• 대한화학회지
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• 제24권6호
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• pp.452-456
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• 1980

용리액의 pH와 EDTA 농도변화에 따른 모나자이트 중의 희토류원소의 분리에 이어 수지통의 크기, 유츌속도 수지종류에 따른 분리를 약 10g 의 희토류를 흡착시킨 후 연구하였다. 같은 무게의 수지에서는 수지통의 높이가 높은 것이 낮은 것보다 분리도가 좋았고, 전 희토류를 용리하는데 필요한 용리액의 부피는 비슷하였다. 용리액의 유출속도를 1ml/min에서 2ml/min으로 증가시킨 결과 전 희토류를 완전히 용리시키는데 필요한 용리액의 부피가 10l 더 필요했고 분리도는 1ml/min일때 보다 나빴다. 그러나 용리시키는데 걸리는 시간은 약 6일 단축되었다. 수지의 입자가 25∼50 mesh의 Ambellite IR A-400의 수지를 이용하여 분리한 결과는 Dowex 1(50∼100 mesh)의 수지를 사용하여 분리한 결과보다 못하였다.

• 한국표면공학회지
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• 제50권3호
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• pp.206-211
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• 2017

$BiNbO_4:RE^{3+}$ (RE = Dy, Eu, Sm, Tb) phosphors were prepared by solid-state reaction at $1100^{\circ}C$ and their structural, photoluminescent, and morphological properties were investigated. XRD patterns exhibited that all the synthesized phosphors exhibited a triclinic system with a dominant (210) diffraction peak, irrespective of the type of activator ions. The surface morphologies of rare-earth-ion-doped $BiNbO_4$ phosphors were found to depend strongly on the type of activator ions. The $Eu^{3+}$ and $Dy^{3+}$ doped $BiNbO_4$ phosphors revealed a strong red (613 nm) emission resulting from the $^5D_0{\rightarrow}^7F_2$ transition of $Eu^{3+}$ and a dominant yellow (575 nm) emission originating from the $^4F_{9/2}{\rightarrow}^6H_{13/2}$ transition of $Dy^{3+}$ respectively, which were the electric dipole transitions, indicating that the activator ions occupy sites of non-inversion symmetry in the $BiNbO_4$ phosphor. The main reddish-orange emission spectra of $Sm^{3+}$-doped $BiNbO_4$ phosphors were due to the $^4G_{5/2}{\rightarrow}^6H_{7/2}$ (607 nm) magnetic dipole transition, indicating that the $Sm^{3+}$ ions were located at inversion symmetry sites in the $BiNbO_4$ host lattice. As for $Tb^{3+}$-doped phosphors, green emission was obtained under excitation at 353 nm and its CIE chromaticity coordinates were (0.274, 0.376). These results suggest that multicolor emission can be achieved by changing the type of activator ions incorporated into the $BiNbO_4$ host crystal.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.352.2-352.2
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• 2016

In recent times, much effort has been concentrated on trivalent rare-earth ions activated ceramics or oxide phosphors to develop display industries due to their promising applications in optoelectronic devices and field-emission displays. To prepare efficient phosphors, citrate sol-gel method is one of the best synthetic methods. Green and blue emissive CaLa2ZnO5:RE3+ nanocrystalline materials are synthesized by a citrate sol-gel method. After the samples annealing at $1100^{\circ}C$, morphological and structural properties are investigated by scanning electron microscope images and X-ray diffraction patterns, respectively. At low electron beam voltage of <5 kV, the visible photoluminescence properties are obtained. Various concentrations of the RE3+ ions exhibited their characteristic emission peaks at different excitation wavelengths, respectively. Similarly, at high electron beam anodic voltage, the cathodoluminescence properties are studied as a function of acceleration voltage and filament current. The chromaticity coordinates are calculated for the optimized CaLa2ZnO5 nanocrystalline luminescent materials.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.643-643
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• 2013

Recently, synthesis of low-dimensional nanostructures is gaining more importance due to their structural properties and growing potential applications. On the other hand, luminescent materials doped with rare earth ions have drawn immense attention. The commercial phosphors are based on many host materials. Among them, tungstates are being currently investigated by many research groups owing to a wide range of applications. Tungstates are formed by different metal cations (e.g., SrWO4, Na2WO4, NiWO4, Cr2WO6, and ZrW2O8) and their structure depends on the size of the metal cation. Tungstates with large bivalent cations (${\gg}0.1\;nm$) have the scheelite structure and the wolframite structure with smaller ions (＜0.1 nm). Strontium tungstate has the scheelite structure which is tetragonal with space group I41/a. The luminescent properties of the tungstate have been extensively explored in application fields such as sensors, detectors, lasers, photoluminiscent devices, photo catalysts, etc. In this work, we synthesized SrWO4 phosphors with different Eu3+ concentrations by using a facile route. The morphology was analyzed by using a field-emission scanning electron microscope, which exhibits the spherical shape. Transmission electron microscope image revealed the spheres composed of nanoparticles. X-ray diffraction patterns confirmed their tetragonal shape. The photoluminescence excitation and emission spectra were analyzed by varying the Eu3+ concentration, which shows a dominant red emission.

• 한국광학회:학술대회논문집
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• 한국광학회 2000년도 제11회 정기총회 및 00년 동계학술발표회 논문집
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• pp.96-97
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• 2000

Incoherent broadband optical sources have been applied in various areas such as a light source for optical device characterization, fiber-optic gyroscopes$^{(1)}$ , and spectrum sliced light source in wavelength division multiplexing (WDM) system$^{(2)}$ . To utilize the inherent low loss in silica optical fibers, various types of incoherent light sources are being developed. Among the light sources, the amplified spontaneous emission (ASE) from a rare earth doped fiber has benefits in temperature stability, high output power, low polarization dependence over semiconductor diodes$^{(3)}$ . Recently erbium doped fibers (EDF) have been intensively researched for ASE sources as well as optical amplifiers$^{(4)}$ . The spectrum of ASE from an EDF, however, is limited in the 1520~1560 nm range in conventional configurations. In this letter we described a new broadband ASE source which included both the conventional ASE band of Er$^{3+}$ ion, 1520nm~1560nm and ASE band from Tm$^{3+}$ ions that extends the bandwidth further. For the first time, to the best knowledge of authors, a fiber ASE source based on the energy transfer between Er$^{3+}$ and Tm$^{3+}$ ions in the range of 1460~1550 nm, has been demonstrated using a single 980nm pump laser diode. (omitted)omitted)

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.546-546
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• 2013

Zinc silicate ($Zn_2SiO_4$) has been identified as a suitable host material for a wide variety of luminescent activators, such as transition metal and rare earth elements. In particular, manganese-activated $Zn_2SiO_4$ exhibits highly efficient photoluminescenceand cathodoluminescence, which allows this material to be used in fluorescent lamps and display applications. In this study, we investigated the green and yellow luminescence from Mn-doped $Zn_2SiO_4$ thin films that were synthesized using radio frequency magnetron sputtering followed by annealing at $600{\sim}1,200^{\circ}C$ The refractive index of the $Zn_2SiO_4$: Mn films showed normal dispersion behavior. It was found that the $Zn_2SiO_4$: Mn films annealed at $800^{\circ}C$ ossessed a mixture of alpha and beta phases. The obtained photoluminescence spectrum consisted of two emission bands centered at 525 nm in the green range and 574 nm in the yellow range. The green luminescence originates from the divalent Mn ions in alpha phase of $Zn_2SiO_4$, while the yellow luminescence comes from the divalent Mn ions in beta phase. The films annealed at and above $900^{\circ}C$ xhibited only the alpha phase. The broad PL excitation band was observed ranging from 220 to 300 nm with a maximum at around 243 nm.

• 분석과학
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• 제9권3호
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• pp.244-252
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• 1996

라탄족(III) 이온과 methylthymol blue 및 cetyltrimethylammonium bromide의 삼성 분계에 라탄족(III)-methylthymol blue 착물의 분광학적 특성을 조사하고 이를 토대로 흐름주입법에 의하여 라탄족(III) 이온들을 정량하였다. pH 5.8인 cetyltrimethylammonium bromide 용액에서 라탄족(III)-methylthymol blue 착물의 최대 흡수 파장은 대략 635nm 영역이며, 몰흡광계수는 $^{64}Gd$(III)로부터 $^{70}Yb$(III)에 대해 $4.51{\sim}6.11{\times}10^4Lmol^{-1}cm^{-l}$였다. Cetyltrimethyl-ammonium bromide 존재하에서, 이들 착물의 조성비는 1:2였다. 흐름주입법에 의한 란탄족(III) 이온의 검정곡선은 0.1~0.4ppm 범위에서 Beer의 법칙에 따른다. 시료의 분석속도는 약 60개 $hr^{-1}$이었다. 여러 양이온과 음이온의 영향을 조사한 결과 tartrate나 citrate 같은 리간드 음이온과 대부분 전이원소, 희토류 원소들에 의해 방해를 받았으며, 이들 양이온들은 란탄족(III) 이온을 정량하기 전에 사전 제거가 필요하다.

• The Korean Journal of Ceramics
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• 제5권4호
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• pp.375-378
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• 1999

In tho XRD study of $56ZrF_4 \cdot34BaF_2 \cdot4AIF_3 \cdot(6-x)LaF_3 \cdotxLnF_3$ glassdLn=Ce, Nd, Gd, Th), halo pattern charactarktic fo an amorphous sample appeared. When the halo peak angle ($\theta_p$) was converted into a wavenumber with $Qp=4\pi sinG\pi/\lambda(\lambda$ is the wavolongth of the radialion used), it was found that the Qp values varied almost liuearly with the concentration 01 $LnF_3$. The emissiou spect1.a of $Ce^{3-}$-containing fluoride glasses nnder 273 nm excitation had a peak maximum at ea. 300 nm $(Ce^{3+}$ 5d-4f- transition). The maximal intensity of the fluorescence was observed when the $CeF_3$, content was extremely low (ca. 1 mol%j. DTA measurement revealed tbat these fluoride glasses had two crystallization temperatures. In $56ZrF_4. 34BaF_2. 4NF_3. (6-x)LaF_3 .xNdF_3$ glasses, the actmation energies of crystallization obtained from a Kssinger plot were 1.7 and 5.0 eV for the glass with x=2, and 1.9 and 5.6 eV for the glass with x=4.

• 대한화학회지
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• 제27권2호
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• pp.127-132
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• 1983

톨루엔의 동종간 주고 받기 반응에 대한 ZSM-5 촉매의 활성은 양이온의 종류, 이온교환을 그리고 반응온도에 좌우된다. 활성은 알카리금속, 알카리토금속, 수소, 희토류 금속 이온이 교환되는 순서로 증가하며 이온 교환도가 증가함에 따라 감소한다. 이온 교환된 ZSM-5 촉매중에서 Cs-ZSM-5만이 p-크실렌에 대해 우세한 선택성을 나타내는데 p-크실렌에 대한 선택성은 세슘이온 교환율이 증가할 수록 반응온도가 감소 할수록 증가한다. 이러한 현상은 ZSM-5의 세공 교차점에 있는 세슘이온이 부분적으로 세공을 막아주는 형상 선택성으로 해석된다.

• 한국세라믹학회지
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• 제29권11호
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• pp.851-854
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• 1992

It was grown ZrO2:10 mol% Y2O3 single crystals doped with 1 wt% of rare earth metal ion (Ce, Pr, Nd, Er, Eu) by Skull Method. Grown crystals showed Ce:orange-red, Pr:golden-yellow, Nd:lilac, Er:pink, Eu:light pink due to dopant effect. It was examined color centers in light absorption pattern of visible region (λ= 300~700 nm); in as grown samples, absorption by Ce4+, (Pr4+, Pr3+), Nd3+, Er3+, Eu3+ ions were important, and in samples after vacuum annealing, decrease of absorption by Pr4+ ion and increase of absorption by Pr3+ ion was important, and absorption by Ce3+, Eu2+ was important due to reduction of activator.