• 한국가스학회지
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• 제23권3호
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• pp.40-45
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• 2019

인화점은 가연성 액체 혼합물의 화재와 폭발의 위험성을 특징짓는 중요한 인화성 지표이다. 본 연구에서는 Seta flash 장치에 의해 water+formic acid 계와 water+acrylic acid 계의 인화점을 측정하였다. 측정한 인화점을 라울의 법칙과 경험식을 이용한 인화점 예측값과 비교하였다. 라울의 법칙을 이용한 예측 결과의 절대평균오차는 water+formic acid 계의 경우 $10.7^{\circ}C$ 였고, water+acrylic acid 계의 경우 $4.8^{\circ}C$ 이었다. 경험식을 이용한 예측 결과의 절대평균오차는 water+formic acid 계의 경우 $1.0^{\circ}C$ 였고, water+acrylic acid 계의 경우 $0.5^{\circ}C$ 이었다. 결과적으로 라울의 법칙에 의한 예측값에 비해 경험식에 의한 예측값이 측정값을 보다 잘 모사하였다.

• KSBB Journal
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• 제31권1호
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• pp.85-89
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• 2016

Lactic acid fermentations were conducted using water hyacinth. It is known that the pretreatment and enzyme hydrolysis process optimize the potential of water hyacinth. Lactic acid produced by using lactic acid bacteria. All cells were grown at $37^{\circ}C$ and initial pH 5.5. Lactic acid production was measured by HPLC. All Lactobacillus strains could produce lactic acid from pretreated water hyacinth. The highest lactic acid was achieved when lactic acid fermentation was carried out by L. delbrueckii for D-form and L. helveticus for L-form lactic acid production. The lactic acid concentration was 10.70 g/L by L. delbrueckii and it converted glucose in the medium to lactic acid, almost perfectly. Lactic acid production became higher when fermentation was carried out at a controlled pH 5.5. Lactic acid yield and productivity were 0.52 g/g and 0.19 g/L/h for L. helveticus, while L. delbrueckii was 0.64 g/g and 0.27 g/L/h. This study showed that water hyacinth medium could be alternative medium which can replace the complex and expensive medium for growing Lactobacillus strains in production of lactic acid.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 총회 및 춘계학술발표회
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• pp.243-245
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• 2002

Brackish water desalination using reverse osmosis(RO) membrane is more useful and economic than sea water to solve the shortage of fresh water supply because of its low total dissolved solid(TDS) contents. Silica and humic acid in brackish water make serious fouling problems and cause the decline of permeate flux and increase of operating pressure. In this study, the experiments for removal of silica and humic acid were conducted with calcite particles to prevent membrane fouling and investigated the effect of pH of feed water Adsorption of silica to calcite was higher at pH=7.5 than 9.5 and removal rate was increased according to increase of initial concentration of silica. The effect of pH on adsorption of humic acid was not significant but at low initial concentration the adsorption of humic acid was enhanced at pH 7.5. The result of this study expect to apply to brackish water desalination experiment of flat-sheet reverse osmosis membrane.

• The Korean Journal of Ecology
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• 제21권2호
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• pp.117-124
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• 1998

To clarify the effects of acid precipitates on histological damage, water status, and growth of Pinus densiflora green house experiment applyin simulated acid rain was carried out. Contact angle of water droplet on needles of P. densiflora seedlings treated with simulated acid rain of different pHs simulated acid rain was, the more rapid transpiration was. Leaf water potential after water withdrawal was also reduced rapidly in proportion to acidity of simulated acid rain. Height growth of P. densiflora seedlings treated with simulated acid rain of pH 2 decreased, while growth of seedlings treated with that of pH 3 and 4 increased comparing with that treated with normal rain of pH 5.6. pH of cultivated soil in pH 2 plot was acidified with the amount of simulated acid rain applied but that in pH 3 and 4 plots did not show any directional change. From those results, it could be interpreted that decrease of height growth in pH 2 plot was originated from multiple effects of water deficit from rapid transpiration and soil acidification. On the other hand, increased of height growth in pH 3 and 4 plots would be originated from the supply of N and S included in simulated acid rain.

• 한국식품조리과학회지
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• 제28권4호
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• pp.443-450
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• 2012

This study was investigated the effect of an oil-water fryer on quality properties of deep frying oil used for chicken. The acid and conjugated dienoic acid values of frying oil using an oil-water fryer were lower than those using a deep fat fryer, whereas the iodine value of frying oil using an oil-water fryer was higher than that using a deep fat fryer. The peroxide values of frying oil did not increase with frying number. Frying oil with an oil-water fryer had lower palmitic acid, stearic acid and oleic acid, and higher linoleic and linolenic acid contents than those with a deep fat fryer. The contents of trans-fatty acids in frying oil using a deep fat fryer and oil-water fryer after frying 110 chickens were 0.75% and 0.47%, respectively. The benzopyrene contents of frying oil using a deep fat fryer and an oil-water fryer after frying 110 chickens were 2.20 and $1.61{\mu}g/kg$, respectively.

• 한국잠사곤충학회지
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• 제33권2호
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• pp.100-102
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• 1991

제사공정의 부잠사 처리폐수에 대하여 그 성상과 추출 유지성분을 분석한 결과 1. 부잠폐수의 COD 605mgO/$\ell$ 총 용존 고형물량 2,335mg/$\ell$ 총 부유 고형물량 2,234mg/$\ell$이었다. 2. 부잠폐수의 지질에는 triglyceride가 76.8%로 가장 많이 함유되었으며 유리 지방산 12.5%와 diglyceride 5.7% free sterol 5.0% 순이었다. 3. 부잠폐수지질의 지방산 조성은 oleic acid, linolenic acid와 linoleic acid의 함유율이 64.93%로 가장 많이 함유되어 있고 palmitic acid 29.39% stearic acid 4.93%의 순이었다.

• 한국응용과학기술학회지
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• 제8권1호
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• pp.79-83
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• 1991

The extracts of Quercisemen(Quereus acutissima Carruthers seed) powder was obtained by the extraction with distilled water, water : acetonet(1:1, v/v), ethanol and ethyl ether, respectively. As a result this experiment, the antioxidative activity of each solvent extracts on linoleic acid were examined as follows: 1. Each fraction extracted by the acetone : water(1:1, v/v), water and ethanol respectively showed high antioxidative activity. 2. A fraction of the tannin extracted from the solvent, acetone, water(1:1, v/v) showed even more antioxidative activity than that of the ${\alpha}$-tocopherol or BHT. 3. Acceleration of peroxide reaction by $Fe^{++}$ and $Cu^{++}$ on the linoleic acid was strongly inhibited by adding the tannin, 4. Organic acid, such as malic acid, citiric acid and tartaric acid with the tannin were showed the synergistic effect fo the antioxidation reaction.

• 한국자원식물학회지
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• 제12권1호
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• pp.10-19
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• 1999

The water status of Pinus densiflora and P. koraiensis was observed after the treatment of simulated acid rain for every month August 1997 to March 1998. Both of the species showed increase of dry weight, water saturation deficit and epidermis transpiration after treatment of simulated acid rain (pH 3.5) for first three months. On the contrary, water content was decreased in both the species after three month of simulated acid rain treatment. The effect of simulated acid rain, however, became weaker after that and no big difference was observed after seven month of treatment. Water potential of the leaf of both species became lower than that of the control(pH 5.6) after seven month treatment of simulated acid rain. The cuticle layers of the epidermis and florins ring were damaged seriously and the size of the gap between stomata became bigger after the treatment of simulated acid rain.

• Membrane and Water Treatment
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• 제7권2호
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• pp.101-113
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• 2016

In this study, to improve the water flux of porous hydrophobic membranes, various water-soluble polymers including neutral, cationic and anionic polymers were adsorbed using 'salting-out' method. The adsorbed hydrophobic membrane surfaces were characterized mainly via the measurements of contact angles and scanning electron microscopy (SEM) images. To enhance the durability of the modified membranes, the water-soluble polymers such poly(vinyl alcohol) (PVA) were crosslinked with glutaraldehyde (GA) and found to be resistant for more than 2 months in vigorously stirred water. The water flux was much more increased when the ionic polymers used as the coating materials rather than the neutral polymer and in this case, about 70% of $0.31L/m^2{\cdot}h$ (LMH) to 0.50 LMH was increased when 300 mg/L of polyacrylamide (PAAm) was used as the coating agents. Among the cationic coating polymers such as poly(styrene sulfonic acid-co-maleic acid) (PSSA_MA), poly(acrylic acid-comaleic acid) (PAM) and poly(acrylic acid) (PAA), PSSA_MA was found to be the best in terms of contact angle and water flux. In the case of PSSA_MA, the water flux was enhanced about 80%. The low concentration of the coating solution was better to hydrophilize while the high concentration inclined to block the pores on the membrane surfaces. The best coating condition was found: (1) coating concentration 150 to 300 mg/L, (2) ionic strength 0.15, (3) coating time 20 min.

• 한국식품영양과학회지
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• 제17권2호
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• pp.172-175
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• 1988

맨드라미의 물추출 물질의 지방산과 아미노산의 조성을 조사한 결과 지방산은 모두 14종이 검출되었으며 특히 $C_{16:2}$가 되어 있었으며 필수지방산도 모두 포함되어 있었다. 미지의 물질을 확인한 결과 tricosanoic acid, lignoceric acid, cerotic acid, 1, 1'-[3-(2-cyclopentylethylidene)-1, 5-pentanediyl] biscyclopentane의 methyl ester 등을 함유하고 있었다. 아미노산은 모두 16종이 검출되었고 산성아미노산의