• 한국식품영양과학회지
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• 제19권3호
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• pp.234-238
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• 1990

The effects of salt concentration immersion time in a salt solution prior to air dehydration and heating of air temperature during dehydration upon the browning reaction and pyruvic acid content of air dried garlics to a 6.5% moisture content(wet basis) were analyzed by a response surface methodology(RSM), Those values were also predicted by using a second degree polynomial regression model. Heating of air temperature was the most significant factor affecting the both browning reaction and pyruvic acid content. Salt concentration had more influence to browning reaction than immersion time whereas immersion time was more impor-tant factor than salt concentration on a retention of pyruvic acid sugested different processing conditions. While the processing conditions to minimize the browning reaction(O.D=0.009) were 0.3% of salt solution 9 min of immersion time and 5$0^{\circ}C$ of air temperature compared to control(O.D=0.022) of air dehydration at 5$0^{\circ}C$ Pyruvic acid contents were maximized(174 $\mu$mole/g garlic solid) at the 0.1% of salt solution 3 min of immersion time and 5$0^{\circ}C$ of air temperature compared to control(147 $\mu$mole/g garlic solid) of air dehydration at 5$0^{\circ}C$

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.70.2-70
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• 2002

In the thermal power plant, it is difficult to maintain strict control of the steam temperature in order to avoid thermal stress, because of variation of the heating value according to the fuel source, the time delay of changes in main steam temperature versus changes in fuel flow rate, difficulty of control on the main steam temperature control and the reheater steam temperature control system owing to the dynamic response characteristics of changes in steam temperature and the reheater steam temperature, fluctuation of inner fluid water and steam flow rates widely during load-following operation. Up to the present time, the PID controller has been used to operate this system...

• 한국식품조리과학회지
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• 제5권1호
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• pp.23-29
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• 1989

1. 밀 단백 분말을 주재료로 한 인조육을 제조할 때 가열 온도와 가열 시간이 품질 특성에 영향을 준 결과는 다음과 같다. 1) 색은 12$0^{\circ}C$로 가열한 시료가 10$0^{\circ}C$로 가열한 시료보다 L값이 낮은 수치를 나타내어 쇠고기의 색에 근접하였다. 2) 전단력, 경도, 저작성 및 보수성에서도 12$0^{\circ}C$에서 가열한 시료가 높은 수치를 나타내었고, 가열 시간에 따른 유의차는 없었으나, 12$0^{\circ}C$에서 20분간 가열한 시료가 그 수치로 볼 때 쇠고기의 측정치에 가장 근접하였다. 2. 관능 검사 1) 호두를 30% 첨가한 글루텐 인조육과 물의 양을 100%로 첨가한 시료가 색, 탄력성, 저작성에서 가장 선호도가 높았고, 가열 온도에서는 경도에서만 유의적으로 차이가 있었는데 12$0^{\circ}C$에서 20분간 가열한 글루텐 인조육이 가장 기호도가 높았다. 2) 호두와 옥수수기름의 혼합 비율을 달리하여 조제한 시료에서는 색, 다즙성에서만 유의성이 있었는데 혼합 비율은 호두 30%와 옥수수기름 10%를 첨가한 시료를 가장 선호하였다. 3) 옥수수기름과 물의 혼합 비율을 달리한 시료에서는 경도, 다즙성, 전단력에서만 유의성이 있었는데. 혼합 비율은 옥수수기름 10%, 물 100%인 시료를 대체로 선호하였다.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2001년도 가을 학술발표회 논문집
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• pp.403-404
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• 2001

In conventional heating, the heat source causes the molecules to react from the surface toward the center so that successive layers of molecules heat in turn. In the microwave heating, which is produced a volume heating effect, all molecules are set in action at the same time. And, It also evens temperature gradients without the concern of material thickness. (omitted)

• 한국식품영양학회지
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• 제26권4호
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• pp.693-699
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• 2013

본 연구는 독특한 식감과 풍미로 인하여 가공성이 낮은 C. lanceolata의 응용성을 높이기 위해 발효차를 제조하고, 열처리가 미치는 영향에 대하여 이화학 특성 및 항산화력 분석을 통하여 확인하였다. 열처리 온도 및 시간이 증가함에 따라 pH는 감소하는 경향을 보였으나, 갈색도, 탁도, 환원당, 총 폴리페놀 및 총 플라보노이드 함량은 유의한 수준으로 증가하는 경향을 보였다. 특히 200$^{\circ}C$ 15분 열처리한 시료의 총 폴리페놀 함량은 713.71mg/100ml로 대조구에 비해 약 4.5배 증가하였다. 항산화력 측정 결과, DPPH radical 소거능, FRAP 및 환원력에서 열처리 온도 및 시간이 증가함에 따라 항산화력이 뚜렷하게 증가되는 경향을 나타냈다. DPPH radical 소거능에서 $200^{\circ}C$ 15분 열처리한 시료의 경우, 85.40%로 대조구 45.17%에 비해 약 2배 이상 증가되었으며, FRAP 및 환원력 또한 $200^{\circ}C$ 15분 열처리한 경우, 대조구에 비해 약 2~3배 이상 증가하였다. 열처리에 따른 관능검사 결과, 열처리 온도 및 시간이 증가함에 따라 선호도 역시 높게 나타났다.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.271-276
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• 2015

Purpose: Quick freezing is widely used in commercial food storage. Well-known freezing techniques such as individual quick freezing require a low-temperature coolant and small cuts for the heat-transfer efficiency. However, the freezing method for bulk food resembles techniques used in the 1970s. In this study, electromagnetic (EM) heating was applied to improve the quick freezing of bulk food. Methods: During freezing, the surface of food can be rapidly cooled by an outside coolant, but the inner parts of the food cool slowly owing to the latent heat from the phase change. EM waves can directly heat the inner parts of food to prevent it from freezing until the outer parts finish their phase change and are cooled rapidly. The center temperature of garlic cloves was probed with optical thermo sensors while liquid nitrogen (LN) was sprayed. Results: When EM heating was applied, the center cooling time of the garlic cloves from freezing until $-10^{\circ}C$ was 48 s, which was approximately half the value of 85 s obtained without EM heating. For the white radish cubes, the center cooling time was also improved, from 288 to 132 s. The samples frozen by LN spray with EM heating had a closer hardness to the unfrozen samples than the samples frozen by LN only. Conclusions: The EM heating during quick freezing functions to maintain the hardness of fresh food by reducing the freezing time from 0 to $-10^{\circ}C$.

• Design & Manufacturing
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• 제17권1호
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• pp.1-5
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• 2023

In multi-material injection molding, since two or more materials with different process conditions are used, it is essential to maximize process efficiency by operating the cooling or heating system to a minimum. In this study, Liquid silicone rubber (LSR) that can be cured at a low temperature suitable for the multi-material injection molding was selected and the cure behavior according to the process conditions was analyzed through differential scanning calorimetry (DSC). Dynamic measurement results of DSC with different heating rate were obtained, and through this, the total heat of reaction when the LSR was completely cured was calculated. Isothermal measurement results of DSC were derived for 60 minutes at each temperature from 80 ℃ to 110 ℃ at 10 ℃ intervals, and the final degree of cure at each temperature was calculated based on the total heat of reaction identified from the Dynamic DSC measurement results. As the result, it was found that when the temperature is lowered, the curing start time and the time required for the curing reaction increase, but at a temperature of 90 ℃ or higher, LSR can secure a degree of cure of 80% or more. However, at 80 ℃., it was found that not only had a relatively low degree of curing of about 60%, but also significantly increased the curing start time. In addition, in the case of 110 ℃, the parameters were derived from experimental result using the Kamal kinetic model.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.59-67
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• 2012

In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.

• 공업화학
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• 제27권2호
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• pp.210-216
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• 2016

본 연구에서는 무전해 니켈 도금 시간을 달리하여 제조한 자동차 시트용 탄소섬유 발열체의 발열 및 전기적 특성에 관하여 고찰하였다. 무전해 니켈 도금된 탄소섬유의 비저항 및 비열은 4-point probe method 및 differential scanning calorimetry (DSC)를 이용하여 분석하였으며, 표면 형상 및 표면 온도는 scanning electron microscope (SEM) 및 열화상 카메라를 이용하여 관찰하였다. 실험 결과, 도금시간의 증가에 따라 니켈 도금 두께 및 표면 온도는 증가하였으며, 반면에 비열 및 비저항은 도금시간이 증가함에 따라 감소하였다. 결과적으로 무전해 니켈 도금은 자동차 시트용 탄소섬유 발열체의 저항 발열 및 전기적 특성을 크게 향상시키는 것으로 판단된다.

• 제어로봇시스템학회논문지
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• 제14권6호
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• pp.543-547
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• 2008

In the paper, we develop the ultrasonic bonding technique for LCD driver chips having small size and high pin-density. In general, the mounting technology for LCD driver ICs is a thermo-compression method utilizing the ACF (An-isotropic Conductive Film). The major drawback of the conventional approach is the long process time. It will be shown that the conventional ACF method based on thermo-compression can be remarkably enhanced by employing the ultrasonic bonding technique in terms of bonding time. The proposed approach is to apply the ultrasonic energy together with the thermo-compression methodology for the ACF bonding process. To this end, we design a bonding head that enables pre-heating, pressure and ultrasonic excitation. Through the bonding experiments mainly with LCD driver ICs, we present the procedures to select the best combination of process parameters with analysis. We investigate the effects of bonding pressure, bonding time, pre-heating temperature before bonding, and the power level of ultrasonic energy. The addition of ultrasonic excitation to the thermo-compression method reduces the pre-heating temperature and the bonding process time while keeping the quality bonding between the LCD pad and the driver IC. The proposed concept will be verified and demonstrated with experimental results.