• Journal of Photoscience
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• v.5 no.3
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• pp.105-109
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• 1998

By using the liquid -phase-deposition (LPD) process, which has a potetnial of preparing organic inorganic composite materials, samples doped with benzo[f]quinoline (BfQ)into silica thia films wre prepared. We observed the fluorescene and fluorescene excitation spectra of the samples, as well as the fluorescence lifetimes and time-resoluved fluorescence spectra. The comparison of thefluorescence spectra in pH-controlled buffer solutions yields the results that the dominant species of BfQ in the LPD silica films is a protonated one. The fluorescence band assigned to a hydrogen-bonded species was observed on the samples prepared from the dipping solutions of 3 and 2 M hexafluorosilicic acid. The band assignment was confirmed by the fluorescence lifetime measurement. The FT-IR M hexaflurosilicic acid. The band assignment was confirmed by the flurescence lifetime meausurement. The FT-IR data proved the existence of included water in silica films prepared from the LPD process. The appearance of the band corresponding to the hydrogen-bonded species within LPD silica phases was explained by the proesence of included water. Depending on the preparation conditions of LPD silica films, the band assigned to protonated species shows bad shifts in a wavenumber region between the peak of hydrogen-bonded and typical protonated species. This implies that there is some distribution of steric conformation of protonated species of BfQ interacting with adsorbing sites of LPD silica. The time -resolved fluorescence spectra suggest that some relaxation process is involved in the conformation of BfQ doped into the solid phase of LPD silica.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.198-198
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• 2016

An ideal orthopedic implant should provide an excellent bone-implant connection, less implant loosening and minimum adverse reactions. Commercial pure titanium (CP-Ti) and Ti alloys have been widely utilized for biomedical applications such as orthopedic and dental implants. However, being bioinert, the integration of such implant in bone was not in good condition to achieve improved osseointegraiton, there have been many efforts to modify the composition and topography of implant surface. These processes are generally classified as physical, chemical, and electrochemical methods. Plasma electrolytic oxidation (PEO) as an electrochemical route has been recently utilized to produce this kind of composite coatings. Mg ion plays a key role in bone metabolism, since it influences osteoblast and osteoclast activity. From previous studies, it has been found that Mg ions improve the bone formation on Ti alloys. PEO is a promising technology to produce porous and firmly adherent inorganic Mg containing $TiO_2$($Mg-TiO_2$ ) coatings on Ti surface, and the amount of Mg introduced into the coatings can be optimized by altering the electrolyte composition. In this study, a series of $Mg-TiO_2$ coatings are produced on Ti-6Al-4V ELI dental implant using PEO, with the substitution degree, respectively, at 0, 5, 10 and 20%. Based on the preliminary analysis of the coating structure, composition and morphology, a bone like apatite formation model is used to evaluate the in vitro biological responses at the bone-implant interface. The enhancement of the bone like apatite forming ability arises from $Mg-TiO_2$ surface, which has formed the reduction of the Mg ions. The promising results successfully demonstrate the immense potential of $Mg-TiO_2$ coatings in dental and biomaterials applications.

• Journal of Technologic Dentistry
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• v.39 no.1
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• pp.25-33
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• 2017

Purpose: The aim of this study was to evaluate accuracy of glass fiber mesh complete denture of before and after curing. Methods: Edentulous model was selected as the master model. Ten study models were made by Type IV stone. Wax complete dentures were produced by the denture base and artificial teeth. CD and GD groups were measured six measurement distance before curing. The wax complete denture was investment after measurement is completed. Using a heat polymerization resin was injected resin. After injecting the resin it was curing. A complete denture was re-measured after curing. The measured data was verified by paired t-test. Results: Overall CD group was larger the value of the measured length. In the CD group, A-D point was larger. The smallest point was the B-D point. However, there was no statistically significant difference only C-D point(p>0.05). In the GD group, A-B point was larger. but B-D point was the smallest. A-D and B-C statistically points showed significant differences(p<0.05). Conclusion: Glass fiber mesh resin complete denture can be clinically applied to the edentulous patient.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.974-980
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• 2015

Arc thermal spray coating using Al-3%Mg thermal spray wire was carried out to prevent steel from corrosion damage under the marine environment. Post-sealing was applied to Al-3%Mg spray coating treatment using organic/inorganic composite ceramics in order to improve the corrosion resistance of the as-sprayed coating. The results of various electrochemical experiments with sealing treatment indicated that the improvement in corrosion resistance was observed due to low current density in all applied potential range during anodic and cathodic polarization experiments. Futhermore, the natural potential measurement exhibited severe potential fluctuation due to influence of micro-crack presence on the surface of sealed thermal spray coating layer. In addition, the sealed layer was easily eliminated during anodic polarization. Nevertheless, Al-3%Mg spray coating layer improved corrosion resistance by sealing treatment because the sealed coating efficiency was determined to be 92.11%, indicating the exterior environment barrier effect which is based on the Tafel analysis.

• Conservation Science in Museum
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• v.26
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• pp.35-66
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• 2021

This study conducted scientific analysis and conservation treatment on four suits of armor and two helmets from the collection of the National Museum of Korea. Based on the findings, it identified structural characteristics of armor from the middle and late Joseon Dynasty. Since a suit of armor is made of composite materials consisting of both organic and inorganic elements, conservation treatment was conducted to the extent that the stable condition of each material remained unaffected by the other materials. The process took place in the sequence of investigation and analysis, removal of contamination, stabilization and reinforcement, repair of damaged parts, and storage. The armor and helmets had suffered severe damage, but were safely repaired and partially restored through the conservation treatment. The findings from the conservation treatment revealed the materials used and structural characteristics of the armored skirt from a two-piece set of armor from the middle Joseon period and for the two suits of overcoat-style armor, suit of vest-style armor, and helmets from the late Joseon era. It also allowed the investigation of the production methods of the armor and helmets.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.335-342
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• 2022

In this study, self-healing hybrid capsules were prepared by mixing self-healing solid capsules and self-healing microcapsules using inorganic materials as core materials. Self-healing hybrid capsules were mixed with 3 % according to the composition ratio of 3:7, 5:5, and 7:3 based on the mass of the cement to prepare a self-healing cement composite material. The healing properties of crack self-healing hybrid capsules were evaluated through hydrostatic water permeability test and surface crack monitoring. It was found that the self-healing hybrid capsules prepared by mixing the composition ratio of the self-healing solid capsules and the self-healing microcapsules at 7:3 has a great effect on improving the crack self-healing performance.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.3
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• pp.685-692
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• 2024

Currently used heating elements are metal and non-metal heating elements, including various types of heaters, and resistance line heating elements have a problem of decreasing thermal efficiency over time, so to solve this problem, a planar heating element using high-purity carbon materials and oxidation-resistant inorganic compounds was applied. Through the manufacture of planar heating elements using CNT, ruthenium composite materials, and ruthenium oxide, physicochemical performance and capacity were increased, and instantaneous responsiveness was increased. Through thick film technology applicable to various base bodies, fine patterns were formed by the screening method in consideration of the fact that the performance of the heat source depends on the viscosity and pattern shape. The heating element was manufactured by thick film printing technology by mixing ruthenium oxide, CNT, Ag, etc. The characteristics of each paste were analyzed through viscosity measurement, and STS 430 was used as a base. Surface temperature and efficiency were measured by testing heaters manufactured for small wind tunnels and real-vehicle experiments. The surface temperature decreased as the air volume increased, and the optimal system boundary was found to be about 200 mm. Among the currently used heating elements, this paper manufactured a planar heating element using thick film technology to find out the relationship between air volume and temperature, and to study the surface temperature.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.1
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• pp.45-53
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• 2012

The metal chloride wastes from a pyrochemical process to recover uranium and transuranic elements has been considered as a problematic waste difficult to apply to a conventional solidification method due to the high volatility and low compatibility with silicate glass. In this study, a dechlorination approach to treat LiCl-KCl waste for final disposal was adapted. In this study, a $SiO_2-Al_2O_3-P_2O_5$ (SAP) inorganic composite as a dechlorination agent was prepared by a conventional sol-gel process. By using a series of SAPs, the dechlorination behavior and consolidation of reaction products were investigated. Different from LiCl waste, the dechlorination reaction occurred mainly at two temperature ranges. The thermogravimetric test indicated that the first reaction range was about $400^{\circ}C$ for LiCl and the second was about $700^{\circ}C$ for KCl. The SAP 1071 (Si/Al/P=1/0.75/1 in molar) was found to be the most favorable SAP as a dechlorination agent under given conditions. The consolidation test revealed that the bulk shape and the densification of consolidated forms depended on the SAP/Salt ratios. The leaching test by PCT-A method was performed to evaluate the durability of consolidated forms. This study provided the basic information on the dechlorination approach. Based on the experimental results, the dechlorination method using a $SiO_2-Al_2O_3-P_2O_5$ (SAP) could be considered as one of alternatives for the immobilization of waste salt.

• Korean Journal of Microbiology
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• v.12 no.4
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• pp.159-179
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• 1974

In order to investigate morphological and cultural characteristics of strains in species, Flammulina velutipes, the author collected isolates of Flammultina velutipes at 49 locations in Korea and cultivated these isolates on the various kinds of solid media. After investigating the cultural characteristics, appeared on the various media, he obtained the following results : 1. The variation of colors in the fruit bodies is connected with the variation of climatic environments(composite effects between mean temperature in January and number of rain days of 1mm and over precipitation). The author, therfore, can find out the trend that brown type is distributed in the midland climatic region and yellow type in the southern climatic regoin. 2. Two types can be classified into several strains respectively : the strain of abundant or insufficient productivity, and strain of selectivity or non-selectivity of media. 3. According to the results of mutual comparison of soluble mycelial proteins by disc electrophoresis using polyacrylamide gels, each type has special common protein fractions(brown type : band located at 26..5mm position from surface of gel, yellow type : band located at 24.5mm position from surface of gel), and each strain has special protein fractions too. Therefore this phenomenon seems to support the results obtained by the above-stated morphological and cultural studies. 4. In the adaptability of strains to the temperature, every strain has the nature of growing in lower temperature(the optimum temperature of 20.deg.C to 25.deg.C) except that YI-1 strain has the optimum temperatue of $25^{\circ}C$-26^{\circ}C. And mycelial growth of every strain is discontinued at $35^{\circ}C.$ 5. In the adaptability of strains to the H-ion concentration, every strain has wide adaptable range of H-ion concentration, and has optimum range of pH 5.5 to 6.6 in mycelial growth excepting YA01, BI-2 and YI-1. 6. In the utility of carbon sources, the mycelial growth of every strain is very poor on the media containing xylose(average diameter of mycelial growth : 18mm), and most strains utilize favorably sucrose(39mm), maltose(37mm) and dextrose(35mm) in mycelial growth. In the utility of nitrogen sources, every strain utilizes favorably organic nitrogens(36 mm)more than inorganic nitrogens (25 mm), and utilizes fully peptone nad asparagine in organic nitrogens. Especially BA-1, BIK-2 and YA-1 strains grow vigorously on each media containing various carbon and nitrogen sources. 7. The characteristic tests of the number of days required for mycelial growth, the number of days requried for sprout of young bodies, the length of stipe and the number of fruit bodies formation seem to be useful methods in the early selection of the strain of the abundant productivity.

• Corrosion Science and Technology
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• v.9 no.4
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• pp.147-152
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• 2010

Conventional paints for conversion coating applications in steel production derived mainly from water-based polymer dispersions containing several additives actually show good general performance, but suffer from poor scratch and abrasion resistance during use. The reason for this is because the relatively soft organic binder matrix dominates the mechanical surface properties. In order to maintain the high quality and decorative function of coated steel sheets, the mechanical performance of the surface needs to be improved significantly. In fact the wear resistance should be enhanced without affecting the optical appearance of the coatings by using appropriate nanoparticulate additives. In this direction, nanocomposite coating compositions (Nanomer$^{(R)}$) have been derived from water-based polymer dispersions with an increasing amount of surface-modified nanoparticles in aqueous dispersion in order to monitor the effect of degree of filling with rigid nanoparticles. The surface of nanoparticles has been modified for optimum compatibility with the polymer matrix in order to achieve homogeneous nanoparticle dispersion over the matrix. This approach has been extended in such a way that a more expanded hybrid network has been condensed on the nanoparticle surface by a hydrolytic condensation reaction in addition to the quasi-monolayer type small molecular surface modification. It was expected that this additional modification will lead to more intensive cross-linking in coating systems resulting in further improved scratch-resistance compared to simple addition of nanoparticles with quasi-monolayer surface modification. The resulting compositions have been coated on zinc-galvanized steel and cured. The wear resistance and the corrosion protection of the modified coating systems have been tested in dependence on the compositional change, the type of surface modification as well as the mixing conditions with different shear forces. It has been found out that for loading levels up to 50 wt.-% nanoparticles, the mechanical wear resistance remains almost unaffected compared to the unmodified resin. In addition, the corrosion resistance remained unaffected even after $180^{\circ}$ bending test showing that the flexibility of coating was not decreased by nanoparticle addition. Electron microscopy showed that the inorganic nanoparticles do not penetrate into the organic resin droplets during the mixing process but rather formed agglomerates outside the polymer droplet phase resulting in quite moderate cross linking while curing, because of viscosity. The proposed mechanisms of composite formation and cross linking could explain the poor effect regarding improvement of mechanical wear resistance and help to set up new synthesis strategies for improved nanocomposite morphologies, which should provide increased wear resistance.