• Journal of the Korean Ceramic Society
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• v.50 no.5
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• pp.326-332
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• 2013

In this study, we prepared yttria stabilized zirconia granules for thermal barrier coatings using a spray drying process. First, we characterized the properties of granules such as flow rate and packing density for utilizing the air plasma spray process. The flow rate and packing density data showed 0.732 g/sec and 2.14 $g/cm^3$, respectively, when we used larger and denser particles, which are better than hollow granules or smaller spherical granules. Second, we chose larger, spherical granules fabricated in alcohol solvent as starting powders and sprayed it on the bondcoat/nimonic alloy by an atmospheric plasma spray process varying the process parameters, the feeding rate, gun speed and spray distance. Finally, we evaluated representative thermal and mechanical characteristics. The thermal expansion coefficients of the coatings were $11{\sim}12.7{\times}10^{-6}/^{\circ}C$ and the indentation stress measured was 2.5 GPa at 0.15 of indentation strain.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.4
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• pp.96-106
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• 2017

In pressable polymer bonded explosives (PBXs), densification occurs due to rearrangement and deformation of explosive particles during pressing. If brittle explosives are compressed till particle fraction become higher than theoretical random close packing fraction (RCPF), bigger particles should be fractured to fill the void. In this study, multi-modal particle system was introduced for the decrease in possibility of particle fracture during compression expecting decrease in shock sensitivity of highly filled pressable PBX. The experimental results showed the trimodal particle system had low sensitivity with high density, compared to bimodal particle system.

• Hwankyungkyoyuk
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• v.12 no.1
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• pp.225-241
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• 1999

The art subject deals with aesthetic experience within natural environment around and artificial environment, and it represents the experience through formative arts. And it also extends the aesthetic experience by making students appreciation of the works of art. In the main text of this study was studied with the connection with environmental education on the basis of the characteristics of art subject. That is, in the art education there can be an understanding of the harmony between natural environment and artificial one and their relationship and, furthermore, more positive environmental education can be possible by environmental murals, environmental sculpture, environmental design, packing design, poster design, elf through systematic formative arts. In addition, the art education can make students keep sensitivity to the natural and artificial environment through the appreciation of a variety of art works made with a theme of environment or through the appreciation of the works in the environment around our lives. Also, it can lead to acquire the desirable values and attitudes toward the environment by discussing the harmony of environmental development and environmental preservation visually. In the second place, this relation described in detail by each grade according to the contents of the 7th curriculum for the art subject. In the third place, the following were suggested: the goals for the environmental education in the art subject, the direction of environmental education, the organization of contents related to environment and their emphases, and the main teaching and learning methods for environmental education.

• Journal of Environmental Health Sciences
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• v.19 no.4
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• pp.38-43
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• 1993

The characteristics of food wastewater treatment in an anaerobic packed bed reactor (APBR) with polyurethane as a packing material and sludge bed reactor (ASBR) was studied. The reactor of 9cm-ID, 150cm-height was fed in a continuous mode from bottom of reactor. For the purpose of constant temperature of reactor, water jacket was installed. The used packing materials was polyurethane sponge foam. Methane which was produced by decomposed organics collected at the top of the reactor for using as a fuel. The substrates used were synthetic, mixed and food wastewater. For the acclimatization of microorganisms, mixed wastewater was used. The major analyses were gas production, COD, pH and volatile acids. Based upon the completed works, the results are as follows: When food wastewater was fed the quantity of produced gas was less than that of synthetic wastewater, but food process saw higher methane content than synthetic process. As well as COD removal efficiency of food process reached at about 85%. In aspect of effluent volatile acid, food process showed low concentration of below 500 mg/l, therefore anaerobic reaction stabled. Conclusively food wastewater used can be digested by anaerobic treatment, especially anaerobic packed bed reactor showed 82% of COD removal, 75% of methane content, 10 l of gas production, and anaerobic sludge bed reactor did 79% of COD removal, 75% of methane content, 81 of gas production at 4 kgCOD/m$^3$day, 36$\circ$C.

• Design & Manufacturing
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• v.16 no.3
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• pp.1-8
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• 2022

In this study, an artificial neural network(ANN) was constructed to establish the relationship between process condition prameters and the qualities of the injection-molded product in the injection molding process. Six process parmeters were set as input parameter for ANN: melt temperature, mold temperature, injection speed, packing pressure, packing time, and cooling time. As output parameters, the mass, nominal diameter, and height of the injection-molded product were set. Two learning structures were applied to the ANN. The single-task learning, in which all output parameters are learned in correlation with each other, and the multi-task learning structure in which each output parameters is individually learned according to the characteristics, were constructed. As a result of constructing an artificial neural network with two learning structures and evaluating the prediction performance, it was confirmed that the predicted value of the ANN to which the multi-task learning structure was applied had a low RMSE compared with the single-task learning structure. In addition, when comparing the quality specifications of injection molded products with the prediction values of the ANN, it was confirmed that the ANN of the multi-task learning structure satisfies the quality specifications for all of the mass, diameter, and height.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.75-79
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• 1997

Optical and mechanical characteristics of $TiO-2, ZrO_2 \;and\; SiO_xN_y$ thin films prepared by ion assisted deposition (IAD) were investigated. IAD films were bombarded by Ar or nitrogen ion beam from a Kaufman ion source while they were grown in as e-beam evaporator. The result shows that the Ae IAD increases the refractive index and packing density of $TiO_2 films close to those of the bulk. For $ZrO_2$ films the Ar IAD increases the average refractive index decreases the negative inhomogeneity of refractive index and reverses to the positive inhomogeneity. The optical properties result from improved packing density and denser outer layer next to air The Ar-ion bombardment also induces the changes in microstructure of $ZrO_2$ films such as the preferred (111) orientation of cubic phase increase in compressive stress and reduction of surface roughness. Inhomogeneous refractive index SiOxNy films were also prepared by nitrogen IAD and variable refractive index of $SiO_xN_y$ film was applied to fabricate a rugate filter.

• Macromolecular Research
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• v.10 no.5
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• pp.278-281
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• 2002

We investigated the photoluminescence (PL) characteristics of a highly soluble, fullerene-containing copolymer in both solution and film states. In solution state, the copolymer showed different PL characteristics depending on the aromaticity of the solvent. The PL from polystyrene segments of the copolymer was strongly quenched in an aromatic solvent, while the PL from fullerene remained unchanged. However, the films cast from an aromatic and a nonaromatic solvent demonstrated very similar PL characteristics, implying that the chain alignment or orientation and packing in the films occur in a similar way irrespective of the solvent.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.443-444
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• 2012

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1117-1122
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• 2001

This study is to investigate application to the load packing or block with photocatalystic which has the characteristics absorption and removal for NOx, which is mainly generated from plant or car, which can be resolved by actions of light. Therefor a basic study was carried out to maximize the photocatalystic block for elimination of NOx.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.1101-1106
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• 2000

When top down method is used, it could be a construction method trouble in column joint, between the former concrete and the latter. It could bring a void and weak concrete in column. The purpose of this study is to find a solution of removing void and air, way to exhaust air in top down column. through specimen concrete placing experiment.