Surface Corona Discharge Research Articles

Nanosecond Surface Corona Discharge for Different Types of Strip Electrodes and Ceramic or Polymer Dielectrics

Surface corona discharge characteristics from single-stripped and multi-stripped electrodes on the surface of thin dielectric plates of different kinds of ceramics and polymers are presented. Experimental results are obtained with voltage pulses of microsecond and nanosecond duration and they show significant difference in the values of the inception voltage, the discharge structure and current impulse amplitude for different barrier materials. Analysis of calculated and experimental values of the inception voltage is given, and it shows that beside electrical characteristics such as the relative permittivity e and the specific resistance of the barrier material, the surface properties of the barrier, its thickness and its structure play a significant role in the discharge appearance and development. Nanosecond applied voltage pulses give a more dense and uniform discharge structure than microsecond ones, other conditions being equal.

Immobilization of glucoamylase on ceramic membrane surfaces modified with a new method of treatment utilizing SPCP–CVD

Glucoamylase, as a model enzyme, was immobilized on a ceramic membrane modified by surface corona discharge induced plasma chemical process–chemical vapor deposition (SPCP–CVD). Characterizations of the immobilized enzyme were then discussed. Three kinds of ceramic membranes with different amounts of amino groups on the surface were prepared utilizing the SPCP–CVD method. Each with 1-time, 3-times and 5-times surface modification treatments and used for supports in glucoamylase immobilization. The amount of immobilized glucoamylase increased with the increase in the number of surface modification treatments and saturated to a certain maximum value estimated by a two-dimensional random packing. The operational stability of the immobilized glucoamylase also increased with the increase in the number of the surface treatment. It was almost the same as the conventional method, while the activity of immobilized enzyme was higher. The results indicated the possibility of designing the performance of the immobilized enzyme by controlling the amount of amino groups. The above results showed that the completely new surface modification method using SPCP was effective in modifying ceramic membranes for enzyme immobilization.

Film formation by motion control of ionized precursors in electric field

A chemical vapor deposition (CVD) method, called ionization CVD, in which ionized source molecules were deposited on a substrate by Coulombic force, was developed to control gas-phase reaction and film morphology. This method was applied to the tetraethylorthosilicate (TEOS)/ozone-atmospheric pressure chemical vapor deposition process by using the surface corona discharge. TEOS/O3 films deposited on SiN and SiO2 films by this CVD method showed good properties for the flow shape, the gap filling and the surface morphology. In Fourier-transform infrared spectra of gas-phase intermediates collected in the vapor condenser, the intensity of the absorption peak at 600 cm−1 was different between ionized intermediates and nonionized intermediates.

Visualization of EHD Fluid Motion Induced by Surface Corona Discharge

Visualization of EHD Fluid Motion Induced by Surface Corona Discharge

針電極を持つ高誘電率セラミックスを用いた沿面コロナによる生成電子密度

針電極を持つ高誘電率セラミックスを用いた沿面コロナによる生成電子密度

Simultaneous measurements of wire electrode surface contamination and corona discharge characteristics in an air-cleaning electrostatic precipitator

Contamination of the corona wire in a wire-to-plate type air-cleaning electrostatic precipitator is studied experimentally. In order to enhance the contamination of wire, air containing dust is directly supplied to a part of the wire electrode. Spores of Lycopodium and cigarette smoke particles are used as test dusts. Simultaneous measurements of wire electrode optical images and corona discharge modes are carried out during contamination processes. Results show that corona discharge modes and optical emission from the wire electrode change with time due to the surface contamination, in the case of cigarette smoke, after a time elapsed, streamer coronas appear due to the buildup of smoke particles on the wire surface. After the first streamer generation, the corona current fluctuates with time because the formation and diminution of the projections occur alternately at the different parts on the wire electrode surface.

Surface corona discharge excited rare gas halide lamps

A simple surface corona discharge excitation technique has been used to generate high repetition rate, high average power rare gas halide UV lamp radiation. The lamp exhibited reliable performance with very low jitter and high shot to shot reproducibility. An average power of 9 W of UV centered at 248 nm (KrF) was obtained from a small 7.0-cm-diam emitting surface. XeCl lamp lifetimes of over one billion shots were obtained on a single gas fill without the need for gas circulation or cryogenic cleanup.

Immobillzation of a bio-catalyst (enzyme) on a ceramic surface treated by the SPCP-CVD method

A novel method using a chemical vapor deposition (CVD) surface treating method was studied to introduce organic groups, which can be utilized for enzyme immobilization, onto ceramic surfaces. SPCP-CVD is a kind of CVD reaction using surface corona discharge for activation of the reactive gas. Using this method, a CVD reaction which was fed organo silicic compounds could prepare a silica thin film with remaining aminopropyl groups on the ceramic surface. It was shown that the enzyme was immobilized effectively on this remaining organic group by the glutaraldehyde cross-linkage method.

Pre-preionization of a long optical pulse magnetic-spiker sustainer XeCl laser

A novel preionization technique which uses a surface corona discharge to produce preionization electrons for the controlled low jitter breakdown of a main corona-gap preionizer is described. The pre-preionization scheme has been used to reliably preionize a long optical pulse (450 ns full width at half-maximum) XeCl laser. The laser excitation circuit is a new version of the overshoot mode of magnetic-spiker sustainer excitation specifically designed to be simple, reliable, and capable of high repetition rate operation.

Optical free induction decay (OFID) 10 μm co 2 laser systems

This paper describes new unproved and reliable optical free induction decay (OFID) picosecond-pulse CO 2-10 μm laser systems, differing mainly in the pump laser and in the peak power of the generated pulses. In this context a single-mode TEA-CO 2-10 μm laser preionized by a novel surfacecorona discharge was developed. Our improved plasma shutters operate as optical switches at variable gas pressures. They are triggered either by a laser-produced surface plasma or by an electrical high voltage discharge. With respect to the first trigger scheme we found new target materials for the surface plasma generation, i.e. metallized graphites. In the second scheme the electrical discharge is initiated by the TEA-laser pulse via a new laser-triggered spark gap. Single-mode TEA-CO 2-10 μm laser, plasma shutter plus a spectral filter form the OFID laser system, which generates the picosecond pulses. An electronic control completes the system as reliable working tool. Each of the OFID laser systems developed is capable to produce 10 μm pulses with a duration of 30–300 ps. Numerical calculations are performed to estimate the influence of various parameters on pulse shape and duration. Since a direct measurement of the time variation of the short pulses by fast IR detectors is not possible, we measure the picosecond pulses by means of an optical autocorrelation method with optical second harmonic generation. For the first time this is performed with polycrystalline material, e.g. GaAs or ZnSe, instead of a single crystal, e.g. GaAs or Te.

Corona-preionized nitrogen laser with variable pulse width

A simple method of producing pulsed coherent radiation at 337.1 nm with variable pulse durations of 2.0–3.5 ns using a small transversely excited N2 laser is described. For laser operation in a moderately broad range of gas pressure (up to 1 atm), a weak surface corona discharge has been utilized as a preionizer. The electrical excitation is a flat plate Blumlein circuit with the main electrodes fixed at a height of 35 mm above the corona streamers. The laser produces an output peak power in excess of 70 kW at 350 Torr gas pressure and pulse repetition rate of 10–50 Hz.

Compact, simple, high-energy, discharge-pumped rare gas halide laser

A simple, lumped capacitor, avalanche discharge excimer laser has been developed which uses a single spark array preionization rod located under a grid electrode to preionize the discharge region. A surface corona discharge is found to play an important role in achieving a more uniform transverse preionization. On KrF, energy in excess of 0.5 J is obtained (≳2.4 J/1) with a wide (16 × 25 mm) uniform beam of good divergence (1.8 × 5 mrad) and electrical efficiency above 1%.