• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.7
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• pp.55-61
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• 2014

This paper presents a method to reduce the stray loss of core Tie-Plate of distribution power transformer. The method combines a 3-dimensional FEM with PSO(Particle Swarm Optimization) algorithm to determine the shape of the Tie-Plate that minimizes eddy current and flux-leakage losses. To verify the method a 24MVA distribution(cast-resin) transformer was simulated using one objective function and two design variables with some constraints. The final optimized Tie-Plate has nine($3{\times}3$) slots of 10mm width, 15mm thickness and 25mm distance. After four iterations, the Tie-Plate loss was reduced to about 21 % of the original.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.570-571
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• 2003

This study was done to evaluate the shear bond strength between light-cured glass ionomer cement base and resin cement for luting indirect resin inlay and to observe bonding aspects which is produced at the interface between them by SEM(Scanning Electron Microscope). 1)Shear bond strength. Light-cured glass ionomer cement base were made in plastic molds(10mm diameter, 5mm thickness). Two type of light cured glass-ionomer cement were uesd.(중략)

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.7
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• pp.667-672
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• 2004

An experimental study has been carried out to investigate the frosting behavior on the plate of thermally conductive plastic (PBT based resin) by comparing it with those of aluminum and some plastic test specimens (PTFE based resin). It is found that the frosting behavior of plastic specimens with 1 mm thickness shows similar trend to that of aluminum except PTFE. The properties of frost formed on the specimens are found to be affected by both thermal conductivity and surface characteristics of the materials. The results indicate that the heat and mass transfer rates of PBT resin are almost equivalent to those of aluminum.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.25-26
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• 2022

In this study, glued laminated timber were manufactured by different types of adhesives for larch and spruce. Adhesives used to manufacture glued laminated timber include resorcinol resin, phenol resorcinol resin, melamine resin, and polyurethane. The char thickness and char rate according to the type of adhesive forglued laminated timber were analyzed. Melamine, resorcinol, and polyurethane showed excellent fire resistance performance in that order.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.4
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• pp.351-365
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• 2001

For accurate impression taking, accurate impression material, solid individual tray, and bond strength between impression materials and resin tray are important factors. The purpose of this study was to evaluate tensile bond strength of rubber impression materials to various tray resin materials. This study tested the time dependent tensile bond strength between commercial brands or poly ether, polysulfide, additional silicone impression materials and commercial brands of self curing tray resin. light activited tray resin when applying adhesive Resin specimens were made with 20mm in diameter, 2mm in thickness. 1 made total 360 specimens, 10 per each group and the tensile bond strength was measured by using the Instron($M100EC^{(R)}$, Mecmesin Co., England). The results were as follows ; Comparisons of various impression materials. 1. In case of Impregum $F^{(R)}$, the bond strength of tray resin was decreased in order of SR $Ivolen^{(R)}$, Ostron $100^{(R)}$ Instant tray $mix^{(R)}$, $Lightplast^{(R)}$. All groups excluding Ostron $100^{(R)}$, Instant tray $mix^{(R)}$ are significant difference (p<0.05). Drying time after applying adhesive, the tensile bond strength of tray resin was insignificantly decreased in order of 10 min drying time group. 1 min drying time group. 5 min drying time group. 2. In case of Permlastic $regular^{(R)}$ the bond strength of tray resin was insignificantly decreased in order of Ostron $100^{(R)}$. SR $Ivolen^{(R)}$, Instant tray $mix^{(R)}$ $Lightplast^{(R)}$. About drying time after applying adhesive, the tensile bond strength of tray resin was significantly decreased in order of 5 min drying time group, 10 min drying time group, 1 min drying time group(p<0.05). 3. In case of Exaflex $regular^{(R)}$. the bond strength of tray resin was decreased in order of $Lightplast^{(R)}$, SR $Ivolen^{(R)}$, Instant tray $mix^{(R)}$, Ostron $100^{(R)}$. $Lightplast^{(R)}$ was significant difference(p<0.05). About drying time after applying adhesive, the tensile bond strength of tray resin was decreased in order of 5 min drying time group, 10 min drying time group, 1 min drying time group(p<0.05). Especially 5 min ding time group was significant difference(p<0.05). According to the results of this study, we can see the greatest tensile bond strength when using Impregrm $F^{(R)}$ and Permlastic $regular^{(R)}$ with self curing tray resin, when using Exaflex $regular^{(R)}$ with light activated tray resin In my opinion, adhesive should be dried more than 5 min before impression taking to achieve the greatest tensile bond strength.

• Analytical Science and Technology
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• v.15 no.3
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• pp.236-242
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• 2002

A method was investigated to determine the thickness of coating on steel sheet using rf glow discharge atomic emission spectrometer. The RF gas-jet boosted glow discharge has such salient feature as good pleasure stability and high sputtering efficiency that it was possible to determine the thickness of silicon resin film on zinc electroplated steel. The erosion speed variation is dependent on discharge power, gas flow rate and discharge pressure. therefore determine discharge condition to measure the thickness of coating on steels. The fundamental studies have been carried out to investigate an optimum condition for in-depth analysis and composition of zinc coating on steel. In this study, the calibration curve for thickness determination of silicon resin film was found to be linear in the range of $1000{\sim}3500mg/m^2$ film thickness. The developed rf gas-jet boosted glow discharge was applied to the analysis of zinc coating and silicon resin film on steel made by RIST.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.18-25
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• 1998

The purpose of this study was to determine how to use soft relining material by observing an amount of denture displacement according to the different base area of residual ridge and thickness of soft relining material under masticatory force. Stone models that simulated residual ridge were made with different amount of denture base area and denture was fabricated by conventional heat curing resin with usual manner on the model and relined by silicone type soft relining material with different thickness. Specimen was examined the amount of denture displacement by Instron within range of normal occlusal force. The results were as following : 1. The increasing rate of denture displacement was higher than that of soft relining material thickness. 2. The amount of denture displacement decreased 1.7 times when base area became double at same thickness of soft relining material 3. The increasing rate of denture displacement was higher than that of occlusal force

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.96-99
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• 2011

Fiber coatings are essential in optical fiber manufacturing, since they provide the protective layers from the surface damages and the adequate fiber strength. Flow and temperature fields of coating liquid in a fiber coating applicator are numerically investigated by using a commercial CFD software. The main focus of this computational study is on the thermal effects by viscous dissipation and the effects of coating supply temperature on the final fiber coating thickness. The numerical results reveal that the thermal effects play a major role in the high-speed optical fiber coating process and give substantial influences on the determination of coating thickness. Changing the supply temperature of coating liquid is found to relieve the radial variation of coating liquid viscosity in the coating die and it can be an effective way to control the fiber coating thickness.

• Restorative Dentistry and Endodontics
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• v.37 no.4
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• pp.194-200
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• 2012

Objectives: New resin cement (NRC) has been developed as a root repairing material and the material is composed of organic resin matrix and inorganic powders. The aim of this study was to compare the rat subcutaneous tissue response to NRC and mineral trioxide aggregate (MTA) cement and to investigate the tissue toxicity of both materials. Materials and Methods: Sixty rats received two polyethylene tube-implants in dorsal subcutaneous regions, MTA and NRC specimens. Twenty rats were sacrificed respectively at 1, 4 and 8 wk after implantation and sectioned to 5 ${\mu}m$ thickness and stained with Hematoxylin-Eosin (H-E) or von-Kossa staining. The condition of tissue adjacent to the implanted materials and the extent of inflammation to each implant were evaluated by two examiners who were unaware of the type of implanted materials in the tissues. Data were statistically analyzed with paired t-test (p < 0.05). Results: In specimens implanted with both NRC and MTA, severe inflammatory reactions were present at one wk, which decreased with time. At eighth wk, MTA implanted tissue showed mild inflammatory reaction, while there were moderate inflammatory reactions in NRC implanted tissue, respectively. In NRC group, von-Kossa staining showed more calcification materials than MTA group at eighth wk. Conclusions: It was concluded that the calcium reservoir capability of NRC may contribute to mineralization of the tissues.

• Transactions of Materials Processing
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• v.18 no.3
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• pp.268-273
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• 2009

Ultraviolet nanoimprint lithography (UV-NIL), which is performed at a low pressure and at room temperature, is known as a low cost method for the fabrication of nano-scale patterns. In the patterning process, maintaining the uniformity of the residual layer is critical as the pattern transfer of features to the substrate must include the timed etch of the residual layer prior to the etching of the transfer layer. In pursuit of a thin and uniform residual layer thickness, the initial volume and the position of each droplet both need to be optimized. However, the monomer mixtures of resin had a tendency to evaporate. The evaporation rate depends on not only time, but also the initial volume of the monomer droplet. In order to decide the initial volume of each droplet, the accurate prediction of evaporation behavior is required. In this study, the theoretical model of the evaporation behavior of resin droplets was developed and compared with the available experimental data in the literature. It is confirmed that the evaporation rate of a droplet is not proportional to the area of its free surface, but to the length of its contact line. Finally, the parameter of the developed theoretical model was calculated by curve fitting to decide the initial volume of resin droplets.