High-temperature super

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. 

The small tip angle NMR techniques recently developed by Pennington et 124-126 allowed them to measure nuclear spin-spin couplings between neighbouring and nuclear spins in the high-temperature super-... 

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. 

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.,... 

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. 

For reasons that are not fiiUy understood, PPSF exhibits generally improved compatibiUty characteristics over either PSF or PES in a number of systems. An example of this is blends of PPSF with polyaryletherketones (39,40). These blends form extremely finely dispersed systems with synergistic strength, impact, and environmental stress cracking resistance properties. Blends of PPSF with either PSF or PES are synergistic in the sense that they exhibit the super-toughness characteristic of PPSF at PSF or PES contents of up to 35 wt % (33,34). The miscibility of PPSF with a special class of polyimides has been discovered and documented (41). The miscibility profile of PPSF with high temperature (T > 230° C) polysulfones has been reported (42). 

In the last chapter we said that one of the requirements of a high-temperature material - in a turbine blade, or a super-heater tube, for example - was that it should resist attack by gases at high temperatures and, in particular, that it should resist oxidation. Turbine blades do oxidise in service, and react with H2S, SO2 and other combustion products. Excessive attack of this sort is obviously undesirable in such a highly stressed component. Which materials best resist oxidation, and how can the resistance to gas attack be improved ... 

Ceramies are quite tolerant of sueh eontaminants as sodium and vanadium, whieh are present in low-eost fuels and highly eorrosive to eurrently used niekel alloys. Ceramies are also up to 40% lighter than eomparable high-temperature alloys—another plus in applieation. But the biggest plus is material eost. Ceramies eost around 5% the eost of super alloys. 

Finding that the scattering functions at low temperature are amenable to an MCT description, we are faced with a dilemma. On the one hand, the high-temperature mean-square displacement curves lead us to conclude that dihedral barriers constitute a second mechanism for time scale separation in super-cooled polymer melts besides packing effects. On the other hand, the... 

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