- 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 time-varying part of a voltage that is ideally time-invariant. Most electronic systems require a direct-current voltage for at least part of their operation. An ideal direct-current voltage is available from a battery, but batteries are impractical for many applications. To obtain a direct-current voltage from the alternating-current power mains requires using some type of power supply.
Industry:Science
The lowest-cost means for transmitting power between shafts that are not necessarily parallel. Belts run smoothly and quietly, and they cushion motor and bearings against load fluctuations. Belts typically are not as strong or durable as gears or chains. However, improvements in belt construction and materials are making it possible to use belts where formerly only chains or gears would do.
Industry:Science
The mass of primary tissue in roots and stems extending inward from the epidermis to the phloem. The cortex may consist of one or a combination of three major tissues: parenchyma, collenchyma, and sclerenchyma. In roots the cortex almost always consists of parenchyma, and is bounded, more or less distinctly, by the hypodermis (exodermis) on the periphery and by the endodermis on the inside.
Industry:Science
The process of manufacturing software systems. A software system consists of executable computer code and the supporting documents needed to manufacture, use, and maintain the code. For example, a word processing system consists of an executable program (the word processor), user manuals, and the documents, such as requirements and designs, needed to produce the executable program and manuals.
Industry:Science
The process of separating hydrocarbons which solidify readily (waxes) from petroleum fractions. Removal of wax is usually necessary to produce lubricating oil which will remain fluid down to the lowest temperature of use. It is therefore an important step in the manufacture of lubricating oils. The wax removed may be purified further to produce commercial paraffin or microcrystalline waxes.
Industry:Science
The study of fossil plants of the geologic past. A paleobotanist is a plant historian who carefully pieces together the geologic history of the plant kingdom. Other organisms, including fungi and various types of microscopic plankton, are also studied by paleobotanists. Paleobotany is a branch of paleontology that requires a knowledge of both plant biology (botany) and the geological sciences.
Industry:Science
The notion that mass, or matter, can be neither created nor destroyed. According to conservation of mass, reactions and interactions which change the properties of substances leave unchanged their total mass; for instance, when charcoal burns, the mass of all of the products of combustion, such as ashes, soot, and gases, equals the original mass of charcoal and the oxygen with which it reacted.
Industry:Science
The occultation (obscuring) of one celestial body by another. Solar and lunar eclipses take place at syzygies of the Sun, Earth, and Moon, when the three bodies are in a line. At a solar eclipse, the Moon blocks the view of the Sun as seen from the Earth. At a lunar eclipse, the Earth's shadow falls on the Moon, darkening it, and can be seen from wherever on Earth the Moon is above the horizon.
Industry:Science
The taking of minerals from the earth, including production from surface waters and from wells. Usually the oil and gas industries are regarded as separate from the mining industry. The term mining industry commonly includes such functions as exploration, mineral separation, hydrometallurgy, electrolytic reduction, and smelting and refining, even though these are not actually mining operations.
Industry:Science
The technology and science of metallic materials. Metallurgy as a branch of engineering is concerned with the production of metals and alloys, their adaptation to use, and their performance in service. As a science, metallurgy is concerned with the chemical reactions involved in the processes by which metals are produced and the chemical, physical, and mechanical behavior of metallic materials.
Industry:Science
