[Investigation on Spectral Characteristics of Micro-Gap Dielectric Barrier Uniform Discharge in Air].

The plasmas generated by dielectric barrier discharge in atmospheric pressure air have wide application prospect in industry. In order to study generation condition and mechanism, the dielectric barrier uniform discharge in atmospheric pressure air has been studied experimentally with a micro-gap discharge device. Results of electrical characteristics indicate that it exist several current pulses with short width in half period of the applied voltage at a low voltage, a large number of micro-discharge filaments are observed.

[Glow Discharge Characteristics of Hollow Needle-Plate Electrode in Atmospheric Pressure Argon].

Atmosphere pressure uniform plasma has the broad application prospect in the industrial field. Using hollow needle cathode-plate anode device excited by direct-current voltage, a uniform and stable glow discharge is generated at atmospheric pressure in ambient air with argon used as working gas. The influence of the experimental parameters (including gas flow rate and the gas gap width) on discharge has been investigated by optical method.

[Investigation of a jet operated in atmospheric pressure argon by optical emission spectroscopy].

A uniform plasma plume was generated in a coaxial dielectric barrier discharge jet through blowing argon into the ambient air at atmospheric pressure. The plasma plume was uniform along the direction of the gas flow. The length of the plasma plume was investigated as a function of the peak voltage, the driving frequency and the gas flow rate.

[Spectroscopic characteristics of DC excited atmospheric pressure glow discharges generated in a needle-plate electrode device and a needle-water electrode one].

Glow discharge characteristics in two discharge devices, i.e. in a needle-plate electrode geometry and a needle-water electrode one were compared by using spectroscopic method.

[Spatial distribution of electrons with high energy in atmospheric pressure glow discharge excited by DC voltage].

Atmospheric pressure glow discharge excited by a DC voltage was realized in a 6 mm air gap by using a needle-water electrode discharge device. The atompheric pressure glow discharge has characteristic regions such as a cathode fall, a negative glow, a Faraday dark space, a positive column and an anode glow. The discharge is a normal glow through analyzing its voltage-current curve.

[Vibrational temperature of plasma plume in atmospheric pressure air].

A tri-electrode discharge device was designed in a dielectric barrier discharge configurations to generate a fairly large volume plasma plume in atmospheric pressure air. The discharge characteristics of the plasma plume were investigated by an optical method. The discharge emission from the plasma plume was collected by a photomultiplier tube.

[Measurement of active particles generated in a coaxial barrier discharge by spectral method].

Coaxial dielectric barrier discharge has extensive application prospects. A dielectric barrier discharge device with water electrode was used to investigate the discharge properties and spectral intensity emitted from active particles in the air by optical method. Results indicate that the optical emission spectra consist of spectral lines from oxygen atoms (777.

[Comparative investigation of the discharge characteristics of a single needle jet and needle-plate jet].

In the present paper, discharge characteristics were studied in atmospheric pressure argon by a single needle jet and needle-plate jet through combination of optical measurement and electrical one. Results show that the length and cross-sectional area of the plasmas generated in the two jets increase with increasing the peak value of the applied voltage. The cross-sectional area generated by needle-plate jet is bigger than that of the single needle jet at the same voltage.

[Spectral intensity distribution of oxygen atom in a plasma plume].

Low temperature plasma generated in plasma plume discharge at atmospheric pressure has prosperous application fields in industry because the vacuum device can be dispensable and some complex materials can be treated in three dimensions by this plasma plume. A stable plasma plume was generated in atmospheric pressure air in the present paper by using a plasma needle discharge device. It was found by spectral measurement that there are some spectral lines emitted from oxygen atom such as 777.

[Investigation of the vibrational temperature and gas temperature in gas discharge generated by plasma needle].

Low temperature plasma generated by plasma needle in atmospheric pressure air has extensive application prospects in industry because the vacuum device can be dispensable. In the present paper a stable plasma plume was generated in air by using a plasma needle device. The vibrational temperature and gas temperature were investigated for the plasma plume by optical spectroscopic method.

[Comparative study on the gas temperature of a plasma jet at atmospheric pressure].

A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce jet plasma in flowing work gas (argon mixed with trace nitrogen) at atmospheric pressure. The relation between the plasma length and the gas flow rate was obtained by taking the images of the jet plasma. A high-resolution optical spectrometer was used to collect the optical emission spectrum.

[Investigation on the gas temperature of a plasma jet at atmospheric pressure by emission spectrum].

A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce plasma plume in atmospheric pressure argon. Spatially and temporally resolved measurement was carried out by photomultiplier tubes. The light emission signals both from the dielectric barrier discharge and from the plasma plume were analyzed.

[Determination of electric field distribution in dielectric barrier surface glow discharge by spectroscopic method].

In the present paper, stable glow discharges were obtained in air at low pressure with a dielectric barrier surface discharge device. Light emission from the discharge was detected by photomultiplier tubes and the research results show that the light signal exhibited one discharge pulse per half cycle of the applied voltage. The light pulses were asymmetric between the positive half cycle and the negative one of the applied voltage.

[Study on the characteristics of dielectric barrier discharge at atmospheric pressure by spectroscopic method].

In the present paper, stable discharges were respectively obtained in air and helium at atmospheric pressure with a dielectric barrier discharge device consisting of water electrodes. By comparing the discharges in the two gases, it was found that the discharge in air at atmospheric pressure is not uniform and micro-discharges can be discerned which are distributed on the electrode stochastically, while the discharge in helium at atmospheric pressure is quite uniform and no discharge filament can be discerned. Comparing the two kinds of discharges, the plasma generated in helium discharge at atmospheric pressure has better prospect for application in industry because of its uniformity.