• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.2
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• pp.121-126
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• 2015

In general, the pearlescent pigment is a pigment which was used for optical characteristics like pearl, rainbow and metallic luster. Titanium dioxide coated mica plate developed by DuPont in 1965 is currently being used as a main part of pearlescent pigment for cosmetics. Although the smooth and clear surface substrate laminated with 2 ~ 3 ingredients is thicker than a previous monolayer coated substrate, it has been applied for cosmetics as the optical interference powder to realize stronger shine and brighter interference color than monolayer one. In this study, we developed a new optical interference powder with thinner and higher chroma than a current pearlescent pigment for the strong luster and bright interference color. It was prepared from the manufacturing process, in which the coated titanium dioxide precursor was changed and crystallized by coating and heat treatment process with a half of dividing the coated amount of titanium dioxide. We confirmed the dense coating of titanium dioxide grain with Scanning Electron Microscope and measured superior crystallization degree compared with a monolayer coated pearlescent pigment by X-ray Diffraction. It is concluded that our new pearlescent pigment had higher reflectivity of light and stronger interference color than previous products.

• Journal of the Korean Magnetics Society
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• v.14 no.4
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• pp.131-137
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• 2004

For the aim of thin electromagnetic wave absorbers used in mobile telecommunication frequency band (0.8-2.0㎓), we investigate high-frequency magnetic, dielectric and microwave absorbing properties of iron particles dispersed in rubber matrix in this study. The major experimental variables are particle shape (sphere and flake) and initial particle size (in the range 5-70 $\mu\textrm{m}$) of iron powders. High value of magnetic permeability and dielectric permittivity can be obtained in the composites containing thin plate-shape (flake) iron particles (of which thickness is less than skin depth in ㎓frequency), which can be produced by mechanical forging of spherical iron powders using an attrition mill. This result is attributed to the reduction of eddy current loss (increase of permeability) and the increase of space charge polarization (increase of permeability). The optimum initial particle size is found to be about 10 $\mu\textrm{m}$ for the attainment of the material parameters (particularly, real part of complex permeability) satisfying the wave impedance matching. With the iron powders controlled in size and shape as absorbent fillers in rubber matrix, the thickness can be reduced to about 0.7mm with respect to -5㏈ reflection loss (70% power absorption) in mobile telecommunication frequency band.

• Journal of the Korea Concrete Institute
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• v.20 no.2
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• pp.231-237
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• 2008

This study was performed to evaluate joint behavior of prestressed concrete(PSC)-steel mixed girders through the flexural test of 14 beams according to embedded length, amount of reinforcing steel, stud arrangement, and prestressing force. All test beams were failed by turns of desertion of reinforcing steel, stud, and steel plate. From test results, prestressing force was more effective on performance of connection than stud arrangement and reinforcing steel. And the spacing of stud is also more effective than embedding length. This paper also presented 3D nonlinear analysis considering the slip of composite section as well as the static load tests of PSC-steel mixed girders. According to the slip modulus, the nonlinear analysis showed that the behavior of hybrid girders could be divided into three parts as full-composite, partial-composite and non-composite. However, the experimental results showed that the PSC-steel hybrid girders with shear connectors took the part of partial composite action in ultimate load stage. In addition, it was founded that stud shear connectors and welded reinforcements were contributed to improve the ultimate strength of hybrid girders for about 20%.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.683-691
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• 2003

Recently, the steel has been increaseingly used as an integrated part of high-rise buildings, which often composed of steel structures, steel reinforced concrete structures and composite structures. The steel base is designed to transfer the stresses induced from steel column to the reinforced concrete footing through the base plate. However, in the design of steel structures and steel reinforced concrete structure, it is generally difficult to evaluate the bearing strength of the steel base subjected to large axial force. Furthermore, the material used in steel base is quite different from those used in other connections and a load transferring mechanism of steel base is very complicated in nature. Therefore, a special attention must be placed in design and construction of steel base. In generally, the bearing strength test and research of the steel base subjected to concentrated load are carried out. But, in the design of the structures, uniaxial eccentric load is loaded to the steel base of the steel structures. In this research, the bearing strength and the me of failure considering eccentric loads and eccentric length, were experimented when eccentric load is loaded to the steel base of steel structures. Based on the test results, a basic design reference is suggested for a reasonable design of steel structures, steel reinforced concrete structures and composite structures.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.423-430
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• 2013

An algorithm to allow shoreline movement during numerical experiment on sediment transport, deposition or resuspension for general coastal morphology is proposed here. The bed slope near shoreline, i.e. mean sea level, is influenced by bed material, tidal current, waves, and wave-induced current, but has been reported to remain within a stable range. Its annual variation is not large, either. The algorithm is adjusting the bathymetry, if the largest bed slope within shoreline band exceeds a given bed slope due to continuous erosion at zones below the shoreline. This algorithm automatically describes retreat of shoreline caused by erosion, when used within a numerical system. The algorithm was tested to a situation which includes a continuous dredging at a point, and showed satisfactory development of concentric circle contours. Next, the algorithm was tested to another situation which includes sinking of eroded part of bed plate, and produced satisfactory results, too. Finally, the algorithm was tested to a movable-bed laboratory experimental conditions. The shoreline movement behind detached breakwater was reasonably reproduced with this algorithm.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.459-463
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• 2017

Hot dip galvanizing in the steel plant is one of the most widely used methods for preventing the corrosion of steel materials including structures, steel sheets, and materials for industrial facilities. While hot dip galvanizing has the advantage of stability and economic feasibility, it has difficulty in repairing equipment and maintaining the facilities due to high-temperature oxidation caused by Zn Fume where molten zinc used in the open spaces. Currently, SM45C (carbon steel plate for mechanical structure, KS standard) is used for the equipment. If a part of the equipment is resistant to high temperature and Zn fume, it is expected to improve equipment life and performance. In this study, the manufactured Ni alloy was tested for its corrosion resistance against Zn fume when it was used in the hot dip galvanizing equipment in the steel plant. Two kinds of materials currently used in the equipment, new Ni alloy and Inconel(typical corrosion-resistant Ni alloy), were selected as the reference groups. Two kinds of molten metal were used to confirm the corrosion of each alloy according to the molten metal. Zn fume was generated by bubbling Ar gas from molten Zn in a furnace($500{\sim}700^{\circ}C$) and the samples were analyzed after 30 days. After 30 days, the specimens were taken out, the oxide layer on the surface was confirmed with an optical microscope and SEM, and the corrosion was confirmed using a potentiodynamic polarization test. Corrosion depends on the type of molten metal.

• Korean Journal of Veterinary Service
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• v.44 no.3
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• pp.149-155
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• 2021

In virucidal efficacy testing, the chemical inactivation cannot be determined for all viruses due to the difficulties or the inability to culture sufficiently or the risk of exposure to the viruses. Therefore, disinfectants against these viruses could be evaluated by different methods and surrogate viruses are used as alternative. In this study we developed a method for efficacy testing of veterinary disinfectants using one of the candidate surrogate viruses, bacteriophage MS2, as part of the research on the selection of surrogate viruses for efficiency of efficacy testing of veterinary disinfectants. This method is based on the Animal and Plant Quarantine Agency (APQA) guidelines for efficacy testing of veterinary disinfectants. Bacteriophage and disinfectant are reacted in suspension in accordance with the APQA guidelines and then a newly established double agar layer method is applied for the efficacy test. The double agar layer method is summarized as follows: 1) The bottom agar with 1.5% agar is boiled and cooled before poured into petri dishes at volume of 20 mL, and dried under biological safety cabinet. 2) The top agar with 0.7% agar is boiled and kept at 50℃ before E. coli culture was seeded. 3) The serially diluted bacteriophage MS2-disinfectant mixtures 0.05 mL and E. coli host 0.01 mL (OD₆₀₀ 0.2~0.3) are mixed with 5 mL of top agar and incubate them at 50℃ for 5 min for reaction. 4) The resulting mixture is poured over top of a bottom agar plate and rocked sufficiently to ensure that the top agar covers the entire surface of the bottom agar. 5) The double agar layer is then placed under biological safety cabinet to allow the agar layer to solidify and subsequently incubated at 37℃ for 24 hr. 6) Following incubation, the plates may be inspected for plaques and record results.

• Conservation Science in Museum
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• v.26
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• pp.67-82
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• 2021

Two golden beads (Buyeo 5336) housed at the Buyeo National Museum were discovered in 1993 near the site of an ancient workshop in Neungsan-ri in Buyeo-gun, Chungcheongnam-do Province. These rare examples from the Baekje Kingdom of an application of granulation have maintained their original form intact, and thus serve as important materials for the investigation of production techniques applied. This study analyzed the composition of the golden beads using a portable X-ray fluorescence analyzer, a stereo microscope, and a scanning electron microscope with an energy dispersive X-ray spectrometer. The manufacturing technique was examined through the observation of the micro-shape and the surface condition and by a composition analysis of the joint part. In both beads, a hole was pierced in a hollow body and the bead was decorated with golden wires around the hole and gold granules in other parts. In some areas, golden granules had been attached to the gold plate and golden wires were then placed over the granules. The purity of both the wires and the granules was analyzed as 23.6 - 23.7K. A high copper content was detected in some of the parts where the granules were attached. The findings of a previous reproduction experiment and study of production methods suggest that the beads were made using the copper diffusion technique.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.648-656
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• 2022

As environmental regulations such as the International Maritime Organization (IMO)'s strategy to reduce greenhouse gases(GHG) are strengthened, technology development such as eco-friendly ships and alternative fuels is expanding. As part of this, ship propulsion technology using energy reduction and wind propulsion technology is emerging, especially in shipping companies and shipbuilders. By securing wind propulsion technology and introducing empirical research into shipbuilding and shipping, a high value-added market using eco-friendly technology can be created. Moreover, by reducing the fuel consumption rate of operating ships, GHG can be reduced by 6-8%. Rotor Sail (RS) technology is to generate a hydrodynamic lift in the vertical direction of the cylinder when the circular cylinder rotates at a constant speed and passes through the fluid. This is called the Magnus effect, and this study attempted to propose a plan to increase propulsion efficiency through a numerical analysis study on turbulence flow characteristics around RS, a wind power assistance propulsion system installed on a ship. Therefore, C_L and C_D values according to SR and AR changes were derived as parameters that affect the aerodynamic force of the RS, and the flow characteristics around the rotor sail were compared according to EP application.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2001.06a
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• pp.95-95
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• 2001

The Yeongdong basin is one of the pull-apart basins in the southwestern part of the Korean Peninsula that has developed during Cretaceous sinistal fault movement. The bimodal igneous activities (basalts and rhyolites) in the basin appear to be closely associated with the basin development. Here, we discuss the origin of the igneous rocks using chemical and radiogenic isotope data. Basaltic (48.4-52.7 wt% SiO$_2$) and rhyolitic (70.3-70.8 wt% SiO$_2$) rocks are slightly alkalic in a total alkali-silica diagram. The rhyolitic rocks with have unusually high K$_2$O contents (5.2-6.0 wt%). The basaltic rocks show an overall pattern of within-plate basalt in a MORB-normalized spider diagram, but have distinct negative anomaly of Nb, which indicates a significant amount of crustal component in the magma. The basaltic rocks plot within the calc-alkaline basalt field in the Hf/3-Th-Ta and Y/l5-La/10-Nb/8 discrimination diagrams. The eNd(T) values of the basaltic rocks (-13.6 to 14.3) are slightly higher than those of the rhyolitic rocks (-14.1 to 15.2), and the initial Sr isotopic ratios of the former (0.7085-0.7093) are much lower than those of the latter (0.7140-0.7149). However, the initial Nd and Sr isotope ratios of the igneous rocks in the Yeongdong basin are similar to those of the nearby Cretaceous igneous rocks in the Okcheon belt. The Pb isotope ratios plot within the field of Mesozoic granitoids outside of the Gyeongsang basin in Pb-Pb correlation diagrams. Since a basaltic magma requires the mantle source, the enriched isotopic signatures and negative Nb anomaly of the basaltic rocks suggest two possibilities for their origin: enriched mantle lithospheric source, or depleted mantle source with significant amount of crustal contamination. However, we prefer the first possibility since it would be difficult for a basaltic magma to maintain its bulk composition when it is significantly contaminated with granitic crustal material. The slightly more enriched isotopic signatures of rhyolitic rocks also suggest two possibilities: differentiate of the basaltlc magma with some crustal contamination, or direct partial melting of the lower crust. Much larger exposed volume of the rhyolitic rocks, compared with the basaltic rocks, indicates the latter possibility more favorable.