• 한국유기농업학회지
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• 제20권3호
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• pp.357-368
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• 2012

탄질비가 다른 유기자재 시용이 토양중 무기태질소의 시기별 변화와 수수${\times}$수단그라스 교잡종의 질소이용률에 미치는 영향을 조사하기 위해서 2009년부터 2011년까지 수행되었다. 처리구는 질소함량 210kg/ha 수준으로 축분퇴비, 알팔파, 유박, 포함하였다. 유박은 가장 낮은 탄질비를 나타내었고, 축분퇴비는 3년 동안 가장 낮은 질소의 무기화가 관찰되었다. 토양 무기성분과 수수${\times}$수단그라스 교잡종의 건물중은 처리에 따라 일관성 있게 영향을 받지 않았고, 건물중은 재배기간인 5월부터 9월까지의 강수량과 부의 상관관계를 나타내었다. 화학비료는 2009년과 2010년에 질소이용률을 크게 증가시켰고, 축분퇴비는 3년간 가장 낮은 질소이용률을 보였다. 6월부터 8월까지의 강수량 증가는 퇴비로 처리된 수수${\times}$수단그라스 교잡종의 질소이용률을 다소 증가시켰으나 양분의 무기화가 빠른 화학비료는 반대의 양상이 관찰되었다. 본 시험에서는 유기자재의 탄질비 보다는 강수량의 변동이 클 때 작물의 건물중과 질소이용률에 영향을 끼치므로 이를 고려하여 밭토양에 시비를 해야 할 것으로 판단되었다.

• 조명전기설비학회논문지
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• 제22권12호
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• pp.122-129
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• 2008

본 논문은 실내에 잔존하는 직경 1[${\mu}m$] 이하의 미세먼지들을 집진하기 위하여 전기집진기를 설계하였으며, 이때 집진 효율의 극대화를 위하여 전계와 동시에 자계를 수직 및 수평으로 배치함에 따른 실험실 공기중에 포함된 미세먼지의 집진특성에 대하여 논하였다. 전계에 수평으로 자계를 인가한 경우는 자계의 유무 및 자석의 수량에 관계없이 집진효율이 거의 일정하게 나타났으며, 자석을 수평으로 배치하여 전계에 수직으로 인가한 경우는 비자화 페라이트 막대를 부착한 경우보다 약 5[%] 이상 집진효율이 향상되었다. 또한, 자계를 전계에 수직으로 인가하는 방법에 있어서, 자석을 접지전극의 가운데 정렬한 경우는 인가전압 5[kV]에서의 집진효율이 $17{\sim}32[%]$로서 자석을 앞쪽에 설치한 경우와 유사하였으며, 지그재그 및 안쪽 끝에 정렬시킨 경우는 집진효율이 $17{\sim}38[%]$로서 향상되었으며, 특히 0.7 및 1[${\mu}m$]의 굵은 입자들에 대한 집진특성이 양호하였다. 따라서, 전기집진기의 집진특성을 향상시키기 위해서는 자계를 전계에 수직으로 접지전극의 중간 또는 지그재그 식으로 배치하는 것이 가장 적절한 것으로 판단된다.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.516-522
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• 2023

The co-precipitation process plays a key role in the decontamination of radionuclides from low and intermediate levels of liquid waste. For that reason, the removal of Cs ions from waste solution by the co-precipitation method was carried out. A simulated liquid waste (¹³³Cs) was prepared from a 0.1 M CsCl solution, while wastewater generated by washing steel ash served as a representative of radioactive cesium solution (¹³⁷Cs). By co-precipitation, potassium ferrocyanide was applied for the adsorption of Cs ions, while nickel nitrate and iron sulfate were selected for supporting the precipitation. The amount of residual Cs ions in the CsCl solution after precipitation and filtration was determined by ICP-OES, while the radioactivity of ¹³⁷Cs was measured using a gamma-ray spectrometer. After cesium removal, the amount of cesium appearing in both XRD and SEM-EDS was analyzed. The removal efficiency of ¹³³Cs was 60.21% and 51.86% for nickel nitrate and iron sulfate, respectively. For the ash-washing solution, the removal efficiency of ¹³⁷Cs was revealed to be more than 99.91% by both chemical agents. This implied that the co-precipitation process is an excellent strategy for the effective removal of radioactive cesium in waste solution treatment.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.143-143
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• 2022

Precipitation plays an essential role in water resources management and disaster prevention. Therefore, the understanding related to spatiotemporal characteristics of rainfall is necessary. Nowadays, highly accurate precipitation is mainly obtained from gauge observation systems. However, the density of gauge stations is a sparse and uneven distribution in mountainous areas. With the proliferation of technology, satellite-based precipitation sources are becoming increasingly common and can provide rainfall information in regions with complex topography. Nevertheless, satellite-based data is that it still remains uncertain. To overcome the above limitation, this study aims to take the strengthens of machine learning to generate a new reanalysis of precipitation data by fusion of multiple satellite precipitation products (SPPs) with gauge observation data. Several machine learning algorithms (i.e., Random Forest, Support Vector Regression, and Artificial Neural Network) have been adopted. To investigate the robustness of the new reanalysis product, observed data were collected to evaluate the accuracy of the products through Kling-Gupta efficiency (KGE), probability of detection (POD), false alarm rate (FAR), and critical success index (CSI). As a result, the new precipitation generated through the machine learning model showed higher accuracy than original satellite rainfall products, and its spatiotemporal variability was better reflected than others. Thus, reanalysis of satellite precipitation product based on machine learning can be useful source input data for hydrological simulations in ungauged river basins.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E2호
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• pp.97-106
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• 2002

The purpose of this study was to quantitatively estimate the washout removal efficiencies of criteria air pollutants such as SO$_2$, TSP, PM10, CO, NO$_2$, and O$_3$corresponding to the amounts and durations of precipitation. The removal patters by washout were studied with air pollutants data and the corresponding precipitation data in Seoul, Korea during the periods of 1990 to 1999. In addition, washout patterns were classified into four seasons and four time Bones, i.e., night, morning, afternoon, and evening. In this study, natures of air pollutants by sequential precipitation were also intensively studied by examining the linear relationships between removal efficiencies and the amounts and durations of precipitation for each pollutant. The results of this study showed that SO$_2$, TSP, and O$_3$were rapidly removed by initial precipitation; however, NO$_2$was slowly removed 2-hour after precipitation. Both CO and PM10 were weakly removed by washout and their removal patters showed to be irregular.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2665-2668
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• 2014

Aptamers are oligonucleotides or peptide molecules that are able to bind to their specific target molecules with high affinity via molecular recognition. In this study, we present development of aptamer-based precipitation assays (or simply aptamoprecipitation) for His-tagged proteins and thrombin to compare their purification efficiency with other conventional affinity precipitation methods. A crosslinking method was employed to immobilize thiol-functionalized aptamers onto the surface of polystyrene resins, enabling them to specifically bind to His-tag and to thrombin, respectively. The resulting aptamer-functionalized resins were successfully applied via a one-step experiment to purification of His-tagged proteins from complex E. coli and to thrombin extraction, exhibiting superior or at least comparable purification results to the conventional immobilized metal affinity precipitation or immunoprecipitation.

• 한국입자에어로졸학회지
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• 제14권1호
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• pp.9-16
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• 2018

We have developed an electrostatic precipitation (ESP) type air cleaner for indoor air quality and investigated its performances regarding CADR (Clean air delivery rate), single-pass efficiency and gas removal efficiency. The ESP air cleaner used an ACF (Activated carbon fiber) filter for gas removal and the ACF as a high voltage electrode for particle removal. The ESP air cleaner was tested in a chamber with the volume of $1m^3$ regarding CADR and gas removal efficiency. The applied CADR area of the ESP was $1.8m^2$. Gas removal efficiency was tested with 3 gases (Acetaldehyde, Acetic acid, Ammonia). As the results of the gas removal efficiency, the ESP air cleaner shows the removal efficiencies of 90, 98 and 85% for acetaldehyde, acetic acid and ammonia, respectively.

• 대한환경공학회지
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• 제28권12호
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• pp.1304-1309
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• 2006

정수처리 과정에서 Cryptosporidium과 유사한 특성을 가지고 있는 C. tracer를 이용하여 공정별 제거효율을 조사하였다. PACI(Poly aluminium chloride, $Al_2O_3$(10%)) 주입량이 10 mg/L일 때 C. tracer는 97.16%로 가장 높은 제거율을 보였으며, 탁도 제거율과 SS 제거율이 높을수록 C. tracer 응집 효율이 높았다. 원수의 pH가 높을수록 C. tracer 제거율이 증가 하였으며 응집 침전 후의 유출수 탁도와 C. tracer 제거율과의 상관성이 $R^2=0.9506$로 높게 나타나 응집 침전 후의 유출수 탁도로 Cryptosporidium 제거 효율을 평가할 수 있음을 알 수 있었다. 또한 여과 실험에서는 유입 탁도에 따른 C. tracer 제거율은 $94.00{\sim}95.83%$ 범위였으며 유출수 탁도와 C. tracer 제거율과의 상관성은 $R^2=0.8704$였다. 최적 응집 조건 하에서 여과수 탁도가 양호할 경우, 예상되는 Cryptosporidium의 제거율은 응집 침전의 경우 1.55 log(97.16%), 급속모래여과의 경우 1.38 log(95.83%), 응집 침전+급속모래여과의 경우 2.31 log(99.51%)로 나타났다.

• 대기
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• 제19권3호
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• pp.243-253
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• 2009

In other to interpret the long-term variations of sunshine duration, cloud lifetime, and precipitation intensity observed in and around Seoul and Busan for the period from 1986 to 2005, aerosol indirect effect was employed and applied. For the identification of long-term trend of aerosol concentration, observed visibility and AOT of AERONET sunphotometer data were also used over the same regions. The result showed that the time series of visibility was decreased and those of AOT increased, especially trends were remarkable in 2000s. In both regions, occurrence frequencies of observed cloudiness (cloud amount ${\leq}6/10$) and strong precipitation (rain rate > $0.5mmhour^{-1}$) have been steadily increased while those of cloudiness (cloud amount > 7/10) and weak precipitation (rain rate ${\leq}0.2mmhour^{-1}$) decreased. These results are corresponding to the trend of both visibility and AERONET data, implying the aerosol indirect effect that makes size of cloud droplet reduce, cloud life-time longer and precipitation efficiency decreased. Our findings demonstrate that, although these phenomena are not highly significant, weather and climate system over Korean urban area have been changed toward longer lifetime of small cloudiness and increasing precipitation intensity as a result of increased aerosol indirect effect.

• Korean Chemical Engineering Research
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• 제60권4호
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• pp.544-549
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• 2022

본 연구에서는 음압 캐비테이션 아세톤-펜테인 분별침전으로 Taxus chinensis로부터 파클리탁셀의 침전 효율을 획기적으로 개선하였다. 음압 -200 mmHg에서 침전할 경우 짧은 조업 시간(5분)에 대부분의 파클리탁셀을 회수(>99.9%) 할 수 있었다. 침전 속도 상수는 대조군 대비 1.512~5.073배(-50~-200 mmHg) 증가하였다. 음압으로 활성화에너지는 -3737~-6536 J/mol 감소하였으며, 이로 인해 침전 속도가 증가하였다. 또한 음압 도입으로 침전물 크기는 5.3배 감소하였으며, 파클리탁셀의 확산 계수는 7.0배 증가하였다.