• Journal of Surface Science and Engineering
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• v.22 no.3
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• pp.135-144
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• 1989

Aluminium Oxide was deposited with a C.V.D.-technique on various substrates. The effects of various treating condition such as temperature, time, heat resistance and composition of substrates were investigated in order to understand the relationship of structure, property and process. Grain size depends upon the activity of adsorption siite and coarsened with increasing temperature and time. Deposition rate decreases in order of electrolytic iron, carbon steel STS430 and STS304, since the active site for adsorption of reactant was more decreased for Cr and Ni than Fe. Oxidation resistance of alumina coated specimens improved markedely and that of stainless steel was prominent.

• Journal of Surface Science and Engineering
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• v.45 no.5
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• pp.198-205
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• 2012

The corrosion properties of anodized films on aluminium 6070 alloy in a sulfuric acid have been studied. Comparison to evaluate the anodized A6070 and pure 6070 specimen, corrosion tests in $HNO_3$ vapor environment of the 20 wt.% were performed up to 72 hours. Characteristics of film formation and surface morphology were examined by optical microscopy, FE-SEM, and EDS. The oxide film anodized in the sulfuric acid solution contained 5 to 10 wt.% of sulfur. In the initial stages of corrosion, anodized specimens exhibited corrosion resistance than the pure specimen. However, the corrosion conditions in 24 hours, corrosion was far more anodized specimen than pure specimen. Therefore, anodized films contained sulfur, nitric acid vapor in the environment is thought to stimulate corrosion.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.329-329
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• 2012

알루미늄 합금은 기존에는 경량소재로써 각광을 받아왔지만, 최근에는 다양한 전자 및 기계 부품에서 방열이 크게 대두 됨에 따라 방열 소재로써의 관심이 증가하고 있다. 알루미늄 합금의 고유한 표면처리법인 양극산화에의해 생성되는 산화층의 열전도도에 대한 연구를 실시하였다. 또한, 이들 산화층은 실리이라는 후처리에 의해서 기공구조의 변화가 일어나는데, 이 실링 처리가 열전도도에 미치는 영향에 대해서 확인해 보았다. 양극 산화피막의 미세 기공층이 비어있는 경우에 비해서 실링에 의해서 기공이 산화물 및 수산화물로 채워진 경우 열전도도가 증가하였다. 또한, 산화층의 기공률에 따라서 열전도도가 증가되는 비율의 차이가 발생하였다.

• Bulletin of the Korean Chemical Society
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• v.1 no.2
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• pp.54-57
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• 1980

Trichloromethylphosphonyl dichloride was prepared by the aluminium chloride method. We synthesized several heterocyclic compounds containing phosphorus atom by the stepwise esterification of trichloromethylphosphonyl dichloride with ethylene glycol, 2-mercaptoethanol, ethylene diamine, and 2-aminoethanol and the resulting heterocyclic compounds are 2-trichloromethyl-1,3,2-dioxa-, 2-trichloromethyl-1,3,2-thioxa-, 2-trichloromethyl-1,3,2-diaza-, 2-trichloromethyl-1,3,2-diaza-, and 2-trichloromethyl-1,3,2-oxazaphospholane-2-oxide. The best results were obtained in the solution of triethylamine as hydrochloric acid trapping agent. The structure of five-membered heterocyclic phosphonates were characterized by their IR, NMR, and elementary analysis and the mass spectra of the compounds were analyzed.

• Progress in Superconductivity and Cryogenics
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• v.10 no.1
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• pp.62-66
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• 2008

The characteristic of the superconducting magnetic energy storage(SMES) system is faster response, longer life time, more economical, and environment friendly than other uninterruptible power supply(UPS) using battery. So, the SMES system can be used to develop methods for improving power quality where a short interruption of power could lead to a long and costly shutdown. Recently, cryogen free SMES has developed using BSCCO(Bismuth Strontium Calcium Copper Oxide) wire. We fabricated and tested the conduction cooling system for the 600 kJ class HTS SMES. The experiment was accomplished for the simulation coils. The simulation coils were made of aluminium, it is equivalent to thermal mass of 600 kJ HTS SMES coil. The coil is cooled with two GM coolers through the copper conduction bar. In this paper, we report that the test results of cool-down and heat loads characteristics of the simulation coils. The developed conduction cooling system adapted to 600 kJ HTS SMES system and cope with the unexpected sudden heat impact, too.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.278.1-278.1
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• 2014

Organic materials have been explored as the gate dielectric layers in thin film transistors (TFTs) of backplane devices for flexible display because of their inherent mechanical flexibility. However, those materials possess some disadvantages like low dielectric constant and thermal resistance, which might lead to high power consumption and instability. On the other hand, inorganic gate dielectrics show high dielectric constant despite their brittle property. In order to maintain advantages of both materials, it is essential to develop the alternative materials. In this work, we manufactured nanocomposite gate dielectrics composed of organic material and inorganic nanoparticle and integrated them into organic TFTs. For synthesis of nanocomposite gate dielectrics, polyimide (PI) was explored as the organic materials due to its superior thermal stability. Candidate nanoprticles (NPs) of halfnium oxide, titanium oxide and aluminium oxide were considered. In order to realize NP concentration dependent electrical characteristics, furthermore, we have synthesized the different types of nanocomposite gate dielectrics with varying ratio of each inorganic NPs. To analyze gate dielectric properties like the capacitance, metal-Insulator-metal (MIM) structures were prepared together with organic TFTs. The output and transfer characteristics of organic TFTs were monitored by using the semiconductor parameter analyzer (HP4145B), and capacitance and leakage current of MIM structures were measured by the LCR meter (B1500, Agilent). Effects of mechanical cyclic bending of 200,000 times and thermally heating at $400^{\circ}C$ for 1 hour were investigated to analyze mechanical and thermal stability of nanocomposite gate dielectrics. The results will be discussed in detail.

• Clean Technology
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• v.3 no.2
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• pp.87-93
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• 1997

A new process has been developed for nitrate and other salts removals from polluted waters. Alumina cement and calcium oxide served as precipitating agents to remove nitrate with stirring at basic pH. Low content of alumina in the commercialized alumina cements resulted in a increasing in nitrate removal yield. It is found that the compositions of aluminium and calcium are the most important factors in successful nitrate insolubilization. In order to remove high concentration of nitrate in polluted water, multi-stage precipitation was found to be very effective. Sulfate, chloride, and phosphate ions as well as nitrate were also removed by the precipitated reaction. After precipitation, post-treatments including Na2CO3 addition and neutralization with acid alleviated the level of aluminium and calcium in the treated water.

• The Korea Journal of Herbology
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• v.25 no.4
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• pp.23-29
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• 2010

Objectives : To investigate the immunological activities, we evaluated the combination ratio of Aconiti Lateralis Radix Preparata and Glycyrrhizae Radix (AG) on murine macrophage cell line (RAW 264.7) and ovalbumin/aluminium (OVA/Alum)-immunized mice. Methods : The cellular proliferation and the production of nitric oxide were examined in a macrophage cell line, RAW 264.7 cells, in the presence of the combination ratio of Aconiti Lateralis Radix Preparata and Glycyrrhizae Radix. C57BL/6 mice were immunized intraperitonially with ovalbumin/aluminium ($100{\mu}g/200{\mu}g$) on day 1, 8, and 15. The combination ratio of Aconiti Lateralis Radix Preparata and Glycyrrhizae Radix (1 g/kg/day) was orally administrated for 3 weeks. On day 22, splenocyte and plasma were collected for mitogen-induced proliferation, lymphocyte subpopulation by flow cytometry and measurement of AST (Aspirate aminotransferase), ALT (Alanine aminotransferase), and antibodies (OVA-specific antibodies of the IgG, IgG1, and total IgM classes). Results : Aconiti Lateralis Radix Preparata treatment had no influence on immune responses. The proliferation and NO production of macrophage and proliferation of splenocyte were increased as the higher ratio of Glycrrhizae Radix. The proliferation of splenocyte, lymphocyte subpopulation and production of antibody (total IgM, OVA-specific IgG and OVA-specific IgG1) were increased as the higher ratio of Glycrrhizae Radix on OVA-immunzed mice. Conclusions : These results suggest that the higher ratio of Glycyrrhizae Radix can increase immunological activities such as NO production in RAW264.7 cells, splenocyte proliferation and immunoglobulin production in OVA-immunized mice.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.382-387
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• 2013

PURPOSE. Although several surface treatments have been recently investigated both under in vitro and in vivo conditions, controversy still exists regarding the selection of the most appropriate zirconia surface pre-treatment. The purpose of this study was to evaluate the effect of alumina (Al) and aluminium nitride (AlN) coating on the shear bond strength of adhesive resin cement to zirconia core. MATERIALS AND METHODS. Fifty zirconia core discs were divided into 5 groups; air particle abrasion with 50 ${\mu}m$ aluminum oxide particles ($Al_2O_3$), polishing + Al coating, polishing + AlN coating, air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + Al coating and air particle abrasion with 50 ${\mu}m$ $Al_2O_3$ + AlN coating. Composite resin discs were cemented to each of specimens. Shear bond strength (MPa) was measured using a universal testing machine. The effects of the surface preparations on each specimen were examined with scanning electron microscope (SEM). Data were statistically analyzed by one-way ANOVA (${\alpha}$=.05). RESULTS. The highest bond strengths were obtained by air abrasion with 50 ${\mu}m$ $Al_2O_3$, the lowest bond strengths were obtained in polishing + Al coating group (P<.05). CONCLUSION. Al and AlN coatings using the reactive magnetron sputtering technique were found to be ineffective to increase the bond strength of adhesive resin cement to zirconia core.

• Korean Journal of Materials Research
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• v.31 no.3
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• pp.150-155
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• 2021

Zinc oxide (ZnO) based transparent conducting oxides (TCO) thin films, are used in many applications such as solar cells, flat panel displays, and LEDs due to their wide bandgap nature and excellent electrical properties. In the present work, fluorine and aluminium-doped ZnO targets are prepared and thin films are deposited on soda-lime glass substrate using a RF magnetron sputtering unit. The aluminium concentration is fixed at 2 wt%, and the fluorine concentration is adjusted between 0 to 2.0 wt% with five different concentrations, namely, Al2ZnO98(AZO), F0.5AZO97.5(FAZO1), F1AZO97(FAZO2), F1.5AZO96.5(FAZO3), and F2AZO96(FAZO4). Thin films are deposited with an RF power of 40 W and working pressure of 5 m Torr at 270 ℃. The morphological analysis performed for the thin film reveals that surface roughness decreases in FAZO1 and FAZO2 samples when doped with a small amount of fluorine. Further, optical and electrical properties measured for FAZO1 sample show average optical transmissions of over 89 % in the visible region and 82.5 % in the infrared region, followed by low resistivity and sheet resistance of 3.59 × 10-4 Ωcm and 5.52 Ω/sq, respectively. In future, these thin films with excellent optoelectronic properties can be used for thin-film solar cell and other optoelectronics applications.