• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.286-288
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• 2014

This study deals with the catalyst free radio frequency plasma assisted polymerization of ethylene glycol using nitrogen as reactive gas to modify the surface chemistry and morphology. The deposited film was characterized through various analysis techniques i.e. surface profilometry, Forier transform infrared spectroscopy, water contact angle and UV-visible spectroscopy to analyze film thickness, chemical structure, surface energy and optical properties respectively. The surface topography was analyzed by Atomic force microscopy. It was observed that the ethylene oxide behaviour and optical transmittance of the film were reduced with the introduction of nitrogen gas due to higher fragmentation of monomer. However the hydrophilic behavior of the film improved due to formation of new water loving functional groups suitable for biomedical applications.

• Journal of the Korean Ceramic Society
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• v.33 no.9
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• pp.961-968
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• 1996

The aluminum nitride was synthesized by the self-propagating high-temperature synthesis(SHS). The synthe-sis was used aluminum powder mixed with AlN powder as reactant and the control factors affected to synthesis were considered compact density pressure of reaction gas AlN diluent content and aluminum powder size. The SHS reaction conducted with a reactant containing 50% AlN diluent under 0.8MPa nitrogen gas pressure yielded a complete conversion of aluminum powder to AlN powders. The size and purity of AlN produced were found to be comparable with that of AlN produced by the carbothermal nitrogen method.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.384-384
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• 2010

Zirconium oxynitride films were obtained by r.f. reactive magnetron sputtering of a zirconium target with nitrogen flow rate ranging from 0 to 60 sccm. The phases present in the films were determined by X-ray diffraction (XRD). Measurements of the oxidation state $ZrON_x$ films were investigated by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Thickness of these samples was estimated by spectroscopic ellipsometry (SE) and scanning electron microscopy (SEM). We found that the surface morphology of $ZrON_x$ films measured by atomic force microscopy (AFM) was also depended on the nitrogen gas flow.

• Bulletin of the Korean Chemical Society
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• v.9 no.4
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• pp.244-248
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• 1988

Multilayer adsorption isotherms of nitrogen on hexagonal boron nitride, ${\gamma}$-alumina, and silica-gel powders are determined at the liquid nitrogen temperature using a gravimetric adsorption apparatus. The volume (V) of the adsorbed gas are plotted against the statistical thickness(t) of the adsorbed layer, and the t-method area are calculated from the slope of these V-t plots to compare with the BET area. A number of universal adsorption isotherms and the Frenkel-Halsey-Hill equation are used one after another in calculating the statistical thickness. The appropriateness of the FHH equation as an universal adsorption isotherm is discussed finally.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.14-15
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• 2006

In this study, a new laval type nozzle was designed and manufactured. Using this nozzle tin powder was produced in close coupled system by using nitrogen gas at different operating conditions. The results showed that the increasing the gas pressure up to 1.47 MPa reduced the mean powder size down to 11.39 microns with a gas/melt mass flow rate ratio of 2.0. Powders are spherical in shape and have smooth surfaces.

• Korean Journal of Materials Research
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• v.24 no.1
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• pp.19-24
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• 2014

We report the nitrogen monoxide (NO) gas sensing properties of p-type CuO-nanorod-based gas sensors. We synthesized the p-type CuO nanorods with breadth of about 30 nm and length of about 330 nm by a hydrothermal method using an as-deposited CuO seed layer prepared on a $Si/SiO_2$ substrate by the sputtering method. We fabricated polycrystalline CuO nanorod arrays at $80^{\circ}C$ under the hydrothermal condition of 1:1 morality ratio between copper nitrate trihydrate [$Cu(NO_2)_2{\cdot}3H_2O$] and hexamethylenetetramine ($C_6H_{12}N_4$). Structural characterizations revealed that we prepared the pure CuO nanorod array of a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the gas sensing measurements that the p-type CuO nanorod gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as $200^{\circ}C$. We also found that these CuO nanorod gas sensors showed reversible and reliable electrical response to NO gas at a range of operating temperatures. These results would indicate some potential applications of the p-type semiconductor CuO nanorods as promising sensing materials for gas sensors, including various types of p-n junction gas sensors.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1010-1014
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• 2004

High quality GaN layer and $In_xGa_{1-x}N$ alloy were obtained on (0001)sapphire substrate using ammonia$(NH_3)$ and dimethylhydrazine$(DMH_y)$ as a nitrogen source by gas source molecular hem epitaxy(GSMBE) respectively. As a result, RHEED is used to investigate the relaxation processes which take place during the growth of GaN and $In_xGa_{1-x}N$. The full Width at half maximum of the x-ray diffraction(FWHM) rocking curve measured from Plane of GaN has exhibitted as narrow as 8 arcmin. Photoluminescence measurement of GaN and $In_xGa_{1-x}N$ were investigated at room temperature, where the intensity of the band edge emission is much stronger than that of deep level emission. In content of $In_xGa_{1-x}N$ epitaxial layer according to growth condition was investigated.

• Electrical & Electronic Materials
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• v.7 no.1
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• pp.25-31
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• 1994

Properties of oxynitride films reoxidized by $N_2{O}$ gas after thermal oxidation and $N_2{O}$ oxide films directly oxidized by using $N_2{O}$ gas on the bare silicon wafer have been studied. From the AES analysis, nitrogen pile-up at the interface of Si/oxynitride and Si/$N_2{O}$ oxide has observed. $N_2{O}$ oxide and oxynitride films have the self-limited characteristics. Therefore, it will be possible to obtain ultra-thin films. Nitrogen pile-up at the interfaces of Si/oxynitride and Si/$N_2{O}$ oxide strengthens film structure and improves dielectric reliability. Although fixed charge densities and interface trap densities of N20 oxide and oxynitride films have somewhat higher than those of thermal $SiO_2{O}$, $N_2{O}$ oxide and oxynitride films showed improved I-V characteristics and constant current stress.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.416-420
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• 2003

The analytical method of antispasmodic agent tiropramide {$(\pm)\alpha$-(benzoylamino)-4-[2-(diethylamino)ethoxy]-N,N-dipropylbenzenepropanamide hydrochloride} was developed by gas chromatography/nitrogen-phosphorus detector (GC/NPD) in human plasma. Two kinds of tiropramide tablets were orally administered to volunteers by Latin square crossover design, and blood was withdrawn as designed schedule. The plasma of 1 mL was loaded on Sep-pak $C_{18}$ cartridge and eluted with methanol after washing with 30% methanol. The residue dissolved in 100 $\mu$L of methanol after evaporation was analyzed by GC/NPD. Precision (CV%) of intra-day was located within 2.6% and accuracy was less than 9.7%. Inter-day precision was below 8.7% and accuracy was relatively good as less than 14%. Plasma samples obtained from human volunteers were analyzed for the determination of tiropramide concentration by using this method. The method was sensitive, rapid and suitable enough to be applied for pharmacokinetic and bioequivalence studies of tiropramide in human volunteers.

• Korean Journal of Metals and Materials
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• v.46 no.11
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• pp.708-712
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• 2008

The influence of high temperature gas nitriding (HTGN) in STS347 and STS310S steels was experimentally investigated. The HTGN was carried out at $1,050^{\circ}C{\sim}1,150^{\circ}C$ for 10 hrs in a gaseous atmosphere containing $1kg/mm^2$ of nitrogen. After HTGN, fine precipitates of $Cr_2N$ and NbN appeared in austenite on the surface of STS 347, while nitrogen pearlite, which was layeredof $Cr_2N$ and austenite alternatively, appeared in austenite on the surface of STS 310S. The surface hardness of HTGN-treated, STS 347 and STS 310S specimens was 250~360 Hv and 270~400 Hv, respectively, depending on the temperature of HTGN. The nitrogen content was analyzed 1.4 wt% and 1.6 wt% at the surface layer of STS 347 and STS 310S steels, respectively. In addition, an improvement in the corrosion resistance of HTGN treated specimens was observed.