• Ocean and Polar Research
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• 제23권2호
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• pp.63-75
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• 2001

Species composition and community structure of the fouling found on the hulls of 28 ships traveling through 6 main shipping routes (SR)in the Far East Sea Basin were analyzed using statistical methods. Samples obtained during 1976-1990 expeditions of the Institute of Marine Biology were used for the analyses. These samples were taken from the ships anchored in the harbor by SCUBA diving and in dry-docks of the Vladivostok ship-repairing yard. Similar composition of the fouling communities occurred on the ships travelling the same SR. In five cases, fouling was dominated by different Cirripedia communities. And, in one case, a community of the mussel Mytilus trossulus was found. In most cases the results of the factor analyses showed extremely low level of the relationships among different animals and algal species in fouling communities. Each ocean-going ship had an original structure of the fouling. Spatially disconnected animal associations of tropical and boreal origin may simultaneously coexist at the same ship. This paper testified to the originality of the zone of anthropogenic substrata as a benthos concentrator in the pelagic regions of the world ocean. The fouling from different zones showed that each zone possesses peculiar features and regularities of the composition and relationships between organisms dwelling here.

• 한국항공운항학회지
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• 제28권1호
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• pp.1-6
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• 2020

The purpose of this study is to analyze the radiation dose data of the space crew of the flight crew and to present a plan for the health management of the flight crew on the basis of the analysis. The analysis show that the average exposure dose of the flight attendants continued to rise, and the exposure dose of the flight attendants was five(5) times higher than that of the radiation workers. As a way to reduce the effects of cosmic radiation, this paper suggests appropriate personnel allocation by model, balanced allocation of high and low latitude routes by crew according to the aircraft type, and a low altitude flight plan for high latitude flight. This study will help aviation crew members understand cosmic radiation and trust in the company's policies. In the future, it will be necessary to enhance the flight safety of the crew by deriving meaningful results by analyzing data related to cosmic radiation of various routes.

• Journal of Astronomy and Space Sciences
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• 제37권4호
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• pp.229-236
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• 2020

There has been increasing necessity of more precise prediction and measurements of aviation radiation in Korea. For our air crew and passengers' radiation safety, we develop our own radiation prediction model of KREAM. In this paper, we validate the KREAM model based on comparison with Liulin observations. During early three months of this year, we perform total 25 experiments to measure aviation radiation exposure using Liulin-6K in commercial flights. We found that KREAM's result is very well consistent with Liulin observation in general. NAIRAS shows mostly higher results than Liulin observation, while CARI-6M shows generally lower results than the observations. The percent error of KREAM compared with Liulin observation is 10.95%. In contrast, the error for NAIRAS is 43.38% and 22.03% for CARI-6M. We found that the increase of the altitude might cause sudden increase in radiation exposure, especially for the polar route. As more comprehensive and complete analysis is required to validate KREAM's reliability to use for the public service, we plan to expand these radiation measurements with Liulin and Tissue Equivalent Proportional Counter (TEPC) in the near future.

• 한국항해항만학회지
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• 제44권6호
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• pp.447-452
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• 2020

겨울철 온대저기압은 세력이 강하여 해양사고의 주요 원인이 되는 등 선박의 안전 운항에 있어서 매우 중요하다. 이 연구에서는 겨울철(2019년 12월~2020년 2월)의 기상 데이터를 이용하여 제1태평양한대전선대 부근의 온대저기압에 대하여 분석하였다. 분석 결과는 다음과 같다. 3개월 동안에 제1태평양한대전선대 부근에서 발생한 온대저기압은 총 41개이고, 그 중 8개가 현저히 발달하였다. 가장 강력한 온대저기압의 중심기압은 947hPa이다. 발생 위치 별 온대저기압은 일본 동쪽 태평양이 가장 많았고(16개), 그 다음은 우리나라 주변, 동중국해, 일본 남쪽 해상 순이었다. 주요 이동 경로는 크게 5가지로 구분할 수 있는데, 공통적으로 북동진하는 패턴을 보였다. 겨울철에 북태평양을 항해하는 선박이 온대저기압을 조우할 경우 선박의 최적항로는 동항 시에는 온대저기압 중심의 남측을, 서항 시에는 온대저기압 중심의 북측을 항해하는 것이다.

• Journal of Astronomy and Space Sciences
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• 제31권1호
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• pp.25-31
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• 2014

There has been a rapid increase of the concern on the space radiation effect on pilots, crew and passengers at the commercial aircraft altitude (~ 10 km) recently. It is because domestic airline companies, Korean Air and Asiana Airlines have just begun operating the polar routes over the North Pole since 2006 and 2009 respectively. CARI-6 and CARI-6M are commonly used space radiation estimation programs which are provided officially by the U.S. federal aviation administration (FAA). In this paper, the route doses and the annual radiation doses for Korean pilots and cabin crew were estimated by using CARI-6M based on 2012 flight records. Also the modeling concept was developed for our own space radiation estimation program which is composed of GEANT4 and NRLMSIS00 models. The GEANT4 model is used to trace the incident particle transports in the atmosphere and the NRLMSIS00 model is used to get the background atmospheric densities of various neutral atoms at the aircraft altitude. Also presented are the results of simple integration tests of those models and the plan to include the space weather variations through the solar proton event (SPE) prediction model such as UMASEP and the galactic cosmic ray (GCR) prediction model such as Badhwar-O'Neill 2010.

• Bulletin of the Korean Chemical Society
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• 제31권9호
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• pp.2453-2458
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• 2010

Photochemical studies of N-[(trimethylsilyl)alkyl]saccharins were carried out to investigate their photochemical behavior. Depending on the nature of the substrate and the solvent system employed, reactions of these substances can take place by either SET-promoted silyl migration from carbon to either the amide carbonyl or sulfonyl oxygen or by a N-S homolysis route. The results of the current studies show that an azomethine ylide, arising from a SET-promoted silyl migration pathway, is generated in photoreactions of N-[(trimethylsilyl)methyl]saccharin and this intermediate reacts to give various photoproducts depending on the conditions employed. In addition, irradiation of N-[(trimethylsily)ethyl]saccharin produces an excited state that reacts through two pathways, the relative importance is governed by solvent polarity and protic nature. Finally, photoirradiation of N-[(trimethylsilyl)propyl]saccharin in a highly polar solvent system comprised of 35% aqueous MeOH gives rise to formation of a tricyclic pyrrolizidine and saccharin that generated via competitive SET-promoted silyl transfer and $\gamma$-hydrogen abstraction pathways.

• Composites Research
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• 제35권4호
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• pp.298-302
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• 2022

할라이드 페로브스카이트 물질은 우수한 광전특성으로 인해 차세대 디스플레이에 응용시킬 물질로서 주목받고 있다. 본 연구에서는 다공성 SiO₂ 나노입자의 기공 내부에서 제한시킨 결정 성장을 통하여 할라이드 페로브스카이트의 안정성 문제를 해결한, CsPbBr₃의 새로운 소결법을 제안한다. 최적의 소결 조건에서 소결된 CsPbBr₃-SiO₂ 나노입자는 515 nm의 발광 피크를 나타낸다. CsPbBr₃-SiO₂ 나노입자는 소결 과정 중 닫힌 기공에 말미암아 몇 종의 극성 용매 속에서도 안정적으로 발광 특성을 유지할 수 있었으며, 이는 디스플레이용 색변환 필름으로서의 응용 가능성을 보여준다.

• 한국대기환경학회지
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• 제23권2호
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• pp.169-182
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• 2007

To evaluate the possibly potent role of Asian Dust (AD) on the long range transport of Hg, statistical analyses were carried out using the hourly concentration data of gaseous elemental mercury (Hg) along with relevant environmental parameters. For the purpose of this study, Hg data were collected from Yang-Jae monitoring station in Seoul, Korea during Sept. 1997 to June 2002. During the study period, Hg concentrations in non-AD period ranged from $0.03\;to\;32.70\;ng\;m^{-3}$ with a mean $5.27{\pm}3.06\;ng\;m^{-3}$, while those in AD period from $1.79\;to\;32.60\;ng\;m^{-3}$ with a mean $5.20{\pm}3.06\;ng\;m^{-3}$. The air quality during AD were typically deteriorated by enhanced PM10 mass concentration (by $2{\sim}5$ times) compared to non-AD period, however comparison of the Hg concentration data indicates that they are not critically distinguished between events of AD and non-AD, except for the high minimum level of Hg during AD. The results of correlation and factor analysis also indicated somewhat complex patterns; in the case of AD events, Hg and $SO_{2}$ were assorted concurrently into a same factor. Evidence collected from this study thus suggests that long-range transport of Hg, if occurring, is unlikely to raise statistically Hg concentration levels such as seen during AD event. However, in nighttime of winter season, Hg concentrations are higher during AD (along with PM10 levels) than non-AD period. Although such observations suggest the effect of long range transport on the enhancement of Hg concentrations, more deliberate analysis may be required to track down the effect of such mechanism in relation with various factors including the air mass transport route.

• 농약과학회지
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• 제3권2호
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• pp.54-59
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• 1999

제초제 metolachlor [2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)aceto-O-toluidid]의 잉어체내 행적을 구명하기 위하여 $LC_{10}$(1.93 mg/L)으로 metolachlor를 처리한 시험수에 잉어를 경시적으로 노출시켰다. 수중의 metolachlor는 잉어 체내에 신속히 흡수 이행되어 노출 후 6시간에 최대 흡수량을 나타내었으며, 잉어에 흡수 이행된 metolachlor의 주요 배설경로는 담도이었다. 또한 잉어 체내에 흡수 이행된 방사능의 추출율이 처리 후 6시간까지 현저히 감소하여 잉어 체내에서 생성된 극성 대사산물이 잉어체내에서 접합체를 형성한 후추출이 불가한 결합잔류물을 형성하였음을 시사하였다. 시험수와 잉어 추출액중 방사능이 수상으로 분배된 양이 각각 처리후 12시간과 6시간에 가장 높았고 그 양도 각각 총처리 방사능의 약 14% 및 12%로써 metolachlor가 잉어 체내에서 신속히 대사될 가능성을 시사하였다.

• 대한원격탐사학회지
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• 제34권6_2호
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• pp.1273-1282
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• 2018

최근 북극항로와 온난화 등의 영향으로 인해 북극해에 대한 활발한 연구가 진행되고 있다. 기존에 수동 마이크로파 복사계를 이용하여 북극해 해빙의 정량적 면적을 산출하는 연구는 진행되어 왔으나, 보다 고해상도로 해빙의 가장자리에서 발생하는 융해 및 표면 거칠기 변화에 대한 연구는 잘 이루어지지 않았다. 또한, 최근 Sentinel1-A/B자료가 무료로 배포되고, 특히 북극해 영역에 대한 수많은 자료들이 짧은 기간 동안 생산 및 제공되고 있기에, 이러한 대용량 자료들을 모자익(mosaic)하여 북극해 전체에 대한 고해상도 해빙정보 이용이 가능하게 되었다. 그러나 Sentienl-1A/B의 광역관측(Extended Wide, EW)모드 자료를 효과적으로 사용하기 위해서는 보다 정확한 방사보정이 수행되어야 한다. 이를 위해 이중편파 Sentinel-1A/B 자료에 나타나는 thermal noise와 scalloping 효과를 자동적으로 보정할 수 있는 방사보정 기법을 개발하였으며, 나아가 방사보정 된 이중편파 SAR자료를 이용할 경우 해빙과 open-water를 보다 더 잘 구분할 수 있음을 확인하였다.