Viscosity and sedimentation experiments were made for fractions of cellulose acetate CA (degree of substitution, D.S. = 2,46) in acetone and CA (D.S. = 2,92) in N,N-dimethylacetamide (DMAc) at 25 "C. The following empirical relations were established between the-sedimentation coefficient at infinite dilution so and the weight average molecular weight M,,,: so = 1,02 * G,$24 (s) for CA (D.S. = 2,92) in DMAc. From the analysis of the molecular weight dependence of so and the limiting viscosity number [ q ] (method 1 B) and the concentration-dependence parameter k, and [ q ] (method lE), the solvent draining parameter X was estimated to be less than 1, indicating that the free draining effect cannot beignored. The unperturbed chain dimension parameter A was determined from data on so and M, to be between 1,72. lo-' and 1,80 * cm for CA (D.S. = 2,46) in acetone and between 1,63. lo-' and 1,68. lo-' cm for CA (D.S. = 2,92) in DMAc. These values are in good agreement with those estimated by thermodynamic and viscometric approaches. %,$39 (s) for CA (D.S. = 2,46) in acetone and so = 1,83 .
Melting and crystallization experiments of InGaSb were done under the reduced gravity condition (102G) in an airplane and at the normal gravity condition (IG) in the laboratory. Crystallized InGaSb was found to contain many needle crystals in both the cases. Reduced gravity condition was found to be more conducive for crystal growth than the normal gravity condition. Formation of spherical projections on the surface of InGaSb during its crystallization was in-situ observed using a high speed CCD camera in the drop experiment. Spherical projections showed dependence of gravity during its growth. Indium compositions in the spherical projections were found to vary depending on the temperature.
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