• 제목/요약/키워드: Marine plants

검색결과 450건 처리시간 0.025초

선박 해양용 본질안전 LED 방폭 조명 표준화를 위한 가이드 개발 연구 (A Guideline on Development of LED Convergence Intrinsic Safety Luminaire for Marine Plants & Ships and It's Standard)

  • 이승혁;김태훈
    • 대한안전경영과학회지
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    • 제19권4호
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    • pp.25-34
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    • 2017
  • Offshore plants should be managed at a high level of safety condition. Because the offshore plant has cramped space and has difficult access when a fire occurred, a fire can be critical to the plants. LED lighting can reduce the risk of fire by its lower energy consume suitable to intrinsic safety and lower heat radiation that can reduce the possibility of ignition. Also LED has a long lifetime. Though LED luminaire has various advantages for offshore plants, an international standard for the luminaire has not provided because it is new technology. Because there is no international and domestic standard specially provided for the LED luminaire, a guideline is required for developing the LED light and for the future establishment of an international standard. This study was conducted to develop the guideline for LED luminaire for offshore plants. Firstly, relevant standards were analyzed for the guideline. Then we found that there are editorial differences between international standards and domestic standards. So the guideline was developed based on international version and the differences between the domestic and international standard were provided to let Korean developers recognize the differences.

Seasonal Dynamics of Marine Benthic Communities in Intertidal Zone of Gwangyang Bay, Southern Coast of Korea

  • Yoo, Jong-Su
    • Ocean and Polar Research
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    • 제25권4호
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    • pp.519-528
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    • 2003
  • Species composition and community structure of marine benthic community were studied in the intertidal zone of Jijindo Island, Gwangyang Bay. A total of 85 species of benthic marine plants including the 5 Cyanophyta, 9 Chlorophyta, 13 Phaeophyta, 56 Rhodophyta and 2 Magnoliophyta that were listed. The community structure was represented by Gelidium divaricatum in the upper zone, Celidium divalicatum and Ulva pertusa in the middle, and Ulva pertusa, Chondria crassicaulis, Chondracanthus intermedia and Sargassum thunbergii in the lower intertidal zone. The dominant species in the rnscro-zoobenthic community were Chthamalux challengeri in the upper and middle, Littorina brevicula between the upper and middle, and Mytilus edulis and Crassostrea gigas in the middle and lower intertidal zones. The economic benthic organisms such as Undaria pinnatifida, Mytilus edulis, and Crassostrea gigas found in the lower intertidal zone were frequently disturbed due to their collection by local resident. Therefore, it is necessary to record the correct information pertaining to these cases. The species diversity indices estimated kom different sources were quite different. They were 2.22 derived from frequency, 1.67 based on coverage, 2.17 based on sum of frequency and coverage and 2.04 derived from importance value. Species diversity and number of algal species in Gwangyang Bay have noticeably decreased, compared with their previously reported status. It is estimated that their decreases were caused by changes in the marine environment, especially pertaining to the polychaete community resulting from reclamation and dredging activity undertaken for the industrial development.

Radioactivity data analysis of 137Cs in marine sediments near severely damaged Chernobyl and Fukushima nuclear power plants

  • Song, Ji Hyoun;Kim, TaeJun;Yeon, Jei-Won
    • Nuclear Engineering and Technology
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    • 제52권2호
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    • pp.366-372
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    • 2020
  • Using several accessible published data sets, we analyzed the temporal change of 137Cs radioactivity (per unit mass of sample) in marine sediments and investigated the effect of the water content of sediment on the 137Cs radioactivity, to understand the behavior of 137Cs present in marine environments. The 137Cs radioactivity in sediments decreased more slowly in the Baltic Sea (near the Chernobyl nuclear power plant) than in the ocean near the Fukushima Daiichi nuclear power plant (FDNPP). The 137Cs radioactivity in the sediment near the FDNPP tended to increase as the water content increased, and the water content decreased at certain sampling sites near the FDNPP for several years. Additionally, the decrease in the water content contributed to 51.2% of the average 137Cs radioactivity decrease rate for the same period. Thus, it may be necessary to monitor both the 137Cs radioactivity and the water content for marine sediments to track the 137Cs that was discharged from the sites of Chernobyl and Fukushima nuclear power plants where severe accidents occurred.

일본의 원전 오염수 방류가 국내 수산물 소비에 미치는 영향 분석 : 설문조사 결과를 중심으로 (An Analysis of the Impact of Japan's Contaminated Water Release from Nuclear Power Plant on Korean Consumption of Seafood - Focused on Survey Results)

  • 윤유진;김은경
    • 수산경영론집
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    • 제53권2호
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    • pp.58-72
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    • 2022
  • Fishery products play an important role in Korean food culture, and awareness of the safety of fishery products is increasing in the seafood market. Against this backdrop, Japan has announced a plan to release radioactive water to the sea from 2023. In the case of Korea, it is adjacent to the area to be discharged, so there are concerns about securing the safety of marine products. Therefore, it is necessary to analyze the change in perception and impact of marine product consumers due to the discharge of contaminated water and to study appropriate countermeasures when discharging contaminated water from nuclear power plants. In this study, the current status of radioactive contaminated water discharge in Japan was summarized, and a survey was conducted on the change in the consumption perception of marine products according to the discharge of contaminated water to analyze the factors affecting the consumption change of domestic consumers. According to the survey, 85.3% of the respondents said that it will affect the purchase of domestic marine products if Japan starts discharging contaminated water from nuclear power plants. Moreover, 85.5% of the respondents said it will affect the purchase of imported marine products.

마이크로프로세서를 이용한 인터넷 원격감시제어 시스템에 관한 연구 (A Study on a Internet Remote Control and Monitoring System using a Microprocessor Embedded Controller)

  • 서인호;유영호
    • Journal of Advanced Marine Engineering and Technology
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    • 제25권4호
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    • pp.869-879
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    • 2001
  • Serial communications such as RS-232C or RS-485 have been used to control and monitor the industrial plants for a long in cooperating with a computer or microprocessor. In recent years a great deal of effort has been made to achieve these control and monitoring through Internet network. This paper proposes a microprocessor system to implement remote control and monitoring system through Internet network. The proposed system uses NE2000 compatible NIC for data link and physical layer to access Internet network The microprocessor employed in the system plays a role of interfacing NE2000 compatible NIC interpreting protocols above link layer, controlling and monitoring industrial plants simultaneously. This paper also shows MMI and experimental results which control and monitor two power plants on the computer monitor with a mouse remotely to verify the proposed.

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부산 서암 조간대 부착생물군집의 동태 (Dynamics of Marine Benthic Community in Intertidal Zone of Seoam, Busan)

  • 유종수
    • 한국해양학회지:바다
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    • 제8권4호
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    • pp.420-425
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    • 2003
  • 부산 서암 조간대 부착생물군집의 종조성, 군집구조, 종다양성을 조사하였다. 부착해산식물의 출현종수는 남조류 4종, 녹조류 6종, 갈조류 17종, 홍조류 47종, 해산종자식물 l종으로 총 75종이 관찰되었다. 부착해산식물 우점종은 melobesioidean algae, Chondracanthus tenellus, Sargassium thunbergii, Corallina spp., Phyllospadix japonica 5 종이었고, 여름에 Ulva pertusa가 추가되는 경향을 보였다. 저서동물은 Chthamalus challengeri and Mytilus edulis 가 조간대 상부와 중부에 우점하는 단순한 분포를 보였다. 한편 해조군집의 종다양성지수는 빈도, 피도, 빈도와 피도 합 그리고 중요도를 기준으로 계산한 결과, 각각 1.81, 2.25, 2.19, 1.80로 나타났다. 이는 종다양성지수의 계산을 위한 기준자료에 따라 값이 달라짐을 의미하는 것으로, 차후 종다양서지수를 논할 때 기본자료 선택의 중요성과 방법론의 표준화가 필요함을 지적한 것이다. 한편 본 연구에서 분류된 해조류 종수는 부산연안에서 기 조사된 결과와 비교할 때 최고 65%까지 감소한 것으로 나타났다.

Laser Peening: A Novel Tool to Reduce SCC Susceptibility and Prolong Fatigue Life of Metallic Components

  • Sano, Yuji;Kim, Jong-Do
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권5호
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    • pp.661-669
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    • 2010
  • The effects of laser peening on metallic materials have been investigated with water-penetrable frequency-doubled Nd:YAG laser. Laser pulses of 200 mJ energy and 8 ns duration focused on samples underwater with 0.8 mm spot diameter. X-ray study showed that compressive residual stress was imparted on SKD61 from the surface to nearly 2 mm depth. Stress corrosion cracking (SCC) was prohibited for sensitized SUS304 even in a severely corrosive environment fatigue lives of SUS316L and SM490A welded samples were prolonged significantly in the high-cycle regime. Since 1999, laser peening has been applied to prevent SCC in operating nuclear power plants in Japan.

한국산 해산식물의 추출물로부터 Aldose Reductase 억제활성의 검색 (Screening for Aldose Reductase Inhibitory Activity of Extracts of the Marine Plants from Korea)

  • 이연실;이상현;김박광;신국현
    • ALGAE
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    • 제19권4호
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    • pp.349-352
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    • 2004
  • We examined MeOH extracts of the marine plants from Korea for their inhibitory activities on rat lens aldose reductase in vitro. Among the MeOH extracts tested, the extracts of Enteromorpha prolifera, Ecklonia cava, Pelvetia siliquosa and Salicornia herbacea exhibited a rat lens aldose reductase inhibition (IC$_{50}$: 3.04, 8.84, 11.42 and 4.99 $\mu$g-ml$^{-1}$, respectively) in vitro.