• 생물환경조절학회지
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• 제22권2호
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• pp.182-187
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• 2013

밀폐된 식물공장 환경에서 환경 조절 및 에너지 소비예측을 위해서는 환경요소들의 변화 요인을 파악해야 한다. 식물체는 광합성 과정에서 많은 양의 물을 증산을 통해 대기 중으로 방출하게 되는데, 일반적으로 식물공장의 특성상 비교적 높은 습도 유지가 필요하며, 증산은 실내 습도에 직접적인 영향을 주기 때문에 식물의 증산량에 대한 정량화가 필요하다. 본 연구에서는 식물공장 생육조건에서 4가지 품종의 상추를 재배하면서 생육기간에 따른 엽면적 변화와 증산속도를 측정하고 이를 바탕으로 Penman-Monteith 방정식을 식물공장 조건에 맞게 변형시켰다. 그리고 이러한 결과들을 토대로 식물공장에서 재배 기간 중 증산으로 인해 발생하는 수분의 양을 시뮬레이션을 통해 예측하였다. 그 결과 작물의 엽면적과 증산속도는 생육기간이 진전됨에 따라 점차 증가하는 것으로 나타났으며 엽면적과 증산량 사이는 비례관계를 나타냈다. 증산량 추정 모델식 변형은 일반적으로 다양한 환경 요인들에 의해 증산량이 결정되던 기존의 모델식들에 비해 엄밀한 환경 요소들에 대한 제어가 가능한 식물공장에서 증산량은 환경 요소들은 상수로 취급 가능하며, 작물의 엽면적지수의 변화에 대해서만 주로 결정되었다. 또한 설정된 환경 조건에서 생육기간에 따른 증산량 추정모델을 이용하여 전체 생육기간 중 작물 개체당 누적 증산량을 높은 결정계수($r^2$)로 예측할 수 있었다. 이렇게 예측된 증산량은 식물공장 환경 제어 기술 중 냉난방 부하 계산 및 관수 계획을 세우는데 활용 가능할 것이다.

• 한국산림과학회지
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• 제96권3호
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• pp.369-375
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• 2007

이태리 포플러와 현사시를 대상으로 야외에서 돈분침출수를 관수하고 광합성특성, 엽록소함량, 증산량, 세포내 이산화탄소농도, ascorbate peroxidase, glutathione reductase 효소의 활성을 조사, 분석하였다. 이태리 포플러의 경우 엽록소 함량, 광합성률, 증산률, 기공전도도, 엽육세포내 $CO_2$ 농도가 돈분침출수 처리구가 대조구에 비해 높은 경향을 보였다. 또한 현사시의 엽록소 함량은 돈분처리구에서 대조구와 비슷하였지만 광합성률과 증산률, 기공전도도가 돈분침출수 처리구에서 대조구에 비해 약간 감소하는 경향을 보였다. 이로 미루어 이태리포플러를 돈분침출수가 유출되는 지역의 phytoremediation으로 활용하면 좋을 것으로 판단된다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제3권2호
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• pp.121-129
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• 1999

Photosynthesis and transpiration rates were simultaneously measured in attached sunflower leaves(Helianthus annuusL. cv. Russian Mammoth) during exposure to $NO_2$ and $O_3$ to determine the effect of mixed gan on photosynthesis and the stomatal aperture. The application of $O_3$ alone reduced both the net photosynthetic and transpiration rates. An analysis of the $CO_2$ diffusive resistances indicated that the main cause affecting photosynthesis reduction during $O_3$ exposure was not the internal gas phase of the leaf $(rCO_2^{liq})$ but rather the liquid phase or mesophyll diffusive resistance $(rCO_2^{liq})$, suggesting that there is a very concomitant relation between photosynthetic reduction and $rCO_2^{liq}$. The application of NO2 alone caused a marked reduction of the net photosynthesis yet no significant reduction of transpiration, indicating that NO2 affects the $CO_2$ fixation processes with no inluence on the stomatal aperture. A greter reduction in the photosynthesis of sunflower plants was caused by the application of $NO_2$ alone as compared to a combination of $NO_2$ and $O_3$. $NO_2$ alone reduced the photosynthetic rate by 90%, whereas a mixture of NO2 and O3 reduced it by 50%.

• 한국조경학회지
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• 제27권4호
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• pp.23-28
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• 1999

This study measured transpiration rate of urban trees and albedos of urban surfaces, and examined the function of microclimate amelioration by urban greenspace. Transpiration rates of trees were highest in July and August of growing months. Transpiration per unit leaf area for the two months was 300-350 g/$m^2$/h for Platanus occidentalis, 210-270 g/$m^2$/h for Ginkgo biloba and Zelkova serrata, and 130-140 g/$m^2$/h for Acer palmatum. Surface albedos were 0.09 for asphalt paving and 0.68 for white wall, which reveals that light-colored surfaces are better than dark-colored ones to lower the heat build-up. Due to lack of evapotranspiration, concrete surfaces were, at t midafternoon maximum, 8$^{\circ}C$ hotter than grass ones, though the albedo of concrete paving was higher thant that of grass and trees. Summer air temperatures at places with 12% and 22% cover of woody plants were, respectively, 0.6$^{\circ}C$ and 1.4$^{\circ}C$ cooler than a place with no vegetation. To mitigate the impacts of urban heat islands, required are minimization of hard surfaces, light-coloring for building surfaces, and greenspace enlargement including more plantings.

• The Korean Journal of Ecology
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• 제21권1호
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• pp.89-96
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• 1998

The diurnal changes of the stomatal conductance, transpiration and leaf water potential were measured in order to assess the water relations characteristics of Pueraria thunbergiana in August of 1995 and 1996. The results showed two different responses depending on the duration of rainless days. The microclimatic conditions were highly stressful on 2 August. Daily maximum temperature reached to $39.0{\circ}C$ and vapor pressure deficit was 3.55 KPa. During this time the leaf water potential decreased to -1.02 MPa and a marked reduction of stomatal conductance was shown. However, on 15 August the stomatal conductance increased with increment of photon flux density, and transpiration was highly maintained during the day time. Minimum leaf water potential was only -0.47 MPa in spite of high transpiration rate. Furthermore, on 15 August reduced leaf water potential during the day time was recovered rapidly with decrease of photon flux density, whereas recovery of leaf water potential on 2 August was delayed. However, reduced leaf water potential on 2 August was recovered untile the next dawn. Osmotic potential at turgor loss point of Pueraria thunbergiana on 2, 3 and 15 August was -1.79, -1.70 and -1.60 MPa, respectively. The vapor pressure deficit is more contributive to the regulation of stomatal conductance than leaf water potential.

• 한국약용작물학회지
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• 제26권2호
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• pp.181-187
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• 2018

Background: This study aimed to investigate out the influence of drought stress on the physiological responses of Dendropanax morbifera seedlings. Methods and Results: Drought stress was induced by discontinuing water supply for 30 days. Under drought stress, photosynthetic activity was significantly reduced with decreasing soil water content (SWC), as revealed by the parameters such as Fv/Fm, maximum photosynthetic rate ($P_{N\;max}$), stomatal conductance ($g_s$), stomatal transpiration rate (E), and intercellular $CO_2$ concentration (Ci). However, water use efficiency (WUE) was increased by 2.5 times because of the decrease in $g_s$ to reduce transpiration. Particularly, E and $g_s$ were remarkably decreased when water was withheld for 21 days at 6.2% of SWC. Dendropanax morbifera leaves showed osmotic adjustment of -0.30 MPa at full turgor and -0.13 MPa at zero turgor. In contrast, the maximum bulk modulus of elasticity ($E_{max}$) did not change significantly. Thus, Dendropanax morbifera seedlings could tolerate drought stress via osmotic adjustment. Conclusions: Drought avoidance mechanisms of D. morbifera involve reduction in water loss from plants, through the control of stomatal transpiration, and reduction in cellular osmotic potential. Notably photosynthetic activity was remarkably reduced, to approximately 6% of the SWC.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제31회 추계학술대회논문집
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• pp.36-40
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• 2008

마이크로 추진장치에서 노즐의 소형화는 많은 유동손실을 유발한다. 이러한 유동손실을 극복하기 위해 본 연구에서는 열적발산원리를 이용한 새로운 개념의 마이크로 추진장치에 대한 기초연구를 진행하였다. 움직이는 부품 없이 오직 온도구배만으로 추진제를 낮은 온도에서 높은 온도로 자체 펌핑이 가능한 열적발산장치를 설계, 제작 하였으며, 진공환경에서 누센수에 따른 멤브레인 압력구배효율을 분석하였다. 또한 기존 누센펌프의 멤브레인인 폴리이미드와 종이재질의 전통 한지를 사용하여 질유량 특성을 비교하였다.

• Journal of Plant Biotechnology
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• 제33권2호
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• pp.133-137
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• 2006

Evaluation of physiological performance of trehalose-producing transgenic rice line was conducted to investigate drought tolerance at early growth stage. Under artificially induced drought condition of 8% polyethylene glycol 6000, this transgenic rice line had leaf photosynthetic rate of 11.08 uml CO$_2$ $m^{-2}s^{-1}$, leaf transpiration rate of 8.38 mmol $H_2O$ $m^{-2}s^{-1}$ and leaf water potential of -1.12 MPa after 96 hours of treatment. Nakdongbyeo, the parent of this tyansgenic rice line, had photosynthetic rate of 15.42 $\mu$mol CO$_2$ $m^{-2}s^{-1}$, leaf transpiration rate of 8,04 mmol $H_2O$ $m^{-2}s^{-1}$ and leaf water potential of -0.88 MPa. The other variety used in this experiment for comparison, IR 72, showed higher values than both tyansgenic rice line and variety Nakdonbyeo on all three parameters; leaf photosynthetic rate of 20.61 $\mu$mol CO$_2$ $m^{-2}s^{-1}$, leaf transpiration rate of 12.88 mmol $H_2O$ $m^{-2}s^{-1}$, and leaf water potential of -0.82 MPa. So this transgenic rice line did not show superior performance in leaf transpiration rate, leaf photosynthetic rate and leaf water potential compared to variety Nakdongbyeo. This result along with visual observation on leaf rolling and drying during the experimental period indicated poor physiological performance of this transgenic rice line. Further studies on metabolic status of stress-induced trehalose, along with study on physiological response of this transgenic rice line during drought stress would shed more light on overall physiological performance of this transgenic rice line.

• 생물환경조절학회지
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• 제13권4호
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• pp.240-244
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• 2004

순환식 양액재배시 계면활성제가 무기이온 흡수 증진에 미치는 영향을 알아보고자 상추의 생육, 광합성율, 증산율 및 무기이온 함량을 분석하였다. 상추 생육은 $0.3mg{\cdot}L^{-1}$ PVA-95처리에서 가장 높았으며, l/2배액에서 재배된 상추의 생육도 양호하였다. 칼슘 함량이 증가된 $0.3mg{\cdot}L^{-1}$ CLS 처리의 상추는 생육이 낮음에도 불구하고 높은 증산율과 광합성율 및 엽내 카리, 칼슘 및 마그네슘 함량이 높았다. 따라서 높은 생육량과 비료 절감 효과가 인정된 PVA-95 처리와 CLS 처리에 의한 엽내 무기 성분 함량 증가가 인정됨에 따라 수경재배 상추의 고품질 생산에 유용하게 사용 가능하리라고 판단된다.

• 한국재료학회지
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• 제20권3호
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• pp.111-116
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• 2010

Chloride-based fluxes such as NaCl-KCl are used in the refining of Al melt. The vapor pressure of the chloride is one of the fundamental pieces of information required for such processes, and is generally high at elevated temperatures. In order to measure the vapor pressure for chlorides, the apparatus for the transpiration method was assembled in the present study. The vapor pressure of $ZnCl_2$ and $FeCl_2$, which is related with the process of aluminum refining and the recovery of useful elements from iron and steel industry by-products, was also measured. In the measurement of vapor pressure by the transpiration method, the powder of $ZnCl_2$ or $FeCl_2$ in a alumina boat was loaded in the uniform zone of the furnace with a stream of Ar. The weight loss of $ZnCl_2$ and $FeCl_2$ after holding was measured by changing the flow rate of Ar gas (10 sccm -230 sccm), and the partial pressures of $ZnCl_2$ and $FeCl_2$ were calculated. The partial pressures within a certain range were found to be independent of the flow rate of Ar at different temperatures. The vapor pressures were measured in the temperature range of 758-901K for $ZnCl_2$ and 963-983K for $FeCl_2$. The measured results agreed well with those in the literature.