• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.139-148
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• 2000

The osmotic pressure is a one of the most important factor affecting stabilization of multiple emulsion in a law hours after experiment. To understand and decrease osmotic pressure between Wl phase and W2 phase, a kinds of humectants were introduced in outer water phase. As a result, Betaine and Glucose had an excellent effect reducing osmotic pressure and NaCl made W/O/W emulsion more stable than MgSO4 did when introduced in inner water phase.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.3
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• pp.576-581
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• 2004

Foxtail Millet Yakju were treated with heat ($65^{\circ}C$/15 min) or high hydrostatic pressure ($25^{\circ}C$ (RT) and $65^{\circ}C$ (HT)/400 MPa/10 min), and stored for 64 days at l$0^{\circ}C$, $25^{\circ}C$ and 37$^{\circ}C$. Changes in microbial counts, enzyme activity and quality of Yakju during storage were measured. Total viable cells were about 10$^2$ CFU/mL, and remained almost constant during storage at l$0^{\circ}C$ and $25^{\circ}C$, while decreased significantly at 37$^{\circ}C$, and undetected after 55 days of storage in heat- and pressure(RT)-treated, but after 25 days in pressure(HT)-treated Yakju. Lactic acid bacteria and yeast in heat- and pressure-treated Yakju were not detected during storage. The relative activities of a -amylase in heat- and pressure(RT)-treated were more than 100%, while those in pressure(HT)-treated were less than 40% during storage of 64 days at l$0^{\circ}C$. However, at $25^{\circ}C$ and 37$^{\circ}C$ the relative activities in untreated and pressure(RT)-treated were decreased greatly and then reached at the point of the activities of heat- and pressure(HT)-treated. The relative activities of glucoamylase in untreated and pressure(RT)-treated were decreased as the increase of the storage temperature during storage, while those in heat- and pressure(HT)-treated increased slightly as the increase of storage period at 1$0^{\circ}C$ and $25^{\circ}C$, and had no change at 37$^{\circ}C$. pH in heat- and pressure-treated had almost no change. Turbidity and reducing sugar in heat- and pressure-treated increased as the increase of storage temperature during storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1898-1902
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• 2010

This study was designed to evaluate antioxidant activity of low-quality Codonopsis lanceolata treated by fermentation process followed by hydraulic high pressure extraction. C. lanceolata was subjected to 5,000 bar for 30 min at $25^{\circ}C$. The highest phenolics content was observed in the combined treatment of fermentation and high pressure extraction (35.11 mg/100 g), followed by high pressure extraction alone (14.78 mg/100 g) and conventional extraction (14.56 mg/100 g). The content of flavonoids followed the similar pattern as that of total phenolics, showing 280.86 mg/100 g of C. lanceolata treated by the combined fermentation with high pressure extraction whereas 193.05 mg/100 g of C. lanceolata treated by the conventional extraction. The DPPH scavenging activity was 69.32% at 0.6 mg/mL of C. lanceolata treated by the combined process, while the DPPH scavenging activities of C. lanceolata treated by high pressure extraction alone and the conventional extraction were 60.35% and 30.92%, respectively. The highest reducing power of C. lanceolata extract (1.0 mg/mL) was observed at the combined treatment (0.926), followed by high pressure extraction alone (0.881) and the conventional extraction (0.733). The combination of fermentation with high pressure extraction significantly increased the contents of phenolics and flavonoids and also enhanced the antioxidant activity. Therefore, the combined application of fermentation and high pressure extraction can be an alternative technique for the extraction of C. lanceolata. These results provide useful information for enhancing biological properties of low-quality C. lanceolata.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.848-852
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• 2011

The aim of our study was to develop drying process of apple slice. Quality characteristics of apple slices dried by hot-air and freeze drying after osmotic dehydration was investigated in different sucrose solution (20, 40, $60^{\circ}Brix$) and steeping time (2, 4, 8 hours). The weight of apple slice before and after osmotic dehydration was measured for characteristic of mass transfer. Consequently, osmotic dehydration increases weight reduction, water loss and solid gain of apple slice as the concentration of the sucrose solution and steeping time increased. Moisture contents of apples slices dried hot-air and freeze were about 3 to 7%. Hunter color L, a, b value was lower than non-treatment to osmotic dehydration of apple slice. In hot-air drying, L value decreased as the concentration of the sucrose solution and steeping time increased. The hardness increased as the concentration of the sucrose solution and steeping time increased. Contents of monosaccharide (glucose, fructose) decrease by osmotic dehydration but sucrose increased. In comparison with hot-air drying, freeze drying was high in contents of free sugar.

• Journal of Life Science
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• v.21 no.8
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• pp.1094-1099
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• 2011

Antimicrobial efficacy of high pressure (HP) can be enhanced by the application of additional hurdles. The objective of this study was to assess the enhancement in pressure lethality by tert-butylhydroquinone (TBHQ) treatment, against bacterial spores that are considered significant in the food industry. Spores of Clostridium sporogenes, Bacillus cereus and B. subtilis were prepared. Spore suspensions containing TBHQ (200 ppm, dissolved in dimethyl sulfoxide, DMSO) were pressurized at 650 or 700 MPa at 54-72$^{\circ}C$ for 5 min. Inactivation of bacterial spores resulted only with HP treatment. The population of B. subtilis spores was more inactivated by HP than those of B. cereus and C. sporogenes spores. Inactivation of C. sporogenes spores using pressure was more affected by the germinated population, compared to Bacillus spores. The inactivation of Bacillus spores increased when pressurized at 70$^{\circ}C$, compared to 54$^{\circ}C$. On the other hand, the degree of germination-induced lethality for Bacillus spores decreased at 70$^{\circ}C$. When spores were treated with a combination of DMSO-HP and TBHQ-HP, these treatments seemed to protect the spores against HP, especially at 54$^{\circ}C$. Further mechanistic studies involved in inducing germination by HP and using a subsequent sporicidal agent will be needed for a better understanding of bacterial spore inactivation.

• Korean Journal of Environment and Ecology
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• v.24 no.6
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• pp.744-750
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• 2010

This study examined the different polyphenism of larval salamander Hynobius ieechii according to two habitats, pond and stream. We collected salamander's eggs from three regions including Mountain Inwang, Surak and Gwangju. Eggs were treated by four different conditions according to predation level and habitat: high risk - which had a predation risk three times a day; low risk - which had no predation risk, pond and stream habitat. Predation risk was conducted by using chemical cue from Chinese minnows. The chemical cue treatment started from the day of collection and ended one week after the hatching. After the treatment phase, we measured the head width at the level of the eyes(HWE) and the largest head width(LHW) and snout-vent length of the each larva. We calculated the ratio of the head size by dividing HWE by LHW and made a comparison with each of the average ratio of head size according to the predation risk. The results showed that there was a significant difference in the ratio of the head size and snout-vent length according to the predation risk and habitat. From these results we found that predation risk and habitat condition can cause the different polyphenism to the larval salamander and these morphological changes could be affect their mortality.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.299-311
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• 2020

This paper analyzes the distribution of water vapor pressure and relative humidity in complex terrains by collecting weather observation data at 6 locations in the valley in Jungdae-ri, Ganjeon-myeon, Gurye-gun, Jeolla South Province and 14 locations in Akyang-myeon, Hadong-gun, Gyeongsang South Province, which form a single drainage basin in rural and mountainous regions. Previously estimated water vapor pressure used in the early warning system for agrometeorological hazard and actual water vapor pressure arrived at using the temperature and humidity that were measured at the highest density (1.5 m above ground) at every hour in the valley of Jungdae-ri between 19 December 2014 and 23 November 2015 and in the valley of Akyang between 15 August 2012 and 18 August 2013 were compared. The altitude-specific gradient of the observed water vapor pressure varied with different hours of the day and the difference in water vapor pressure between high and low altitudes increased in the night. The hourly variations in the water vapor pressure in the weather stations of the valley of Akyang with various topographic and ground conditions were caused by factors other than altitude. From the observed data of the study area, a coefficient that adj usts the variation in the water vapor pressure according to the specific difference in altitude and estimates it closer to the actual measured level was derived. Relative humidity was simulated as water vapor pressure estimated against the saturated water vapor pressure, thus, confirming that errors were further reduced using the derived coefficient than with the previous method that was used in the early warning system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.4
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• pp.443-448
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• 2010

In this paper, the changes in performance parameters, e.g., the combustor pressure, turbine power, engine mixture ratio, temperature of gas generator, and product gas, of a liquid rocket engine employing gas generator cycle with the variations in propellant-supply pressure have been described. Engine performance is numerically calculated using the 13 major system-level variables of the rocket engine. The combustor pressure and turbine power increase with an increase in the oxidizer-supply pressure and decrease with an increase in fuel-supply pressure. The lower mixture ratio of gas generator for increased fuel mass flow rate decreases the gas generator gas temperature and deteriorates the gas material properties as the turbine working fluid. The turbine power decreases with an increase in fuel-supply pressure; this results in a decrease in the main-combustor pressure, which is directly proportional to engine thrust.

• Journal of Energy Engineering
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• v.18 no.3
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• pp.203-211
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• 2009

Vapor pressure of HFC-404a and polyol ester system were measured at 56 points from 263.15 to 323.15 K and from 0 to 90 mass %polyol ester. It was found that below 273.15 K, the effect of the polyol ester on the vapor pressure was negligible up to 30 mass % polyol ester. The vapor pressure of the system significantly decreased as the mass fraction of polyol ester increased over 50 percent. Raoult's model and Flory-Huggins model were tested for data reduction. Empirical vapor pressure equations were obtained in terms of temperature and mass fraction of polyol ester.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.569-569
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• 2013

대부분의 태양전지 공정은 퍼니스와 레이저 도핑 공정이 중요한 공정 중 하나다. 퍼니스 도핑공정의 경우 저농도 도핑영역에 선택적으로 고농도 도핑영역을 형성하기가 일반적으로 어렵다. 레이저를 사용한 선택적 도핑의 경우 고가의 레이저 장비가 요구되어지며, 레이저 도핑 후 고온의 에너지로 인한 웨이퍼의 구조적 손상 문제를 야기한다. 본 연구는 저가이면서 새로운 구조의 대기압 플라즈마 제트를 개발하였고, 이를 통한 선택적 도핑에 관한 연구를 하였다. 대기압 플라즈마 제트는 Ar 가스를 주입하여 저주파(1~100 kHz) 전원을 인가하여 플라즈마를 발생시키는 구조로 제작하였다. 웨이퍼는 P-type shallow 도핑 된(120 Ohm/square) PSG (Phosphorus Silicate Glass)가 제거되지 않은 웨이퍼를 사용하였다. 대기압 플라즈마 도핑 공정 처리시간은 15 s, 30 s, 플라즈마 발생 전류는 40 mA, 70 mA로 처리하였다. 웨이퍼의 도핑프로파일은 SIMS (Secondary Ion Mass Spectroscopy)측정을 하여 분석을 진행하였으며, 도핑 후 도핑프로파일을 통하여 면저항등 전기적 특성을 파악하였다. 도펀트인 PSG (Phosphorus Silicate Glass)에 대기압 플라즈마 제트로 도핑공정을 처리한 결과 전류가 상승함에 따라, 도핑 처리시간이 길어짐에 따라서 도핑깊이가 깊어지고, 면저항이 낮아짐을 확인하였다. 대기압 플라즈마 도핑 후 웨이퍼의 구조적 손상파악을 위한 SEM (Secondary Emission Microscopy) 측정결과 도핑 전과 후 웨이퍼의 표면구조는 차이가 없음을 확인하였다.