• 공업화학
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• 제30권4호
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• pp.408-414
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• 2019

본 연구에서는 전통적인 열수추출법과 초음파 추출법을 이용하여 민들레에서 항산화성분을 추출하였다. 추출 후 추출수율과 항산화성분인 플라보노이드 함량을 최적화하기 위해 반응표면분석법 중 Box-Behnken 설계모델을 이용하여 추출하였다. 열수추출법의 경우 추출온도, 주정/초순수 부피비, 추출시간을 변수로 설정하였으며, 초음파 추출법의 경우 초음파 조사세기, 주정/초순수 부피비, 초음파 조사시간을 변수로 설정하였다. 열수추출법의 최적 추출조건은 추출온도($45.76^{\circ}C$), 주정/초순수 부피비(41.92 vol.%), 추출시간(1.75 h)이었다. 또한 초음파 추출법의 최적조건은 초음파 조사세기(512.63 W), 주정/초순수 부피비(56.97 vol.%), 추출시간(20.79 min)이었다. 이 조건에서 예상되는 반응치는 수율(22.09 wt.%), 플라보노이드 함량(28.98 mg QE/mL dw)으로 산출되었다. 또한 실제실험 결과 오차는 3% 이하로 나타나 최적화의 타당성을 입증하였다.

• Journal of Microbiology and Biotechnology
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• 제6권5호
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• pp.358-360
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• 1996

Solvent extraction, soxhlet method, and supercritical fluid extracion were considered, respectively, as the method of choice for the recovery of DHA from lyophilized Thraustochitrium sp., and the results of corresponding extraction were compared. Supercritical fluid extraction seems to be the most appropriate process with respect to time, process simplicity, and extractant intoxicity.

• 대한치과의사협회지
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• 제57권6호
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• pp.326-332
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• 2019

Extraction treatment has been used for a long time to treat crowding or lip protrusion patients and still extraction decision is the most difficult and important decision during diagnosis and treatment planning. If the amount of crowidng is severe, premolar extraction is often considered. Because of their location, premolar extractions would seem to allow for the most straightforward relief of crowding and the improvement of soft tissue profile. But patients and their parents often prefer nonextraction approach if possible and such a preference gives us serious question about the boundary of nonextraction treatment. Because Orthodontic Mini-Implant (OMI) become popular these days, distalization of posterior teeth can be obtained easily without patient's compliance. For this reason, many orthodontists are trying to treat crowding patient with nonextraction than before. But sometime, unexpected side effects are observed including unesthetic profile, impaction of second molar and long treatment time. All the tools for space gaining - extraction, arch expansion, molar distalization and interproximal enamel reduction - have their limitations and indications. Possible side effects and limitations should be carefully considered during the treatment planning. Although Korean patients usually require extraction more often than US or European patients, more knowledge about the tools for space gaining would help us to decrease the rate of extraction and the problems during treatment of crowding patients.

• 산업기술연구
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• 제27권B호
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• pp.161-167
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• 2007

The objetives of this study are to set up optimum extraction temperature, time and organic solvent for propolis extraction, to investigate chemical properties, and to develop health foods from propolis preparation. In this study, ethanol and ultrasonic extracts method performed to optimum extraction temperature was at 60, $20^{\circ}C$, optimum extraction time was at 12, 4 hours and optimum extraction amount of solvent was at 20, 15 times of propolis weight. When various ethanol solutions were used, whereas flavonoid content was highest in 70, 80% aqueous ethanol, respectively. So the ultrasonic extracts method used gave better results than the ethanol extracts method in this work. Extraction of propolis with etanol and ultrasonic extracts method was performed by using the water and various concentrations of aqueous ethanol as solvent. Sensitivity of propolis samples to Staphylococcus aureus was investigated and the results were shown. Samples of water extract did not inhibit microbial growth, where as 50% aqueous ethanol extract the largest inhibitory zone for Staphylococcus aureus, then decreased inhibition with increasing ethanol concentrations.

• Korean Chemical Engineering Research
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• 제55권4호
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• pp.503-509
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• 2017

The present experimental study proposed two ionic liquids (ILs) namely [Aliquat 336] [$HSO_4$] (prepared and characterized at our laboratory) and Cyphos 101 IL (supplied by Cytec Company) dissolved in two different diluents such as DCM (di-chloro-methane) and toluene applied for PMs extraction. The first IL [Aliquat 336] [$HSO_4$] prepared and confirmed the formation of final product by using FT-IR and TGA studies. The primary experiment in solvent extraction processing is kinetic effect; 0 to 30 time varied for PMs by using two ILs and confirmed the optimized extraction equilibrium time. This study was conducted for PMs (Pt, Rh and Cu) extraction and separation from each other by using proposed ILs. This is the primary study of the utilizing green solvents such as ILs as an extractant system for Pt, Rh and Cu extraction and possible separation.

• 산업식품공학
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• 제21권1호
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• pp.79-87
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• 2017

본 연구는 홍삼정과 부산물의 산업적 이용성 증대를 위하여 중 반응표면분석법을 이용한 추출수율 및 총 진세노사이드 함량 추출 최적조건을 찾는데 목적이 있다. 추출용매 농도(에탄올, 30-70%, v/v), 추출온도($25-70^{\circ}C$), 추출시간(5-11 hr) 등의 독립변수를 D-optimal design을 통하여 실험계획하고, 얻어진 실험결과를 반응표면분석하여 추출수율, 총 진세노사이드 함량 등의 반응변수에 대한 최적 추출조건을 검토하였다. 그 결과, 독립변수인 추출온도와 시간이 증가함에 따라 수율 및 총 진세노사이드 함량은 증가하였으나, 추출용매(에탄올)의 경우 고농도에서 수율은 감소한 반면, 추출물 중 총 진세노사이드 함량은 증가하였다. 독립변수 중 추출용매의 농도가 각 반응변수에 가장 큰 영향을 주는 것으로 나타났다. 본 연구를 통해서 유도된 회귀식 모형은 실험을 통해 얻은 결과와 잘 일치하였고, 추출수율과 총 진세노사이드 함량을 최대로 하는 최적 조건은 추출용매농도 57.90% (v/v), 추출온도 $56.94^{\circ}C$, 추출시간 11시간으로 이 경우 추출수율은 84.52%, 총 진세노사이드 함량은 9.54 mg/g으로 예측하였다.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1996년도 추계학술대회 학술발표 논문집
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• pp.294-297
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• 1996

This paper proposes the method to recognize of time series data based on the chaotic feature extraction. Features extract from time series data using the chaotic time series data analysis and the pattern recognition process is using a neural network classifier. In experiment, EEG(electroencephalograph) signals are extracted features by correlation dimension and Lyapunov experiments, and these features are classified by multilayer perceptron neural networks. Proposed chaotic feature extraction enhances recognition results from chaotic time series data.

• KSBB Journal
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• 제24권2호
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• pp.212-215
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• 2009

본 연구에서는 식물세포배양으로부터 항암물질 paclitaxel을 고 순도, 고 수율로 분리 가능한 액-액 추출 공정에서의 주요 공정 변수들을 최적화 하였다. 액-액 추출을 위한 최적의 유기용매 (methylene chloride) 첨가량, 추출횟수, 혼합시간, 정체시간은 각각 0.28 (v/v), 3 (times), 30 min, and 40 min 임을 알 수 있었다. 액-액 추출 공정은 특히 메탄올을 이용한 biomass 추출물에 포함되어 있는 다량의 극성불순물을 제거하는데 매우 효과적이었다. 또한 액-액 추출 후 농축조건으로는 후속공정에서의 높은 순도의 paclitaxel 뿐만 아니라 작업의 용이성 측면에서 액-액 추출액을 rotary evaporator로 완전히 농축하는 것이 가장 바람직함을 알 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.90.1-90
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• 2002

Counters for the various kinds of bank notes require high-speed distinctive point extraction and recognition for notes. In this paper we propose a new point extraction and recognition algorithm for bank notes. For distinctive point extraction we use a coordinate data extraction method from specific parts of a bank note representing the same color. The recognition algorithm uses a back-propagation neural network that has coordinate data input. The proposed algorithm is designed to minimize recognition time.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.647-650
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• 1999

In this Paper, we propose an optimal feature extraction for multiclass problems through proper choice of initial feature vectors. Although numerous feature extraction algorithms have been proposed, those algorithms are not optimal for multiclass problems. Recently, an optimal feature extraction algorithm for multiclass problems has been proposed, which provides a better performance than the conventional feature extraction algorithms. In this paper, we improve the algorithm by choosing good initial feature vectors. As a result, the searching time is significantly reduced. The chance to be stuck in a local minimum is also reduced.