• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.3
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• pp.180-184
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• 2017

In this study, we examine the electrical properties of diketopyrrolopyrrole (DPP) containing polymer semiconductors that have been reported to show high performance with ambipolar characteristics. We prepared three different DPP based polymer semiconductors (PDPPTPT, PDPP3T, and PDPP2T-TT) and fabricated organic thin film transistors (OTFTs) with ambipolar polymer semiconductors as an active layer. All three DPP polymers showed only p-type properties at initial measurements. However, after annealing in vacuum oven for 24 hours, it was found that the DPP based polymers have both p-type and n-type properties. It is speculated that the residual impurities supposedly regarded as a strong electron trap source were eliminated during the vacuum process.

• Journal of the Korea Concrete Institute
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• v.11 no.4
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• pp.137-145
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• 1999

The use of steel fiber reinforced to improve the strength and flexural toughness of concrete is well known, but reinforcement of polymer concrete with steel fibers has been hardly reported till now. Polymer concrete has high strength, durability and freeze-thaw resistance than that of cement concrete, but it has disadvantage such as low flexural toughness. In this paper, the strength characteristics and flexural toughness of steel fiber reinforced polymer concrete are investigated experimentally with various steel fiber aspect ratios($\ell$/d), and contents(vol.%). As the result, the flexural and splitting tensile strengths and flexural toughness were increased aspect ratio, and reach the maximums at a aspect ratio of 50. The relationship between the compressive, flexural and splitting tensile strength were high. And the relationship between flexural strength and strain energy was approximately linear.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.113-114
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• 2014

Though polymer cement mortar is widely used to repair or reinforce concrete as it has superior adhesion, dense internal structure, chemical resistance, and workability in comparison to those of general cement mortar, studies on its behaviors in high temperature environment such as fire is urgently required. Accordingly, in this experiment, the degrees of reduction in the compressive strength at different temperatures was grasped applying ISO834 Heating Curve, and the effect of polymer content and type on compressive strength could be determined. As a result of this experiment, it is found that polymer type and content have a big effect on reduction of compressive strength in high temperature range, and not only the dynamic characteristics but also the combustion characteristics in high temperature range are required to be studied considering occurrence of a fire in the future.

• Proceedings of the Membrane Society of Korea Conference
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• 1999.07a
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• pp.83-86
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• 1999

The imidization effect of a poly (amic acid) dope solution on membrane formation has been investigated. Poly (amic acid) solution in S-methyl-2-pyrrolidione hs been thermally imidized at $120^{\circ}C$ with different curing time and its degree of imidization was determined by infrared spectroscopy. The solution properties have been studied as a function of concentration and curing time by dynamic light scattering. The quality of a solvent was changed from good to poor with increasing imidization of poly(amic acid).The reduced polymer-solvent interaction diminishes the membrane formation time. The morphology of a membrane was able to be controlled by the characteristics of dope solution.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.04a
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• pp.1-4
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• 1990

This study was conducted to evaluate strength characteristics of various polymer concretes which were produced using materials available in Korea. Compressive strength, splitting tensile strength and flexural strength were evaluated in this study. Eight different polymer binders were used, including two types of epoxy resin, five types of unsaturated polyester resin, and a type of MMA monomer. The results of this study showed that the product made from PC-100 of SH company was the best performing concrete. However, since this result was based on strength and economics point of view, further study has to be conducted for comprehensive analysis.

• Journal of the Korean Society of Safety
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• v.5 no.1
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• pp.7-18
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• 1990

This study measured the smouldering temperature of dust layer for various combustible natural polymer material by practical apparatus. The dust layer was either put on the preheated plate of constant temperature, or formed with cylinderical metal sleeve of various diameters and depths at room temperature and then heated up to a pre-determined smouldering temperature. Plots of arrival times versus smouldering temperature were made to compare the smouldering characteristics with kinds of dusts. The natural polymer material was divided into theree groups by characteristics of smouldering mechanism. This groups are cellulose group, lipide group and glucose group.

• Proceedings of the Safety Management and Science Conference
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• 2001.11a
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• pp.157-160
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• 2001

The electrodes were fabricated by compounding the commercial activated carbons and additives of conducting polymer with PVdF mono binder and PVdF-PVP mixed binders. The best performance of the electrodes fabricated with activated carbon(BP-20) and PVdF-PVP mixed binders showed in 88wt. ％ BP-20. 7wt. ％ conducting polymer and 5wt.％ PVdF-PVP mixed binder. The electrode exhibited excellent electrochemical characteristics having 8.16 W.h/kg of energy density, 34.77 F/g of specific capacitance, $0.67\Omega$of ESR.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.522-525
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• 1999

The electrical characteristics of 3 year field-aged polymer insulators which dismounted from five regions were investigated. There was a little difference in PD inception voltage depending on the manufacturers and the regions. The results between PD and SD showed a close relation. There were no significant changes in electrical properties. So, it can be considered that the field-aged insulators are sound for the present.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.3
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• pp.73-80
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• 1999

The objective of this study were to investigate the properties and to improve the disadvantages of the polymer concrete such as brittle fracture, large hardening shrinkage . In this paper, steel fiber reinforced polymer concrete is prepared with various steel fiber aspect ratios(ι/d), contents(vol.%), and their material characteristics were investigated experimentally . The aspect ration (ι/d) of the steel fiber was reversly proportional to slump value, and slump value tended to decrease as increase of steel fiber content . And harding shrinkage and impact resistance tended to be improved as the steel fiber content and aspect ration were increased.

• Journal of Sensor Science and Technology
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• v.30 no.1
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• pp.51-55
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• 2021

We demonstrated a polymer dielectric with low leakage characteristics through an optimal blade coating method for low-cost and large-scale fabrication of metal-insulator-metal (MIM) capacitors. Cross-linked poly(4-vinylphenol) (C-PVP), which is a typically used polymer dielectric, was coated on a 10 × 10 cm indium-tin-oxide (ITO) deposited glass substrate by changing the deposition temperature (TD) and coating velocity (VC) in the blade coating. During the blade coating, the thickness of the thin c-PVP varied depending on TD and VC owing to the 'Landau-Levich (LL) regime'. The c-PVP-dielectric-based MIM capacitor fabricated in this study showed the lowest leakage current characteristics (10-6 A/㎠ at 1.2 MV/㎠, annealing at 200 ℃) and uniform electrical characteristics when TD was 30 ℃ and VC was 5 mm/s. In addition, at TD = 30 ℃, stable leakage characteristics were confirmed when a different electric field was applied. These results are expected to positively contribute to applications with next-generation electronic devices.