Critical Temperature to Dielectric Degradation of Printed Circuit Board
Dielectric degradation of printed circuit board based on the thermal properties in an open-air environment was investigated. With increase of the temperature, the copper electrodes were oxidized from Cu 2O to CuO; the base material of epoxy laminate was thermally affected to the change of molecular structure and degradation of dielectric properties. With increase of the temperature, the capacitance and surface resistance decreased, the thermal stimulated current increased and showed a valley value near 450 K and a peak value near 490 K
Thermally stimulated discharge currents in high temperature dielectrics
The measurement of TSD (thermally stimulated discharge) currents in Nomex is reported. The TSD currents were measured by heating the sample at a uniform rate. Both the temperature and the current were measured using a strip chart recorder having a sensitivity of 2 mu V/mm and 10/sup -14/ A/mm, respectively. Detailed results are presented.<<ETX>>
Repressive coping before and after diagnosis of breast cancer
Objective: The aim was to investigate to which extent emotional repression is a premorbid coping tendency of cancer patients and/or a coping response to the threat posed by a cancer diagnosis. The results of one previous study of breast cancer patients suggest the latter possibility, and our aim was to replicate and extend these findings.