Several dolomitic authigenic carbonate concretions (ACCs) are preserved in the Pliocene foreland sequence in southwestern Taiwan. Carbon isotopic signatures and the morphology of these carbonates and associated chemosymbiotic bivalve fossils reveal their methane seep origin. There are three types of ACCs: (1) massive brecciated blocks (MBBs; δ Atmos. Ocean. Sci., 24, 971-984, doi: 10.3319/TAO.2013.07.05.01(TT)

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The characteristics of a low power 50 Hz argon plasma for surface treatment of polytetrafluoroethylene (PTFE) film is presented in this article. The current-voltage behavior of the discharge and time-varying intensity of the discharge showed that a DC glow discharge was generated in reversed polarity at every half cycle. At discharge power between 0.5 to 1 W, the measured electron temperature and density were respectively 2-3 eV and ~10^8 cm^-3. The optical emission spectrum of the argon plasma showed presence of some ‘impurity species’ such as OH, N2 and H, which presumably originated from the residual air in the discharge chamber. On exposure of PTFE films to the argon glow plasma at pressure 120 Pa and discharge power 0.5 to 1 W, the water contact angle reduced by 4% to 20% from the original 114° at pristine condition, which confirms improvement of its surface wettability. The increase in wettability was attributed to incorporation of oxygen-containing functional groups on the treated surface and concomitant reduction in fluorine as revealed by the XPS analysis and increase in surface roughness analyzed from the Atomic Force micrographs. Ageing upon storage in ambient air showed retention of the induced increase in surface wettability.