• 제목/요약/키워드: Cr-Ni 강

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영산강 수계 표층 퇴적물의 금속류 분포 및 오염도 평가 (Assessment of Heavy Metal Pollution in Surface Sediments of the Yeongsan River)

  • 양해종;강태우;봉기문;정효진;양원준;한종학;정희정;황순홍;김경현
    • 환경분석과 독성보건
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    • 제21권4호
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    • pp.292-303
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    • 2018
  • The particle sizes and heavy metal concentrations (Pb, Zn, Cu, Cd, Hg, As, Cr, Ni, Li, Al) of surface sediments of the Yeongsan River were analyzed to assess the distribution and pollution level of heavy metals. The distribution of particle sizes was dominated by sand in the upstream sites (MS1-MS7) and by silt loam in the downstream sites (MS8-ML3), but MS3 and MS6, located slightly upstream of the two weirs, were found to be loamy sand and silt loam, respectively. The concentrations of Pb, Zn, Cu, Cd and Hg were higher at the upstream sites, while As, Cr, Ni and Li were higher at the downstream sites. The heavy metals of crustal origin (As, Cr, Ni and Li) were strongly correlated with particle size, while the other heavy metals (Pb, Zn, Cu, Cd and Hg) were weakly correlated with particle size. Considering their concentrations, most of heavy metals were evaluated as having almost no toxic effects on benthic organisms, at all sites. In addition, anthropogenic contamination by the $I_{geo}$, EF and CF were found to have no impact at most sites, with only low levels of pollution at the others. Using the PLI method, the MS2 and MS3 sites, located upstream, were assessed to be affected by anthropogenic contamination. Most importantly, Zn, Cu and Hg were found to be the elements responsible for most pollution, and they were highest at the upstream sites, implying pollution by domestic sewage and urban discharge.

Abundances of refractory elements for stars with extrasolar planets : New samples

  • 박선경;강원석;이상각;이정은
    • 천문학회보
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    • 제36권2호
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    • pp.147.1-147.1
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    • 2011
  • We investigate the chemical differentiation in F, G, K type stars with and without planets to extend the work by Kang et al. (2011) to various spectral types. Since the primordial chemical composition has been preserved in the stellar atmosphere, stellar metallicity can provide the information on the primordial material, which is the potential building block of planets. Therefore, we can explore the favored conditions for planet formation through the comparison of chemical compositions between planet-host stars (PHSs) and stars without planets. In this work, we analyze 19 F, G, and K type stars. In each spectrum, we measure equivalent widths (EWs) of Fe, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni using TAME (Tools for Automatic Measurement of Equivalent width). The abundances of these species can be derived with the measured EWs and MOOG code (Sneden 1973). Like results by precedent studies, we find that planet-host stars have abundances higher than stars without planets. The typical difference in the abundances of Na, Mn, Co and Ni is $0.4{\pm}0.2dex$. In addition, as found in Kang et al. (2011), Mn is the most different element between PHSs and comparison stars.

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생체용 316LVM 스테인레스강 개발에 관한 연구 (Study on the 316LVM Stainless Steel for Surgical Implant Materials)

  • 신명철;이규환;이한구
    • 대한의용생체공학회:의공학회지
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    • 제3권2호
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    • pp.71-82
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    • 1982
  • The 316LVM stainless steel that is widely used in surgical implant has been studied. The objective of this study is to develop the domestic production of the surgical implant materials. In the work, the metalllirgical phenomena, physical and chemical properties and biocompatibility of the materials are investigated. According to the experimental observation, corrosion resistance is strongly depended on the -ferrite structure and passive film, and mechanical properties are mainly depended on the cold reduction ratio. The -ferrite structure is minimized in the 16.651 Cr and 14%Ni contents, and yield strength is 104 kg/mm$^2$ at 45% cold reduction. Biocompatibility is excellent in the mouse body test for six weeks.

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비선형성 ZnO 바리스터의 Prebreakdown 영역에서의 전도 현상 (Conduction Mechanism of Non-linearity ZnO Varistor in the Prebreakdown region)

  • 한세원;강형부
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1995년도 추계학술대회 논문집
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    • pp.74-76
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    • 1995
  • ZnO varistor with composition of ZnO(90wt%)-Bi$_2$O$_3$(3wt%)-Sb$_2$O$_3$(3.6wt%)-CO$_2$O$_3$(1.16wt%)-NiO(0.88wt%)-MnO$_2$(0.71wt%)-Cr$_2$O$_3$(0.93wt%) according to Al$_2$O$_3$addtive was fabricated by sintering methods. The effects of Al$_2$O$_3$dopant on the I-V characteristics of ZnO varistors were investigated. These changes of electric properties were found to be caused by the variation of grains and grain boundary related to Al$_2$O$_3$dopting. And the conductive mechanism of ZnO varistor in prebreakdown region were investigated with defect model.

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오스테나이트계 스테인레스강의 육성 용접부에서 고온균열 감수성에 미치는 용접입열의 영향

  • 김대영;김희진
    • Journal of Welding and Joining
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    • 제6권2호
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    • pp.40-46
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    • 1988
  • The effect of heat input on the content of residual .delta.-ferrite and the hot cracking susceptibility in the austenitic stainless steel overlaid on the carbon steel was studied in the range of heat input from 7.5 to 15.1 KJ/cm. Present study shows that residual .delta.-ferrite content in the overlay is mainly determined by the dilution of the base metal (carbon steel) which is in turn affected by heat input, i.e. the amount of dilution decreases as heat input increase. Accordingly, higher heat input results in a substantial increase in Cr equivalent but a little increase in Ni equivalent due to the less dilution of carbon from base metal. This fact can explain the result obtained in this study, i, e, the higher content of .delta.-ferrite in the weld deposit made with higher heat input. This in turn causes more resistant overlaying weld metal to hot cracking.

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Chemical abundance study of two open cluster, IC 2391 and NGC 6475 : The abundance determination

  • 박근홍;이상각;강원석;윤태석
    • 천문학회보
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    • 제36권2호
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    • pp.146.2-146.2
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    • 2011
  • In this study, we have derived the abundances of several elements ? Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Co, Ni - for the six F G K type stars in IC 2391 and the seven stars in NGC 6475. The spectra of those stars are taken from UVES POP archive data, of which resolution is 80,000. To derive the abundances of those elements, TAME (Tools for Automatic Measurement of Equivalent-widths), Kurucz stellar atmospheric model, and MOOG code are used. The stellar parameters (effective temperature, log g, metallicity, microturbulent velocity) are determined from the iron lines. The results provide the abundance differences of chemical elements between two open clusters, IC 2391 (a member of Gould Belt) and NGC 6475 (non-member of it), which would lead to better understanding about Gould Belt.

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고크롬주철의 잔류오스테나이트함량에 미치는 화학조성 및 불안정화열처리의 영향 (The Effect of Chemical Composition and Destabilization Heat Treatment on the Amount of Retained Austenite in High Chromium Cast Irons)

  • 류성곤
    • 한국재료학회지
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    • 제6권4호
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    • pp.372-378
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    • 1996
  • 고크롬주철에 있어서 기지 및 탄화물의 조직제어는 내마모성의 향상을 위해 필수적이다. 특히 기지조직내의 잔류오스테나이트함량은 최적 내마모성을 얻기위해 반드시 조절되어야 한다. 본 연구에서는 3% C-18%(or 25%)Cr-Mo-Ni-Mn 고크롬주철을 80$0^{\circ}C$, 90$0^{\circ}C$, 100$0^{\circ}C$ 및 110$0^{\circ}C$의 질소분위기 하에서 각각 20분 불안정화열처리를 행한 후 공냉시켰다. 잔류오스테나이트의 함량은 Xtjs 회절시험을 통해 측정하였으며 회절 peak는 $\alpha$200, $\alpha$220, ${\gamma}$220그리고 ${\gamma}$311을 이용하였다. 화학조성, 불안정화열처리의 온도 및 시간, 그리고 잔류오스테니이트함량강의 관계식을 도출하였다.

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화학증착법에 의한 강에의 알루미나 피복에서 구조-성질-과정에 관한 연구 (The Study of Structre-Peoperty-Process in Alumina Coating of Steel by Chemical Vapour Deposition Process)

  • 최진일
    • 한국표면공학회지
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    • 제22권3호
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    • pp.135-144
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    • 1989
  • Aluminium Oxide was deposited with a C.V.D.-technique on various substrates. The effects of various treating condition such as temperature, time, heat resistance and composition of substrates were investigated in order to understand the relationship of structure, property and process. Grain size depends upon the activity of adsorption siite and coarsened with increasing temperature and time. Deposition rate decreases in order of electrolytic iron, carbon steel STS430 and STS304, since the active site for adsorption of reactant was more decreased for Cr and Ni than Fe. Oxidation resistance of alumina coated specimens improved markedely and that of stainless steel was prominent.

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탄소강과 스테인리스강의 진공브레이징에 관한 연구 (A study on the vacuum brazing of carbon steels to a stainless steel)

  • 이창동;나석주
    • 대한기계학회논문집
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    • 제12권5호
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    • pp.1083-1091
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    • 1988
  • 본 연구에서는 위의 두번째 연구동향과 맥락을 같이하는 것으로서 스테인리스 강(SUS304)에 대한 진공브레이징 연구 및 탄소강의 진공 브레이징에 대한 연구결과들 을 토대로 하여 SUS304와 탄소강과의 진공브레이징 현상을 연구하였는데 특히 모재의 탄소함유량, 브레이징시간 및 접합부 틈새(joint clearance)등에 따라 접합부에 나타 나는 여러 금속학적 현상의 규명 및 접합강도(joint strength)에 대해 변수들이 미치 는 영향을 연구 하였다.

미얀마 북서부 보피붐 크롬철석 광화대의 산출특성 (Occurrence Characteristics of Bophi Vum Chromite Mineralized Zone in the Northwestern Myanmar)

  • 허철호;지세정;강일모;진광민
    • 자원환경지질
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    • 제47권4호
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    • pp.351-362
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    • 2014
  • 미얀마 북서부 보피붐 크롬-광화대에 대한 지질특성, 광체산상 및 개발 잠재성을 파악하기 위하여 광화대내 약 $6km^2$ 탐사지역을 설정하여 한국지질자원연구원과 미얀마 지질조사광물탐사국이 현지 공동조사를 수행하였다. 조사지역 내 크롬광체는 주로 더나이트에 수반된 크롬철석암으로 해발 200-400 m 구간에 걸쳐 지표상에 분포하고 있는 것을 확인하였으며 지표지질 및 광상조사를 수행하여 1:1,000 축척의 정밀 지질도 및 광상분포도를 작성하였다. 지질 및 광상 조사와 병행하여 토양 지화학 탐사를 수행하였으며, 50 m 간격으로 총 114개 지점에 대한 피팅탐사를 실시하여 토양과 노두시료를 채취 분석 하였고, ICP-AES를 이용하여 Cr, Ni, Fe, Mn에 대한 지화학이상대도를 작성하였다.