- 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.
Any technique for the photographic recording of schlieren, which are regions or stria in a medium that is surrounded by a medium of different refractive index. Refractive index gradients in transparent media cause light rays to bend (refract) in the direction of increasing refractive index. This is a result of the reduced light velocity in a higher-refractive-index material. This phenomenon is exploited in viewing the schlieren, with schlieren photographs as the result. Modern schlieren systems are rarely limited to photography; electronic video recorders, scanning diode array cameras, and holography are widely used as supplements.
Industry:Science
Evidence of early boat and ship structures beyond the level of log canoes and rafts indicates that they shared comparatively simple shapes across cultures, time, and geography. From Egyptian (ca. 2400 B.C.), Roman, or East Asian (reported during the Dark Ages) times to present, there is a basic geometry of bottoms that are flat across and curved up fore and aft (that is, parallel to the midline of the boat) and sides vertical to flaring outwards 30° or more. These simple shapes typically did not reflect an absence of understanding of how to build more complex shapes, but allowed for more affordable ships that could be built quickly.
Industry:Science
Biosensors combine the recognition power of biological systems with advanced transducers and microelectronics to yield analytical instruments with unique measurement capabilities. The new generation of electrochemical blood-glucose monitors are widely used by diabetic people in their homes. While the measurement of glucose currently dominates commercial activity in the biosensor field, simple inexpensive instruments can be constructed to measure thousands of other analytes. These instruments have applications in medicine, the pharmaceutical industry, the environment, the food and process industries, as well as in security and defense.
Industry:Science
Grass of genus <i>Poa</i> (also called meadowgrass), of the family Graminae (Poaceae). About 50 species are natural to the United States, and 4 are of economic importance: Kentucky bluegrass (<i>P. pratensis</i>), used in lawns and pasture; Canada bluegrass (<i>P. compressa</i>), used for erosion control; roughstalk bluegrass (<i>P. trivialis</i>), adapted for turf in cool wet shade; and annual bluegrass (<i>P. annua</i>), a weed of cool moist sites. Kentucky bluegrass was introduced from Europe to Illinois by French missionaries, and spread rapidly throughout the Midwest, thriving where mean July temperatures are below 68°F (20°C).
Industry:Science
In astronomy, either an apparent east-to-west motion of a planet or comet with respect to the background stars or a real east-to-west orbital motion of a comet about the Sun or of a satellite about its primary. The majority of the objects in the solar system revolve from west to east about their primaries. However, near the time of closest approach of Earth and a superior planet, such as Jupiter, because of their relative motion, the superior planet appears to move from east to west with respect to the background stars. The same apparent motion occurs for an inferior planet, such as Venus, near the time of closest approach to Earth.
Industry:Science
Carbon dioxide (CO<sub>2</sub>) is a major greenhouse gas, and its level in the atmosphere has been increased by human activities. This increase should bring about global warming. Anthropogenically produced atmospheric carbon dioxide becomes involved in the global carbon cycle and may be stored in the oceans, soil, and living things. The fluxes between the atmosphere and various reservoirs are poorly known but must be understood in order to predict future rises in atmospheric carbon dioxide and global warming. There are also a number of other greenhouse gases whose effect on global warming is nearly comparable to that of carbon dioxide.
Industry:Science
Electric motors consume 64% of the electric power generated in the United State, with about half of this amount used by large motors (greater than 100 hp or 75 kW power). The efficiency of the average motor is 92%, and that of large motors about 96%. Conventional electric motors have reached their optimum in terms of power density and efficiency, and only the application of new materials can lead to further improvements. Superconductors offer the ability to carry very high direct electric current density without losses, and rotating apparatus (motors and generators) represent some of the most promising applications for superconductivity.
Industry:Science
Electric propulsion systems have the possibility of reducing the propellant mass needed for long-range planetary missions and drag compensation in orbiting satellites, as compared to chemical rocket systems. Electric propulsion reduces the mass needed for a given transfer of momentum to the space vehicle and thus its acceleration by exhausting the mass at a higher velocity. Electric propulsion systems are not used to launch payloads from the Earth's surface to low-Earth orbit because the force and energy required are too large. Instead, they are used in a space environment for drag compensation of space stations and for long space trips.
Industry:Science
Fundamental research on and development of smart structures and materials have shown great potential for enhancing the functionality, serviceability, and life-span of civil, aerospace, and mechanical infrastructure systems. This could contribute significantly to the improvement of productivity and quality of life. Moreover, the recent explosive growth in computer power and connectivity provides unprecedented opportunities for rapid and efficient access to enormous amounts of knowledge and data, including real-time data for monitoring and control of smart structures, and for studying vastly more complex systems than was hitherto possible.
Industry:Science
Any substance that causes the immune system to produce specific antibodies or T cells against it. An antigen may be a foreign substance from the environment (such as chemicals, bacterial or viral proteins, or pollen) or formed within the host's own body. Reactions of antigens with antibodies or T cells serve as a defense against microorganisms and other foreign bodies, but can be detrimental if the immune response is mounted against the “self,” as in autoimmune disorders. Antigen-antibody complexes are used in laboratory tests for detecting the presence of either antigen or antibody to determine a subject's previous exposure to pathogens.
Industry:Science
