• Journal of the Korean Ceramic Society
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• v.48 no.2
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• pp.134-140
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• 2011

To study the effect of color development of Ni-doped willemite blue pigments, five batches of compositions were prepared and fired at $1350^{\circ}C$/hold for 1 h. When Ni was substituted for ZnO by 0.03 mole the optimum result were obtained. Then they were fired at $1300^{\circ}C$ and held for 1, 2, 4 and 6 h respectively for the purpose sake. XRD, Raman spectroscopy, FT-IR, UV-vis were used to analyze the results of experiment. The substitution of 0.03mole Ni for Zn was most optimum and which produced good willemite at the temperature of $1300^{\circ}C$, holding for 6 h. In ceramic arts, cobalt has been used for blue coloring, in most cases, despite of its high cost. If the low cost Ni-doped willemite blue pigments supplies for them with stable and multiple shades of blue pigment, using NiO at high temperature, it would provide various blues for ceramic wares.

• Journal of the Korean institute of surface engineering
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• v.40 no.3
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• pp.107-112
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• 2007

Aluminum doped zinc oxide (AZO) films were deposited on non-alkali glass substrate by DC magnetron sputtering with 3 types of AZO targets (doped with 1.0 wt%, 2.0 wt%, 3.0 wt% $Al_2O_3$). Electrical, optical properties and microstructure of AZO films have been investigated by Hall effect measurements, UV/VIS/NIR spectrophotometer, and XRD, respectively. Crystallinity of AZO films increased with increasing substrate temperature ($T_s$) and doping ratio of Al. Resistivity and optical transmittance in visible light were $8.8{\times}10^{-4}{\Omega}cm$ and above 85%, respectively, for the AZO film deposited using AZO target (doped with 3.0 wt% $Al_2O_3$) at $T_s$ of $300^{\circ}C$. On the other hand, transmittance of AZO films in near-infrared region decreased with increasing $T_s$ and doping ratio of Al, which could be attributed to the increase of carrier density.

• Carbon letters
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• v.11 no.4
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• pp.332-335
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• 2010

The photodegradation of the model compounds Quinol, an aromatic organic compound and Acid blue FFS, an acid dye of chemical class Triphenylmethane was studied by using illumination with UV lamp of light intensity 250W. $TiO_2$ and $TiO_2$ doped with Boron and Nitrogen was used as catalyst. The sol-gel method was followed with titanium isopropoxide as precursor and doping was done using Boron and Nitrogen. In photocatalytic degradation, $TiO_2$ and doped $TiO_2$ dosage, UV illumination time and initial concentration of the compounds were changed and examined in order to determine the optimal experimental conditions. Operational time was optimized for 360 min. The optimum dosage of $TiO_2$ and BN doped $TiO_2$ was obtained to be 2 $mgL^{-1}$ and 2.5 $mgL^{-1}$ respectively. Maximum degradation % for quinol and Blue FFS acid dye was 78 and 95 respectively, at the optimum dosage of BN-doped $TiO_2$ catalyst. It was 10 and 4% higher than when undoped $TiO_2$ catalyst was used.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1294-1300
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• 1998

Yttria-stabilized zirconia ceramics with irregular grain shapes and curved grain boundaries was prepared by ceria doping. The amount of ceria doped into zirconia compacts by a dipping method were at range of 2 to 20 mol% Irregular grain shapes and curved grain boundaries were formed only inspecimens doped with more than 8mol% cerial. Ceria-doped specimens showed large grain size and low sintered density compared with pure yttria-stabilized zirconia which was due to the increase in the contents of stabilizer and cubic phase. The amount of doped ceria was larger on the surface than the inside regions and therefore mi-crostructure and phase on the surface were different from those in the inside regions. Transgranular frac-ture mode was observed ion ceria doped specimens due to irregular large grain sizes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.312-316
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• 1999

I-V characteristics of Praseodymium-based ZnO varistor doped with $Nd_2O_3$ in the range 0.0-2.0mol% sintered at 130$0^{\circ}C$ and 135$0^{\circ}C$ were investigated. In the all sides, ZnO varistors sintered at $1300^{\circ}C$ exhibited much better varistor characteristics than that at 135$0^{\circ}C$. All ZnO varistors doped with $Nd_2O_3$ sintered at $1300^{\circ}C$ exhibited good varistor characteristics but particularly ZnO varistor doped with l.Omol% $Nd_2O_3$ exhibited the best characteristics, which the nonlinear is 65.2 and the leakage current is 4.5pA. It is estimated that ZnO varistor doped with l.Omol% $Nd_2O_3$ will begin to be sufficiently used as basic composition to fabricate a good varistor.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.1993-1997
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• 2012

Mg-doped ZnO one-dimensional (1D) nanostrutures were synthesized by using a thermal evaporation technique. The morphology, crystal structure, and sensing properties of the Mg-doped ZnO nanostructures functionalized with Pt to CO gas at $100^{\circ}C$ were examined. The diameters of the 1D nanostructures ranged from 80 to 120 nm and that the lengths were up to a few tens of micrometers. The gas sensors fabricated from multiple networked Mg-doped ZnO nanowires functionalized with Pt showed enhanced electrical response to CO gas. The responses of the nanowires were improved by approximately 70, 69, 111, and 81 times at CO concentrations of 10, 25, 50, and 100 ppm, respectively. Both the response and recovery times of the nanowire sensor for CO gas sensing were not nearly changed by Pt functionalization. It also appeared that the Mg doping concentration did not influence the sensing properties of ZnO nanowires as strongly as Pt-functionalization. In addition, the mechanism for the enhancement in the CO gas sensing properties of Mg-doped ZnO nanowires by Pt functionalization is discussed.

• Textile Coloration and Finishing
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• v.32 no.3
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• pp.158-166
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• 2020

Self-cleaning fabric is a fabric having a function of decotamination via photodecomposition of photocatalyst or wash-off of contaminants on the superhydrophobic surface. TiO₂ is the main photocatalyst for this purpose, but it only functions under UV light which is only a little portion of sunlight, compared to visible light. In this regard, this study aims to investigate Fe-doped TiO₂ for improved photodecomposition from visible light sensitization to apply self-cleaning finishing of PET fabrics. Moreover, the Fe-doped TiO₂ treated PET fabric was further treated with hexadecyltrimethoxysilane to provide superhydrophobicity on the PET fabrics. As a result of this dual treatment, the prepared fabric exhibited excellent photodecomposition of methylene blue with 96.96% in 12h under sunlight and superhydrophobicity with water contact angle of 166.5° and roll-off angle of 7°. This suggested that the excellent self-cleaning functions can be privided to PET fabric via Fe-doped TiO₂ and hexadecyltrimethoxysilane treatment.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.226-226
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• 2010

Microstructure, magnetic and transport properties of as-deposited electron-doped $La_{1-x}Ce_xMnO_3$ and hole-doped $La_{1-x}Ce_xMnO_3$ films prepared by pulse laser deposition, with x = 0.1 and 0.3, have been investigated. The microstructural analysis reveals that the $La_{1-x}Ce_xMnO_3$ films have a column-like microstructure and a strip-domain phase with a periodic spacing of about 3c, which were not found for the $La_{1-x}Ce_xMnO_3$ ones. At the same time, the experimental results manifest that there is no fundamental difference in the magnetic and the transport properties between electron- and hole-doped manganite films, except the appearance of ferromagnetic response in the low-doped $La_{0.9}Ce_{0.1}MnO_3$ film at temperatures above the Curie point. The observed magnetic behavior, typical for the Griffiths-like phase, for this film is explained by the percolation mechanism of the ferromagnetic transition and by the presence of strip-domain phase which stimulates the magnetic phase separation.

• Korean Journal of Materials Research
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• v.31 no.8
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• pp.471-479
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• 2021

The electrochemical reaction between lead borate glass frit doped with Sn metal filler and Ni-Cr wire of a J-type resistor during a term of Joule heating is investigated. The fusing behavior in which the Ni-Cr wire is melted is not observed for the control group but measured for the Sn-doped specimen under 30 V and 500 mA. The Sn-doped lead borate glass frit shows a fusing property compared with other metal-doped specimens. Meanwhile, the redox reaction significantly contributes to the fusing behavior due to the release of free electrons of the metal toward the glass. The electrons derived from the glass, which used Joule heat to reach the melting point of Ni-Cr wire, increase with increasing corrosion rate at interface of metal/glass. Finally, the confidence interval is 95 ± 1.95₉ %, and the adjusted regression coefficient, R in the optimal linear graph, is 0.93, reflecting 93% of the data and providing great potential for fusible resistor applications.

• Korean Journal of Metals and Materials
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• v.47 no.12
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• pp.860-865
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• 2009

The effect of Co additive on the electrical properties of Fe-Si alloys prepared by a RF inductive furnace was investigated. The electrical conductivity and Seebeck coefficient were measured as a function of the temperature under an Ar atmosphere to evaluate their applicability to thermoelectric energy conversion. The electrical conductivity of the specimens increased as the temperature increased, showing typical semiconducting behavior. The electrical conductivity of Co-doped specimens was higher than that of undoped specimens and increased slightly as the amount of Co additive increased. This is most likely due to the difference in the carrier concentration and the amount of residual metallic phase ${\varepsilon}$-FeSi (The ${\varepsilon}$-FeSi was detected in spite of an annealing treatment of 100 h at $830^{\circ}C$). Additionally, metallic conduction increased slightly as the amount of Co additive increased. On the other hand, Co-doped specimens showed a lower Seebeck coefficient due to the metallic phase. The power factor of Co-doped specimens was higher than that of undoped specimens. This would be affected more by the electrical conductivity compared to the Seebeck coefficient.