• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.10
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• pp.1688-1693
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• 2016

In this study shall investigate the influence upon the electrical property of transformer oil due to the heat among accelerated heat degradation experiment for a constant hour in the typical insulation oils of mineral base oil, silicon base oil and vegetable oil. In addition, the electric insulation performance of insulation materials in transformer shall be evaluated through the electric property analysis according to the heat degradation of epoxy insulation material, which has been used for electric facilities such as a molded transformer.

• Journal of the Korea Furniture Society
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• v.15 no.1
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• pp.9-16
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• 2004

Five type boxes manufactured from cement(A), wood panel(B), charcoal-packed wood panel(C), plywood panel(D) and charcoal-packed plywood panel(E) were prepared. Relationship of preservation characteristic of strawberry and relative humidity, and properties of thermal and sound insulations in the boxes were examined. During the experimental duration, relative humidity in the cement box was highest and lowest in the charcoal-packed wood panel box. Weight loss of strawberry was greatest in charcoal-packed wood panel box and very little in cement box. In the boxes with charcoal-packed wood panel box and very little in cement box. In the boxes with charcoal, strawberry was preserved for 10 days without getting mold, but in cement box it was covered with mold in 3 days. The charcoal-packed boxes showed higher thermal insulation property than the cement box. There were no significant differences in the property of sound insulation among the 5 type boxes. Consequently, it is suggested that charcoal-packed wood panels can be used for a better ecomaterial.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.657-660
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• 2009

The surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ cathode particle was modified by lanthanum based oxide to improve electrochemical property and thermal stability. The XRD pattern of surface layer was indexed with that of $La_4NiLiO_8$. The discharge capacity of modified electrode was higher than that of pristine sample, specially at fast charge-discharge rate and high cut-off voltage. In the DSC profile of the charged sample, the generation of heat by exothermic reaction was decreased by surface modification. Such enhancement may by attributed to the presence of stable lanthanum based oxide, which effectively suppressd the reaction between electrode and electrolyte on the surface of $Li[Ni_{0.8}Co_{0.15}Al_{0.05}]O_2$ electrode.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.849-852
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• 2006

The lightweight foamed concrete is superior to properties of insulation and light-weight because it is included in many inner pore. So, lightweight foamed concrete used to construction field that need to property of insulation. The property of insulation of lightweight foamed concrete is varied with density. Also, Density is varied with hardening matrix and pore rate. The purpose of the experiment is to know thermal properties of specimen according to the change of density when heating the specimen. As a result of this experiment, the higher density, the lower temperature of mold. this tendency isn't same as ordinary lightweight foamed concrete, and then density 0.9 is expressed most low temperature result also the discontinuity of shape of mold was efficient for the prevention of the temperature rise.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.713-716
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• 2006

The main purpose of this research was to enhance the durability in both the design and construction of dams. Especially, in case of rockfill dams, the durability of tunnel concrete in a concrete-faced rockfill dam(CFRD) is achieved by optimizing the fly ash replacement for cement and application of steel fiber. The effect on durability and thermal property corresponding to the increasing replacement of fly ash and application of steel fiber was evaluated, and the optimum value of fly ash replacement and steel fiber application was recommended. The results show that 15% of fly ash replacement and $20kg/m^3$ of steel fiber application was found to be an optimum level and demonstrated excellent performance in durability and thermal property.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.214-215
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• 2007

Int this paper, we studied the analysis on long-term durability and output power characteristics of PV modules by variation on local thermal property. Using 5 modules(80W), we measured the maximum output power change during the test period. And the optical transmittance of glass was compared with PV module's maximum power fluctuation. The external environment change effected contamination on the entire or local surface of module. This caused the local temperature variation of each solar cell on PV module. The specific analysis is shown in the following paper.

• Macromolecular Research
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• v.10 no.6
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• pp.365-368
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• 2002

Thermoplastic polyurethanes (TPUs) with different hard segment length has been prepared from a fixed molar ratio of poly(tetramethylene ether glycol), 4,4'-diphenylmethane diisocyanate, and 1,4-butanediol by different polymerization procedures. Results reveal that the on-set temperature of endotherms ( $T_{cc}$ ) due to the crystallization of hard segments by cooling the TPUs from melt and the peak temperature of endotherms due to the melting of hard segments ( $T_{mh}$ ) by heating the TPUs increased and levelled off with increasing the hard segment length of TPUs. It has also been observed that soft segment glass transition temperature ( $T_{gs}$ ) of TPU decreased slightly with increasing the hard segment length, which explains less mixing of soft segments and hard segments. In tensile measurement of TPUs, strain hardening is observed with increasing the hard segment length, which is attributed to the strain induced crystallization of soft segments.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.23-29
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• 2019

Thermally expandable microsphere and aerogel composite was prepared by chemical compositization. Microsphere can produce synergies with aerogel, especially an enhancement of mechanical property. Through condensation between sulfonated microsphere and hydrolyzed silica sol, chemically-connected composite aerogel could be prepared. The presence of hydroxyl group on the sulfonated microsphere was observed, which was the prime functional group of reaction with hydrolyzed silica sol. Silica aerogel-coated microsphere was confirmed through microstructure analysis. The presence of silicon-carbon absorption band and peaks from composite aerogel was observed, which proved the chemical bonding between them. A relatively low thermal conductivity value of $0.063W/m{\cdot}K$ was obtained.

• Proceedings of the Korea Contents Association Conference
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• 2003.05a
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• pp.291-297
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• 2003

With the development of information communication technology, the demands for various, profound and advanced information on science and technology and the necessity for establishing science and technology information infrastructure with the aim of future oriented industry are ever increasing. Advanced countries are providing material property DB as well as bibliographic DB though the Internet. Establishment and dissemination of bibliographic DB at domestic is properly settled but research on material property DB is much to be desired. Accordingly, development and research on material property DB to construct the information infrastructure in science and technology are highly necessary. In this study, we have developed superconducting materials property DB which is highly advanced industry field in future. We provide the thermal and mechanical, and superconducting property data for oxide superconductors, and the database is designed by bibliographic information, material information and material property information section.

• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.59-63
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• 2007

The CNTs are the most extensively studied material which are characterized by the complete property of matter, structure, and the large thermal conductivity (thermal conductivity of CNTs ~>2000W/mK vs. thermal conductivity of Aluminum ~> 204W/mK). Thus, they are successfully applied to the various fields. However, due to the strong agglomeration caused by the van der waal's force, their applications are limited. In the present study, a new method for CNTs dispersion was developed by using the mechanical dispersion, acid treatment, and then Cu was coated. This process produces CNTs/Cu nanocomposite powders, whereby the CNTs are homogeneously located within the Cu powders. The electrical properties of the CNTs/Cu nanocomposite were investigated.