• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2000.11a
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• pp.7-11
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• 2000

본 논문에서는 불완전 동기(Imperfect Synchronization)로 인한 칩 동기 에러(timing errors)와 위상 에러(phase errors)를 고려 하여 비동기(Asynchronous) DS-CDMA 시스템의 성능을 이론적으로 분석하였다. 성능 개선 기법으로는 다단 간섭제거기 (Multistage PIC)와 부분 다단 간섭제거기(Partial Multistage PIC)를 채용하였고 칩 동기 에러와 위상 에러가 두 간섭제거기의 간섭제거능력에 미치는 영향의 정도를 정량적으로 분석하였다. 성능분석 결과로부터 칩 동기 에러와 위상 에러로 인한 1단(no cancellation)에서의 성능 열화가 각 단의 상관기 출력(decision statistic)에 영향을 줌으로써 다단 간섭제거기와 부분 다단 간섭제거기의 성능 개선폭을 감소시켰다. 그렇지만, 불완전 동기에도 불구하고 단(stage) 수가 증가할수록 두 간섭제거기 모두 강한 간섭제거능력을 보였다. 실제 시스템에서는 성능 개선과 구현상의 복잡도를 동시에 고려해야하므로 다단 간섭제거기 보다 구조가 간단하고 계산량이 적은 부분 다단 간섭제거기의 활용도가 높아질 것이 예상된다.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.2
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• pp.169-175
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• 2007

The Bio Best Bacillus(B3) and Rotating Activated Bacillus Contactor(RABC) processes, in which Bacillus strains are predominating, are reported to remove nitrogen and phosphorus as well as organic matter effectively. Nevertheless the nutrient removal characteristics of the Bacillus strains have not been studied in detail so far. This study investigated the organic and nutrient removal by Bacillus strains, Bacillus megaterium(KCTC 3007), Paenibacillus polymyxa(KCTC 3627), and Bacillus sp. A12, C21, F12, and L1(isolated from a B3 process), by incubating the strains in 0.2% nutrient broth at $30^{\circ}C$. Burkholderia cepacia(KCTC 2966), a common activated sludge organism, was used as a reference species for comparison. Although the degradation rate was affected by the population sire, the specific removal rates of organic matter by Bacillus strains were greater by $2\sim5$ times than that of Burkholderia. In particular, the culture bottles inoculated with the endospores of Bacillus megaterium and Bacillus sp. C21, F12, and N12 showed significantly higher degradation rate than those of vegetative cells.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.43-50
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• 1996

A series of domestic natural zeolites were investigated to identify the phase and to study the capability of $NH_4{^+}$-ion removal from solution system. It was proved that the natural zeolite from Young-II bay area was thermally unstable zeolite, heulandite by XRD and FT-IR analyses. In addition, the heulandite exchanged by $K^+$ ion showed the highest thermal stability upon heat-treatments. However, the best capability of removing $NH_4{^+}$-ion from the solution system was the non-exchanged zeolite.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.119-124
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• 2006

The purpose of this study was the comparison of pollutants removal and the track study of the nitrogen and phosphorus, the estimation of the nitrification and denitrification rate, and the investigation of the nitrogen mass balance between intermittently aerated membrane bioreactor(IAMBR) and intermittently aerated bioreactor(IABR), thus it verified the validity of the membrane submergence. As a result, it had no difference of organic matter removal, however, IAMBR showed better efficiency than IABR in the nutrients. Also, $NO_3{^-}$-N concentration at the anoxic state in the reactor was lower in IAMBR, and the denitrified nitrogen of IAMBR was 40.9%, that of IABR was 10.7%, thus it found out that the denitrification capability of IAMBR was higher than IABR above fourfold. Therefore, it seems resonable to conclude that the membrane helps to improve the removal of pollutants, because of the high MLSS concentration and the available method of intermittent inflow/outflow.

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.306-308
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• 2002

원자로냉각재계통(Reactor Coolant System) 및 사용 후 저장조정화계통(Spent Fuel Pool Purification System)에는 양ㆍ음이온 교환수지가 충진된 혼상 이온교환수지탑을 설치하여 계통수에 존재하는 방사성 핵종을 제거하고 있으며, 정화율을 나타내는 제염계수(Decontamination Factor)가 특정값 이하이면 수지를 교체하고 있다. 그러나 특정 핵종에 대한 제염계수가 수지 사용기간에 관계없이 기준값 이하로 나타나고 있고, 수지탑의 성능을 예측하고 있지 못하는 실정이다. 원자력발전소 1차 계통에 설치되어 불순물을 제거하는 이온교환 수지탑에 대한 연속화학평형모델에 적용한 결과 수지탑에서 이온 용출은 수지에 대한 이온 선택도 순서와 동일하고 냉각재계통에는 붕산이 주성분이므로 음이온수지에서 붕산이 가장 먼저 누출된다. 그리고 붕산으로 포화된 음이온수지의 음이온 불순물 제거능력은 저하되지 않으며, 리튬으로 포화된 양이온수지의 양이온 불순물 제거능력은 저하된다.

• Korean Journal of Environmental Agriculture
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• v.30 no.3
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• pp.310-315
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• 2011

BACKGROUND: Heavy-metal pollution represents an important environmental problem due to the toxic effects of metals, and their accumulation throughout the food chain leads to serious ecological and health problems. METHODS AND RESULTS: Optimum conditions in continuous-flow stirred tank reactor (CSTR) and packedbed column contactor (PBCC) using brown seaweed biosorbent were investigated. Under optimum conditions from both lab-scale biosorbent systems, removal efficiency of copper (Cu) in a large-scale PBCC system was investigated. Removal capacity of Cu using brown seaweed biosorbent in a lab-scale CSTR system was higher than that in a lab-scale PBCC system. On the other hand, over 48 L/day of flow rate in Cu solution, removal efficiency of Cu in a lab-scale PBCC system was higher than that in a lab-scale CSTR system. Optimum flow rate of Cu was 24 L/day, optimum Cu solution concentration was 100 mg/L. Removal capacity of Cu at different stages was higher in the order of double column biosorption system > single column biosorption system. Under different heavy metals, removal capacities of heavy metal were higher in the order of Pb > Cr > Ni > Mn ${\geq}$ Cu ${\geq}$ Cd ${\fallingdotseq}$ Zn ${\geq}$ Co. Removal capacity of Cu was 138 L in a large-scale PBCC system. Removal capacity of Cu a large-scale PBCC system was similar with in a lab-scale PBCC system. CONCLUSION(s): Therefore, PBCC system using brown seaweed biosorbent was suitable for treating heavy metal wastewater.

• Proceedings of the KSEEG Conference
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• 2001.04a
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• pp.4-6
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• 2001

• Proceedings of the KAIS Fall Conference
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• 2002.05a
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• pp.124-126
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• 2002

폴리우레탄의 특징을 이용하여 폴리우레탄에 흡습능력 과 탈취능력을 향상시키고 향의 서방성 능력을 첨가하여 장루 환자들이 사용하기에 적합한 패드의 특징을 테스트 후 분석하였다. 수분의 흡습능력, 변의 냄새제거 정도의 탈취 능력 , 향의 지속성을 측정하였다. 폴리우레탄만의 특징으로도 흡습능력과 탈취능력이 있지만 주흡습제 보조흡수제를 첨가하고, 소취 제와 보조제를 첨가하여 더욱 개선된 흡습능력과 탈취능력을 확인하였다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.314-317
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• 2008

본 연구에서는 백탄과 흑탄에서 농약의 제거 능력을 비교하였고, 연속 실험을 통하여 시간의 경과에 따른 농약의 제거율 변화를 평가하는 것을 목적으로 하였다. 실험에 사용된 농약은 Simazine, Diazinon, Fenitrothion, Butachlor, Malathion이다. 회분식 실험 결과에 따르면, 흑탄과 백탄 양을 0.1g, 1g, 10g, 50g씩 증가시킬수록 각 농약 성분의 제거율이 높아지는 것으로 나타났으며, 농약성분에 따른 제거율을 보면, Malathion과 Butachlor는 혹탄에서 상대적으로 잘 제거가 되는 것으로 나타났다. 하지만 Diazinon은 흑탄의 회분식 실험, 연속식 실험 모두 상대적으로 낮은 제거율을 보였다.

• Journal of Wetlands Research
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• v.10 no.3
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• pp.1-7
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• 2008

In this study, the nutrient removal capacity of paddy field was investigated. Paddy field was considered as a constructed wetland. The present study was conducted during a cropping period in a rice cultivation area located in Hampyung-gun, Jeollanamdo, Korea. Water balance and mass balance of nutrients were estimated after intensive field monitoring. The surface runoff losses of T-N and T-P were 20.82 kg/ha and 1.55 kg/ha, respectively. The losses were 13.2% and 6.4% of T-N and T-P input into paddy fields, respectively. The results showed that the paddy fields have nutrient removal function.