• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.123-126
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• 1999

On this study, CaCO3(CF) treated with H2SiF6 as a fluorine copmpound and analyzed its basic property. When CF added with cement and mortar, we also examined effect of CF on the physical property of cement and mortar.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.79-86
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• 2022

With the recent increase in the demand for electric vehicles, it is necessary to identify the high current safety of automobile parts. Among the automobile parts, the EPDM parts required colored parts from the existing black; therefore, it was necessary to change the basic filler from carbon black to silica. The rubber used in automobile parts is flexible and exhibits basic characteristics of high strength and elongation. However, as the filler is changed to silica, its physical properties, such as tensile strength and elongation, are lower than those of the existing carbon black base. Therefore, it is necessary to evaluate the mechanical properties with the addition of the EPDM compound using silica as a base without degrading the physical properties of EPDM. In this study, an experiment based on the additive content was performed using the mixture experimental planning method to analyze the mechanical properties according to the additive type and mixing ratio of silica-based EPDM. The mixing ratio of the four additives was set using a simplex lattice design, and the tensile strength, elongation, modulus 300%, and permanent compression reduction rate were analyzed for mechanical characteristics, and rheometer experiments were performed for vulcanization characteristics. Through statistical analysis of the measured data, the main effects and interactions of the EPDM-blended rubber additives were analyzed. These results can be used to derive a mixing ratio of additives that satisfies the required characteristics of the EPDM compound.

• Bulletin of the Korean Chemical Society
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• v.33 no.9
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• pp.2999-3003
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• 2012

Various types of room temperature ionic liquids (RTILs) containing 1,1-dicyano-1-acetylmethanide anion ($[C(CN)_2(COCH_3)]^-$, $[DCNAcC]^-$) were prepared and their physical and electrochemical properties were studied. All of these ILs exhibited high thermal stabilities over $200^{\circ}C$ and relatively high ionic conductivities up to 29.4 $mS\;cm^{-1}$ at $80^{\circ}C$. Although the ionic conductivity of IL containing bis(trifluoromethanesulfonyl)-imide ($[Tf_2N]^-$) anion is higher than that of ILs bearing $[DCNAcC]^-$ anion, the specific capacitance of ILs bearing $[DCNAcC]^-$ anion are higher than that of IL containing $[Tf_2N]^-$ anion and showed high temperature dependence. Such favorable electrochemical properties of these ILs are likely to be attributed to the efficient dissociation of cation and anion at higher temperature and enhanced electrosorption of $[DCNAcC]^-$ anion at the electrode.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.98-100
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• 1989

Langmuir-Blodgett(LB) technique will be used to produce ultra thin film, and then characterization of the physical and electrical properties of LB ultra thin films, this study will be an investigation for the possibilities of the ultra thin films as an Molecular Electronic Device.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.400-401
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• 2005

• Journal of Oriental Neuropsychiatry
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• v.23 no.3
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• pp.33-46
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• 2012

Objectives : Emotion is composed by several basic feelings. This basic feeling is called Chiljung in Oriental Medicine. This study examines the positive and negative affects related to Chiljung. Methods : A total of 199 students of Dongshin university oriental medicine were tested by Questionnaire for Sasang Constitution ClassificationII(QSCCII) and Positive Affect and Negative Affect Schedule(PANAS). This study is used 156 students' data, excluding 43 students' data. Of the enrolled 156 students, four groups were classified by QSCCII. The positive and negative properties of Chiljung were determined by PANAS. These data were analyzed by frequency, Pearson's chi-square test, Crosstabulation Analysis with SPSS windows 15.0. Results : 1. Joy(喜) and Anger(怒) has directly-opposed emotional properties. 2. Thought(思) difficult to tell the difference between positive and negative, but it is distinct from Anxiety(憂) and Sorrow(悲) 3. Anxiety(憂) and Sorrow(悲) are superior in negative emotional properties. 4. Fear(恐) and Fright(驚) are superior in negative emotional properties, and Fright(驚) is superior over Fear(恐) in positive emotional properties. Conclusions : This study may serve as the foundation in identifying the psychological traits of Chiljung.

• Journal of the Korean Wood Science and Technology
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• v.16 no.3
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• pp.22-37
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• 1988

In tendancy of manufacturing beam with laminating particleboard, it was thought that if the properties, especially mechanical properties, of particleboard be reinforced, the mechanical properties of particleboard-laminated beam would be also improved. So in this study the particleboard was reinforced with composing of wood particle and steel wire. This study was carried out to obtain the basic physical and mechanical properties of board composed of wood particle and steel wire, especially tensile strength and compressive strength which are the important factors of the lamina of beam, in order to estimate whether the board, composed of wood particle and steel wire could be to improve the properties of the particleboard- laminated beam. The results obtained were summarized as follows: 1. The board composed of wood particle and steel wire in accordance with lower board density took better thickness swelling. 2. The board with lower board density was improved in higher value of tensile strength with more steel wires in prescribed cross section area of the board. for example, the board of density 0.5 showing 140% improved value. 3. In compressive strength, the board with lower board density was also improved in hjgher value with more steel wires in prescribed cross section area.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.257-262
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• 1997

Reinforced concrete structures built on the seashore or in seawater are damaged from saltwater which cause to accelerate corrosion of reinforcing steel in concrete. Therefore, Corrosion of steel reinforcement of concrete structures become more and more serious, and prediction of service lives of concrete structures considering steel corrosion is needed much more. this research is to investigate basic physical properties of various corrosion inhibitors and to evaluate their corrosion resistance in concrete. The object of this study is develop appropriate corrosion protection systems so as to enhance the durability of concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.57-60
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• 2004

Recently. as the alternatives to preserve environment such as effective usage of wastes or unusable resources are drawing attentions, researches and measures for the two tasks, which are reuse of waste wood and development of eco-friendly materials, are being examined and established in various fields. However, they are still insufficient. Therefore, in this study, for the efficient application of waste woods and eco-friendly effects, mortar was produced using sawdust af the waste wood and mineral material cement for combination, in order to produce inorganic boards using waste woods, which were made when sawing. The present study purposed to analyze the physical and dynamic characteristics of woody cement boards, which were made by modifying water-cement ratio for each wood inclusion rate based on a hardening-accelerator inclusion rate set in previous studies and, based on the findings. to provide basic data about the physical properties of inorganic boards made of waste wood, in order to Produce woody cement boards using waste wood, which has problems in being used in the manufacturing of woody cement boards.

• Journal of the Korea Institute of Building Construction
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• v.7 no.4
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• pp.117-124
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• 2007

Focused on the material-related aspect for enhancing the durability of concrete, the present study analyzed the effect of glycol ether admixture, which is a chemical admixture that can compact the structure of concrete by entraining air inside the concrete, on the basic physical properties and durability characteristic of the concrete. In analyzing the results of experiment, we examined the basic physical properties and durability characteristic of concrete according to addition rate based on OPC and selected the optimal addition rate. In addition, with the optimal addition rate, we added glycol ether admixture to concrete, which contained fly ash used as binder and high-performance water reducing agent for reducing the unit quantity, and examined changes in the characteristics of the concrete. According to the result, the optimal addition rate of glycol ether admixture was 3% of the unit quantity of cement, and the addition of binder and chemical admixture did not have a significant effect on unhardened concrete but reduced the air content. In addition, concrete showed resistance performance of around 30% to carbonation and around 40% to drying shrinkage. In addition, as for resistance to freezing and thawing, the relative dynamic modulus of elasticity was over around 85% through atmospheric curing. These performances prove the effect.