chemia - Studia

DUMITRITA MOLDOVAN, MIHAELA POP, RADU FECHETE, ANNE BAUDOUINE , MIHAI TODICA
For the saturation recovery (see Figure 3c) the number of saturating
pulses was 10 while the scans number was reduced at 64 [9]. The recovery
time, τ 1 was increased from 1 ms with a ratio of 1.1 in unevenly 85 steps up
to 3 s. In all measurements the temperature was set to 35 o C. Finally, in order to
find the transverse T 2 and longitudinal T 1 relaxation times distributions, the
CPMG decays and saturation- recovery build-up curves were analyzed
using the well know UPIN algorithm, which perform a Laplace inversion of
the measured data [10]. The HDPE samples were aged using various
agents and different conditions: i) the dose of irradiation with gamma ray
was 8989 Gy accumulated during 1696 h at a 5,3 Gy/h; ii) the accumulated
dose of irradiation with X-ray was 358 Gy during 12 days; iii) HDPE was
melted at a temperature of 256 o C during 24 h and then cooled at a room
temperature; iv) HDPE was sinked into liquid nitrogen at -196 o C for 5 min
and then heated at room temperature.
ACKNOWLEDGMENTS
DM and RF thank to CNCS PN II Idei program for the support. MP
acknolwedges financial support from a program co-financed by The SECTORAL
OPERATIONAL PROGRAMME HUMAN RESOURCES DEVELOPMENT,
Contract POSDRU 6/1.5/S/3 – „Doctoral studies: through science towards
society" and CNRS-University Lyon-1, Service RMN du Solide.
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