• 대한화학회지
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• 제57권2호
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• pp.169-171
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• 2013

• 대한화학회지
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• 제57권6호
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• pp.865-868
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• 2013

• Bulletin of the Korean Chemical Society
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• 제34권5호
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• pp.1563-1566
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• 2013

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3399-3404
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• 2013

A new accepter unit, pyrrolo[3,2-b]pyrrole-2,5-dione, was prepared and utilized for the synthesis of the conjugated polymers containing electron donor-acceptor pair for OPVs. Pyrrolo[3,2-b]pyrrole-2,5-dione unit, regioisomer of the known pyrrolo[3,4-c]pyrrole-1,4-dione, is originated from the structure of stable synthetic pigment. The new conjugated polymers with 1,4-diphenylpyrrolo[3,2-b]pyrrole-2,5-dione, thiophene and carbazole were synthesized using Suzuki polymerization to generate P1 and P2. The solid films of P1 and P2 show absorption bands with maximum peaks at about 377, 554 and 374, 542 nm and the absorption onsets at 670 and 674 nm, corresponding to band gaps of 1.85 and 1.84 eV, respectively. To improve the hole mobility of the polymer with 1,4-bis(4-butylphenyl)-pyrrolo[3,2-b]-pyrrole-2,5-dione unit, which was previously reported by us, the butyl group at the 4-positions of the N-substituted phenyl group was substituted with hydrogen and methyl group. The field-effect hole mobility of P2 is $9.6{\times}10^{-5}cm^2/Vs$. The device with $P2:PC_{71}BM$ (1:2) showed $V_{OC}$ value of 0.84 V, $J_{SC}$ value of 5.10 $mA/cm^2$, and FF of 0.33, giving PCE of 1.42%.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2769-2773
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• 2014

In this work, a new family of polyhedral oligomeric silsesquioxanes (POSS) based esters have been synthesized that consists eight ester functional groups. These are classified into Type-I and Type-II esters based on the starting materials, octakis(3-chloropropyl)silsesquioxane (Cl-POSS) and octakis(3-hydroxypropyldimethylsiloxy) octasilsesquioxane (OHPS) respectively. These new POSS type ester moieties can be used as insulating oils and oil additives in the transformers and also considered to be alternatives to mineral and vegetable oils that are presently used in the insulation system.

• Bulletin of the Korean Chemical Society
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• 제30권3호
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• pp.541-542
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• 2009

• Applied Biological Chemistry
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• 제50권3호
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• pp.217-223
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• 2007

화장품에 폴리페놀을 다량 첨가 시 색소가 문제시 될 수 있어 이를 제거하기 위하여 폴리페놀을 첨가한 토너와 에센스에 방사선을 5, 10, 20 kGy로 조사하고, 조사량에 따른 암세포증식 억제능을 검토하였다. 암세포 증식 억제능 측정 결과 모든 세포주(B16F10, G361, A549, HT-29)에 대하여 폴리페놀이 첨가된 토너와 에센스는 500 ppm에서 80% 이상의 증식 억제능을 나타내었으며, 특히 human melanoma(G361)에서는 100 ppm에서 80% 이상의 뛰어난 암세포 증식 억제 효과를 나타내었으며, 방사선 조사량이 증가해도 폴리페놀의 활성이 유지되었다. 또한, 방사선 조사량이 증가 할수록 색이 점차적으로 옅어짐을 확인할 수 있었다. 이와 같은 결과로 미루어 보아 녹차 폴리페놀을 토너와 에센스에 첨가했을 때 암세포증식 억제능이 우수하였으며, 화장품에 첨가 시 나타나는 색소문제는 방사선 조사를 이용하여 개선이 될 것으로 사료된다.

• 공업화학
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• 제27권3호
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• pp.276-279
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• 2016

본 연구에서는 항산화성분 함량이 높다고 알려진 천연물인 감잎, 엉겅퀴, 뉴그린을 이용하여 유효성분을 추출하고 DPPH radical scavening activity와 플라보노이드성분 함량분석을 수행하였다. 추출에 사용된 추출용매로는 초순수와 주정을 이용하였고, 초순수-주정의 비율, 시료의 양, 추출시간, 추출온도 등을 변수로 설정하였다. 각 천연물의 최적추출조건은 추출시간(2.5~3.5 h), 시료의 양은 50 g/L이었고, 주정/초순수의 부피비와 추출온도의 경우 각각 감잎(55~65 vol%, $50{\sim}60^{\circ}C$), 엉겅퀴(40~50 vol%, $55{\sim}65^{\circ}C$), 뉴그린(55~65 vol%, $50{\sim}60^{\circ}C$)으로 나타났다. 또한 추출된 유효성분의 항산화능과 플라보노이드성분 함량분석 결과 감잎 > 엉겅퀴 > 뉴그린 순으로 크게 나타났다.

• 한국토양비료학회지
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• 제36권2호
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• pp.92-103
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• 2003

Research and technological advances in the field of remote sensing have greatly enhanced the ability to detect and quantify physical and biological stresses that affect the productivity of agricultural crops. Reflectance in specific visible and near-infrared regions of the electromagnetic spectrum have proved useful in detection of nutrient deficiencies. Especially crop canopy sensors as a ground remote sensing measure the amount of light reflected from nearby surfaces such as leaf tissue or soil and is in contrast to aircraft or satellite platforms that generate photographs or various types of digital images. Multi-spectral vegetation indices derived from crop canopy reflectance in relatively wide wave band can be used to monitor the growth response of plants in relation to environmental factors. The normalized difference vegetation index (NDVI), where NDVI = (NIR-Red)/(NIR+Red), was originally proposed as a means of estimating green biomass. The basis of this relationship is the strong absorption (low reflectance) of red light by chlorophyll and low absorption (high reflectance and transmittance) in the near infrared (NIR) by green leaves. Thereafter many researchers have proposed the other indices for assessing crop vegetation due to confounding soil background effects in the measurement. The green normalized difference vegetation index (GNDVI), where the green band is substituted for the red band in the NDVI equation, was proved to be more useful for assessing canopy variation in green crop biomass related to nitrogen fertility in soils. Consequently ground remote sensing as a non destructive real-time assessment of nitrogen status in plant was thought to be useful tool for site specific crop nitrogen management providing both spatial and temporal information.

• 공업화학
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• 제25권3호
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• pp.233-236
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• 2014

유기발광 다이오드(Organic light emitting diodes)는 차세대 평판디스플레이로 학문적으로나 산업적으로 많은 관심을 받고 있다. 그러나 고성능 유기발광 다이오드의 생산을 위해서는 극복해야 할 많은 과제들이 여전히 남아있다. 그중 청색발광물질은 자체의 넓은 밴드갭으로 인해 녹색과 적색 발광재료에 비해 낮은 효율을 보이고 있다. 그러므로 많은 사람들이 높은 효율을 가진 청색 발광물질을 개발하기 위해 많은 노력을 기울이고 있다. 따라서 본 논문에서는 유기발광 다이오드의 기본개념과 청색 발광물질의 개발에 대해 간략하게 소개하였다.