• 한국광학회지
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• 제12권6호
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• pp.472-478
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• 2001

가변입사각 분광타원법(Variable Angle Spectroscopic Ellipsometry)을 사용하여 유기발광소자(OLED)의 발광층인 유기박막 의 광학상수와 두께를 결정하였다. 광투과영역에서 모델링분석으로 박막의 평균두께와 굴절률 분산식을 결정하고, 광흡수영역으로 확장하여 유기막의 다층구조, 각 층의 두께와 밀도 그리고 각 파장에서의 복소굴절률을 결정하였다. 분광광도계를 사용하여 구한 투과율 스펙트럼을 가변입사각 분광타원법을 사용하여 결정한 다층구조 및 복소굴절률로 계산한 투과율 스펙트럼과 비교하여 분석의 정확성을 확인하였다.

• 유기물자원화
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• 제23권3호
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• pp.23-29
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• 2015

현재 지구는 지구 온난화, 기상이변의 이상신호로 인해 전 세계적으로 자연과 인간의 상생이 중요하며, 인간의 먹거리까지 친환경 웰빙 음식에 관심이 급증한다. 우리나라는 지난 10여 년 동안 유기농업이 발전 되어왔으나 선진국에 비교해 미비하나 향후 전 세계 유기농 시장이 확대될 것이다. 2015년 세계유기농산업엑스포가 충북 괴산군에서 9월 18일부터 10월 11일 까지 개최됨에 따라 우리나라 유기농업이 발전할 것이다. 성공적이며 안전한 엑스포가 되어 안녕강국 대한민국이 되기에 일조하는 방향으로 주요 지표들을 개발하였는바, 5개 부문의 위험성 감쇄가 주안점이며, 녹색보전, 경제성장, 사회발전, 과학기술예술성, 자율자발성부문이다.

• 한국물환경학회지
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• 제34권4호
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• pp.409-422
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• 2018

The purpose of this study is to find the characteristics of organic matters based on the distribution and oxidation rates, as noted according to the spatial and temporal variations from 2008 to 2016. Generally speaking, the Han River system is separated into one lower course and two upper courses which are the Namhan River and Bukhan River. The seasonal factor is one of the most important causes of water quality changing in both of the upper courses as a result of a few pollution sources. The concentration of organic matter was measured as higher in the lower course into which great streams with point and non-point sources were identified. According to seasonal variations, however, the change of the organic matter in the lower course is comparatively slighter than that of organic matters in the upper courses. The oxidation rates related to the BOD were 15 %, 17 % and 26 % in the Bukhan River, Namhan River and the lower course, respectively. These results could be explained that more biodegradable organic matter were seen to have existed in the lower courses comparing to the activity in the upper course. The oxidation rates of the BOD were noted as relatively higher in the eutrophicated places with phytoplankton. Therefore the BOD is one of the good index models to find the characteristic of the eutrophicated water. On the other hand BOD would not be enough to estimate concentration of refractory organic matters in the Bukhan and Namhan river. Consequently, both of the TOC and BOD are necessary indices to understand the identified refractory and/or biodegradable characteristics of organic matter.

• Korean Chemical Engineering Research
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• 제53권6호
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• pp.762-769
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• 2015

직경 2~3 nm 크기를 갖는 이산화티탄 나노입자가 산성 용액에서 titanium tetraisopropoxide(TTIP)의 가수분해 반응을 조절함에 의해 합성되었다. 생성된 이산화티탄 나노입자를 졸-겔법에 의해 3-glycidoxypropyl trimethoxysilane(GPTMS)과 반응시킴에 의해 유-무기 혼성 코팅 용액이 제조되었다. 그 후 코팅 용액을 기재인 polycarbonate(PC) 시트 위에 스핀 코팅시키고, $120^{\circ}C$에서 열경화 시켜 고굴절률 하드코팅 도막이 제조되었다. 코팅 도막은 가시광선 영역에서 90%의 높은 광학적 투과율을 보였으며 2H의 연필경도를 나타내었다. 또한 코팅 용액 내의 이산화티탄 나노입자의 함량이 4%에서 25%로 증가됨에 따라 코팅 필름의 굴절률은 633 nm 파장에서 1.502로부터 1.584로 향상되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.281-281
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• 2010

Very low refractive index (<1.4) materials have been proved to be the key factor improving the performance of various optical components, such as reflectors, filters, photonic crystals, LEDs, and solar cell. Highly porous SiO2 are logically designed for ultralow refractive index materials because of the direct relation between porosity and index of refraction. Among them, ordered macroporous SiO2 is of potential material since their theoretically low refractive index ~1.10. However, in the conventional synthesis of ordered macroporous SiO2, the time required for the crystallization of organic nanoparticles, such as polystyrene (PS), from colloidal solution into well ordered template is typical long (several days for 1 cm substrate) due to the low interaction between particles and particle - substrate. In this study, polystyrene - polyacrylic acid (PS-AA) nanoparticles synthesized by miniemulsion polymerization method have hydrophilic polyacrylic acid tails on the surface of particles which increase the interaction between particle and with substrate giving rise to the formation of PS-AA film by simply spin - coating method. Less ordered with controlled thickness films of PS-AA on silicon wafer were successfully fabricated by changing the spinning speed or concentration of colloidal solution, as confirmed by FE-SEM. Based on these template films, a series of macroporous SiO2 films whose thicknesses varied from 300nm to ~1000nm were fabricated either by conventional sol - gel infiltration or gas phase deposition followed by thermal removal of organic template. Formations of SiO2 films consist of interconnected air balls with size ~100 nm were confirmed by FE-SEM and TEM. These highly porous SiO2 show very low refractive indices (<1.18) over a wide range of wavelength (from 200 to 1000nm) as shown by SE measurement. Refraction indices of SiO2 films at 633nm reported here are of ~1.10 which, to our best knowledge, are among the lowest values having been announced.

• 한국토양환경학회지
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• 제4권2호
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• pp.185-192
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• 1999

천안시의 토양 환경을 종합적으로 평가하기 위하여 각 지역별(농경지 3개소, 공단지역 3개소, 도심지 2개소, 하천주변 3개소, 매립지 주변 3개소)로 13개 항목에 관한 오염도 조사를 실시하였다. 각 측정 항목마다 토양오염 우려기준에 못 미치는 오염도를 보였다. 토양의 산성화는 농경지에서 심한 것으로 나타났으며, 특히 고속도로 주변의 농경지는 자동차 배기가스에 의한 산성 강하물의 영향으로 의심되는 산성화가 진행되는 것으로 나타났다. 또한, 밭 지역의 산성화가 심화되어서 토양 측정망의 채취지점 추가가 요구되었다. 중금속 6종과 기타 유기득성물질은 모두 토양오염 우려기준에 못 미치는 값을 나타냈다. 유류성분인 BTEX성분 역시 우려기준에 못 미치는 값을 보였으며, TPH는 BTEX보다 광범위한 오염도를 보였다. 오염물질에 의한 토양의 상태를 종합적으로 판단할 수 있도록 고안된 토양오염지표(SPI, Soil Pollution Index)를 이용하여 천안시의 토양오염도를 평가하였다. 토양오염점수(SPC, Soil Pollution Score)에 의해 산출된 토양오염 등급은 모두 1 등급으로 판명되어 천안시의 토양은 비교적 건전한 것으로 나타났다.

• 해양환경안전학회지
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• 제18권1호
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• pp.15-24
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• 2012

동해연안의 수질특성 및 상태를 파악하기 위하여 2004년부터 2010년까지의 국가해양환경측정망 조사결과를 이용하여 수질인자의 거동을 분석하였다. 본 연구에서는 통계적 방법을 이용한 수질인자간의 상관관계 및 주성분 분석을 통하여 해역별 수질환경 특성을 파악하였으며, OECD의 부영양화 기준과 부영양도, 그리고 유기오염도 지수의 산정으로 해역별 오염상태를 평가하였다. 수질인자간의 주성분 분석에서 동해연안은 클로로필 a와 염분이 주요인자로 설명되는 2개의 요인으로 구분되었다. 해역별로는 죽변을 경계로 남부와 중부로 분류되었으며, 동해 중부 해역에서는 죽변, 그리고 남부해역에서는 감포연안이 별도로 분류되었다. 동해연안의 영양상태는 Oligotrophic~Mesotrophic 수준으로 구분되었으며, 부영양화도는 1 이하로 평가되었다. 유기오염지수는 동해연안 전 해역에서 양호한 수질상태로서 평가되었다.

• Journal of Ecology and Environment
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• 제46권3호
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• pp.204-217
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• 2022

Background: Increasing land demands for food production have led to biodiversity loss and land degradation in the Madhupur Sal forest. Reforestation activities such as agroforestry and woodlot plantation support the conservation of diversity, restoration of forest and prevention of soil erosion in degraded natural Sal forest. Knowing about these reforestation activities, this study is needed to compare the species composition, richness, and soil nutrients of these two plantation activities to the natural Sal forest in the degraded Madhupur Sal forest in Bangladesh. Results: The analysis showed that in between the reforestation activities, the highest Shannon-Wiener index (1.79), evenness (0.60) and Simpson's index (0.79) were found in the agroforestry site compared to the woodlot plantation site. On the contrary, the highest species richness (n = 14), tree basal area (19.56 m² ha^-1), Margalef's index (1.96) were recorded in woodlot plantation than in the agroforestry site. We observed that at 0-15 cm depth, soil organic matter (2.39%), total nitrogen (0.14%), available phosphorous (62.67 ㎍ g^-1) and exchangeable potassium (0.36 meq/100 g) in agroforestry plots were significantly higher compared to other forest sites. At topsoil (15-30 cm depth), soil organic matter (1.67%) and available phosphorous (21.09 ㎍ g^-1) were found to be higher in agroforestry site. Conclusions: Both reforestation approaches improved soil function, although woodlot plantation had the higher species richness. Therefore, plantation activities by the sustainable implementation of these two practices are the best alternative to restore the biodiversity, richness and conserve soil fertility in the Madhupur Sal forest of Bangladesh.

• Asian-Australasian Journal of Animal Sciences
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• 제5권4호
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• pp.737-740
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• 1992

This study was conducted to demonstrate the practical use of the buffer index curve as a criterion of silage quality evaluation, Forty five samples of the ensiled Italian ryegrass were collected from farms in Okayama, Japan. Silages were devided into 4 groups by the pattern of buffer index curve. Heavy wilting silages (A group) showed no peak on buffer index curve and Flieg's score of 95.6. However, moderate or weak wilting silages (B group) with moisture content of 63.3 showed a peak at pH 4.0 and a Flieg's score of 67.8. Both of A and B groups were regarded as a good quality silage. Silages (C group) with a peak at pH 4.5 were of a medium quality with Flieg's score of 45.3. Poorly preserved silages (D group) with Flieg's score of 12.0 had a peak at pH 5.0. There was a high positive correlationship (p<0.01) between the peak value of buffer index curve and the organic acid content.

• Ocean and Polar Research
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• 제33권1호
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• pp.55-68
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• 2011

The distribution and inter-annual variation of nutrients (N, P, Si) and dissolved/particulate organic carbon were investigated in the equatorial thermocline ridge ($7^{\circ}{\sim}11.5^{\circ}N$, $131.5^{\circ}W$) of the northeast Pacific. From the Oceanic Nino Index and Multivariate ENSO Index provided by NOAA, normal condition was observed in July 2003 and August 2005 on the aspect of global climate/ocean change. However, La Ni$\~{n}$a and El Ni$\~{n}$o episodes occurred in July 2007 and August 2009, respectively. Thermocline ridge in the study area was located at $9^{\circ}N$ in July 2003, $8^{\circ}N$ in August 2005, $10^{\circ}N$ in July 2007, and $10.5^{\circ}N$ in August 2009 under the influence of global climate/ocean change and surface current system (North Equatorial Counter Current and North Equatorial Current) of the northeast Pacific. Maximum depth integrated values (DIV) of nutrients in the upper layer (0~100 m depth range) were shown in July 2007 (mean 21.12 gN/$m^2$, 4.27 gP/$m^2$, 33.72 gSi/$m^2$) and higher variability of DIV in the equatorial thermocline ridge was observed at $10^{\circ}N$ during the study periods. Also, maximum concentration of dissolved organic carbon (DOC) in the upper 50 m depth layer was observed in July 2007 (mean $107.48{\pm}14.58\;{\mu}M$), and particulate organic carbon (POC, mean $9.42{\pm}3.02\;{\mu}M$) was similar to that of DOC. Nutrient concentration in the surface layer increased with effect of upwelling phenomenon in the equatorial thermocline ridge and La Ni$\~{n}$a episode, which had formed in the central Pacific. This process also resulted in the increasing of organic carbon concentration (DOC and POC) in the surface layer. From these results, it is suggested that spatial and temporal variation of chemical and biological factors were generated by physical processes in the equatorial thermocline ridge.