7 research outputs found
Physical properties of thermoelectric zinc antimonide using first-principles calculations
We report first principles calculations of the structural, electronic,
elastic and vibrational properties of the semiconducting orthorhombic ZnSb
compound. We study also the intrinsic point defects in order to eventually
improve the thermoelectric properties of this already very promising
thermoelectric material. Concerning the electronic properties, in addition to
the band structure, we show that the Zn (Sb) crystallographically equivalent
atoms are not exactly equivalent from the electronic point of view. Lattice
dynamics, elastic and thermodynamic properties are found to be in good
agreement with experiments and they confirm the non equivalency of the zinc and
antimony atoms from the vibrational point of view. The calculated elastic
properties show a relatively weak anisotropy and the hardest direction is the y
direction. We observe the presence of low energy modes involving both Zn and Sb
atoms at about 5-6 meV, similarly to what has been found in Zn4Sb3 and we
suggest that the interactions of these modes with acoustic phonons could
explain the relatively low thermal conductivity of ZnSb. Zinc vacancies are the
most stable defects and this explains the intrinsic p-type conductivity of
ZnSb.Comment: 33 pages, 8 figure
Multimodal prevention of venous thromboembolic complications after total hip and knee joint endoprosthesis
Results of a study of the efficacy and safety of multimodal prevention of venous thromboembolic complications (VTEC) after total knee and hip joint replacement in 1623 patients are presented. Two studies were carried out: the first focused on determining patient preference for the route of administration (parenteral or oral) for the prevention of VTEC. The second study analyzed the efficacy and safety of postoperative drug prevention of VTEC in routine clinical practice. In both studies the prophylaxis was conducted in accordance with local protocols. The results demonstrate great potential of the modern methods of VTEC prevention and efficiency of new oral medications. The incidence of thromboembolic complications can be reduced through systematic compliance with the protocol