• Journal of Bio-Environment Control
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• v.27 no.3
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• pp.231-238
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• 2018

Chlorophyll fluorescence, chlorophyll content, graft-taking and growth of grafted cucumber seedlings as affected by photosynthetic photon flux (PPF) of LED lamps were analyzed in this study. Four PPF levels, namely 25, 50, 100, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ were provided to investigate the effect of light intensity on the chlorophyll fluorescence, chlorophyll content, graft-taking and growth of grafted cucumber seedlings. Air temperature, relative humidity, and photoperiod for graft-taking were maintained at $25^{\circ}C$, 90%, $16h{\cdot}d^{-1}$, respectively. Maximum quantum yield (Fv/Fm) of rootstock as affected by PPF was found to be 0.84-0.85 and there was no significant change in Fv/Fm. Even though Fv/Fm of scion measured at 2 days after grafting was lowered to 0.81-0.82, after then it gradually increased with increasing PPF. At 4 days after grafting, the chlorophyll content extracted from scion increased with increasing PPF. Graft-taking ratio of grafted cucumber seedlings was 90-95% as PPF was ranged from $25{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ to $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. However, the graft-taking ratio of grafted seedlings healed under PPF of $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ was decreased to 80%. Maximum PPF measured required for smooth joining of rootstock and scion was assumed to be $100{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. At healing stage of grafted cucumber seedlings, Fv/Fm of scion decreased and at least two days after grafting were required for rooting of grafted seedlings. Chlorophyll fluorescence response of rootstock and scion was linked to light irradiation. Therefore, it was concluded that physical environment including light and humidity during healing process of grafted seedlings should be controlled more precisely to facilitate root formation and to prevent scion from lowering Fv/Fm. Further studies are required to investigate the effects of root development and joining of vascular bundles of grafted seedlings on the chlorophyll content of scion.

• Journal of the Korean Chemical Society
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• v.38 no.8
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• pp.598-602
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• 1994

Light-induced electron transfer reaction within binuclear complex $(NC)_5FeII-L-CoIII(NH_3)_5$ was studied with steady-state photolysis and the rate constants were measured for various bridging lignands. klight and quantum yields for BP, PHEN, DAP having conjugation between metal binding sites were about $3{\times}10^{-2} sec^{-1}$ and 1, and for BPEA having no conjugation were about $2{\times}10^{-4} sec^{-1}$ and 0.03. Light-induced electron transfer reaction within binuclear complex was proved to be the chemical mechanism which had charge transfer excited state MLCT*.

• Journal of the Korean Chemical Society
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• v.26 no.3
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• pp.172-178
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• 1982

A psoralen-DNA monoadduct analogue, 4',5'-dihydropsoralen (DHP) is synthesized and its photophysical properties such as fluorescence quantum yield (0.08), phosphorescence quantum yield (0.013), fluorescence lifetime (0.95ns), and phosphorescence lifetime(0.039s) were measured in ether solution and in frozen matrix state at 77K. The photocycloaddition reaction of DHP with tetramethylethylene(TME) was carried out in solution and in the frozen state. The major photoadduct was isolated and characterized by elemental analysis and physical methods such as UV, IR, NMR, and mass spectrometry. The major DHP-TME photoadduct was proved to be an 1 : 1 $C_4$-cycloadduct formed through 2 + 2 cycloaddition of the pyrone double bond of DHP to TME.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.57-57
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• 2019

실내 수준에서 조사되는 광량조건에 따른 자생 상록활엽 2종의 생육과 광화학반응을 조사하였다. 식물재료는 3년생 사철나무(Euonymus japonicus Thunb.) 및 2년생 돈나무[Pittosporum tobira (Thunb.) W. T. Aiton] 실생묘로 유리온실에서 재배하면서 실험에 사용하였다. 실내 광량은 10, 50, 100 및 200 PPFD(${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 달리하여 8주간 재배하였으며, 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$), 습도($55{\pm}3%$) 및 관수(1회/3일)조건은 고정되었다. 생육특성 및 광화학반응의 요인들이 측정되었으며, 동일기간 동안 유리온실에서 재배된 식물을 대조구로 사용하였다. 실험의 결과, 사철나무는 100, 200 PPFD의 광량에서 대조구에 비해 초장, 줄기직경, 엽수 및 엽장의 생육반응이 우수하였으며, 엽록소함량은 100 PPFD 이상의 광량에서 감소하였다. 또한 100 PPFD 이상의 광량에서 스트레스지수(Fm/Fo), 최대양자수율(Fv/Fm) 및 전자전달효율(ETo/RC)이 감소하였으며, 이는 대조구와도 유사한 경향이었다. 돈나무는 모든 광량조건에서 줄기직경과 엽폭을 제외하고 대조구와 관계없이 생육반응이 일정하였다. 그러나 스트레스지수와 최대양자수율은 10 PPFD 처리구에서 가장 낮게 조사되었고, 비광학적 에너지의 손실(DIo/RC)은 2.53으로 가장 높았다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.55-55
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• 2019

본 연구에서는 실내에 조사되는 다양한 광량하에서 녹나무과 목본 2종을 재배하면서 생육반응을 조사하였다. 식물재료는 참식나무[Neolitsea sericea (Blume) Koidz.]와 후박나무(Machilus thunbergii Siebold & Zucc.)의 3년생 실생묘를 사용하였다. 실험공간은 광량을 10, 50, 100 및 200 PPFD (${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 달리하였으며, 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$), 습도($55{\pm}3%$) 및 관수(1회/3일) 조건이 동일하게 유지되는 밀실로 조성되었다. 각 광량조건 하에서 8주간 재배된 식물의 생육특성 및 광화학반응이 조사되었으며, 유리온실에 동일 기간동안 재배한 식물과 비교하였다. 연구 결과, 참식나무는 광량에 관계없이 초장을 제외한 전반적인 생육반응이 유사하였으며, 엽록소함량(SPAD)은 광량이 증가함에 따라 감소하는 경향이었다. 최대양자수율(Fv/Fm) 및 스트레스지수(Fm/Fo)는 200 PPFD에서 유의한 차이를 나타냈으며, 이는 대조구와 유사한 경향이었다. 후박나무는 대조구와 비교하여 모든 광량조건에서 초장이 감소하였으며, 특히 10 PPFD에서는 잎의 탈락에 따른 관상가치가 저하되었다. 엽록소함량은 100, 200 PPFD 광량에서 감소하였으며, 대조구도 유사한 경향을 나타냈다. 또한 유리온실의 대조구와 100, 200 PPFD 광량에서 최대양자수율, 스트레스지수 및 PSII 성능지수(Pi_Abs)의 유의한 차이가 확인되었다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.61-61
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• 2019

본 연구에서는 실내 광조건에서 자생 장미과 상록 활엽 목본 2종의 생육반응을 조사하였다. 식물재료는 다정큼나무[Rhaphiolepis indica var. umbellata (Thunb.) Ohashi]와 비파나무[Eriobotrya japonica (Thunb.) Lindl.]의 3년생 실생묘를 사용하였다. 실내 광량은 10, 50, 100 및 200 PPFD (${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 설정되었으며, 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$), 습도($55{\pm}3%$) 및 관수(1회/3일) 주기는 일정하게 유지하였다. 실내에서 8주간 재배한 다음 유리온실에서 동일 기간동안 재배된 대조구와 생육 및 광합성 능력 등을 비교하였다. 연구 결과, 다정큼나무의 생육은 200 PPFD에서 대조구와 유사한 수준이었으며, 줄기직경은 광량과 정비례하는 경향이었다. 엽수는 대조구에 비해 고 광량(100, 200 PPFD) 조건에서 유의적으로 높은 결과를 보였다. 처리 별 최대 양자수율(Fv/Fm) 및 광계II 성능지수(Pi_Abs)는 대조구와 유사한 수준이었으며, 광량에 따른 유의적인 차이가 없었다. 비파나무는 재배기간 동안 광량에 관계없이 생육변화가 크지 않았으나, 엽록소함량은 200 PPFD에서 가장 많았다. 한편 10 PPFD에서는 모든 개체의 잎 고사에 따른 관상가치가 하락하였다. Fv/Fm은 200 PPFD에서 대조구와 유사한 수준이었으며, Pi_Abs는 저광량(10, 50 PPFD) 조건에서 유의적으로 높은 수치였다.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.60-60
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• 2019

개비자나무[Cephalotaxus harringtonia (Knight ex Forbes) K. Koch]와 비자나무[Torreya nucifera (L.) Siebold & Zucc.]의 3년생 실생묘를 유리온실에 재배하면서 실험재료로 사용하였다. 실내의 광량을 측정하여 10, 50, 100 및 200 PPFD (${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$)로 설정하였다. 광량을 제외한 광주기(12/12 h), 온도($25{\pm}1^{\circ}C$), 습도($55{\pm}3%$) 및 관수(1회/3일)주기를 일정하게 유지시킨 밀실에서 8주간 재배하였다. 유리온실에서 재배중인 식물과 광량별 처리구의 초장, 줄기직경, 엽수, 엽장, 엽폭, 엽록소함량(SPAD) 및 광화학반응을 평가하였다. 개비자나무의 생육결과, 모든 광량조건에서 줄기직경과 엽록소함량이 증가하는 경향을 보였으며, 초장, 엽폭의 경우 대조구와 유의한 차이가 없었다. 스트레스지수(Fm/Fo), 최대양자수율(Fv/Fm) 및 광계II 성능지수(Pi_Abs)는 대조구에 비해 모든 광량에서 증가하는 경향을 나타냈다. 10 PPFD의 광량을 제외한 처리구에서 재배된 비자나무의 초장, 줄기직경, 엽장, 엽폭은 대조구와 유사한 경향을 나타냈다. 한편, 엽수와 엽록소함량은 대조구에 비해 우수하였다. Fm/Fo, Fv/Fm, Pi_Abs 및 비광학적 에너지의 손실(DIo/RC)은 모든 광량처리구에서 대조구에 비해 유의적으로 높은 측정값을 나타냈다.

• Journal of Powder Materials
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• v.31 no.2
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• pp.169-179
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• 2024

Colloidal quantum dot (QDs) have emerged as a crucial building block for LEDs due to their size-tunable emission wavelength, narrow spectral line width, and high quantum efficiency. Tremendous efforts have been dedicated to improving the performance of quantum dot light-emitting diodes (QLEDs) in the past decade, primarily focusing on optimization of device architectures and synthetic procedures for high quality QDs. However, despite these efforts, the commercialization of QLEDs has yet to be realized due to the absence of suitable large-scale patterning technologies for high-resolution devices., This review will focus on the development trends associated with transfer printing, photolithography, and inkjet printing, and aims to provide a brief overview of the fabricated QLED devices. The advancement of various quantum dot patterning methods will lead to the development of not only QLED devices but also solar cells, quantum communication, and quantum computers.

• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.532-540
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• 2021

Sodium dodecanoyl-4-oxybenzenesulfonate (DOBS) salt is a substance that exhibits effective bleaching and antimicrobial abilities at low temperatures. A mild and efficient synthesis method of DOBS starting from dodecanoyl chloride and sodium 4-hydroxybenzene sulfonate was investigated under alkaline conditions using a water (W)-polar aprotic solvent system. First, the reaction was carried out using only water as a solvent system with the variables of temperature and time. The yield was found to be as low as about 5% in most cases under the reaction conditions of more than 30 ℃ and 1 h. In order to develop an efficient solvent system, the effect on the yield of DOBS was evaluated in various solvent systems which were prepared by changing the type of polar aprotic solvents while mixing them with the water. A solvent system in which acetone (AC) and water were mixed showed the best yield and about 82 % under mild reaction conditions (30 ℃, 1 h and atmospheric pressure) was obtained. The prepared DOBS showed good bleaching and antimicrobial activities indicating that it could be used an excellent bleach activator.

• Korean Journal of Environmental Biology
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• v.30 no.3
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• pp.210-218
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• 2012

The morphological characteristics, carbon and nitrogen concentrations, stable isotope values and photosynthetic rates of Porphyra yezoensis were studied at the main purple lavers production areas on southwestern coast of Korea. The morphological characteristics of leaf length, leaf width and weight of Porphyra blades were between 11.6~16.3 (average 13.8) cm, 4.6~6.3 (average 5.4) cm, $1.1{\sim}2.6(average\;1.86)g\;DW\;m^{-2}$, respectively. Photosynthetic pigment of Chl a concentration of Porphyra blades was between $2.18{\sim}17.77(average\;9.65)mg\;DW\;Chl\;a\;m^{-2}$. Carbon and nitrogen concentrations of Porphyra blades was between $201{\sim}317(average\;240)mg\;DW\;g^{-1}$, $39.8{\sim}50.0(average\;43.5)mg\;DW\;g^{-1}$ and C/N ratio 5.0~6.7 (average 5.5). The range of average ${\delta}^{13}C$ and ${\delta}^{15}N$ values of Porphyra blades was between - 25.6 to - 24.0 (average - 24.7)‰ for ${\delta}^{13}C$, and 1.3 to 4.1 (average 2.1)‰ for ${\delta}^{15}N$. Photosynthetic characteristics of seaweeds measured by pulse amplitude modulation (PAM) fluorometry was used as an indicator of photosynthetic activity. We use Diving-PAM fluorometry to examine photosynthetic rates of the seaweeds Porphyra yezoensis at each station. Maximum quantum yield of Porphyra blades was between 0.46~0.55 (average 0.52), the variance of the effective PS II maximum quantum yield of the station was broadly similar. Maximum relative electron transport rate (rETRmax) of Porphyra blades was between $4.71{\sim}5.84(average\;5.33){\mu}mol\;electrons\;m^{-2}\;s^{-1}$, the changes of maximum relative electron transport rate (rETRmax) of Porphyra yezoensis were similar to those of PS II maximum quantum yield. Photosynthetic efficiency (${\alpha}$) was between 0.027~0.045 (average 0.036). Minimum saturating irradiance ($E_k$) range was $139{\sim}180(average\;156){\mu}mol\;photons\;m^{-2}\;s^{-1}$. Minimum saturating irradiance ($E_k$) made a difference by station within the area on southwestern coast. Carbon and nitrogen concentrations and photosynthetic rates of Porphyra blades production areas on southwestern coast were broadly similar. The photosynthetic characteristics showed low photosynthetic rates because the low maximum quantum yields and low maximum relative electron transport rate.