• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.341-344
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• 2004

The superconducting properties of $YBa_2Cu_3O_x$ with different content impurities of PbO and $BaPbO_3$ were studied. When the PbO was used as an additive in $YBa_2Cu_3O_x$, although the melting point could be reduced, the superconductivity became poor. From the XRD pattern of the sintered mixture of $YBa_2Cu_3O_x$ and PbO it was known that there is a reaction between $YBa_2Cu_3O_x$ and PbO, and the product is $BaPbO_3$. In the process of the reaction the superconducting phase of $YBa_2Cu_3O_x$ was decreased and $BaPbO_3$ would be the main phase in the sample. Therefore, $BaPbO_3$ was chosen as the impurity additive for the comparative study. The single phase of $BaPbO_3$ was synthesized by the simple way from both mixtures of $BaCO_3$ and PbO, $BaCO_3$ and $PbO_2$. Different contents of $BaPbO_3$ (10%, 20%, 30%) were added in the $YBa_2Cu_3O_x$. By the Phase analysis in the XRD patterns it was proved that there was no reaction between $YBa_2Cu_3O_x$ and $BaPbO_3$. When $BaPbO_3$ was used as impurity in $YBa_2Cu_3O_x$ the superconductivity was much better than PbO as an impurity additive in $YBa_2Cu_3O_x$.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.929-931
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• 1999

BSCCO thin films have been fabricated by co-deposition at an ultralow growth rate using ion beam sputtering(IBS) method. Bi 2212 phase appeared in the temperature range of 750 and $795^{\circ}C$ and single phase of Bi 2201 existed in the lower region than $785^{\circ}C$. Whereas, ozone gas pressure dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with $T_c$(onset) of about 90 K and $T_c$(zero) of about 45 K is obtained. Only a small amount of CuO in some films was observed as impurity, and no impurity phase such as $CaCuO_2$ was observed in all of the obtained films.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.222-225
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• 2000

BSCCO thin films have been fabricated by co-deposition at an ultralow growth rate using ion beam sputtering(IBS) method. Bi 2212 phase appeared in the temperature range of 750 and $795^{\circ}C$ and single phase of Bi 2201 existed in the lower region than $785^{\circ}C$. Whereas, $Po_3$ dependance on structural formation was scarcely observed regardless of the pressure variation. And high quality of c-axis oriented Bi 2212 thin film with $T_c$ (onset) of about 90 K and $T_c$(zero) of about 45 K is obtained. Only a smd amount of CuO in some films was observed as impurity, and no impurity phase such as $CaCuO_2$ was observed in d of the obtained films.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.5-8
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• 1989

Conventional ceramic method has been used to prepare the green phase, $Y_2BaCuO_5$, commonly observed in 90-K superconductor $YBa_2Cu_3O_P{7-{\delta}}$as an impurity phase. The powder X-ray diffraction analysis indicates that $Y_2BaCuO_5$ has an orthorhombic symmetry with lattice parameter of a = 12.2 $\AA$, b = 5.61 $\AA$, and c = 7.14 $\AA.$ The average g-value 2.13 observed in ESR spectrum is attributable to Cu2+ stabilized in $C_{4v}$ field. From the magnetic susceptibility ($\mu$eff = 2.29 BM) and the ESR measurements, it is confirmed that Cu(II) $3d^9$ electrons in $Y_2BaCuO_5$ are localized and can be characterized by Curie-Weiss behavior. Optical reflectance spectrum shows a broad absorption peak around 680 nm due to dxy ${\rightarrow}$ $dx^2-y^2$ eletronic transition.

• Progress in Superconductivity
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• v.1 no.2
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• pp.135-140
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• 2000

Distribution of Pr ions between Y- and Ba-site of the $Y(Ba_{1-Xn}Pr_{Xn})_2Cu_3O_y$ ($0{\leq}Xn{\leq}{0.3}$, Xn : nominal composition) material prepared by the solid state reaction method was studied. Although the samples have narrow superconducting transition, tiny peaks of $Y_2BaCuO_5$ impurity phase are included in the x-ray diffraction patterns suggesting that some of the Pr ions are entered into the Y-site. The distribution of Pr ions between Y- and Ba-site was determined by measuring the mass fraction of YBCO and $Y_2BaCuO_5$ phase for each sample through the Rietveld analysis of the x-ray diffraction data. About 60 % of Pr ions occupy the Y-site regardless of the Pr content. Various superconducting parameters such as the oxygen content and the hole concentration etc. are compared before and after the impurity correction.

• Journal of the Speleological Society of Korea
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• no.78
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• pp.17-22
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• 2007

The melting temperature and critical temperature (Tc) of $YBa_2Cu_3O_x$ with deferent content impurities of PbO and $BaPbO_3$ were studied. When the PbO was used as addition in $YBa_2Cu_3O_x$, although the melting point could be reduced, the superconductivity (the transition wide, ${\Delta}T_c$) became poor. From the XRD pattern of the sintered mixture of $YBa_2Cu_3O_x$ and PbO it was known that there is a reaction between $YBa_2Cu_3O_x$ and PbO, and the product is $BaPbO_3$. In the process of the reaction the superconducting phase of $YBa_2Cu_3O_x$ was decreased and in the sample $BaPbO_3$ became the main phase. Therefore the superconductivity was reduced. $BaPbO_3$ was chosen as the impurity for the comparative study. The single phase $BaPbO_3$ was synthesized by the simple way from both mixtures of $BaCO_3$ and PbO, $BaCO_3$ and $PbO_2$. Deferent contents of $BaPbO_3$ (10%, 20%, 30%) were added in the $YBa_2Cu_3O_x$. By the phase analysis in the XRD patterns it was proved that there were not reactions between $YBa_2Cu_3O_x$ and $BaPbO_3$. When $BaPbO_3$ was used as impurity in $YBa_2Cu_3O_x$ the superconductivity was much better than PbO as impurity in $YBa_2Cu_3O_x$. But the melting point of $YBa_2Cu_3O_x$ with $BaPbO_3$ could not be found when the temperature was lower than $1000^{\circ}C$ in the DTA measurement.

• KSBB Journal
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• v.15 no.5
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• pp.537-540
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• 2000

In developing a HPLC purification process, it was hoped that a single chromatographic system would be sufficient to abtain pure paclitaxel in high yield. However, no such system was found, due in part to the complex taxoid profile of crude paclitaxel and to the rigorous nature of the product specification. A two step HPLC purification was adopted using reverse-phase separation on C(sub)18 as a first step, and normal-phase separation on silica as the final polishing step. Impurity profiles were established and maintained for paclitaxel, which identified and quantified each impurity observed in purified paclitaxel from these two steps, all impurities at or above 0.1% were identified. Results provide information for improving the quality control of paclitaxel production.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05a
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• pp.57-59
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• 2004

The melting temperature and critical temperature (Tc) of YBa$_2$Cu$_3$Ox with deferent content impurities of PbO and BaPbO$_3$ were studied. When the PbO was used as addition in YBa$_2$Cu$_3$Ox, although the melting point could be reduced, the superconductivity (the transition wide, ΔTc) became poor. From the XRD pattern of the sintered mixture of YBa$_2$Cu$_3$Ox and PbO it was known that there is a reaction between YBa$_2$Cu$_3$Ox and PbO, and the product is BaPbO$_3$. In the process of the reaction the superconducting phase of YBa$_2$Cu$_3$Ox was decreased and in the sample BaPbO$_3$became the main phase. Therefore the superconductivity was reduced. BaPbO$_3$was chosen as the impurity for the comparative study. The single phase BaPbO$_3$was synthesized by the simple way from both mixtures of BaPbO$_3$and PbO, BaPbO$_3$and PbO$_2$. Deferent contents of BaPbO$_3$(10%, 20%, 30%) were added in the YBa$_2$Cu$_3$Ox. By the phase analysis in the XRD patterns it was proved that there were not reactions between YBa$_2$Cu$_3$Ox and BaPbO$_3$. When BaPbO$_3$was used as impurity in YBa$_2$Cu$_3$Ox the superconductivity was much better than PbO as impurity in YBa$_2$Cu$_3$Ox But the melting point of YBa$_2$Cu$_3$Ox with BaPbO$_3$could not be found when the temperature was lower than 1000 $^{\circ}C$ in the DTA measurement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.543-546
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• 2004

The melting temperature and critical temperature(Tc) of $YBa_2Cu_3O_x$ with deferent content impurities of PbO and $BaPbO_3$ were studied. When the PbO was used as addition in $YBa_2Cu_3O_x$, although the melting point could be reduced, the superconductivity(the transition width, ${\Delta}T_c$) became poor. From the XRD pattern of the sintered mixture of $YBa_2Cu_3O_x$ and PbO it was known that there is a reaction between $YBa_2Cu_3O_x$ and PbO, and the product is $BaPbO_3$. In the process of the reaction the superconducting phase of $YBa_2Cu_3O_x$ was decreased and in the sample $BaPbO_3$ became the main phase. Therefore the superconductivity was reduced. $BaPbO_3$ was chosen as the impurity for the comparative study. The single phase BaPbO3 was synthesized by the simple way from both mixtures of $BaPbO_3$ and PbO, $BaPbO_3\;and\;PbO_2$. Deferent contents of $BaPbO_3$(10%, 20%, 30%) were added in the $YBa_2Cu_3O_x$. By the phase analysis in the XRD patterns it was proved that there werenot reactions between $YBa_2Cu_3O_x$ and $BaPbO_3$. When $BaPbO_3$ was used as impurity in $YBa_2Cu_3O_x$ the superconductivity was much better than PbO as impurity in $YBa_2Cu_3O_x$. But the melting point of $YBa_2Cu_3O_x$ with $BaPbO_3$ could not be found when the temperature was lower than $1000^{\circ}C$ in the DTA measurement.

• Progress in Superconductivity
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• v.6 no.1
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• pp.37-40
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• 2004

We investigated the effects of impurity doping on the electrical transport and magnetic properties of TEX>$(Ru, Sn)(Sr, La)<_2$$EuCeCu_2$$O_{z}$ samples. We found that Sn substitution fur Ru causes a significant decrease of the volume fraction of ferromagnetic phase, as well as a decrease of the temperature where the ferromagnetic component is observed. La substitution for Sr leads to an increase of the magnetic ordering temperature with a moderate change of ferromagnetic component. The experimental results are discussed in conjunction with the structural data, transport properties and a possible change of oxygen content.