• 공업화학
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• 제5권1호
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• pp.121-126
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• 1994

초산의 반응추출에 미치는 영향을 규명하기 위하여 추출제로 2급과 3급 아민 및 용매화 추출제, 용매로 n-butylacetate, modifier로 4-nonylphenol, TBP 및 isodecanol을 이용하였다. 그외에 수용액상의 pH와 온도의 영향을 연구하였다. 실험결과 초산의 추출에서 3급 아민인 tril-n-octyl과 tri-n-decylamine의 50% 혼합 추출제인 MODA가 추출도 및 선택도에서 가장 좋았다. Modifier로서는 4-nonylphenol이 우수하였다. 이외에도 수용액의 pH와 추출계의 온도가 낮을수록 추출도가 높았다.

• Bulletin of the Korean Chemical Society
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• 제25권6호
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• pp.873-877
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• 2004

The relationship between the behaviors of c.c.lipase back-extraction and their percolation phenomena by using AOT reverse micellar systems (RVMS) has been studied by the addition of a small amount of additives to organic phase such as thiols and nonionic-surfactants focusing on micelle-micelle interactions. The values of ${\beta}_t$ defined by the variation of percolation processes and back-extraction behaviors of c.c.lipase have a good linear correlation. The hydrophobicity of additive molecules suppressing the cluster formation of reverse micelles (high values of ${\beta}_t$) improved the back-extraction behavior of c.c.lipase. The back-extraction fraction and its rate of c.c.clipase are increased with decreasing of the value of hydrophilic lipophilic balance (HLB) and increasing of the hydrophobicity per additive molecules added to reverse micellar systems (RVSM) in the same additives concentration.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.179-182
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• 2004

This study reports the extraction behavior of $\alpha$-lactalbumin using bis(2-ethylhexyl) sulfosuccinate sodium (AOT) reverse micelles. Forward extraction of $\alpha$-lactalbumin in the reverse micellar organic phase from aqueous feed solutions was strongly dependent on the AOT concentration and the complete forward extraction of 0.03 mM $\alpha$-lactalbumin was successfully achieved at an AOT concentration of ca. 100 mM. A similar dependency of the forward extraction on the AOT concentration was obtained in isooctane, n-hexane, and n-octane systems. In the backward extraction from the micellar organic phase, the recovery of the protein as high as ca. 90% was obtained with pH control and/or salt addition.

• Bulletin of the Korean Chemical Society
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• 제22권8호
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• pp.897-902
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• 2001

The protein back-extraction processes were discussed from the viewpoint of the micelle-micelle interaction. Bovine serum albumin (BSA) suppressing the cluster formation of reverse micelle (positive value of ${\beta}pr)$ has the high back-extra cted fraction (Eb), but cytochrome c enhancing the formation of reverse micelle (negative value of ${\beta}pr)$ has the low back-extracted fraction, relatively. We have also examined quantitatively the effects of alcohol addition and protein solubilization on the percolation process of reverse micelle. The alcohols suppressing the formation of micellar cluster (high values of ${\beta}t)$, remarkably improved the back-extraction rates of BSA and cytochrome c. The values of ${\beta}t$, defined by the variation of percolation process, and the back-extraction behavior of proteins have a good linear correlation. These results indicate that the micelle-micelle interaction or micellar clustering plays an important role in the back-extraction process of proteins.

• 방사성폐기물학회지
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• 제18권4호
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• pp.457-464
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• 2020

In this study, extraction of uranium(VI) from an aqueous nitric acid solution was investigated using tri-n-butyl phosphate (TBP) as an extractant in an ionic liquid, 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]). The distribution ratio of U(VI) in 1.1 M TBP/[Cnmim][Tf2N] was significantly high when the concentration of nitric acid was low. The value of the distribution ratio decreased as the concentration of the nitric acid increased at lower acidities, and then increased with a nitric acid concentration of up to 8 M. This can be attributed to the different extraction mechanisms of U(VI) based on nitric acid concentrations. Thus, a cation exchange at low acidity levels and an ion-pair extraction at high acidity levels were suggested as the extraction mechanism of U(VI) in the TBP/[Cnmim][Tf2N] system.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권1호
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• pp.1-6
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• 2015

The objectives of this study were to calculate the radius of influence (ROI) of well for an air-sparging (AS)/soil vapor extraction (SVE) system and to evaluate the applicability of the system applied for the remediation of the petroleum contaminated rail site. For air permeability test, three monitoring wells were installed at a location of 1.3 m, 2.3 m, 3.0 m from the extraction well. And the pressure of each monitoring well was measured by extracting air from the extraction well with the pressure and flow of $(-)2,600mmH_2O$ and $1.58m^3/min$. The ROI for an extraction well was calculated as 4.31 m. Air was injected into the injection well with the pressure and flow of $3,500mmH_2O$ and $0.6m^3/min$ to estimate the radius of influence for oxygen transfer. Oxygen concentrations of air from three monitoring wells were measured. The ROI of an injection well for oxygen transfer was calculated as 3.46 m. The 28 extraction wells and 19 injection wells were installed according to the ROI calculated. The AS/SVE system was operated eight hours a day for five months. The rail site was contaminated with the petroleum and concentrations of benzene, toluene, and xylene were over the 'Worrisome Standard' of the 'Soil Environment Conservation Act'. The contaminated area was estimated as $732m^2$ and contaminants were dispersed up to (-)3 m from the ground. During the operation period, soil samples were collected from 5 points and analyzed periodically. With the AS/SVE system operation, concentrations of benzene, toluene, and xylene were decreased from 7.5 mg/kg to 2.0 mg/kg, from 32.0 mg/kg to 23.0 mg/kg, from 35.5 mg/kg to 23.0 mg/kg, respectively. The combined AS/SVE system applied to the rail site contaminated with volatile organic compounds (VOCs) exhibited a high applicability. But the concentration of contaminants in soil were fluctuated due to the heterogeneous of soil condition. Also the effect of the remediation mechanisms was not clearly identified.

• 한국광학회지
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• 제23권4호
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• pp.143-146
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• 2012

본 논문에서는 반도체 광 증폭기(Semiconductor Optical Amplifier)의 교차 진폭 변조 현상을 이용하여 광 컴퓨팅이나 광통신에서 데이터의 패킷 교환, 데이터 리셋 혹은 추가나 제거에 필수적인 전광 데이터 추출을 시뮬레이션하고 실험적으로 구현하였다. 전광 데이터 추출의 실험적 시뮬레이션에는 상용 프로그램인 VPI Tool을 사용하였으며 기본적으로 두 개의 반도체 광 증폭기(SOA)를 사용하여 AND 논리를 구성한 후 이를 이용하여 데이터를 추출하였다. 또한 높은 집적성과 효율로 고속으로 연산할 수 있는 가능성을 확인하였다.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4473-4482
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• 2010

한방의학에서 절진에 속하는 맥진은 28가지의 맥상 분석 방식을 기존의 아날로그 시스템에 적용하여 사용하였다. 그러나 아날로그 시스템은 ECG (Electrocardiogram)와 같은 특징점 추출방법을 이용해 맥파를 분석하는데 특징점 추출방법과 입력 신호의 과도한 증폭으로 맥파의 Clipping현상이 발생되어 맥파의 모양을 정확하게 분석할 수 없는 문제점들이 발생되었다. 본 논문에서는 이러한 아날로그 맥진기 시스템에 문제점을 보완하기 위한 방안의 하나로 전자 맥진기 시스템의 중요한 부분이라 할 수 있는 디지털 필터를 설계하기 위하여 신호의 특징점 추출을 위한 C-spline 보간법을 이용하고, signal modeling에 Prony's method로 디지털 필터를 설계하는 방법을 제안 하였다. 또한 기존의 아날로그 시스템에 맥파 분석 방법의 문제점을 보안하기 위한 전자 맥진기 시스템을 구성하여 새로운 맥파 분석 알고리즘과 아날로그 시스템에서 분석이 어려웠던 맥파의 모양 분석 알고리즘을 제안하였다. 증폭 단 이후 제안된 필터 설계방법을 이용하여 구성된 전자 맥진기 시스템의 출력 값이 아날로그 맥진기의 출력 파형과 아주 유사하면서 파형이 깨끗한 신호를 얻을 수 있어 설계방법의 적합성을 확인 하였고, 제안된 알고리즘에 의한 맥파 분석 결과가 아날로그 시스템의 맥파 분석 보다 정확한 맥파를 분석할 수 있었음을 확인할 수가 있었다.

• Journal of Biosystems Engineering
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• 제32권2호
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• pp.121-129
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• 2007

This study was conducted to elucidate extraction efficiency by microwave technique in comparison with sonication technique for extraction of insecticide residue in pear. In the analysis of the extraction efficiency of microwave for a pear spiked with imidacloprid, the extraction efficiency by microwave power of 300 W with extraction temperature of $80^{\circ}C$, heating time of 1 to 3 minute was shown to be similar with the extraction time 20 minutes by sonication. The optimal condition. in consideration of economical condition and treatment time, for microwave extraction of imidacloprid in the pear were 300 watts of power supply, $100^{\circ}C$ of extraction temperature, 1 minute of heating time and 10 mL of acetone volume. A new microwave vessel was developed to rapidly process the sample of the insecticide imidacloprid residues in the pear. This vessel was designed to include a reaction chamber and a filtration equipment, and a gathering chamber. The system could curtail a pretreatment time to 21 minutes than sonication and 7.9 minutes than the previous microwave vessel.

• 정보관리학회지
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• 제26권1호
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• pp.305-320
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• 2009

웹을 통해 제공되는 뉴스 페이지의 경우 필요한 정보 뿐 아니라 많은 불필요한 정보를 담고 있다. 이러한 불필요한 정보는 뉴스를 처리하는 시스템의 성능 저하와 비효율성을 가져온다. 이 연구에서는 웹 페이지로부터 뉴스 콘텐츠를 추출하기 위해 문장과 블록에 기반한 뉴스 기사 추출 방법을 제시하였다. 또한 이들을 결합하여 최적의 성능을 가져올 수 있는 방안을 모색하였다. 실험 결과, 웹 페이지에 대해 하이퍼링크 텍스트를 제거한 후 문장을 이용한 추출 방법을 적용하였을 때 효과적이었으며, 여기에 블록을 이용한 추출 방법과 결합하였을 때 더 좋은 결과를 가져왔다. 문장을 이용한 추출 방법은 추출 재현율을 높여주는 효과가 있는 것으로 나타났다.