• 제목/요약/키워드: Pure Ti

검색결과 598건 처리시간 0.031초

H2S를 포함하는 연료를 사용하기 위한 고체산화물 연료전지용 Sr0.92Y0.08Ti1-xVxO3-δ 연료극 특성 (Characteristics of Sr0.92Y0.08Ti1-xVxO3-δ (x = 0.01, 0.04, 0.07, 0.12) Anode for Using H2S Containing Fuel in Solid Oxide Fuel Cells)

  • 장근영;김준호;모수인;박광선;윤정우
    • Korean Chemical Engineering Research
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    • 제59권4호
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    • pp.557-564
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    • 2021
  • 페로브스카이트 구조를 갖는 Sr0.92Y0.08Ti1-xVxO3-δ (SYTV)는 고체산화물 연료 전지(Solid oxide fuel cell, SOFC)에서 H2S를 포함하는 연료를 사용하기 위한 대체 연료극으로 연구되었다. Sr0.92Y0.08TiO3-δ (SYT)의 전기화학적 성능을 향상시키기 위해 페로브스카이트의 B-사이트에 위치한 티타늄을 바나듐으로 치환하였다. 페치니법을 통해 합성된 SYTV는 작동 온도 조건에서 추가적인 부산물의 형성 없이 YSZ(yttria-stabilized zirconia) 전해질과 화학적으로 안정했다. 바나듐의 치환량이 증가함에 따라 산소 공공 결함(Oxygen vacancy)이 증가하였으며, 생성된 산소 공공 결함으로 인해 연료극의 이온 전도도가 증가했다. 전지 성능은 850 ℃ 순수한 H2 연료 조건에서 바나듐 치환 정도에 따라 1 mol.%의 바나듐이 치환된 경우 19.30 mW/cm2 이고 7 mol.%의 바나듐이 치환된 경우 34.87 mW/cm2이다. 1000 ppm의 H2S를 포함하는 H2 연료조건에서 cell의 최대 전력밀도는 1 mol.%의 경우 22.34 mW/cm2이고 7 mol.%의 경우 73.11 mW/cm2로 증가하였다.

Aerosol Deposition and Its Potential Use for Bioactive Ceramic Coatings

  • Hahn, Byung-Dong;Park, Dong-Soo;Lee, Jeong-Min;Choi, Jong-Jin;Ryu, Jung-Ho;Yoon, Woon-Ha;Lee, Byoung-Kuk;Choi, Joon-Hwan;Kim, Hyoun-Ee
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2009년도 추계학술발표대회
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    • pp.41.1-41.1
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    • 2009
  • Aerosol Deposition (AD) is anovel way to fabricate bioactive ceramic coatings in biomedical implants and prostheses applications. In the present work, silicon-substituted hydroxyapatite (HA) coatings on commercially pure titanium were prepared by aerosol deposition using Si-HA powders. The incorporation of silicon in the HA lattice is known to improve the bioactivity of the HA, makingsilicon-substitute HA an attractive alternative to pure HA in biomedical applications. Si-HA powders with the chemical formula $Ca_{10}(PO_4)_6-x(SiO_4)x(OH)_2-x$, having silicon contents up to x=0.5 (1.4 wt%), were synthesized by solid-state reaction of $Ca_2P_2O_7$, $CaCO_3$, and $SiO_2$. The Si-HA powders were characterized by X-ray diffraction (XRD), X-ray fluorescence spectrometry (XRF), and Fourier transform infrared spectroscopy(FT-IR). The corresponding coatings were also analyzed by XRD, scanning electron microscopy (SEM), and electron probe microanalyzer (EPMA). The results revealed that a single-phase Si-HA was obtained without any secondary phases such as $\alpha$- or $\beta$-tricalcium phosphate (TCP) for both the powders and the coatings.The Si-HA coating was about $5\;{\mu}m$ thick, had a densemicrostructure with no cracks or pores. In addition, the proliferation and alkaline phosphatase (ALP) activity of MC3T3-E1 preosteoblast cells grown on the Si-HA coatings were significantly higher than those on the bare Ti and pure HA coating. These results revealed the stimulatory effects induced by siliconsubstitution on the cellular response to the HA coating.

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충주지역 호상 및 괴상 철광상의 성인에 관한 연구(I) : 지질 및 광석의 산출특성 (Banded and Massive Iron Mineralization in Chungju Mine(I): Geology and Ore Petrography of Iron Ore Deposits)

  • 김근수;박맹언;엔조지 마모루
    • 자원환경지질
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    • 제27권6호
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    • pp.523-535
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    • 1994
  • 충주 광산은 한반도의 대표적인 층상 규제형 (strata-bound type) 철광상의 하나이다. 광산 부근의 지질은 규암 및 편암류로 구성되는 변성 퇴적암 (계명산층)과 후기의 관입 화성암으로 이루어져 있다. 철광층은 주로 변성암의 편리와 조화적 관계를 가지며 층상 또는 렌즈상으로 산출되고 부분적으로 불규칙한 괴상으로 발달되기도 한다. 광상은 산출상태, 구조 및 조직, 구성 광물의 공생특성 등에 의해 호상광석과 괴상광석으로 구분된다. 호상광석 (banded ore)은 적철석, 적철석+자철석, 자철석 및 석영이 우세한 분대 (meso- bands)의 반복에 의한 대상구조가 특정적이다. 괴상광석 (massive ore)은 화강암질 암석의 접촉부를 따라 불규칙한 형태로 산출되며, 대부분이 자철석으로 구성된다. 철산화광물 및 규산염 광물의 입자 크기는 호상광석에서 보다 괴상광석에서 더 조립질을 나타낸다. 호상 및 괴상광석을 구성하는 자철석의 조성은 거의 순수한 $Fe_3O_4$로 구성되지만, Mn의 함량에서 차이가 있음을 알 수 있다 (호상광석; 0.14~0.27 MnO wt.%, 괴상광석; 0.10~0.15 MnO wt.%). 적철석은 Ti 성분이 호상 (0.87~1.27 $TiO_2$ wt.%) 및 괴상 (3.51~6.96 $TiO_2$ wt.%) 광석에서 뚜렷한 차이를 보인다. 광석에 수반되는 흑운모의 화학조성은 호상광석이 괴상광석에서보다 FeO, $TiO_2$$Al_2O_3$ 값은 낮고, MgO와 $SiO_2$는 높다. 충주 철광상은 퇴적작용 내지 변성작용의 특성을 나타내는 대상 (층상)구조와 괴상조직 및 교대조직등의 다양한 변화과정을 반영하고 있으며, 산출상태, 광석광물의 조성 및 조직적 특성은 괴상광석 형성이 호상 광석보다 더 환원적인 환경 또는 고온의 온도 조건에서 야기되었음을 지시한다. 철광상은 초기 철의 퇴적(공급)작용과 후기의 변성작용에 의해 2차 부화작용에 의해 복합적으로 형성된 것으로 추정된다. 호상광석은 광역변성작용에 의해, 괴상광석은 화강암 관업에 의한 영향으로 사료된다.

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경복궁 근정전 단청안료의 성분분석 (The composition analysis of Danchung pigments at Geunjeongjeon Hall in Gyeongbokgung Palace)

  • 조남철;문환석;홍종욱;황진주
    • 보존과학연구
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    • 통권22호
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    • pp.93-114
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    • 2001
  • The composition analysis of Danchung pigments at Geunjeongjeon Hall in Gyeongbokgung Palace were carried out by FXRF and MXRD. The analytical result of the inside pigments at Geunjeongjeon showed that these painted in use the mineral pigments. Gold pigment was pure gold(Au).The main composition identified in green pigments were chalcanthite($CuSO_4$.$5H_2O$) and celadonite($K(Mg, Fe, Al)_2$.$(Si, Al)_4O_10(OH)_2$ ). Red pigments werecinnnabar(HgS).The analytical result of the outside pigments at Geunjeongjeon revealed that these applied to the artificial synthetic pigment. Yellow pigment was chromeyellow($PbCrO_4$). The main composition identified in red pigments were red lead($Pb_3O_4$)and hematite($Fe_2O_3$). Green pigments were emeral green($C_2H_3A_s3Cu_2O_8$) and chromegreen($Cr_2O_3$). Blue pigment was lazurite($Na_6Ca2Al_6Si_6O_24(SO_4)_2$), titanium dioxide($TiO_2$) of white pigment.

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Carbon Nanotubes Doped with Nitrogen, Pyridine-like Nitrogen Defects, and Transition Metal Atoms

  • Mananghaya, Michael R.
    • 대한화학회지
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    • 제56권1호
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    • pp.34-46
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    • 2012
  • Dopants and defects can be introduced as well as the intercalation of metals into single wall carbon nanotubes (SWCNTs) to modify their electronic and magnetic properties, thus significantly widening their application areas. Through spinpolarized density functional theory (DFT) calculations, we have systemically studied the following: (i) (10,0) and (5,5) SWCNT doped with nitrogen ($CN_xNT$), (ii) (10,0) and (5,5) SWCNT with pyridine-like defects (3NV-$CN_xNT$), and (iii) chemical functionalization of (10,0) and (5,5) 3NV-$CN_xNT$ with 12 different transition metals (TMs) (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Pd, and Pt). Attention was done in searching for the most stable configurations, deformation, calculating the formation energies, and exploring the effects of the doping concentration of nitrogen and pyridine-like nitrogenated defects on the electronic properties of the nanotubes. Also, calculating the corresponding binding energies and effects of chemical functionalization of TMs on the electronic and magnetic properties of the nanotubes has been made. We found out that the electronic properties of SWCNT can be effectively modified in various ways, which are strongly dependent not only on the concentration of the adsorbed nitrogen but also to the configuration of the adsorbed nitrogen impurities, the pyridine-like nitrogenated defects, and the TMs absorbed; due to the strong interaction between the d orbitals of TMs and the p orbitals of N atoms, the binding strengths of TMs with the two 3NV-$CN_xNT$ are significantly enhanced when compared to the pure SWCNTs.

GTAW 펄스 용접 조건에 따른 타이타늄 정밀관의 용입, 변색 및 굽힘특성 (Effects of GTAW Pulse Condition on Penetration, Discoloration and Bending Property for Titanium Tube)

  • 민성환;안성용;박지태;박영도;강남현
    • Journal of Welding and Joining
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    • 제32권6호
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    • pp.47-55
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    • 2014
  • The purpose of the study is to produce a mechanically improved weld and minimum variation of color through comparing unpulsed and pulsed GTAW (Gas Tungsten Arc Welding) for pure titanium (CP grade7) tube. Pulsed GTAW using 60 A peak current and 20 A background current (1:9) achieved the wider window of welding conditions having part and full penetration without burn-through than the case of unpulsed GTAW. Moreover, the pulsed welding reduced a discoloration on the back bead of the weld and the size of microstructures (basket weave and serrated ${\alpha}$). That is because the pulsed welding has it's a low heat input and severe weld flow induced from electric current variation. Furthermore, the pulsed welding improved the bending property of the welded Ti tube. The enhanced bending property for the pulsed GTAW was due to the insignificant discoloration on the weld surface with maintaining the metal polish.

PNN 치환량에 따른 저손실 저온소결 PMN-PNN-PZT 세라믹스의 압전 및 유전특성 (Piezoelectric and Dielectric Characteristics of Low Loss Low Temperature Sintering PMN-PNN-PZT Ceramics with the amount of PNN Substitution)

  • 류주현;김국진;정영호;이수호
    • 한국전기전자재료학회논문지
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    • 제20권9호
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    • pp.766-770
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    • 2007
  • In this study, in order to develop low temperature sintering ceramics for multilayer piezoelectric actuator, $0.07Pb(Mn_{1/3}Nb_{2/3})O_3-xPb(Ni_{1/3}Nb_{2/3})O_3-(0.93-x)Pb(Zr,Ti)O_3$ ceramics system were fabricated using $Li_2CO_3-Bi_2O_3-CuO$ sintering aids and the specimens were sintered at $930^{\circ}C$. Thereafter, their piezoelectric and dielectric characteristics were investigated according to the amount of PNN substitution. At 9 mol% PNN substitution, density, electromechanical coupling factor ($k_p$), dielectric constant, mechanical quality factor ($Q_m$) and piezoelectric constant ($d_{33}$) showed the optimum value of $7.86g/cm^3$, 0.60, 1640, 1323 and 387 pC/N, respectively. It is considered that these values are suitable for piezoelectric divece application such ad multilayer piezoelectric actuator and ultrasonic vibrator with pure Ag internal electrode.

저압 임팩터를 이용한 대기 에어로졸 입자의 입경분포 측정과 화학조성 자료의 해석 (Characterization of Chemical Composition and Size Distribution of Atmospheric Aerosols by Low-Pressure Impactor)

  • 박정호;최금찬
    • 한국대기환경학회지
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    • 제13권6호
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    • pp.475-486
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    • 1997
  • The characteristics of atmospheric aerosols were investigated as a function of particle size and water solubility. The atmospheric aerosols were sampled with classifying into 12 size ranges by the use of Andersen low-pressure impactor. Collected aerosol particles were extracted by ultrapure water and filtered to be separated into water-soluble and insoluble components. The concentrations 12 elements in both components were determined by PIXE analysis. And the concentrations of 8 ions in the soluble component were analyzed by ion chromatography. In general, the mass size distribution of particulate matter was represented as a bimodal distribution. The mass size distributions of S$(SO_4^{2-}), K(K^+), Zn and NH_4^+$ skewed to the smaller size range and those of Si, Ca$(Ca^{2+}), Fe, Na^+ and Mg^{2+}$ skewed to the larger size range. They had roughly one peak in the fine and coarse particle region,respectively. On the other hand, the mass size distribution of Ti, Mn, Ni, Cu, $Cl^- and NO_3^-$ were represented as the bimodal distribution. Fe and Si in the aerosol particles extracted into pure water are existing in high insoluble state. Conversely, almost the whole of S is dissolved in water.

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산화티타늄피막의 광 전기분해 특성에 대한 연구 (A Study of Photoelectrolysis of Water by Use of Titanium Oxide Films)

  • 박성용;조원일;조병원;이응조;윤경석
    • 한국수소및신에너지학회논문집
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    • 제2권1호
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    • pp.47-56
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    • 1990
  • Pure titanium rods were oxidized by anodic oxidation, furnace oxidation and flame oxidation and used as a electrode in the photodecomposition of water. The maximum photoelectrochemical conversion efficiency(${\eta}$) was found for flame oxidized electrode ($1200^{\circ}C$ for 2 min in air), 0.8 %. Anodically oxidized electrodes have minimum photoelectrochemical conversion efficiencies, 0.3 %. Furnace oxidized electrode ($800^{\circ}C$ for 10min in air) has 0.5% phtoelectrochemical efficiency and shows a band-gap energy of about 2.9eV. The efficiency shows a parallelism with the presence of the metallic interstitial compound $TiO_{O+X}$(X < 0.33) at the metal-semiconductor interface, the thickness of the sub oxide layer and that of the external rutile scale.

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Epitaxial Growth of $BiFeO_3-Ba(Cu_{1/3}Nb_{2/3})O_3$ Thin Films Deposited by Pulsed Laser Deposition

  • 백창우;이종필;성길동;정종훈;류정호;윤운하;박동수;정대용
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.30.1-30.1
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    • 2011
  • Multiferroic thin films with composition $0.9BiFeO_3-0.1Ba(Cu_{1/3}Nb_{2/3})O_3$ were epitaxially grown by pulsed laser deposition on $SrRuO_3(001)/SrTiO_3$ (000) substrate $0.9BiFeO_3-0.1Ba(Cu_{1/3}Nb_{2/3})O_3$, which is assumed to be morphotropic phase boundary (MPB), that showed superior dielectric, ferroelectric and magnetic properties in our study on polycrystalline films. The structures of epitaxially grown films were characterized by means of XRD. From P-E measurements, samples exhibited typical ferroelectric hysteresis loops and large remnant polarization, whose value is much larger than those of pure BFO film. The enhancement of dielectric, ferroelectric, magnetic properties was attributed to the structural distortion induced by the BCN addition and the high physical stress effect.

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