• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1071-1074
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• 2003

The effects of ZnS insertion on the characteristics of CaS:Pb phosphor were investigated. The intensity of photoluminescence of ZnS inserted CaS:Pb excited by 347nm were increased while that excited by 254nm was unchanged, compared to those of CaS:Pb thin film. The electroluminescent display having ZnS inserted CaS:Pb showed lower threshold voltage and higher efficiency than those of CaS:Pb ELD device.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.149-150
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• 2000

Lead-doped calcium sulfide(CaS:Pb) thin film electroluminescent devices were deposited using atomic layer deposition(ALD). CaS:Pb is a very promising blue phosphor showing very high luminance and the color coordinate close to the blue of cathode ray tube. The luminance, $L_{25}$, of CaS:Pb(1.6 mol.%) EL device was higher than 80 $cd/cm^2$ at a driving frequency of 60Hz. The color coordinates of blue EL emission of CaS:Pb deposited by ALD are consistent with the Pb concentration ranging from approximately 0.5 to 3 mol.%.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.795-801
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• 1994

The BiPbSrCaCuO superconductor was fabricated by diffusion of The dual layer composed of SrS12TCaS11TCuS12TOS1xT in upper layer and BiS12TPbSI0.3TCuS12TOS1yT in lower layer, and varified growh-mechanism of BiPbSrCaCuO superconducting phase. And, we produced optimum conditions of spread volume and each stage of sintering time were upper layer:Lower layer=1:0.2, 1:0.4, 1:0.6 and 24hr., 120hr., 210hr. From the result, the optimum conditions are spread volume(Upper layer:Lower layer=1:0.6), sintering time(210hrs.) at 820$^{\circ}C$.The BiPbSrCaCuO superconductor, fabricated optimum condition, showed zero resistance at critical temperature of 70k.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.04b
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• pp.93-96
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• 2002

원자층증착법으로 제조한 청색 CaS:Pb 박막 형광체에 대한 열처리 및 전자빔 조사 효과찰 연구하였다. CaS:Pb 형광 박박의 열처리는 500 - $700^{\circ}C$ 온도범위에서 급속 열처리 공정으로 수행하였고, 1 kV, $20{\mu}A/cm^{2}$ 조건의 전자빔을 연속적으로 조사하여 열화를 가속시킨 후 처리 전, 후의 재료 및 cathololuminescence (CL) 특성을 비교 분석하였다. 원자층증착법으로 성장한 CaS:Pb 박막은 화학적 조성과 결정성이 우수하여 후속 열처리에 의해 발광특성이 크게 증가하는 경향을 보이지 않았으며, 전자빔에 의한 열화 정도는 판매되고 있는 형광체에 비하여 오히려 적었다. CL 강도가 초기값의 50%로 감소할 때까지 전자빔을 조사한 후에도 주목할만한 결정성 및 조성의 변화는 관찰되지 않았으나 전자빔 조사에 의해 표변에 두께 10 nm 내외의 탄소오염층이 형성됨을 알 수 있었다.

• Electrical & Electronic Materials
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• v.9 no.7
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• pp.680-689
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• 1996

SrCaCuO와 BiPbCuO 화합물로 이루어진 이중층시료가 만들어 졌으며, 소결과정에서 나타나는 확산과 입자간의 상호작용으로 108K의 임계온도를 나타내었다. 이 시료는 820.deg. C에서 0-210 시간동안 소결되었다. 초전도체의 생성, 성장메카니즘과 임계온도의 관계가 연구되었으며, 최적조건은 820.deg. C에서 210시간 소결하고 SrCaCuO와 BiPbCuO의 도포비가 1:0.6인 시편에서 나타났다. 또한 이중층시료에서 가장 좋은 조성비는 S $r_{2}$C $a_{2}$C $u_{2}$ $O_{x}$와 B $i_{1.9}$P $b_{0.5}$C $u_{3}$ $O_{y}$ 이었다.다.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.446-452
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• 2008

This study was conducted to research the biosorption characteristics using algae, Spirulina platensis, for the removal of Pb and Cu ions in wastewater. Both of free algal cell and immobilized algae by Ca-alginate were used as bioadsorbent, and experiment was proceed in batch reactor for Pb and Cu ions removal, respectively. In the biosorption of Pb and Cu ions by free Spirulina platensis cell, the adsorption equilibrium reached within 20 minute. The higher adsorbed amount of Pb and Cu was shown as increasing of initial concentration of Pb and Cu, and pH of solution, respectively, and the optimum pH was 4.5$\sim$5.0. Under the conditions of initial concentration of Pb or Cu are 200 mg/L, the maximum amounts of Pb and Cu adsorbed to the unit weight of Spirulina platensis were 86.43 and 57.02 mg/g, respectively, and these values were 1.94 and 1.48 times higher than those of activated carbon under same conditions, respectively. The biosorption kinetics of Pb and Cu ions by free Spirulina platensis cell fitted very well to the Freundlich and Langmuir isotherm. The maximum amount of Pb or Cu adsorbed to the unit mass of adsorbent by the Langmuir isotherm($q_{max}$) represented as 95.24 and 62.50 mg/g, respectively. The FT-IR results of free Spirulina platensis biomass showed that biomass has different functional groups and these functional groups are able to react with metal ions in aqueous solution. In the biosorption of Pb and Cu ions by Ca-alginate immobilized algae Spirulina platensis, the adsorption equilibrium reached within 40 min. and observed a little diffusion limitation differed from the free algal cell adsorption.

• KSBB Journal
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• v.14 no.5
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• pp.611-615
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• 1999

Biosorption of Pb was evaluated for Sargassum sagamianum. An adsorption equilibrium was reached in about 1 hr. The uptake capacity of Pb was 224.5 mg Pb/G biomass. The adsorption parameters for Pb were determined according to Langmuir and Frueundlich model. With increasing pH, more negative sites are becoming available for adsorption of Pb. When Ca and Mg concentration increases in Pb solution, Pb was selectively adsorbed. The Pb adsorbed by S. sagamianu could be desorbed by desorption process and the efficiency from 0.1M HCl, 0.1M HNO$_3$and 0.1M EDTA was above 95%. S. Sagamianum was reused 6 times and the total uptake was 736.8 mg Pb/g biomass.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.29-30
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• 2000

CaS:Pb thin film used as phosphor layer in electroluminescent devices were deposited by an atomic layer deposition (ALD). The photoluminescence emission and excitation spectra were measured at 5 and 300K for the $CaS:Pb^{2+}$ phosphors with different Pb concentration from 0.001 at.% to 0.648 at.%. The emission spectra of these samples were characterized as UV emission and blue emission with the center of peak around 360 and 425nm, respectively. The UV emission was dominant at the low $Pb^{2+}$ concentration of 0.001 at%, whereas with increase of Pb concentration, the blue emission became a major component and to longer wavelength.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.333-337
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• 1999

Biosorption of Pb to Sargassum horneri was evaluated. An adsorption equilibrium was reached in about 15 min. for Pb and Pb uptake was 185.5 mg Pb/g biomass. When Ca and Mg concentration increases in Pb solution, Pb was selectively adsorbed. The Pb adsorbed by S. horneri could be recovered by desorption process, and the desorption efficiency of Pb by 0.1 M HCl, 0.1 M $HNO_3$, and 0.1 M EDTA was above $95\%$, whereas the elution by 0.1 M NaOH was less efficient in the desorption of Pb. S. horneri was reused 6 cycle repeatedly after adsorption/desorption and the sum of uptake was 636.6 mg Pb/g biomass.

• Journal of the Korean Ceramic Society
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• v.37 no.3
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• pp.240-246
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• 2000

The microwave dielectric properties of the complex perovskite (Pb0.5Ca0.5)(Fe0.5Ta0.5)O3 ceramics were investigated with the porosity and the dielectric mixing rule. Assuming that the specimens were mixtures of real dielectrics and pores, with 3-0 connectivity, the ionic polarizabilities modified by Maxwell's equation were more close to the theoretical values rather than those modified by Wiener's equation in porous specimens. The theoretical dielectirc loss were obtained with the infrared reflectivity spectra from 50 to 4000cm-1, which were calculated by Kramers-Kronig analysis and classical osciallator model. The relative tendency of dielectric loss calculated from the theoretical value and Maxwell's equation in the specimens with different porosities was in good agreement with the one by the post resonant method.