• Analytical Science and Technology
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• v.11 no.3
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• pp.229-230
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• 1998

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2005.12a
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• pp.130-130
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• 2005

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.575-581
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• 2012

The electrochemical oxygen demand (ECOD) is an additional sum parameter, which has not yet found the attention it deserves. It is defined as the oxygen equivalent of the charge consumed during an electrochemical oxidation of the solution. Only one company has yet developed an instrument to determine the ECOD. This instrument uses $PbO_2$-electrodes for the oxidation and has been successfully implemented in an automatic on-line monitor. A general problem of the ECOD determination is the high overpotential of electrochemical oxidations of most organic compounds at conventional electrodes. Here we present a new approach for the ECOD determination, which is based on the use of a solid composite electrodes with highly efficient electro-catalysts for the oxidation of a broad spectrum of different organic compounds. Lead dioxide as an anode material has found commercial application in processes such as the manufacture of sodium per chlorate and chromium regeneration where adsorbed hydroxyl radicals from the electro-oxidation of water are believed to serve as the oxidizing agent. The ECOD sensors based on the Au/$PbO_2$ electrode were operated at an optimized applied potential, +1.6 V vs. Ag/AgCl/sat. KCl, in 0.01 M $Na_2SO_4$ solution, and reduced the effect of interference ($Cl^-$ and $Fe^{2-}$) and an expended lifetime (more than 6 months). The ECOD sensors were installed in on-line auto-analyzers, and used to analyze real samples.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.1
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• pp.96-102
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• 2009

The effect of ultrasonic and alkaline pre-treatments on waste activated sludge (WAS) disintegration was investigated for improved anaerobic digestion. As WAS was treated by either methods, longer capillary suction time (CST) was required due to the break-up of cell walls, and its supernatant demonstrated increase in soluble chemical oxygen demand (SCOD), protein content and turbidity. Ultrasonic process combined with alkaline pre-treatment demonstrated higher SCOD and protein content in the supernatant as compared with ultrasonic pre-treatment only. However, the degree of disintegration (DDCOD) of WAS decreased with increasing solid concentration as both WAS disintegration methods employed simultaneously.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.335-338
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• 2009

The process of charging an oxidizer in the liquid propellant rocket can divide into the cooling of the oxidizer tank, the high flow charge, the small flow charge, and the replenishment charge for the correction of temperature. The oxidizer of the Naro(KSLV-I) first stage uses the liquid oxygen. And the flow rate and the temperature specification corresponding to each charge mode are presented for the requirement. The flow throttling valve and heat exchanger are installed in the oxidizer filling system in order to satisfy this kind of the flow rate and temperature requirement specification. In this research, by using the Flowmaster which is a commercial one-dimension thermo-fluidic analysis program, one dimensional flow system analyses was performed to predict the exact flow rate at each specific mode. Also, the flow rate correction sensitivity of the flow control valves was analytically determined to satisfy the flow condition refinement at each mode within the limited certification test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.781-783
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• 2011

The oxidizer filling system, ground facility of the launch complex, should accept difficult requirements from the launcher sufficiently. The launcher do not have unnecessary insulators for mass reduction and manages liquid oxygen mass fastidiously to satisfy the mission requirement. So, the ground facility should be able to accept its requirements, then we should make the operating process being adjusted. In this paper, the operating process design and verification results on the oxidizer filling ground facility for liquid rocket is demonstrated.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.341-341
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• 1994

생체막의 주요 구성성분인 인지질의 2번 위치에 결합한 불포화지방산은 각종 전이금속이나 각종 활성산소들의 공격을 쉽게 받아 지질과산화반응이 일어나서 생체에 유독한 화합물을 생성하게 된다. 생체는 이러한 기구의 해독을 위하여 크게 2가지 방어기전을 갖고 있다. 즉 Vitamin- C, $\alpha$-tocopherol, flavonoid, SOD, catalase 등과 같이 생성된 활성산소를 제거시키는 기구와. 활성산소에 의해 생성된 과산화물을 제거시키는 기구로 glutathione peroxidase (GPX)가 알려졌으며 GPX에 의해 독성이 낮은 수산화물까지 환원시키는 기구가 보고되었다. 그러나 인지질의 과산화물 그대로는 GPX의 기질이 쥘수 없으므로, 산화된 지방산을 절단하는 효소에 대한 기구의 해석이 요구되고 있다. 최근 여러질병에 관련되어 있는 인지질 2번위치의 지방산을 분해하는 phospholipase $A_2$ (PLA$_2$)가 과산화지질의 분해에 관여한다는 주장이 제기되었다. 따라서 본 연구에서는 rat liver microsome에 $CCl_4$투여로 일어나는 과산화반응에 있어서 PLA$_2$의 역할을 규명하기 위하여 본 실험을 행하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.477-477
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• 2010

태양전지용 TCO(Transfer Conductivity Oxide)는 가시광선 영역에서 높은 광 투과도(optical transmittance), 낮은 저항(resistivity), 우수한 박막 표면 거칠기(roughness) 등의 특성이 요구된다. 현재 가장 많이 사용되는 투명전극은 ITO(Indium Tin Oxide)가 보편적이다. 하지만 ITO에 사용되는 원료 재료인 In이 상대적으로 열적 안정성이 낮아 제조과정에서 필수적으로 수반되는 열처리가 제한적이며, 높은 원료 단가로 인하여 경제적인 측면에서 약점으로 지적되고 있다. 이러한 ITO 투명전극의 대체 재료로서 최근 ZnO 박막의 연구가 활발히 이루어지고 있다. MOCVD(Metal-Organic chemical vapor deposition)로 Soda lime glass 기판위에 약 900nm의 두께로 증착한 BZO(Boron-zinc-oxide)박막을 수소 플라즈마 처리공정을 한 뒤 산소 플라즈마를 이용하여 재처리 하였다. 산소 플라즈마 처리 공정은 RIE(Reactive Ion Etching)방식의 플라즈마 처리 장치를 사용하였고 공정 조건은 13.56 MHz의 RF주파수를 사용하여 RF 전력, 압력, 기판 온도 등을 변화시켜 BZO 박막의 전기적 특성을 측정 및 분석하였다.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.373-384
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• 2011

The objective of this was to determine how the seasonal intensive rainfall influenced the water quality, and to analyze the long-term temporal trend of water chemistry and spatial heterogeneity in the upstream watershed of Southern Han River using water quality dataset from 1997 to 2007. The largest seasonal variability in most parameters occurred during the two month July and August and there were closely associated with a large spate of summer monsoon rain. Total phosphorus (TP), chemical oxygen demand (COD), and suspended solids (SS) were greater during summer than any other seasons, and had a direct correlation with precipitation (r>0.4, p<0.01, n-120). In addition, dissolved oxygen (DO) had and inverse function with precipitation (r=-0.542, p<0.01). Overall, the data of total phosphorus (TP) and suspended solids (SS) showed that water quality was worst in Site I1, compared to the others. This was due to continuous effluents from the highlands' fields and cattle farms within the upstream area of Doam lake (Song stream). Based on the overall dataset, an efficient water quality management is required in the highlands and farms areas for better water quality with precipitation (r.0.4, p<0.01, n=120).

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.14 no.2
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• pp.80-89
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• 2009

The rates of sediment oxygen demand(SOD) and denitrification(DNF) were measured using $^{15}N$ isotope pairing technique in intact sediment cores in the shelf of Dok Island. The SOD and DNF in the continental shelf of Dok Island were ranged from 1.04 to $9.08\;mmol\;m^{-2}\;d^{-1}$ and from 7.06 to $37.67\;{\mu}mol\;m^{-2}\;d^{-1}$, respectively. The SOD and DNF values in this study are higher than typical deep sea sediment. The SOD and DNF in this study were high in the high organic matter content sediment and high organic matter content was promotive of coupled nitrification-denitrification. Organic carbon contents in surface sediment ranged from 1.8 to 2.4%, which is higher than typical deep sea sediments. Therefore we conclude that the organic matter content in surface sediment is determined by the nature of the export production not the water depth in East sea sediment and the nature of the export production also determines remineralization processes such as SOD and DNF in East sea/Ulleung Basin sediment.