• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.646-651
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• 2007

This study has been conducted to select the suitable refrigeration oil for a $CO_2$ refrigeration system. The oil return is one of the most important characteristics for refrigeration oils. PAG and POE oils are considered as a test fluids in this study. An evaporator model is employed to simulate the evaporator of a $CO_2$ refrigeration system. Oil return characteristics has been investigated for $CO_2$/PAG and $CO_2$/POE mixtures in the range of oil concentration 0 to 5 weight-percent and the mixture temperature range of $0^{\circ}C$ to $15^{\circ}C$. The results obtained indicate that oil return is decreased with an increase in the oil concentration and mixture temperature for both POE and PAG oils. It is also found that POE oil is seen to be superior than PAG oil in terms of oil return in an evaporator of a $CO_2$ refrigeration system.

• Applied Biological Chemistry
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• 제35권6호
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• pp.457-461
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• 1992

본 연구에서는 단백질과 기름의 농도가 분리대두단백질의 유화안정성에 미치는 영향을 연구하였다. 특히 유화안정성과 에멀젼의 기름입자크기 및 점도와의 상관관계를 구명하였으며, 또한 유화과정 중 단백질이 물과 기름 사이의 계면에 흡착하는 현상을 조사하였다. 단백질의 농도가 증가할수록 기름입자의 크기는 감소하고 점도는 증가하여 결과적으로 유화안정성이 증가하였다. 반면에 기름농도가 증가한 경우 기름입자의 크기와 점도가 모두 증가하였으며, 이 경우에는 두 요인의 상대적인 지배정도에 따라 에멀젼의 유화안정성이 결정되었다.

• 수산해양기술연구
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• 제24권1호
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• pp.36-43
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• 1988

Boilers and diesel engines have many problems because their exhaust particles, i.e., soot have lots of bad influence on environment. And it's spray and flame have fundamentally axial symmetric shape. To investigate the relationship between fuel concentration distribution of spray and soot concentration distribution as well as temperature distribution of flame, we made a axial symmetric two phase spray-flame and analyzed the structure of is. The measuring method is the principle of the light extinction method for the spray-flame and onion peeling model is applied to analyze the radial distribution of fuel and soot concentration. The temperature of flame is measured by ø 0.4mm Pt-Pt.RH 3% thermocouple. The oils for the experiments are diesel oil and 10% water emulsified diesel oil. It was found that the soot concentration becomes higher as it comes near to the center of flame, and the fuel concentration does, too. And the soot concentration level of diesel oil is generally higher than that of the 10% water emulsified fuel. The maximum flame temperature of diesel oil is 1,17$0^{\circ}C$, however, 10% water emulsified diesel oil is 1,27$0^{\circ}C$.

• 한국식품조리과학회지
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• 제26권2호
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• pp.206-213
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• 2010

In this study, the antibacterial activities of essential oil from Zanthoxylum schinifolium against four Gram-positive bacteria and six Gram-negative bacteria were investigated. The antibacterial activity of the oils was determined using the agar-well diffusion assay, MIC (minimum inhibitory concentration) and MBC (minimum bactericidal concentration). In particular, essential oil from Z. schinifolium showed higher antibacterial activity against Gram-positive bacteria than against Gram-negative bacteria. Essential oil from Z. schinifolium displayed large inhibition zones especially against Bacillus cereus (31 mm). At concentrations between 0 and $20\;{\mu}g/mL$ the oils showed an antibacterial effect against both Gram-negative and Gram-positive bacteria. The minimum inhibitory concentration (MIC) values against nine bacteria ranged from 1.25 to $5\;{\mu}g/mL$. The minimum bactericidal concentration (MBC) values against eight bacterial ranged from 2.5 to $20\;{\mu}g/mL$, except Shigella sonnei. Furthermore, our finding on the antibacterial activities of essential oils from Zanthoxylum schinifolium validated the use of this plant for medical purposes.

• Journal of Nutrition and Health
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• 제26권5호
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• pp.524-531
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• 1993

In this experiment, we investigated the changes of erythrocyte feature and Ca concentration in rat fed the diet containing different common oils in Korea for different feeding periods(4 weeks or 12 weeks), using Korea sesame oil, perilla oil, rice bran oil and mixed oil. W-3/w-6 ratio of each group was 0.001, 1.44, 0.03 and 0.112, respectively. P/S ratio of each group was 9.64, 10.49, 5.58 and 1.68, respectively. Perilla oil(w-3 rich) increased w-3/w-6 ratio of erythrocyte membrane, decreased the amount of trapped Ca and inhibited the decrease of cell volume. These results indicate that in maybe increase erythroyte fluidity and deformability, and affect erythrocyte function. In conclusion, w-3 rich perilla oil affects erythrocyte feature.

• 한국식품영양과학회지
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• 제23권5호
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• pp.736-742
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• 1994

This study was designed to observe the effects of the mixed diets of edible mushrooms and vegetables oils on the lipid component and fatty acid composition in liver of the diet induced hydpercholesterolemic rats. Ten groups of male S.D. rats were fed a basal diet supplemented with 5% of one of three mushrooms(G.I, L.e, A.j) and 10% of one of three vegetable oils (olive ,safflower perilla) for three weeks. In liver, total cholesterol concentration was significantly low in group 3 (olive oil 10 % + L. edodes 5%) and 6 (safflower oil 10 % $_2$L. edodes 5%) , triglyceride concentration was low in groups 8 (perilla oil 10 % + g. lucidum 5%) and 9 (perilla oil 10% + L. edodes 5%) and phospholipid concentration was significantly low in groups 3, 5, (safflower oil 10 % + G.lucidum 5%), 6, 7 (safflower oil 10 % + A .judae 5%) 8, 9 and 10 (perilla oil 10% + a. judae 5%). in the fatty acid composition of total lipid inliver, monounsaturated fatty acid (MUFA) concentration s were high in groups 2 (olive oil 105 + g. lucidum 5%), 3, and 4 (olive oil 10% + A. judae 5%) and all the perilla oil groups, polyunsaturated fatty acid (PUFA) and linoleic aicd concentrations were signifciantly high in all the safflower oil groups. In the fatty acid composition of liver phospholipid , PUFA concentrations were ghih but MUFA concentrations were low. In the triglyceride component, MUFA were some more than saturated fatty acid (SFA) . In the cholesteryl ester component, MUFa concentrations were significantly high. In the fatty acid composition of liver lipid components, linholeic acid was high in the PUFA and so it was major fatty acid. Eicosapentaenoic acid (EPA) of phospholipid component in liver was significantly high.

• 한국식품영양과학회지
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• 제23권1호
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• pp.23-30
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• 1994

This study was carried out to investigate the effect of the feeding mixture of linseed oil, rich in n-3 PUFA and the sunflower seed oil, rich in n-6 PUFA on the lipid metabolism in the dietary hyperlipidemic rats. After male Sprague-Dawley rats were induced hyperlipidemia by feeding the diet containing lard, butter and cholesterol for 3 weeks, then they were fed with the diet containing lard 3.0 % and butter 12.0% for control, the mixture in different proportion of both linseed oil and sunflower seed oil and antihyperlipidemic drugs for 2 weeks. Analysis of the lipid component of the serum showed following results. Concentration of total cholesterol in serum was significantly lower in the other groups except group 2 (lard 3.0 % + olive oil 12.0%) than in the control group , especially in groups 3 (cholestyramine 2.0%) and 5 (lard 3.0% + linseed oil 12.0%). HDL-C and the ratio of HDL-C to total cholesterol concentration were higher in groups 1, 3, 5 and 9 (lard 3.0% + sunflower seed oil 12.0%) , while the atherosclerotic index was low in groups3, 5. Concentrations of free cholesterol and choesteryl ester in serum were significantly lower in the other groups except group 2 than in the control group, especially lower in grop 5. Concentration of LDL was significantly higher in group 2 while it was remarkably lower in groups 3 and 5, while those of triglyceride in groups in 3 and 4 (lipraroid) were significantly higher than in the control groups. From the data on concentration of total choelsterol , HDL-cholesterol, LDL, phospholipid and triglyceride in serum, the results suggested that the feeding mixed with 3.0% lard and 12.0% linseed oil or 2.0% cholestyramine were most effective for the improvement of the serum lipids.

• 한국식품영양학회지
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• 제12권6호
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• pp.559-563
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• 1999

Essential oil of Artemisia lavandulaefolia the chrysanthemum family plant used in the chinese medicine was extracted and antibacterial and antifungal activity with many kinds of the pathogenic bacterium and fungi was experimented by it. Ataphylococcus epidermidis and Streptococcus aureus gram positive bacterium at the concentration of 200ppm and Streptococcus mutans at the concentration of 1,000ppm showed the growth injibition effect of the cell. These showed statistically significant difference(p<0.05) Zymomonas mobilis Entrecoccus faecalis gram negative bacterium at the concentration of 200ppm and Pseudomonas putida at the concentration of 400ppm showedd the growth inhibition effect of the cell)p<0.05) V. Parahaemolyticus at the concentration of 800ppm and Pseudomonas aeruginosa at the concentration of 1,000ppm showed the growth inhibition effect of the cell(p<0.05) Candida albicans and Cryptococcus neoformans yeast-type fungi showed the gorwth inhibition effect of the cell at the concentration of 200ppm(p<0.05) Altenaria mali Aspergillus nidulans and Fusarium oxysporum filamentous fungi took the growth inhibition effect of the cell at the concentration of 600ppm, 400ppm, and 100ppm. respectively.

• 설비공학논문집
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• 제11권1호
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• pp.61-72
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• 1999

The present study experimentally investigated the effect of refrigeration lubricant on the heat transfer performance in the straight sections and U-bend of a microfin tube evaporator by using R-22/mineral oil and R-407C/POE oil. The apparatus consisted of test section with U-bend, preheater, condenser, oil injection and sampling devices, magnetic pump, mass flow meter etc. The experimental parameters were oil concentration of 0 to 5 wt%, inlet quality of 0.1 to 0.5, mass flux of 219 and $400kg/m^2s$ and heat flux of 10 and $20kW/m^2$. The effects of parameters on the heat transfer coefficients were large in the order of inlet quality, mass flux and heat flux as oil concentration got increased. As oil concentration was increased, heat transfer coefficients were continuously decreased for R-22 and increased by 3% up to the concentration of 1% and then decreased for R-407C under the condition of large inlet quality, and small mass flux and heat flux. But, the heat transfer coefficients were increased up to the concentration of 3% and then decreased for both R-22 and R-407C refrigerants under the opposite conditions. The variation of enhancement factors for R-407C was under 50% of that for R-22 and the variation with respect to the positions in the test section was small. The pressure drops were increased for both R-22 and R-407C refrigerants as oil concentration was increased. The pressure drops for R-407C were smaller by the maximum of 18% than those for R-22.

• 설비공학논문집
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• 제21권1호
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• pp.16-22
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• 2009

In order to investigate $CO_2$ heat transfer coefficient and pressure drop by PAG oil concentration during $CO_2$ evaporation, the experiment on evaporation heat transfer characteristics in a mini-channels were performed. The experimental apparatus consisted of a test section, a DC power supply, a heater, a chiller, a mass flow meter, a pump and a measurement system. Experiment was conducted for various mass fluxes($300{\sim}800kg/m^{2}s$), heat fluxes($10{\sim}40kW/m^2$) saturation temperatures($-5{\sim}5^{\circ}C$), and PAG oil concentration(0, 3, 5wt%). The variation of the heat transfer coefficient was different according to the oil concentration. With the increase of the oil concentration, the evaporation heat transfer coefficient decreased and the delay of dryout by oil addition was found. Pressure drop increased with the increase of the oil concentration and heat flux, and the decrease of saturation temperature.