RESUMO
Void filling in (I) Bi(x)-added Co(4)Sb(12) or (II) Sb/Bi substitution of Co(4)Sb(12-x)Bi(x) has been investigated for structural and thermoelectric properties evaluation. X-ray powder data Rietveld refinements combined with electron probe microanalyses showed a polycrystalline and practically Bi-free CoSb(3) skutterudite phase as the major constituent as well as a secondary Bi phase in the grain boundaries. For series I alloys, the electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature in the range from 450 to 750 K. The electrical conductivity of all the samples increased with increasing temperature, showing a semiconducting nature with smaller values of the Seebeck coefficient for higher Bi fractions. Conduction over the entire temperature range was found to arise from a single p-type carrier. Thermal conductivity showed a reduction with Bi added in all the samples, except for Bi(0.75)Co(4)Sb(12), and the lowest lattice thermal conductivity was found for a Bi-added fraction of 0.5. The maximum zT value of 0.53 at 632 K is higher than that of Co(4)Sb(12).
RESUMO
Focal neurological symptoms may provide the first clue to the presence of nonketotic hyperglycemia (NKH). We report a patient with hemichorea-hemiballism (HC-HB) as the first manifestation of NKH. CT Brain revealed hyperdensity in bilateral globus pallidus (GP) and putamen predominantly on right side. Blood sugar was 580 mg/dl and s. osmolality was 316 mosm/l. This condition resolved after correction of hyperglycemia. The possible mechanism by which NKH causes this condition is discussed.
