• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.05a
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• pp.144-146
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• 1992

Surface acoustic wave(SAW) oscillator offers many attractive features for application to vapor sensors. The perturbation of SAW velocity by the hexafluoropropence plasma polymer thin film has been studied for relative humidity sensing. adsorption of moisture produces rapid aid changes in the properties of the film, resulting in a change in the velocity of surface acoustic waves and, hence, in the frequency of one SAW oscillator. The device used in our experiments have 55 MHZ SAW oscillator fabricated on a LiNbO substrate.

• Journal of the Korean Professional Engineers Association
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• v.43 no.5
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• pp.35-40
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• 2010

The world economy is threatened by rising oil prices due to the depletion of resources, and climatic changes are intensified due to rapid increase of greenhouse gases emission. Global warming is recognized as a worldwide problem not only as national level one, collaborative efforts are in progress actively. The fact is that the development of new & renewable energy which can replace fossil fuel and preserve the environment is the key of the attention in accordance with "low carbon, green growth" policy of our government. Biogas is an energy source. And the best part of using biogas is that wastes are treated in its production process.

• Journal of the Korea Furniture Society
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• v.23 no.2
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• pp.130-143
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• 2012

The rapid increase in apartments of Korea brought about overall changes in the life style, and definitely played the biggest role to convert into western style. Since 1960, furniture has been changed for 50 years along with apartments, but furniture companies and the academic world had insufficient historical materials and lack of study. In addition, considering the changing trend according to residents' life style, the data of furniture industries should be collected to study every year or in 5 years at least. Therefore, this study aims to provide basic data that gives historical materials or design clues based on recent AV equipment-oriented storage furniture in the living room that prioritized design in public space. Accordingly, the study looked into the periodical trends of Korean furniture industries, analyzed 10 furniture companies in Korea which is actively doing business as the sample and arranged key points of periodical changes of furniture in the table, and suggested the conclusion according to the image map, style, color, material, and function.

• Proceedings of the ESK Conference
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• 1998.04a
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• pp.194-199
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• 1998

The purpose of this study is conducted to evaluate the psycho-physiological effects of the dynamic lighting on VDT workers and to establish the dynamic lighting design guides. The main experimental factors are changes of illuminance. There were five conditions including 1) ripid change, 2) slow change at 300lx .approx. 500lx, 3) a static illuminance level at 300lx, and 4) rapid chante, 5) slow change at 200lx .approx. 300lx. The ranges of change were set typical illuminance level for the simple visual task requirement and reasonable to a VDT task ; 200-300-500lx. The psycho-physiological measurements used were EEG, R-R interval, CFF, near point accommodation, feeling perceived fatigue, and work performance. Analysis of psycho-physiological factors shows that higher illumination level conditions are more affirmative effects than lower on VDT workers under 500lx except for the results of feeling perceived fatigue. And about the speed of changes of illuminance level. The conditions of slow change were better than the others in terms of the work performance as well as psycho-physiological results.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.281-284
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• 2003

The microstructural changes of Al-Zn-Mg-Cu alloy containing Sc during hot extrusion and post heat treatment is investigated. Two kinds of Al-Sc alloys with different alloying elements (B1, B2) are hot extruded to make I-shape bars at 380$^{\circ}C$, then the bars are solution treated at 480$^{\circ}C$ for 2hrs followed by artificial aging at 120$^{\circ}C$ for 24hrs. The interior microstructure of as extruded bar consists of elongated grains, however, fine equiaxed grains are mainly observed around surface. The microstructural gradient suggests that different restoration process can proceed during the hot extrusion. For B1 and B2, different grain growth behaviors are found around the surface during the post heat treatment. Rapid grain growth behavior around the surface is discussed related with the crystallographic orientation of the grain.

• 한국디지털정책학회:학술대회논문집
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• 2004.11a
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• pp.283-294
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• 2004

Within the rapidly changing environment of global economics, the environment of higher education in the universities & companies, also, has been, encountering various changes. Popularization on higher education related to lifetime education system, putting emphasis on the productivity of education services and the acquisition of competitiveness through the market of open education, the breakdown of the ivory tower and the Multiversitization of universities & companies, importance of obtaining information in the universities & companies, and cooperation between domestic and oversea universities, industry and educational system must be acquired. Therefore, in order to adequately cope with these kinds of rapid changes in the education environment, operating E-Learning Education & company by utilizing various information technologies and its fixations such as Internet, E-mail. CD-ROMs. Interactive Video Networks (Video Conferencing, Video on Demand), CableTV etc., which has no time or location limitation, is needed.

• Applied Microscopy
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• v.24 no.1
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• pp.114-122
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• 1994

Drastic changes were observed in egg chamber during oogenesis of Aedes togoi immediately after blood meal. The egg chamber, in which the oocyte remains at previtellogenic stage before blood meal, shows very little change in size even for 3 days after emergence but increased 25 folds in volume within 60 hours after blood meal, presumably due to rapid yolk formation. Upto 6 hours after blood meal structures considered to be the precursor of the yolk granules were not observed in the space between follicle cells and oocyte. Vitelline bodies, which are similar to dense bodies secreted from follicle cells, appeared in the space at 10 hours after blood meal. Although vitelline bodies were fused to form vitelline layer, these bodies seem to contribute to the formation of yolk granules. Nurse cells are connected to oocytes by cytoplasmic bridge before blood meal, but the cells are absorbed into oocyte at 6 hours after blood meal.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.895-898
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• 2008

The mobility of water in set yogurt during fermentation was studied using nuclear magnetic resonance (NMR) relaxometry. The spin-spin relaxation was analyzed using a 2-fraction model, resulting in 2 spin-spin relaxation time constants $T_{21}$ and $T_{22}$. Both $T_{21}$ and $T_{22}$ exhibited rapid changes between 2 and 4 hr of fermentation, coinciding with the drop in pH and the rise in lactic acid bacteria count. The spin-lattice relaxation time $T_1$ increased over the fermentation period. Both $T_1$ and $T_2$ showed an increase in the mobility of water upon gel formation during fermentation. Water redistribution within the gel matrix due to casein aggregation and structure forming may be responsible for the changes in mobility.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11c
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• pp.593-599
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• 2000

Accurate quantification of plant physiological properties is often necessary for optimal control of an automated greenhouse production system. Conventional crop growth monitoring systems are usually burdensome, inaccurate, and harmful to crops. A thermal image analysis system was used to accomplish rapid and accurate measurements of physiological-property changes of water-stressed crops. Thermal images were obtained from several species of plants that were placed in a growth chamber. Analyzing the images provided the pattern of temperature changes in a leaf and the amount of differences in the temperature of stressed plants and non-stressed plants.

• Journal of Biosystems Engineering
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• v.24 no.5
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• pp.439-444
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• 1999

Automated greenhouse production systems often require crop growth monitoring involving accurate quantification of plant physiological properties. Conventional methods are usually burdensome, inaccurate, and harmful to crops. A thermal image analysis system can accomplish rapid and accurate measurements of physiological-property changes of stressed crops. In this research a thermal imaging system was used to measure the leaf-temperature changes of several crops according to water deficit. Thermal images were obtained from lettuce, cucumber, pepper, and chinese cabbage plants. Results showed that there were significant differences in the temperature of stressed plants and non-stressed plants. The temperature differences between these two group of plants were 0.7 to 3$^{\circ}C$ according to species.