• 전기학회논문지
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• 제62권1호
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• pp.83-89
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• 2013

In order to reduce the power consumption in international standard IEC62087, the luminance efficiency should be improved at the low discharge load rather than at the high discharge load. Thus, this paper analysed the characteristics of the discharge at the panels with ITO Gap of $65{\mu}m$, $80{\mu}m$, and $100{\mu}m$ in 50-inch PDP with FHD resolution. It was well known that the long gap panel improves the luminance and the luminous efficiency. However, it is very difficult to drive the panel due to high driving voltage. When the normal driving method was applied at the panel with ITO gap of $100{\mu}m$, the phenomenon of the double peak was generated in the sustain period. We confirmed that main factor of the double peak is the self-erasing discharge. When the CLHS driving method was applied at the panel with ITO gap of $100{\mu}m$, the self-erasing discharge was improved in the sustain period. Also, the $V_S$ and $V_A$ minimum voltage of the CLHS driving method decreased about 9V and 12V compared with those of the normal driving method. Moreover, when the CLHS driving method was applied to the panel with ITO gap of $100{\mu}m$, the luminance and the luminous efficiency increased compared with those of the normal driving method. The luminance and the luminous efficiency greatly increased at the low discharge load. The less discharge load, the higher increase rate of the luminance and the luminous efficiency. Especially, the luminous efficiency at ITO gap of $100{\mu}m$ increased about 26.3% at the discharge load of 4% compared with that at ITO gap of $65{\mu}m$.

• Journal of Biosystems Engineering
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• 제22권3호
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• pp.303-310
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• 1997

Motivated by the need fir developing the new method of weed control in place of chemical weedicide, this paper aims at making good use of electricity against environmental pollution. Compared with chemical weedicide, the electric method of weed control is functionally more versatile, effectively more rapid, and lower in terms of cost. In particular, this method will contribute to environmental protection. In detail the electrical weed control system which is the simple circuit for generating the electric current of high voltage is comprised of step-up transformer which rectifies the current and the capacitor which stores the energy. The effectiveness of electrical weed control system is evaluated by germination rate and control of Dgitaria Sangvinalis(Galinsoga ciliate). As a result, the electrical weed control system(high voltage spark discharge) can kill weeds effectively

• Journal of Biosystems Engineering
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• 제8권2호
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• pp.26-38
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• 1983

Binder harvesters introduced to Korea were originally designed to be used for Japonica varieties which are highly resistant to shattering. In order to improve the performance of the binder to Indica varieties which are easily shattered and have shorter stem, mechanical modifications of the binder are inevitable. Shattering losses of the binder can be classified into two major parts; one incurred before and one after binding operations. The latter has been evaluated as great as the former. Previous studies indicated that the high discharge losses resulted from a great impact force of the discharge arm on the rice bundle during the discharge process. This study was intended to theoretically analyze the discharge mechanism of four-bar linkage. For this purpose, two commercially available binder harvesters having a four-bar linkage as a discharge mechanism were analyzed. Using the results from the motion analysis and the other structural constraints of the machines, they were modified and experimentally compared with the machines without modification to see whether any decrease in grain losses was obtained. The results obtained in this study are summarized as follows: 1. The path, velocity and acceleration of discharge arm were computer analyzed by vector analysis. Using results of the analysis and intrinsic constraints of the binder, discharge mechanism was modified to reduce the impact force on bundle by discharge arm in the range where the discharge performance was not deteriorated. This modification of the discharge mechanism could be done with an aid of four-bar linkage synthesis technique. As a result, average velocity and acceleration of the discharge arm during the discharge process were reduced respectively by 19 percent and 33 percent for binder A, and 17 percent and 35 percent for binder B. 2. Through the modification of the discharge mechanism, discharge losses of binder A were reduced by 42-56 percent for Milyang 23, Poongsan and Hangang chal, and discharge losses of binder B were reduced by 13-20 percent for Milyang 23 and Poongsan. 3. Discharge losses were decreased as the bundle size became larger and the size effect on the decrease rate appeared more significant in the binders with modifications than in those without modifications.

• Journal of Electrical Engineering and Technology
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• 제11권1호
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• pp.192-199
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• 2016

With changes in insulated defects, the environment, and so on, new partial discharge (PD) data are highly different from the original samples. It leads to a decrease in on-line recognition rate. The UHF signal and pulse current signal of four kinds of typical artificial defect models in gas insulated switchgear (GIS) are obtained simultaneously by experiment. The relationship map of ultra-high frequency (UHF) cumulative energy and its corresponding apparent discharge of four kinds of typical artificial defect models are plotted. UHF cumulative energy and its corresponding apparent discharge are used as inputs. The support vector machine (SVM) incremental method is constructed. Examples show that the PD SVM incremental method based on simulated annealing (SA) effectively speeds up the data update rate and improves the adaptability of the classifier compared with the original method, in that the total sample is constituted by the old and new data. The PD SVM incremental method is a better pattern recognition technology for PD on-line monitoring.

• 한국환경과학회지
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• 제21권4호
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• pp.479-488
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• 2012

A Dielectric barrier discharge (DBD) plasma is shown in the present investigation to be effective of phenol degradation in the aqueous solutions in batch reactor with continuous air bubbling. Removal of phenol and effects of various parameters on the removal efficiency in the aqueous solution with high-voltage streamer discharge plasma are studied. The effect of 1st voltage (80 ~ 220 V), air flow rate (3 ~ 7 L/min), pH (3 ~ 11), electric conductivity of solution (4.16 ${\mu}S$/cm, deionized water) ~ 16.57 mS/cm (addition of NaCl 10 g/L) and initial phenol concentration (2.5 ~ 20.0 mg/L) were investigated. The observed results showed that phenol degradation was higher in the basic solution than that of the acidic. The optimum values on the 1st voltage and air flow rate for phenol degradation were 140 V and 6 L/min, respectively. It was considered that absorbance variation of $UV_{254}$ of phenol solution can be use as an indirect indicator of change of the non-biodegradable organic compounds within the treated phenol solution. Electric conductivity was not influenced the phenol degradation. To obtain the removal efficiency of phenol and COD of phenol over 97 % (initial phenol concentration, 10.0 mg/L), 80 min and 120 min were need, respectively. Phenol and COD degradation showed a pseudo-first order kinetics.

• 한국환경과학회지
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• 제22권7호
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• pp.915-923
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• 2013

Decomposition of non-biodegradable contaminants such as phenol contained in water was investigated using a dielectric barrier discharge (DBD) plasma reactor in the aqueous solutions with continuous oxygen bubbling. Effects of various parameters on the removal of phenol in aqueous solution with high-voltage streamer discharge plasma are studied. In order to choose plasma gas, gas of three types (argon, air, oxygen) were investigated. After the selection of gas, effects of 1st voltage (80 ~ 220 V), oxygen flow rate (2 ~ 7 L/min), pH (3 ~ 11), and initial phenol concentration (12.5 ~ 100.0 mg/L) on phenol degradation and change of $UV_{254}$ absorbance were investigated. Absorbance of $UV_{254}$ can be used as an indirect indicator of phenol degradation and the generation and disappearance of the non-biodegradable organic compounds. Removal of phenol and COD were found to follow pseudo first-order kinetics. The removal rate constants for phenol and COD of phenol were $5.204{\times}10^{-1}min^{-1}$ and $3.26{\times}10^{-2}min^{-1}$, respectively.

• 한국표면공학회지
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• 제56권6호
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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.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권3호
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• pp.77-80
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• 2003

An innovative ozonizer has been developed using a high frequency, surface discharge and a high purity Ti-Si-AI ceramic catalyst as a dielectric component. Using a type of thin film, a thin cylindrical compound ceramic catalyst layer was adhered to the outside surface of its inner electrode. An alternating current (AC) exciting voltage with frequencies from 0.6 KHz to 1.0 KHz and peak-to-peak voltages of 4-6 ㎸ was applied between the electrodes to produce a stable high-frequency silent discharge. A substantial reduction of the exciting voltage was also enabled by means of a thin Ti-Si-Al ceramic catalyst tube. As a result, the ozonizer can effortlessly obtain the required ozone concentration (50-60 g/$m^2$ for oxygen) and high ozone efficiency consumption power (180 g/kWh for oxygen) with-out the assistance of any particular methods. For purposes of this experiment, oxygen gas temperature was set at 2$0^{\circ}C$, with an inner reactor pressure of 1.6 atm at 600 Hz and a flow rate of 2 l/min.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.208-211
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• 2003

The dielectric carbon nitride thin films were deposited onto Si(100) using a pulsed laser ablation of pure graphite target combined with a high voltage discharge plasma in nitrogen gas atmosphere. We can be calculated dielectric constant, ${\varepsilon}_s$, with a capacitance Sobering bridge method. We reported to investigate the influence of the laser ablation of graphite target and DC high voltage source for the plasma. The properties of the deposited carbon nitride thin films were influenced by the high voltage source during the film growth. Deposition rate of carbon nitride films were found to increase drastically with the increase of high voltage source. Infrared absorption clearly shows the existence of C=N bonds and $C{\equiv}N$ bonds. The carbon nitride thin films were observed crystalline phase, as confirmed by x-ray diffraction data.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1038-1041
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• 2003

In the paper, we investigated silicon surface microstructures formed by reactive ion etching in hollow cathode system. Wet anisotropic chemical etching technique use to form random pyramidal structure on <100> silicon wafers usually is not effective in texturing of low-cost multicrystalline silicon wafers because of random orientation nature, but High density hollow cathode plasma system illustrates high deposition rate, better film crystal structure, improved etching characteristics. The etched silicon surface is covered by columnar microstructures with diameters form 50 to 100nm and depth of about 500nm. We used $SF_{6}$ and $O_{2}$ gases in HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}$ $cm^{-3}$ at a discharge current of 20 mA. Silicon etch rate of 1.3 ${\mu}s/min$. was achieved with $SF_{6}/O_{2}$ plasma conditions of total gas pressure=50 mTorr, gas flow rate=40 sccm, and rf power=200 W. Our experimental results can be used in various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this paper we directed our study to the silicon etching properties such as high etching rate, large area uniformity, low power with the high density plasma.