• Applied Chemistry for Engineering
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• v.24 no.6
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• pp.621-627
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• 2013

In order to apply eco-friendly poly(propylene carbonate) (PPC) into barrier packaging materials, six different PPC/exfoliated graphite (EFG) nanocomposite films with different EFG were successfully prepared by a solution blending method. Their water sorption behavior was gravimetrically investigated as a function of the EFG content and interpreted with respect to their chemical structure and morphology. The water sorption isotherms were reasonably well fitted by Fickian diffusion model, regardless of morphological heterogeneities. With increasing the EFG content, the diffusion coefficient and water uptake decreased from $12.5{\times}10^{-10}cm^2sec^{-1}$ to $7.2{\times}10^{-10}cm^2sec^{-1}$ and from 8.9 wt% to 4.2 wt%, respectively, which indicates that the moisture resistance capacity of PPC was greatly enhanced by incorporating EFG into PPC. The enhanced water barrier property of the PPC/EFG nanocomposite films with the high aspect ratio EFG makes them potential candidates for versatile packaging applications. However, to maximize the performance of the nanocomposite films, further researches are required to increase the compatibility of EFG in the PPC matrix.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.624-629
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• 2012

To capture and recover carbon dioxide ($CO_2$), we impregnated honeycomb made of ceramic paper with $K_2CO_3$ and its absorption characteristics of $CO_2$ were investigated. The absorption amount of $CO_2$ on the honeycomb absorbent impregnated with $K_2CO_3$ was 13.8 wt% at a constant temperature ($70^{\circ}C$) and relative humidity (66%) condition. Because the absorption amount of $CO_2$ achieved almost the same loading ratio of $K_2CO_3$ (17.6 wt%), the absorption reaction of $CO_2$ by $K_2CO_3$ on the honeycomb absorbent seems to be going smoothly. In addition, $CO_2$ absorption breakthrough characteristics of the honeycomb absorbent were analyzed at the temperature range of $50{\sim}80^{\circ}C$, and the water vapor was fed to an absorption column before the feeding of $CO_2$ or simultaneously with $CO_2$. As a result, the absorption capacity of $CO_2$ was more enhanced using the water vapor supplying before $CO_2$ than that of simultaneous supplying. It was confirmed by temperature programmed desorption analysis that the $KHCO_3$ produced by the absorption reaction of $K_2CO_3$ and $CO_2$ is regenerated by the desorption of $CO_2$ at a temperature of about $128^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.1
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• pp.14-20
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• 1986

Responses of three different crops to soil water status were investigated in a Bonryang Sandy loam for 5 years. The changes in soil water potential, water and nutrient uptakes, growth pattern, water use efficiency and yield were analyzed under different irrigation conditions. Chinses cabbage showed more water stress than radish and red pepper in the non-irrigatedcultivation. The higher soil water potential, the more nutrient and water uptake, and evapotranspiration were observed. Water use efficiency was increased with the increase of evapotranspiration up to the optimum amount, whereas the efficiency was decreased when evapotranspiration was exceeded the optimum lebel. Little growth of chinese cabbage was observed when the soil water potential was lower than -1.7 bar at 20-30 cm depth in spring cultivation. The optimum soil water potential for irrigation was -0.2 bar, -0.5 bar and -0.2 - -0.5 bar for chinese cabbage, radish and red pepper, respectively. Optimum irrigation markedly improved the crop quality and yield in comparison to non irrigation condition.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.278-278
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• 2021

가뭄이 장기간 지속되어 농업적 가뭄 상태가 되면 토양의 수분이 마르기 시작하면서, 식생의 생장활동이 방해되고, 이는 식생의 광합성 활동까지 영향을 미친다. 광합성을 통해 대기 중의 이산화탄소가 흡수되고 산소 발생이 증가하는데, 광합성이 활발하지 못하면 상대적으로 대기 중의 이산화탄소 농도가 증가한다. 본 연구에서는 이러한 토양수분, 식생활동과 대기 중 이산화탄소의 농도의 관계를 다중분광센서인 MODerate resolution Imaging Spectroradiometer (MODIS) 산출물을 이용하여 분석하였다. 기존 토양수분의 경우, 마이크로파 센서를 통해 산출된 값을 활용했지만, 이는 상대적으로 공간 해상도가 조악하다는 단점을 갖고 있어서 면적이 작은 연구지역을 분석할 때에는 한계점을 갖고 있다. 이러한 문제를 해결하기 위하여 상대적으로 고해상도인 광학센서를 이용한 토양수분 산정 방법을 적용하였다. 또한, MODIS 총 일차생산량 (Gross Primary Productivity, GPP) 산출물을 이용하여 식생 호흡량과의 관계식을 통해 이산화탄소 플럭스를 계산하였다. 원격탐사 기반의 토양수분, 식생지수, 이산화탄소 플럭스를 한국에서 발생한 가뭄 기간 중, 2014년과 2015년도에 대하여 지점 관측자료인 플럭스 타워에서 제공되는 값과 비교 분석하였다. 분석한 결과 토양수분, 식생 지수, 탄소플럭스는 순차적으로 지연시간을 두고 상관성이 발생함을 확인하였다. 토양수분과 식생 지수 사이에는 1개월, 식생지수와 탄소플럭스는 0.5개월의 지연시간 후에 가장 높은 상관성을 보였다.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.853-859
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• 2010

This study was performed to evaluate the physicochemical and sensory evaluation properties of Garaetteok changed with non-glutinous at different ratios germinated brown rice(GBR). Changes in the moisture content of GBR occurred with increasing non-glutinous levels of(1~3%) increase in the level. The color value decreased by with increasing the GBR, whereas the and b values were both increased. As the result of the measurement using the texture analyzer, hardness, cohesiveness, gumniness, and chewiness of Garaetteok tended to decreased in proportion to the amount of GBR in the formula. In the sensory evaluation, 40% GBR and 60% GBR in color, hardness, springiness, chewiness and overall acceptability than that of add compared to 100% and 80% GBR. And Garaetteok with 40% and 60% GBR showed the highest overall acceptability scores in overall acceptability. Therefore, we concluded that the addition of GBR on to Garaetteok improved the sensory characteristics as well as and delayed the retrogradation.

• Polymer(Korea)
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• v.38 no.6
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• pp.760-766
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• 2014

Bead type super-absorbent resins to be used for release-control were prepared by modification of the inverse suspension polymerization, and their physical properties were characterized. Acrylic acid and acrylamide were used as monomers, and N,N-methylenebisacrylamide was used as crosslinker, controlling the viscosity of monomer solution by adding hydroxyethylcellulose (HEC). SEM studies of the synthesized beads verified that the bead surfaces had many pores with their diameters of several tens nm. The bead sizes were in the range of $500{\sim}3000{\mu}m$, depending on the viscosity of the monomer solution. Both absorbent amount and absorbent rate of the beads were inversely proportional to the bead size, and the maximum water absorbent amount of 1 g beads was determined to be ca. 170~200 g for 5 hrs. The absorbent rate was also dependent on pH change of the aqueous solution, exhibiting the maximum rate in pH ranging from 5 to 11. The absorbent rate decreased as the concentration of salt (NaCl and $MgCl_2$) or ethanol and ethylene glycol increased. Release time of the water absorbed into the bead resins was 700 hrs, confirming the usefulness of the resin for the good release-control materials.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.12
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• pp.1823-1829
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• 2012

Rice noodles are popular worldwide; however, no standard procedure is available for screening the potential for rice flour to make good quality noodles. This study reports two standard laboratory-scale procedures for preparing flat (sheet type) and extruded noodles. Eight rice cultivars were examined and the cooking loss and tensile strength of cooked noodles were determined. It was relatively easy to control the amount of water added to extruded noodles, whereas flat noodles were very sensitive to the amount of water used. Sheet formation was determined based on the amount of moisture content during preparation, and the Chenmaai cultivar was found to be most appropriate for both noodles making procedures and cooking and textural properties. Finally, good noodle making cultivar such as Chenmaai was less likely to be affected by the milling method.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.339-342
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• 2002

This study was comparised physical properties of waxy black rice and waxy rice. In case of physical properties of kernels, weight, length, length/width ratio and volume of waxy black rice were higher than those of waxy rice but width and density were very similar. Moisture gain of kernels of waxy black rices was increased continuously to 40 min. at various soaking temperatures ($20{\sim}50^{\circ}C$) and the water uptake rate constants ($k_0$) of waxy black rices during storage at $20{\sim}50^{\circ}C$ were also increased. The water uptake rate constant ($k_0$) of waxy rice ($0.058\;min^{-1/2}$) was the more fast than that of waxy black rice ($0.033\;min^{-1/2}$) during storage at $4^{\circ}C$. Also hardness reduced rate constant($-k_0$) of waxy rice ($0.048\;min^{-1}$) were the more fast than that of waxy black rice ($0.022\;min^{-1}$) about two times.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.8-15
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• 2011

제습기의 역할은 태양열제습냉방시스템 요소 중에서도 매우 중요하다. 본 논문은 이러한 특성에 맞추어 제작된 장치를 갖고서 제습능력에 영향을 미치는 유량비를 바꾸어 실험한 결과이다. 실험은 크기가 $40m^3$인 항온항습실을 대상으로 이루어졌으며, 향류형 제습기의 수직 높이는 0.4m로 고정되었다. 또한 충진층은 액체흡수제와의 접촉면을 넓게하기 위하여 플라스틱 충진재로 채워져 있으며, 흡수제의 온도는 빠른 변화를 보기 위하여 $15^{\circ}C$로, 농도는 40%로 고정하였다. 액체흡수제의 유량과 습도가 높은 공기의 유량을 각각 3단계로 바꾸어 실험한 결과, 풍량이 높을수록 제습기 효과는 낮아졌으나, 전체적인 제습량에서는 많아졌다. 한편, 제습기에서 액체흡수제 유량이 많을수록 제습되는 수분량이 많아졌으나, 시간의 변화에 따라 제습되는 속도는 현저하게 낮아졌다. 따라서, 향후 실험에서는 유량의 변화 폭을 더욱 확대해서 많은 실험 결과를 확보하고, 이를 모델링화 하여 높은 정확도를 예측할 필요가 있다.

• Food Science and Preservation
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• v.23 no.2
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• pp.194-203
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• 2016

The purpose of this study was to investigate the properties of tteok prepared from white (Samkwang) and brown rice (Heugseol, Heugjinju). The moisture and crude protein contents of rice were 14.89~17.15% and 4.79~6.81%, respectively. The crude lipid and crude ash contents of rice were 0.48~2.66% and 0.39~1.60%, respectively. The water binding capacity of Heugjinju (141.97%) was higher than those of other rice flours. As the soaking time increased, water absorption ability was in the order of Samkwang > Heugseol > Heugjinju. Using a rapid visco analyser (RVA), the initial pasting temperature of Heugseol was the highest, and the peak viscosities of Heugseol were higher than those of other rice flours. The quality characteristics of Tteokbokki tteok were assessed after its preparation by adding different amounts of Heugseol and Heugjinju (0, 5, 10, and 20%, w/w) content. The textural properties (hardness), of Heugseol and Heugseol measured using a texture analyzer, were greater than those of the control. Sensory preference tests revealed that 10% Heugseol and, 10% Heugjinju had the highest scores in appearance, color, and overall acceptability. The sensory test results revealed that Tteokbokki tteok prepared by addition of 10% added brown rice was the best.