• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.36-36
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• 2007

$R_2O_3$(R=Bi, B)-RO(R=Ba, Zn)를 주성분으로 하는 Pb-free유리프리트에 높은 굴절률을 가지고 있는 $TiO_2$ filler를 첨가하여 PDP용 백색유전체를 제조하였다. $TiO_2$ type, 함량에 따른 백색유전체로의 반사율 및 유전 특성을 조사하였다. 백색유전체를 소성한 결과 rutile과 anatase를 중량비로 75:25로 혼합하여 $520^{\circ}C$에서 소성한 경우 밀도 및 수축율의 변화를 거의 나타나지 않았다. 그러나 $TiO_2$함량이 15wt.%를 혼합하여 첨가했을 경우 반사율은 높고 접합특성 또한 우수하였다. 또한, 유전상수는 $TiO_2$첨가량이 증가함에 따라 증가하는 경향을 나타내었다.

• Korean Journal of Materials Research
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• v.11 no.4
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• pp.305-311
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• 2001

$PbO-B_2O_3-SiO_2-Al_2O_3$, system was investigated for optical, thermal and electrical properties of transparent dielectric. We also studied the reaction between transparent dielectric and transparent electrode(Indium Tin Oxide, ITO) during firing. For the evaluation of properties, dielectrics were prepared under the conditions fired at 520~58$0^{\circ}C$ with 12$\mu\textrm{m}$ thickness. In the reaction between dielectrics and electrode(ITO), In ions diffused into dielectric layer, while Sn ion diffusion was not observed. The coefficient of thermal expansion, the dielectric constant, the glass transition temperature and the transmittance of the dielectric were greatly dependent on PbO content. The increase of the coefficient of thermal expansion and the dielectric constant were monitored by increasing PbO, while the glass transition temperature and the transmittance were decreased. With the increased $Al_2O_3/B_2O_3$ ratio, the coefficient of thermal expansion and the transmittance were decreased, while the dielectric constant was increased. The glass transition temperature did not change significantly.

• Electrical & Electronic Materials
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• v.7 no.6
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• pp.496-503
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• 1994

In recent years Sol-Gel processing provides an interesting alternative method for the fabrication of ferroelectric thin layers and powder. PZT powder was prepared from an alkoxide-based solution by a Sol-Gel method. Gelation of synthesized complex solutions, microstructure, thermal analysis and crystallization behaviors of the calcined powder were studied in accordance with a water content and a catalyst. Especially gelation and crystallization behavior were analysed with the change of pH. The gelation time decreased as the pH of the mixed solution increased. For PZT powder with 650.deg. C heat treatment, 100% perovskite phase was formed by using either acidic or basic catalyst. By using either acidic or basic catalyst, we were able to get very fine powders of uniform shape with an average particle size of 0.8-1.mu.m.

• Journal of Conservation Science
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• v.33 no.3
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• pp.215-223
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• 2017

The purpose of this study is to reveal the characteristics, correlations, and colorant materials of those using the chemical compositions of 30 glasses excavated from the Sarari hall of the Mireuksaji stone pagoda, and to determine the correlations between them and other glass excavated from the Wanggungri site. The results of the chemical analysis of the 11 glass beads show that they are a soda glass group with high contents of $SiO_2$ and $Na_2O$; these can be further subdivided into soda-alumina groups ($Na_2O-Al_2O_3-CaO-Si_2O$). The characteristics of the stabilizer are classified as being of the high alumina glass group (LCHA), except for two glasses. It was concluded that colorant materials affected the coloring for glass beads by various components including Ti, Mn, Fe, Cu and Pb. In addition, we examined six lead glasses which are glass plate and unknown fragments that are of a common lead glass system ($PbO-SiO_2$) with respect to the average contents of PbO (70wt.%) and $SiO_2$ (30wt.%). As a result of comparing these relics with those of the glass beads excavated by Wanggungri, there is a similarity in that they belong to the soda glass group. However, the contents of $Na_2O$ are relatively higher than that of the glass beads in the Mireuksaji pagoda, and most of relics include glasses with a low content of $K_2O$ and CaO. In addition, the PbO and $SiO_2$ contents are slightly different in the lead glass. It seems that the glass relics made at two different sites may have used different raw materials or techniques.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.10
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• pp.17-23
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• 1992

A ($Pb_{1-x}Ca_{x})ZrO_{3}$ system which has a high dielectric constant, low dielectric loss and temperature coefficient was investigated. For sintering temperatures above 1350$^{\circ}C$ the microstructures of sintered bodies were unchanged regardless of the amount of CaO. The dielectric constant and dielectric loss decreased and the temperature coefficient varied from positive to negative with the increasing amount of CaO. For the CaO content of 0.37, i.e. ($Pb_{0.63}Ca_{0.37})ZrO_{3}$, the ceramic showed very good dielectric properties such as ${\varepsilon}_1$=100, Q > 1200 at 3GHz, and T$_f$=$\pm$3ppm/$^{\circ}C$.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.256-259
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• 1999

The effects of Pr doping on structural and superconducting properties of (Pb$_{0.5}$V$_{0.5}$)Sr$_2$(Ca$_{1-x}$Pr$_x$)Cu$_2$O$_z$ have been studied. We have observed systematic variation of lattice parameters with increasing Pr content. A maximum Tc of about40 K has been observed in this system. The correlation between the crystal structure and superconductivity has been addressed.

• Journal of the Korean Ceramic Society
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• v.33 no.11
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• pp.1195-1202
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• 1996

To prepare the dielectric thin films of (Pb1-xSrx)TiO3 (x=0.1, 0.2, 0.3, 0.35, 0.5) by the sol-gel process titanium (IV) isopropoxide (Ti[OCH(CH3)2]4) and Pb Sr, acetate were used therefore the thin films were fabricated by dip-coating method. Stability of the sol decreased with addition of Sr content thin films could be fabricated up to 35mol% Over this range precipitation of sol occured thin films couldn't be obtained. Transmittance of thin films at visible range decreased with the increase of heat-treatment temperature but exhibited transmit-tance above 60% in all case. Moreover transmittance of thin films at visible range slightly increased with of addition of Sr,. When thin film containing 30 mol% srontium was heated at 600℃ the best perovskite phase was obtained. The dielectric constant (ε) was 280 and dielectric loss factor (tan δ) was 0.021 and curie tempera-ture (Tc) decreased with the increase of addition of Sr.

• Journal of the Korean Ceramic Society
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• v.20 no.3
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• pp.250-254
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• 1983

The effects of the various amount of $CeO_2$ $MnO_2$ and $Fe_2O_3$ added to the high lead-silicate glasses on the X-ray induced coloration were studied. The light transmissions and chromaticities of the glasses before and after exposing to X-ray radiation were measured to investigate the effects by additivies. The results are as follows ; 1. High lead-silicate glass added $CeO_2$ or $MnO_2$ has a little effect on the transmission but has a considerable effect on the chromaticity. The chromaticies of 56.6wt% PbO content glasses were changed as 3-7 times as those of 28.3wt% PbO content glasses. 2. By the X-ray irradiation glasses containing 0.2-0.5wt% $CeO_2$ were changed the least in chromaticity that is the most effective in preventing the X-ray induced coloration. 3. By X-ray irradiation $MnO_2$ reduced the transmissions and showed purple coloration. 4. Transmission change amounts of the glasses added $CeO_2$ and $Fe_2O_3$ were less than those of the glasses added $CeO_2$ alone by X-ray irradiation.

• Journal of the Korean Ceramic Society
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• v.40 no.9
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• pp.855-858
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• 2003

When the PbO-based flux system is used in the Liquid Phase Epitaxy (LPE) method for Yttrium Iron Garnet (YIG) thick film, the effect of Pb ions incorporated into the grown crystal; increase the lattice parameter, changed the uniaxial magnetic anisotropy constant (Ku) or conductance of grown film. It exerts a bad influence on physical property such as increasing optical absorption of grown film. The content of the Pb ion in crystal was decreased by volatilization of Pb ion after annealing; therefore, the lattice parameter of film was reduced on an average 0.0115 ${\AA}$ by the the Pb ion.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.11 no.6
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• pp.246-251
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• 2001

The $[(Pb_{1-x}$La_{2x/3})TiO_3$, X=0.2] powder was synthesized by the hydrothermal method, and their sintering and dielectric properties according to Mn additive were examined. The relative density of sintered PLT specimen at $1150^{\circ}C$ for 5 hrs with Mn 0.02 mol% additive was 96.7%. The dielectric properties of sintered PLT specimen were changed by content of Mn and increacement of sintering temperature. Dissipation factor was improved by increasing of measuring temperature. Curie temperature of sintered PLT specimens was decreased with increasing of Mn additive.