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An inactivation mechanism of A549 cancer cells is studied by using a dielectric barrier discharge (DBD) plasma needle. The influence of oxygen concentration, which is injected into helium plasma afterglow region through a stainless steel tube, is investigated. The neutral red uptake assay provides a qualitative observation of morphological differences between the dead cells and the viable cells after plasma treatment and a quantitative estimation of cell viability under different conditions. In the treatment process at a fixed power of 24 W, the inactivation efficiency of helium-oxygen plasma depends mainly on the exposure time and percentage of added oxygen in helium plasma. Experimental results show that the best parameters of the process are 150 s treatment time, 800 mL/min He with 3% O2 addition and separation of needle-to-sample 3 mm. According to the helium-oxygen emission spectra of the plasma jet, it is concluded that the reactive species (for example, OH and O) in the helium-oxygen plasma play a major role in the cell deactivation.

Supper hard and wear resistant titanium nitride films were deposited onto 0.45% carbon steel substrate by pulsed high-energy-density plasma(PHEDP) technique at ambient temperature. The microstructure, surface compositions and depth profile of the film were analyzed by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES) and scanning electron microscopy (SEM).The hardness profile and tribological behavior of the film were determined with nano-indenter and MM200 wear tester, respectively. The results showed that the microstructure of the film was dense and uniform and mainly composed of titanium nitride phases. A wide mixing interface existed between the film and the substrate. The film possessed a very high value of nanohardness. The wear resistance of the film was excellent and the value of the friction coefficient of the film was low under dry sliding wear test conditions.

Using the new inner surface modification technique named GEPSⅡ(grid-enhanced pl asma source ion implantation), which is designed for inner surface modification of tubular work piece, has successfully produced TiN coating on 0.45% C steel (4 5# steel). By comparing with the uncoated 45# steel sample, the electrochemical corrosion test on the coated 45# steel samples presents about 5—10 times improv ement in their corrosion resistance. Structural analysis shows that the TiN coat ings have preferred crystal orientation(111) and (2000). And the depth of coatin gs is about 20 nm, with part of which embedding in the substrate.