• The Journal of Engineering Geology
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• v.23 no.1
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• pp.29-36
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• 2013

The application of appropriate rehabilitation methods can improve the efficiency of clogged wells and extend their life. In this paper, we study the feasibility of well cleaning using high-voltage pulsed discharge, in which electrical energy is used to produce impulsive pressure in water, in contrast to conventional methods that employ chemical or pneumatic energy sources. This technique utilizes the compressive shock wave generated by the expansive force of hot, dense plasma that is produced during a pulsed discharge in the gap between electrodes immersed in water. Compared with conventional techniques, this method is simple, and easy to handle and control. Using a capacitive pulsed power system with an electrical energy of 200 J, an impulsive pressure of 10.7 MPa is achieved at the position 6 cm away from the discharge gap. The amplitude of the impulsive pressure was easily controlled by adjusting the charging voltage of the capacitor and was almost linearly proportional to peak discharge current. The technique achieved good results in cleaning feasibility tests with mock-up specimens similar to clogged well screens.

• Analytical Science and Technology
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• v.15 no.6
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• pp.514-520
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• 2002

The electrothermal vaporization (ETV) hollow cathode glow discharge atomic emission spectrometer for analysis of liquid sample has been developed and characterized. This system has improved the sample introduction method of electrothermal vaporization and the hollow cathode glow discharge. The sample introduction method was possible to provide high analyte transport efficiency to the plasma by helix coil made of tungsten material. In addition, small volume samples (<$30{\mu}{\ell}$) could be used. The system has glow discharge cell with special design for improvement of precision. The effect of discharge parameters such as discharge power, gas flow rate has been studied to find optimum condition. The emitted light was effectively carried into detector by fiber optic cable in UV region. The calibration curve of Pb, Cd were obtained with 3 samples.

• Journal of Hydrogen and New Energy
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• v.9 no.2
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• pp.77-84
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• 1998

Hydrogen isotope exchange in mixtures of $H_2O/D_2$, $H_2O/D_2O$, or $D_2O/H_2$ can be facilitated under electrical discharge. For example, a simple DC corona discharge through the mixture creates a plasma in which the reactants are excited energetically. The reactants in such plasma, due to increase in population of excited quantum levels or due to production of radicals or ions, undergo very rapid chemical reactions even at ambient temperature. The isotope exchange reaction of hydrogen(H) and deuterium(D) produces the third kind of heavy water(HDO) and isotopic hydrogen gas(HD), as shown in $D_2+H_2O{\rightarrow}HD$ K=11.257(at $25^{\circ}C$) The reaction products can be detected with temporal resolution using the Fourier transform infrared(FTIR) absorption spectroscopy. Since $H_2O$, $D_2O$ and HDO are all infrared active with different absorption peaks, FTIR proves to be a useful tool for monitoring the reaction. Experimental results show that the electrical method is indeed a useful means to promote the reaction, showing a better efficiency than traditional catalytic methods.

• Proceedings of the Safety Management and Science Conference
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• 1999.11a
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• pp.543-563
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• 1999

For hazardous air pollutants(HAP) such as NO and $NO_2$ decomposition efficiency, power consumption, and applied voltage were investigated by SPCP(surface induced discharge plasma chemical processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of HAP with various electric frequencies(5~50 kHz), flow rates(100~1,000 mL/min) initial concentrations(100~1,000 ppm), electrode materials(W, Cu, Al), electrode thickness(1, 2, 3 mm) and number of electrode windings(7, 9, 11) were measured. Experimental results showed that for the frequency of 10 kHz, the highest decomposition efficiency of 94.3% for NO and 84.7% for $NO_2$ were observed at the poser consumptions of 19.8 and 29W respectively and that decomposition efficiency decreased with increasing frequency above 20 kHz. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. Decomposition efficiency was increased with increasing thickness of discharge electrode and the highest decomposition efficiency was obtained for the electrode diameter of 3mm in this experiment. As the electrode material, decomposition efficiency was in order : tungsten(W), copper(Cu), aluminum(Al).

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.133-138
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• 2000

MgO thin films were deposited using $Mg(tmhd)_2$ as a precursor dissolved in a solvent by electrostatic spray pyrolysis. When a pure tetra hydro furan was used as a solvent, a large number of particles appeared on the MgO thin film surface due to homogeneous nucleation. However, by adding 1-butyl alcohol or 1-octyl alcohol to THF, homogeneous nucleation was restricted and the number density of the large particles was also drastically reduced. X-ray diffraction analysis showed that the MgO films had a (100) preferred orientation regardless of the type of solvents used. Characterization using Fourier Transformed-Infrared and spectroscopic photometer revealed that the crystallized MgO thin films on the glass substrate had a high optical transmittance (> 85 %) in the visible range. Discharge characteristics of MgO thin films deposited by ESP method on an alternating-current plasma display panel were compared with a MgO thin film prepared by reactive radio-frequency planar magnetron sputtering.

• Journal of the Korean Vacuum Society
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• v.2 no.3
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• pp.346-354
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• 1993

The diamond particles and films were deposited on Si and qurtz substrate for $CH_4-H_2$ mixed gas by using RF plasma CVD. The temperature of substrate and the thinkness of films deposited on Si substrate were uniformly kept up by inserting metal plate between substrate and substrate holder. On increasing the reaction pressure in the same discharge power, the morphologies of films were changed from well-defind films to micro-crystal or ball-like. When diamond films were deposited on Si substrate from $CH_4-H_2$ mixed gas, we obtained well-defined diamond films at lower concentration than 0.5 vol% of $CH_4/H_2$. The deposited diamond films were indentified by SEM, XRD and Raman spectroscopy.

• Journal of the Korean Society of Safety
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• v.17 no.3
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• pp.112-117
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• 2002

A comparative investigation of an experimental and a simulation of chemical kinetics for NOx removal from silent(dielectric-barrier) discharges is presented. Several types of dielectric-barrier discharges were implemented depending upon the configuration of electrodes. The simulation was based on an approximate mathematical model for plasma cleaning of waste gas. The influence of non-uniform distributions of species due to the production of primary active particles in the streamer channel was taken into account. A comparison of observed experimental to the calculated removal efficiency of NOx showed acceptable agreement.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.34-34
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• 2012

Polypropylene 섬유는 세계적으로 큰 관심을 모으고 있는 섬유 소재로 환경친화성, 경량성, 신축성 등 다양한 기능성을 보유하여 미국, 일본 등의 선진국에서 의류 및 인테리어용으로 채택하여 널리 사용되고 있다. 그러나, polypropylene 섬유는 다른 섬유에 비해 융점이 매우 낮아 내열성이 약하여 가공 공정시 고온을 피해야 하고, 곁가지가 거의 없고 섬유 분자 구조가 매우 조밀하며 탄소와 수소로만 이루어진 분자구조에 의한 극소수성 성질 때문에 다른 종류의 물질들과 접착력이 없어 사용에 제약을 주어 다양한 용도로의 활용이 제한되고 있는 실정이다. 본 연구에서는 Polypropylene 섬유의 제품화에 필요한 요소 기술의 기초를 마련하고자 대기압 플라즈마를 적용하여 소수성 표면을 지니는 표면을 친수화 함으로써 polypropylene 섬유에 후가공이 가능하도록 한다. 따라서 Plasma 표면 처리에 의해 polypropylene 섬유에 미치는 영향에 대하여 조사하고, 표면을 친수화 함으로써 습윤성, 접착성 등 다양한 가공 기술을 적용하여 PP 섬유의 기능성을 향상시키고자 한다. 플라즈마 처리에 의한 폴리프로필렌 섬유의 모폴로지 변화는 주사전자현미경 (FE-SEM)으로 확인하였으며 표면개질 효과는 Wicking Test로 평가하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.183-187
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• 1997

The Thin films were obtained by plasma polymerization of phenyl isothiocyanate. Polymerizations were carried out in rf(13.56 [MHz]) glow discharge generated in an inter-electrode capacitively coupled gas flow system. It was fecund that this monomer produces uniform films with a wide range of thicknesses, from hundreds of nanometers to tens of micrometers. The deposition rate appeared to be dependent on the substrate distance from the monomer inlet. The IR data revealed significant decrease in -NCS groups content in the polymer as compared with the monomer spectrum and indicated for the appearance of new absorption bands corresponding to the -CN and C-H aliphatic groups. The soluble fraction by GC was found to be composed of numerous low molecular-weight compounds.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1427-1434
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• 2014

Among the medical devices, medical treatments inflicting physical energy from the outside of the body to the inside or using the energy from the devices which take advantages of chemical changes of the human body require a high degree of reliability and safety. In particular, the medical treatment on the most exposed skin to the external surface in all parts of the human body will be very important. In this perspective, when you undergo skin treatment, you need to reduce all risks and to maximize the effect of treatment equipment. Therefore, the development of equipment which guarantees high therapeutic efficacy and safety is essential.