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In thermodynamics, a critical point (or critical state) is the end point of a phase equilibrium curve. One example is the liquid–vapor critical point, the end point of the pressure–temperature curve that designates conditions under which a liquid and its vapor can coexist.
Other liquid crystal materials change color when stretched or stressed. Thus, liquid crystal sheets are often used in industry to look for hot spots, map heat flow, measure stress distribution patterns, and so on. Liquid crystal in fluid form is used to detect electrically generated hot spots for failure analysis in the semiconductor industry. [85]
Attributes of the resulting crystal depend largely on factors such as temperature, air pressure, cooling rate, and in the case of liquid crystals, time of fluid evaporation. Crystallization occurs in two major steps. The first is nucleation, the appearance of a crystalline phase from either a supercooled liquid or a supersaturated solvent.
Ethane (US: / ˈ ɛ θ eɪ n / ETH-ayn, UK: / ˈ iː θ eɪ n / EE-thayn) is a naturally occurring organic chemical compound with chemical formula C 2 H 6. At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petrochemical by ...
crystal I → liquid 14.703 kJ/mol at −89.0 °C Std entropy change of vaporization, Δ vap S o crystal I → liquid 79.87 J/(mol·K) at −89.0 °C Std enthalpy change of state transition, Δ trs H o crystal II → crystal I 2.282 kJ/mol at −183.3 °C Std entropy change of state transition, Δ trs S o crystal II → crystal I 25.48 kJ/mol ...
Crystallography ranges from the fundamentals of crystal structure to the mathematics of crystal geometry, including those that are not periodic or quasicrystals. At the atomic scale it can involve the use of X-ray diffraction to produce experimental data that the tools of X-ray crystallography can convert into detailed positions of atoms, and ...
A supercritical fluid (SCF) is a substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. [1] It can effuse through porous solids like a gas, overcoming the mass transfer limitations that slow liquid transport through such ...
Nitrogen is a liquid under −195.8 °C (77.3 K).. In physics, cryogenics is the production and behaviour of materials at very low temperatures.. The 13th International Institute of Refrigeration's (IIR) International Congress of Refrigeration (held in Washington DC in 1971) endorsed a universal definition of "cryogenics" and "cryogenic" by accepting a threshold of 120 K (−153 °C) to ...