• 한국식품저장유통학회지
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• 제4권1호
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• pp.33-38
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• 1997

In order to provide informations for designing packaging and storage condition of dry jujube (Zizyphus jujuba MILLER), moisture sorption isotherm was determined for temperatures of 20, 30 and 4$0^{\circ}C$, and quality changes were evaluated as function of temperature and water activity. Dry jujube at a given water activity showed higher equilibrium moisture content for lower temperature. Moisture isothem could be fitted by GAB model equation, giving higher C value, lower m0 and relatively constant k value with increase in temperature. Ascorbic acid was lost more highly at higher temperature and water activity, and showed negligible retention for whole range of water activity and temperature studied after 141 days. Browning increased with water activity up to 0.73 at 30 and 4$0^{\circ}C$. Dry jujube of high water activity had high L value in surface color, which represent brightness of surface color. Considering quality retention in the storage, dry jujube is desired to be dried to water activity of 0.42 and be stored at temperature below 3$0^{\circ}C$

• Preventive Nutrition and Food Science
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• 제12권2호
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• pp.111-114
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• 2007

Water vapor adsorption kinetics of Inonotus mushroom powders were investigated in temperature and water activity ranges of 20 to 40$^{\circ}C$ and 0.30 to 0.81, respectively. Initial water vapor adsorption rate of mushroom powders increased with increases in temperature and water activity. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Water vapor adsorption kinetics of the mushroom powders can be well described by a simple empirical model. Temperature dependency of the reaction rate constant followed the Arrhenius relationship. The activation energy ranged from 56.86 to 91.35 kJ/mol depending on water activity. Kinetic compensation relationship was observed between k$_o$ and E$_a$ with the isokinetic temperature of 790.27 K.

• 대한건축학회논문집:구조계
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• 제34권5호
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• pp.51-58
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• 2018

The purpose of this study was to analyze the effect of seasonal change in characteristics of hygiene activity on domestic hot water energy consumption. With 16 residents of 4 households, the data about frequency of hygiene activity and water temperature was collected from February to August, 2017. The results of collected data discovered that the frequency of hygiene activity was higher especially in summer, whereas the consumption of warm water they used was higher in winter. The seasonal change in characteristics of hygiene activity was analyzed to be changed and strongly influenced by outdoor temperature. The influence of characteristics of hygiene activity on hot water consumption was analyzed. There was 13% of difference between consumption that was calculated taking characteristics of hygiene activity into account and consumption that was not. Therefore, this study suggested hygiene activity schedule, hot water profile and hot water consumption pattern, which can be utilized for improving simulation as well.

• 한국식품과학회지
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• 제22권6호
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• pp.690-695
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• 1990

커피의 저장 중 흡착에 가장 많은 영향을 미치는 인자로는 수분활성 및 온도이다. 따라서 커피의 제조공정 중 추출시 건조방법의 차이에 따른 세 종류의 제품에 대한 흡착 특성을 조사하고 수분활성, 온도 및 시간의 변화에 따른 흡착량을 측정하여 조건변수의 변화에 따른 흡착량의 변화를 예측할 수 있는 예측모델식을 수립하였다. 흡착거동은 전형적인 Sigmoid 형태를 나타냈으며 평형수분함량과 단분자층 수분함량은 동결 건조제품이 가장 높게 나타났으며 이는 건조방법에 의해 생성된 다공성구조에 기인된 것으로 사료된다. 기 발표된 여러 형태의 등온흡착곡선 모델식에 적용시켜 본 결과 Halsey 모델식의 상관계수 r값이 $0.98{\sim}0.99$로 가장 적합하였다. 또한 예측모델식은 SPSS COMPUTER PROGRAM을 이용하여 가장 오차가 적은 범위에서 수분활성, 온도 및 시간의 변화에 따른 흡착량의 변화를 예측할 수 있는 최종적인 모델식을 수립하였다.

• 한국수산과학회지
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• 제51권6호
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• pp.714-719
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• 2018

We investigated the effects of water temperature on physiological parameters in the chicken grunt Parapristipoma trilineatum. At high temperature, the aspartate aminotransferase (AST) and the alanine aminotransferase (ALT) levels were increased, suggesting that high temperature induced hepatic damage. In addition, total protein (TP) was high at high water temperatures, which were considered stressful in the breeding environment. At high water temperatures, triglycerides (TG) were low due to increased metabolic activity, which decreased the blood TG levels as TG were used as an energy source. There was no significant difference in the plasma osmolality or the blood ion concentrations with water temperature. In generally, lysozyme, a factor in innate immunity, increased with water temperature. However, lysozyme activity tended to decrease with increasing water temperature, but the difference was not significant. These results suggested that the decrease of biophylaxis at high temperature was affect the growth or survival of the population.

• 한국식품저장유통학회지
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• 제24권4호
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• pp.505-509
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• 2017

Water vapor adsorption kinetics of vacuum-dried jujube powder were investigated in temperature and relative humidity ranges of 10 to $40^{\circ}C$ and 32 to 75%, respectively. Water vapor was initially adsorbed rapidly and then reached equilibrium condition slowly. Reaction rate constant for water vapor adsorption of vacuum-dried jujube powder increased with an increase in temperature. The temperature dependency of water activity followed the Clausius-Clapeyron equation. The net isosteric heat of sorption increased with an increase in water activity. Good straight lines were obtained with plotting of $1/(m-m_0)$ vs. 1/t. It was found that water vapor adsorption kinetics of vacuum-dried jujube powder was accurately described by a simple empirical model, and temperature dependency of the reaction rate constant followed the Arrhenius-type equation. The activation energy ranged from 50.90 to 56.00 kJ/mol depending on relative humidity. Arrhenius kinetic parameters ($E_a$ and $k_0$) for water vapor adsorption by vacuum-dried jujube powder showed an effect between the parameters with the isokinetic temperature of 302.51 K. The information on water vapor adsorption kinetics of vacuum-dried jujube powder can be used to establish the optimum condition for storage and processing of jujube.

• 생명과학회지
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• 제18권2호
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• pp.187-192
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• 2008

본 연구는 수분 및 글리세를 섭취가 renin activity, 직장온도, 혈중 전해질 농도에 미치는 효과에 대하여 알아보기 위해 수분 섭취 그룹과 글리세롤 섭취 그룹으로 나누어 측정한 결과는 다음과 같다. renin activity의 경우, 안정시와 비교하여 운동 후 40분에 수분 섭취 그룹과 글리세를 섭취 그룹에서 유의한 증가를 보였다(p<0.01). Osmolality의 경우, 수분 섭취 그룹에서 차이를 보이지 않았으나, 글리세를 섭취그룹에서는 안정 시와 비교하여 운동 후 40분에 차이를 보였다(p<0.05). 직장온도의 경우, 수분 섭취 그룹과 글리세를 섭취 그룹 모두 운동 시간에 따라 점진적으로 증가하는 것을 볼 수 있었다. Na과 K의 경우, 수분 섭취 그룹에서 차이를 보이지 않았으나 글리세를 섭취 그룹에서 차이를 보였다(p<0.05). Ca과 Mg의 경우, 두 그룹 모두 그룹과 운동시기 간에 유의한 차이를 보이지 않았다.

• 한국수산과학회지
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• 제43권5호
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• pp.421-427
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• 2010

To isolate natural antihypertensive substances from edible seaweeds, we screened for and separated active compounds contained in natural Underia pinnatifida, cultural Underia pinnatifida, Laminaria japonica, Sporophylls and Agarum cribrosum. They were extracted using room temperature water, boiling water, acetone, and methanol in turn or using room temperature water, ether, acetone, methanol and boiling water in order. The in vitro antihypertensive activity was quantified as inhibitory efficacy against angiotensin-I converting enzyme (ACE), which is a factor inducing hypertension. For all of the seaweeds tested, the fractions soluble in room temperature water and in boiling water showed the strongest ACE inhibitory effect among the extracted fractions. Conversely, the methanol-extracted fractions for all of the seaweeds tested showed no antihypertensive activity. While the ether and acetone fractions had slight antihypertensive effects. The compounds in the aqueous extracts that had antihypertensive activity were presumed to be polysaccharides, such as fucoidan and alginate.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.395-395
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• 2008

Water-assisted synthesis of carbon nanotubes (CNTs) has been intensively studied in recent years, reporting that water vapor enhances the activity and lifetime of metal catalyst for the CNT growth. While most of these studies has been focused on the supergrowth of CNTs at high temperature, rarely has the similar approach been made for the CNT synthesis at low temperature. Since the metal catalyst are much less active at lower temperature, we expect that the addition of water vapor may increase the activity of catalyst more largely at lower temperature. We synthesized multi-walled CNTs at temperature as low as $360^{\circ}C$ by introducing water vapor during growth. The water addition caused CNTs to grow ~3 times faster. Moreover, the water-assisted growth prolonged the termination of CNT growth, implying the enhancement of catalyst lifetime. In general, a thinner catalyst layer is likely to produce smaller-diameter, longer CNTs. In a similar manner, the water vapor had a greater effect on the growth of CNTs for a smaller thickness of catalyst in this study. To figure out the role of process gases, CNTs were grown in the first stage and then exposed to each of process gases in the second stage. It was shown that water vapor and hydrogen did not etch CNTs while acetylene led to the additional growth of CNTs even faster in the second stage. As-grown CNTs were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), atomic force microscopy (AFM), and Raman spectroscopy.

• Journal of Ginseng Research
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• 제38권4호
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• pp.289-292
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• 2014

Ginseng leaf/stem extract produced by subcritical water extraction at high temperature ($190^{\circ}C$) posses higher cytotoxic activity against human cancer cell lines than ethanol extract. Subcritical water extraction can be a great candidate for extraction of functional substance from ginseng leaves/stems.