamps are principally used for tanning. The less common uses include therapeutically producing vitamin D in the body to treat rickets and causing fluorescence or photochemical reactions.
Industry:Science
A special operation in mathematics in which a set of points in one coordinate system is mapped or transformed into a corresponding set in another coordinate system, preserving the angle of intersection between pairs of curves.
Industry:Science
A special technique for obtaining an approximation to the solutions of the one-dimensional time-independent Schrödinger equation, valid when the wavelength of the solution varies slowly with position; also known as the WKB method. It is named after G. Wentzel, H. A. Kramers, and L. Brillouin, who independently in 1962 contributed to its understanding in the quantum-mechanical application. It was however, studied earlier by J. Liouville (1837), Lord Rayleigh (1912), and H. Jeffreys (1923). It is also called the BWK method, and the JWKB method, the classical approximation, the quasiclassical approximation, and the phase integral method.
Industry:Science
A special type of incandescent lamp that is designed to produce energy in the infrared portion of the electromagnetic spectrum. The lamps produce radiant thermal energy which can be used to heat objects that intercept the radiation. All incandescent lamps have radiation in three regions of the electromagnetic spectrum, the infrared, the visible, and the ultraviolet.
An infrared lamp with a filament operating at 2500 K will release about 85% of its energy in the form of thermal radiant energy, about 15% as visible light, and a tiny fraction of a percent as ultraviolet energy. The amount of infrared radiation produced by a lamp is a function of the input wattage of the lamp and the temperature of its tungsten filament. For most infrared lamps, the thermal radiation will be about 65–70% of the input wattage. A typical 250-W infrared lamp radiates about 175 W of thermal energy.
Industry:Science
A special type of nonlinear control system which can alter its parameters to adapt to a changing environment. The changes in environment can represent variations in process dynamics or changes in the characteristics of the disturbances.
Industry:Science
A specialized astronomical telescope substantially free from instrumentally scattered light, used to observe the solar corona, the faint atmosphere surrounding the Sun. Coronagraphs can record the emission component of the corona (spectral lines emitted by high-temperature ions surrounding the Sun) and the white-light component (solar photospheric light scattered by free electrons surrounding the Sun) routinely from high mountain sites under clear sky conditions. The emission and white-light components are typically only a few millionths the brightness of the Sun itself. Hence, the corona is difficult to observe unless the direct solar light is completely rejected, and unless instrumentally diffracted and scattered light that reaches the final image plane of the coronagraph is small relative to the coronal light.
Industry:Science
A specialized branch of civil engineering concerned with the planning, execution, and control of construction operations for such projects as highways, buildings, dams, airports, and utility lines.
Industry:Science
