• 제목/요약/키워드: barium-poor

검색결과 13건 처리시간 0.026초

Catalytic Effects of Barium Carbonate on the Anodic Performance of Solid Oxide Fuel Cells

  • Yoon, Sung-Eun;Ahn, Jae-Yeong;Park, Jong-Sung
    • 한국세라믹학회지
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    • 제52권5호
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    • pp.350-355
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    • 2015
  • To develop ceramic composite anodes of solid oxide fuel cells without metal catalysts, a small amount of barium carbonate was added to an $(La_{0.8}Sr_{0.2})(Cr_{0.5}Mn_{0.5})O_3(LSCM)$ - YSZ ceramic composite anode and its catalytic effects on the electrode performance were investigated. A barium precursor solution with citric acid was used to synthesize the barium carbonate during ignition, while a barium precursor solution without citric acid was used to create hydrated barium hydroxide. The addition of barium carbonate to the ceramic composite anode caused stable fuel cell performance at 1073 K; this performance was higher than that of a fuel cell with $CeO_2$ catalyst; however, the addition of hydrated barium hydroxide to the ceramic composite anode caused poor stability of the fuel cell performance.

DCA-MOD 방법으로 제조하는 YBCO 박막의 임계전류밀도에 미치는 전구체 조성의 효과 (Effects of Precursor Composition on the $J_c$ of YBCO thin Films Prepared by DCA-MOD Method)

  • 김병주;김혜진;이종범;이희균;홍계원
    • Progress in Superconductivity
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    • 제9권1호
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    • pp.91-95
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    • 2007
  • [ $YBa_2Cu_3O_{7-{\delta}}$ ] films have been prepared on $LaAlO_3$ (100) single-crystal substrates by the metal organic deposition using dichloroacetate precursors (DCA-MOD). DCA precursor solutions with different composition such as; Yttrium-excess(15 at%), barium-poor(25 at%), and a stoichiometric(Y:Ba:Cu=1:2:3) were prepared in order to investigate the effects of precursor composition on the properties of YBCO films prepared by DCA-MOD method. Coated films were calcined at low temperature up to $500^{\circ}C$ in flowing humid oxygen atmosphere. Conversion heat treatment was performed $800^{\circ}C$ for 2 h in flowing Ar gas containing 1000 ppm oxygen with a humidity of 9.45%. For the film prepared using excess yttrium composition, high critical current density ($J_c$) of $>2MA/cm^2$ was obtained whereas, for the films prepared using barium-poor composition, $J_c$ was lower than $1MA/cm^2$.

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바륨 현탁액과 메틸셀룰로스(Methylcellulose)를 사용한 변형 상부위장관조영술 :전통적 바륨조영술과의 비교 (Modified Upper Gastrointestinal Study Using Methylcellulose After Administration of Barium Suspension : Comparison with Conventional Series)

  • 이기창;최민철;서민호;정주현;윤정희
    • 한국임상수의학회지
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    • 제17권2호
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    • pp.411-415
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    • 2000
  • For comparison with conventional barium-gastrointestinal study, modified method using barium and methylcellulose was performed in 16 normal dogs (4-8 kg) divided into two groups. The group 1 received 8ml/kg of 40% w/v barium suspension only, and group 2 had taken 15 ml/kg of 0.6% w/v methylcellulose after administration 4 ml/kg of 40% w/v barium suspension by feeding tube. The barium suspension was prepared mixing full strength-barium suspension with water and methylcellulose solution was produced by blending methylcellulose sterilized water Sequential radiographs, lateral and ventrodorsal projections were obtained at 5 minute, 20 minute,40 minute. 60 minute and every 30 minutes thereafter, until the contrast is seen in the large intestine Inage qual- ity was rated by three veterinary radiologists as " poor" " fair ". "good", or "excellent" We analyzed the relationship between image quality,, transit time. Between two techniques, the modified method with 4ml of 40% w/v barium suspension and 15 ml of 0.6% w/v methylcellulose showed much better image quality ["excellent" result in 7 of the 8 subjects (88%)] and shorter transit time (107 minutes) toe the cecum. In addition, the best image quality was obtained at 20 and 40 minutes after admin-istration of contrast agent. It call be concluded the modified gastrointestinal study using methylcel-lulose after administration of barium suspension was a simple technique and easily improved the image quality and diagnostic accuracy of gstrointestinal disorders in small animal.racy of gstrointestinal disorders in small animal.

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동시 증착 스퍼터링 공정에 의해 증착된 Pd-barium zirconate membrane의 구조분석 (Structural properties of Pd-barium zirconate dense membrane synthesized by dual sputtering method)

  • 변명섭;강은태;조우석;김진호;황광택
    • 한국결정성장학회지
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    • 제22권1호
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    • pp.19-24
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    • 2012
  • Barium zirconate는 화학적 안정성이 우수하고 고온에서의 프로톤 전도성이 뛰어나지만, 프로톤 전도도에 비해 전자전도도가 현저히 떨어진다. 따라서 본 연구에서는 높은 수소 분리 특성을 위해 다공성 지지체 상에 Pd-Barium zirconate를 얇고 치밀한 박막으로 제조하고자 하였고, dual sputtering법을 이용하여 성공적으로 증착하였다. X-선 회절 분석을 통해 증착된 $BaZr_{0.85}Y_{0.15}O_{3-{\delta}}$ 박막은 300 이상에서부터 $BaZrO_3$(Pm-3m) 결정상으로 결정화됨을 확인할 수 있었으며 표면과 단면에 대한 구조적 형상은 SEM과 TEM을 통해 관찰하였다. 관찰 결과 증착된 분리막은 치밀하였고 부채꼴의 주상으로 결정이 성장함을 확인할 수 있었다.

Solvothermal Synthesis and Characterization of Nano-sized Barium Titanate Powder

  • Choi, Kyoon;Kwon, Soon-Gyu;Kim, Byung-Ik
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.124-125
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    • 2006
  • Multilayer ceramic capacitor (MLCC) miniaturization has increased the demand for superfine $BaTiO_3$ powder due to its thin dielectric layer. Hydrothermally synthesized $BaTiO_3$ powder a pseudo-cubic phase resulting in poor dielectric properties due to size effect and hydroxyl ion inclusion in the $BaTiO_3$ lattice. We attempted a superfine (lower than 100 nm) highly tetragonal $BaTiO_3$ powder via a solvothermal method without precipitating agent. The lattice parameters and the relative amounts of tetragonal and cubic phases were determined using Rietveld refinement.

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성견에서 관찰된 심막-복막 허니아 증례 (Peritoneopericardial diaphragmatic hernia in adult dog)

  • 정재호;조경오;박인철;조호성;김현진;박남용
    • 한국수의병리학회지
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    • 제7권1호
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    • pp.59-62
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    • 2003
  • A two-year-old pointer dog showed a liver failure for long duration. By radiographic examination, barium or gas filled intestine was detected in the pericardium. Although liver function was bad, surgery was tried to repair hernia due to the poor prognosis. Intestine, omentum, and liver with gall bladder were dislocated in the pericadial sac by peritoneopericardial diaphragmatic hernia (PPDH). Intestine was easily removed from pericardial sac but omentum and liver were not because of strong adhesion to the pericardial sac. Postmortem examination was performed because the patient was died after surgery. Grossly, herniated liver whose right medial lobe was strongly adhered to the pericardial sac was severely congested with fibrin adhesion on the surface. Hypoplastic abnormally up-located heart had a fissure in the outside of lower right venticulum bordered apex and depressed large vessels including vena cava and aortic arch into the base of heart. It was suggested that formation of a fissure and depression of vessels might be due to the pressure of herniated organs. In the veterinary literature as far as we knew, PPDH associated with liver failure due to adhesion of liver to the pericardial sac has not been reported.

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소아의 결장에서 발생한 원발성 선암종 1예 (A Case of Mucinous Adenocarcinoma of the Sigmoid Colon in a Child)

  • 정재열;서유경;김애숙;이선주;조성민;이동석;김두권;최성민;김동훈
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • 제10권1호
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    • pp.81-85
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    • 2007
  • 소아와 청소년기에 발생하는 대장의 악성 종양은 매우 드물고 예후가 불량하다. 저자들은 내원 3개월 전부터의 식욕 부진, 체중 증가 지연과 내원 6일 전부터의 설사, 복통, 복부 종괴 촉지를 주소로 내원한 12세 남아에서 복부 초음파 촬영, 복부 전산화 단층 촬영, 바륨대장 조영술, 대장 내시경 검사 및 조직 검사 소견으로 진단된 S상 결장에 발생한 점액 선암종 1예를 경험하였기에 문헌 고찰과 함께 보고하는 바이다.

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북한 압동 니오븀-탄탈륨(Nb-Ta) 광산의 지질 및 광상 (Geology and Ore Deposit of the Apdong Nb-Ta Mine, North Korea)

  • 이재호;김유동
    • 자원환경지질
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    • 제36권6호
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    • pp.407-413
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    • 2003
  • 알칼리 교대암내에 배태되는 압동 Nb-Ta 광상의 지질은 상부원생대의 퇴적암류와 이를 관입분포하는 고생대 후기에서 중생대 초기의 평강암군에 속하는 호암산 관입암체(알칼리 섬장암류), 쥬라기의 흑운모화강암 및 제4기의 현무암으로 구성된다. 알칼리 섬장암류는 각섬석-휘석 섬장암, 각섬석-흑운모 섬장암, 흑운-하석 섬장암, 흑운모 섬장암 및 석영-각섬석-휘석 섬장암 등을 포함한다. 후기 마그마 단계에서 수반되는 알칼리 교대작용에 의해 형성된 알칼리 교대암은 호암산 관입암체의 남쪽 가장자리를 따라 띠모양이나 불규칙한 맥상 및 렌즈상으로 Nb-Ta 광체를 이루고 있다. 산출되는 광석광물은 파이로크롤과 저어콘을 비롯하여 극소량의 콜럼바이트, 퍼규소나이트, 자철석, 형석, 휘수 연석, 티탄철석, 티타나이트, 인회석 및 모나자이트 등 이다. Nb, Ta, 희토류 및 방사성 원소(Th, U)를 함유하는 파이로크롤은 (1) 부화된 Ta, U 및 Ce, (2) 낮은 함량의 Ta 및 F (3) Th 또는 Ba의 부화 등으로 특징된다. 지화학적 특징과 광석의 구조 및 광물의 산출 특성으로 미루어 광화작용이 알칼리성 광화유체의 교대작용에 따른 것임을 알 수 있다.