• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.592-599
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• 2000

The fine particles of binary ceramic composite of titania-partially-stabilized zirconia(TPSZ) were synthesized by ultrasonic spray pyrolysis at the various temperatures, compositions and concentrations and the effects of process factors for synthesis on the characteristics of fine particles were discussed. The starting salt solutions were prepared to have the ionic concentrations of 0.025~0.1 M aqueous solutions. The fine particles were prepared to have the compositions of 90~97.5 wt% of $ZrO_2$ and 2.5~10 wt% of $TiO_2$. The temperatures for particle synthesis were regulated to be 400~550$^{\circ}C$ as a drying zone, 800~1100$^{\circ}C$ as a pyrolysis zone. The produced fine particles were collected by a wet process and analyzed to investigate characteristic properties after being dried. The compositions of ceramic fine particles were determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy(ICP-AES) technique and phases, morphologies and particle sizes of those were investigated by Raman Spectroscopy, X-ray diffraction(XRD), Scanning Electron Microscopy(SEM), Transmission Electron Microscopy(TEM) and Particle Size Analyzer(PSA) techniques.

• Resources Recycling
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• v.22 no.5
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• pp.50-55
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• 2013

The recovery of copper from spent photovoltaic ribbon was conducted using thermal treatment method at the range of temperature of $300^{\circ}C$ to $600^{\circ}C$ under inert atmosphere. The coating layer consisted of lead of 68.99 wt.% and tin of 31.21 wt.% was melted down at elevated temperatures and was collected on the bottom of crucible. The chemical composition of copper ribbon after thermal treatment was analyzed by ICP-MS (Inductively coupled plasma mass spectrometry) and the purity of copper was found to be obtained up to about 96 wt.% regardless of temperatures. The cross-sectional area of the specimen was also examined by SEM (scanning electron microscopy) and EDX (energy dispersive X-ray microscopy).

• Korean Chemical Engineering Research
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• v.46 no.1
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• pp.170-174
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• 2008

ZnS-polymer gel films were prepared with incorporating mesoporous ZnS synthesized by surfactant-assisted templating process and poly (vinylidene fluoride)-hexafluoropropylene copolymer (P(VDF-HFP)) in order to observe the variation of ionic conductivities according to the various weight ratios between ZnS and P(VDF-HFP). Ionic conductivities for each gel electrolyte were measured with increasing temperature. As a result, ionic conductivities increased with increasing the amount of ZnS and temperature. In particular, the films with 20 and 25 wt% ZnS were found that they possessed the high ionic conductivity of approximately $10^{-4}Scm^{-1}$ at room temperature. However, above 20 wt% of ZnS, the enhancement of ionic conductivity was not observed. For the characterization of ZnS and the gel electrolyte, XRD (x-ray diffractometer), DSC (differential scanning calorimetry), TGA (thermogravimetric analysis), FT-IR (fourier transform-infrared spectrometer), SEM (scanning electron microscopy) and TEM (transmission electron microscopy) were employed. Ionic conductivities were measured by a.c. impedance method.

• Elastomers and Composites
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• v.49 no.4
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• pp.330-335
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• 2014

Niobium pentoxide ($Nb_2O_5$) nanoparticles were synthesized using niobium (V) chloride and pluronic F108NF as the precursor and templating agent, respectively. The $Nb_2O_5$-graphene nanocomposites were placed in an electric furnace at $700^{\circ}C$ and calcined under Ar atmosphere for 2 h. The morphology, crystallinity, and photocatalytic degradation activity of the samples were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and UV-vis spectroscopy. The $Nb_2O_5$-graphene nanocomposites acted as a photocatalyst in the photocatalytic degradation of organic dyes under 254 nm UV light; the organic dyes used were methylene blue (MB), methyl orange (MO), rhodamine B (RhB), and brilliant green (BG). The photocatalytic degradation kinetics for the aforesaid dyes were determined in the presence of the $Nb_2O_5$-graphene nanocomposites.

• Membrane Journal
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• v.29 no.3
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• pp.183-189
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• 2019

Amphiphilic PCZ-r-PEG random copolymer assisted solvothermal process is used to prepare mesoporous $TiO_2$ microspheres generated from nanoparticles by self-assembly method. Synthesized PCZ-r-PEG is characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), gel permeation chromatography (GPC) and transmission electron microscopy (TEM). The mesoporous $TiO_2$ are prepared by PCZ-r-PEG, glucose, water in tertrahydrofuran solution at $150^{\circ}C$ for 12 h and the $TiO_2$ microspheres are calcined at $550^{\circ}C$ for 30 min to further crystallize and organic residue are removed. Morphology and crystallization phase is characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. The mesoporous $TiO_2$ crystallized in pure anatase phase with diameter of $300{\pm}20nm$.

• Proceedings of the Materials Research Society of Korea Conference
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• 1999.11a
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• pp.76-76
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• 1999

Low resistance ohmic contacts to the Si-doped InGaN(~$\times$10$^{19}$ ㎤) were obtained using the W metallization schemes. Specific contact resistance decreased with increasing annealing temperature. The lowest resistance is obtained after a nitrogen ambient annealing at 95$0^{\circ}C$ for 90s, which results in a specific contact resistance of 2.75$\times$10$^{-8}$ Ω$\textrm{cm}^2$. Interfacial reactions and surface are analyzed using x-ray diffraction, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The X-ray diffraction results show that the reactions between the W film and the InGaN produce a $\beta$-W$_2$N phase at the interface. TEM results also show that the $\beta$-W$_2$N has a rough interface, which increase contact area. It shows that the morphology of the contacts is stable up to a temperature as high as 95$0^{\circ}C$. Possible mechanisms are proposed to describe the annealing temperature dependence of the specific contact resistance.

• Bulletin of the Korean Chemical Society
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• v.33 no.2
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• pp.398-402
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• 2012

ZnSe/$SiO_2$ coaxial nanowires were synthesized by a two-step process: thermal evaporation of ZnSe powders and sputter-deposition of $SiO_2$. Two different types of nanowires are observed: thin rod-like ones with a few to a few tens of nanometers in diameter and up to a few hundred of micrometers in length and wide belt-like ones with a few micrometers in width. Room-temperature photoluminescence (PL) measurement showed that ZnSe/$SiO_2$ coaxial nanowires had an orange emission band centered at approximately 610 nm. The intensity of the orange emission from the $SiO_2$-sheathed ZnSe nanowires was enhanced significantly by annealing in a reducing atmosphere whereas it was degraded by annealing in an oxidizing atmosphere. The origins of the PL changes by annealing are discussed based on the energy-dispersive X-ray spectroscopy analysis results.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.475-479
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• 2004

$TiO_2$ thin films were grown on Si (100) substrates by atomic layer deposition using $[Ti(OPr^i )_2(dmae)_2]$ and water as precursors. The thickness, chemical composition, crystalline structure, and morphology of the deposited films were investigated by transmission electron microscopy, UV spectrometry, X-ray photoelectron pectroscopy, X-ray diffraction, and atomic force microscopy. The results show that $TiO_2$ ALD using $[Ti(OPr^i )_2(dmae)_2]$ as a precursor is self-controlled at temperatures of 100-300$^{\circ}C$. At the growth temperatures below 300$^{\circ}C$, the surface morphology of the $TiO_2$ films is smooth and uniform. The $TiO_2$ film was grown with a preferred orientation toward the [101] direction at 400$^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.33 no.8
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• pp.2694-2698
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• 2012

Materials on the scale of nanoscale have widely been used as research topics because of their interesting characteristics and aspects they bring into the field. Out of the many metal oxides, zinc oxide (ZnO) was chosen to be fabricated as nanofibers using the electrospinning method for potential uses of solar cells and sensors. After ZnO nanofibers were obtained, calcination temperature effects on the ZnO nanofibers were studied and reported here. The results of scanning electron microscopy (SEM) revealed that the aggregation of the ZnO nanofibers progressed by calcination. X-ray diffraction (XRD) study showed the hcp ZnO structure was enhanced by calcination at 873 and 1173 K. Transmission electron microscopy (TEM) confirmed the crystallinity of the calcined ZnO nanofibers. X-ray photoelectron spectroscopy (XPS) verified the thermal oxidation of Zn species by calcination in the nanofibers. These techniques have helped us deduce the facts that the diameter of ZnO increases as the calcination temperature was raised; the process of calcination affects the crystallinity of ZnO nanofibers, and the thermal oxidation of Zn species was observed as the calcination temperature was raised.

• Bulletin of the Korean Chemical Society
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• v.31 no.7
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• pp.1981-1987
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• 2010

A novel composite (Ag-CNT/$TiO_2$) of silver treated carbon nanotubes (Ag-CNT) and $TiO_2$ was synthesized via wet chemistry followed by a heat treatment. The dispersion and structure of the silver in the synthesized composites determined by X-ray diffraction (XRD), energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy(TEM). XRD patterns of the composites showed that the composites contained a mixing anatase and rutile phase. The EDX spectra showed the presence of C, O, Ti and Ag peaks. The $TiO_2$ particles were distributed uniformly in the CNT network, and silver particles were virtually fixed on the surface of the tube. The photocatalysis degraded behaviors of the Ag-CNT/$TiO_2$ composites of the methylene blue, which increased with an increase of the silver component. The Ag-CNT/$TiO_2$ composites have excellent antibacterial activities against Escherichia coli (E. Coli), Pseudomonas aeruginosa (P. Aeru) and Bacillus subtilis (B. Sub) under visible light.