• New & Renewable Energy
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• v.1 no.4 s.4
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• pp.19-24
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• 2005

수소 여과용 치밀질 membrane의 제조는 기존의 SC($SrCeO_3$)보다 높은 여과특성을 가지는 BC($BaCeO_3$)구조의 재료를 이용하여 시편을 제조하였고, 시편의 물성은 기공율, 수분에 대한 내구성 그리고 여과 특성을 측정하였다. 우선 열적 안정성 및 수분에 대한 내구성 향상은 $Y_2O_3$를 0.1mol첨가 하였을 때 1% 이내의 기공율을 가지고 있었으며 수분에 대한 안정성을 위해 boiling test에서도 균열이 발생되지 않고 안정적인 것을 확인할 수 있었다. 또한 여과 특성을 향상시키기 위해 Ce과 치환이 가능하고 전도성을 향상시킬 수 있는 $Ga_2O_3$, $La_2O_3$을 치환하여 물성을 측정한 결과 $Ga_2O_3$은 0.05, $La_2O_3$ 0.1mol%가 최적이었으며, 이들 중 $Ga_2O_3$가 0.05mol 첨가 되었을 때 가장 높은 이온 전도도 값을 얻었으며, $La_2O_3$이 첨가된 경우가 다음으로 높게 나타났다. 전자 전도성을 높이기 위하여 Pt를 sol로 만들어 나노 입자로 분산 시키는 방법으로 실험을 실시 $500^{\circ}C$ 이상의 온도에서는 복합전도에 의해 전도도가 향상되어지는 것을 확인할 수 있다. 또한 이들 시편의 여과 특성을 측정한 전도도 측정의 결과와 동일한 결과를 얻을 수 있었다.

• Polymer(Korea)
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• v.36 no.5
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• pp.579-585
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• 2012

Polystyrene/carbon nanotube (CNT) microcellular foams were prepared to have electrically conductive properties via high internal phase emulsion polymerization. In this study, we have investigated the effects of surface modification of CNT, surfactant content and dispersion time to improve the stability of emulsion and the electrical conductivity of foam. Acid treatment and a surfactant were used to effectively disperse CNTs in the aqueous phase. In the organic phase, CNTs were used after a surface modification with organic functional groups. The degree of dispersion of CNTs was estimated by the electrical conductivity of resultant microcellular foams. With raw CNTs dispersed with the surfactant in the aqueous phase, substantial conductivity increase was observed but the foams were slightly shrunk. The foams prepared with organically modified CNTs dispersed in the organic phase showed stable cell morphology without shrinkage, but displayed limitation to improve the conductivity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.506-515
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• 2003

Six barley varieties that showed different degree of drought tolerance were grown with and without drought stress treatment (control), and investigated for the temporal changes in growth and several physiological traits after drought treatment. Soil water potential was -0.05 ㎫ at the initial stage of drought treatment and dropped to -0.29 ㎫ at 19 days after withholding irrigation. Soil water potential (SWP) maintained at -0.05 ㎫ in the control. The dry weight (DW) under the drought treatment were reduced compared to the control as follows: Dicktoo-S (short awn), 69% ; Dicktoo-L (long awn), 70%; Dicktoo-T (tetra), 86%; Dongbori-1, 69%; Suwonssalbori-365, 55% and Tapgolbori, ,37%. Dicktoo lines and Dongbori-1 were more tolerant than Suwonssalbori-365 and Tapgolbori. Leaf relative water contents (RWC) and leaf water potential (LWP) decreased obviously under the drought condition, the decrease being greater especially in the less drought-tolerant barley genotypes. Dongbori-1 and Dicktoo-L in drought treatment showed net photosynthesis of 38% and 17% compared to the control, respectively, and the other four genotypes much lower photosynthesis of 1.1% to 7.0%. Stomatal conductance, mesophyll conductance, and the photochemical efficiency (Fv/Fm) of PS II were reduced by drought treatment, the reduction being greater in drought-sensitive genotypes. The drought-tolerant genotypes had greater osmotic adjustment (OA) capacity under water stress. Thus, the decrease of RWC and LWP was lower and the turgor pressure conservation capacity was higher under water stress in drought-tolerant genotypes. Drought-tolerant genotypes showed less decrease of photosynthesis because stomatal conductance, mesophyll conductance and the ratio (Fv/Fm) of the variable to maximal fluorescence of drought-resistant genotype was decreased less in the drought stress condition. In conclusion, the drought-tolerant genotypes had better water conservation capacity through efficient OA, and this led to the lower decrease of photosynthesis and growth in water stress condition.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.10a
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• pp.188-189
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• 2009

AAO 템플레이트 기공 안에 기상 중합 방식을 이용하여 Poly(3,4-ethylenedioxythiophene) 전도성 나노 튜브를 제조하였다. PEDOT 나노튜브는 나노 단위의 직경과 마이크로 단위의 길이로 조절이 자유로우며 잘 정렬된 구조를 갖는다. PEDOT 나노 튜브의 전도도는 2000 S/cm로써 박막으로 제조된 것에 비해 향상되었으며, XPS, TEM, SEM와 SPM을 통해 형태 및 특성을 확인하였다.

• Journal of agriculture & life science
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• v.46 no.4
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• pp.93-99
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• 2012

This study was conducted to investigate photosynthetic characteristics of two-year-old of Adenophora triphylla var. japonicum grown under control (full sunlight) and three different shading treatment (25, 50, and 75% shading treatment). Total chlorophyll contents like chlorophyll a and b content had not significant difference among treatments. Net photosynthetic rate of control and 25% treatment were higher than 50% and 75% treatment. Seedlings grown under full sunlight showed the highest photosynthetic activity such as photosynthetic rate, stomatal conductance and intercellular $CO_2$ concentration except for water use efficiency which was relative higher under 50% and 75% treatment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.167-174
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• 2000

A glass chamber experiment was conducted to evaluate the impact of ozone (O$_3$) on the physiology of two soybean, Glycine max L. cultivars, 'Hwanggum' and 'Jangyub'. Thirty-day old plants with 1-2 nodes were exposed to $O_3$ of <10 and 150 n1 1$^{-1}$ in the chambers for 8 h d$^{-1}$ for 3 days. Net photosynthesis, stomatal conductance, chlorophyll a, chlorophyll b and total chlorophyll contents, and foliar injury (% injured leaves) were measured. Although foliar damage was more severe on Jangyub than on Hwanggum, net photosynthesis was decreased by 60% on Hwanggum and 13% on Jangyub due to the $O_3$ treatment. Stomatal conductance on Jangyub was twice higher than that on Hwanggum and it was not changed by the $O_3$ treatment. Whereas, stomatal conductance on Hwanggum was 60-80% decreased by $O_3$, Chlorophyll contents did not change due to the $O_3$ treatment or variety. We can conclude that the reduction of net photosynthesis by $O_3$ was mainly due to the decreases of stomatal conductance and Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) activity on dark reaction. And foliar injury and chlorophyll content did not contribute to the net photosynthetic decrease. The gas-exchange variables measured 24 h after the termination of $O_3$ fumigation showed that there was no significant recovery within a day. Since the physiological responses on Jangyub were not much affected by the $O_3$ treatment, this variety could be $O_3$ resistant.

• Journal of Power System Engineering
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• v.12 no.5
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• pp.54-58
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• 2008

최근 열교환기의 향상을 위해 발포다공성매체의 적용이 증가하고 있다. 열교환기의 적용에 있어서 발포다공성매체의 이점을 살펴보기 위해 본 연구에서는 2가지 실험을 수행하였다. 첫 번째는 수력의 관점에서 투과계수 및 내부계수를 결정하는 것이고, 두 번째는 열교환의 관점에서 다공성매체의 유효전도율을 측정하는 것이다. 본 실험에서는 기공도는 거의 같으나 기공의 크기가 각각 20 ppi와 40 ppi인 구리 다공성매체를 사용하였다. 실험의 결과는 40 ppi 크기의 다공성매체가 수력과 열교환, 두가지 관점 모두에서 보다 높은 저항 효율을 나타낸다는 것을 보여준다.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.251-259
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• 2005

In order to characterize the influence of the reaction-site density on the cathodic polarization property of LSCF, we chose the porosity of LSCF as a main controlling variable, which is supposed to be closely related with active sites for the cathode reaction. To control the porosity of cathodes, we changed the mixing ratio of fine and coarse LSCF powders. The porosity and pore perimeter of cathodes were quantitatively analyzed by image analysis. The electrochemical half cell test for the cathodic polarization was performed via 3-probe AC-impedance spectroscopy. According to the investigation, the reduction of oxygen at LSCF cathode was mainly controlled by following two rate determining steps; i) surface diffusion and/or ionic conduction of ionized oxygen through bulk LSCF phase, ii) charge transfer of oxygen ion at cathode/electrolyte interface. Moreover, the overall cathode polarization was diminished as the cathode porosity increased due to the increase of the active reaction sites in cathode layer.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2005.11a
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• pp.141-143
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• 2005

죽절초는 높은 광도 보다는 낮은 광도에서 생육이 건전하게 유지되고 광합성률이 높은 것으로 나타났다. 그러므로 죽절초가 최적으로 생육할 수 있는 조건은 전광의 약 70%정도로 낮은 광도인 실내환경에서 잘 적응할 것으로 추정되어 실내 조경 식물소재로 도입한다면 좋은 관상수가 될 수 있음을 알 수 있었다. 식물 생장의 중요 조건 중 하나인 기공전도도 또한 70% 비음처리구에서 가장 높게 나타나 실내 조경식물로 죽절초가 생육하는 경우에 실내의 낮은 광도에서도 원활한 기공개폐가 이루어져서 실내공기 오염도를 낮추는데 중요한 역할을 할 수 있음을 보여주었다.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.133-138
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• 2002

This study was conducted to investigate the effece of NaCl concentrations on the growth, photosynthetic rate and mineral uptake of tomato, red pepper, and egg Plant in Pot culture. The growth such as plant height, plant fresh and dry weight, root fresh and dry weight and dried matter rate was decreased as NaCl concentrations were increased. Specially, the growth inhibition of tomato and egg plant was shown at over 40 mM NaCl, and that of red pepper at 20 mM NaCl. Yield of tomato and egg Plant was reduced at over 20 U NaCl, that of red pepper at over 10 mM NaCl. Yield reduction was affected by the number of fruit at low concentration and by mean weight and number of fruit at high concentration. Photosynthetic rate, water potential and stomatal conductance were decreased as NaCl concentrations were increased. The higher the concentration of NaCl, the lower the mineral uptake such as T-N, P, K, Ca and Mg, however, the higher the content of Na and Cl.