• 제목/요약/키워드: rare element

검색결과 257건 처리시간 0.027초

위스콘신주 북동부 지역에 분포하는 Badwater녹암에 대한 지화학적 연구 (Geochemistry and Petrogenesis of the Badwater Greenstones from Crystal Falls Terrane in Northeastern Wisconsin, U.S.A.)

  • 위수민
    • 자원환경지질
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    • 제29권3호
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    • pp.281-291
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    • 1996
  • 위스컨신주 북동부 지역에 분포하는 Badwater녹암의 암석학적인 특정과 그들이 생성될 당시의 지구조적인 환경을 유추하기 위하여 채취한 암석을 분석하여 지화학적 연구가 행하여 졌다. 암석들의 화학조성은 전형적인 대륙성 쏠레아이트이며, Mg값이나 Ni, Cr과 같은 호정적인 원소의 함량에 미루어 분출되기전에 많은 분별정출 작용을 받았음을 시사한다. 암석들의 불호정적원소의 변화를 살펴보면 이들은 지각과의 동화작용에 많은 영향을 받았다고 사료된다. 이 암석들은 다양한 화학조성을 보이고 있으나, 모마그마의 성분과 유사한 가장 덜 분화된 암석은 전이형 해양현무암과 유사한 화학조성을 가지고 있다. 이러한 점으로 미루어 전이형 해양현무암과 화학조성이 유사한 모마그마가 지각과의 동화작용으로 그들의 화학조성이 현재의 대륙성 쏠레아이트와 같이 변하였음을 시사한다. 암석들의 지화학적 특성을 살펴보면 분기지역과 같은 인장력을 받는 지구조적 환경에서 생성된 현무암과 유사한 화학적 특징을 나타낸다.

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La-Ce 및 Sm-Nd 동위원소계 측정을 위한 란탄-레진법과 HIBA(Hydroxy Isobutyric Acid)분리법의 상호비교 (Ln-resin and HIBA Method for La-Ce and Sm-Nd Isotope Measurement)

  • 이승구;이효민;;이미정;추미경;이승렬
    • 암석학회지
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    • 제21권4호
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    • pp.431-439
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    • 2012
  • 원소의 고순도분리는 동위원소계 연구의 기초가 된다. 이 기술보고에서는 Sm-Nd 연대측정법에 중요한 원소군인 Sm과 Nd의 원소분리에 자주 이용되고 있는 HDEHP를 이용한 테플론분말(란탄-레진)법과 Sm-Nd 동위원소계 및 La-Ce 동위원소계의 연구를 위한 원소분리법인 ${\alpha}$-HIBA(${\alpha}$-Hydroxy Isobutyric acid)법의 장단점을 한국지질자원연구원(KIGAM), 기초과학지원연구원(KBSI), 극지연구소(KOPRI) 및 일본 나고야대학과 같은 각 기관별 용리곡선을 통해 비교 소개하였다. 동위원소 지구화학연구를 위한 이 고순도의 원소분리법 비교는 Sm-Nd계 및 La-Ce계 동위원소 지구화학연구자의 실험법 선택에 많은 도움을 줄 것이다.

1930년대 김종량의 H자형 한일절충식 도시주택 (Kim, Jong-Ryang's H-shaped Houses in 1930s in Seoul)

  • 백선영;전봉희
    • 건축역사연구
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    • 제18권5호
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    • pp.7-24
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    • 2009
  • This stydy investigates H-shaped houses in 1930s and examines the characters and meanigs of Kim, Jong-Ryang's H-shaped houses as a new trial to urban Hanok of those days. He, who was concerned about the housing problem of Seoul, made an attempt to make various types of dwellings. Among them, this study focuses on Japanese-Korean Style H-shaped houses in Samcheong-dong. As the alternative housing type against other urban Hanok of Seoul in 1930s, the H-shaped houses of Kim, Jong Ryang had characters as follows : 1) H-shaped houses has two special characters. First, the whole space of a single house can be divided into a left region and a right region. Second, it can be divided to a front region and a rear region. In his H-shaped houses, the left/right division was expressed as folding of space-layers in parallel with urban streets. The front/rear division was used as classification of main-living space and sub-living space. 2) KJR's H-shaped Japanese-Korean Style houses were proved to be designed as urban housing against the extreme housing shortage of Seoul in 1930s. 3) His houses however were not accepted broadly as a urban house type because the construction cost of those was higher than an average and the element of Japanese style house was not adapted to Korea. Kim, Jong-Ryang's trial is valuable because it was the rare case of realization of many discourses as defects of existing house type. With more rigorous investigations on KJR's experiment in modern house type, we could understand the housing condition of Seoul in 1930s and modern urban houses more than before.

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한국 남해 제주도 연안 퇴적물의 지화학적 특성: 퇴적물의 근원지 (Geochemical Compositions of Coastal Sediments around Jeju Island, South Sea of Korea: Potential Provenance of Sediment)

  • 임동일
    • 한국지구과학회지
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    • 제24권4호
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    • pp.337-345
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    • 2003
  • 황해 남동해역의 제주도 연안에 분포하고 있는 퇴적물의 근원지를 조사하기 위해 표층 퇴적물의 입자조직, 지화학 성분 그리고 점토광물 분석이 이루어졌다. 본 연구에서 Ti/AI, Nb/Al 그리고 Rb/Al 비 등을 포함한 특징적인 원소성분도(geochemical discrimination diagram)와 희토류 원소들의 함량 특성은 퇴적물의 근원지를 판단하는데 매우 유용한 지시자들로 제시된다. 이들 결과에 의하면, 연구해역의 세립질 퇴적물은 대부분 증국의 양자강으로부터 기원 ${\cdot}$ 운반 퇴적되었으며, 조질질 퇴적물은 주변 화산암의 풍화 잔류물인 것으로 해석된다. 창해와 동중국해에서 치근 조사된 해수의 순환 패턴과 물리-화학적 특성은 양자강으로부터 기원된 세립 퇴적물이 연구해역을 포함한 한반도 남해(황해 남동해역) 연안역까지 운반 퇴적될 수 있음을 보여준다.

집합주거단지 거주자의 인지도에 따른 이미지 분석 (The Analysis of Image by Cognitive Map of residents in apartment housing)

  • 최지희
    • 대한가정학회지
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    • 제29권4호
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    • pp.45-64
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    • 1991
  • Each of us has personal and unique "Mental Images" of environment that are the results of a two-way process between an observer and his environment. By understanding of people's image on their physical settings through cognitive maps, congruent with their design environment. In this context, this study is to fine out the characteristics of the resident's image in apartment housing that are modern housing. This paper is theoretically based on Appleyard's cognitive maps types, Lynch's the components of image, Harrison and Howard's image enhancing factors and Applyard's image enhancing factors of buildings. For the purpose of this study, two-instruments were used. One was sketch mapping, that told of visual aspects of cognitive map. Another was verbal questionnaire, which was composed of nonvisual aspects of image components and image enhancing factors. For the methods of research analysis, Percentage, Frequency, and Chi-square test were used. The results of this study are as follows. Firstly, as for the types of cognitive maps, the rate of sequential maps and spatial maps are nearly same. Secondly, as for the components of images, landmarks and districts are significant elements in apartment housing, and edges, nodes and paths are rare element. Thirdly, with regard to image enhancing factors, landscaping is shown to be most effective at landmarks and districts. And finally, in examing the differences of images between various social groups, significant variables are years of living and housing size. Age and income are the next. In this study of image, we can learn about manner in which individuals come to see, understand, and cope with the environment at a personal level. So, user-oriented approach is useful in environmental design, and particularly, it is useful in the apartment housing of the future life space.

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회남지역(懷南地域)의 옥천누층군(沃川累層群)에 분포(分布)하는 탄질(炭質) 변성이질암(變成泥質岩)의 미량(微量) 및 희토류원소(稀土類元素) 지화학(地化學) (Geochemistry of Trace and Rare Earth Elements from Coal-bearing Metapelites of the Ogcheon Supergroup at the Hoenam Area, Korea)

  • 이현구;이찬희
    • 자원환경지질
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    • 제29권6호
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    • pp.689-698
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    • 1996
  • The coal-bearing metapelites from the Hoenam area are interbedded within the Ogcheon Supergroup, which are composed mainly of graphite, quartz, muscovite and associated with trace amount of biotite, chlorite, pyrite, rutile and barite. Although the formation was mined for coal, and the contents of V, U and Mo are a higher grade in coal formations than the host metapelites. The ratios of Al/Na and K/Na in coal formation are very heterogeneous and wide range from 10.28 to 90.91 and from 3.73 to 36.60, respectively. The V content increase with increasing Al and Ba contents, but the U and Mo are not related with other elements. Those are suggested that controlled of mineral compositions in coaly metapelites due to substitution, migration and reequilibrium of elements by regional metamorphism. These coal formation were deposited in basin of marine environments and the REE of these rocks are not influenced with metamorphism and hydrothermal alterations on the basis of Al content versus La, La against Ce, the ratios of La/Ce (0.23 to 0.73) and Th/U (0.03 to 16.6). These rocks also show much variation in $La_N/Yb_N$ (0.53 to 14.19), Th/Yb (0.51 to 6.00) and La/Th (0.15 to 18.92), and their origin is explained by derivation from a mixture of sedimentary and metasedimentary rocks. The wide range in trace and REE element characteristics as Co/Th (0.07 to 3.00), La/Sc (0.04 to 23.48), Sc/Th (0.06 to 7.57), V/Ni (2 to 3319), Cr/V (0.03 to 1.06) and Ni/Co (1.00 to 79.85) of these coaly metapelites argues for inefficient mixing of the various source lithologies during sedimentation.

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주조 상태 및 용체화처리한 AZ91-4%RE 마그네슘 합금의 부식 거동 (Corrosion Behavior of As-Cast and Solution-Treated AZ91-4%RE Magnesium Alloy)

  • 한진구;현승균;전중환
    • 열처리공학회지
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    • 제31권5호
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    • pp.220-230
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    • 2018
  • The objective of this study is to investigate the effect of solution treatment on the microstructure and corrosion behavior of cast AZ91-4%RE magnesium alloy. In the as-cast state, microstructure of the AZ91-4%RE alloy was characterized by intermetallic ${\beta}(Mg_{17}Al_{12})$, $Al_{11}RE_3$ and $Al_2RE$ phase particles distributed in ${\alpha}-(Mg)$ matrix. After solution treatment, the ${\beta}$ particles with low melting point dissolved into the matrix, but Al-RE phases still remained due to their high thermal stabilities. It was found from the immersion and potentiodynamic polarization tests that corrosion rate of the AZ91-4%RE alloy increased after the solution treatment. On the contrary, EIS tests and EDS compositional analyses on the surface corrosion products indicated that the stability of the corrosion product was improved after the solution treatment. Examinations on the corroded microstructures for the ascast and solution-treated samples revealed that dissolution of the ${\beta}$ particles which play a beneficial role in suppressing corrosion propagation, would be responsible for the deterioration of corrosion resistance after the solution treatment. This result implies that the microstructural features such as amount, size and distribution of secondary phases that determine corrosion mechanism, are more influential on the corrosion rate in comparison with the stability of surface corrosion product.

Single cell heterogeneity in human pluripotent stem cells

  • Yang, Seungbok;Cho, Yoonjae;Jang, Jiwon
    • BMB Reports
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    • 제54권10호
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    • pp.505-515
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    • 2021
  • Human pluripotent stem cells (hPSCs) include human embryonic stem cells (hESCs) derived from blastocysts and human induced pluripotent stem cells (hiPSCs) generated from somatic cell reprogramming. Due to their self-renewal ability and pluripotent differentiation potential, hPSCs serve as an excellent experimental platform for human development, disease modeling, drug screening, and cell therapy. Traditionally, hPSCs were considered to form a homogenous population. However, recent advances in single cell technologies revealed a high degree of variability between individual cells within a hPSC population. Different types of heterogeneity can arise by genetic and epigenetic abnormalities associated with long-term in vitro culture and somatic cell reprogramming. These variations initially appear in a rare population of cells. However, some cancer-related variations can confer growth advantages to the affected cells and alter cellular phenotypes, which raises significant concerns in hPSC applications. In contrast, other types of heterogeneity are related to intrinsic features of hPSCs such as asynchronous cell cycle and spatial asymmetry in cell adhesion. A growing body of evidence suggests that hPSCs exploit the intrinsic heterogeneity to produce multiple lineages during differentiation. This idea offers a new concept of pluripotency with single cell heterogeneity as an integral element. Collectively, single cell heterogeneity is Janus-faced in hPSC function and application. Harmful heterogeneity has to be minimized by improving culture conditions and screening methods. However, other heterogeneity that is integral for pluripotency can be utilized to control hPSC proliferation and differentiation.

Patient-physician interaction education in Korea: a systematic review

  • Hwan Ho Lee;Yu Ra Kim;Hye Jin Park
    • Journal of Yeungnam Medical Science
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    • 제41권2호
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    • pp.74-79
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    • 2024
  • Patient-physician interaction (PPI) is an important area in medical education, but in-depth discussions on the content of the outcome of patient-doctor education are rare. Therefore, in this study, we will systematically analyze the research on PPI education in Korea. In this study, papers searched with keywords related to PPI education from Korea's academic journal service were targeted according to a systematic literature analysis method. The scope of the study was to include papers published in academic journals that are candidates for Korea Citation Index registration, excluding dissertations, research reports, posters, conference presentations, books, and internet materials. The content included papers targeting medical education and medical school students was set as the range. As a result of the analysis, although communication between PPI has many positive effects in the PPI in medical education at medical schools, obstacles do occur, and various ways to overcome them were suggested. Therefore, although medical interview training between patients and doctors in medical schools is necessary, it was analyzed as being based on overseas research or lacking in specific content. The core of PPI education appears to be medical interviews, and it seems necessary to discuss whether empathy or patient-centered medical care are appropriate as the main principles of PPI education in Korea. Therefore, education on the patient-doctor relationship is an important element in medical humanities and medical humanities education, and it is expected that research and education on this will progress more actively.

운봉지역 하상퇴적물과 압쇄상화강암류의 지구화학적 특성 비교연구 (Comparative Study on Geochemical Characteristics of Stream Sediments and Mylonitic Granites in the Unbong Area)

  • 박영석;박대우;김종균;김성원
    • 자원환경지질
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    • 제40권6호
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    • pp.727-738
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    • 2007
  • 운봉지역 하상퇴적물에 대한 지구화학적 특성규명을 통해, 주성분원소 및 미량원소에 대한 자연 배경치를 제시하고, 그 기반암(압쇄상화강암, Kim et al., 1992)과의 비교를 통해 지구화학적 재해에 대해 예견하고자 한다. 73개의 하상퇴적 물시료를 물이 흐르고 있는 1차 수계를 대상으로 채취하였고, XRD, XRF ICP-AES, NAA를 이용하여 주성분원소 및 미량성분원소를 분석하였다. 운봉지역의 주성분원소 함량은 $SiO_2\;36.94{\sim}65.39 wt.%,\;Al_2O_3\;10.15{\sim}21.77wt.%,\;Fe_2O_3\;3.17{\sim}10.90wt.%,\;CaO\;0.55{\sim}5.27wt.%,\;MgO\;0.52{\sim}4.94wt.%,\;K_2O\;1.38{\sim}4.54wt.%,\;Na_2O\;0.49{\sim}3.36wt.%,\;TiO_2\;0.39{\sim}1.27wt.%,\;MnO\;0.04{\sim}0.22wt.%,\;P_2O_5\;0.08{\sim}0.54wt.%$의 범위를 보이며, 미량성분 및 희토류원소 함량은, $Cu\;4.8{\sim}134ppm,\;Pb\;24.2{\sim}82.5ppm,\;Sr\;95.9{\sim}739ppm,\;V\;19.9{\sim}124ppm,\;Zr\;52.9{\sim}145ppm,\;Li\;25.2{\sim}3.3ppm,\;Co\;3.87{\sim}50.0ppm,\;Cr\;17.4{\sim}234ppm,\;Hf\;3.93{\sim}25.2ppm,\;Sc\;4.60{\sim}20.6ppm,\;Th\;3.82{\sim}36.9ppm,\;Ce\;45.7{\sim}243ppm,\;Eu\;0.89{\sim}2.69ppm,\;Yb\;1.42{\sim}5.18ppm$의 범위를 보인다. 주성분원소의 함량비교에서 CaO, $Na_2O,\;K_2O$ 함량은 하상퇴적물에서 기반암(압쇄상화강암류, Kim et al., 1992)인 압쇄상화강암류보다 높게 나타난다. 그리고 $Al_2O_3$$SiO_2$는 하상퇴적물과 기반암(압쇄상화강암류, Kim et al., 1992) 모두에서 높은 상관관계를 보인다. 하상퇴적물에서는 $SiO_2$ 함량이 높아질수록 희토류원소 함량도 같이 증가하는 특징을 보이나, 압쇄상화강암류에서는 $SiO_2$ 함량이 높아질수록 희토류원소 함량은 감소하는 특징을 보인다.