• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.174-179
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• 2007

Although the relationship between fermentation and factors such as soil water, redox potential, rootstocks and climatic conditions has been reported, its mechanism of fermentation is still not clear. Transpirations of leaf and fruit at different climatic conditions, influence of soil water potential and atmospheric vapor pressure deficit (VPD) on fermentation were evaluated. Transpiration rate decreased with decreasing soil temperature and soil water potential. Low VPD conditions which occurred during low air temperature and high humidity also decreased transipration rate. These data exhibit that fruit water balance affected by various factors relate to transpiration. Our results also indicate that high hydraulic conductance of root, high soil water potential and low VPD condition exert a significant effect on fermention of oriental melon and so called "water filled fruit".

• Korean Journal of Environmental Agriculture
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• v.23 no.3
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• pp.128-132
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• 2004

Ozone effects were studied by plant growth chamber to evaluate the impact of ozone ($O_3$) on the physiology of two hot pepper, Capsicum annuum L., cultivars, 'Dabotab' and 'Buchon'. Forty-day old plants with $5{\sim}7$ leaves were exposed to $O_3$ of <20 and 150 nL/L for 8h/d for 3 days. Net photosynthesis and stomatal conductance were measured and foliar injury was described. Foliar damage due to the treated $O_3$ was different from the varieties. 'Dabotab' was most sensitive to $O_3$ and 'Buchon' was resistant. Symptom of ozone damage on the leaves was bifacial necrosis. Decreases of net photosynthesis by $O_3$ were 56% and 40% on 'Dabotab' and 'Buchon', respectively. Decreases of stomatal conductance by $O_3$ were 66% and 63% on each variety. $O_3$ damage on net photosynthesis was started at the low levels of light on the two hot peppers. In addition, assimilation-internal $CO_2$ concentration curves were not different from the two varieties. In conclusion, $O_3$ closed the stomata and decrease net photosynthesis on hot peppers regardless of the ozone sensitivity on leaf injury, but the difference of ecophysiological responses between the two varieties was not found clearly.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.369-375
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• 2007

We examined two Populus species (Populus euramericana and Populus alba ${\times}$ Populus glandulosa) trees grown under livestock waste leachate treatment in the field. We investigated their physiological properties (photosynthetic rate, chlorophyll contents, transpiration rate and intercellular $CO_2$ concentration) and antioxidant enzyme activities. Ascorbate peroxidase and glutathione reductase were analyzed. According to our measurements, P. euramericana at control site showed a lower total chlorophyll contents, photosynthetic rate, intercellular $CO_2$ concentration, transpiration and stomatal conductance than those of trees at treatment site. P. alba ${\times}$ P. glandulosa showed low stomatal conductance and low photosynthetic rate.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.269-275
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• 2005

We analyzed the unit cell performance against the cathode porosity, which is supposed to be closely related with active sites for the cathode reaction. In order to fabricate the unit cells with different porosity in the cathode layer we changed the mixing ratio of fine and coarse LSCF cathode powders. The final porosity of each cathode layer was 14, 23, 27, $39\%$ respectively. According to the electrochemical analysis of unit cell performance via DC current interruption and AC impedance method, the electrodic polarization resistance was diminished as the cathode porosity increased. The decrease of polarization resistance was attributed due to the increase of active reaction sites and the enhancement of overall unit cell performance could be explained in the same line.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.2
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• pp.111-118
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• 2010

Stress due to excess water is one of the most limiting factor for soybeans to high yield under wet climates. This study aimed to identify the photosynthetic responses of soybeans to waterlogged growing condition with 5 soybean varieties by waterlogging for 10 days at V5 and R2 stage, respectively. Chlorophyll fluorescence decreased more rapidly at R2 stage waterlogging than at V5 stage waterlogging in all soybean tested varieties. The degree of recovery was much more in Pungsannamulkong and Muhankong( 95～97% of control) than in Jangyeobkong and Myungjunamulkong at 5 days after waterlogging. Photosynthetic rate, transpiration and stomatal conductance were also increased more rapidly in Pungsannamulkong and Muhankong than in Jangyeobkong and Myungjunamulkong after waterlogging irrespective of waterlogging stages. As the result of multiple regression analysis in order to identify the effects of stomatal conductance and transpiration to the photosynthetic rate, the R2 value of stomatal conductance in control and waterlogging treatment was 0.7293 and 0.7582, respectively. If the transpiration, another dependent variable, was added to the regression formula, there was not so big difference in the variation of photosynthetic rate. This result means that if just one factor of them(the stomatal conductance and transpiration) be measured in the case of waterlogged condition, the changes of photosynthetic rate can be estimated.

• Korean Journal of Agricultural and Forest Meteorology
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• v.11 no.4
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• pp.143-150
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• 2009

Deicing salt is used to melt snow and ice on the road for traffic safety during the winter season, which accumulates in the roadside vegetation and induces visible injuries. The damage may accelerate particularly when it coincides with early spring leaf out. In order to better understand the response mechanisms, C. kousa (3-year-old) was irrigated twice prior to leaf bud in a rhizosphere with solutions of 0.5, 1.0, and 3.0% calcium chloride ($CaCl_2$) concentration, that were made by using an industrial $CaCl_2$ reagent practical deicing material in Seoul. Physiological traits of the mature leaves were progressively reduced by $CaCl_2$ treatment, resulting in reductions of total chlorophyll contents, chlorophyll a:b, photosynthetic rate, quantum yield, stomatal conductance, $F_V/F_M$, and NPQ. On the contrary, light compensation point and dark respiration were increased at high $CaCl_2$ concentration. A decrease in intercellular $CO_2$ concentration by stomatal closure first resulted in a reduced photosynthetic rate and then was accompanied by low substance metabolic rates and photochemical damage. Based on the reduction of physiological activities at all treatments ($CaCl_2$ 0.5%, 1.0%, and 3.0%), C. kousa was determined as one of the sensitive species to $CaCl_2$.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.93.1-93.1
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• 2018

그래핀 에어로겔은 우수한 전기 열 전도도, 기계적 특성, 넓은 표면적으로 베터리, 약물방출 등 다양한 분야에서 많은 연구가 진행되고 있다. 특히, 그래핀 에어로겔은 친수성, 생체안전성, 삼차원구조의 특성으로 우수한 약물방출형 임플란트 소재로의 활용이 기대된다. 본 연구에서는 그래핀 산화물의 수열처리를 통해 그래핀 하이드로겔 형성 후, 저온건조와 동결건조를 이용하여 그래핀 에어로겔을 제조하였다. 그래핀 산화물과 그래핀 에어로겔의 특징들을 XRD, SEM, XPS, Raman등을 통해 확인하였으며, 그래핀 에어로겔에서 건조방법과 건조시간에 따른 기계적 강도, 기공구조의 제어가능성을 BET, SEM등의 분석을 통해 확인하였다. 이러한 기공구조 제어를 통해 약물방출 특성을 측정하였으며, 인체 삽입형 임플란트로서의 활용 가능성을 확인할 수 있었다.

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.117-117
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• 2019

• Membrane Journal
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• v.25 no.2
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• pp.171-179
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• 2015

Perfluorinated sulfonic acid ionomers (PFSAs) have been widely as solid electrolyte materials for polymer electrolyte membrane fuel cells, since they exhibit excellent chemical durability under their harsh application conditions as well as good proton conductivity. Even PFSA materials, however, suffer from physical failures associated with repeated membrane swelling and deswelling, resulting in fairly reduced electrochemical lifetime. In this study, pore-filling membranes are prepared by impregnating a Nafion ionomer into the pore of a porous PTFE support film and their fundamental characteristics are evaluated. The developed pore-filling membranes exhibit extremely high proton conductivity of about $0.5S\;cm^{-1}@90^{\circ}C$ in liquid water.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.68-71
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• 2003

Experiments were conducted to investigate optimal ionic salt strength in nutrient solution for small plug seedlings of ‘Nokgwang’ and ‘Kwari’ green pepper. Plant height increased with increasing ionic salt strength. total leaf area was 72％ greater in ‘Nokgwang’ and 18% greater in ‘Kwari’with 2.0 ionic salt strength than that with 1.0 strength. Dry weight per plant tended to increase at higher ionic salt strengths in ‘Kwari’, but to decrease in ‘Nokgwang’ Chlorophyll content increased with increasing ionic salt strength in both cultivars. Photosynthetic rate, stomatal conductance, and transpiration rate were higher for plants fertilized with 1.5 strength than other strengths in both cultivars. Photosynthetic rate peaked at 8.74 $\mu$mol$.$m$^{-2}$ s$^{-1}$ in ‘Nokgwang’ and 5.70 $\mu$mol$.$m$^{-2}$ s$^{-1}$ in‘Kwari’with 1.5 ionic salt strength.