• 제목/요약/키워드: Yttrium

검색결과 400건 처리시간 0.023초

$Al_2O_3$조성변화에 따른 YIG의 주파수 및 자기특성 (The frequency and magnetic characteristics of YIG with the variation of $Al_2O_3$ additions)

  • 홍기원;김명호;장경욱;이준웅
    • E2M - 전기 전자와 첨단 소재
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    • 제8권6호
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    • pp.787-794
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    • 1995
  • To improvement the magnetic and frequency properties of YIG(Yttrium-Iron Garnet) in microwave region, it is investigated that the effect of $Al^{3+}$ ions on magnetic and frequency characteristics of YIG, using samples of basic YIG composition( $Y_{3}$F $e_{5}$ $O_{l2}$) added with A1$_{2}$ $O_{3}$ from 0 to 2.5 [mol%]. The measurment is conducted mainly for the structural properties and magnetical properties. The structural properties is measured using SEM(Scanning Electro Microscope), EDX(Energy-dispersive X-ray spectrometer) and XRD(X-ray diffraction equipment). The magnetical properties is measured with B-H curve tracer and impedance analyzer. As a result, it is confin-ned that the effect of eddy current loss is minimized while maintaining high saturation flux density of YIG, when YIG is added with 0.5 [mol%] of A1$_{2}$ $O_{3}$.>.>.

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Screen printing 방법에 의한 후막형 Bi-Pb-Sr-Ca-Cu-O 초전도체의 소결조건과 기판의 초전도성에 미치는 영향 (Effects of Substrate and Sintering Conditions on the Properties of Screen Printed Bi-Pb-Sr-Ca-Cu-O Superconduction Thick Films)

  • 김혜동;임호빈
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1990년도 추계학술대회 논문집
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    • pp.26-30
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    • 1990
  • Bi$\_$0.7/Pb$\_$0.3/Sr$_1$Ca$_1$Cu$\_$1.8/Ox thick films were screen printed on magnesia(MgO), silver and yttrium stabilized zirconia (YSZ) substrates and were sintered in a boat with cover to prevent the evaporation. The high-Tc phase increase and the low-Tc phase and Ca$_2$PbO$_4$ decrease with an increase in sintering temperature from 835$^{\circ}C$ to 860$^{\circ}C$. YSZ substrate interact strongly with the oxide resulting in poor superconductor, while the Ag and MgO substrates were satisfactory to make screen printed superconductors. The Bi$\_$0.7/Pb$\_$0.3/Sr$_1$Ca$_1$Cu$\_$1.8/Ox thick films screen printed both on Ag and MgO substrates show high Tc phase of ~85% and Tc of 96K.

높은 비 직선성을 갖는 프라세로디윰계 ZRO 바리스터 (Praseodymium-Based ZnO Varistor with High Nonlinearity)

  • 정순철;이외천;남춘우
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1997년도 추계학술대회 논문집
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    • pp.505-509
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    • 1997
  • Praseodymium-based ZnO varistor containing 2.0mol% and 4.0mol% $Y_2$O$_3$ were fabricated, respectively and its microstructure and electrical properties were investigated. Yttrium distributed nearly in the grain boundaries and cluster phase at nodal point but more in cluster phase. The average grain size of the 2.0%mol% and 4.0mol% $Y_2$O$_3$-added samples was 14.8${\mu}{\textrm}{m}$ and 8.6${\mu}{\textrm}{m}$, respectively. Compared to 2.0mol% $Y_2$O$_3$, 4.0mol% $Y_2$O$_3$-added varistors showed very good I-V characteristics exhibiting highly nonlinear exponent(87.4) and low leakage current(46.7nA). These results are the important experimental fact in this paper.

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Bi, Ce가 도핑된 YAG계 형광체의 발광 특성 (Luminescence properties of Bi, Ce activated YAG based phosphor materials)

  • 김세헌;한태수;이상근;정천기
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.525-528
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    • 1999
  • The luminescence of bismuth and cerium doped yttrium aluminum based Phosphors $Y_{3}$/Al$_{5}$/O$_{12}$ and (Y$_{0.8}$/Gd$_{0.2}$)$_3$Al$_{5}$/O$_{12}$ prepared by a solid-state reaction method were studied. These samples which were fired at 1, 20$0^{\circ}C$ show the characteristic X-ray diffraction patters for the main phase(420) of YAG. This study indicates that the both flux and remained bismuth after the firing phosphor materials give rise to affect the photoluminescence properties. Therefore, it was investigated that both the XRD patterns arid the PL properties were affected by the controlling experimental process variables.riables.les.

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고출력 microchip laser용 Yb:YAG 단결정의 결정성장 및 분광 특성 (Crystal Growth and Spectroscopic Properties of Yb:YAG Crystals for High Power Microchip Laser Applications)

  • 유영문;정석종;이성영;김병호
    • 한국광학회:학술대회논문집
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    • 한국광학회 2000년도 하계학술발표회
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    • pp.246-247
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    • 2000
  • Yb$^{3+}$ 이온은 InGaAs LD 및 Ti:sapphire 레이저로 펌핑할 수 있는 940 nm에서의 흡수대를 가지고 있고, 1.03 $mu extrm{m}$의 형광방출 특성을 가지고 있으며, 지금까지 알려진 1 $\mu\textrm{m}$ 파장대의 레이저 활성이온 중에서 가장 적게 열을 발생하는 특성을 가지고 있음이 알려져 최근에는 Yb$^{3+}$ 이온을 첨가한 여러 가지 레이저 매질이 연구되고 있다.[1] 그 중에서도 Yb$^{3+}$ ion doped yttrium aluminum garnet (Yb:YAG) 단결정은 충분하게 넓은 흡수선폭, 좋은 열광학적 특성, 고출력 작동을 하게 하는 stokes shift, 그리고 LD에 의한 펌핑을 가능하게 하는 940 nm 영역에서의 흡수 및 긴 여기시간을 가진 이상적인 매질로 알려져 있다.[2] 이러한 특성으로 인해 Yb:YAG 단결정은 femtosecond 레이저 등 각종 레이저 시스템의 소형화[3]를 가져왔으며, 레이저 결정의 양산 가능성 및 레이저 기기의 소형화에 따르는 시스템의 가격 감소가 가능하므로 Yb:YAG microchip 레이저는 향후 고출력 레이저 기기 산업의 중추가 될 것으로 기대된다. (중략)

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A Quantitative Determination of Overlapped Chromatographic Peaks of Dysprosium and Yttrium Using Target Transformation Factor Analysis

  • Song Joon Myong;Lee Chul;Chung Koo Soon
    • Bulletin of the Korean Chemical Society
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    • 제15권1호
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    • pp.74-77
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    • 1994
  • Rare earth elements (REE) were individual separated by applying the gradient elution via HPLC using ${\alpha}-hydroxyisobutyric$ acid (HIBA) as an eluent. However, the overlap of Y and Dy peaks was too severe to obtain the resolution of these two peaks. The target transformation factor analysis (TTFA) was applied to resolve the elution peaks of Y and Dy. [A]$_{raw}$ formed from the absorbances of mixed solution was factor analyzed. The abstract factor analysis(AFA) was used to determine the number of components that contributed to the poorly resolved peaks. The error theory in the AFA showed that the number of components was 2. The test vectors which correspond to pure component were selected from the standard solutions of Y and Dy. TTFA was accomplished by target testing. The results showed that the resolution of two peaks as well as the determination of Y and Dy were possible by the factor analysis.

An XPS Study of YBaCuO Compounds

  • Myung-Mo Sung;Yunsoo Kim
    • Bulletin of the Korean Chemical Society
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    • 제11권2호
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    • pp.118-123
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    • 1990
  • X-ray photoelectron spectra have been obtained and comparisons have been made for 1-2-3 and 2-1-1 phases of YBaCuO compounds. The photoelectron binding energies of all the constituent elements are consistently larger for the 2-1-1 phase than for the 1-2-3 phase. The peak intensities reflect different stoichiometries of the two phases. For the superconducting 1-2-3 phase, its degradation in air and interaction with water and carbon dioxide were examined by taking core level spectra of all the elements. It appears that yttrium is the most affected by exposure to air, since it undergoes a rapid change to carbonate when water and subsequently carbon dioxide are introduced.

Formation Process of a Red Phosphor, $Y_2O_2S:Eu^{3+}$

  • Mho, Sun-Il;Chang, So-Young;Jeon, Chai-Ik;Pyun, Chong-Hong;Choi, Q. Won;Kim, Chang-Hong
    • Bulletin of the Korean Chemical Society
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    • 제11권5호
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    • pp.386-390
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    • 1990
  • Yttrium oxysulfide incoporated with europium has been prepared by direct heating the mixture of $Y_2O_3,\;Eu_2O_3,\;NaOH(or\;Na_2CO_3)$, and S. The reaction of the mixture at low temperatures and treatment at higher temperatures are studied. The formation of $Y_2O_2S$ is completed at lower temperature (ca. 500$^{\circ}C$) and incorporation of $Eu^{3+}$ into $Y_2O_2S$ lattice proceeds at higher temperature (above 1000$^{\circ}C$) along with crystal growth. Small amount of the unknown phase considered to be $Y_2O_2S_2$ is formed along with $Y_2O_2S$ in the temperature range from 400$^{\circ}C$ to 460$^{\circ}C$.

Adsorption and separation behaviors of Y(III) and Sr(II) in acid solution by a porous silica based adsorbent

  • Wu, Hao;Kawamura, Taiga;Kim, Seong-Yun
    • Nuclear Engineering and Technology
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    • 제53권10호
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    • pp.3352-3358
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    • 2021
  • Aiming at selective adsorption and separation of Y(III) from the Y(III)-Sr(II) group in acid solution, a silica-based TODGA impregnated adsorbent [(TODGA+1-dodecanol)/SiO2-P-F600] has been prepared. Batch adsorption experiments were conducted under the effect of contact time, acid concentration, solution temperature, and adsorption capacity etc. Chromatography recovery of more than 90% Y(III) was successfully achieved under elution with 0.01 M DTPA solution in nitric acid adsorption system, and 0.1 M HCl solution in hydrochloride adsorption system, respectively.

Radiation segmentectomy for gastric leiomyosarcoma hepatic metastasis

  • Roh, Simon
    • 대한종양외과학회지
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    • 제14권2호
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    • pp.142-145
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    • 2018
  • Metastases to the liver can be found in various malignancies, most commonly originating from the colon, rectum, pancreas, stomach, esophagus, breast, lung, and melanoma. Surgical resection of liver metastasis is generally considered to be the definitive therapy fore cure. However, many patients are unable to undergo surgical resection due to medical comorbidities or multifocal extent of malignant disease affecting the liver. Among patients not eligible for surgery, other therapies exist for treatment in order to down stage the disease for surgical resection or for palliation. Radioembolization of hepatic metastases has shown to improve outcomes among patients with variety of malignancies including more common malignancies such as colorectal cancer. Yttrium-90 (Y-90) radioembolization has been successfully used in the management of hepatic metastases. A small series of metastatic sarcoma to the liver treated with radioembolization showed a promising response. We report a case of metastatic gastric leiomyosarcoma to the liver treated with Y-90 glass microspheres therapy using the radiation segmentectomy approach, previously described for hepatocellular carcinoma.