• 제목/요약/키워드: Al-Mg-Si

검색결과 904건 처리시간 0.024초

여수 봉산동 출토의 사철 쇠똥에 대하여 (Metallography of Iron Slag Excavated from Bongsan-dong, Yeosu City in the Period of the 16th to 19th Century)

  • 최주;김수철;도정만
    • 보존과학회지
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    • 제3권1호
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    • pp.13-18
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    • 1994
  • Chemical analysis and metallographic observations of the iron slag were carried out in an attempt to estimate the old iron-making process. The slag containing $9.3\%\;TiO_2$ without Cu indicates that the ore used for smelting was sand iron, not rock ore. The phases identified in the slag were $ulv\ddot{o}spinel$, magnetite, $w\ddot{u}stite$, fayalite etc. This also supports the fact that the smelted ore was iron sand. The total amount of Fe and slag-making components$(=SiO_2+Al_2O_3+MgO+CaO)$ were $40.7\%\;and\;36.1\%$, respectively. These values were average ones found in the old slags formed in the ancient iron-making process. Assuming that $TiO_2$ in the ore combines with FeO, resulting in the formation of $ulv\ddot{o}spinel$, the estimated temperature of smelting was found to be about $1200^{\circ}C$.

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금형 충전 해석을 이용한 연료전지 분리판 진공 다이캐스팅 금형 설계 방안 및 실험 검증 (Vacuum Die Casting Mold Design of Fuel Cell Bipolar Plate using Die Filling Simulation and Experimental Verification)

  • 진철규;장창현;강충길
    • 한국주조공학회지
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    • 제32권2호
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    • pp.65-74
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    • 2012
  • In this paper, we present the results of our studies on optimal die design towards development of a vacuum die casting process to fabricate fuel cell bipolar plate with micro-channel array. Cavity and overflow shape is designed by computational filling analysis of MAGMA soft. Optimal die design consists of seven overflows at the end of cavity and three overflows at each side wall of cavity. The molten metal that passed the gate and reached the side wall flowed into the side overflow, no turbulent flow occurred, and the filling behavior and velocity distribution were uniform. In addition, partially solidified molten metal passing through the channel was perfectly eliminated by overflow without back-flow. When vacuum pressure, injection speed of low and high region was 300 mbar, 0.3 m/s and 2.5 m/s respectively with Silafont 36 die casting alloy, sound sample without casting defects was obtained. The experimental results are nearly consistent with simulation results.

온천수가 반죽의 발효와 품질에 미치는 영향

  • 이예경;김순동;이명예;김미영
    • 한국식품저장유통학회:학술대회논문집
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    • 한국식품저장유통학회 2003년도 춘계총회 및 제22차 학술발표회
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    • pp.121.1-121
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    • 2003
  • 증류수, 수도수, 온천수(경산 사이판 온천) 희석액 (55배 희석; I, 4배 희석; II, 2배희석; III을 사용한 반죽의 발효와 빵의 품질에 미치는 영향을 조사하였다. 경산사이판 온천수는 총고형물이 8,765 ppm 이였으며 주요 무기질로는 Na가 2296 ppm, Ca가 287 ppm, Mg와 K가 각각 65 및 8 ppm을 함유하였다. Fe, Cu, Co, F. Zn Al, S, Mo, Se 및 Si 등이 0.002~5.2 ppm을 함유하였다. 온천수를 사용한 반죽의 pH는 6.95~7.68로 증류수의 6.40보다 높았다. 반죽부피는 온천수의 농도가 높아짐에 따라 감소하였다. pH를 5.5로 조정한 온천수를 사용한 반죽의 부피는 대조구 보다 오히려 높았다. 온천수를 사용한 빵의 경도 (hardness)와 신장성(strength)는 대조구 보다 높았으나 pH를 조정한 온천수의 경우는 낮았다. 점착성은 경도 및 신장성과는 역으로 희석 온천수에서 낮았다. pH 조정 없이 구운 빵의 부드러운 정도는 4배로 희석한 온천수가 증류수 및 55배, 2배 희석 온천수보다 높았다. 쫄깃한 맛도 온천수가 대조구에 비하여 높았으며 종합적인 기호도는 4배 희석 온천수가 가장 좋았다.

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자동차 휠용 6061 Al합금의 단조 및 T6 열처리 전후의 미세조직과 기계적 특성 평가 (Evaluation of Mechanical Property and Microstructure of Forged and T6-treated 6061 Aluminum Alloy Wheel)

  • 이지혜;정헌수;염종택;김정한;박노광;이용태;이동근
    • 소성∙가공
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    • 제16권5호통권95호
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    • pp.354-359
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    • 2007
  • Effects of forging and mechanical properties of 6061 aluminum alloy wheel for automobiles were investigated in the present study. Microstructural and tensile characteristics of automobile wheel after hot forging process using dynamic screw press were analyzed to evaluate effect of metal flow on mechanical properties. The results showed advanced mechanical properties of 6061 alloy wheel because of $Mg_2Si$ precipitation by T6, elongated grain by forging, and work hardening by dense metal flow, etc. Hot compression tests were conducted in order to characterize high temperature compression deformation behaviors and microstructural variation in the range of $300{\sim}450^{\circ}C$, in the strain rate range of $10^{-3}{\sim}10^1\;sec^{-1}$. As strain rate increased, maximum compression stress increased but it was shown the reverse linear relation between temperature and maximum stress irrelevant to strain rate variation. On the other hand, temperature and yield stress didn't have any linear relation and its relation showed big deviation by a function of strain rate and test temperature.

부산지역 강하먼지와 불용성 성분의 침적량에 관한 연구 (A Study on Bulk Deposition Flux of Dustfall and Insoluble Components in Pusan, Korea)

  • 김유근;박종길;문덕환;황용식
    • 한국환경과학회지
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    • 제10권3호
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    • pp.209-216
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    • 2001
  • Dustfall particles were collected by the modified American dust jar (wide inlet bottle type) at 6 sampling sites in Pusan area from March, 1999 to February, 2000. Thirteen chemical species (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Si, and Zn) were analyzed by AAS and ICP. The purposes of this study were to estimate qualitatively various bulk deposition flux of dustfall and insoluble components by applying regional and seasonal distribution. Dustfall amount of regional variations were found in order of coastal zone, industrial zone, commercial zone, agricultural zone and residential zone, and seasonal total dustfall had higher concentrations during spring for 6.741 ton/${km}^2$/season, lower concentrations during summer for 1.989 ton/${km}^2$/season, and annual total concentration was 17.742 ton/${km}^2$/year. The regional distributions of enrichment factor show well-defined anthropogenic metals (Cd, Cu, Pb, and Zn) at industrial and agricultural zone, and contribution rate of soil particles were found in order of summer, fall, winter and spring. Factor loading effects of chemical composition of dustfall were found in order of road traffic emission source and combustion processed source, industrial activity source, soil source and marine source.

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The Effects of Individual Element Changed Mixture on the Standard Stellar Models

  • Beom, Minje;Lee, Young-Wook;Ferguson, Jason W.;Kim, Yong-Cheol
    • 천문학회보
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    • 제39권2호
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    • pp.84.1-84.1
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    • 2014
  • This research is to study the effects of individual element(C, N, O, Na, Mg, Al, Si, and Fe) on the standard stellar models. Our work is different from previous works in two aspects. Firstly, we have chosen to maintain helium abundance and other metal elements as target elements were changed. This is to see the effects more clearly, without further complication. Secondly, the amount of enhancement or reduction in each element has been based on the recent observation of stars in globular clusters. For comparison study with observation of the globular clusters, the mass and metallicity grids of the standard stellar models have been constructed in range $0.7{\sim}1.0M{\odot}$ and 0.0002~0.007, respectively. The opacity as a function of depth in stellar models at equal evolutionary point, as well as the evolutionary tracks, have been analyzed. The quantified shifts of the evolutionary tracks for the stellar models which have changed abundance of individual element and the astronomical meaning with physical reasons which produce the results, are going to be presented in this talk.

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박막트랜지스터 게이트 절연막 응용을 위한 불화막 특성연구 (The Study of Fluoride Film Properties for Thin Film Transistor Gate Insulator Application)

  • 김도영;최석원;안병재;이준신
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제48권12호
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    • pp.755-760
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    • 1999
  • Various fluoride films were investigated for a gate insulator of thin film transistor application. Conventional oxide containing materials like $SiO_2\;Ta_2O_5\; and \; Al_2O_3$ exhibited high interface states which lead to an increased threshold voltage and poor stability of TFT. In this paper, we investigated gate insulators using a binary matrix system of fluoride such as $CaF_2,\; SrF_2\; MgF_2,\; and\; BaF_2$. These materials exhibited an improvement in lattice mismatch, interface state and electrical stability. MIM and MIS devices were employed for an electrical characterization and structural property examination. Among the various fluoride materials, $CaF_2$ film showed an excellent lattice mismatch of 5%, breakdown electric field higher than 1.2MV/cm and leakage current density of $10^{-7}A/cm^2$. MIS diode having $Ca_2$ film as an insulation layer exhibited the interface states as low as $1.58\times10^{11}cm^{-2}eV^{-1}$. This paper probes a possibility of new gate insulator materials for TFT applications.

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알루미나를 첨가한 코디어라이트계 결정화 유리의 소결거동 및 결정화 특성 (The Sintering Mechanism and Crystallization Characteristics of Alumina-filled Cordierite-type Glass-ceramics)

  • 박정현;노재호;성재석;구기덕
    • 한국세라믹학회지
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    • 제35권7호
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    • pp.706-714
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    • 1998
  • The MgO-{{{{ { {Al }_{2 }O }_{3 } }}-{{{{ { {SiO }_{2 } }_{ } }}system containing alumina powder was fabricated sintered at various temperature and analyzed in order to study the sintering mechanism and crystallization characteristics. The specimen composed of glass powder with average particle size of 8.27 $\mu\textrm{m}$ and 0-40 vol% alumina powder were sint-ered for 3 hrs at the temperature between 850$^{\circ}C$ and 1350$^{\circ}C$ The sintering mechanism consists of the redis-tribution of particles occuring at 750$^{\circ}C$ and the viscous flow at 850∼950$^{\circ}C$. The degree of crystallization and sintering temperatue were dependent upon the ratio of glass/alumina. The second phase from the reaction between glass and alumina was not observed which was confirmed by XRD and properties analysis. The density dielectric constant and specific resistivity of specimen were 2.30∼3.26g/cm2 5.8∼7.38 at 1 GHz density dielectric constant and specific resistivity of specimen were 2.30∼3.26g/cm3 5.8∼7.38 at 1GHz and 1.23∼4.70${\times}$107 $\Omega$$.$m respectively.

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인듐량에 따른 InxGaN1-x 박막의 에너지밴드갭 변화 (Energy-band-gap Variation of InxGaN1-x Thin Films with Indium Composition)

  • 박기철;마대영
    • 한국전기전자재료학회논문지
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    • 제22권8호
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    • pp.677-681
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    • 2009
  • $In_xGa_{1-x}N$ alloys with 20-nm-thickness were deposited onto Mg:GaN/AlN/SiC substrates by MOCVD at $800\;^{\circ}C$. TMGa, TMIn and $NH_3$ were used as the precursor of gallium, indium and nitrogen, respectively. The mole ratio of indium in $In_xGa_{1-x}N$ films varied between 0 and 0.2. The energy-band-gaps of the films were obtained from the photoluminescence and cathodoluminescence peaks. The mole ratios of $In_xGa_{1-x}N$ films were calculated by applying Vegard's law to XRD results. The energy-band-gap versus indium composition plot for $In_xGa_{1-x}N$ alloys were well fit with a bowing parameter of 2.27.

Effects of annealing atmosphere on optical and electrical properties of Zn doped ITO films synthesized by combinatorial sputter system

  • 김인기;김성대;허기석;김진혁;김태원
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.153-153
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    • 2008
  • 최근 투명전극물질이 LCD, 박막태양전지, smart window, 유기발광소자 등에 폭넓게 이용됨에 따라 그 수요가 급격이 늘어나고 있다. 이러한 투명전극 물질로는 Al : ZnO, Ga : ZnO, $MgIn_2O_4$, $AgSbO_3$, $InGaZnO_4$, ITO, Zn:ITO 등이 있으며 이중 ITO 계 산화물은 우수한 전기적 특성을 바탕으로 이미 상용화 되어있는 상태이다. 그러나 ITO 계 산화물은 indium 의 희소성과 높은 가격 때문에 폭 넓은 분야의 상용화가 어려운 실정이며, 수소 플라즈마 분위기에 화학적으로 불안정한 특성은 Si 박막태양전지 응용에 큰 문제가 되고 있다. 이에 본 연구는 박막태양전지용 ITO 계 투명전극의 indium양을 줄이면서 화학적으로 안정하고, 전기적 특성이 향상된 박막을 제조하기 위해 combinatorial sputter를 이용하여 Zn의 도핑량을 연속적으로 변화시킨 ITO 박막을 제조하였다. 또한 광학적 전기적 특성의 향상을 위해 vacuum, $H_2$, $O_2$ 분위기에서 열처리 후 각 박막의 특성 변화를 관찰하였다.

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