• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.15 no.2
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• pp.43-47
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• 2009

Respiration and quality of persimmon fruits were monitored through the storage at 0, 5, 15 and $25^{\circ}C$. Respiration rate data at different temperatures were used for determining the $O_2$ and $CO_2$ permeabilities required to maintain the optimal package atmosphere (1~3% $O_2$, 4~7% $CO_2$). The estimated gas permeabilities were then compared to those of available plastic films for examining their potential application at various temperature conditions. $O_2$ consumption and $CO_2$ production were at similar order and leveled at stable value after initial time span with higher rates measured at higher temperatures. Major quality indexes during storage were observed to be ascorbic acid content change and firmness destruction with the most significant changes at $25^{\circ}C$ Higher $O_2$ and $CO_2$ permeabilites were required at higher temperatures, and common plastic films were shown to be unable to satisfy those requirements. Films or devices of high permeation property such as silicone rubber or microporous film may be combined to increase the permeation properties satisfying the required high gas permeabilities.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.259-271
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• 2007

The purpose of this study was to investigate the dietary habits and daily intake of nutrients in college students. This survey was conducted using a self-administered questionaire. The average heights and weights were 173.5 cm and 72.3 kg of male students and 161.8 cm and 57.2 kg of female students. The average of BMI was $24.2kg/m^2$ of male and $21.9kg/m^2$ of female, and the value of male students was higher than the value of female students. The response to the daily meals was 54.6% for '$2{\sim}3$ times/week'. The regularity of mealtime was 41.7% for irregular and the frequency eating after nine was 45.7% for '5-6 times/week', respectively. The repast was 72.2% for 'overeating and little eating' and was a significant difference of male and female students (p<0.05). The eating rate was higher '$10{\sim}20min$'. As for breakfast food eaten, skipping breakfast was 23.6% for 'no/week' and female students were higher than male students (p<0.05). The frequency of snacks was 36.0% for 'nothing' of males students and 34.8% for '3-4 times/week' of female students (p<0.05). The type of snack was a significant difference of males and females students (p<0.01), and was the highest 75.0% for carbonated drinks of males and 37.5% for snacks of females. The eating due to stress solution was a significant difference of male and female students (p<0.01), and was the highest 23.0% for 'frequency' of males and 44.7% for 'sometime' of females. As for food intake of male and female students, the meat intake was 66.7% for 'everything of male and female students. The fish intake was 68.1 % for '1-2times/week'. The milk, milk products, eggs and beans were each 40.3%, 58.3%, 56.9%, 47.2% for '1-2 times/week' (p<0.05). The fat intake was 55.6% for '$1{\sim}2$ times/week'. The average consumption of energy was 58% of male and 67% of female of estimated energy requirement (EER). Their mean ratio of carbohydrate: protein: fat was 57 : 15 : 28 of all subjects. The mean intakes of vitamin C and folic acid were 70% and 51% of males and 62% and 52% of females of recommended intake (RI). The mean intakes of Ca, P, Fe and Na were 71%, 140%, 146% of males and 72%, 122%, 76% of female of RI and 273% of males and 233% of females of adequate intake (AI). Therefore, nutritional education is necessary for college students to establish physicall and mentall optimal health conditions though nutritional intervention.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.35-41
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• 2019

In order to overcome these disadvantages, the halogen light source, which was previously used as a vehicle fog light, has increased power consumption and a short lifetime, and thus, an automobile light source is gradually being replaced with an LED. However, when the vehicle LED fog light is turned on, there is a disadvantage in reducing the life of the fog lamp due to the high heat generated from the LED. The heat generated by the LED inside the fog lamp is mainly emitted by the heatsink, but most of the remaining heat is released to the outside through convection. When cooling efficiency decreases due to convection, thermal energy generates heat to lenses, reflectors, and bezels, which are the main parts of lamps, or generates high temperatures in LED, thereby shortening the life of LED fog lights. In this study, we tried to improve the heat dissipation performance by convection in addition to the heat dissipation method by heat sink, and to determine the installation location of vents that can discharge the internal air or intake the external air of LED fog lamp for vehicle. Thermal fluid analysis was performed to ensure that the optimal data were reflected in the design. The average velocity of air increased in the order of Case3 and Case2 compared to Case1, which is the existing prototype, and the increase rate of Case3 was relatively higher than that of other cases. This is because the vents installed above and below the fog lamps induce the convective phenomena generated according to the temperature difference, and the heat is efficiently discharged with the increase of the air speed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.224-232
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• 2008

The health benefits associated with tea consumption have resulted in the wide inclusion of green tea extracts in botanical dietary supplements, which are widely consumed as adjuvants for complementary and alternative medicines. Tea contains polyphenols such as catechins or flavan-3-ols including (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), as well as the alkaloid, caffeine. The contents of catechins and caffeine in green tea are considered as a standard of quality evaluation of green tea. Therefor, the purpose of this study was to investigate the most suitable HPLC condition for simultaneous determination of catechins and caffeine in green tea extracts. The efficient HPLC analytical condition of catechins and caffeine contained green tea extracts was developed. The gradient elution employed a $250\;mm\;{\times}\;4.6\;mm$ i.d. YMC-pak ODS-AM 303 column. The gradient system was used two mobile phases. A gradient elution was performed with mobile phase A, consisting of 0.1% aqueous phosphoric acid, and mobile phase B, comprising 100% MeOH, and delivered at a flow rate of 1 mL/min as follows: $0{\sim}25\;min$, 80% A; $26{\sim}50\;min$, $80{\sim}70%$ A; 51 min, 80% A. $51{\sim}55\;min$, 80% A. The UV detection wavelength was set at 280 nm. The limit of detection (LOD) for catechins and caffeine standards were under 50 ng/mL.

• Journal of Life Science
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• v.20 no.11
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• pp.1691-1696
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• 2010

Neohesperidin is a natural new nutrition sweetener, widely existing in plants of dry citrus peel, which can be derived from extraction. Since the sweetness is 1,300-1,500 times greater than that of sugar, neohesperidin are widely used in fruit juices, wines, beverages, bakeries and pharmaceutical formulations, and are particularly suitable for consumption by diabetic patients. However, the yield of extraction from citrus peel waste is very low. In this study optimal yield conditions were determinedusing response surface methodology (RSM) in order to increase the neohesperidin extraction yield. The critical factors for maximum extraction yield were selected extraction pressure ($x_1$), extraction time ($x_2$), and concentration of ethanol ($x_3$). As a result, the extraction yield was improved when the extracting pressure increased. The extraction yield also increased in a time-dependent manner. When adding ethanol as an assistance solvent to the supercritical carbon dioxide, extraction yield was increased as more ethanol concentration was added. Finally, the extraction yield of neohesperidin was improved to about 162.22% compared to ethanol extraction as a conventional method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39B no.10
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• pp.691-699
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• 2014

In order to increase network lifetime, duty-cycle MAC protocols which can reduce energy consumption caused by idle listening is proposed for WSNs. In common duty-cycle MAC protocols, each sensor node calculates its duty-cycle interval based on the current amount of residual energy. However, in WSNs with the capability of energy harvesting, existing duty-cycle intervals based on the residual energy may cause the sensor nodes which have high energy harvesting rate to suffer unnecessary sleep latency. Therefore, a duty-cycle scheduling scheme which adjust the duty-cycle interval based on both of the residual energy and the energy harvesting rate was proposed in our previous work. However, since this duty-cycle MAC protocol overlooked the performance variation according to the change of duty-cycle interval and adjusted the duty-cycle interval only linearly, the optimal duty-cycle interval could not be obtained to meet application requirements. In this paper, we propose three methods which calculate the duty-cycle interval and analyse their results. Through simulation study, we verify that network lifetime, end-to-end delay and packet delivery ratio can be improved up to 23%, 44% and 31% as compared to the existing linear duty-cycle scheduling method, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.12
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• pp.706-713
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• 2017

This study compared and analyzed the water treatment efficiency and the applicability of water treatment plant using the existing Mechanical Rapid-Mixer by introducing the Non-powered Vortex Mixer to the domestic water treatment plant. For this study, fluid flow characteristics and head loss of a Non-powered Vortex Mixer are calculated by Computational Fluid Dynamics (CFD)respectively. The head loss rate inside the mixer was 11.30% when the inflow velocity was 0.5 m/sec, 16.27% at 0.6 m/sec and 21.44% at 0.7 m/sec, the head loss rapidly increased at the optimal velocity of 0.5 m/sec. For the inflow velocity of 0.5 m/sec, the turbulent intensity at the inlet was 2.37% and at the outlet was 7.83%, so there was sufficient mixing strength for the particulate matter and the coagulant. The result of the water quality of the treatment plants with the inflow velocity of 0.38 m/sec that was operated in three years after replacing all 12 units of the existing Rapid-Mixer with the Non-powered Mixer met the standards. Hence, it is possible to reduce the energy consumption of 64,143 ~ 65,306 kWh/year since the Rapid-Mixer is replaced by the Non-powered Vortex Mixer.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.247-252
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• 2015

Aronia (Black chokeberry, Aronia melanocarpa) belonging to the Rosaceae family, is native to eastern North America. Aronia contain high levels of flavonoids, mostly anthocyanins and proanthocyanidins, which are known as condensed tannins. The dominant proanthocyanidins in aronia are (-)-epicatechin and (+)-catechin. The concentration of proanthocyanidins in aronia is higher than in other berries, however due to the astringent taste it is not desirable for consumption. Therefore, the purpose of this study is to evaluate the effect of aronia on the reduction in tannins by yeast isolated from regional Jeotgal. We isolated strains of yeast with high ${\beta}$-glucosidase activity from Jeotgal, with the MTY2 strains exhibiting a reduction in final tannin concentration according to thin layer chromatography (TLC) analysis. MTY2 was confirmed as Kazachstania servazzii using an 18S rDNA sequence and named as K. servazzii MTY2. K. servazzii MTY2 showed most significant growth when K. servazzii MTY2 was cultured in a solution of 10% (w/v) glucose, 3% (w/v) tryptone and 0.1% (w/v) sodium chloride. According to the high performance liquid chromatography (HPLC) analysis, the (+) - catechin peak is present, but (-) - epicatechin peak was reduced at culture condition added with 10% glucose in medium.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1467-1474
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• 2006

Fish-frames, which are left after obtaining fillets or muscle during fish processing, consists of useful food components, such as muscle, collagen, calcium, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). This study was carried out to prepare snack using conger eel frame (SF) for human consumption and also to elucidate food component characterization of the snack. The results of volatile basic nitrogen suggested that conger eel frame was a suitable material for preparing snack. Based on the results of sensory evaluation and costs, starch syrup was an optimal sweetener for preparing snack using conger eel frame. The starch syrup-treated SF appeared safe because the moisture content and peroxide value were below the safety limits described in the guideline of Korea Food and Drug Administration (KFDA). Starch syrup-treated SF was similar in the pattern of fatty acid composition to soybean oil, whereas EPA and DHA were detected in SF. The total content of amino acid in starch syrup-treated SF was 23.9% based on 100 g of raw material. The maj or amino acids were aspartic acid, glutamic acid, glycine and alanine. The total contents of calcium and phosphorus in starch syrup-treated SF were 4.9% and 2.8%, respectively. The Ca/P of starch syrup-treated SF was 1.9, which is a good ratio for absorption of calcium. The SF made with starch syrup was superior in EPA and DHA compositions, total amino acid, calcium and phosphorus contents to commercial snack using eel frame.

• Journal of the Korean Institute of Gas
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• v.17 no.3
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• pp.27-32
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• 2013

Natural gas liquefaction process which is operated under cryogenic condition spends large amount of energy. Most of energy in the natural gas liquefaction process is consumed by compressors. Therefore, minimizing energy consumption of compressors is an important issue in process design and operation. Among various natural gas liquefaction processes, propane pre-cooled mixed refrigerant (C3MR) process consists of mixed refrigerant system and pure refrigerant system. In this study, to find the optimal design of pure refrigerant system, pure refrigerant cycle is simulated on different number of pressure levels and the necessary energy of each design is compared. After that, the driver selection model is applied to analyse each processes, which has different number of equipments, in terms of cost. As the result, the design using many equipments spends lower energy. Using this result, this study suggests standard of process design selection by the cost term.