Ou Qiongrong

Effect of Frequency on Emission of XeI* Excimer in a Pulsed Dielectric Barrier Discharge

Emission spectra of XeI* excimers and ultraviolet intensity at 253 nm from a dielectric barrier discharge (DBD) lamp excited by a pulsed voltage were measured as functions of pressure, electrical power, and frequency. In the DBD lamp driven by a higher frequency voltage, a more intense emission of XeI* excimers with high efficiency at 253 nm was found. A diffuse discharge mode was observed at high xenon pressure (>1 atm) with an excessive iodine concentration in the DBD driven by a high frequency (60 kHz) voltage.

Electrical Characteristics of Pseudoglow Discharges in Helium under Atmospheric Pressure

A pseudoglow discharge behaviour is achieved at a 2.0-mm dielectric-dielectric electrode gap in pure helium under atmospheric pressure. An experimental study of the pseudoglow discharges is presented. The electrical characteristics and the discharge photos of the pseudoglow discharges are analyzed and discussed. The current-voltage parameters of the pseudoglow discharges are considered in regard to the influence on their behaviour.

Plasma Induced Grafting of PSt onto Titanium Dioxide Powder

An investigation of grafting of polymer of styrene (PSt) onto titanium dioxide powder is reported in this paper. The graft polymerization reaction was induced by N2 plasma treatment on the surface of titanium dioxide. Infrared (IR) spectra and X-ray photospectrum (XPS) results showed that PSt was grafted onto the titanium dioxide powder. An observation by X-ray diffraction (XRD) spectra indicated that the crystal structure of the titanium dioxide powder was unchanged after the plasma treatment.

A Novel Continuously Initiated Polymerization by One-Atmosphere Low Temperature Plasma Device

A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.

Plasma Induced Grafting of PMMA onto Titanium Dioxide Powder

Grafting of polymer of methyl methacrylate (PMMA) onto titanium dioxide powder is investigated in this paper. The graft polymerization reaction is induced by dielectric-barrier-discharge produced N2 plasma treatment of titanium dioxide surfaces. IR, XPS and TGA results show that PMMA is grafted onto the surfaces of titanium dioxide powder. And crystal structure of the titanium dioxide powder observed with XRD spectra is unchanged after plasma graft polymerization.

High frequency discharge plasma induced grafting of polystyrene onto titanium dioxide powder

Grafting of polystyrene (PS) onto titanium dioxide powder was investigated. The graft polymerization reaction was induced by high frequency discharge produced N2 plasma treatment of the surfaces of titanium dioxide. IR, XPS and TGA results show that PS was grafted on the titanium dioxide powder. And the crystal structure of the titanium dioxide powder observed by XRD was unchanged after plasma treatment.

Large area planar plasma sustained by surface microwave

In this paper, we show theoretically and experimentally that the large-area planar plasma with high density and good uniformity can be sustained by a surface microwave when the electron density is over-dense. From the experimental results we find that the nonuniformities in azimuthal plasma density and electron temperature have been greatly improved and in particular the nonuniformity is less than 10% when the gas pressure is 30 Pa. By improving the antenna shape, enhancing the microwave power and choosing the appropriate gas pressure, the large area planar plasma with high density can be produced.

Influence of Iodine Vapour Pressure on Formation of XeI* in Xe/I2 Mixture

The influence of the iodine vapour pressure on the mechanisms of XeI* formation is investigated in Xe/I2 mixture by dielectric barrier discharge. The iodine vapour pressure is measured as a function of the ultraviolet (UV) intensity of XeI* emission at 253 nm, and found that the UV intensity reaches a maximum at 0.9 Torr of iodine at a xenon pressure of 300 Torr, then decreases slowly with the iodine pressure larger than 0.9 Torr. The discharge mode transforms from a hybrid discharge at a xenon pressure of 760 Torr with 1.0 Torr of iodine to a diffuse mode at 10 Torr of iodine. These results are quite different from those of other rare-gas halogen excimers and indicate a different mechanism of XeI* formation from those of other rare-gas halogen excimers.