• Journal of fish pathology
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• v.25 no.1
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• pp.47-58
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• 2012

Behavioral and physiological responses of juvenile red seabream (Pagrus major) to different concentrations of ethanol were investigated. No swimming and no reaction to touching by a wooden stick was observed at 0.6% ethanol group in behavioral response, and survival rate was 100% after 5 hours of treatment. Red blood cell count, hematocrit and hemoglobin levels in plasma were not significantly different among all groups. AST activities in plasma significantly decreased as ethanol concentration increased. On the contrary, ALT activities in plasma significantly increased as ethanol concentration increased. Cortisol level in plasma was the lowest in 0.6% ethanol group. Glucose levels in plasma increased significantly when ethanol concentration increased more than 0.4%. Oxygen consumption of fish in 0.6% ethanol seawater was constantly lower than that of fish in control seawater from 2 hours after the exposure to ethanol seawater until the end of experiment.

• Applied Chemistry for Engineering
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• v.25 no.4
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• pp.386-391
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• 2014

Atmospheric-pressure nonthermal corona discharge plasma was applied to the sterilization of biologically contaminated scoria powder. Escherichia coli (E. coli) culture solution was uniformly sprayed throughout the scoria powder for artificial inoculation, which was well mixed to ensure uniformity of the batch. The effect of the key parameters such as discharge power, treatment time, type of gas and electrode distance on the sterilization efficiency was examined and discussed. The experimental results revealed that the plasma treatment was very effective for the sterilization of scoria powder; 5-min treatment at 15 W could sterilize more than 99.9% of E. coli inoculated into the scoria powder. Increasing the discharge power, treatment time or applied voltage led to an improvement in the sterilization efficiency. The effect of type of gas on the sterilization efficiency was in order of oxygen, synthetic air (20% oxygen) and nitrogen from high to low. The inactivation of E. coli under the influence of corona discharge plasma can be explained by cell membrane erosion or etching resulting from UV and reactive oxidizing species (oxygen radical, OH radical, ozone, etc.), and the destruction of E. coli cell membrane by the physical action of numerous corona streamers.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.120-120
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• 2003

MOCVD법으로 TiN 표면에 Ru을 증착함에 있어서 Ru의 핵생성을 고양시키기 위한 ECR plasma 전처리 세정이 필요하다. 본 연구에서는 Ru 증착시 ECR $H_2O$$_2$, AE Plasma 전처리 세정 효과를 SEM, AES, XRD로 분석하였다. Ru의 핵생성은 ECR H$_2$, Ar Plasma의 노출시간이 증가할수록 향상된 반면, ECR $O_2$ plasma의 경우 노출시간이 증가할수록 핵생성 효과는 감소하였다. H$_2$ plasma 내의 H$_2$ion은 Ti와 NH$_3$를 형성하기 위해서 TiN과 반응하여 TiN을 Ti로 개질 시켰으며, Ar plasma 전처리 세정하는 동안 Ar plasma 내의 Ar ion은 TiN 또는 TiON 표면의 질소와 산소원자를 제거하는 효과를 나타내었다. 그 결과 TiN 표면상에서도 Ru의 핵생성이 쉽게 이루어졌으며 H$_2$, Ar ECR Plasma 전처리 세정에서 RU 핵생성이 향상되는 결과를 얻었다. 세 종류의 plasma중에서 Ar ECR plasma로 전처리 세정한 경우에 가장 높은 Ru 핵생성 밀도를 얻을 수 있었다.

• Journal of Welding and Joining
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• v.12 no.1
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• pp.94-101
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• 1994

In this study, plasma spraying has been used to produce $TiO_2$ polycrystalline coatings from $TiO_2$ powders. The physical and chemical properties of plasma sprayed $TiO_2$ coatings depend greatly on plasma spraying conditions. The electrical resistivity, oxygen concentration, photocurrent and crystal structure of plasma sprayed $TiO_2$ coating has been studied. The results are as follows: 1. The oxygen loss and electrical conductivity of $TiO_2$ plasma sprayed coatings increased by low pressure and high amount of auxiliary gas, hydrogen in plasma spraying. 2. Oxygen loss increase electrical conductivity, and decrease photocurrent of $TiO_2$ plasma sprayed coatings. 3. Photocurrent of $TiO_2$ plasma sprayed coatings manufactured in atmospheric pressure is higher than that of low pressure.

• Journal of the Korean Magnetics Society
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• v.11 no.5
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• pp.196-201
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• 2001

The dependence of CoFe interfacial layer thickness and plasma oxidation condition on tunneling magnetoresistance (TMR) in Ta/NiFe/FeMn/NiFe/Al$_2$O$_3$/NiFe/Ta tunnel junctions was investigated. As the CoFe layer thickness increases, TMR ratio rapidly increases to 13.7 % and decreases with further increase of the CoFe layer thickness. The increase of TMR with the CoFe thickness up to 25 was thought to be due mails to the high spin-polarization of CoFe. The maximum MR of 15.3% was obtained in the Si(100)/Ta(50 )/NiFe(60 )/FeMn(250 )/NiFe(70 )/Al$_2$O$_3$/NiFe(150 )/Ta(50 ) magnetic tunnel junction with a 16 Al oxidized for 40 sec using a Ar/O$_2$ (1:4) mixture gas.

• Journal of the Korean Society of Safety
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• v.8 no.3
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• pp.83-90
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• 1993

직류 아아크 용접시 아아크 프라스마와 용융 금속 사이의 계면에서 일어나는 전기 화학 반응이 용착금속 내의 산소와 질소의 함량에 미치는 영향이 고찰되었다. 열 화학 반응 뿐만 아니라 전기 화학 반응도 용접부의 산소 및 질소의 함량을 결정하는 중요한 반응 메카니즘이라는 것과 전기 화학 반응의 양을 결정하는 것은 단위 면적당 통과하는 전류의 양을 조절하는 용접 전류와 용접 속도라는 것이 실험적으로 입증되었다. 따라서 이 연구 결과는 아아크 용접시 적당한 용접 조건의 선택뿐만 아니라 용접 재료의 설계 또는 선택에 중요한 지침을 준다.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.946-951
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• 2005

In this wort plasma treatment was evaluated as an alternative clean desizing technology. Size materials such as PVA(polyvinyl alcohol), PACL(polyacrylic acid esters) and their mixture on PET(polyethylene terephthalate) fabrics were treated by $N_2$ and $O_2$ plasma. $O_2$ plasma was more efficient in size removal than $N_2$ plasma, and the removal of PVA was higher than that of PACL. SEM(scanning emission microscopy) pictures of the plasma treated samples directly proved the disappearance of sizing agents. After $O_2$ plasma treatment, the PET fabrics were subjected to conventional desizing process. Compared with untreated fabrics, the desizing effluent from the treated fabrics gave lower TOC, COD and $BOD_5$ values. This indicates plasma treatment not only serves to directly remove sizing agents but also offered several advantages by changing the chemical properties of sizing agents. Lastly, the effect of plasma desizing process on dyeing was examined using color difference and dyeing fastness tests. The CCM(computer color matching) results showed rotor difference between PET fabric desized by $O_2$ plasma treatment for 20 min and reference PET fabric desized by the conventional wet desizing process was around 1. This suggests the treated PET fabric can be directly subjected to dyeing process without any additional process. The plasma treated fabric also gave a good result of dyeing fastness so that grades of laundering, crocking, heat and light fastness were same or even better than the reference PET fabric did.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.99.2-99.2
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• 2015

현재 투명전극(Transparent Conductive Oxide: TCO)은 평판 디스플레이, 태양전지, 터치패널, 투명 트렌지스터의 전극 등 여러 분야에서 연구되어지고 있으며, 주로 IT 산업의 핵심재료로 ITO (Indium Tin Oxide)가 사용되고 있다. ITO 박막은 주로 스퍼터 공정을 통해 제작이 되며, 전기전도도가 우수하며 높은 Optical Band Gap을 가지고 있어 투명전극으로 많이 사용되고 연구되어지고 있다. 산화물 박막을 증착할 때 산소유량에 따라 박막의 물성이 변하거나 박막의 특성이 저하되는 현상 등을 가지고 있어 공정시 산소유량이 중요한 변수로 작용하게 된다. 본 연구에서는 증착 공정 중 발생하는 플라즈마의 방출광을 가지고 산소의 대표적인 파장의 방출광을 관찰하여 방출광이 변화함에 따라 실시간으로 산소가스유량이 제어됨을 확인하였으며, 또한 산소유량제어를 통해 생성된 박막의 전기적 특성 및 광학적 특성 등 박막의 물성을 비교하였다.

• Journal of the Korean Institute of Gas
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• v.2 no.3
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• pp.60-69
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• 1998

Methane, the major constituent of natural gas, had been converted to higher hydrocarbons by microwave and radio-frequency plasma in vacuum condition. Methane had been activated to plasma by suppling high energy then converted to ethane, ethylene, acetylene. The direct conversion process of methane had produced few by-products and demanded low-energy. The plasma sources were microwave and radio-frequency. Two types of reactor had been used to activate methane. One is common single tubular-type reactor and the other is series coil-type reactor which used for the first time in this study. To produce more C2 products, methane had been converted by a plasma and catalyst. The results of this study could be used to study mechanism of plasma reaction of methane, design the plant-scale reactor.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.495-504
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• 2015

This work investigated the characteristics of a packed-bed plasma reactor system and the performances of the plasma reactors connected in series or in parallel for the decomposition of ethylene. Before the discharge ignition, the effective capacitance of the ${\gamma}$-alumina packed-bed plasma reactor was larger than that of the reactor without any packing, but after the ignition the effective capacitance was similar to each other, regardless of the packing. The energy of electrons created by plasma depends mainly on the electric field intensity, and was not significantly affected by the gas composition in the range of 0~20% (v/v) oxygen (nitrogen : 80~100% (v/v)). Among the various reactive species generated by plasma, ground-state atomic oxygen and ozone are understood to be primarily involved in oxidation reactions, and as the electric field intensity increases, the amount of ground-state atomic oxygen relatively decreases while that of nitrogen atom increases. Even though there are many parameters affecting the performance of the plasma reactor such as a voltage, discharge power, gas flow rate and residence time, all parameters can be integrated into a single parameter, namely, specific input energy (SIE). It was experimentally confirmed that the performances of the plasma reactors connected in series or in parallel could be treated as a function of SIE alone, which simplifies the scale-up design procedure. Besides, the ethylene decomposition results can be predicted by the calculation using the rate constant expressed as a function of SIE.