We have carried out optical spectroscopic measurements of emission lines for a sample of Galactic plan- etary nebulae with Wolf-Rayet (WR) stars and weak emission-line stars (wels). The plasma diagnostics and elemental abundance analysis have been done using both collisionally excited lines (CELs) and optical recombination lines (ORLs). It was found that the abundance discrepancy factors (ADF = ORL/CEL) are closely correlated with the difference between temperatures derived from forbidden lines and those from He i recombination lines, implying the existence of H-deficient materials embedded in the nebula. The Hβ surface brightness correlations suggest that they might be also related to the nebular evolution.

ABSTRACT
1. INTRODUCTION
2. PLASMA DIAGNOSTICS
3. ABUNDANCE ANALYSIS
4. CONCLUSIONS
REFERENCES

• Ashkbiz Danehkar(Department of Physics and Astronomy, Macquarie University)
• Roger Wesson(European Southern Observatory)
• Amanda I. Karakas(Research School of Astronomy & Astrophysics, Australian National University)
• Quentin A. Parker(Department of Physics and Astronomy, Macquarie University/Australian Astronomical Observatory)