• Nuclear Engineering and Technology
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• v.52 no.11
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• pp.2535-2542
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• 2020

To understand the fundamental parameters of Alvand tokamak, A Rogowski coil with an active integrator was designed and constructed. Considering the characteristics of the Alvand tokamak, the structural and electrical parameters affecting the sensor function, were designed. Calibration was performed directly in the presence of plasma. The sensor has a high resistance against interference of external magnetic fields. Plasma current was measured in various experiments. Based on the plasma current profile and loop voltage signal, the time evolution of plasma discharge was investigated and plasma behavior was analyzed. Alvand tokamak discharge was divided into several regions that represents different physical phenomena in the plasma. During the plasma discharge time, plasma had significant changes and its characteristic was not uniform. To understand the plasma behavior in each of the phases, the Rogowski sensor should have sufficient time resolution. The Rogowski sensor with a frequency up to 15 kHz was appropriate for this purpose.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.764-767
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• 2003

We have experimentally investigated the influence of wall charge configurations prior to addressing discharge on dynamic margin in AC plasma display panel. In this experiment, we have analyzed the quantity and polarity of wall charge accumulated on the front and rear dielectrics just prior to the addressing discharge under the conventional driving sequence.

• Journal of the Korean Vacuum Society
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• v.15 no.6
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• pp.556-562
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• 2006

The plasma display panel is made of many small discharge cells, which consist of a discharge space between the cathode and anode. An electrical discharge occurs in the discharge space filled by neon and xenon gases. The electron temperature is determined from the sparking criterion, which theoretically estimates the electrical breakdown voltage in terms of the xenon mole fraction. The plasma in the cell emits vacuum ultraviolet lights of 147 nm and 173 nm, exciting fluorescent material and converting VUV lights to visible lights. The physical mechanisms of all these processes have been theoretically modeled and experimentally measured. The theory and experimental data agree reasonably well. However, new materials and better configuration of cells are needed to enhance discharge and light emission efficiency and to improve the PDP performance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.1
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• pp.13-19
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• 2002

The plasma display panel with the electrode structure of new discharge AND gate was proposed and the driving system for experiment was developed. And discharge AND gate operation was verified. Discharge AND gate operated by the operation speed of 8${\mu}\textrm{s}$ and the operation margin of 20V. It was known to be able to control the discharge of the adjoining scan electrode accurately. Because this method uses the DC discharge, the control of the discharge can be facilitated compared with conventional discharge AND gate. Moreover, because the input discharge and the output discharge of AND gate are separate, the display discharge can be prevented from passing AND gate. Therefore it is possible to app1y to the large screen plasma display. And the decrease of contrast ratio does not occur because the scanning discharge does not influence the picture quality.

• Journal of the Korean institute of surface engineering
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• v.56 no.6
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• pp.386-392
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• 2023

In this work, we describe the reduction kinetics of gold nanoparticles synthesized by plasma discharge in aqueous solutions with varied voltages and precursor (HAuCl₄) concentrations. The reduction rate of [AuCl₄]^- was determined by introducing NaBr to the gold colloidal solution synthesized by plasma discharge, serving as a catalyst in the reduction process. We observed that [AuCl₄]^- was completely reduced when its characteristic absorption peak at 380 nm disappeared, indicating the absence of [AuCl₄]^- for ligand exchange with NaBr. The reduction rate notably increased with the rise in discharge voltage, attributable to the intensified plasma generated by ionization and excitation, which in turn accelerated the reduction kinetics. Regarding precursor concentration, a lower concentration was found to retard the reduction reaction, significantly influencing the reduction kinetics due to the presence of active H⁺ and H radicals. Therefore, the production of strong plasma with high plasma density was observed to enhance the reduction kinetics, as evidenced by optical emission spectroscopy.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1579-1583
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• 2008

We proposed the new structure of ac plasma display panel(PDP) to improve the luminous efficacy and driving voltage characteristics. Through two-dimensional numerical simulations, we analyzed the effects of new counter discharge type, which consists of counter sustain electrodes and auxiliary electrodes. Generally, an advantage of AC PDP with the counter sustain electrodes has been known for the driving characteristics of the low voltage. In this work, the new counter structure using the ignition discharge by the auxiliary pulse applied to the address electrode showed the result of the increased luminous efficacy. The short gap discharge between two auxiliary electrodes on the front plate could intensity the long gap discharge between counter electrodes. The reliability of simulation result could be confirmed by the experimental result in the test panel.

• Journal of the Korean Vacuum Society
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• v.13 no.3
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• pp.132-138
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• 2004

We used the self-consistent one-dimensional model applied to FCT algorithm and FEM method in a wire-cylinder type reactor to study the characteristics of corona discharge plasma in air at the atmospheric pressure. At the pulsed do voltage and do voltage, we studied the changes of the characteristic of plasma by computing electron density profile according to the changes of voltage and the size of reactor. The changes of active radius from this result are compared with the data of Peek's. The numerical simulation results for a corona discharge plasma explain the physical mechanism of the discharge process and could be used to obtain the optimized parameters for designing the plasma reactor for pollution abatement.

• Journal of Environmental Science International
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• v.26 no.6
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• pp.711-717
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• 2017

Dielectric Barrier Discharge (DBD) plasma is a new technique for use in environmental pollutant degradation, which is characterized by the production of hydroxyl radicals as the primary degradation species. Due to the short lifetime of the chemically active species generated during the plasma reaction, the dissolution of the plasma gas has a significant effect on the reaction performance. The plasma reaction performance can be enhanced by combining the basic plasma reactor with a homogenizer system in which the bubbles are destroyed and turned into micro-bubbles. For this purpose, the improvement of the dissolution of plasma gas was evaluated by measuring the RNO (N-dimethyl-4-nitrosoaniline, an indicator of the generation of OH radicals). Experiments were conducted to evaluate the effects of the diameter, rotation speed, and height of the homogenizer, pore size, and number of the diffuser and the applied voltage on the plasma reaction. The results showed that the RNO removal efficiency of the plasma reactor combined with a homogenizer is two times higher than that of the conventional one. The optimum rotor size and rotation speed of the homogenizer were 15.1 mm, and 19,700 rpm, respectively. Except for the lowest pore size distribution of $10-16{\mu}m$, the pore size of the diffuser showed little effect on RNO removal.

• Applied Science and Convergence Technology
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• v.26 no.6
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• pp.195-200
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• 2017

A mobile lab kart for plasma training is developed with a high vacuum pumping system, vacuum gauges and a glass discharge tube powered by a high voltage transformer connected to a household 60 Hz line. A numerical model is developed by using a commercial multiphysics software package, CFD-ACE+ to analyze the experimental data. Simulations for argon and nitrogen were carried out to provide fundamental discharge characteristics. Variations of the kart configuration were demonstrated: a glass tube with three electric probes, optical emission spectrometer attachment and infra red thermal imaging system to give more detailed analysis of the discharge characteristics.

• KIEE International Transactions on Electrophysics and Applications
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• v.11C no.4
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• pp.107-112
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• 2001

Laser Thomson scattering measurements of electrom temperature and density in a neutral loop discharge (NLD) plasma were performed in order to reveal the electron behavior around the neutral loop (NL). The experimental results were examined by using a simulation model that included effects of a three dimensional electromagnetic field with spatial decay of the RF electric field, and the limitation of the spatial extent of the electron motion and collision effect. From the experiments and modeling of the electron behavior, it was found that NLD plasma posses the electron temeprature $T_{e}$ and density ne peaks around the NL is essential for the formation of plasma. Also, the optimum condition of plasma production could be simply estimated by the calculation of $U_{av}$ and $F_{0}$././.