- 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 removable metal lining, usually in the form of a bearing to carry a shaft. Generally a bushing is a small bearing in the form of a cylinder and is made of soft metal or graphite-filled sintered material. Bushings are also used as cylindrical liners for holes to preserve the dimensional requirements, such as in the guide bearings in jigs and fixtures for drilling holes in machine parts.
Industry:Science
A representation of an actual electric circuit or electronic device by a simple circuit whose behavior is very near to that of the actual circuit over a specified range of conditions. When these conditions are satisfied, the equivalent circuit may be said to constitute a macromodel of the actual circuit. The use of equivalent circuits is important in many of the analysis and design operations associated with electronic circuits. For example, a frequently used electronic device is the operational amplifier. One of the better-known operational amplifiers, the μA 741, is realized as an integrated circuit containing over 20 transistors. Many electric circuits, for example, active-<i>RC</i> (resistance-capacitance) filters, require the use of large numbers of operational amplifiers. In such applications, the use of equivalent circuits greatly simplifies analysis and design operations.
Industry:Science
A resistor that has the property of increasing in resistance as current flowing through it increases, and decreasing in resistance as current decreases. Therefore the ballast resistor tends to maintain a constant current flowing through it, despite variations in applied voltage or changes in the rest of the circuit. The ballast resistor acts as a variable load on the system; therefore it differs from load resistors, which have a constant resistance. Ballast resistors are now mainly of historical interest; electronic devices fulfilling the same function have replaced them.
Industry:Science
A response of a mechanical or electrical system in reaction to an external signal.
Industry:Science
A restriction on the natural degrees of freedom of a system. If <i>n</i> and <i>m</i> are the numbers of the natural and actual degrees of freedom, the difference <i>n</i> − <i>m</i> is the number of constraints. In principle <i>n</i> = 3<i>N</i>, where <i>N</i> is the number of particles, for example, atoms. In practice <i>n</i> is determined by the number of effectively rigid components.
Industry:Science
A reusable crewed orbital transportation system. The space shuttle, along with crewless (robotic) expendable launch vehicles such as Atlas and Delta, make up the United States Space Transportation System (STS). The shuttle provides the unique capability for in-flight rendezvous and retrieval of faulty or obsolescent satellites, followed by satellite repair, update, and return to orbit or return to Earth for repair and relaunch. The space shuttle also plays an essential continuing role in the construction and provisioning of the <i>International Space Station</i> (<i>ISS</i>) by transporting major components, such as the giant solar-cell arrays and the Canadian computer-driven double-ended robotic arm, from Earth to the <i>ISS</i> and installing them using extended extravehicular activity (EVA, or space walks) by trained <i>ISS</i> resident and shuttle-visiting astronauts.
Industry:Science
A reversible state during which the individual's voluntary functions are suspended but the involuntary functions, such as circulation and respiration, are uninterrupted; the sleeping subject assumes a characteristic posture with relative immobility and decreased responses to external stimuli.
Industry:Science
A ribonucleic acid (RNA) molecule that, like a protein, can catalyze specific biochemical reactions.
Industry:Science
A rickettsial disease, also known as cowdriosis, which is caused by the microorganism <i>Cowdria ruminantium</i> and is transmitted by ticks of the genus <i>Amblyomma</i>. The disease occurs in wild and domestic ruminants, primarily cattle, sheep, and goats, in sub-Saharan Africa and some Caribbean islands (for example, Guadeloupe, Antigua, and Marie-Galante); it is a major obstacle to improvement of livestock production in Africa.
Industry:Science
A rigid and wave-resistant marine structure that stands above its surroundings. Biologists and geologists specify that reefs are constructed by organisms that secrete calcium carbonate skeletons. To navigators, a reef is any rocky structure that poses a threat to navigation.
Industry:Science
