Dan Ungureanu

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The Transmission System Operator (TSO) is responsible for the power system operation. It has to provide the transmission network maintenance and development, having as a goal the safety, reliable and economical operation of the power system. Additionally, it has to fulfil the environment constraints and, most important, to support the development of the(More)
In this paper we present a synthesis method for obtaining hydroxyapatite nanopowders by chemical precipitation. As the starting reagents, analytical grade Ca(OH)2, H3PO4 and NH4OH were used. The proposed method led to obtaining a hydroxyapatite with a high degree of crystallinity and purity. The crystallinity degree was great than 90%, in case of sample(More)
Polyacrylonitryle (PAN) fibers are used on a large scale in textile industry but, some sorts of PAN fibers are valuable precursors for specific carbon fiber (CF) due to their best fitness to the purpose e.g. for high strength CF or for active CF. The application of PAN as precursors of CF is based on its specific structure and texture. Thus, the properties(More)
In this paper we present a synthesis method for obtaining hydroxyapatite nanopowders by chemical precipitation. As the starting reagents, analytical grade Ca(OH)2, H3PO4 and NH4OH were used. The proposed method led to obtaining a hydroxyapatite with a high degree of crystallinity and purity. The synthesized samples were characterized by X-ray diffraction(More)
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