• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.8
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• pp.305-310
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• 2016

A thermal storage systems was designed to correspond to the temporal or quantitative variation in the thermal energy demand, and most of its heat is stored using the latent and sensible heat of the heat storage material. The heat storage method using latent heat has a very complex phenomenon for heat transfer and thermal behavior because it is accompanied by a phase change in the course of heating/cooling of the heat storage material. Therefore, many studies have been conducted to produce an experimentally accessible as well as numerical approach to confirm the heat transfer and thermal behavior of phase change materials. The purpose of this study was to investigate the problems encountered during the actual heat transfer from an internal storage tank through simulation of the process of storing and utilizing thermal energy from the thermal storage tank containing charged PCM. This study used analysis methods to investigate the heat transfer characteristics of the PCM with simultaneous heating/cooling conditions in the rectangular space simulating the thermal storage tank. A numerical analysis was carried out in a state considering natural convection using the ANSYS FLUENT(R) program. The result indicates that the slope of the liquid-solid interface in the analysis field changed according to the temperature difference between the heating surface and cooling surface.

• Journal of the Korea Furniture Society
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• v.20 no.3
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• pp.213-221
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• 2009

This study aimed at developing furniture for children by Ilgumte which is an expert manufacturer of educational equipments for school and kindergarten and the aim of this investigation is to develop the child-oriented furniture in consideration of Ilgumte's characteristic as a company composed of the disabled people, and furthermore to create a new sales market by developing own technology to improve competitive power. The current status of the child furniture in domestic and international market was researched and design concept on basis of this analysis was set, and through the designing process the new items of furniture having characteristics as follows were developed. First, the simple production way for the disabled to be able to work was selected and plywood used mainly by Ilgumte was presented as main material. Second, moving course, space and storage function were maximum considered, so that children feel convenient at using the furniture in their space, in case of playing as well as leaning. Third, natural wooden texture was mostly reflected for the emotional aspects of children and pink color played a role as partial accents. Finally, difficult production skill and expensive material were excluded for cost down.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.70-73
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• 2014

We have designed high performance flexible prism light-guide plate (LGP) in 5 inch TFT-LCD for mobile applications. We adopted novel material such as methacrylate and butyl acrylate mixture, as it called KURARITY. It has good flexibility by addition of butyl acrylate. And it has also good transmissivity because methacrylate is a major compound. Then, we achieved good test result to embody high brightness and flexible BLU in case of LGP of base and upper surface with 5 inch, thickness 1.5mm adding prism construct, it is superior brightness improvement than previous flexible LGP. It shows significant improvement than previous printing form about some 5% and in this course to flexible embody actual material it succeeded prism LGP production by 5 inch injection form process.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.1
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• pp.27-37
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• 2013

CFCs (Chlorofluorocarbons) and HCFCs (Hydrochlorofluorocarbons) that are chemically stable were proven to be a greenhouse gases that can destroy ozone layer. On the other hand, HFCs (Hydrofluorocarbons) was developed as an alternative refrigerant for them, but HFCs still have a relatively higher radiative forcing, resulting in a large Global Warming Potential (GWP) of 1,300. Current regulations prohibit production and use of these chemicals. In addition, obligatory removal of existing material is in progress. Methods for the decomposition of these material can be listed as thermal cracking, catalytic decomposition and plasma process. This study reports the development of low cost and high efficiency plasma scrubber. Stability of steam plasma generation and effect of plasma parameters such as frequency of power supply and reactor geometry have been investigated in the course of the development. Method for effective removal of by-product also has been investigated. In this study, elongated rotating arc was proven to be efficient in decomposition of HFCs above 99% and to be able to generate stable steam plasma with steam contents of about 20%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.166-167
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• 2006

Dendrimers represent a new class of synthetic macromolecules characterized by a regularly branched treelike structure. Multiple branching yields a large number of chain ends that distinguish dendrimers from conventional star-like polymers and microgels. The azobenzene dendrimer is one of the dendrimeric macromolecules that include the azo-group exhibiting a photochromic character. Due to the presence of the charge transfer element of the azo-group and its rod-shaped structure, these compounds are expected to have potential interest in electronics and photoelectronics, especially in nonlinear optics. In the present paper, we give pressure stimulation to organic thin films and detect the induced displacement current. Functional photoisometrization organic molecular the photo-stimulus to organic monomolecular L-films and LB films of dendrimer and 8A5H were performed. The 8A5H organic monolayer in case of pressure stimulus occurred that positive course but in case of the photo-stimulus compared positive and negative. It is assumed that generation forms of displacement current were measured when photo-stimulus for Impression.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1142-1145
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• 2004

ZnO surge arresters continuously endure the operating voltages during the operation course, and in the mean time, which need to withstand occasionally transient voltages of lightning and switching overvoltages. Under these voltages, the ZnO varistors inside arresters would have aging phenomena, one important result of aging phenomena is the increasing of resistive currents of varistors, which leads to the increasing of power losses of varistors. And the operating voltage is continuously applied on the ZnO varistors, there is a degradation phenomenon existing in ZnO varistors. When the degradation reaches a certain degree, then the arrester must stop operation. The degradation is related to the applied voltage ratio, the applied voltage ratio is high, the degradation is quickly. When the power loss is higher than the thermal dispersion ability of house of arrester, then the arrester will thermally breakdown. In this study the thermal stability characteristics of surge arresters for high power wil be discussed on the view point of watt losses and thermal breakdown.

• Journal of the Korean Society of Costume
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• v.38
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• pp.245-260
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• 1998

Our country's fur clothing industry has rapidly grown for a short time since it started with simple needlework of fur pieces, and now it is still developing as export industry that some enterprises besides general business firm export more than ten million dollars a year. However, it is true that fur clothing industry is still in unsatisfactory level in its size and system, compared with manufacturing or leather industry. Of course, we import crude material and processed fur on an entire base, and we have few wild fur on an entire base, and we have few wild fur animals because of our natural condition and it is hard to breed them. On the other hand, the world's fur industry shows that the demand of fur clothes is increasing as fur animal breeding is improved and developed and supply has become rather abundant with the help of fur clothing fashion since late 19th century : Also, there is a trend that some developed countries depend on importing rather than self-prodoction because of the character-istic of labor-concetntraled fur industry. Accordingly, considering this situation, we can expect fur clothing industry as promising export industry by analyzing the present situation of our country's fur clothing industry and suggesting its problems and solutions, and here are developing plans for growing fur clothing industry as promising export industry. First, smoothing delivery of crude material. Second, making high quality products and diversifying goods. Third, establishing effective competition system in fur clothing industry. Fourth, raising skilled man power. Lastly, there should be coopetation among the related fields in the aspect of policy including the support from the government.

• The Journal of the Korea Contents Association
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• v.11 no.1
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• pp.448-457
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• 2011

In this study, the teaching material has been developed based on Polya's Problem Solving Techniques for preparing Korea Information Olympiad qualification and studying principle of computer. the basis of discrete mathematics and data structures were selected as the content of textbooks for students to learn computer programming principles. After the developed textbooks were applied to elementary school students of Science Gifted Education Center of J University, the result of study proves that textbook helps improve problem-solving ability using the testing tool restructured sample questions from previous test. We need guidebook and training course for teachers and realistic conditions for teaching the principles of computer.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.10 no.1
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• pp.125-134
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• 1990

In order to utilize coal ash, which we go to great expense to scrap, as subba se course material, this study attempts to examine the deformation characteristics of coal ash with the addition of some cement when repeated loads are applied. The material of coal ash is obtained from Young dong and Youngwol thermal power plant. The results are : Unconfined compression strength shows rectilineal increase in propotion to the cement addition ratio. Within the scope of repeated loads of experimental condition, modulus of elasticity tends to decrease while compression strength shows about 21% increase.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.100-103
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• 2003

The primary insulation system used in an oil-filled transformer is kraft paper, wood, porcelain and oil. Modern transformers use paper that is chemically treated to improve its tensile strength properties and resistance to aging caused by immersion in oil. But these insulation papers are mainly aged to thermal stress. Over the course of the insulation paper and oil's life it is exposed to high temperatures, oxygen and water. Its interaction with the steel of the tank and core plus the copper and aluminium of the windings will eventually cause the chemical properties of the oil to decay. High temperature have an effect on mechanical strength of cellulous paper using the layer insulation. We made two aging cell in which thermal aging tests of insulation papers and mineral oil are conducted. It is measured dielectric strength, number of acid, moisture, etc. of insulation paper and oil aged in the aging cells.