• Journal of the Korean earth science society
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• v.42 no.1
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• pp.1-10
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• 2021

Silicon (Si) is the second most abundant element in the crust and consists of three stable isotopes, 28Si (92.23%), 29Si (4.67%), and 30Si (3.10%). Si isotopes are widely studied worldwide as a proxy for the biogeochemical cycle of Si to reconstruct the paleoenvironment and paleoclimate. However, in Korea, there have been no studies on biogenic silica using Si isotopes. In this study, we carried out Si isotope measurements of giant diatoms, summarizing the previously reported alkali fusion methods and establishing the best Si separation method for biogenic silica. Samples were completely digested using alkali fusion at high temperatures, effectively separating Si using an AG® 50W-X8 cation exchange resin. To evaluate the precision and accuracy of our measurements, Si isotope standard material (NBS-28) and USGS reference materials (AGV-2, GSP-2, BHVO-2) were analyzed. The results are in excellent agreement with the reported values within the acceptable error. The Si isotope measurement method developed in this study is expected to help in understanding the paleoclimate and paleoenvironment by tracing the Si cycle.

• Journal of Wetlands Research
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• v.26 no.1
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• pp.82-91
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• 2024

In this study, research cases related to blue carbon storage were collected and analyzed, and various definitions of blue carbon were considered in terms of spatiotemporal scope and scientific aspect. 444 papers were selected as research cases related to blue carbon storage, and analysis of the number of papers published by year/country and keywords was performed. Publication of papers related to blue carbon storage has continued to increase since 2011, and more than 50 papers have been published annually since 2018. The most publications by country were in Australia with more than 100 papers, and the United States and China also published more than 60 papers. Key terms related to "natural environment" and "storage characteristics" were analyzed in the sentences defined in the 23 papers that presented the definition of blue carbon. The natural environments where blue carbon was stored were mostly mangroves, salt marshes, and seagrass beds, and blue carbon repository included sediments and even plants themselves. The existing definition of blue carbon focused on the vegetation environment as the storage environment for blue carbon. However, since blue carbon is stored in the sediments of coastal wetlands, it would be appropriate to define the coastal ecosystem, including non-vegetated mudflats, as the storage environment for blue carbon.

• Journal of the Geological Society of Korea
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• v.54 no.6
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• pp.683-694
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• 2018

Subduction has been the focal point of numerical studies for decades because it plays an important role in the Earth's mass and energy circulations and generates earthquakes and arc volcanoes which are closely related to the human lives. Among the studies on subduction, numerical modeling has been broadly applied to the quantitative studies on the subducting slab in the mantle which cannot be directly observed. In this study, we benchmark the numerical subduction modeling using a finite element package, COMSOL $Multiphysics^{(R)}$ and the results are consistent with the previously reported benchmark results.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.3
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• pp.338-345
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• 2024

Magnetic anomaly signals from the ferromagnetic targets such as ships in the sea are measured by drone-based magnetic anomaly detection. A quantum magnetometer is suspended from the drone by 4 strings. Flight altitude and speed of drone are 100 m and 5 m/s, respectively. We obtain magnetic anomaly signals of few nT from the ships clearly. We analyze the signal characteristics by the ferromagnetic target through simulation using COMSOL multiphysics.

• Journal of the Korean earth science society
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• v.21 no.5
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• pp.635-646
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• 2000

Geological achievements of the 20th century revolutionized our views about geological understanding and concept. A good example is the concept of continental drift suggested early in the 20th century and later explained in terms of seafloor spreading and plate tectonics. Our understanding of the compositions of materials forming earth has also improved during the20th century. Radio and stable isotopes together with biostratigraphy and sequence stratigraphy allow us to interpret the evolution of sedimentary basins in terms of plate movement and sedimentation processes. The Deep Sea Drilling Project initiated in 1960s and continued as the Ocean Drilling Project in 1980s is one of the most successful international research observations, and new developments in computational techniques have provided a wholly new view about the interior of the earth. Most of the geological features and phenomena observed in deep sea and around continental margins are now explained in terms of global tectonic processes such as superplumes flowing up from the interior of our planet and interacting with such as Rodinia Pannotia and Nena back in the Precambrian time. The space explorations which began in the late 1950s opened up a new path to astrogeology, astrobiology, and astropaleontology. The impact theory rooted in the discovery of iridium and associated phenomena in 1980s revived Cuvier's catastrophism as a possible explanation for the extinctions of biotas found in the geological record of this planet. Due to the geological achievements made in the 20th century, we now have a better understanding of geologic times and processes that were too long to be grasped by human records.

• The Korean Journal of Malacology
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• v.14 no.2
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• pp.103-111
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• 1998

참굴에 다환성방향족탄화수소(PAHs)의 축적성과 이 물질들이 미치는 독성을 평가하기 위해 해양환경에서 빈번히 검출되는 PAHs 중의 하나인 fluoranthene을 사용한 모델연구를 수행하였다. Fluoranthene을 0.01-1ppm의 농도로 2주간 참굴에 노출시켰을 때 참굴 조직내의 fluoranthene의 농도는 노출기간 및 노출농도에 비례하여 최고 40-70배까지 증가하였다. 소화맹낭과 폐각근의 지질 과산화물가는 노출기간 및 노출농도에 관련하여 현저히 증가하였으며 수용성단백질의 함량은 노출기간이 길어짐에 따라 서서히 감소하였다. 그러나 glycogen 함량, nucleoside/nucleotide, DNA 및 RNA 함량은 변화하지 않았다. 이 결과로 fluoranthene은 굴의 조직내로 원활하게 축적함을 확인하였다. 또한 과산화지질의 함량은 fluoranthene에의 오염에 대해 신속히 반응하는 지표의 하나로 추정되며 수용성단백질의 감소도 비록 시간적으로 다소 둔감하기는 하나 또 다른 지표가 될 수 있을 것으로 사료된다.

• The Korean Journal of Malacology
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• v.14 no.2
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• pp.113-120
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• 1998

참굴에 다환성방향족탄화수소(PAHs)의 축적성과 이 물질들이 미치는 독성을 평가하기 위해 해양환경에서 빈번히 검출되는 PAHs 중의 하나인 anthracene을 사용한 모델연구를 수행하였다. Anthracene을 0.01-1ppm의 농도로 2주간 참굴에 노출시켰을 때 참굴 조직내의 anthracene의 농도는 노출기간 및 노출강도에 비례하여 최고 25-85배까지 증가하였다. 소화맹낭과 폐각근의 지질 과산화물가는 노출기간 및 노출농도에 관련하여 현저히 증가하였으나 수용성단백질, glycogen, nucleoside/nucleotide 및 핵산의 함량은 변화하지 않았다. 이 결과로 anthracene은 굴의 조직내로 원할하게 축적됨을 확인하였으며 과산화지질의 함량은 anthracene에의 오염에 대한 예민한 생화학적 지표가 될 수 있을 것으로 사료된다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.74-75
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• 2000

핵산의 생합성은 salvage합성이 우선되며 이 경우 섭취된 음식물유래의 핵산등이 이용되므로 섭취되는 핵산의 영양학적 가치는 매우 높다(송영정사, 1995). Van Buren이나 Kulkarni등은 mouse에의 핵산 경구투여가 면역능을 개선하여 세균감염에 대한 방어에 유효하다고 보고하였고(Van Buren C.T et al, 1983, Kulkarni A.D et a 1986), 이들의 연구가 계기가 되어 섭취 핵산의 유용성에 대한 연구보고가 계속적으로 행하여지고 있는데 그 생리활성을 살펴보면 세포부활작용(Matsunaga et al, 1987) 면역증강작용(Frederic B. Rudolph, 1994) 과산화지질 형성억제작용(Uauy R et al 1985), 장내균총 및 지질대사의 개선작용(Uauy R, 1994, Angel Gil et al, 1986)등이다 본 연구에서는 부산물로 폐기되어지는 참치정소를 이용하여 핵산복합물질을 분리·정제하는 방법 및 그 추출물의 생리활성을 연구하므로써 새로운 기능성 소재로서의 이용가능성을 탐색하였다. (중략)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.882-888
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• 1998

This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by changes in lipid components of the flounder (Paralichthys olivaceus) in the South Sea of Korea, Hemoglobin levels in serum of cultured flounders in the South Sea were lower ($4\~17\%$) than those of wild flounder in Pohang as a control group. Triglyceride (TG), Total and low density lipoprotein (LDL)-cholesterol contents in serum of cultured flounders in the South Sea were $12\~25\%,\;9\~19\%$ and $17\~25\%$ respectively which are higher than those of wild flounder in Pohang. Atherogenic index (AI) and T-Chol/PL ratios in serum of cultured flounders in the South Sea were significantly higher($26\~43\%$ and $17\~26\%$ respectively) than those of wild flounder in Pohang. These results suggest that near-coastal water as well as neritic water of the South Sea might be affected by pollutant input as well as the Yellow Sea of Korea.

• Journal of the Korean Society of Earth Science Education
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• v.9 no.3
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• pp.269-275
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• 2016

This study is conducted to search about changing earth science contents influenced by the scientific literacy from the 7th curriculum to the 2015 revised curriculum. Earth science area is divided into astronomy, geology, meteorology and oceanography contents. Among the elements of scientific literacy, the contents were analyzed focusing on STS elements. In the astronomical and meteorological content areas, there were aspects of scientific literacy in all periods from the 7th to the 2015 revised curriculum. Except for the 2007 revised curriculum in the geological area and the 7th curriculum in the oceanographic content area, the aspects of scientific literacy appeared at all times. It is emphasized the usefulness of science and technology in the astronomical content area and the use of science in everyday life in geological and meteorological content area. In the oceanographic content area, it is emphasized that content of science related social issue such as resource shortage and environmental pollution. This study can be extended to the fields of physics, chemistry and life science, we suggest to inquire the scientific literacy as a integrated science.