• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.253-259
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• 2004

The Jeju Island in Korea is the clean area which the tradition culture is preserved locally well with the nature environment of Heaven's blessing. An air pollution is becoming recently serious problem as the industrial development is proceeded with the urbanization. This study investigates that the atmosphere environment at Jeju area influences on the metal corrosion. A study of the atmosphere corrosion for carbon steel, copper, zinc ana aluminium exposed on five test sites indoors and outdoors. Corrosion results are treated statistically and adjusted to a model previously proposed for carbon steel, copper, zinc and aluminium based on the influence of environmental parameters and main pollutants($SO_2$ and chlorides) on tire atmosphere corrosion of metals. Through this study, we try to set the standards atmosphere corrosion at Jeju Island.

• Journal of Ocean Engineering and Technology
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• v.19 no.5 s.66
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• pp.50-57
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• 2005

This study has been conducted to investigate corrosivity of carbon steel, Cu, Zn and Al for one year from Sept. 2003 to Aug. 2004. A model of ISO 9223-ISO 9226 that represents the relation between metal corrosions and environmental parameters was used for atmospheric corrosion evaluations. Environmental parameters for these evaluations are time of wetness(TOW), $SO_2$ and Chloride. Corrosion rates for four metals which are exposed indoors and outdoors were measured on five locations in Jeju Island; Gosan, Seogwipo, Seongsan, Chuna hill and Jeju city. The environmental factor of atmospheric corrosion of Jeju Island for $SO_2$ class is P0, a clean area. TOW as T3 and T4 indicates that Jeju has the characteristics of a tropical area. Chlorides class within 3 km from the coast show the features of costal area as S2 and S3 classes. Chuna hill show the features of woodland as a S1 class. In Corrosion classes of each site which was measured outdoors is higher than indoors. Gosan is the highest class as the rank of C5, and indicated that they're ranked as C3 or C4.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.46-50
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• 2005

BST thin films were etched with inductively coupled CF$_{4}$/(Cl$_{2}$+Ar) plasmas. The etch characteristics of BST thin films as a function of CF$_{4}$/(Cl$_{2}$+Ar) gas mixtures were analyzed using optical emission spectroscopy (OES) and Langmuir probe. The BST films in CF$_{4}$/Cl$_{2}$/Ar plasma is mainly etched by the formation of metal chlorides which depends on the emission intensity of the atomic Cl and the bombarding ion energy. The maximum etch rate of the BST thin films was 53.6 nm/min because small addition of CF$_{4}$ to the Cl$_{2}$/Ar mixture increased chemical and physical effect. A more fast etch rate of BST films can be obtained by increasing the DC bias and the RF power, and lowering the working pressure.

• Bulletin of the Korean Chemical Society
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• v.17 no.11
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• pp.1061-1065
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• 1996

The charge transfer compounds of tetrathiafulvalene (TTF) with the general formula of (TTF)mMCln, (M=Au, Pt, Ir, Os) were prepared by the direct reaction using excess HAuCl4·3H2O, H2PtCl6·xH2O, H2IrCl6·xH2O and H2OsCl6 respectively. The powdered electrical conductivities (σrt) at room temperature are given as follows; (TTF)3AuCl2, 4.53×10-3; (TTF)3.5AuCl2, 6.37×10-3; (TTF)3PtCl4, 5.51×10-4; (TTF)2IrCl4, 2.40×10-5; (TTF)OsCl4·1/2C2H5OH, 4.46×10-7 Scm-1. Magnetic susceptibility, electronic (UV-Vis.), vibrational (IR) and EPR spectroscopic evidences indicate that there is incomplete charge transfer from the TTF donor to gold, platinum, and iridium respectively, and that there is essentially complete charge transfer to osmium, thereby resulting a relatively low electrical conductivity in osmium compound. The EPR and magnetic susceptibility data reflect that the metals are in diamagnetic Au(Ⅰ), Pt(Ⅱ), Ir(Ⅲ), and Os(Ⅱ) oxidation states, and the odd electrons are extensively delocalized over the TTF lattices in each compound.

• Korean Journal of Materials Research
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• v.14 no.9
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• pp.634-641
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• 2004

The photocatalytic performance of $TiO_2$ thin films coated on porous alumina balls using various aqueous $TiOCl_2$ solutions as starting precursors, to which 1.0 $mol\%$ transition metal ($Ni^{2+},\;Cr^{3+},\;Fe^{3+},\;Nb^{3+},\;and\;V^{5+}$) chlorides had been already added, has been investigated, together with characterizations for $TiO_2$ sols synthesized simultaneously in the same autoclave through hydrothermal method. The synthesized $TiO_2$ sols were all formed with an anatase phase, and their particle size was between several nm and 30 nm showing ${\zeta}-potential$ of $-25{\sim}-35$ mV, being maintained stable for over 6 months. However, the $TiO_2$ sol added with Cr had a much lower value of -potential and larger particle sizes. The coated $TiO_2$ thin films had almost the same shape and size as those of the sol. The pure $TiO_2$ sol showed the highest optical absorption in the ultraviolet light region, and other $TiO_2$ sols containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ showed higher optical absorption than pure sol in the visible light region. According to the experiments for removal of a gas-phase benzene, the pure $TiO_2$ film showed the highest photo dissociation rate in the ultraviolet light region, but in artificial sunlight the photo dissociation rate of $TiO_2$ coated films containing $Cr^{3+},\;Fe^{3+}\;and\;Ni^{2+}$ was measured higher together with the increase of optical absorption by doping.

• Polymer(Korea)
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• v.24 no.6
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• pp.802-809
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• 2000

Counterion-specific helix formation and ion-selective transport of alkali metal chlorides (LiCl, NaCl, KCl, CsCl) were investigated for a poly(L-glutamic acid)(PLGA)/poly (vinyl alcohol)(PVA) blend membrane immersed in aqueous ethanol. The counterion specificity for helix formation of PLG alkali metal salts in the membrane was Li>Na>K>Cs. This specificity is ascribed to a contact ion-pair formation between the PLG carboxyl anion and the bound counterion, which depends on the energy balance between the electrostatic interaction and the desolvation. In aqueous ethanol, an appreciable ion-selectivity was observed for the permeability coefficient, i.e. Li$^{+}{\cdot}$Cl$^{-}$) formation between counterion and coion, and the latter to a specific interaction of diffusing counterions with polymer charges.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.286-293
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• 1998

Two methods were used to enhance the adsorption capacity of activated carbons. One is to impregnate activated carbons with chemical compounds which have a good affinity for $CO_2$. The other is to activate by heat-treating after impregnation with KOH on activated carbons(AC). The chemical compounds impregnated on AC were alkali metal, alkaline earth metal, and transition metal chlorides. The adsorption capacity of $CO_2$ on AC impregnated with these metals was less than that of pure AC. These compounds have not the chemical affinity for $CO_2$ and obstruct the micropore of AC. The experiment of breakthrough for $CO_2$ on AC impregnated with KOH showed the increase of the adsorbed amount of $CO_2$ in influent gases containing water vapor. This means that KOH adsorbes $CO_2$ gas. However, the adsorbents impregnated with KOH had not the reproducibility because of the production of $K_2CO_3$ by the reaction of KOH with $CO_2$. The amount of $CO_2$ adsorbed on the heat-treated AC at $800^{\circ}C$ increased with the amount of impregnation. The adsorption capacity of $CO_2$ was the largest when the ratio of weight of KOH to AC equal to 4. The isosteric heat of adsorption was calculated by the equation of Clausius-Clapeyron form adsorption capacity data of $CO_2$ for the temperature change. In addition, the characteristics of $CO_2$ breakthrough curve were surveyed for the change of flow rate and concentration.

• Korean Journal of Food Science and Technology
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• v.9 no.2
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• pp.157-164
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• 1977

In the present study, the proxidant effect of ferrous and cupric chlorides which added to soybean oil and its fried noodle in the same concentration of the city water and the physically refined underground water were determined. As the inhibitor of metal proxidation, BHA and citric acid which are used widely in oil industry as antioxidants were compared. In both cases of soybean oil and its fried noodle, the addition of cupric chloride and ferrous chloride showed prominent proxidant effect. Especially, cupric chloride marked more proxidant effect than ferrous chloride by 3 to 6 times with the elapse of time. In the inhibition activity of metal proxidation, citric acid was more effective than BHA. The 1ppm of Cu +0.01% of citric acid treated soybean oil showed less proxidant effect than the control at the later stage. The inhibition activity of citric acid on $Fe^{++}$ in soybean oil was more effective than $Cu^{++}$ in soybean oil.

• The Journal of Advanced Prosthodontics
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• v.9 no.2
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• pp.118-123
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• 2017

PURPOSE. To investigate the effect of non-thermal atmospheric pressure plasma (NTAPP) treatment on shear bond strength (SBS) between resin cement and colored zirconia made with metal chlorides. MATERIALS AND METHODS. 60 zirconia specimens were divided into 3 groups using coloring liquid. Each group was divided again into 2 sub-groups using plasma treatment; the experimental group was treated with plasma, and the control group was untreated. The sub-groups were: N (non-colored), C (0.1 wt% aqueous chromium chloride solution), M (0.1 wt% aqueous molybdenum chloride solution), NP (non-colored with plasma), CP (0.1 wt% aqueous chromium chloride solution with plasma), and MP (0.1 wt% aqueous molybdenum chloride solution with plasma). Composite resin cylinders were bonded to zirconia specimens with MDP-based resin cement, and SBS was measured using a universal testing machine. All data was analyzed statistically using a 2-way ANOVA test and a Tukey test. RESULTS. SBS significantly increased when specimens were treated with NTAPP regardless of coloring (P<.001). Colored zirconia containing molybdenum showed the highest value of SBS, regardless of NTAPP. The molybdenum group showed the highest SBS, whereas the chromium group showed the lowest. CONCLUSION. NTAPP may increase the SBS of colored zirconia and resin cement. The NTAPP effect on SBS is not influenced by the presence of zirconia coloring.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.729-736
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• 1997

For the recovery of industrial waste heat, a chemical heat transformer based on the reversible reaction between metal chlorides and ammonia gas was designed and a pilot scale unit of 1 kW-1hr was developed. A static calculation, which determined the amount of reacting materials and operating condition of system, and dynamic simulations were performed for the optimal design. The temperature and output power of generator in the system were varying with the amount of salt and heat exchange area. Optimum conditions such as the amount of salt-graphite, apparent density and size of mechanical unit were determined by the dynamic simulation for the system. According to the operating cycle of 4 stages, experimental results of temperature and output power were well agreed with the simulation values. This chemical heat transformer is turned out to be a very promising system for recovery of industrial waste heat because of its effective feature of lifting temperature.