• Journal of Korean Society of Water and Wastewater
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• v.34 no.6
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• pp.393-402
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• 2020

In the membrane process, it is important to improve water treatment efficiency to ensure water quality and minimize membrane fouling. In this study, a pilot study of membrane process using reservoir water was conducted for a long time to secure high flux operation technology capable of responding to influent turbidity changes. The raw water and DAF(Dissolved Air Flotation) treated water were used for influent water of membrane to analyze the effect of water quality on the TMP (Trans Membrane Pressure) and to optimize the membrane operation. When the membrane flux were operated at 70 LMH and 80 LMH under stable water quality conditions with an inlet turbidity of 10 NTU or less, the TMP increase rates were 0.28 and 0.24 kPa/d, respectively, with minor difference. When the membrane with high flux of 80 LMH was operated for a long time under inlet turbidity of 10 NTU or more, the TMP increase rate showed the maximum of 43.5 kPa/d. However, when the CEB(Chemically Enhanced Backwash) cycle was changed from 7 to 1 day, it was confirmed that the TMP increase rate was stable to 0.23 kPa/d. As a result of applying pre-treatment process(DAF) on unstability water quality conditions, it was confirmed that the TMP rise rates differed by 0.17 and 0.64 kPa/d according to the optimization of the coagulant injection. When combined with coagulation pretreatment, it was thought that the balance with the membrane process was more important than the emphasis on efficiency of the pretreatment process. It was considered that stable TMP can be maintained by optimizing the cleaning conditions when the stable or unstable water quality even in the high flux operation on membrane process.

• The Korean Journal of Ecology
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• v.19 no.5
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• pp.477-486
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• 1996

The freshwater goby, Micropercops swinhonis ($G\"{u}nther$) was studied on the spawning behavior and egg develeopment at the two areas of Chollabukdo, Korea from March to May 1995. Egg mass attached to a layer under stones and the inner wall of waterplant, Cyperus. Spawning behavior was divided in to 1) premating stage: selecting spawning sites and formation of territory by male, 2) mating stage: enticement with zigzag-like dance and intermittant shaking of head by male and fertilization, 3) postmating stage: fanning, guarding and cleaning the nest by male. The eggs were transparent and spherical in shape, measuring $0.9\times1.4mm$ with yellowish yolk sac and many oil globules. Hatching began in about ten days after fertilization at water temperature $16~20^{\circ}C$. The newly hatched larvae were 3.8~4.0 mm in total length with 30 myomeres and their mouths and anuses were opened. Melanophores appeared at the air-bladder and the ventral side of caudal region.gion.

• Environmental Analysis Health and Toxicology
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• v.15 no.1_2
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• pp.39-43
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• 2000

Linear alkyl sulfonates (LAS) constitute a large fraction of the surfactants used in cleaning processes in households, trade and industry Despite the industrial significance and the possible environmental impact of these compounds, the fast and inexpensive determination of LAS concentrations is still a difficult task. In this study, near infrared (NIR) spectroscopy which is a rapid spectroscopic analysis method compared with a traditional analytical method for the measurement of LAS concentration such as HPLC, GC and standard wet chemistry method. NIR spectra of LAS between 0.313 and 25.0% (w/v) in water were utilized to develop a calibration model. The best results (R ＝ 0.998, SEP ＝ 0.244% (w/v)) obtained by using partial least-squares regression with spectral data treatment and 2nd derivatization were comparable to the results (SEC ＝ 0.186% (w/v), SEP ＝ 0.206% (w/v)) obtained by using multiple linear least-squares regression (MLR). However, models based on derivative spectra have no significant advantage with MLR.

• Journal of Magnetics
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• v.18 no.3
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• pp.365-369
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• 2013

Coal ash is known to contain a noticeable amount of valuable elements, including transition metals and lanthanides. Therefore it is quite actual problem to extract them for metallurgy and other applications. This paper presents the results of high gradient magnetic and mechanical separation, microscopy, element analyses and optical spectroscopy of brown coal ash taken from the combustion camera and chimney-stalk of Angren thermal power station. The separated magnetic fraction was 3.4 wt.%, where the content of Fe in ferrospheres increased to 58 wt.%. The highest contents of Fe and rare earth elements were found in the fine fractions of $50-100{\mu}m$. Optical absorption spectroscopy of water solutions of the magnetic fractions revealed $Fe^{2+}$ and $Fe^{3+}$ ions in the ratio of ~1:1. The separated coal ash could be used for cleaning of technological liquid waste by means of the high gradient magnetic field.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.139-147
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• 2019

Incorporation of CuO nanoparticles during the polymerization of aniline in the presence of ammonium peroxydisulphate as an oxidizing agent and sodium salt of dodecylbenzene sulphonic acid as dopant as well as surfactant yielded water soluble CuO-PANI composite. Comparison of recorded spectra like FTIR, XRD and SEM with reported one confirm the formation of the composite. Analysis by gravimetric method exposes that the synthesized composite is having resistivity against corrosion, with slight variation in efficiency on extending the time duration up to eight hours in strong acidic condition. OCP measurement, potentiodynamic polarization and EIS studies also confirms the suppression ability of composite against corrosion. Riskless working environment could be provided by the synthesized composite during industrial cleaning process.

• 연구논문집
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• s.23
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• pp.93-107
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• 1993

The chemistry and performance characteristics of the EBDS process have been introduced, in which experimental results from laboratory, test plant, and pilot plant studies agree very well and can be understood from detailed kinetic models. The parametric dependencies of the NOx and $SO_2$, removal yields on the input conditions have been discussed and formulated quantitatively. The process is best suited for flue gas with high $SO_2$, loadings. The operation conditions, such as dose, ammonia, and water additions, can be adjusted fast upon load changes. The process works waste water free and the major product is a mixture of ammonium nitrate and sulfate that can be used as fertilizer. The up-date results show that the EBDS technology is safe and competitive with other already well-established technologies. Due to these interesting features, the electron beam process has gained much international recognition. Demonstration units of 100MW have been proposed in the United States and Japan. Further pilot plants are under construction in Poland and China, countries that make abundant use of highsulfur coal. Additional research activities are under way to further improve the energy efficiency of process, and accelerator prices have been decreasing during the past 10 years. So the EBDS process has a good chance to start a new generation of emission-control technology.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.415-418
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• 2008

This paper presents an innovative prototype of a new conceptual electromagnetic induction-based fluid beating appliance using voltage-fed type scries capacitor-compensated load resonant high-frequency IGBT inverter with a phase-shifted PWM and a power factor correction schemes. Its operating characteristics in steady-state are illustrated including unique features and evaluated on the basis of its computer simulation and experimental results of 10kw breadboard appliance for hot water producer and superheated steamer. The promising cost effective inverter-fed boiler appliances for electromagnetic induction-heated type fluid-heating in the pipeline systems are proposed for induction-heated boiler, super heat steamer, high temperature water producer, hot gas producer and metal catalyst heating for exhaust gas cleaning in engine, which are more suitable and acceptable for industrial, chemical, and consumer energy utilization for household and business from a practical point of view.

• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.159-168
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• 2002

A lab-scale Reverse Osmosis(RO) membrane reactor was installed to investigate the membrane permeability, characteristics of membrane fouling at each conditions, and performance of elimination at different trans-membrane pressure(TMP) in the liquid fertilizer accumulated system. Experimental setup was divided to three different TMP conditions. As a result of experiment, permeability of RO membrane was proportional to the increase of TMP and temperature. After experiment was completed, two types chemical cleaning(remove the organic foulant and inorganic foulant) was done, and recover rate of permeability was each 99.8, 99.7 and 99.7%, respectively. From this experimental data, membrane fouling could be determined that the most of it was recoverable in this system, and major reason of fouling was concentration polarization. Elimination rate of solute substance in the liquid fertilizer indicated very stable(above 99%), except ammonia nitrogen, and the most stable elimination rate was investigated at the highest TMP condition (Run 3).

• Journal of Conservation Science
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• v.16 s.16
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• pp.39-51
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• 2004

The standing Buddha named Taehwa 4 yew in the Jincheon were sculptured with rock cliff of the dark grey shale. Front of the Buddha statue shows $N40^{\circ}W$ strike with nearly vertical dip toward the back side. Rock blocks of the Buddha statue well developed with bedding and laminations whereas rock surface distributed into the various irregular discontinuities. Sculptured lines of the Buddha were uncertain because of degradation and exfoliations on the rock surface. The surface near the Buddha statue is highly contaminated with lichen and mosses, and accelerate physical and biological weathering owing to the roots of weed and bush along the fracture systems. For the conservational treatment, we treated with primary wet cleaning by air gun and secondary cleaning treatment using distilled water. Separated rock surface and fractured parts fasten and/or fill up the boundaries of the rock blocks using epoxy resin for conservation of rock properties. Some brittle surface was treatment with water repellent consolidant of ethyl silicates, and heterogeneous surface carried out color matching by acrylic pigments. Upper part of the Buddha statue dig out small ditch for rain water drainage, and near surface of the Buddha statue treat removal works for lichen, weeds and bush. The duration capacity of the Buddha constituting rocks are degraded by various weathering factors, therefore we suggest that this Buddha statue have need to do long term monitoring and synthetic conservation researches.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.193-206
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• 2004

예로부터 빛고을로 인식되었던 광주가 근세에 이르러 의병활동, 광주학생운동, 5\ulcorner18민주화운동, 아직도 끝나지 않은 이념전쟁으로만 비추어질 수도 있는 지역의 이미지를 재정립하고, 도시 경쟁력의 증대를 위한 방안으로 CI사업 추진계획을 수립하고 3개년에 걸쳐(1999～2001) CI전략 개발, CI디자인 개발, 문화상품 개발, 도시환경디자인 개발 등을 추진하였다. 최근 커뮤니케이션에 있어서 캐릭터는 정보의 시각화라는 측면에서 다른 그래픽 심볼에 비해 설득적이라 할 수 있고, 기존의 심볼의 이미지 보완적 보조심볼로서의 개념이 아닌 독자적인 영역이 구축되어야 하므로 광주광역시 캐릭터 개발은 Character Identity 차원에서 메인캐릭터와 이를 각각의 용도에 맞춰 응용전개시키는 이벤트 캐릭터, 브랜드캐릭터로 구분하여 유형에 따라 다르게 적용되어야 할 적용성 및 활용성에 중점을 두고 개발되었다. 광주광역시의 메인캐릭터 개발컨셉은 "빛"과 "생명"으로 결정된 TCI이념을 활용하는 것과 광주의 상징 요소로서 "무등산"을 활용하는 두 가지 방향에서 개발이 진행되었으며, 1999년 10월의 TCI 추진회의 1차선정을 시작으로 광주시민을 포함한 전국민 설문조사와 2000년 4월의 의회설명회에 이르기까지 다양한 방법을 통해 캐릭터 개발안에 대한 평가와 검토/수정과정을 거쳐 기본캐릭터를 완성하게 되었다. 이를 통해 본 광주광역시의 캐릭터는 중장기적으로 치밀하게 계획되고 실천되어야 하며 변화하는 환경에 효율적으로 대응하는 구체적이고 실천적인 연구평가와 접근방법에 대한 연구 등으로 그 지역의 특징적인 문화를 상품화시키려는 노력이 캐릭터개발을 토대로 뒤따라야 한다. 촉진, 중요 연구 주제의 도출 및 연구 진행 계획을 수립하고, 국제적 산학 협력 강화를 통해 공동 연구를 도출하는 자리를 마련함. $\textbullet$본 학술회의에서 발표된 논문들을 취합하여, 논문집 및 CD-ROM을 제작하여 세계적 수준의 연구 결과를 알리고 이 분야에 관련된 학문, 기술 발전에 큰 도움이 됨.emove effectively radioactivity with in Adsorbent. As cleaning heavy water adsorbent and drying on each condition (temperature for drying and hours for cleaning). Because there is something to return heavy water adsorbent by removing impurities within adsorbent when it is dried o high temperature. After operating, we have been applying this research to the way to dispose heavy water adsorbent. Through this we could reduce solid waste products and the expense of permanent disposal of radioactive waste products and also we could contribute nuclear power plant run safely. According to the result we could keep the best condition of radiation s