High-temperature super conductor

Photoacoustic method can be applied any types of shapes and states of the sample and also to non-destructive depth-profiling. Thus this finding expands the methodology of EXAFS much wider than before. High temperature super conductor, biological samples and other varieties can be studied. 

Hermann, A.M. and J.V. Yakhrni Thallium-Based High-Temperature Super Conductors, Marcel Dekker, Inc., New York, NY, 1994. 

Examples are the determination of (1) the CuA and Ba/Y ratios in YBCO (YBa2Cu306 + a), which strongly influence the resistivity of this high-temperature super conductor and (2) the mass thickness of Al, AI2O3, or TiOi layers on PET foil, assuming the stoichiometry mentioned, which improve the water-and airproof characteristics of this packing material. 

Part VI, 1991. High temperature-super conductor YBaaCusO , Prakt. Metallogr. 

Thallium and its compounds are extremely toxic as a result, they have few industrial uses. One possible use, however, is in high-temperature super conductors. For example, a thallium-based ceramic with the approximate formula Tl2Ba2Ga2Cu308+x exhibits superconductivity at temperatures as... 

This suggestion theoretically explains the metal and intermetallic compound superconductivity phenomenon (J. Bardin, L.N. Cooper and R. Schrieffer, Nobel Prize 1972), discovered earlier by H. Kamerling-Onnes (Nobel Prize, 1913). This phenomenon occurs only at very low temperatures (—20 K). However, superconductivity has been discovered in nonmetalhc, oxide-type chemical compounds with critical points of superconductivity up to ==140 K (in hquid nitrogen region) (so-called high-temperature super conductors, HTSC) (J.G. Bednorz and K.A. Muller, Nobel Prize, 1987). Intensive attempts to synthesize new materials of this kind are in progress. 

Use Metallurgical additive, high-temperature electrical conductor, refractory, cermet component, coatings resistant to attack by molten metals, aluminum manufacture, super alloys. 

E. Kaldis Oxygen nonstoichiometry and lattice effects in YBa2Cu30x. In Handbook on the Physics and Chemistry of Rare Earths, High-Temperature Super- 2.A1 conductors II., Vol.31, ed. by K. A. Gschneidner Jr.,... 

Reactions do not necessarily proceed uniformly, and uneven rates of reaction can lead to poor product quality and increased byproducts. Some intensified reactor types overcome the lack of uniformity of performance by careful design, but larger reactor vessels are inhwently non-isothermal. This can be overcome by attempting to move heat from those most exothermic parts of the reaction to areas where the reaction is less fast. The heat pipe (see Chapter 11) is a passive heat transfer device that can be used to implanent this in a reactor. Sometimes called a super thermal conductor , the heat pipe uses an evaporation-condensation cycle to transfer heat over a distance with minimal temperature drop. The fluid in the pipe is selected to suit the reactor operating temperature liquid metals may be used for high temperature reactions (at 600 C to 1000 C plus), for instance. 

The data in Table 1 also illustrate several additional facets of solid state ionic conduction. First the fast (or super ) ion conductors are charaeterized by very low activation energies for conduction (12-36 kj/mol) compared to the normal ionic conductors (> 60 kJ/mol). The low activation energy for superionic conduction is a major contributing factor to the high ionic conductivity at relatively low temperatures. 

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