• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.296-301
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• 2009

The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity is increased and COP is decreased due to supercooling of water in the course of phase change from solid to liquid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N)$ of $20{\sim}25wt%$ as a low temperature latent heat storage material. The results showed that the phase change temperature and the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25wt% has the average phase change temperature of $5.8^{\circ}C$, the supercooling degree of $8.0^{\circ}C$ and the specific heat of 3.499 kJ/kgK in the cooling process. This can lead to reduction of operation time of refrigerator in low temperature latent heat storage system and efficiency improvement of refrigerator COP and overall system. Therefore, energy saving and improvement of utilization efficiency are expected.

• 한국약용작물학회지
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• 제13권1호
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• pp.52-56
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• 2005

본 연구는 수삼의 저장기간 (무저장, 2일, 6일, 8일, 10일) 및 저장온도 $(20^{\circ}C,\;34^{\circ}C,\;-10^{\circ}C)$로 구분하여 제조된 홍삼의 품질 및 이화학적 특성변화를 비교 조사하였다. 수삼의 수분함량은 저장일이 길어질수록 감소하는 경향이었다. 수삼을 10일동안의 단기간 저장온도는 $34^{\circ}C$의 냉장저장이 적합하다고 생각한다. 전질소 함량은 저장일 10일로 갈수록 무저장구에 비해 다소 증가하는 경향이었다. 저장온도별로는 실온, 냉동, 냉장저장 순으로 무저장구보다 전질소 함량이 증가함을 보였다. 각각의 저장구별 페놀성 화합물의 함량은 무저장구에 비하여 저장기간이 길수록 증가하는 경향이었다. 저장 온도별로는 냉장 저장구가 실온, 냉동 저장구에 비하여 다소 페놀성 화합물의 함량이 높았다. 저장조건별 홍삼의 사포닌 Rf 에 대한 8종의 $ginsenoside\;Rb_1,\;Rb_2,\;Rc,\;Rd,\;Re,\;$Rg_3,\;Rg_1,\;Rg_2$의 상대적 함량 (%)비 변화를 분석한 결과, 각각 저장조건에서 Rf 대한 $Rb_1,\;Rg_1$의 상대적 함량비가 저장기간이 늘어날수록 감소하는 경향이었다. 기타 ginsenoside 함량변화는 시료간의 차이에서 나타난 것으로 판단되며 저장조건에 따른 변화 경향은 뚜렷하지 않았다. 관능적 성질에서 각각 저장구별로 홍삼의 품질, 맛과 향을 종합적으로 평가하여 볼 때, $34^{\circ}C$에서 냉장저장 운반하는 것이 홍삼 향미의 안정적 유지에 가장 적합한 것으로 평가되었다.

• Food Science and Biotechnology
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• 제18권5호
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• pp.1091-1095
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• 2009

The aim of this study investigated the fluctuations of 3 characters from 3 ecotypes [early ripening (ER), middle ripening (MR), and late ripening (LR)] of 20 Korean brown rice cultivars in different storage systems [time: 12 and 24 weeks, temperature: low ($10^{\circ}C$) and room ($25^{\circ}C$)]. With increase of storage time and temperature, lipoxygenase activity, and fat acidity increased, whereas germination rate was reduced. ER cultivars exhibited the highest lipoxygenase activity of $35.49{\pm}2.46$ unit/mg protein during 24 weeks storage at $25^{\circ}C$, followed by LR ($32.73{\pm}1.33$) and MR ($32.66{\pm}1.62$) cultivars. The amounts of fat acidity also were observed by the same order (ER: $20.40{\pm}2.12$>LR: $19.68{\pm}1.86$>MR: $19.64{\pm}1.35$ mg KOH/100 g). Germination rate slightly decreased with increase of time and temperature (MR>LR>ER), but MR and LR cultivars showed the most significant changes (ER: $60.90{\pm}23.47%$, MR: $32.66{\pm}13.95%$, and LR: $32.53{\pm}5.87%$). On the basis of above results, MR cultivars were evaluated the highest quality, because high lipoxygenase activity, high fat acidity, and low germination rate have deteriorated in quality and generated off-odor. Thus, MR cultivars might be very important sources in food processing and stored dietary supplement aspects.

• 보존과학회지
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• 제37권5호
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• pp.440-450
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• 2021

수장고 및 전시 공간의 종합적 유해생물 관리를 위하여 실시간 온습도 센서 및 모듈을 이용한 환경 데이터 수집, 실내 부유 진균류 농도 및 곤충 유입 자료의 데이터 시각화를 부여 정림사지 박물관 유물 공간을 대상으로 실시하였다. 실시간 온습도 모니터링 시스템은 30분 단위로 측정 데이터를 수집하였으며 연동 애플리케이션을 통해 측정 데이터를 실시간으로 확인 가능하도록 하였다. 또한 측정된 온습도 데이터가 미리 설정한 범위를 초과하였을 경우, 푸시 알림을 담당자의 단말기로 전송하여 현황 정보를 제공함으로써 상시적 관리 체계를 구축하였다. 이를 통해 8월 중 유물 권장 온도 범위를 초과한 상황의 즉각적인 인지 및 조치가 가능하였다. 수장고 내부 공간에 따른 시기별 부유진균류 농도 데이터를 국립문화재연구소에서 제시한 생물학적 유해환경요인 권고기준(안) 기준으로 범례화하여 시각화한 결과, 수장고 1층과 2층 유물 공간 모두 위험 기준인 80 C.F.U./m³ 이하의 부유 진균류 농도가 유지되는 것이 확인되었다. 또한 곤충 유입 조사 결과, 수장고 내부에는 곤충이 포획되지 않았으며, 전시공간의 경우, 딱정그리마, 알락귀뚜라미, 알락꼽등이 등의 곤충이 포획되었다. 이를 바탕으로 구역별 포획 곤충의 개체 밀도에 따른 시각화를 실시한 결과, 곤충의 주요 유입 경로가 외부 출입구 및 화장실 구역임을 확인할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.225.1-225.1
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• 2010

Within recent years attention has been focused on the method of hydrogen storage using metal hydride reactor due to its high energy density, durability, safety and low operating pressure. In this paper, a numerical study is carried out to investigate the coupled heat and mass transfer process for absorption in a cylindrical metal hydride hydrogen storage reactor using a newly developed model. The simulation results demonstrate the evolution of temperature, equilibrium pressure, H/M atomic ratio and velocity distribution as time goes by. Initially, hydrogen is absorbed earlier from near the wall which sets the cooling boundary condition owing to that absorption process is exothermic reaction. Temperature increases rapidly in entire region at the beginning stage due to the initial low temperature and enough metal surface for hydrogen absorption. As time goes by, temperature decreases slowly from the wall region due to the better heat removal. Equilibrium pressure distribution appears similarly with temperature distribution for reasons of the function of temperature. This work provides a detailed insight into the mechanism and corresponding physicochemical phenomena in the reactor during the hydrogen absorption process.

• 방사선산업학회지
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• 제9권2호
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• pp.57-62
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• 2015

In this study, we fabricated effect of storage conditions on graft of polypropylene (PP) non-woven fabric induced by electron beam. The electron beam irradiations on PP non-woven fabric were carried out over a range of irradiation doses from 25 to 100 kGy to make free radicals on fabric surface. The radical measurement was established by electron spin resonance (ESR) for confirming the changes of the alkyl radical and peroxy radical according to effect of storage time, storage temperature and atmosphere. It was observed that the free radicals were increased with irradiation dose and decreased with storage time due to the continuous oxidation. However, the radical extinction was significantly delayed due to reduced mobility of radicals at extremely low temperature. The degree of graft based on the analysis of ESR was investigated. The conditions of graft reaction were set at a temperature: $60^{\circ}C$, reaction time: 6 hours and styrene monomer concentration: 20 wt%.

• Preventive Nutrition and Food Science
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• 제17권1호
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• pp.46-52
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• 2012

This study was performed to investigate the effects of pre-treatment and storage temperature and periods on the quality characteristics of ginger paste. The pH of the ginger paste remained constant during room temperature storage but increased with prolonged refrigerated storage periods. During five months of frozen storage, regardless of pre-treatment, the pH of most of the samples decreased slightly and then remained constant. In the color value of ginger paste stored at room temperature, the samples with and without chemical additives changed in color more prominently than fermented or pasteurized samples. Intriguingly, the color value for samples containing chemical additives changed more dramatically when stored under refrigerated conditions. However, the L, a, and b values of samples stored under frozen storage conditions did not change even after ten months. Most of the samples contained glucose and fructose, except for the fermented samples. The free sugar content of samples slowly decreased with increasing storage periods, while the organic acid content generally decreased also, regardless of sample type. Depending on pre-treatment and storage temperature, the gingerol content of the samples was either retained or decreased with prolonged storage time.

• 한국식품위생안전성학회지
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• 제12권2호
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• pp.107-110
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• 1997

To examine the effects of residual phosphorus content on color reversion and storage stability of corn germ oil, the changes of Lovibond total color and stability of oxidation were determined according to the different storage periods at room and incubating temperature, respectively. The residual phosphorus content and storage temperature had the synergistic effect on color reversion during short time storage. The extent of color change was the greatest when oils were stored for 1.0∼1.5 years at room temperature and thereafter gradually tended to reverse color reversion. It is supposed that the double bonds of carotenoids in oils were oxidized and then turned to the volatiles such as epoxide, ionone, and etc. In contrast, the residual phosphorus content increased oxidation stability of oils. The residual phosphorus content was closely correlated with the color reversion and storage stability, respectively.

• 한국태양에너지학회 논문집
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• 제27권4호
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• pp.43-49
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• 2007

This study is conducted to improve the efficiency of a thermal storage tank. The thermal storage tank was designed to store heat energy that obtained from the solar or the others heat sources. However, it has difficulties in storing heat with nonuniform temperature through the entire tank with respect to the vertical direction, This study is focused on the thermal stratification to improve thermal comfort for the resident in house. To enhance temperature stratification of the tank, a distributor was designed and installed in the middle of the storage tank vertically. The vertically designed distributor could supply the return water with stratified temperature in the storage tank with respect to the height. The water velocity from the distributor hole is the same with the other outlet in the distributor. However, gravity effect on the flow in the storage tank is much higher than that of the velocity effect due to that Froude Number is less than 1. During the heat charging process in the storage tank, temperature maintained with little difference with respect to the height. However the charging process takes long time to get a effective temperature for the heating or hot water supply because of all of water in the storage tank needs to be heated.

• 자원환경지질
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• 제50권2호
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• pp.159-170
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• 2017

다공성 구조의 장석과 주택 시방기준으로 제작된 바닥 축열층 모르타르의 열적 특성과 소비전력을 비교하였다. 실험을 위해 온수관이 설치된 2개의 실대형 모형을 제작하였다. 자외선 열화상 온도와 온도센서를 이용하여 가열과 냉각과정에서 축열층의 온도변화를 모니터링하였다. 시험동의 축열층은 $20-30^{\circ}C$ 구간의 온도 범위의 가열조건에서 $2-3.5^{\circ}C$ 높은 온도를 보였고 목표 온도에 도달하는 시간이 단축되었다. 온수관에서 멀어질수록 $4-4.8^{\circ}C$ 이상의 차이를 보였고 이는 장석 기반의 모르타르 축열층이 열적 평형에 빨리 도달하는 것을 지시한다. 가열 온도 $30^{\circ}C$를 기준으로 산정한 소비전력은 2.2배 차이를 보였고 단계별 온도 상승에서 소비전력은 66% 절감되었다. 냉각에서 시험동의 표면온도는 지속해서 $2^{\circ}C$ 이상 높았고 축열로 인해 보일러의 재가동 시간이 연장되는 것을 고려하면 에너지 효율은 더 증가할 것이다.