Showing papers by "Northeastern University (China) published in 1987"
TL;DR: In this article, annealing in air or oxygen in the range 350-450/sup 0/C produced material which analyzed as 6.94 (2) and 6.15-6.60, respectively.
Abstract: On the basis of iodometric determinations of the oxidation state of Cu in YBa/sub 2/Cu/sub 3/O/sub 7-x/, TGA experiments, and equilibrium reactions, the highest oxygen content of 6.96 (2) is achieved when annealing in O/sub 2/ at about 440/sup 0/C. Annealing in air or oxygen in the range 350-450/sup 0/C produced material which analyzed as 6.94 (2). The orthorhombic phase exists over the composition range O/sub 6.96/-O/sub 6.60/. The tetragonal composition YBa/sub 2/Cu/sub 3/O/sub 6/ is prepared by heating the mixture in an inert atmosphere, Ar or N/sub 2/, at temperatures in excess of 700/sup 0/C. The oxygen solution range for this phase ranges from O/sub 6.0/ to O/sub 6.15/. Compositions with nominal oxygen contents of 6.15-6.60 may be mixtures of the tetragonal and orthorhombic phases.
181 citations
TL;DR: In this paper, it was observed that water droplets in emulsions have an inherent vibration and this is believed to promote the coalescence of the particles, and high-speed photography showed the coalescing time to be less than 1 1500 s.
12 citations
7 citations