(1913 - 1997)
Político y economista. Su principal aporte teórico a la economía fue la diferenciación entre los conceptos de "crecimiento" y "desarrollo" que aparece por primera vez en su análisis acerca del libro de Raúl Lorenzo titulado El empleo en Cuba.
Natural and Exact Sciences
2005 | "Measurements of transport and granular structure in high critical temperature superconductors "
Main executives entity: Physics Department University of the Oriente
Other entities: Physics, University of Sao Pulo, Brazil
Main author: Pedro Demetrio Muné Bandera (Departamento de Física Universidad de Oriente)
Coauthors: Ernesto Govea Alcaide (Physics Departament Eastern University), Renato de Figueiredo Jardim (Institute of Physics, University of Sao Paulo, Brasil).

The granularity of polycrystalline high critical temperature superconductors (HCTS) is the coexistence of different superconductor levels in a same material, each of which is characterized by a group of critical parameters. The granular structure of polycrystalline HCTS is the space distribution of superconductor levels and their critical parameters, which is of great interest in fundamental and applied aspects. Previous studies by means of transport measurements have distinguished two levels: to) intragranular or strong and b) intergranular or weak.

Such studies have been mainly based on critical current density measurements in low magnetic fields (<50mT). However, a systematic study, varying the elaboration methods to influence the space distribution of superconductor levels inside the sample, and this way to study their evolution, has not been previously reported. It is approached in this study the granularity of HCTS through critical current density measurements in low magnetic fields, J c (B a), magnetoresistance, (B a), and resistivity according to temperature, p (T) in polycrystalline samples with very similar intragranular and different intergranular properties.