• Bulletin of the Korean Chemical Society
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• 제34권12호
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• pp.3609-3614
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• 2013

Orthorhombic and hexagonal lanthanum(III) hydroxycarbonate ($LaCO_3OH$) and $Ln^{3+}$-doped $LaCO_3OH$ ($LaCO_3OH:Ln^{3+}$, where Ln = Ce, Eu, Tb, and Ho) powders were prepared by a hydrothermal reaction under ambient pressure and characterized by thermogravimetry, powder X-ray diffraction, infrared and luminescence spectroscopy, and field-emission scanning electron microscopy. The polymorph of $LaCO_3OH$ depended on the reaction temperature, inorganic salt additive, species of $Ln^{3+}$ dopant, and solvent. The calcination of orthorhombic $LaCO_3OH:Ln^{3+}$ (2 mol %) powers at $600^{\circ}C$ yielded a mixture of hexagonal and monoclinic $La_2O_2CO_3:Ln^{3+}$ powders. The relative quantity of the latter increased with decreasing ionic radius of the $Ln^{3+}$ dopant ion and increasing doping concentrations. On the other hand, the calcination of hexagonal $LaCO_3OH:Ln^{3+}$ (2 mol %) powders at $600^{\circ}C$ resulted in a pure hexagonal $La_2O_2CO_3:Ln^{3+}$ powder, regardless of the species of $Ln^{3+}$ ions (Ln = Ce, Eu, and Tb). The luminescence spectra of $LaCO_3OH:Ln^{3+}$ and $La_2O_2CO_3:Ln^{3+}$ were measured to examine the effect of their polymorph on the spectra.

• Transactions on Electrical and Electronic Materials
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• 제10권4호
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• pp.125-130
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• 2009

The clamping voltage characteristics and accelerated aging behavior of CoCrTb-doped Zn/Pr-based varistors were investigated for different sintering temperatures. The best clamping voltage characteristics were obtained for the varistors sintered at $1330^{\circ}C$, with a clamping voltage ratio (K) of 1.63 at a surge current of 5 A and 1.75 at a surge current of 10 A. The varistors sintered at $1330^{\circ}C$ exhibited the highest stability, with -0.1% in $%{\Delta}E_{1\;mA}$, -0.2% in $%{\Delta}{\alpha}$, and +15.5% in $%{\Delta}J_L$ for E-J characteristics under a stress state of 0.90 $E_{1\;mA/120^{\circ}C$ /24 h. Furthermore, it exhibited $%{\Delta}{\varepsilon}_{APP}$' of -0.7% and $%{\Delta}tan{\delta}$ of +5.7% for dielectric characteristics under the same stress state.

• 한국광학회:학술대회논문집
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• 한국광학회 1988년도 광학 및 양자전자학 워크샵
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• pp.127-131
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• 1988

In order to clarify the origin of perpendicular anisotropy in thermally evaporated TbFeCo amorphous thin films, we have investigated the effects of deposition angle on magnetic Kerr hysteresis loop, perpendicular magnetic anisotropy and internal stress depend strongly on the deposition angle and above a threshold value(30$^{\circ}$), the perpendicular anisotropy disapperars and the in-plane anisotropy appears. The measurement of internal stress is the major contribution to the perpendicular anisotropy. The measurements of Kerr hysteresis loops in the polar and the longitudinal directions show that as the deposition angle increases the polar kerr hystresis loop deteriorates while the longitudinal Kerr hystersis loop becomes prominent.

• Tuberculosis and Respiratory Diseases
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• 제78권1호
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• pp.1-7
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• 2015

Background: The incidence of tuberculosis (TB) in Korea is relatively high compared to the other Organisation for Economic Co-operation and Development (OECD) countries, with a prevalence of 71 per 100,000 in 2012, although the incidence is declining. Real-time polymerase chain reaction (PCR) has been introduced for the rapid diagnosis of TB. Recently, its advantage lies in higher sensitivity and specificity for the diagnosis of TB. This study evaluated the clinical accuracy of real-time PCR using respiratory specimens in a clinical setting. Methods: Real-time PCR assays using sputum specimens and/or bronchoscopic aspirates from 2,877 subjects were reviewed retrospectively; 2,859 subjects were enrolled. The diagnosis of TB was determined by positive microbiology, pathological findings of TB in the lung and pleura, or clinical suspicion of active TB following anti-TB medication for more than 6 months with a favorable response. Results: Sensitivity, specificity, and accuracy were 44%, 99%, and 86% from sputum, and 65%, 97%, and 87% from bronchoscopic aspirates, respectively. For overall respiratory specimens, sensitivity was 59%, specificity was 98%, and accuracy increased to 89%. Conclusion: Positivity in real-time PCR using any respiratory specimens suggests the possibility of active TB in clinically suspected cases, guiding to start anti-TB medication. Real-time PCR from selective bronchoscopic aspirates enhances the diagnostic yield much more when added to sputum examination.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2009년도 임시총회 및 하계학술연구발표회
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• pp.236-236
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• 2009

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.116.1-116.1
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• 2008

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2008년도 Asian Magnetics Conference
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• pp.90.1-90.1
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• 2008

• 센서학회지
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• 제6권1호
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• pp.63-71
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• 1997

ZnS:Mn/$ZnS:TbF_{3}$적층구조의 TFEL(thin-film eletroluminescent)소자를 제작하였으며, 이때 절연층으로 (Pb,La)$TiO_{3}$(이하PLT)와 $SiO_{2}$박막을 이용하였다. TFEL소자는 $78V_{rms}$의 문턱전압과 $100V_{rms}$의 인가전압에서 $400{\mu}W/cm^{2}$의 휘도를 나타내었다. TFEL소자의 발광스펙트럼은 450nm에서 630nm사이의 파장대를 보이고 있다. 제작된 TFEL소자는 컬러필터를 병용함으로서, 적 녹 청의 색상을 구현하는 TFEL소자로 활용할 수 있다.

• 한국광학회지
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• 제3권2호
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• pp.105-110
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• 1992

광자기 기록 박막의 자기 광학효과에 의한 미소 편광 회전각을 축정하기 위하여 편광 변조 방법을 이용하였다. 편광 변조 방법은 Faraday 회전자로 레이저광의 편광을 변조하고 phase sensitive detection방법을 써서 변조된 신호만을 선택적으로 검출하는 것이다. 본 실험에서는 진공증착법으로 제작된 TbFeCo박막과 RF 스퍼터링으로 제작된 iron garnet 다결정 박막의 자기 Kerr 회전 및 Faraday 회전 이력곡선을 이 방법으로 조사하였다. 그 결과 $0.25^{\circ}$정도의 미소한 회전각을 측정하였으며 특히 longitudinal Kerr 회전의 경우 $2.5\times10^{-3^\circ}$정도의 매우 작은 회전각도 측정할 수 있었다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 somma/kms meeting
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• pp.261-261
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• 2003