• Proceedings of the IEEK Conference
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• 2000.06b
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• pp.76-79
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• 2000

The 3$\mu\textrm{m}$-thick PVDF (Polyvinyiidene fluoride) thin film have been prepared using physical vapor deposition with electric field, and its FT-IR specrum, dielectric property and electric conduction phenomenon have been investigated. Since the characteristic peaks ate detected at 509.45 and 1273.6〔cm〕 in the FT-IR spectrum, we are confirmed that the ${\beta}$ -phase is dominant in the PVDF thin film. In the results of dielectric properties, the PVDF thin film shows anomalous dispersion, i.e. gradual decrease of dielectric constant with increase of frequency, and also that the dielectric absorption point changes from 200Hz to 7000Hz with increasing temperature of thin film, which is consistent with the Debye's theory. The activation energy (ΔH) obtained from temperature dependence of dielectric loss is 21.64 ㎉/㏖. We confirm that the electric conduction mechanism of PVDF thin film is dominated by ionic conduction by investigating the dependence of the leakage current of the thin film on the temperature and the electric field.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.11
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• pp.721-726
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• 2015

In this study, the properties of C-V degradation for thermal conductivity silicone rubber sample which is attached by copper-copper, copper-aluminum, aluminum-aluminum on upper-side and under-side has been measured at temperature of $80^{\circ}C{\sim}140^{\circ}C$. The results of this study are as follows. In case the frequency is increased, it found that the electrostatic capacity increased with increasing temperature to $80^{\circ}C$, $110^{\circ}C$, $140^{\circ}C$ regardless of kind of electrode. It found that the electrostatic capacity increased with becoming high temperature range of frequency regardless of kind of electrode. This result is considered to be caused by thermal absorption on the thermal conductivity silicone rubber sample. It found that the electrostatic capacity decreased with increasing temperature and frequency. This result is considered to be caused by molecular motion of C-F radical or OH radical.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.4
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• pp.189-196
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• 2010

U-factor and solar heat gain coefficient(SHGC) usually can be used as the index to evaluate the thermal performance. U-factor is a concept for heat loss by the temperature difference between inside and outside, so it's useful to be applied in heating season. But SHGC that indicates the fraction of heat from incident solar radiation that flows through a window by means of optical transmission, as well as absorption, re-radiation and convection is for cooling season. In other words, U-factor and SHGC of windows by cities have to be reflected to select the window of the energy conservation. The purpose of this research is to analyze the energy use impacts by SHGCs of windows for detached house in Inchon and Ulsan through energy simulation by eQUEST.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.495-500
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• 2001

In this study, it was analized and examined fundamental properties of Electric Pole Recycled Aggregate(EPRA) and hardened properties & chemical resistance with H$_2$SO$_4$by replacement ratios of EPRA, and the results are as follows 1) In the case of electric pole recycled coarse aggregate, All fundamental properties are better than that of normal recycled aggregate and both water absorption and amount of crushed loss are with level of natural aggregate 2) As the replacement ratio of electric pole recycled fine aggregate is increased strength development is decreased. but in the case of coarse aggregate, that of it is with level of natural aggregate 3) As the replacement ratio of electric pole recycled fine aggregate is increased chemical resistance is decreased. but in the case of coarse aggregate, that of it is with level of natural aggregate

• International Journal of Concrete Structures and Materials
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• v.9 no.2
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• pp.145-158
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• 2015

The consequence of sulfate attack on geopolymer concrete, made from an alkali activated natural pozzolan (AANP) has been studied in this paper. Changes in the compressive strength, expansion and capillary water absorption of specimens have been investigated combined with phases determination by means of X-ray diffraction. At the end of present investigation which was to evaluate the performance of natural alumina silica based geopolymer concrete in sodium and magnesium sulfate solution, the loss of compressive strength and percentage of expansion of AANP concrete was recorded up to 19.4 % and 0.074, respectively.

• Parasites, Hosts and Diseases
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• v.51 no.6
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• pp.743-745
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• 2013

We compared the efficacy and applicability of a modified formalin-ether concentration technique (M-FECT) to the conventional FECT (C-FECT) and the agar plate culture (APC) method for the detection of Strongyloides stercoralis larvae. For this purpose, we used 600 human fecal specimens collected in an endemic area of southern Thailand. In the M-FECT, we used 2 layers of wire meshes, instead of gauze, to avoid the loss by absorption/adhesion of larvae to the gauze during filtration, and we reduced the exposure time of S. stercoralis larvae in stool samples to formalin. By such simple modifications, the efficacy of M-FECT has become comparable to APC and was much better than that of C-FECT for the diagnosis of strongyloidiasis.

• International Journal of Industrial Entomology and Biomaterials
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• v.24 no.1
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• pp.1-5
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• 2012

A newly developed silkworm variety, GoldenSilk makes bright yellow cocoon. In this article, the basic characteristics of GoldenSilk cocoon were examined through color analysis, degumming characteristics and UV spectrophotometer. The colorant of GoldenSilk cocoon was not distributed evenly throughout the cocoon layer but existed in the outer layer of the cocoon. The colorant has not good resistance against sunlight. The degumming loss percentage of GoldenSilk cocoon was 29.2%, which is relatively higher than that of the authorized one. UV spectrophotometer showed specific absorption band around 400 to 500 nm, which is the specific yellow colorant of the GoldenSilk cocoon extracted to the degumming solution during the degumming process.

• Journal of KSNVE
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• v.7 no.4
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• pp.621-629
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• 1997

For computer aided design and costruction of low noisy power plants, indoor and outdoor noise prediction program has been developed. The program utilizes the predefined data of noise sources and building materials and has the faculty to estimate the source level using the empirical formula in case of the measured data not being available. In the noise prediction, the mutual noise propagation between indoor and outdoor sites are considered. The outdoor noise source in the calculation of geometric divergence effects is modelled as the omni-directional finite line or planar source according to the source geometry and the receiving points. Outdoor noise prediction is carried out to consider the diffraction effect due to plant structures as well as the attenuation effect due to atmospheric absorption and soft ground. The results of indoor and outdoor noise prediction for a recently constructed diesel engine power plant show good agreement with the measured.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.04a
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• pp.164-169
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• 1995

Cracks in the concrete structure are known to develope by various mechani는, including an alkali-aggregate reaction. The alkali-silicate reaction between aggregates and cement is studied using polarized microscope, electron probe microanalyser and electron microscope. Metamorphosed, biaxial quartz and feldspars grains appear to have reacted readily with alkali from cement. For a given mineral, fine-grained minerals tend to react readily over the coarse-grained ones. A chemical analysis shows that the elements K, Na, Ca, and Si migrated, in most cases, fro the portion of h호 concentration to the low, Some clay minerals, including smectite and illite are newly formed as one of the reaction products. The continual expansion and shrinkage of the expandible clay minerals, probably due to repeated absorption and loss of water within the structure, plays an important role in the development of cracks within the concrete structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.604-607
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• 2004

Concrete structures in the marine environment often deteriorate in the early stage of their service life because of contact with various aggressive conditions. In recent years, the study on the concrete in the marine environment are carried out to increase their service life. In this experimental study, the concrete specimens were prepared with various adding contents of inorganic antifouling agent$(0\~3.0wt\%)$ composed to some fluosilicate solution. For evaluatin of the physical and chemical properties of concretes containing inorganic antifouling agent, various tests such as setting time, slump loss, compressive strength, water absorption rate, freezing and thawing resistance and SEM micrographs of concrete, were conducted. As the results, physical and chemical properties of concretes were improved with an adding of inorganic antifouling agent. From the results of various tests, the optimal adding contents of antifouling agent was $1.0wt\%$.