• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.5
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• pp.384-393
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• 1998

A mixed powder of electrolyte and matrix support materials with a proper proportion was used for the fabrication of an electrolyte matrix sheet. The purpose of this study is to reduce the large change in MCFC cell thickness occurring in the initial start-up period when separate sheets of electrolyte and support are used. A focus was put on how small the carbonate particles could be made. The particle size of the carbonate powder was controlled by ball milling and the distribution was measured using a particle size analyser. The thickness change was reduced to 20% by this approach, which could be compared to 27% observed in a conventional cell. The thickness changes of electrolyte matrix have linear relation sizes of carbonate powders.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.520-524
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• 1999

Light-emitting diode(LEDs), diode arrays, and phosphor display panels are finding increased use in a variety of commercial applications. Present and anticipated application of these devices include solid state indicator and display systems. In this work, Phosphor based on ZnS:Cu are used. Relation by luminance with the thickness of insulating layer and phosphor layer are discussed. Increased thickness of insulating layer are stable on voltage to 300V. By considering thickness and voltage, optimal structure and thickness are investigated. In order to maximize even surface emission, various sieving processes are introduced. 150cd/m$^2$ luminance by various wave intensity are investigated in stable voltage and frequency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.535-536
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• 2005

Organic photovoltaic effects were studied in a device structure of ITO/CuPc/Al and ITO/CuPc/$C_{60}$/BCP/Al. A thickness of CuPc layer was varied from 10 nm to 50 nm, we have obtained that the optimum CuPc layer thickness is around 40 nm from the analysis of the current density-voltage characteristics in CuPc single layer photovoltaic cell. From the thickness-dependent photovoltaic effects in CuPc/$C_{60}$ heterojunction devices, higher power conversion efficiency was obtained in ITO/20nm CuPc/40nm $C_{60}$/Al, which has a thickness ratio (CuPc:$C_{60}$) of 1:2 rather than 1:1 or 1:3. Light intensity on the device was measured by calibrated Si-photodiode and radiometer/photometer of International Light Inc(IL14004).

• Steel and Composite Structures
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• v.29 no.5
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• pp.591-602
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• 2018

This research presents an investigation on the thermal buckling resistance of FGM plates having parabolic-concave thickness variation exposed to uniform and gradient temperature change. An analytical formulation is derived and the governing differential equation of thermal stability is solved numerically using finite difference method. A specific function of thickness variation is introduced where it controls the parabolic variation intensity of the thickness without changing the original material volume. The results indicated that the loss ratio in buckling resistance is the same for any gradient temperature profile. Influencing geometrical and material parameters on the loss ratio in the thermal resistance buckling are investigated which may help in design guidelines of such complex structures.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.30.1-33
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• 1999

Finite element simulation with experimental analysis of Taguchi's orthogonal array was carried out to know the effects of material and forming parameters on the cup earing and skewness. It was revealed that the planar anisotropy was the most influencing factor in the cup ear formation whereas blank holding force and material properties such as strength and thickness deviation at the coil edge had a relatively high effect on the cup skewness.

• Tunnel and Underground Space
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• v.14 no.5
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• pp.318-326
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• 2004

In this study, a new direct shear apparatus was developed to investigate the shear characteristics of the rock joints at various conditions. Using the developed apparatus, various experiments on filled rock joints were carried out considering the asperity angle, the normal stress, the type and thickness of filling material and to investigated the basic shear characteristics of filled rock joints were analyzed. According to the experiments performed under the constant normal stress condition by varying the asperity angle, the type and thickness of filling material, it was shown that the behavior and strength of filled rock joint could be defined by the type and thickness of the filling material. The dilation angle of the filled joints was found to be smaller than that of unfilled rock joint, and thereby, the effect of roughness was also reduced due to the filling material. And critical thickness ratio varied according to stress level and roughness as well as the type of filing materials.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.427-436
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• 2014

The goal of this paper is to estimate proper hardfacing material and thickness of STD61 hot-working tool steel through three-dimensional heat transfer and thermal stress analyses. Stellite6, Stellite21 and 19-9DL superalloys are chosen as alternative hardfacing materials. The influence of hardfacing materials and thicknesses on temperature, thermal stress and thermal strain distributions of the hardfaced part are investigated using the results of the analyses. From the results of the investigation, it has been noted that a hardfacing material with a high conductivity and a thinner hardfaced layer are desired to create an effective hardfacing layer in terms of heat transfer characteristics. In addition, it has been revealed that the deviation of effective stress and principal strain in the vicinity of the joined region are minimized when the Stellite21 hardfaced layer with the thickness of 2 mm is created on the STD61. Based on the above results, a proper hardfacing material and thickness for STD61 tool steel have been estimated.

• Food Science and Preservation
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• v.9 no.2
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• pp.148-153
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• 2002

Effect of the thickness of low density polyethylene(LDPE) Film as packaging material on changes in physicochemical characteristics of mature-green mume (Prunus mume Sieb. et Zucc) fruits during storage at different temperatures(0, 10 and 25$\^{C}$) were investigated. Fruit samples stored in pouches with 30㎛ thickness of LDPE film maintained well not only external qualities such as Shape and firmness, but also internal chemical properties such as pH, acidity, the content of soluble solid and chlorophyll, and color, comparing with samples stored without packaging material or in other pouches with different film thickness(20 and 40㎛). From the results, it was found that the maintenance of quality of mature-green mume fruits during storage at 0, 10 and 25$\^{C}$ closely related to the changes in respiratory conditions for fruits affected by the film thickness of the packaging material.

• The Journal of Advanced Prosthodontics
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• v.13 no.4
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• pp.226-236
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• 2021

PURPOSE. This study aimed to evaluate the effect of incorporating zirconium oxide nanoparticles (nano-ZrO₂) in polymethylmethacrylate (PMMA) denture base resin on flexural properties at different material thicknesses. MATERIALS AND METHODS. Heat polymerized acrylic resin specimens (N = 120) were fabricated and divided into 4 groups according to denture base thickness (2.5 mm, 2.0 mm, 1.5 mm, 1.0 mm). Each group was subdivided into 3 subgroups (n = 10) according to nano-ZrO₂ concentration (0%, 2.5%, and 5%). Flexural strength and elastic modulus were evaluated using a three-point bending test. One-way ANOVA, Tukey's post hoc, and two-way ANOVA were used for data analysis (α = .05). Scanning electron microscopy (SEM) was used for fracture surface analysis and nanoparticles distributions. RESULTS. Groups with 0% nano-ZrO₂ showed no significant difference in the flexural strength as thickness decreased (P = .153). The addition of nano-zirconia significantly increased the flexural strength (P < .001). The highest value was with 5% nano-ZrO₂ and 2 mm-thickness (125.4 ± 18.3 MPa), followed by 5% nano-ZrO₂ and 1.5 mm-thickness (110.3 ± 8.5 MPa). Moreover, the effect of various concentration levels on elastic modulus was statistically significant for 2 mm thickness (P = .001), but the combined effect of thickness and concentration on elastic modulus was insignificant (P = .10). CONCLUSION. Reinforcement of denture base material with nano-ZrO₂ significantly increased flexural strength and modulus of elasticity. Reducing material thickness did not decrease flexural strength when nano-ZrO₂ was incorporated. In clinical practice, when low thickness of denture base material is indicated, PMMA/nano-ZrO₂ could be used with minimum acceptable thickness of 1.5 mm.

• Proceedings of the KIEE Conference
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• 1995.07c
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• pp.1388-1390
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• 1995

The characteristic of dielectric breakdown in solid insulating material dominates the reliability and safety of power equipment and affects directly to its life. In this point of view, the thickness and temperature dependence of dielectric breakdown strength and mechanism of dielectric breakdown in low density polyethylene which has been employed widely as insulating material have been technically reviewed by examinations of thermal property. The dielectric breakdown strength depending on its thickness was measured 2.6[MV/cm] at the thickness of 20[${\mu}m$] and 1.9[MV/cm] at the thickness of 75[${\mu}m$] based on ambient temperature of 30[$^{\circ}C$]. It is shown the temperature dependence that dielectric breakdown strength decreases in linear as the thickness increases. The dielectric breakdown strength depending on temperature was measured 2.6[MV/cm] at the temperature of 30[$^{\circ}C$], 1.6[MV/cm] at 60[$^{\circ}C$] and 1.3[MV/cm] at 90[$^{\circ}C$] based on the thickness of 20[${\mu}m$]. As the ambient temperature increases, the temperature dependence is shown that a very large drop is occurred up to temperature of 60[$^{\circ}C$] and a very small drop is discovered over 60[$^{\circ}C$].