- 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.
An assemblage to provide cover for homes, buildings, and commercial, industrial, and recreational areas. Roofs are constructed in different forms and shapes with various materials. A properly designed and constructed roof protects the structure beneath it from exterior weather conditions, provides structural support for superimposed loads, provides diaphragm strength to maintain the shape of the structure below, suppresses fire spread, and meets desired esthetic criteria. Roofs have been constructed in many shapes by using structural assemblies and materials including beams, arches, cut stone slabs, cast-iron segments, masonry or terra-cotta tiles, and thatched grasses.
Industry:Science
An assembly at the rear of an airplane, consisting of the tail cone, the horizontal tail, and one or more vertical tails.
Industry:Science
An assembly of equipment in an electric power system through which electrical energy is passed for transmission, distribution, interconnection, transformation, conversion, or switching.
Industry:Science
An assembly of two or more parts fastened together by inserting bolts through matching clearance holes in the parts and engaging nuts that are then tightened to clamp the assembly. The term bolted joint also colloquially denotes a screwed joint, for which screws are inserted through clearance holes in one part and tightened into internal threads in another part by turning the screw head.
Industry:Science
An associative, noncommutative algebra based on four linearly independent units or basal elements. Quaternions were originated in Dublin, Ireland, on October 16, 1843, by W. R. Hamilton (1805–1865), who is famous because of his canonical functions and equations of motion which are important in both classical and quantum dynamics.
Industry:Science
An astronomical object that appears starlike on a photographic plate but possesses many other characteristics, such as a large redshift, that prove that it is not a star. The name quasar is a contraction of the term quasistellar object (QSO), which was originally applied to these objects for their photographic appearance. The objects appear starlike because their angular diameters are less than about 1 second of arc, which is the resolution limit of ground-based optical telescopes imposed by atmospheric effects. Stars also have angular diameters much less than this, and so they too appear unresolved or pointlike on a photograph.
Industry:Science
An atmospheric disturbance involving perturbations of the prevailing pressure and wind fields on scales ranging from tornadoes (about 330 ft or 100 m across) to extratropical cyclones (1000–2000 mi or 2000–3000 km across); also, the associated weather (rain storm, blizzard, and the like). Storms influence human activity in such matters as agriculture, transportation, building construction, water impoundment and flood control, and the generation, transmission, and consumption of electric energy.
Industry:Science
An atom laser is a device that generates an intense coherent beam of atoms through a stimulated process. It does for atoms what an optical laser does for light. The atom laser emits coherent matter waves, whereas the optical laser emits coherent electromagnetic waves. Coherence means, for instance, that atom laser beams can interfere with each other.
Industry:Science
An atom which possesses one valence electron orbiting about an atomic nucleus within an electron shell well outside all the other electrons in the atom. Such an atom approximates the hydrogen atom in that a single electron is interacting with a positively charged core. Early observations of atomic electrons in such Rydberg quantum states involved studies of the Rydberg series in optical spectra. Electrons jumping between Rydberg states with adjacent principal quantum numbers, <i>n</i> and <i>n</i> − 1, with <i>n</i> near 80 produce microwave radiation. Microwave spectral lines due to such electronic transitions in Rydberg atoms have been observed both in laboratory experiments and in the emissions originating from certain low-density partially ionized portions of the universe called HII regions.
Industry:Science
An atomic or molecular system having an excess of negative charge. Negative ions, also called anions, are formed in attachment processes in which an additional electron is captured by an atom, molecule, or cluster. They can also be formed when a molecule or cluster dissociates. Doubly charged negative ions, also called dianions, have also been observed in the case of molecules and clusters. Here, two additional electrons have become attached to the neutral systems. Negative ions are destroyed in a controlled manner in detachment processes and, in the case of molecular ions or clusters, dissociation processes, when the ion interacts with photons, electrons, heavy particles, or external fields. Experimental studies of negative ions involve measurements of cross sections for detachment and dissociation.
Industry:Science
