- 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.
A term used to refer to the free acid, H<sub>2</sub>NCN, or commonly to the calcium salt of this acid, CaCN<sub>2</sub>, which is properly called calcium cyanamide. Calcium cyanamide is manufactured by the cyanamide process, in which nitrogen gas is passed through finely divided calcium carbide at a temperature of 1000°C (1830°F).
Industry:Science
A term used variously to describe either a waxlike substance or a group of compounds. The former use pertains to the high-boiling residue obtained from certain petroleum crudes. It is recovered by freezing out on a cold drum and is purified by crystallization from methyl ethyl ketone. Paraffin wax is a mixture of 26- to 30-carbon alkane hydrocarbons; it melts at 52–57°C (126–135°F). Microcrystalline wax contains compounds of higher molecular weight and has a melting point as high as 90°C (194°F). The name paraffin is also used to designate a group of hydrocarbons—open-chain compounds of carbon and hydrogen with only single bonds, of the formula C<sub>n</sub>H<sub>2<i>n</i> + 2,</sub> where <i>n</i> is any integer. This usage is obsolete.
Industry:Science
A term usually applied to an instrument that generates voltage waves using digital technology. These digital instruments have largely supplanted the analog instruments that traditionally served in this role. Digital instruments have a number of important advantages over analog ones: they are more flexible and can be used to generate waveforms that are beyond the capabilities of analog instruments, they produce more accurate replicas of the desired mathematical waveforms, and their output is more stable and predictable over time.
Industry:Science
A test to measure a specific reaction between antigen and antibody which results in a visible precipitate.
Industry:Science
A tethered flying device that supports itself and the cable that connects it to the ground by means of the aerodynamic forces created by the relative motion of the wind. This relative wind may arise merely from the natural motions of the air or may be caused by towing the kite through the agency of its connecting cable.
Industry:Science
A textile fiber made of the undercoat of various animals, especially sheep; it may also be obtained from angora, goat, camel, alpaca, llama, and vicuna. Wool provides warmth and physical comfort that cotton and linen fabrics cannot give.
Industry:Science
A theorem from electric circuit theory. It is also known as the Helmholtz or Helmholtz-Thévenin theorem, since H. Helmholtz stated it in an earlier form prior to M. L. Thévenin. Closely related is the Norton theorem, which will also be discussed. Laplace transform notation will be used.
Industry:Science
A theorem in classical mechanics which relates the kinetic energy of a system to the virial of Clausius, as defined below. The theorem can be generalized to quantum mechanics and has widespread application. It connects the average kinetic and potential energies for systems in which the potential is a power of the radius. Since the theorem involves integral quantities such as the total kinetic energy, rather than the kinetic energies of the individual particles that may be involved, it gives valuable information on the behavior of complex systems. For example, in statistical mechanics it is intimately connected to the equipartition theorem; in astrophysics it may be used to connect the internal temperature, mass, and radius of a star and to discuss stellar stability. The virial theorem makes possible a very easy derivation of the somewhat counterintuitive result that as a star radiates energy and contracts it heats up, rather than cooling down.
Industry:Science
A theorem in fluid dynamics that pertains to the kinetic energy of an ideal fluid (that is, inviscid, incompressible, and irrotational) and provides uniqueness statements concerning the solution of potential-flow problems.
Industry:Science
A theorem in fluid mechanics which states that no forces act on a body moving at constant velocity in a straight line through a large mass of incompressible, inviscid fluid which was initially at rest (or in uniform motion). This seemingly paradoxical theorem can be understood by first realizing that inviscid fluids do not exist. If such fluids did exist, there would be no internal physical mechanism for dissipating energy into heat; hence there could be no force acting on the body, because work would then be done on the fluid with no net increase of energy in the fluid.
Industry:Science
