- 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.
The technique of storing information as a magnetic pattern on a moving magnetic medium. The medium may be a disk, either flexible (floppy) or rigid, or a tape. There are various techniques for “writing” the patterns, including the use of the magnetic field generated by an electric current in a miniature coil, or the use of a laser beam to heat the material. There are several techniques for “reading” the pattern, such as measuring the voltage induced in the same or different coil by the magnetic fields associated with the pattern, measuring the change in the resistance of a metal stripe due to this field, or measuring the polarization of a laser beam upon reflection from the medium.
Industry:Science
The study of physical and human landscapes, the processes that affect them, how and why they change over time, and how and why they vary spatially. Geographers determine the factors that influence landscapes or landscape features and seek to explain the interactions among them. This often involves explaining landscapes or environments from a spatial perspective by analyzing patterns or the lack of patterns. Geographers are also interested in the spatial arrangements of natural and human phenomena, as well as the relationships among these phenomena. Consequently, a key element of geography is areal differentiation, the process of defining regions with common unifying characteristics.
Industry:Science
The process by which groups of living organisms expand the space or range within which they live. Dispersal operates when individual organisms leave the space that they have occupied previously, or in which they were born, and settle in new areas. Natal dispersal is the first movement of an organism from its birth site to the site in which it first attempts to breed. Adult dispersal is a subsequent movement when an adult organism changes its location in space. As individuals move across space and settle into new locations, the population to which they belong expands or contracts its overall distribution. Thus, dispersal is the process by which populations change the area they occupy.
Industry:Science
The supporting structure for systems capable of leaving the Earth and its atmosphere, performing a useful mission in space, sometimes returning to the Earth and sometimes landing on other bodies. Among the principal technologies that enter into the design of spacecraft structures are aerodynamics, aerothermodynamics, heat transfer, structural mechanics, structural dynamics, materials technology, and systems analysis. In applying these technologies to the structural design of a spacecraft, trade studies are made to arrive at a design which fulfills system requirements at a minimum weight with acceptable reliability and which is capable of being realized in a reasonable period of time.
Industry:Science
The riddle of why is the sky is dark at night. This celebrated riddle originated in the sixteenth century. In 1823, Wilhelm Olbers presented it in the simplest terms: In an infinite universe, populated everywhere with stars, a line of sight in any direction when extended out into space must ultimately intercept the surface of a star. Hence stars should cover the entire sky. And if all stars are sunlike, the sky at every point should blaze as brightly as the disk of the Sun. Olbers has been credited incorrectly with the discovery of the riddle; he did, however, express it in this lucid form, and showed that the riddle still holds even when stars are irregularly distributed in clusters.
Industry:Science
The selection of the most favorable route for a ship's transit in the open ocean. Safety, economics, and environmental protection play a key role in determining this selection. In the late 1890s, the practice of following predetermined routes for shipping was adopted by shipping companies operating in the North Atlantic. As ships grew both in size and number, the ability to plan open-ocean transits based upon the environmental conditions expected during a voyage and the effect of these conditions upon the ship's performance became important factors in planning a ship's route. Ship routing is also referred to as weather routing, optimum track ship routing, and meteorological navigation.
Industry:Science
The scientific study of climate. Climate is the expected mean and variability of the weather conditions for a particular location, season, and time of day. The climate is often described in terms of the mean values of meteorological variables such as temperature, precipitation, wind, humidity, and cloud cover. A complete description also includes the variability of these quantities, and their extreme values. The climate of a region often has regular seasonal and diurnal variations, with the climate for January being very different from that for July at most locations. Climate also exhibits significant year-to-year variability and longer-term changes on both a regional and global basis.
Industry:Science
The study of rocks, their occurrence, composition, and origin. Petrography is concerned primarily with the detailed description and classification of rocks, whereas petrology deals primarily with rock formation, or petrogenesis. Experimental petrology reproduces in the laboratory the conditions of high pressure and temperature which existed at various depths in the Earth where minerals and rocks were formed. A petrological description includes definition of the unit in which the rock occurs, its attitude and structure, its mineralogy and chemical composition, and conclusions regarding its origin. For a discussion of mineral identification, petrographic analysis, and the classification of rocks
Industry:Science
The science of sound, which in its most general form endeavors to describe and interpret the phenomena associated with motional disturbances from equilibrium of elastic media. An elastic medium is one such that if any part of it is displaced from its original position with respect to the rest, as for example by an impact, it will return to its original state when the disturbing influence is removed. Acoustics was originally limited to the human experience produced by the stimulation of the human ear by sound incident from the surrounding air. Modern acoustics, however, deals with all sorts of sounds which have no relation to the human ear, for example, seismological disturbances and ultrasonics.
Industry:Science
The science that describes the structure, interactions, and reactions of organic compounds of biological significance at the molecular level. It represents the meeting of biochemistry, as attempts are made to describe the structure and physiology of organisms on an ever smaller scale, with organic chemistry, as attempts are made to synthesize and understand the behavior of molecules of ever-increasing size and complexity. Areas of research include enzymatic catalysis, the structure and folding of proteins, the structure and function of biological membranes, the chemistry of poly(ribonucleic acids) and poly(deoxyribonucleic acids), biosynthetic pathways, immunology, and mechanisms of drug action.
Industry:Science
