• Korean Chemical Engineering Research
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• v.53 no.1
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• pp.103-110
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• 2015

In this work, the performance of various promoters was investigated used in $CO_2$ separation from the gases emitted from steel-making process using gas hydrate technology. The studied promoters are tetrahydrofuran (THF), propylene oxide and 1,4-dioxane, which are all expected to form a structure II hydrate, and the target gases include $CO_2/N_2$ mixed gases ($CO_2/N_2$ = 20/80 and 40/60) and Blast Furnace Gas (BFG). The phase equilibrium points were measured when each promoter was added with various concentrations. For fast acquisition of abundant data, the "continuous" Quartz crystal microbalance (QCM) method was employed. In addition, the crystal structure of each gas hydrate was analyzed by Powder X-ray diffraction (PXRD).

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.276-283
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• 1997

A dry impregnation method was used for preparing pellet type Pt/$SnO_2$ gas sensor. The crystal structure, direction of the crystal, crystal size and microstructure between the catalyst and the support ($SnO_2$) were characterized with electron diffraction analysis, transmission electron microscopy, scanning electron microscopy. The characterization indicates that when Pt/$SnO_2$ sample is calcined at $400^{\circ}C$, the Cl content associated with the Pt phase diminishes and the part of Pt is moved into $SnO_2$ support. This results in the enhancement of gas sensitivity. After the reactor with a Pt/$SnO_2$ sample was run with a flow rate of 30 sccm (a mixture of 0.5% $H_2$ in $_N2$) for a while, the resistance of $SnO_2$ was saturated, but the $SnO_2$ kept absorbing $H_2$ gas. This indicates that the surface state was saturated. For the 14 ppm $H_2$ gas, the sensitivity of Pt/$SnO_2$ devices was about 81% at an operating temperature of $300^{\circ}C$.

• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.204-211
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• 2005

The structure of nitrogen adsorption complex of fully dehydrated $Cd^{2+}$ ion exchanged zeolite-X, $|Cd_{46}(N)_{18}|[Si_{100}Al_{92}O_{384}]$, was determined in the cubic space group $Fd\overline{3}$ at 21(1) $^{\circ}C$ [a = 24.863(4) ] by single crystal X-ray diffraction analysis. The crystal was prepared by ion exchange in a flowing steam of 0.05 M aqueous solution $Cd(NO_3)_2$ : $Cd(O_2CCH_3)_2$ = 1:1 for five days, followed by dehydration at $500^{\circ}C$ and $2{\times}10^{-6}$ Tor. for two days, and exposured to 100 Tor. zeolitically dry nitrogen gas at 21(1) $^{\circ}C$. The structure was determined in atmosphere, and was refined within $F_0$ > $4{\sigma}(F_0)$ using reflection for which the final error can appear in indices $R_1$ = 0.097 and $wR_2$ = 0.150. In this structure, $Cd^{2+}$ ions occupied four crystallographic sites. Nine $Cd^{2+}$ ions filled the octahedral site I at the centers of hexagonal prisms (Cd-O = 2.452(16) ${\AA}$). Eight $Cd^{2+}$ ions filled site I' (Cd-O = 2.324(19) ${\AA}$). The remaining 29 $Cd^{2+}$ ions are found at two nonequivalent sites II (in the supercages) with occupancy of 11 and 18 ions. Each of these $Cd^{2+}$ ions coordinated to three framework oxygens, either at 2.159(15) or 2.147(14) ${\AA}$, respectively. Eighteen nitrogen molecules were adsorbed per unit cell and three per supercage.

• Proceedings of the KIEE Conference
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• 1997.07d
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• pp.1304-1307
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• 1997

A hydrogen gas sensor utilizing Pt/$SnO_2$ system was fabricated by the pressed pellet method. The crystal structure, direction of the crystal, crystal size and microstructure between the catalyst and the support ($SnO_2$) were characterized with Electron Diffraction Analysis, Transmission Electron Microscopy, Scanning Electron Microscopy. After the reactor with a Pt/$SnO_2$ sample was run with a flow rate of 30sccm (a mixture of $0.5%H_2$ in $N_2$) for a while, the resistance of $SnO_2$ was saturated, but the $SnO_2$ kept absorbing $H_2$ gas. $H_2$ gas sensing properties of Pt/$SnO_2$ were investigated at several temperatures. As a result, it was observed that Pt/$SnO_2$ has high sensitivity at $300^{\circ}C$ and $400^{\circ}C$.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.809-816
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• 1995

Ti1-xAlxN films were successfully deposited on high speed steel and silicon wafer by plasma-assisted chemical vapor deposition using a TiCl4/AlCl3/N2/Ar/H2 gas mixture. Plasma process enabled N2 gas to nitride AlCl3, which is not possible in sense of thermodynamics. XPS analyses revealed that the deposited layer contained Al-N bond as well as Ti-N bond. Ti1-xAlxN films were polycrystalline and had single phase, B1-NaCl structure of TiN. Interplanar distance, d200, of (200) crystal plane of Ti1-xAlxN was, however, decreased with Al content, x. Al incorporation into TiN caused the grain size to be finer and changed strong (200) preferred orientation of TiN to random oriented microstructure. Those microstructural changes with Al addition resulted in the increase of micro-hardness of Ti1-xAlxN film up to 2800Kg/$\textrm{mm}^2$ compared with 1400Kg/$\textrm{mm}^2$ of TiN.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.4
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• pp.145-152
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• 2015

In this work, we were investigated the effect of the additive gases on the relationship between bonding structure and mechanical properties of the deposited films when the DLC films were deposited on Si-wafer by the rf-PECVD method with the addition of small amounts of carbon dioxide and nitrogen to the mixture gas of methane and hydrogen. The deposition rate of the films increased as the rf-power increased, while it decreased with increasing the amount of additive gases. Also, as the carbon dioxide gas increased, the hydrogen content in the films decreased but the $sp^3/sp^2$ ratio of the films increased. In case of nitrogen gas, the hydrogen content decreased, however the $sp^3/sp^2$ ratio and nitrogen gas flow rate did not show a specific tendency.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.122-123
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• 2006

Tin oxide nanoparticles (n-SnO and $n-SnO_2$) were synthesized by the inert gas condensation (IGC) method under dynamic gas flow of oxygen and argon at various conditions. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) method were used to analysis the size, shape and crystal structure of the produced powders. The synthesized particles were mostly amorphous and their size increased with increasing the partial pressure of oxygen in the processing chamber. The particles also became broader in size when higher oxygen pressures were applied. Low temperature annealing at $320^{\circ}C$ in air resulted to crystallization of the amorphous n-SnO particles to $SnO_2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.213-213
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• 2009

Titanium dioxide ($TiO_2$) thin films were prepared on glass substrates by ion-assisted electron-beam evaporation with 200nm thickness and subsequently crystallized by rapid thermal annealing at the rage of $200{\sim}700^{\circ}C$ in flowing $N_2$ gas. The crystal structure of the films were examined by X-ray diffractometer. As-deposited $TiO_2$ films were amorphous. After annealing, anatase and rutile phase of $TiO_2$ films were observed together.

• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.75-78
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• 2017

The $CO_2$ gas responsibility of $SnO_2$ thin films was researched with various annealing temperatures. $SnO_2$ was prepared on n-type Si substrate by RF magnetron sputtering system and annealed in a vacuum condition. The bonding structure of $SnO_2$ was changed from amorphous to crystal structure with increasing the annealing temperature, and the content of oxygen vacancy was researched the highest of the annealed at $60^{\circ}C$. The $SnO_2$ annealed at $60^{\circ}C$ had the characteristics of the highest capacitance. The special properties of $CO_2$ gas responsibility was found at the $SnO_2$ thin film annealed at $60^{\circ}C$ with amorphous structure because of the combination with the oxygen vacancies and $CO_2$ gases changed the resistivity. The amorphous structure enhanced the responsibility at the $SnO_2$ surface and the conductivity of $SnO_2$ thin film.

• Journal of the Korean institute of surface engineering
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• v.25 no.5
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• pp.223-233
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• 1992

(Ti, Al)N films were deposited on 304 stainless steel by D.C. magnetron sputtering using Al target and Ti plate. The properties of (Ti, Al)N films such as composition, microhardness, grain size, crystal structure were investigated. The chemical composition of (Ti, Al)N films was similar to the sputter area ratio of titanium to aluminum target by means of EDS and AES survey. The higher bias voltage to substrate and the smaller input of N2 gas showedthe increased microhardness and the finer grain size of the films. The results obtained from this study show, it is belived, that the (Ti, Al)N film by D.C.magne-tron sputtering is promising in the wear resistance use.