• 한국식품영양과학회지
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• 제30권6호
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• pp.1033-1037
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• 2001

마늘의 이용성 증진에 관한 기초자료와 제품의 품질 향상에 기여하고자 마늘 oleoresin 제조과정 중의 휘발성 향기성분의 변화를 알기 위해 휘발성 향기성분을 4가지 용매로 추출하여 농축한 후, 가스크로마토그래피와 질량 분석 검출기 (mass selective detector)를 이용하여 polar(Supelcowax-$10^{TM}$)와 nonpolar capillary column(HP-5)에서 각각 분리, 동정하였다. 용매에 따른 oreoresin 추출을 보면 methanol을 사용하여 추출한 경우가 가장 peak area가 높았고 그외 acetone, methy acetate, hexane을 사용한 경우는 비슷하였다 Polar capillary column에서 총 41종이 분류되었고, pyran 및 그 유도체 물질 13종, 황화합물이 11여종, furan 및 그 유도체들이 6종, alcohol류 2종 분류되었고 그밖에도 2종의 heterocyclic compound가 각각 확인되었다. Nonpolar capillary column에서는 32종의 향기성분이 동정되었고, pyran및 그 유도체물질이 11종, 황화합물 11여 종, acid류 5종, pyran 및 그 유도체들이 3종 그밖에 eugenol 등이 나타났다. Nonpolar 보다 polar에서 휘발성성분의 다량 검출되었으며, 대부분의 휘발성 향기성분이 극성이 강한 methanol에서 잘 추출되었지만 마늘의 주요휘발성 성분인 황화합물 즉, 3,3'-thiobis 1-propene, methyl 2-propenyl disulfide, dimethyl trisulfide, di-2-propenyl -trisulfide, 2-thiophenecarboxylic acid는 비극성용매인 methyl acetate와 hexane에서 잘 추출되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.395-395
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• 2013

GaN는 LED, 태양전지, 그리고 전자소자 등에 쓰이는 물질로, 관련 연구가 활발히 진행되고 있으며, 이와 더불어 top-down방식을 활용한 소자제작 방법 또한 발달되고 있다. 하지만, 일반적으로 LED 제작에 사용되는 c-plane GaN의 경우, c축 방향으로 발생하는 분극의 영향을 받게되며, 분극은 LED내 양자우물의 밴드를 기울게 하여 전자와 홀의 재결합률을 감소시켜 낮은 내부양자효율을 야기한다. 이러한 문제를 해결하기 위해 여러 가지 방법들이 제시되었으며, 그 중에서도 a면, 혹은 m면과 같은 nonpolar면을 사용하는 GaN LED가 주목받고 있다. 본 연구에서는, top-down방식을 통해 약 $2{\mu}m$ 크기의 diameter를 갖는 micro-sized column LED를 구현하였으며, 식각 후 드러나는 semipolar면을 wet treatment를 통해 제거하여 nonpolar면을 드러나게 하였으며, 이 면에 Ni/Au를 contact하여, 전기적, 광학적 특성을 논하였다. Fig. 1은 I-V 특성 그래프이며, Fig. 2는 EL측정 결과(광학적 특성)이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.321-321
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• 2014

GaN는 LED, 태양전지, 그리고 전자소자 등에 쓰이는 물질로, 관련 연구가 활발히 진행되고 있으며, 이와 더불어 top-down방식을 활용한 소자제작 방법 또한 발달되고 있다. 하지만, top-down공정 시 발생 되는 건식 식각에 의한 소자의 손상이 발생되고, 이로 인하여 누설전류가 발생하는 등 여러 가지 문제점이 발생하고 있다. 특히, top-down에서 널리 사용하는 건식식각을 통한 GaN 식각의 경우, nonpolar 면이 아닌, semipolar 면이 드러나게 되며, 이 면은 건식 식각시 발생하는 손상을 포함하고 있다. 본 연구에서는 이러한 문제를 해결하기 위해서, 약 $2{\mu}m$ 크기의 diameter를 갖는 micro-sized column LED를 제작하고, 건식 식각 이후, KOH surface treatment를 통해 손상된 면을 제거함과 동시에 nonpolar면을 드러내는 실험을 실시하였으며, 더불어 column의 diameter를 줄이는 방법을 논하고자 한다.

• Journal of Applied Biological Chemistry
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• 제43권3호
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• pp.176-179
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• 2000

Nonpolar taxoides extracted from a large-scale cell culture of Taxus chinensis were isolated through the normal and reverse phase column chromatographies, and their compounds were identified via NMR spectroscopy. The complete separation method was systematically established and described. In dichloromethane, dissolved paclitaxel and other taxoids with hexane were precipitated during the purification of paclitaxel from the plant cell culture of T. chinensis through a large-scale process while the relatively nonpolar taxane derivatives remained dissolved in the hexane phase. 13-Deoxy baccatin III (I), baccatin VI (II), taxchinin I (III), $2{\alpha}$, $5{\alpha}$, $10{\beta}$, $14{\beta}$-tetraacetoxy-4(20), 11-taxadiene(IV), 1-deoxy baccatinVI(V), and taxayuntin C (VI) were isolated through column chromatography and identified via NMR spectroscopy. Compounds I and IV were found to the major components, aside from paclitaxel, in the plant cell culture of T. chinensis. The concentrations of I and IV were compared with the that concentration of the paclitaxel in each of plant cell culture. The possible applications of compounds I, II, IV, and V were discussed.

• 한국환경과학회지
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• 제11권6호
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• pp.605-610
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• 2002

The absorption of benzene in nonpolar solution was studied in a laboratory-scale of bubble column varying of gas flow rates and gas-to-liquid ratios. A bubble column had a 0.8∼l$\times$10$\^$-3/ m$^3$ total volume (height 1500 mm, diameter 50 mm). Solution analysis was performed by GC-FID and GC-MSD. The objectives of this research were to select the best absorption fluid and to evaluate the mass transfer characteristics under specific conditions of each absorption. The results of this research were follow as: First, the heat transfer fluid is more efficient than the other nonpolar solution in removing VOC. Second, The benzene removal efficiency improved according to an increasing rate of gas flow. Also, volumetric mass transfer rate of column can be enhanced by increasing gas flow rate. Finally, the relation of gas flow rates, liquid amount, and volumetric mass transfer coefficient was obtained as follows. K$\_$y/a: 0.5906(V$\_$g//L)$\^$0.7611/ The following correlation of mass transfer coefficient and efficiency was proposed. v= 0.06078 K$\_$y/a$\^$0.2444/.

• 한국연초학회지
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• 제4권2호
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• pp.67-73
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• 1982

Essential oil components from tobacco powder were investigated as flavouring agent. The essential oil was isolated from tobacco powder by a simple distillation /extraction method The extracted essential oil was fractionated into basic, acidic and neutral groups. And the neutral group of essential oil was separated by column chromatography into 10 fractions. Above groups and fractions were tested for tobacco aroma and smoke aroma. The neutral group except most nonpolar fraction displays good flavouring properties which make them highly suitable for improving the flavour and aroma of tobacco and tobacco smoke. The most nonpolar fraction from neutral group was carefully investigated using preparative column, thin layer and gas chromatography ailed by GC/MS coupling. The major subfraction was identified as hydrocarbons on the basis of the IR spectrum. The 58 hydrocarbon components were identified by their mass spectra and was chromatographic retention times.

• Journal of the Korean Wood Science and Technology
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• 제30권4호
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• pp.80-86
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• 2002

졸참나무 (Quercus serrata), 맹종죽 (Phyllostachys pubescens) 및 소나무 (Pinus densiflora)로부터 제조한 미정제 초액의 휘발성 성분을 고상(固相) 미량추출(solid phase microextraction; SPME)법을 이용하여 분석하였다. 이들 초액 중의 휘발성화합물 분석을 위하여 극성 (CBP 20) 및 무극성 (CBP 1) 칼람을 사용하였으며, 이로부터 총 264개의 피크를 검출하였다. 이들 성분들 중 주요 화합물은 2-butanone, acetic acid, guaiacol, phenol, 4-ethyl guaiacol, cresol류, 4-ethyl phenol, 그리고 syringol이었다. 무극성 칼람을 사용함에 의하여 7개의 성분, 즉, 1-hydroxy-2-butanone, ethisolide, furfuryl acetate, 1-(2-furanyl)-1-propane, 1,2-dimethoxybenzene, 1,2-dimethoxybenzyl alcohol, phenyl acetate를 새로이 동정할 수 있었다. 이 성분들 중 페놀류가 주성분이었으며, 휘발성 성분의 49~65%를 차지하였다. 죽초액의 경우 페놀류의 비율은 다른 두 목초액보다 낮았다. 그러나 중성화합물류 및 유기산류는 소나무 및 졸참나무로부터 제조한 목초액보다 그 비율이 더 높았다. 따라서 이들 죽초액과 목초액 간의 훈취의 차이는 목초액의 서로 다른 휘발성분의 함유량의 차이에 기인한다고 생각된다.

• Preventive Nutrition and Food Science
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• 제3권4호
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• pp.334-338
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• 1998

Kale(Brassica oleracea var. acephala) is one of Cruciferous vegetables that is closely related to the wild ancestral form of cabbabe. The ethanol extract of kale which contains the active compoundsss under Salmonella assay system was fractionated with chloroform to collect the nonpolar solvent soluble compounds, and then further fractionation was carried out by silica gel column chromatography. Among kale extracts separated by silical gel column chromatography, the fractions of 4, 5 and 6 exhibited strong antimutagenic activities. The major active compounds from the fraction were identified as chlorophyll derivatives by the analysis with HPLC-fritp-MS. The molecular weights of each chlorophyll derivatives in the sample were acquired from the peaks of positive ion atomosphere pressure chemical ionization (APCI) mas spectrometry.

• 한국환경농학회지
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• 제23권4호
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• pp.245-250
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• 2004

An analytical method was developed to determine monocrotophos residues in apple, citrus, and soil using high-performance liquid chromatography (HPLC) with ultraviolet absorption detection. Monocrotophos was extracted with acetone from apple, citrus and moist soil samples. The extract was concentrated, added with saline water, and subjected to n-hexane washing to remove nonpolar co-extractives. Dichloromethane partition was then followed to recover monocrotophos from the aqueous phase. Silica gel column chromatography was employed to further purify the extract prior to HPLC determination. Reverse-phase HPLC using an oct-adecylsilyl column was successfully applied to separate and quantitate the monocrotophos residue in sample extracts at the wavelength of 230 nm. Overall recoveries of monocrotophos from fortified samples averaged $95.3{\pm}2.1%$ (n=6), $970{\pm}0.7%$ (n=6), and $92.8{\pm}4.3%$ (n=12) for apple, citrus, and soil, respectively. The proposed method was quite reproducible and sensitive enough to replace the troublesome gas-liquid chromatographic analysis for monocrotophos residues.

• Bulletin of the Korean Chemical Society
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• 제4권4호
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• pp.183-188
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• 1983

Two major and two minor polyacetylenes were isolated from fresh white Korean ginseng roots. The petroleum ether-ethyl ether fractions containing the polyacetylene compounds were collected through solvent fractionation, partition and silica gel column chromatography. Further separation of polyacetylenic fractions was proceeded by bonded normal phase HPLC utilizing a moderately nonpolar microparticulate column. The low pressure liquid chromatography was used for the semi-preparative separation. The chemical structures of the two major polyacetylenes separated were determined by UV, IR, $^1H$ NMR, $^{13}C$ NMR, mass spectra and elemental analysis. One of them is identified to be heptadeca-1-en-4, 6-diyne-3, 9, 10-triol, a new structure, and the other is heptadeca-1, 9-dien-4, 6-diyn-3-ol, known as panaxynol.