• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.370.1-370.1
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• 2016

Volatile organic compounds (VOCs) are considered hazardous air pollutants and these are emitted from building materials and household products. VOCs can cause global warming as well as human sickness, and even cancer. Photocatalysis provides a way of converting VOCs into harmless materials. Various researches have shown that $TiO_2$ is the most efficient photocatalysts due to its excellent activity. In this study, metal/non-metal doped $TiO_2$ particles are synthesized for the enhancement of the photocatalytic properties of pure $TiO_2$. By metal/non-metal doping, band gap energies of prepared samples were analyzed by UV/Visible spectrophotometer. The physical and chemical properties of synthesized powder were characterized by field emission scanning electron microscope, by BET for measuring their specific surface area, and by XRD for phase identification and particle size determination. Degradation ability for p-xylene was evaluated through monitoring the concentration in a closed chamber. Relation between their properties and decomposition abilities for VOC were evaluated based on the experimental results.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.3
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• pp.203-210
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• 2006

Although porcelain fused to metal crowns made from non-precious metal have good mechanical properties, they also have disadvantages such as the poor biological acceptability and the low corrosional resistance. Titanium is used as the alternative metal for porcelain fused to metal crowns, in spite of difficulties in casting. For that reason non-precious alloy including titanium which is easy to cast is currently used. This study evaluated the bond strength between non-precious alloy including titanium and Ni-Cr alloy. $Tilite^{(R)}V$ as non-precious alloy including titanium, $Rexilium^{(R)}V$ as Ni-Cr alloy and $Omega900^{(R)}$ and $Vintage(Regular)^{(R)}$ as porcelain powders were used. The results were as follows. 1. In comparison with the kind of alloy, the bond strength of $Tilite^{(R)}V$ was lower than that of $Rexilium^{(R)}V$. There was no significant difference between two groups. 2. In comparison with the kind of porcelain powder, the bond strength of $Omega900^{(R)}$ was higher than that of $Vintage(Regular)^{(R)}$ in $Tilite^{(R)}V$. There was significant difference between two groups(p < 0.05).

• The Journal of Korean Academy of Prosthodontics
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• v.29 no.3
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• pp.181-196
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• 1991

The Purpose of this study was to evaluate the marginal fit of ceramo-metal crown according to the different ceramo-metal alloy types and the curvature of labio-cervical margin. Degudent $G^{(R)}$ as precious and $Verabond^{(R)}$ as non-precious ceramo-metal alloy were used. The abutment was preparaed with two different curvature types : a normal curvature type and a pronounced curvature type. 20 crowns were farbricated using four different combinations and their marginal fits were measured at 3 consecutive stages (before degassing, after degassing, after glazing) using microscope under 200 magnification. The results were as follows: 1 . Marginal fitness before degassing. The groups of precious ceramo-metal exhibited better marginal fit than the groups of non-precious ceramo-metal with significant difference(P<0.05) . In the same ceramo-metal groups, the normal curvature group exhibited better marginal fit than the pronounced curvature group but without significant difference(P>0.05). 2. Marginal fitness after degassing. By degassing, the group of pronounced curvature and non-precious ceramo-metal was deformed the most, and the degree of margin fitness of each group was the same as before degassing. 3. Marginal fitness after glazing The group of normal curvature and precious ceramo-metal exhibited better marginal fit than the group of pronounced curvature and non-precious ceramo-metal with significant difference(P>0.05), and the degree of margin fitness of each group was the same as before degassing.

• Journal of Technologic Dentistry
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• v.34 no.4
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• pp.337-344
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• 2012

Purpose: This study examined the corrosion level by alloy type and pH, and used the corrosion levels as the dental health data. The study utilized one Ni-Cr alloy for the full and removable partial denture metal frameworks and two Ni-Cr alloys for porcelain-fused-to-metal crown, among the non-beryllium dental casting non-precious Ni-Cr alloys. Methods: The alloy specimens were manufactured in $10cm^2$ and stored in the corrosive solution(pH 2.2-4.4) in the electrical water bath($37^{\circ}C$) for seven days. Afterwards, the metal ions were quantitatively analyzed using the ICP. Results: Of the three metal alloys, Bellabond-Plus$^{(R)}$alloy and SOLIBOND N$^{(R)}$alloy, with 22% or higher chrome chemical contents, had higher corrosion resistance than Jdium-100$^{(R)}$alloy with 20% chrome chemical content. In all three alloys, the corrosion of Ni was highest, and metal ion corrosion was higher in the pH 2.2 corrosive solution. Conclusion: Although Ni-Cr alloy was not very corrosive, a Ni-allergic patient should not have Ni-Cr alloy prosthesis. The Ni-Cr alloy for porcelain-fused-to-metal crown should be designed for the dental porcelain to cover the whole crown.

• Journal of Korean Society for Quality Management
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• v.42 no.2
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• pp.179-187
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• 2014

Purpose: Since several problems were found when present non-conducting metal coating process was applied to mass production, we study and develop to improve those problems. Methods: In this paper, a couple of analysis methods such as surface hardness, XPS spectrum analysis, morphology, and reflection ratio were used. Results: This paper suggest a new possibility of Non-conducting thin metal coating method that has quality of mass production phase without UV coating process. Conclusion: By the result of analysis, we can set optimized process conditions of the electro deposition coating using electron beam.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3183-3189
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• 2010

In order to increase the specific capacitance and energy density of supercapacitors, non-aqueous supercapacitors were prepared using lithium transition-metal oxides and activated carbons as active materials. The electrochemical properties were analyzed in terms of the content of lithium transition-metal oxides. The results of cyclic voltammetry and AC-impedance analyses showed that the pseudocapacitance may stem from the synergistic contributions of capacitive and faradic effects; the former is due to the electric double layer which is prepared in the interface of activated carbon and organic electrolyte, and the latter is due to the intercalation of lithium ($Li^+$) ions. The specific capacitance and energy density of a supercapacitor improved as the lithium transition-metal oxides content increased, showing 60% increase compared to those of supercapacitor using a pure activated carbon positive electrode.

• Journal of Magnetics
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• v.21 no.4
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• pp.635-643
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• 2016

Improvements were made in the study for the design of the conventional Eddy Current Separator (ECS) used for separating small sized non-ferrous particles in the waste. These improvements include decreasing the air gap between the material and magnetic drum, making the drum position adjustable and placing the splitter closer to the drum. Thus, small particles were separated with high efficiency. The magnetic drum was removed from inside the ECS conveyor belt system as design change and was placed as a separate unit. Hence, the force generated on the test material increased by about 5.5 times while the air gap between the non-ferrous materials and drum decreased from 3 mm to 1 mm. The non-metal material in the waste is separated before the drum in the novel design. Whereas non-ferrous metal particles are separated by falling into the splitter as a result of the force generated as soon as the particles fall on the drum. Every material that passes through the drum can be recycled as a result of moving the splitter closer to the contact point of the drum. In addition, the drum can also be used for the efficient separation of large particles since its position can be adjusted according to the size of the waste material. The performance of the novel design ECS was verified via analytical approaches, finite element analysis (FEA) and experimental studies.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.3
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• pp.199-207
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• 2018

In this paper, an all-metal domestic induction heating (IH) system that can quickly identify ferromagnetic and non-ferromagnetic pots considering temperature changes in the working coil is designed. Load modeling is performed after analyzing the parameters of the pot material and the central misalignment of the working coil. To improve the performance and stability of the all-metal IH cooking heater, a power curve-fitting model is used to design a control system that quickly responds to load parameter fluctuations. In addition, a power control algorithm is established to compensate for the reference value by reflecting the increase in working coil temperature during heating of the non-ferromagnetic pot. The validity of the proposed control algorithm for the all-metal IH is verified by experiments using a 3.2 kW all-metal IH cooking heater.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.09a
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• pp.235-240
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• 2004

This study is to study accumulation of the heavy metals by riparian vegetation throughout analysis of the heavy metal concentration in riparian vegetation, water, and sediment near mine drainage. According to analyzing concentration of the heavy metals in riparian vegetation, water, and sediment, the heavy metal was indicated at the leaf significantly. Compared with the concentration of sediment soil, the maximum concentration of the As, Cd, CN, Pb, Zn was higher 2.6, 2.6, 2.5, non-detect, and 1.5 times in leaf, Also those concentration have 9.6, 16.6, 2.5, 1.6, and 2.5 times in root. As the results, the author can know the sediment has a very relative to vegetation in mine drainage, because the increasing of concentration of heavy metal in sediment gives the more accumulative concentration of heavy metal in vegetation. Compared with the concentration of contaminated site and non-contaminated site. As, Cd, CN, Pb, Zn the maximum concentration in sediment soil was higher 5.7, 258.1, 10.9, 370.0, and 298.3 times respectively. In case of vegetation, the maximum concentration of the As, Cd, CN, Pb, Zn was higher 5.6, 62.3, 5.0, non-detect, and 30.6 times in leaf. Also those concentration have 8.5, 63.3, 2.6, 60.7, and 62.1 times in root. In this study, the author can surmise that there indicated a lot of adsorption with the heavy metal concentration in contaminated mine drainage.

• Journal of Technologic Dentistry
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• v.33 no.2
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• pp.121-128
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• 2011

Purpose: The purpose of this study is to investigate the level of each metal in non-precious metal alloys dental casting, still used even banned for use and trade by the law, for oral health. Methods: Two kinds of metal alloys were analyzed. One was Ticonium 100 for removable prosthesis and the other was Rexillium V for dental porcelain. Two samples of each metal alloy were made in 0.5g, 1.0g, and 1.5g. Total number of samples were 12. Two kinds of lactic acid Solution, pH7 and pH4.6, were injected into each samples. After injection, each samples had been for 21days ${\pm}$ 1 hour in the water tank of which temperature was $37^{\circ}C$. The level of metal was measured in each sample by inductively couplled plasma-atomic emission spectrometer. Results: In both metal alloys, metals, chrome, nickel, beryllium, and molybdenum, were founded. In Ticonium 1000, the highest level of nickel was 2.531ppm in 1.5g pH4.6 sample while the highest level of nickel was 4.062ppm in 1.5g pH4.6 sample of Rexillium V. In chemical composition of these methal alloys, chrome(14~17%) was much more than beryllium(1.95~1.99%) and molybdenum(5.0~9.0%) but berllium and molybdenum were founded more than chrome in samples. Therefore, chrome showed better anti-corrosion than other metal alloys. In both metal alloys, more metals were founded in higher pH level and more mass. Levels of chrome was significantly different in samples of both metal alloys in each pH level(p<0.05). Levels of nickels was significantly different in samples of both metal alloys in each pH level(p<0.05). Conclusion: For oral health, further studies are needed in nickel-chrome metal alloy and cobalt metal alloy of non-beryllium in addittion to beryllium metal alloy and also long-term studies needed in various period and other non-percious metal alloys for dental casting.