• Food Science and Biotechnology
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• 제15권1호
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• pp.24-27
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• 2006

A simple HPLC quantification method was developed for genistein, genistin, daidzein, and daidzin in soybeans and soybean products. The procedure used a $4.6{\times}100\;mm$ $Chromolith^{(R)}$ RP-18e column with a mobile phase of 1% HOAc in 20% MeOH to 1% HOAc in 80% MeOH for 10 min. The injection volume was $2\;{\mu}L$ at a flow rate of 2 mL/min. Detection was carried out under UV at 254 nm. Under these conditions, the major isoflavones daidzein, daidzin, genistein, and genistin in soybean and soybean pastes were eluted within 7 min with baseline separation. Optimal extraction of the above four major isoflavones was achieved when 40 g of soybean or soybean paste was refluxed in 100 mL of 95% ethanol for 2 hr. Ten different soybean cultivars and nine commercial soybean pastes were analyzed by this method. The total isoflavone content was highest in the cultivar Somyung ($2,497\;{\mu}g/g$ dry weight). The isoflavone content in soybean pastes varied widely from manufacturer to manufacturer (an almost five-fold difference between the highest and lowest values). Such variations were presumably due to differences in fermentation conditions, type of soybeans used, and levels of such additives as starch and salt.

• 멤브레인
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• 제21권1호
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• pp.22-29
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• 2011

중전기의 유지 보수 및 교체 과정에서 절연체로 사용된 $SF_6$ 가스는 교체 충전과 정제과정에서 유입되는 공기와의 아크 방전에 의해 많은 종류의 부산물($N_2$, $O_2$, $CF_4$, $SO_2$, $H_2O$, HF, $SOF_2$, $CuF_2$, $WO_3$ 등)이 발생된다. 부산물 중에서도 대부분을 차지하는 것이 $N_2$, $O_2$, $CF_4$이며, $SF_6$가스를 재사용하기 위해서는 이들을 효과적으로 분리 회수하는 공정이 필요하다. 주요 부산물인 $N_2$, $O_2$, $CF_4$와의 분리 효율 측면에서 분리막법은 기존의 흡착, 심냉법에 비하여 상대적으로 높은 효율을 보이고 있어 이에 대한 관심 또한 증가하고 있다. 따라서 본 논문에서는 중전기 산업에서 발생되는 $SF_6$ 가스 함유 농도 90 vol% 이상의 가스에 대하여 분리막법을 적용하여 $N_2$, $O_2$, $CF_4$와 $SF_6$ 가스의 온도와 배출유량의 변화에 따른 분리 회수 가능성을 관찰하였다. PSF와 PC 중공사 분리막을 이용하여 고농도 $SF_6$에 대한 분리 회수 실험 결과, PSF 분리막의 최대 회수율은 압력 0.3 MPa, 온도 $25^{\circ}C$, 배출유량 150 cc/min에서 92.7%를 나타내었으며, PC 분리막에서는 압력 0.3 MPa, 온도 $45^{\circ}C$, 배출유량 150 cc/min 일 때 74.8%의 최대 회수율을 나타내었다. 또한, 사용된 두 가지 분리막과 운전 조건에서 주요 부산물인 $N_2$, $O_2$, $CF_4$의 최대 제거율은 각각 약 80%, 74%, 그리고 58.9%가 관찰되었다. 이로부터 분리막 공정은 고농도 폐 $SF_6$ 가스에서 주요 부산물로부터 $SF_6$의 효과적인 분리 및 회수가 가능한 공정으로 적용할 수 있는 가능성을 파악 할 수 있었다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.542-545
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• 2005

Spaceborne radar interferometry has been widely used to estimate the topography and deformation of the Earth. It is difficult to obtain coherent interferometric SAR pairs especially over coastal areas mainly because of variation of surface conditions. We carried out the experiment using a cross-interferometric pair with a perpendicular baseline of about 1.4 km, a 30 minutes temporal separation and the height sensitivity of about 6 meters. The temporal decorrelation can be reduced by the cross interferometric technique with a 30 minutes temporal separation. Accurate coregistration was performed through resampling of ENVISAT ASAR data to equivalent pixel spacing to the ERS SAR data, because of the differences of the pulse repetition frequency and range sampling rate between the two sensors. Then we estimated range and azimuth offset to a sub-pixel accuracy using image intensity cross correlation. A larger window chip size than a general case was used because it was difficult to distinguish typical features. As range bin increased, the difference of Doppler centroid also increased. It resulted in lower coherence in far range than in near range. Coherences over wetland in near and far range were about 0.8 and 0.5, respectively. The coherence was improved by applying azimuth and range common band filtering, but coherence gap still existed. ERS-ENVISAT cross-interferogram usually lost information in urban area. However, high coherence over a city in this pair was shown, because of less man-made structures than other major cities. Accuracy of the DEM constructed by the ERS-ENVISAT 30-minute pair in a coastal area is to be evaluated.

• 한국산업보건학회지
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• 제3권2호
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• pp.152-165
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• 1993

This study was performed at eleven small-sized plating factories located in Seoul, Incheon, Ansan, and Taejeon from July 21 to October 6, 1992. The major objectives of this study were to evaluate worker exposure to hexavalent chromium and local exhaust ventilation (L.E.V.) systems at the chromium plating operations. The most suitable L.E.V. systems for chromium plating tanks were designed as examples for recommendation to the industry. The results are summarized as follows. The range of chromium plating operations investigated included decorative, hard, and black chromium plating on several kinds of parts. Most of plating tanks were not equipped with proper control methods against emission of hexavalent chromium mists and workers were not wearing appropriate personal protectives. The ariborne hexavalent chromium concentrations showed an approximate lognormal distribution. The geometric means of both personal and area samples were within the Korean and ACGIH standards, $50{\mu}g/m^3$. However, in comparison with the NIOSH criterion, $1{\mu}g/m^3$, the geometric means of personal samples at two factories and the geometric means of area samples at two factories exceeded it. The geometric means of personal and area samples of high exposure groups (above the NIOSH criterion) were 7 and 27 times higher than those of low exposure groups (below the NIOSH criterion), respectively. The L.E.V. systems of high exposure groups were improperly designed, and the factory with the highest exposure level had no L.E.V. systems at all on chemical etching process. Whereas at factories of low exposure groups, mist control methods such as mist suppressants, tank cover, and/or auxillary L.E.V. systems were added to L.E.V systems. The evaluation of L.E.V. systems showed that there was no chromium plating operation satisfying the ACGIH criteria for capture velocity, slot velocity, and exhaust rate simultaneously. To increase performance of L.E.V. systems, it must be designed to minimize the impact of boundary layer separation. Push-pull ventilation hood and downward plenum ventilation hood were suggested for the Korean industry.

• Mass Spectrometry Letters
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• 제5권1호
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• pp.24-29
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• 2014

An advanced and reliable high performance liquid chromatography (HPLC)/ultraviolet detector (UV)/ion-trap time-of-flight (IT-TOF) mass spectrometry was developed for the simultaneous quantification of 19 marker compounds in Bang-poong-tong-sung-san (BPTS), a traditional oriental prescription. Various parameters affecting HPLC separation and IT-TOF detection were investigated, and optimized conditions were identified. The separation was achieved on a Capcell PAK C18 column ($1.5mm{\times}250mm$, $5{\mu}m$ particle size) using a gradient elution of acetonitrile and water containing 0.1% formic acid at a flow rate of 0.1 mL/min. The column temperature was maintained at $40^{\circ}C$ and the injection volume was $2{\mu}L$. IT-TOF system was equipped with an electrospray ion source (ESI) operating in positive or negative ion mode. The optimized electrospray ionization parameters were as follows: ion spray voltage, +4.5 kV (positive ion mode), or -3.5 kV (negative ion mode); drying gas ($N_2$), 1.5 L/min; heat block temperature, $200^{\circ}C$. Automatic $MS^n$ (n = 1~3) analyses were carried out to obtain structural information of analytes. Elemental compositions and their mass errors were calculated based on their accurate masses obtained from a formula predictor software. The marker compounds in BPTS were identified by comparisons between $MS^n$ spectra from standards and those from extracts. Moreover, the libraries of $MS^2$ and $MS^3$ spectra and accurate masses of parent and fragment ions for marker compounds were constructed. The developed method was successfully applied to the BPTS extracts and identified 17 out of 19 marker compounds in the BPTS extracts.

• 한국산학기술학회논문지
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• 제17권1호
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• pp.21-27
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• 2016

온실가스로 인한 지구 온난화는 전 세계적인 주요 문제로 인식되고 있으며, 많은 나라들은 $CO_2$ 배출 감축을 위한 많은 노력을 하고 있다. 연소 후, 연소 전, 순산소 연소의 다양한 $CO_2$ 포집 기술들이 개발되고 있으며, 그 중 본 연구에서는 연소 전 $CO_2$ 포집 기술로서 수성가스전환반응기와 기체분리막의 융합 시스템을 고찰하였다. CO 전환율을 높이기 위해 고온 수성가스반응과 저온 수성가스반응이 결합된 2단 WGS 반응기를 사용하였고, 비다공성 Pd/Cu 분리막을 이용하여 수소를 선택적으로 분리하여 $CO_2$를 농축하였다. 연소 전 $CO_2$ 포집에서의 활용을 고려하여 65% CO, 30 % $H_2$, 5% $CO_2$의 기체 혼합물에 대한 하이브리드 시스템의 성능을 CO 전환율과 수소 분리의 측면에서 평가하였다. 공급기체유량 1000ml/min에서 수성가스 전환반응의 운전조건으로 온도는 $200-400^{\circ}C$, 압력은 0-20bar, S/C 비는 2.5-5의 영역에서 성능을 평가하였다. 2단 수성가스전환반응기에서 CO의 전환율은 최고 99.5%이었으며, Pd/Cu 분리막을 통하여 $CO_2$를 83%로 농축시켰다.

• 한국지반신소재학회논문집
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• 제7권2호
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• pp.7-13
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• 2008

토목공사를 수행함에 있어 토목섬유가 적용된 이후 토목섬유의 손상에 대하여 많은 관심이 되어왔다. 토목용 섬유제품인 지오텍스타일은 주변 환경조건에 노출되는 고분자 재료로서 분리, 보강, 여과, 배수 등의 기능을 가지며 현재 제방공사, 해안 하천의 호안공사, 간척공사 또는 도로, 철도 노상 안정 등의 분야에 광범위하게 이용되고 있다. 본 연구는 토목섬유매트의 현장 적용시 설계방법을 분석하였고, 설계시 고려되는 인장, 파열, 꿰뚫림, 인열강도의 관계와 더불어 인장강도와 봉합강도의 상관성에 대하여 평가하였다. 또한, 토목섬유매트 적용시 유효봉합율과 시험방법의 적정성, 경제성 등이 고려된 시공방법론 등을 제시하였다.

• 대한암한의학회지
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• 제11권1호
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• pp.95-103
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• 2006

Objective: Gami-Samhwang-San, a herbal prescription for obesity treatment, is composed of seven crude herbs such as Ephedrae Herba, Scutellariae Radix, Acori Gramineri Rhizoma, Polygalae Radix, Typhae Pollen, Armeniacae Semen, Nelumbo Folium. This study was aimed to evaluate marker substances in n-butanol fraction (SH-21-B) from Gami-Samhwang-San by high performance liquid chromatography (HPLC). And we predicted inhibition activity of major compounds of Gami-Samhwang-San using Quantitative Structure Activity Relationships (QSAR) Methods: The separation was performed on a YMC J,sphere-H80 CI8(250${\times}$4.6 mm I.D) column by gradient elution with $H_3PO_4$ buffers in acetonitrile as the moblie phase at a flow-rate of 1.0ml/min. Results: HPLC was employed to determine the quantities and the qualities of several marker substances such as ephedrine, pseudoephedirne, baicalin, ${\beta}-asarone$, tenuifoliside, naringenin, amygdalin and hyperoside in the SH-21-B. Conclusion: We suggest this results could be a useful evidence for quality control of SH-21-B.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.406-410
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• 2002

A new spin filter consisting of $50{\mu}m$ (nominal pore size) depth fitters rolled on a stainless steel grid was developed, using Saccharomyces cerevisiae as a model suspension cell to evaluate the spin filter performance. In a 1.8-1 fermentor with a rotation speed of 300 rpm and perfusion rate of 4 ml/min, a cell concentration of 49 g/l and ethanol concentration of 45 g/l from 100 g/l glucose could be obtained in a perfusion culture. The major mechanisms for cell separation used by the large-pore spin filter appeared to be centrifugal force and pivotal movement of the cells in the spin filter.

• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.164-174
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• 2018

The purpose of this work designed hybrid-structured and plasma effect photocatalyst of $Ag/In_2O_3/TiO_2/HNTs$ via sol-gel and photo-reduction methods. The structures, morphologies, optical and photoelectric performances of as-prepared photocatalysts were characterized via XRD, TEM, XPS, BET, UV-vis DRS, PL and photocurrents. The photocatalytic activity was evaluated by degradation of TC. The results showed that the hybrid-structure and plasma effect can effectively cause the multi-transfer of electrons and increase the separation rate of electron and hole pairs which obtained high photocatalytic activity. The photocatalytic degradation processes reveal that $^{\bullet}O_2{^-}$ and $h^+$ are major active species.