• Korean Journal of Pharmacognosy
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• 제20권1호
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• pp.13-20
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• 1989

In continuation of our studies on essential oils of Angelica genus(Umbelliferae), We report on the components of essential oils obtained from the root of Angelica tenuissima Nakai(藁子). Oils were obtained from the dried roots by steam distillation and fractionated by column chromatography. Each isolate or fraction was identified by GC, GC-MS and spectral analysis. Essential oils of the root of A. tenuissima(Gaoben) were found to contain $\alpha-pinene,\;camphene,\;\beta-pinene,\;myrcene,\;\alpha-phellandrene,\;\Delta-3-carene,\;p-cymene,\;limonene,\;\gamma-terpinene,\;terpinolene,\;4-vinylguauacol,\;\gamma-elemene$, one aromatic compound, three unidentified sesquiterpene alcohols, butylidenephthalide, senkyunolide and Z-ligustilide which was the most abundant compound comprising 75% of the whole oil. Also butylphthalide and hydroxybutylidenephalide were tentatively identified.

• Journal of environmental and Sanitary engineering
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• 제4권1호
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• pp.29-36
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• 1989

The purpose of this investigation was performed for chemical values related to rancidity of fat and oils extracted from deep-frying food in Seoul. The samples were collected according to kinds of fat and oils, sampling sites and food stuffs for frying. The results were as follows 1. The most used frying oils were rice bran oil $(37.0\%)$ and shortening $(29.6\%)$, followed by rapeseed oil $(14.8\%)$. 2. The chemical values related to rancidity of fat and oils extracted from deep-frying foods were the next on average. Acid value-1.42, peoxide value-39.82, dinitrophenyl hydrazine value-16.73 thiobarbituric acid value-0.263. However the highest value among oils was showed in rice bran oil and the lowest value was shortening. 3. For the classification of sampling sites, acid value and peroxide value of samples of the markets were found higher than them of environs of school and roadside, and the differences between them were significant (P> 0.01), while dinitrophenyl hydrazine value and thiobar bituric acid value were not showed the significant differences. 4. For the classification of foodstuffs for frying, there were not recognized significant differences among all kinds of them.

• Tribology and Lubricants
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• 제21권4호
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• pp.159-164
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• 2005

An experimental study was conducted to evaluate characteristic variation of diluted engine oils in which contains diesel fuels and its tribological effects on engine components. In this study, diluted engine oils with $10\%,\;15\%,\;and\;20\%$ of initial fuel content rate have been used for measuring the viscosity reduction rate, blow-by gas increment rate, main gallery pressure reduction rate, and fuel content rate in engine oils. These parameters are strongly related to the tribological characteristics of key engine components. The kinematic viscosity of engine oils in which is contained by diesel fuels from $10\%\;to\;20\%$ in oils is decreasing to approximately $54\%$ of initial diluted fuel-oil volume ratios. The experimental results show that the distillated engine oil decrease the viscosity of engine oil and its oil film stiffness, and increase the wear rate of rubbing parts of engine components. Thus we recommend that the containing volume rate of fuels in engine oils should be restricted to $3\~4\%$ for a sophisticated Diesel engine and $5\~7\%$ for a standard one.

• Food Science and Biotechnology
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• 제18권2호
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• pp.481-487
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• 2009

The compositional changes of wormwood (Artemisia princeps var. orientalis) essential oils were studied under 4 different storage conditions i.e., being exposed to air at 20 and $40^{\circ}C$. Sixty-four volatile compounds consisting of 24 terpene hydrocarbons, 18 alcohols, 11 ketones, 6 esters, 1 aldehyde, 2 hydrocarbons, and 2 oxides were identified on the basis of their mass spectra characteristics and retention indices in original wormwood essential oils. Identified compounds constituted 80.53% of the total peak area. Borneol (12.13%) was the most abundant compound, followed by $\alpha$-thujone (8.66%), T-cadinol (6.67%), and 1,8-cineole (6.21%) in original wormwood essential oils. Under the condition of $40^{\circ}C$ of temperature with the cap being opened for 3 min everyday respectively during 6 months of storage, the total amount of functional groups in essential oil determined by peak area percent were decreased by 79.45%, at most. The total level of monoterpene hydrocarbons decreased markedly in the aerobic condition and high temperatures. Whereas the total level of esters increased significantly. Wormwood essential oils were stored in experimental conditions, with the changes in the volatile compounds of essential oils being accelerated by high temperatures and contact with the atmosphere.

• Korean Journal of Plant Resources
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• 제10권4호
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• pp.314-318
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• 1997

This experiment was carried out to analyze the essential oils from different parts of Perilla frutescens spp. And to know change of the oil content by a diffenent leaf picking time. The analysis of the essential oils was done with gas chromatography(GC),and the results are as follows. Perilla frutescens spp. contained essential oils mostly in their leaves and stems, although their roots also contained the oils. It was suggested that the optimum leaf-picking time of perilla frutescens var. viridis Mak. on the basis of total essential oils was their flowering period around Aug. 24, and that of Perilla frutescens var. for acuta Kudo was Sep. 14. On the basis of perillaldegyde the optium leaf-picking time of Perilla frutescens var. viridis Mak. and Perilla frutescens var. acuta Kudo was Aug. 24. and Aug. 4. respectively.

• Proceedings of the Microbiological Society of Korea Conference
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.119-127
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• 2000

The development and performance of a competitive indirect immunoassay for the quantitative measurement of polychlorinated biphenyl compounds in insulating oils is presented. Reagent preparation and the assay characterisation, optimisation and validation steps are described. The dynamic range of the assay for Aroclors 1254 and 1260 in methanol was $50-800 {\mu}g\;ml^{-1}$ with $50\%$ signal inhibition values of 217 and $ 212 {\mu}g\;ml^{-1}$ respectively. Impending legislation in the UK is likely to decree that oils containing $ >50 {\mu}g\;ml^{-1}$ PCB be considered contaminated. Assay sensitivity increased with the degree of PCB chlorination. The assay of structurally related compounds of environmental concern yielded cross-reactivity values of under $0.6\%$. The immunoassay proved reliable for the analysis of transformer oils containing $>70{\mu}g\;ml^{-1}$ PCB, but over-estimated PCB levels in oils containing $<20{\mu}g\;ml^{-1}$ of the analyte with the oils requiring pre-treatment using either solid-phase extraction techniques or washing with KOH-ethanol/sulphuric acid to remove matrix interferents. The analytical performance of the assay was compared against a commercially available semi-quantitative immunoassay kit for PCBs in soil and water.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제61권8호
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• pp.1148-1152
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• 2012

The vegetable-based insulating oils are substitutes for mineral oils in oil-filled transformer. The important properties of vegetable insulating oil is their higher flash/fire point and biodegradability than conventional mineral oils. The large oil-filled transformer eliminate the risk of explosion and fire should the transformer fail and oil ignite owing to high flash/fire point of vegetable insulating oil. In addition, higher biodegradability of vegetable insulating oils can let the oil spill damage reduced. In this experiment, the real oil-filled transformers using mineral oil and vegetable oil have accelerated aging. After working on the 100% accelerated aging experiment were conducted comparing the transformer. The hottest-spot temperature using thermal coefficients were calculated to determin the degree of accelerated aging. As a result, apply mineral oil transformer in accordance with the accelerated aging life come to an end. In contrast, vegetable insulating oils showed the opposite characteristics. Vegetable insulating oil compared to the mineral oil are found to be an long life. As a result, the vegetable oil has a long-term stability.

• Journal of Sensor Science and Technology
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• 제22권4호
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• pp.239-243
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• 2013

Several methods are available to measure the oxidation of edible oils, such as their acid, peroxide, and anisidine values. However, these methods require large quantities of reagents and are time-consuming tasks. Therefore, a more convenient and time-saving way to measure the oxidation of edible oils is required. In this study, an edible oil-condition sensor was fabricated using single-walled nanotubes (SWNTs) made using the spray deposition method. SWNTs were dispersed in a dimethylformamide solution. The suspension was then sprayed using a spray gun onto a prefabricated Au/Ti electrode. To test the sensor, oxidized edible oils, each with a different acid value, were prepared. The SWNT sensors were immersed into these oxidized oils, and the resistance changes in the sensors were measured. We found that the conductivity of the sensors decreased as the oxidation level of the oil increased. In the case of the virgin oil, the resistance change ratio in the SWNT sensor S(%) = {[(Rf - Ri)]/Ri}(%) was more than 40% after immersion for 1 min. However, in the case of the oxidized oil, the resistance change ratio decreased to less than that of the response of the virgin oil. This result suggests that the change in the oil components induced by the oxidation process in edible oils is related to the conductivity change in the SWNT sensor.

• Proceedings of the Korea Society of Poultry Science Conference
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• 한국가금학회 2003년도 제20차 정기총회 및 학술발표회
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• pp.53-64
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• 2003

Dietary antibiotics at low, subtherapeutic levels have been shown to improve growth performance in farm animals. However, there is a trend to look for alternatives to dietary antibiotics, due to occurrence of antibiotic-resistance bacteria. The present review explored the essential oils as the possible alternative to dietary antibiotics. The antimicrobial activities of essential oils originating from plants have been well documented while their toxicological effects are seen only at very high doses. Hypocholesterolemic effect has been reported in chickens. Essential oils may stimulate the digestion process. In conclusion, dietary essential oils may be used as alternatives to antibiotics, but whether their effects on growth performance are a consequence of antimicrobial activity needs to be studied further.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제20권6호
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• pp.388-393
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• 2008

This study has been conducted to select the suitable refrigeration oil for a $CO_2$ refrigeration system. Non-hygroscopic property of refrigeration oils is one of the most important properties for refrigeration oils. PAG and POE oils are considered as test oils in this study. Transient variation of water content of PAG and POE oils was measured for 3 different vessels in the environmental conditions, such as in the range of temperature $25^{\circ}C$ to $40^{\circ}C$ and relative humidity 40% to 85%. The results obtained that water content of both POE and PAG is increased with an increase in the contact area with ambient for 3 different vessels. It is also found that water content of both POE and PAG is increased as the ambient temperature and relative humidity is increased. Non-hygroscopic property of POE oil is found to be much superior than that of PAG oil.