• 한국식품저장유통학회지
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• 제16권6호
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• pp.861-868
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• 2009

본 연구는 빙점 강하제를 첨가한 다진 홍고추의 활용 가능성을 평가하기 위해 김치에 첨가하여 특성변화를 살펴보았다. 빙점강하제로는 NaCl, glucose, pectin, ascorbic acid를 사용하였으며 비율을 달리하여 다진 홍고추에 첨가한 후 김치를 제조하여 관능평가를 한 결과 관능에 가장 큰 영향을 미치는 요인은 NaCl 함량임을 확인하였다. 이에 glucose, pectin, ascorbic acid 함량은 각각 5%, 1% 및 0.5%로 정하였으며 NaCl 함량을 3, 5 및 10%로 달리하였다. 그 결과 대조구와 3, 5, 10% NaCl 첨가한 처리구의 염도는 각각 1.92, 2.28, 2.47 및 3.10%로 NaCl 첨가에 의한 차이를 나타내었다. pH는 시료들 간의 유의적인 차이는 나타나지 않았으며 산도는 제조직후를 제외하고 NaCl 함량이 높을수록 낮은 수준을 나타내었다. 환원당은 저장 20일째 대조구의 경우 70% 수준 감소한 반면 NaCl 첨가구는 45~55% 감소하여 NaCl 함량이 높을수록 환원당 함량의 감소률이 적었다. 초기 vitamin C의 함량은 대조구는 37.22 mg%였으며 ascorbic acid를 첨가한 처리구들은 125.88-145.23 mg%로 2배 이상 차이를 보였으며 NaCl 첨가구의 감소율이 대조구에 비해 적었다. 젖산균수도 NaCl 함량이 높을수록 적은 경향을 보였다. 관능평가 결과 외관, 조직감은 숙성 20일째까지 유의적인 차이를 보이지 않았다. 맛과 전반적인 기호도는 숙성기간동안 3% NaCl 처리구를 가장 선호하는 것으로 나타났다.

• 융복합기술연구소 논문집
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• 제6권2호
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• pp.25-28
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• 2016

Recently, due to the climate change by global warming, the amount of snow has increased. The situations were demanded to use many snow removal materials. The snow removal materials that used in Korea were solid chloride deicing material. That is calcium chloride($CaCl_2$) and sodium chloride(NaCl). Solid chloride baesd snow removal materials have various property, for example good freezing point depression, deliquescence and economical solvents. However, there are problems such as water pollution, high corrosiveness and ecocide. For such reason, development of eco-friendly deicer was required obligatorily. This study investigated development situation of eco-friendly deicer materials.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1559-1562
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• 2009

The influence of hot pressing on the pore structures of Nafion membranes was investigated by observing the Nafion before and after hot pressing with $^1H$ nuclear magnetic resonance (NMR) spectroscopy. The freezing point depression and chemical shift data of water in the Nafion indicated the presence of two different pore size ranges in Nafion. Hot pressing mainly reduced the sizes and number of the big pores. The reduction of water uptake and proton conductivity after hot pressing was explained by this variation of pore size and number. We demonstrated the potential application of chemical shift data and NMR cryoporometry experiments to measure the relative pore sizes, on a nano scale, and numbers.

• Animal cells and systems
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• 제3권1호
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• pp.47-52
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• 1999

Change of proteins was confirmed during low temperature acclimation of overwintering larva, and some biochemical characteristics of the induced antifreeze protein-1 (AFP-1) were investigated in Protaetia brevitarsis. As the freezing point depression by the action of induced AFPs, a considerable thermal hysteresis was observed in the haemolymph and in partially purified proteins. AFP-1 was purified from the cold acclimation larvae by ammonium sulfate precipitation ion exchange chromatography, gel permeation chromatography, and electroelution. The purified AFP-1 was determined to be a glycoprotein (approximately 320 kDa, pl 5.8) composed of a single type of subunit (80 kDa). The high contents of hydrophilic amino acids (Asp, Glu, Lys, Asn, Gln, Arg, Ser, Thr) were also confirmed, showing similarity with antifreeze proteins from other insects.

• 한국에너지공학회:학술대회논문집
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• 한국에너지공학회 2006년도 에너지.가스.기후변화학회 연합춘계학술대회 및 특별심포지움
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• pp.317-324
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• 2006

This study aims to find out cooling characteristics of TMA(Tri-Methyl-Amine, ($CH_{3})_{3}N$) 25wt%-clathrate compound with ethanol($CH_{3}CH_{2}OH$) such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at $-6{\sim}-8^{\circ}C$, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as $3.8^{\circ}C$ according to cooling source temperature in case that 0.5w% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is $0.9^{\circ}C $ and minimum supercooling is $0.8,\;0.7^{\circ}C$ according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is $3.013{\sim}3.048\;kJ/kgK$ according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol. This can lead to shorten refrigerator operation time of low temperature thermal storage system and improve COP of refrigerator and efficiency of overall system. Therefore energy can be saved and efficiency can be improved much more.

• 한국자동차공학회논문집
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• 제15권1호
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• pp.23-28
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• 2007

This study aims to find out cooling characteristics of TMA(Tri-Methyl-Amine, $(CH_3)_3N$) 25wt%-water clathrate compound with ethanol($CH_3CH_2OH$) such as supercooling, phase change temperature and specific heat. For this purpose, ethanol is added as per weight concentration and cooling experiment is performed at $-6{\sim}-8^{\circ}C$, cooling heat source temperature, and it leads the following result. (1) Phase change temperature is decreased due to freezing point depression phenomenon. Especially, it is minimized as $3.8^{\circ}C$ according to cooling source temperature in case that 0.5wt% of ethanol is added. (2) If 0.5wt% of ethanol is added, average supercooling degree is $0.9^{\circ}C$ and minimum supercooling is 0.8, $0.7^{\circ}C$ according to cooling heat source temperature. The restraint effect of supercooling is shown. (3) Specific heat shows tendency to decrease if ethanol is added. It is $3.013{\sim}3.048\;kcal/kg^{\circ}C$ according to cooling heat source temperature if 0.5wt% of ethanol is added. Phase change temperature higher than that of water and inhibitory effect against supercooling can be confirmed through experimental study on cooling characteristics of TMA 25wt%-water clathrate compound by adding additive, ethanol. This can lead to shorten refrigerator operation time of low temperature latent heat storage system and improve COP of refrigerator and efficiency of overall system. Therefore energy can be saved and efficiency can be improved much more.

• Childhood Kidney Diseases
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• 제4권1호
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• pp.6-10
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• 2000

목 적 : 출생 후 며칠간의 신생아의 creatinine수치는 모체의 영향을 받으므로 소변의 creatinine을 상수로 용질 배설 측정을 하는 것은 의미가 없을 수도 있다는 보고가 있어, 저자들은 신생아에서 일정한 간격으로 측정된 소변 creatinine이 차이가 있는가에 대하여 연구를 시행하게 되었다. 방 법 : 1998년 7월부터 8월까지 출생한 건강한 신생아를 대상으로 하여 두 번의 소변을 측정하였으며, 대조군으로는 그 기간 동안 입원한 소아과 병동의 환아를 대상으로 하였다. 신생아군은 49명이고 대조군은 33명이었으며, 신생아군의 첫 소변은 출생 첫날 시행하였고 비교군의 첫 소변시 나이는 $5.7{\pm}4.3$세였다. 신생아군과 대조군에서 처음과 두 번째 소변간의 간격은 2-3일이었다. 통계분석은 sigmastat 2.0을 사용하여 단순 선형 회귀 분석, t-test, paired t-test를 이용하였다. 결 과 : Creatinine mg/dL(Mean${\pm}$SD)은 첫 소변, 두 번째 소변에서 각각 신생아군은 $32.5{\pm}29,\;29.2{\pm}23$이고 대조군은 $57.7{\pm}51,\;58.8{\pm}51$으로 두 군 모두 첫 소변과 두 번째 소변의 소변 creatinine치는 차이가 없으며, 두 군간의 평균치의 비교분석은 유의한 차이를 보였다(P<0.01). 첫 소변과 두 번째 소변간의 creatinine평균치의 상관성에서 신생아군은 r=0.504(P<0.001)이고 대조군은 r=0.631(P<0.001)이었으며, creatinine/osmolality로 보정 후에도 각각 상관계수 0.506(P<0.001), 0.386(P<0.001)으로 유의한 상관관계를 보였다. 결 론 :신생아의 첫 소변과 두 번째 소변에서 creatinine의 비교분석에서는 유의한 차이가 없었으며 따라서 신생아에서도 용질배설 측정시 creatinine을 기준치로 사용할 수 있을 것으로 사료된다.