• 한국산업융합학회 논문집
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• 제26권1호
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• pp.183-191
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• 2023

This study was conducted experimentally to investigate the surface temperature of the heat sink, the air temperature in the flow channel and the sample temperature by changing the channel number of channel type heat sink and the air flow rate when heating and cooling the bio sample. The target temperature of the sample was 15℃ or less as the minimum value and 82℃ or more as the maximum value. In this study, the channel number of the heat sink(N = 1, 2, 4, 5, 10) and the air flow rate(Q=25, 42, 54m³/min) were varied. The bio sample was replaced with water, and the volume of water is 4mL. The size of the heat sink is 80x73x150mm and the material is aluminum. When cooling the sample, the surface temperature, the air temperature and the sample temperature were highly dependent on the number of channels and the flow rate. However, when the sample is heated, the surface temperature, air temperature and sample temperature do not depend on the number of channels and the flow rate. It was found that the conditions for satisfying the minimum temperature of 15℃ or less when cooling the sample were the number of channels N≥5 and the flow rate Q≥42m³/min. When heating the sample, the conditions to satisfy the maximum temperature of 82℃ or more are the number of channels N≤5 and the air flow rate Q≤42m³/min.

• 설비공학논문집
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• 제11권1호
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• pp.10-17
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• 1999

The present work presents condensation heat transfer and pressure drop data for the flow of R-12 in flat extruded aluminum tubes with small hydraulic diameters. The tube outside dimensions are $18mm(width){\times}1.7mm(height)$. Three types of internal geometry with the same outside dimensions are tested : sample 1 (7 tube holes), sample 2 (13 tube holes) and sample 3 (7 tube holes, micro-fin). The overall heat transfer coefficient is obtained for air-to-refrigerant heat transfer, and the Wilson plot method is used to determine the heat transfer coefficient for refrigerant flow. The sample 2 and sample 3 show significantly higher performance than sample 1. The heat transfer rates for the sample 2 and sample 3 are 9% and 12% higher, respectively, than sample 1. The friction factors for the sample 2 and sample 3 are 11.9% and 2.4% higher, respectively, than sample 1.

• Food Science and Biotechnology
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• 제14권5호
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• pp.661-666
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• 2005

The specific objectives of this study were to dry yam chips using microwave vacuum drying, freeze drying and hot air drying, then to coat the dried yam chips with ascorbic acid cocrystallized sucrose, and finally to compare the quality of yam chip snack foods with respect to drying and coating characteristics. The microwave vacuum dried sample showed the highest drying rates and much less surface damage than the hot air dried one did. The shape and color of the microwave vacuum dried/coated sample were allocated between those of the freeze dried/coated sample and the hot air dried/coated sample. The freeze dried/coated sample scored excessively low in organoleptic hardness and chewiness to be suitable as a snack. The hot air dried/coated sample was too deep in color, wrinkled, excessively high in organoleptic hardness and chewiness, and excessively low in mouthfeeling. Therefore, the microwave vacuum dried/coated sample presented the best overall attributes as a snack, with respect to organoleptic characteristics, shape, color, and drying rates.

• 한국식품영양과학회지
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• 제39권9호
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• pp.1353-1358
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• 2010

폐자원으로써 버려지는 포도 가공부산물의 활용을 위한 기초연구로 본 연구에서는 포도부산물의 건조방법에 따른 일반성분, 색도, pH, 항산화성분 및 활성을 비교분석 하였다. 일반성분의 경우, 회분, 조지방, 조단백 함량은 열풍건조시료에서 더 높은 함량을 나타내었다. 색도 측정결과, L값(명도)과 a값(적색도)은 동결건조 한 시료가 더 높게 나타난 반면, b값(황색도)의 경우 열풍건조시료에서 높은 값을 나타내었다. pH는 열풍건조시료의 pH가 동결건조시료에 비해 약간 높은 값을 나타내었으나 큰 차이는 보이지 않았다. 총 폴리페놀 함량 및 안토시아닌 함량은 동결건조시료에서 더 높은 함량을 나타내었다. 항산화 활성 측정 결과 라디칼 소거능의 경우, DPPH 및 ABTS 라디칼 소거능이 열풍건조시료에 비해 동결건조시료에서 비교적 우수한 활성을 나타내었다. 반면, 환원력으로 측정한 항산화 활성의 경우, reducing power 및 FRAP 값이 동결건조시료에 비해 열풍건조시료에서 높은 활성을 나타내었으나 수치상으로 큰 차이를 보이지는 않았다. 이상의 결과에서 건조방법에 따른 항산화 성분과 항산화 활성을 비교한 결과 열풍건조시료에 비해 동결건조 시료가 더 우수한 것으로 사료된다.

• 한국조경학회지
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• 제34권2호
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• pp.36-43
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• 2006

This study was carried out to determine the ways in which drying improves and develops dredged soils which exist widely in the lowlands of Korea. Before drying there were large variations in the fundamental physico-chemical properties of dredged soils collected from different places. In the sample soils, saturated hydraulic conductivity decreased gradually with an increase in bulk density with the exception that in air-dried soils a reverse trend was observed. Also in the sample soils, the sedimentation volume and the consistency limits decreased gradually with the decrease in soil water content after the air-drying treatment. The porosity of the sample soils decreased from $0.67{\sim}0.87m^3/m^3\;to\;0.58{\sim}0.66m^3/m^3$ and the liquid-phase range decreased from $0.41{\sim}0.83m^3/m^3\;to\;0.29{\sim}0.71m^3/m^3$. The solid-phase range of sample soils increased $0.13{\sim}0.33m^3/m^3\;to\;0.24{\sim}0.37m^3/m^3$ same as above with air-drying treatment. In conclusion the air-drying treatment caused an irreversible effect on some physical properties. Accordingly, these facts indicate that the effects of air-drying treatment on these properties are considered to be resulted from irreversible changes in the structural status of the sample soils.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.202-208
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• 2008

The objectives of this study are to collect the population of each cooling system for gas and electric driven systems, and propose sample design for five cooling systems; ice storage systems, system air-conditioning system, turbo system as electric driven cooling systems, and absorption system and Gas driven Heat Pump (GHP) system as gas driven cooling systems. The sample design are carried out based on types of business, capacity, installation region and year. This study proposes criterion of the sample design for cooling systems for each energy source.

• 한국분말재료학회지
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• 제13권6호
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• pp.401-407
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• 2006

Effects of oxygen deficiency on the room temperature ferromagnetism in Fe-doped reduced $TiO_2$ have been investigated by comparing the air-annealed $Ti_{0.97}Fe_{0.03}O_2$ compound with secondly post-annealed one in vacuum ambience. The air-annealed sample showed a paramagnetic behavior at room temperature. However, when the sample was further annealed in vacuum, a strongly enhanced ferromagnetic behavior was observed at same temperature. $M{\"{o}}ssbauer$ spectra of air-annealed sample at 295K showed a single doublet of $Fe^{3+}$, suggesting that the Fe ions are paramagnetic. On the other hand, the absorption spectra after vacuum-annealing exhibited two doublets, in which one is the same component with air-annealed sample and the other is new doublet corresponding to $Fe^{2+}$ state. This result suggests that the occurrence of ferromagnetism in reduced sample may be interpreted as the contribution of unquenched orbital moment of $Fe^{2+}$ ions.

• 대한전기학회논문지
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• 제43권6호
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• pp.958-964
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• 1994

To study on the superconducting properties with cooling conditions, silver-sheathed Bi-Pb-Sr-Ca-Cu-O wires fabricated by the powder-in-tube method. The wires cooled down in the furnace, air and liquid NS12T after sintering at 840$^{\circ}C$ Critical current density of sample cooled in the furnace is 5.1${\times}$10S03TA/cmS02T and sample cooled in the air is 40A/cmS02T at 77K, zero magnetic field. The latter is very low critical current density of Bi system. 2223 high-Tc superconducting phase of sample cooled in the air was distroyed. Properties of sample cooled down in the liquid nitrogen is the same as cooled in the furnace.

• Elastomers and Composites
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• 제48권3호
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• pp.221-224
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• 2013

가시광촉매가 처리된 자동차내장재의 VOC 분석방법에 있어서 샘플백에 충진하는 질소 대신 공기를 충진하여 시험하였다. 그 결과 자동차내장재의 VOC 분석시 질소를 충진한 샘플백은 VOCs 및 폼알데히드의 저감효과가 나타나지 않았다. 그러나 질소대신 공기를 충진한 샘플백에서는 VOCs 및 폼알데히드가 현저하게 감소하였으며 자동차 내장재의 VOCs 분석시 샘플백에 질소 대신 공기를 충진하여야 가시광촉매에 의한 효과를 발휘할 수 있다는 것을 확인하였다.

• 한국산업보건학회지
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• 제33권4호
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• pp.455-463
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• 2023

Objectives: The aim of this study was to develop an air sampling and analytical method for estimating worker exposure to linear carbonate solvents and to evaluate the method. Methods: The target substances were three linear carbonates: DMC, DEC, EMC. GC/FID was used for sample analysis. Laboratory experiments were conducted to determine desorption solvents and sample capacity, and to evaluate storage stability, accuracy, and precision. Results: Coconut Shell Charcoal (CSC, 100/50 mg) was used as the air sampling media, and a desorption solvent of 5% methanol/95% dichloromethane was selected. Recommended sampling capacities were 1~11 ℓ for DMC, 1~18 ℓ for DEC, and 1~24 ℓ for EMC. The stability of three linear carbonates was demonstrated over 30 days in a refrigerator (4℃). Detection limits were determined as follows: DMC 0.26 ㎍/sample, DEC 0.24 ㎍/sample, and EMC 0.25 ㎍/sample. The total coefficient of variation was calculated as DMC 0.064, DEC 0.079, and EMC 0.07. Conclusions: This sampling and analysis method is suitable for estimating personal exposure to linear carbonates in the workplace.