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hardening

(Encyclopedia)hardening, in metallurgy, treatment of metals to increase their resistance to penetration. A metal is harder when it has small grains, which result when the metal is cooled rapidly. Sometimes small ar...

tuning systems

(Encyclopedia)tuning systems, methods for assigning pitches to the twelve Western pitch names that constitute the octave. The term usually refers to this procedure in the tuning of keyboard instruments. The need fo...

vapor pressure

(Encyclopedia)vapor pressure, pressure exerted by a vapor that is in equilibrium with its liquid. A liquid standing in a sealed beaker is actually a dynamic system: some molecules of the liquid are evaporating to f...

quadrant, in technology

(Encyclopedia)quadrant, in technology, angle-measuring device based on a scale of 90°. It is sometimes confused with the sextant, a similar instrument based on a scale of 60°. The quadrant is rarely used today. ...

superconductivity

(Encyclopedia)superconductivity, abnormally high electrical conductivity of certain substances. The phenomenon was discovered in 1911 by Heike Kamerlingh Onnes, who found that the resistance of mercury dropped sudd...

Saha, Meghnad

(Encyclopedia)Saha, Meghnad māgnädˈ säˈhä [key], 1893–1956, Indian physicist. He was a professor at Allahabad Univ. from 1923 to 1938 and a professor and physics department head at Calcutta Univ. from 1938....

liquid crystal

(Encyclopedia)liquid crystal, liquid whose component particles, atoms or molecules, tend to arrange themselves with a degree of order far exceeding that found in ordinary liquids and approaching that of solid cryst...

phase diagram

(Encyclopedia)CE5 Phase diagram for a substance, like water, which expands on freezing phase diagram, graph that shows the relation between the solid, liquid, and gaseous states of a substance (see states of ma...

boiling point

(Encyclopedia)boiling point, temperature at which a substance changes its state from liquid to gas. A stricter definition of boiling point is the temperature at which the liquid and vapor (gas) phases of a substanc...

liquefaction

(Encyclopedia)liquefaction, change of a substance from the solid or the gaseous state to the liquid state. Since the different states of matter correspond to different amounts of energy of the molecules making up t...