1. XRD INVESTIGATION OF THERMAL DEGRADATION EFFECT ON SOME COMMERCIAL PET SAMPLES. Authors: CARMEN NICULĂESCU, Z. KOVACS-KRAUSS, M. TODICA.2. XRD AND IR INVESTIGATIONS OF SOME COMMERCIAL POLYSTYRENE SAMPLES THERMALLY DEGRADED. Authors: CARMEN NICULĂESCU, LOREDANA OLAR, RĂZVAN STEFAN, MIHAI TODICA, CORNEL-VIOREL POP.3. FLUORESCENCE INVESTIGATION OF SOME POLYSTYRENE SAMPLES THERMALLY DEGRADED. Authors: MIHAI TODICA, CLAUDIU LUNGU, IOANA BREZESTEAN, CARMEN NICULĂESCU.