We prepared Bi
2Sr
2Ca
2Cu
3O
x
(2223-phase) superconducting ceramics by a solid-state reaction method in various oxygen-reduced atmospheres, and investigated the optimum preparation condition for ...single 2223-phase ceramics. The samples prepared at the temperature by 30 °C lower than the melting point in the atmospheres of Ar:O
2=6:1 showed the superconducting transitions at 110 K and the zero resistance temperature above 90 K. From the results of X-ray diffraction, we found that the volume fraction of 2223-phase in the ceramics increased with the sintering temperature in the range of temperatures less than melting point.
The charge-state distributions of U238 with energies of 14 and 15MeV/nucleon were measured using nitrogen (N2 ) gas and carbon foil (C-foil) charge strippers. The most probable charge states of U238 ...with energies of 14 and 15MeV/nucleon in N2 gas attain equilibrium at 60.8 and 62.4, whereas those in C-foils attain equilibrium at 75.8 and 76.7, respectively. Novel empirical formulas for the accurate prediction of the equilibrium charge states of U238 with energies 10–20MeV/nucleon in gases and C-foil were derived by fitting the data in the energy range of 1–20MeV/nucleon . The charge states predicted by using the formulas for gases and C-foil are in good agreement with the data in the energy range of 10–20MeV/nucleon within an average of 0.23 and 0.21, respectively.
We prepared high quality Bi sub(2)Sr sub(2)CaCu sub(2)O sub(y) (2212-phase) superconducting single crystals by a self-flux method using two kinds of starting powders. Holding process was added to ...cooling process during the crystal growth. Plate-like 2212-phase single crystals were prepared at the cooling rate of 3 degree C/h by employing a temperature holding process. The size of the single crystals was nearly equal to those of the crystals prepared at the cooling rate of 1 degree C/h. This may indicate that the employment of the holding process is effective in achieving a large growth rate of 2212-phase single crystals. copyright 2001 Elsevier Science B.V. All rights reserved.
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