The properties of excited xenon atoms in the discharge cells of a plasma display panel are investigated by measuring the excited atom density via laser absorption spectroscopy. The density of the excited xenon atoms in the metastable state increases from zero, reaches its peak, and decreases with time in the discharge cells, as expected from a theoretical model. The profile of an excited xenon atom is also studied in terms of the xenon mole fraction. The typical density of excited xenon atoms in a metastable state is on the order of 1013 atoms/cm3.

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A thick ZrC layer was successfully coated on top of a SiC buffer layer on carbon/carbon (C/C) composites by vacuum plasma spray (VPS) technology to improve the ablation resistance of the C/C composites. An optimal ZrC coating condition was determined by controlling the discharge current. The ZrC layers were more than 70 µm thick and were rapidly coated under all spraying conditions. The ablation resistance and the oxidation resistance of the coated layer were evaluated in supersonic flames at a temperature exceeding 2000 °C. The mass and linear ablation rate of the ZrC-coated C/C composites increased by 2.7% and 0.4%, respectively. During flame exposure, no recession was observed in the C/C composite. It was demonstrated that the ZrC coating layer can fully protect the C/C composites from oxidation and ablation.

The exited Xe atoms in the 1s 5 metastable state and the 1s 4 resonance state across the two sustaining electrode have been monitored in a micro-discharge cell of alternating current plasma display panels (PDPs) by laser absorption spectroscopy. In this study, it is found that the maximum excited xenon density is 5 4 10 12 cm 3 in the 1s 5 metastable state and 1 2 10 12 cm 3 in the 1s 4 resonance state for the PDP cell with gap distance of 150 m and width of 350 m under the fixed gas pressure of 350 torr and a mixture of Xe content ratio of 10% with Ne under driving frequency of 35 kHz. It is also observed that the exited Xe atom density and the plasma ion density are strongly correlated with one another in this experiment. It is noted that the plasma ion density reaches a minimum at the center of electrode gap and a maximum of 9 0 10 11 cm 3 in a region located 200 m away from this center under the filling pressure of 350 torr, which corresponds to the strongest discharge in alternating current plasma display panel (ac-PDP). When increasing PDP driving frequency from 35 kHz, 50 kHz up to 100 kHz, it is found that density of excited Xe atom in the 1s 5 metastable state increase from 6 5 10 12 cm 3 up to 1 39 10 13 cm 3Index Terms-Alternating current plasma display panel, excited Xe atom, laser absorption spectroscopy, metastable state, plasma ion density, resonance state.

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