• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.362-368
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• 2005

The pH, alkalinity and calcium hardness could be adjusted by $CO_2$, $Ca(OH)_2$, and $Na_2CO_3$ addition in the water treatment process for corrosion protection of the water pipes. This research was performed to investigate the effect on the variation of water quality on the unit process by addition $CO_2$, $Ca(OH)_2$, and $Na_2CO_3$ in water treatment process. Carbon dioxide and lime were added before the coagulation basin and soda ash was added after the BAC process. pH and aklainity were increased at coagulation basin then after the water qualities had sustained similiarly to BAC process. There was no effect on turbidity and DOC removal efficiency during experimental period by addition\ $CO_2$, $Ca(OH)_2$, and $Na_2CO_3$ solution was added into clear well, the last process for optimum control of CCPP and is used mainly to control pH and alkalinity. In this research, average pH, alkalinity, and calcium hardness in treated water were 8.39, 61.4 mg/L as $CaCO_3$, 59.4 mg/L as $CaCO_3$, respectively and CCPP of treated water was higher than 29.5 mg/L to BAC process water, so adjusted water was expected to prevent internal corrosion of water pipe.

• KSBB Journal
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• v.17 no.2
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• pp.189-194
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• 2002

Laccase produced from Trametes sp. was immobilized on CNBr-activated Sepharose-4B (CAS4B) and tested for degradation of azo dyes. Laccase was efficiently immobilized on CAS4B. Immobilization of laccase on CAS4B increased pH, thermal and proteolytic stabilities. Optimum pH and temperature of immobilized laccase were pH 3 and 40$\^{C}$, respectively as same as those of free laccase. The K$\_$m/($\mu$mol/ml) values of free and immobilized laccase for Reactive Blue 19 as the substrate were 0.34 and 2.07, respectively V$\_$max/($\mu$mol/mL$.$min) values of them were 0.12 and 0.1, respectively. In repeated batch reactions, conditions retained high stability and degradation of dye for immobilized laccase were pH 5 and 30$\^{C}$. HBT didn\\`t decrease highly activity of immobilized laccase. Immobilized laccase was very stable for degrading dyes continuously in a packed-bed reactor containing laccase immobilized on CAS4B. For continuous degradation of 100 $\mu$M Reactive Blue 19 and 50 $\mu$M Acid Red 57 in the presence of 0.1 mM HBT under optimum conditions, immobilized laccase retained 70% of degradation ability even after 30 hours.

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.194-200
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• 2000

The amount of swine wastewater reaches about $197,000m^3$ per day at live-stock houses in the whole country. A half of the swine wastewater resources are too small to be restricted legally. This untreated wastewater causes the eutrophication in the water bodies. In case of swine wastewater treatment, the solid-liquid separation must be performed because feces(solid phase) and urine(liquid phase) have large differences in nitrogen and phosphorus concentration. It is necessary to assess exactly the concentration of the pollutants in swine wastewater for planning the wastewater treatment facilities. A full-scale operation was carried out in K city and the plant is consists of conventional plant, the supplementary flocculation basin of chemical treatment process and $anaerobic{\cdot}aerobic$ basin for nitrogen removal. The improved full-scale swine wastewater treatment plant removed the $1,500{\sim}3,000mg/l$ of total-nitrogen(T-N) to 120mg/l of T-N and $131{\sim}156mg/l$ of total-phosphorus(T-P) to $0.15{\sim}1.00mg/l$ of T-N. Accordingly, as a results of operational improvement, the removal efficiencies of T-N and T-P were over $92{\sim}96%$, 99%, respectively. The continuous supply of organic carbon sources and the state of pH played important roles for the harmonious metabolism in anaerobic basin and the pH value of anaerobic basin maintained at about 9.0 for the period of the study.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.229-229
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• 2004

원자력발전소에서 원자로 냉각재 중의 용존산소 제어는 원자로 냉각재 계통에서의 전면 부식과 다양한 형태의 응력부식균열(SCC)를 완화시키는데 기여한다. 원자로 냉각재 계통내에 용존 되어있는 산소는 발전소 기동 시에는 하이드라진($N_2H_4$)을 넣거나 인위적 배기를 통해 제거하고, 정상운전 중에는 체적제어탱크(VCT)에 수소를 가압하여 제거시킨다. 계통내로 유입되는 용존산소를 최대한 억제하기 위하여 대부분의 원자력발전소는 원자로 보충수 탱크 상층부에 질소를 주입하여 탱크로 유입되는 공기를 차단하고 있으나, 이 과정에서 일부 수중에 용해되어 들어가는 질소는 계통 내에서 NH$_3$를 형성하여 화학체적제어계통(CVCS)의 이온교환 수지탑에 치환됨으로서 기포화 되어있는 Li을 계통으로 빠져나오게 하여 계통 pH에 영향을 미친다.(중략)

• Proceedings of the Korea Contents Association Conference
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• 2011.05a
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• pp.333-334
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• 2011

연료전지 자동차 기술 분야에서 한국의 현대자동차가 243건으로 가장 많은 등록특허를 보유한 것으로 나타났으며, 일본의 HONDA MOTOR가 220건, TOYOTA MOTOR가 153건의 특허를 보유하고 있는 것으로 나타났다. 주요출원인별 IPC 분포를 통해 연구개발 역점분야를 살펴보면, 주요 상위 출원인은 전지(H01M), 전기장치 또는 추진장치의 배치(B60L), 동력 전달 장치의 배치(B60K) 분야에 연구개발이 집중되었으며, 현대자동차는 전지(H01M), 전기장치 또는 추진장치의 배치(B60L) 분야 이외에 운전제어시스템(B60W), 냉각(F01P) 분야의 연구가 다른 업체에 비해 활발한 것으로 나타났다.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.699-701
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• 2001

The expert system monitoring and diagnosing 765kV power apparatus was described in this paper. To develop this expert system, we studied the knowledge bases and data bases for 765kV transformer and GIS. In order to make the reliable inference of knowledge base and the good MMI(Man Machine Interface), the data bases were consisted of the tables of power apparatus information, limit level value, measured input data, inference result and diagnosis result. The knowledge base had various rules to infer the conditions of transformer and GIS. We applied both the forward chaining and backward chaining methods to these rules of system for good inferences. This paper describes the applied methods for expert system. Also, this developed system was tested with dissolved gas analyzing result and the result was shown.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1213-1214
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• 2006

본 논문에서는 5 kWh급 초전도 플라이휠 에너지 저장장치(Superconductor Flywheel Energy Storage System : SFES)를 제작하고 시험운전을 통하여 회전 테스트를 수행하였다. 본 연구에서 사용된 초전도 베어링은 저널형 베어링으로써 액체 질소를 순환시켜 초전도체를 냉각시키고 휠을 부양시켜서 전동발전기를 통하여 회전시키게 된다. 액체 질소를 순환하였을 경우 초전도 베어링의 냉각특성을 고찰하였고, 전동 발전기를 이용하여 2000[rpm]까지의 회전 테스트가 수행 되었으며, 전동발전기의 동작 특성 및 회전시 휠의 궤적과 축진동 특성을 테스트 하였다.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.156-158
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• 1998

This paper presents parallel operation of two 3-phase PWM converters whose Power and control schemes can be directly applied to a large capacity system. This paper describes power circuit, dc voltage regulation, input power factor correction and balancing load control of two converters. Switching device Is IGBT and CPU of control is 32-bit floating point DSP for real time instantaneous control. Simulations and experimental results for 20kw model conform the validity of proposed schemes.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.2
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• pp.103-116
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• 2006

By executing corrosion experiment on Inconel 600, 690 used to material of S/G tube in domestic NPP, this paper show estimation of amount of product such as Co-58, Co-60, Cr-51, Mn-54, Fe-59 which are main exposure cause to the workers in NPP. Therefore, Making the 12 samples consisted of Inconel 600, 690, whole corrosion experiment was carried out for 60 days(each pH by 20 days). The conditions of those tests were similar or more harsh than actual conditions of domestic NPP. The Glow Discharge Spectrometer(GDS) was used for quantitative analysis of results. The results of using GDS, the Inconel 600 corrodes more than Inconel 690 at pH 7 and pH 9. However, it is observed that Inconel 690 corrodes more than Inconel 600 at pH 4. Those results is estimated that test sections had the effect of transient. The long terms of experiment is required to minimize and solve the problem.

• Journal of Korea Soil Environment Society
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• v.4 no.1
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• pp.85-96
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• 1999

Biofiltration is an attractive technique for elimination of VOCs and odorous compounds from low-concentration, high-volume waste gas streams because of its simplicity and cost-effectiveness. The objective of this study was to estimate the removal characteristics of Odorous Compounds including $H_2$S, $NH_3$End BTEX in MSW landfill gases. This Study was conducted at Nanjido landfill site. A compost from the Nanjido composting facility was used as a filling material for biofiltration. Extracted landfill gases were injected into biofilter reactors after mixing with air. Experiments were performed in an incubator being set to $20^{\circ}C$ $H_2$S concentrations were monitored at the depths of 25, 50, 75 and 100cm from the bottom Of the biofilter reactors. 98% of $H_2$S was removed at the filling depth of only 25cm. NH$_3$removal rate was about 85%. Toluene removal rate was the highest among BTEX. Significant pH drop of a filling material was not observed during the biofilter operation of 1 month. Without mixing the landfill gas stream with all, the removal rate of $H_2$S decreased down to 30%.