• Journal of the Korean Magnetics Society
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• v.5 no.6
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• pp.956-962
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• 1995

본 연구에서는 포화지방산으로 피복된 초미립 마그네타이트(Magnetite, Fe$_{3}$ $O_{4}$) 중에 nonanoic acid가 용해되어 있는 알칼리 수용액을 첨가한 후, 이들 슬러리(slurry)를 건조하여 kerosene에 분산시켜 유상자성유체를 제조하였다. Stearic acid 첨가량에 따른 분산율의 변화를 조사한 결과 stearic acid 첨가량이 증가함에 따라 분사율은 증가하였으나, 2.6 * $10^{-2}$ mol 이상에서는 분산율이 78%로 감소하 였다. Stearic acid로 피복된 마그네타이트에 의해 유상자성유체제조시 분산안정제로서 사용된 nonanoic acid 첨가량에 따른 분산율의 변화를 조사한 결과 nonanoic acid 를 첨가하지 않은 경우 분산이 일어나지 않았으나, nonanoic acid를 첨가함에 따라 분산율은 급격히 증가하였다. 포화지방산을 계면활성제로 사용하여 흡착-유기상 분산 법에 의해 유상자성유체를 제조한 결과, $C_{12}$ ~ $C_{16}$ 지방산을 사용하여 유상자성유체를 제조할 경우 20% 내외의 분산율을 나타내었다. 분산제로서 Nonanoic acid를 사용하여 유상자성유체를 제조할 경우 $C_{10}$ 지방산으로 제조한 유상자성 유체는 분산이 일어나지 않았으나, C 사슬의 길이가 증가함에 따라서 분산율은 급격히 증가하였으며 $C_{15}$ 지방산 부터는 90% 이상의 분산율을 나타내었다.

• Mycobiology
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• v.40 no.2
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• pp.145-146
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• 2012

The root of Hibiscus syriacus (Malvaceae) has been used for treatment of fungal diseases such as tinea pedis (athlete's foot). In this study, we investigated the antifungal constituent of the root of Hibiscus syriacus Ggoma, which was produced by a mutation breeding using gamma ray irradiation, and compared the antifungal activity of H. syriacus Ggoma and its parent type. According to the results, the methanolic extract of H. syriacus Ggoma exhibited four times higher antifungal activity than its parent type against Trichophyton mentagrophytes. Following purification through various column chromatographies, the antifungal substance was identified as nonanoic acid on the basis of spectroscopic analysis.

• Food Science and Preservation
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• v.7 no.3
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• pp.303-307
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• 2000

This study was conducted to investigate difference of the flavor components of barley bran, barley meju and sigumjang. The number of flavor components identified in barely meju and sigumjang was 46, 67 and 61, respectively. Among the flavor components in sigumjang, tetramethylpyrazine was the most dominant and followed by 2-furancarboxaldehyde, ethyl palmitate, 4-ethylphenol. Among the 13 kinds of flavor components commonly identified in thest samples, butanoic acid, hexanoic acid, heptanoic acid, octanoic acid and 2-pentylfuran were the most abundant in barley bran and followed by barley meju and sigumjang. In the mean while the content of nonanoic acid, 2-furancarboxaldehyde, benzenacetaldehyde and tetramethylpyrazine were the most dominant in sigumjang followed by barley meju and barley bran.

• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.723-730
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• 1994

Stable aqueous dispersion of magnetite colloid was obtained by allowing a fatty acid, such as nonanoic acid, decanoic acid and undecanoic acid, dissociated with NH4OH solution to adsorb on the monomolecular adsorption of oleate. To obtain a stable dispersion, added amounts of sodium oleate and nonanoic acid for magnetite 20g were more than 2.63$\times$10-2 mol and 0.04 mol respectively. In this colloid, good dispersions of magnetite which is sterically stabilized in aqueous system were achieved about pH 7.7. Water-based magnetic fluids using in this study were able to redisperse to water-based magnetic fluids by adding NH4OH solution to dried water-based magnetic fluid powders. Changing a magnetic fluid carrier such as kerosene was also attemped by adding kerosene to dried water-based magnetic fluid powders. In this study, we can obtain a kerosene-based magnetic fluids using drying process.

• Korean Journal of Food Science and Technology
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• v.30 no.4
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• pp.728-732
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• 1998

The purpose of this study was to identify off-flavor compounds in sea mustard and rice syrup sold in the markets. Naphthalenes such as naphthalene, 2-methylnaphthalene, 1-methylnaphthalene, 2,6-dimethylnaphthalene, 1,5-dimethylnaphthalene, 1,8-dimethylnaphthalene, 2,7-dimethylnaphthalene, 1,4,6-trimethylnaphthalene, 2,3,6-trimethylnaphthalene etc., were present in sea mustard, while free fatty acids such as butanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, dodecanoic acid, tetradecanoic acid and 2-furanmethanol, 2-furancarboxaldehyde etc. in rice syrup. The former (naphthalenes) have been supposed to be contaminents from paint of ship and the latter (free fatty acids) derived from deteriorated rice for saccharification. From the results of the samples studied, formation of their off-flavor compounds seems to be related with the condition of storage, the process of production and circulation in the markets.

• Korean Journal of Microbiology
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• v.48 no.3
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• pp.200-206
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• 2012

A bacterial strain capable of synthesizing polyhydroxyalkanoates (PHAs) with an unusual pattern of monomer units was isolated from activated sludge using the enrichment culture technique. The organism, identified as Pseudomonas aeruginosa P-5, produced polyesters consisting of 3-hydroxyvalerate and medium-chain-length (MCL) 3-hydroxyalkanoate monomer units when $C_{-odd}$ alkanoic acids such as nonanoic acid and heptanoic acid were fed as the sole carbon source. Solvent fractionation experiments using chloroform and hexane revealed that the 3-hydroxyalkanoate monomer units in these polyesters were copolymerized. The molar concentration of 3-hydroxyvalerate in the polyesters produced were significantly elevated up to 26 mol% by adding 1.0 g/L valeric acid as the cosubstrate. These copolyesters were sticky with low degrees of crystallinity. The PHA synthase genes were cloned, and the deduced amino acid sequences were determined. P. aeruginosa P-5 possessed genes encoding MCL-PHA synthases (PhaC1 and PhaC2) but lacked the short-chain-length PHA synthase gene, suggesting that the MCL-PHA synthases from P. aeruginosa P-5 are uniquely active for polymerizing (R)-3-hydroxyvaleryl-CoA as well as MCL (R)-3-hydroxyacyl-CoAs.

• Near Infrared Analysis
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• v.1 no.2
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• pp.21-27
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• 2000

Temperature-dependent changes in near-infrared (NIR) spectra have been measured for oleic acid, and nonanoic acid in the pure liquid state. Particular attention has been paid to the 5400-4800 cm$\^$-1/ region where a number of combination bands appear. The NIR spectra of oleic acid show that a band at 5303 cm$\^$-1/ increases with temperature while that at 5270 cm/sup-1/ decreases. It ha been found from their second derivative spectra that these spectral changes take place stepwisely with two break points at 30 and 53$\^{C}$, which correspond to the phase transition temperatures oleic acid reported previously. Principle component analysis (PCA) has been carried out for the NIR spectra of oleic acid in the 5400-4800 cm$\^$-1/ region measured over a temperature range of 15-80$\^{C}$. core plots of the first and second principal components (PCs) show that the NIR spectra are classified into three groups; the spectra measured in the temperature range of 15-30$\^{C}$, those in the range of 31-53$\^{C}$, and those in the range of 54-80$\^{C}$. These temperature ranges correspond to those for quasi-smectic liquid crystal, disordered liquid crystal, and isotropic liquid of oleic acid in the pure liquid state. In other words, PCA provides unambiguous evidence for the phase transitions. similar studies have been carried out for petroselinic acid and nonanoic acid in the pure liquid states, but they do not show any evidence for phase transitions.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.632-635
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• 2003

Novel poly(3-hydroxyalkanoates), PHAs, having either methoxy or ethoxy groups as the terminal hydrophilic moieties, were biosynthesized by Pseudolnons oleovorans. grown either solely with 11-alkoxyundecanoic acid or 8-alkoxyoctanoic acid, or grown with a mixture of 6-alkoxyhexanoic acid and nonanoic acid. The PHA synthesized from 11-methoxyundecanoic acid consisted of 88 mol% 3-hydroxy-7-methoxyheptanoate and 12 mol% 3-hydroxy-9-methoxynonanoate. However, the PHA produced from 11-ethoxyundecanoic acid consisted of 56 mol% 3-hydroxy-5-ethoxypentanoate and 44 mol% 3-hydroxy-7-ethoxyheptanoate. The high solubility of the PHAs in methanol and ethanol indicated that the alkoxy groups in the side chains resulted in the formation of PHAs with an enhanced hydrophilicity.

• Preventive Nutrition and Food Science
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• v.1 no.2
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• pp.203-207
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• 1996

Methanol extract of dried persimmon leaves was refractionated using hexane, chloroform, ethylacetate, n-butanol aqueous fractions. Among these chloroform fraction showed the highest inhibition rate on the mutagenicities of aflatoxin B₁(AFB₁) and 3,2' -dimethyl-4-amino-bipheny1(DMAB) in Salmonella typhimurium TA 100. Chloroform fraction was further fractionated into eight fractions by silica gel column chromatography and thin layer chromatography(TLC). The fraction 5 on TLC exhibited the highest antimutagenic activities in AFB₁and DMAB. 2,4-Decadienal, dihydro-4-methyl-2(3H)-furanone, hexanoic acid 1,4-bis(1-methy1 ethy1)benzene, heptanoic acid, phenol, octanoic acid, nonanoic acid and benzoic acid were tentatively identified from this antimutagenic fraction by GC-MS.

• Journal of the Korean Applied Science and Technology
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• v.27 no.4
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• pp.522-530
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• 2010

We developed functional synthetic lubricant for internal combustion engine oil, which would improve engine oil performance for internal combustion engine and extend engine life. We made base oil by synthesizing nonanoic acid, 1.1.1-trimethylol propane (which has good bio-degradability) and pentaerythrytol ester. We synthesized catalyst using p-toluene sulfonic acid 0.15 wt% and coloring-prevention agent hypo-phosphorus acid 0.18 wt% at 180-$190^{\circ}C$. Reaction temperature was increased at the rate of $10^{\circ}C$ for every 1 hour. When acid value reached below 3, reaction was completed. After cooling and deoxidization, we washed it by distilled water two times. After dehydration and filtering, we obtained trimethylol propane tripelargonate (TMTP) and pentaerythrytol tetrapelargonate (PETP) at yields of 96 % and 98 % respectively.