- 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.
Disturbance to the normal or expected operation of electrical or electronic devices, equipment, and systems. Electrical interference is sometimes called radio-frequency interference (RFI) or electromagnetic interference (EMI). Such disturbances may range from nuisances (for example, an electric shaver jamming a nearby broadcast radio receiver) to catastrophes (for example, midair aircraft collision due to EMI navigation errors in holding patterns during bad weather in terminal areas). Electrical noise is a broader term that includes those phenomena that are generally termed electrical interference, but also includes naturally occurring currents or voltages that are more or less continuous and cannot be completely eliminated.
Industry:Science
Collectively, the various biological sciences concerned with the study of organisms and their components when exposed to the environment of space (or of a spacecraft beyond the immediate influence of Earth and its atmosphere). Space biology studies include all the biological science disciplines, such as molecular, cellular, developmental, environmental, behavioral, and radiation biology; physiology; medicine; biophysics; and biochemistry. Space biology encompasses both basic and applied sciences, and focuses on using space research to understand and resolve biological problems on Earth, as well as alleviating or preventing the deleterious physiological changes associated with space flight or habitation in non-Earth environments.
Industry:Science
High-pressure physics is concerned with the effects of high pressure on the properties of matter. Since most properties of matter are modified by pressure, the field of high-pressure physics encompasses virtually all branches of physics. The justification for classifying high-pressure physics as a separate field is that rather specialized and often ingenious techniques are needed, both to produce high pressures and to make measurements of changes of physical properties of a material at high pressure. This field is therefore analogous to the fields of low- and high-temperature physics. Indeed, high-pressure experiments have been performed at temperatures approaching absolute zero and at temperatures as high as 9000°F (5000°C).
Industry:Science
Epitaxial interfaces in solids are a special class of crystalline interfaces where the molecular arrangement of one crystal on top of another is defined by the crystallographic and chemical features of the underlying crystal. Royer (1928) systematically showed how the geometry of the atomic arrangement on a substrate could affect the crystallographic orientation of the overgrowth. The term “epitaxy” was introduced to describe the importance of having parallelism between two lattice planes with similar networks of closely similar spacing. Epitaxial phenomena are important to study and understand, as they occur widely in nature (such as oxidation) and are the foundation by which modern semiconductor devices are grown and fabricated.
Industry:Science
As recently as 2004, the Global Positioning System (GPS) receiver most widely used by the U.S. military was the PLGR (Precision Lightweight GPS Receiver). It is a five-channel receiver that operates on only one of the three GPS frequencies (L1), has a typical start-up time of over a minute, and costs about $2000. The PLGR receives encrypted military signals, is waterproof, and weighs about 1.4 kg (3 lb), making it far more rugged than any modern mobile telephone. But many of those mobile phones today have 12-channel A-GPS (Assisted GPS), which can compute a position within a second and acquire satellite signals that are more than 100 times weaker than can be acquired by the PLGR, and which adds less than $5 to the cost of the phone.
Industry:Science
Conserving the biodiversity of a region requires mapping where different species can be found and then identifying conservation sites that are large enough and arranged in such a way that long-term persistence of the targeted species is maximized. Increasingly, such planning entails looking beyond political boundaries to include regions whose boundaries are defined ecologically, such as a mountain range and the adjoining coastal plain. Mathematical models and other quantitative approaches are key elements in the toolkits of modern conservation planners and managers, both in investigating the extinction risks faced by different species and in identifying suites of sites that can protect as much of a region's biodiversity as possible.
Industry:Science
Earth's lower mantle contains vast amounts of rock, extending from just beneath the 660-km seismic discontinuity, all the way to the core-mantle boundary at 2900 km depth. Lower-mantle materials are essentially semiconductors, insulating enough to promote convective heat transfer from the core, but heat conduction is gaining recognition as an important control on geodynamic processes of the mantle at high pressure and temperature conditions. The optical properties of minerals, determined by light absorption experiments, provide information on the radiative component thermal conductivity (κ<sub>rad</sub>). The radiative component heat transfer is generally dependent on temperature, pressure, and the electronic structure of iron doping.
Industry:Science
Chemistry at very high pressures, arbitrarily chosen to be above 10,000 bars (10<sup>9</sup> pascals), and mainly concerned with solid and liquid states. A bar is 10<sup>6</sup> dynes/cm<sup>2</sup>, or 1.0197 kg/cm<sup>2</sup>, or 0.9869 atm, or 10<sup>5</sup> Pa. Multiples of the bar are the kilobar (1 kilobar = 10<sup>3</sup> bars = 10<sup>8</sup> Pa) and the megabar (1 mega-bar = 10<sup>6</sup> bars = 10<sup>11</sup> Pa). At 25°C (77°F) and 10 kilobars (10<sup>9</sup> Pa), nearly all ordinary gases are liquid or solid, and only a few liquids are not frozen; thus most high-pressure chemistry involves either higher temperatures, at which chemical reactions can occur at appreciable rates, or studies of internal arrangements in solids.
Industry:Science
Cells or organizations of cells which produce a variety of secretions. The process of secretion is a separation of a substance from the protoplast of a cell. The secreted substance may remain deposited within the secretory cell itself or may be released from the cell. Substances may be secreted to the surface of the plant or into intercellular cavities or canals. Some of the many substances contained in the secretions are not further utilized by the plant (resins, rubber, tannins, and various crystals), while others take part in the functions of the plant (enzymes and hormones). Secretory structures range from single cells scattered among other kinds of cells to complex structures involving many cells; the latter are often called glands.
Industry:Science
In a business or industrial context, the ratio of output production to input effort. The productivity ratio is an indicator of the efficiency with which an enterprise converts its resources (inputs) into finished goods or services (outputs). If the goal is to increase productivity, this can be done by producing more output with the same level of input. Productivity can also be increased by producing the same output with fewer inputs. One problem with trying to measure productivity is that a decision must be made in terms of identifying the inputs and outputs and how they will be measured. This is relatively easy when productivity of an individual is considered, but it becomes difficult when productivity involves a whole company or a nation.
Industry:Science
