• 한국환경농학회지
• /
• 제38권4호
• /
• pp.225-236
• /
• 2019

인공광 식물공장에서는 작물을 생산하기 위하여 일반적으로 화학비료 유래 무기성분을 포함하는 배양액을 시용하여 수경재배한다. 본 연구에서는 광질이 상이한 식물공장에서 관행의 무기배양액 일부 또는 전량을 유기배양액으로 대체할 수 있는 폐기 농업부산물 유래 유기배양액을 시용하여 수경재배하고 작물의 생장에 미치는 영향을 검토하였다. 청색, 적색 및 백색 LED를 1:2:1의 비율로 혼합한 혼합LED 및 관행의 형광등 조사 조건에서 적치마와 청치마 상추 실생묘를 35일간 수경재배한 결과, 적치마와 청치마 상추의 생체중 및 전개엽수 증가는 형광등을 조사한 Y구에서 통계적으로 유의하게 증가하였다. 그러나 유·무기 혼합배양액 처리구인 YK 및 YTJ에서는 오히려 혼합LED 조사구에서 증가하였다. 유기배양액 단용 또는 유·무기 혼합배양액 처리시 엽내 SPAD치는 두 실생묘 모두 Y구와 유사하거나 증가하는 경향을 나타내었다. 관행의 무기배양액인 Y구에서 배양액내 구성성분 중 가장 많은 양을 차지하고 있는 무기성분인 NO₃-N은 재배 개시일에 약 97 mg/L으로, 적치마와 청치마 상추 실생묘에서 모두 재배기간이 경과함에 따라 감소하는 경향을 보였다. 적치마의 경우 재배종료시 각 처리구별 NO₃-N 농도는 형광등 조사시 약 29 mg/L, 혼합LED 조사시 24 mg/L였으며, 청치마의 경우 형광등 조사시 약 26 mg/L, 혼합LED 조사시 47 mg/L로, 초기 투입량 대비 25~48% 정도의 양이 재배종료시까지 흡수되지 않고 남아 있었다. 재배개시일 NH₃-N 농도는 Y구3-N 잔여량은 약 13%로 최대값을 나타내었다. 관행의 무기배양액내 질산태질소는 작물체에 흡수되어 생체중, 엽수 증가와 같은 지상부 생장을 좌우하는 주요 성분이지만 재배종료시까지 전량이 흡수되지 않고 남아 있는 것으로 보아 상추 수경재배시 배양액내 질산태질소의 초기 투입량을 조절할 필요성이 대두되었다. 연구결과 농업부산물 유래 유기배양액을 활용하여 적치마와 청치마 상추를 수경재배할 경우 유기배양액 단용보다 유·무기 혼합배양액 시용으로 유기배양액내 부족한 질소 성분을 무기질소로 보충할 수 있어 무기성분 사용량 저감이 기대된다. 또한 상추 실생묘의 양적생장 추이와 달리 엽내 색소합성이 관행 무기배양액보다 특정 유기배양액 단용 또는 혼용에 의해 유의하게 증가하는 것으로 보아 작물체내 물질합성량, 유기배양액 사용기간 및 재이용 등 유기배양액의 화학적 특성 변화에 대한 연구가 필요할 것으로 판단된다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
• /
• pp.588-591
• /
• 2004

Polyazomethine type conjugated copolymers containing phenanthridine units, poly(PZ-PTI), were synthesized by Schiff-base reaction. This new conjugated copolymer exhibited improved solubility in common organic solvents due to the presence of alkyl side chains as well as phenanthridine groups. Double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) light emitting diode (LED) exhibited enhanced EL emission and efficiency compared to that of single layer (ITO/poly(PZ-PTI)/Mg) LED. With increasing the thickness of $Alq_3$ layer in double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) LED the emission peak gradually shifted to the single layer (ITO/$Alq_3$/Mg) LED, confirming good hole transporting behaviour of the synthesized conjugated copolymer.

• 한국결정성장학회지
• /
• 제11권5호
• /
• pp.207-210
• /
• 2001

Metal-organic VPE (MOVPE) epitaxial growth procedure and related device fabrication technique are reported for GaInP-based epitaxial materials and devices. For GaInP/GaInAs two-dimensional electron-gas field-effect transistor (TEGFET), a promising epitaxial stacking structure resulting in enhanced electron mobility is given. In conjunction with this, a new device fabrication technique to improve luminous intensity of GaInP-based LED is also shown.

• 멤브레인
• /
• 제7권1호
• /
• pp.22-30
• /
• 1997

Porous asymmetric membranes were prepared from polyetherimide polymer by the phase-inversion technique under different conditions. The performance of the membranes was tested for the removal of acetone vapour from nitrogen. A membrane which showed a high acetone permeability and a high selectivity was chosen and tested further for the separation of different organic vapours from nitrogen. The molecular structure of organic vapours and the selectivity were correlated. A strong correlation was also found between the chromatographic retention time of the organic vapour and the selectivity. These experimental results led to the conclusion that the sorption is the factor governing the separation of volatile organic compounds from nitrogen. A membrane was also prepared by coating the surface of a porous polyetherimide membrane with silicone rubber. The performance of membranes with and without silicone rubber coating was compared.

• 농업과학연구
• /
• 제50권4호
• /
• pp.967-976
• /
• 2023

Biochar is emerging as a promising substance for achieving carbon neutrality and climate change mitigation. It can absorb several nutrients via ion bonding on its surface functional groups, resulting in slow dissociation of the bonds. Biochar, like organic fertilizers, contributes to sustainable nutrient management. The purpose of this study was to investigate the effects of nutrient-coated biochar amendments on leafy vegetables production and soil fertility. The nutrient-coated biochar was produced by soaking rice husk biochar in a nutrient solution containing nitrogen (N), phosphorus, and potassium for 24 hours. Nutrient-coated biochar and organic fertilizers were applied to soil at a rate of 120 kg·N·ha^-1. The growth components of the leafy vegetables showed that nutrient-coated biochar led to the highest fresh weight (FW) of both lettuce and kale (i.e., 146.67 and 93.54 g·plant^-1 FW, respectively). As a result, nutrient-coated biochar amendments led to superior yield compared to the control treatment and organic fertilization. The elemental composition of leafy vegetables revealed that soil amended with nutrient-coated biochar resulted in higher nutrient contents, which was attributed to the high nutrient contents supplied by the rice husk biochar. Soil amendment with nutrient-coated biochar positively enhanced the soil fertility compared to amendment with organic fertilizer. Therefore, nutrient-coated biochar is a promising substance for enhancing agronomic performance of leafy vegetables and improving soil fertility.

• Environmental Engineering Research
• /
• 제15권1호
• /
• pp.9-14
• /
• 2010

The objective of this study was to assess the variation in the concentration of assimilable organic carbon (AOC) in a drinking water resource, and investigate the characteristics of AOC derived from algae. The seasonal change in AOC at the Kamafusa dam corresponded to changes in the algal cell number. In order to understand the relationship between AOC and algae in a water resource and water purification plant, two kinds of laboratory experiment were performed. The algal culture experiment showed that extracellular organic matter (EOM) that was released during the growth of Phormidium tenue with M-11 medium led to significant increases in the AOC concentration, but no significant variation in the AOC concentration was observed with CT medium containing a high dissolved organic carbon concentration. The chlorination experiment showed that the AOC included in EOM was not easily removed by chlorination, although the AOC included in intercellular organic matter released from the algal cells by chlorination was removed under conditions where residual chlorine was detected.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.185-188
• /
• 2008

We have analyzed the structures of $Alq_3$ in different polymorphs by solid-state NMR. On the basis of the results, OLEDs were fabricated from different polymorphs of $Alq_3$. The current efficiency of the device fabricated from the mixture of $\alpha$-, $\gamma$-, and $\delta-Alq_3$ powders was higher than that from $\alpha-Alq_3$.

• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
• /
• pp.1513-1515
• /
• 2008

High efficiency phosphorescent organic light emitting devices ($PHOLED^{TM}s$) are now widely used in commercial displays. In this paper we describe some of the work behind the development of high efficiency stable green PHOLEDs capable of fulfilling display specifications.

• 한국신뢰성학회지:신뢰성응용연구
• /
• 제9권2호
• /
• pp.131-148
• /
• 2009

An organic light emitting diode (OLED), also light emitting polymer (LEP) and organic electro luminescence (OEL), is any light emitting diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple "printing" process. The resulting matrix of pixels can emit light of different colors. Such systems can be used in television screens, computer displays, small, portable system screens such as cell phones and PDAs, advertising, information and indication. OLEDs can also be used in light sources for general space illumination, and large-area light-emitting elements. In this paper, we develop the general guide line of the accelerated life test for assuring B10 life of AMOLED(Active Matrix Organic Light Emitting Diode) and PMOLED(Passive Matrix Organic Light Emitting Diode) which are widely used for display monitor less than 115 mm.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.249-249
• /
• 2011

투명전도성산화물(transparent conducting oxides, TCOs) 박막은 전기 전도성과 광투과성이 우수하여 유기발광다이오드(organic light-emitting diode, OLED), 태양전지(solar cell), 발광다이오드(LED) 등의 광전자 소자에 널리 응용되고 있다. 특히 LED에서 p-GaN층에서 전류가 층안에서 충분하게 확산되지 않기 때문에, TCO는 균일하게 전류를 흘려보내기 위해서 전류확산층(current spreading layer)으로 사용된다. 그 중 널리 쓰이는 산화인듐주석(indium tin oxide, ITO)은 고가의 indium가격과 인체에 유해한 독성 등이 문제점으로 지적되고 있다. 따라서 indium의 함량을 저감하거나 함유하지 않은 새로운 조성의 친환경적 대체 TCO 개발에 대한 연구가 많이 진행되고 있다. 이러한 반도체 재료 중 하나인 AZO (Al-doped zinc oxide, Al2O3 : 2wt.%)는 3.3 eV의 넓은 에너지 밴드갭을 가지며, 가시광선 및 근적외선 파장영역에서 높은 투과율을 나타낸다. 따라서 본 연구에서는 GaN기반 LED 응용을 위한 전류확산층으로 ITO 대신 AZO의 특성을 연구하였다. 박막 증착율이 높고, 제작과정의 조정이 용이한 RF magnetron 스퍼터를 이용하여 glass기판 위에 AZO, Ni/AZO, NiOx/AZO를 증착하였다. 이어서 $N_2$ 분위기에서 다양한 온도 조건에서 열처리(rapid thermal annealing, RTA)하여 전기적 광학적 특성에 대하여 비교 분석하였다.