- 行业: Printing & publishing
- Number of terms: 178089
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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.
The process of forming stable or permanent visible images directly or indirectly by the action of light or other forms of radiation on sensitive surfaces. Traditionally, photography utilizes the action of light to bring about changes in silver halide crystals. These changes may be invisible, necessitating a development step to reveal the image, or they may cause directly visible darkening (the print-out effect). Most photography is of the first kind, in which development converts exposed silver halide to (nonsensitive) metallic silver.
Industry:Science
The metallic element, Bi, of atomic number 83 and atomic weight 208.980 belonging in the periodic table to group 15. Bismuth is the most metallic element in this group in both physical and chemical properties. The only stable isotope is that of mass 209. It is estimated that the Earth's crust contains about 0.00002% bismuth. It occurs in nature as the free metal and in ores. The principal ore deposits are in South America. However, the primary source of bismuth in the United States is as a by-product in refining of copper and lead ores.
Industry:Science
The line that marks the separation of land and water along the margin of a pond, lake, sea, or ocean; also called the shoreline. The strand line is very dynamic. It changes with the tides, storms, and seasons, and as long-term sea-level changes take place. The sediments on the beach respond to these changes, as do the organisms that live in this dynamic environment. On a beach organisms move with the tides, and on a rocky coast they tend to be organized relative to the strand line because of special limitations or adaptations to exposure.
Industry:Science
The machine element that supports a roller and wheel so that they can perform their basic functions of rotation. Shafting, made from round metal bars of various lengths and machined to dimension the surface, is used in a great variety of shapes and applications. Because shafts carry loads and transmit power, they are subject to the stresses and strains of operating machine parts. Standardized procedures have been evolved for determining the material characteristics and size requirements for safe and economical construction and operation.
Industry:Science
The prevention of an enzymatic reaction due to interaction of an enzyme with a substance that decreases the rate of catalysis by the enzyme. The compound causing the effect is termed an inhibitor. Enzyme inhibitors are important regulators in the normal control of enzymatic reactions in living organisms, are useful in the study of enzyme mechanisms and cellular reactions, and are important chemotherapeutic agents. Inhibitors may have chemical structures that are similar to one of the substrates of the enzyme but may also be quite different.
Industry:Science
The process by which a disturbance at one point in space is propagated to another point more remote from the source with no net transport of the material of the medium itself. For example, sound is a form of wave motion; wind is not. Wave motion can occur only in a medium in which energy can be stored in both kinetic and potential form. In a mechanical medium, kinetic energy results from inertia and is stored in the velocity of the molecules, while potential energy results from elasticity and is stored in the displacement of the molecules.
Industry:Science
The science of optical systems in which a controllable optical element, usually a deformable mirror, is used to optimize the performance of the system, for example, to maintain a sharply focused image in the presence of wavefront aberrations. A distinction is made between active optics, in which optical components are modified or adjusted by external control to compensate slowly changing disturbances, and adaptive optics, which applies to closed-loop feedback systems employing sensors and data processors, operating at much higher frequencies.
Industry:Science
The technique of making measurements in drill holes with probes designed to measure the physical and chemical properties of rocks and their contained fluids. Over a million holes are drilled annually around the world to probe for oil, gas, solid minerals, and fresh water, and to better understand the subsurface geology. Much information can be obtained from samples of rock brought to the surface in cores or bit cuttings, or from other clues while drilling, such as penetration rate; but the greatest amount of information comes from well logs.
Industry:Science
The phenomenon of superconductivity, the complete loss of electrical resistivity in a material, holds tremendous potential for applications including magnetically levitated trains, highly efficient electrical cables and generators, environmentally friendly transformers, energy storage devices, and sophisticated electronic components. Many applications already use superconductors, including magnetic resonance imaging (MRI), sensitive magnetometers based on superconducting quantum interference device (SQUID) technology, and particle accelerators.
Industry:Science
The preferred operational-calculus tool for analysis and design of discrete-time systems. (It should not be confused with the <i>z</i> transformation.) The role of the <i>z</i> transform with regard to discrete-time system is similar to that of the Laplace transform for continuous systems. In fact, the Laplace transform is a specialized case of the <i>z</i> transform. The <i>z</i> transform is by far the more insightful tool, and the Laplace transform is just the limiting case of the <i>z</i> transform in a practical as well as a conceptual way.
Industry:Science
