• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.320-325
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• 2012

The catalytic cracking of waste lubricant oil was carried out on silica-alumina (SA), hydrogen-type mordenite (HM), and dealuminated mordenite (DM) with the silica/alumina ratio of 10.5, 10, and 12.5, respectively. Activity in the catalytic cracking was found to be in the order of SA > DM > HM. Carbon number distribution of the oil obtained over SA was similar to that of gasoline while that of the oil obtained over DM was similar to that of diesel. Carbon number distribution of the oil obtained over HM was similar to that between gasoline and diesel. Acid amounts of three kinds of catalysts were found to be in the order of $SA\;{\approx}\;HM$ > DM. Unlike HM and DM with pores of an uniform diameter below 10 A, SA had a pore size distribution within the range of 10 to 50 A. These results indicate that the acid amount and pore size of the catalysts may be related to the carbon number distribution of the cracked oil. The decrement of surface area by the accumulation of carbon and impurities on the surface of the catalyst was found to be in the order of SA > DM > HM.

• Ocean and Polar Research
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• v.36 no.2
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• pp.111-119
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• 2014

This study examined the spatial and temporal variation of dissolved inorganic radiocarbon in the East Sea. Five vertical profiles of radiocarbon values were obtained from samples collected in 1999 in three basins (Japan Basin, Ulleung Basin, Yamato Basin) of the East Sea. Radiocarbon values decreased from 63- 85‰ at the surface to about -50‰ with increasing depth (up to 2,000 m) and were nearly constant in the layer deeper than 2,000 m in all basins. Radiocarbon values did not show significant basin-to-basin differences in the surface and the bottom layers. In the intermediate layer (200-2,000 m), however, they decreased in the order of Japan Basin > Ulleung Basin > Yamato Basin, which is consistent with the suggested circulation pattern in the intermediate layer of the East Sea. Radiocarbon was found to have decreased at ~2%/year in the surface water of the East Sea. In contrast, in the interior of the East Sea, radiocarbon values have increased with time in all three basins. In the Central Water, the annual increase rate was about 3.3‰, which is faster than the rates in the Deep and Bottom Waters. The radiocarbon in the Deep and Bottom Waters had increased until mid-1990s, after which time it has been almost constant.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.227-227
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• 2003

흑연(graphite), 석탄(coal), 숯(char), soot(검댕이) 등의 탄소로 이루어진 재료들은 비정질부터 완전한 흑연결정까지 다양한 구조를 나타낸다. 이러한 탄소재료의 구조의 출발물질 뿐 아니라 열처리에 따라 강한 영향을 받는다 이러한 구조는 여러 구조인자에 의해 특성화되는데, 구조인자로는 층간거리 d, 결정립 크기 Lc 그리고 결정립 직경 La이다. 이런 구조 인자의 지식은 흑연화, 탄소화, 가스화 등과 같은 다양한 공정을 이해하는데 매우 중요하다. 많은 연구자들은 XRD, Raman 분광, 고분해능 TEM 등과 같은 여러 기술을 통하여 이러한 구조인자에 대한 해석을 시도하였다. 그 중 XRD는 정량적 분석에 있어서 가장 많이 이용되는 기술이다. XRD 회절피크의 위치로부터 층간거리 d를 구할 수 있으며, 결정립 크기 Lc 및 결정립 직경 La는 피크의 line 퍼짐(반가폭)으로 직접 구할 수 있다. 한편 섬유상 흡착제로 이용되는 등방성 탄소섬유는 이산화탄소 또는 수증기에 의해 쉽게 활성화되어 최고 약 2,500 $m^2$/g의 고 비 표면적을 얻을 수 있다. 이렇게 활성화 후 고 비표면적을 나타내는 이유는 좁은 분포를 나타내는 미세기공의 기공구조 때문에 발생하는 것으로 알려져 있다.

• Journal of the Korean Data and Information Science Society
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• v.27 no.4
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• pp.1001-1012
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• 2016

It is well known that air pollutants exert a bad influence on human health. According to the United Nations Environment Program, 4.3 million people die from carbon monoxide and particulate matter annually from all over the world. Carbon monoxide is a toxic gas that is the most dangerous of the gas consisting of carbon and oxygen. In this paper, we used 1 hour, 6 hours, 12 hours, and 24 hours average carbon monoxide concentration data collected between 2004 and 2013 in Daegu Gyeongbuk area. Parameters of the generalized extreme value distribution were estimated by maximum likelihood estimation and L-moments estimation. An evalution of goodness of fitness also was performed. Since the number of samples were small, L-moment estimation turned out to be suitable for parameter estimation. We also calculated 5 year, 10 year, 20 year, and 40 year return level.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.576-581
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• 2008

High-quality double-walled carbon nanotubes (DWNTs) were synthesized without defects and amorphous carbonaceous particles by catalytic decomposition method at $800^{\circ}C$ in high yield. As-synthesized carbon materials almost consist of DWNT bundles with a diameter 12 - 20 nm.. The DWNTs rope have uniform diameter about 2 - 5 um and length up to several tens micrometer. DWNTs is inner tube diameter 0.9 - 1.5 nm and outer tube 1.6 - 2.2 nm. We investigate the crystallinity of DWNTs by TEM and Raman spectroscopy. We also found that the Fe-Mo bimetallic catalyst was active as a very efficient catalyst for the synthesis of DWNTs with the catalyst decomposition method. Our results also indicate that Tetra Hydro Furan (THF) is a very ideal carbon source for the synthesis of DWNTs.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.3
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• pp.124-131
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• 2008

This study was conducted around the southwest sea areas of Jeju and coastal sea areas of China in August 2003 and September 2004 to research distribution patterns of dissolved inorganic nutrients, dissolved and particulate organic carbon. Distribution patterns of nutrients in the East China Sea in summer were shown to be influenced by water masses and phytoplankton. Water masses in the East China Sea in summer, except for coastal sea areas of china, showed less vertical mixing process, causing decline in the inflow of nutrients to surface water. Bottom water, however, showed high concentration, since nutrients made by dissolved organic matters from surface water were accumulated at the bottom. Sea areas with high concentration of chlorophyll a showed low concentration of nutrients and vice versa, indicating biological activities control dissolved inorganic nutrients. The distribution of dissolved organic carbon didn't show any correlation with salinity, temperatures, and water masses. Areas around the river mouth of the Changjiang showed high concentration of dissolved organic carbon more than $100{\mu}M$, but relatively low concentration in the southwest sea areas of Jeju, indicating that the river mouth of the Changjiang coastal water has a great influence on dissolved organic carbon in the East China Sea. Distribution patterns of particulate organic carbon in the research areas showed the highest concentration of average $9.23{\mu}M$ in coastal areas of China influenced by the river mouth of the Changjiang coastal water. By comparison, the concentration was relatively low at $3.04{\mu}M$ in the southeast sea areas of Jeju on which the Taiwan warm current has influence, and was $7.23{\mu}M$ in the central sea areas of Jeju. Thus, there is much indication that the river mouth of the Changjiang coastal water serves as a supplier of particulate organic carbon along with autogenous source. In general, if particulate organic carbon has a high correlation with the concentration of Chlorophyll a, it is thought that it is originated from autogenous source. However, the southeast sea areas of Jeju shows low salinity below 30, therefore it is proper to think that its origin is terrestrial source rather than that of autogenesis.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2007.10a
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• pp.221-225
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• 2007

산림은 탄소저장능력이 있어 대표적인 온실가스인 이산화탄소를 저감시킨다. 따라서 산림의 탄소저장능력 특성을 규명하고 그것을 산림경영에 반영함으로써 온실가스 저감이라는 국제적 노력에 동참하는 수단으로 활용할 수 있다. 일반적으로 임분에서의 탄소저장능력(Carbon Storage, CS)은 식생탄소저장능력(Vegetation Carbon Storage, VCS)과 토양탄소저장능력(Soil Carbon Storage, SCS)의 합으로 볼 수 있다. 본 연구에서는 우리나라 대표적인 자생수종인 소나무림 VCS의 공간분포를 지엽적 범위(spot level)에서 광역적 범위(regional level)로 확대하여 그 특성을 규명하는 방법을 제시하고자 한다. 지엽적 범위의 조사 및 연구에서 VCS는 임목의 흉고직경(Diameter at Breast Height)과 밀접한 관계가 있는 것으로 확인되었다. 이러한 관계와 Quickbird 고해상도 위성영상에서 추출한 소나무림 공간분포도를 이용해 경관범위(landscape level)에서 소나무림 탄소저장능력의 공간분포를 추정할 수 있었으며,그 결과를GIS 및 RS를 통해 광역적 범위로 확대하였다.

• Journal of Korean Society of Forest Science
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• v.103 no.2
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• pp.264-269
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• 2014

The aim of this study was to determine the current distribution area of Robinia pseudoacacia habitat and to estimate its stand yield as well as its carbon stocks. In order to do so, the area of R. pseudoacacia distribution is obtained based on the large-scaled forest type map (1:5,000). Also, Weibull diameter distribution model is used to predict the yield of R. pseudoacacia stands. In addition, carbon emission factor is applied to calculate carbon stocks and removals. To obtain the stand yield of R. pseudoacacia, we developed estimation equation considering growth factors of the stand, e.g. mean diameter, the basal area, maximum and minimun diameter and etc. and tested it to ensure accuracy. Consequently, estimation equation derived from all growth factors have shown significance that could also be used for analysis. Site index was also established to determine the productivity of the forestland that later turned out to be ranging from 16 to 22. Based on these results, stand yield tables were drawn up. R. pseudoacacia is widely distributed in inland areas of Gyeongsang, Chungcheong and Gyeonggi provinces which covers total area of 26,770 ha. And when it is converted into carbon stocks, it amounts to 2,517,598tC with annual carbon uptake of 3.76tC/ha which is comparable to Querqus species that is known to storer large amounts of carbon. Therefore, R. pseudoacacia is also expected to serve as a viable carbon pool that would contribute to the mitigation of climate change. Furthermore, stand yield tables, an outcome of this survey would assist not only in proper management but also in sustainable management policy of R. pseudoacacia.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.39-39
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• 2022

최근 전 지구적인 기후변화로 인하여, 극한기후일수 증가, 이상기후 등의 환경문제가 심화되고 있으며, 이는 이·치수 측면에서 물관리 정책 수립 등의 어려움을 가중시키고 있다. 더욱이 우리나라는 산악지형이 많고 수계형태가 복잡한 지형적 특성과 여름철에 연강수량이 집중되는 계절적 특성을 지니고 있어 수자원의 효율적인 관리가 어려운 실정이다. 연구 대상 유역은 DMZ 이북의 미계측 유역을 포함한 북한강 전체유역을 대상으로 하였으며, 주요 댐 유역별로 세분하여 6개 댐유역(화천댐, 춘천댐, 소양강댐, 의암댐, 청평댐, 팔당댐)에서 홍수량 분석을 실시하였다. 이때 상류의 미계측 유역을 분석하기 위해 격자기반으로 매개변수의 물리적인 계산이 가능한 분포형 모형인 GSSHA 모형을 활용하였다. 또한 온실가스 저감 정책의 실현 여부에 따른 저탄소 및 고탄소 기후변화 시나리오를, 미래 전·중·후반기의 기간별로 적용하여, 현재를 포함한 7가지 시나리오를 반영하였다. 연구결과, 미래 전반기에서는 홍수량이 다소 감소하는 것으로 나타났으며 미래 중반기 및 후반기에서는 증가하는 것으로 분석되었다. 소유역별 분석 결과를 종합하면, 탄소 배출 농도에 따른 평균 홍수량 변화율은 저탄소 시나리오에서는 -1.03 %에서 +4.01 %, 고탄소 시나리오에서는 -4.54 %에서 +17.73 %로 나타났다. 저탄소와 고탄소 시나리오를 비교하면 홍수량 변화율 차이는 미래 기간 및 소유역 마다 상이하지만, 최소 359 %에서 최대 527 %까지 차이를 보였다. 따라서 인류의 탄소저감 노력은 기후변화 자체를 막을 수는 없으나, 그 영향을 최대 5배 이상 감소할 수 있다는 결론을 도출하였다. 본 연구는 북한강 유역의 미래 기간별 확률홍수량 예측값 및 수문특성의 변화 전망을 주요 댐 유역에서 정량적으로 제시하였다. 이에 따라 본 연구가 향후 기후변화에 대비한 이·치수 정책 마련 및 접경지역의 재난예방에 기여할 수 있을 것으로 기대된다.

• The Korean Journal of Pain
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• v.6 no.1
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• pp.74-82
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• 1993

신선한 소의 대뇌피질로부터 synaptosomal plasma membrane vesicles(SPMV)를 분리하고 이 SPMV로부터 추출한 총지질(cholesterol과 각종 인지질 함유)로서 제제한 인공세포막(SPMVTL)에서의 n-alkanols 침투 정도를 형광 probe를 이용한 형광 소광법을 통하여 검색하였다. n-alkanols는 SPMVTL 외부 단층(outer monolayer)의 표면에 주로 분포하되 그 탄소수에 비례하여 소수성 부위에 분포되는 양이 증가되는 경향을 나타내었다(1-decanol은 예외). Methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-hepatnol, 1-cotanol, 1-nonanol 및 1-decanol은 SPMVTL 외부 단층 표면(친수성 부위)에 분포되는 것이 소수성 부위에 분포되는 것에 비하여 각각 650, 288, 151.6, 69.5, 36.8, 11.9, 4.8, 1.6, 0.74, 2.1배가 된다는 것을 확인하였다. 1-decanol은 $C_{10}$인데도 불구하고 $C_8$인 1-octanol에 비하여 적은 양이 소수성 부위에 침투 분포되는 것이 확인되었다. 또한 n-alkanols는 저자등이 이미 보고한 SPMV에서의 경우보다도 본 연구에서의 SPMVTL의 경우가 현저하게 많은 양이 소수성 부위로 침투 분포된다는 것이 확인되었다.