• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.4
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• pp.152-158
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• 2018

PVT (Physical Vapor Transport) method has advantages in producing high quality, large scale wafers where many researches are being carried out to commercialize nitride semiconductors. However, complex process variables cause various defects when it had non-equilibrium growth conditions. Annealing process after crystal growth has been widely used to enhance the crystallinity. It is important to set appropriate temperature, pressure, and annealing time to improve crystallinity effectively. In this study, the effect of the annealing conditions on the crystalline structure variation of the AlN single crystal grown by PVT method was investigated with synchrotron whitebeam X-ray topography, electron backscattered diffraction (EBSD), and Rietveld refinement. X-ray topography analysis showed secondary phases, sub-grains, impurities including carbon inclusion in the single crystal before annealing. EBSD analyses identified that sub-grains with slightly tilted basal plane appeared and the overall number of grains increased after the annealing process. Rietveld refinement showed that the stress caused by the temperature gradient during the annealing process between top and bottom in the hot zone not only causes distortion of grains but also changes the lattice constant.

• Journal of Science of Art and Design
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• v.6
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• pp.81-99
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• 2004

For making something to use as a tool since the emergence of mankind, the initial pragmatic purpose has transformed into a new genre of art over time. Things defined like this have rooted in our culture as tradition so far. In the midst of today's various trends, a reflection of tradition and a modern search for tradition by re-creating it are much more needed. To any people in any time, a new trend would undeniably develop on the basis of its previous tradition in any form. The colors appearing in such artwork are also an expression of each people's unconscious potentiality as essential grounds for human aesthetic. The traditional Korean Bojaki, which was made out of women's pragmatic mind trying to recycle trashy pieces of cloth in the 19th century of Chosun Dynasty, appears as a symbolization of our nation's original form in unconsciousness. It includes Confucianism, Buddhism, Zen and the Yin-Yang and Five Elements thought, which have been together with naturalism. The five colors appearing in the Yin-Yang and Five Elements are the basis. Fourteen selected samples around the five colors seen in the color scheme of the Chosun era's Bojaki were measured and their color values were found by analyzing them based on HCV(Hue, Chroma, Value)of the five primary colors as well as the five secondary colors. After choosing a few colors with bare eyes close to traditional Primary Colors and Secondary Colors amongst 14 pieces of data which particularly used traditional Five Colors and examining them using spectrophotometer(JX777), the following conclusions were drawn. Comparing only colors in Primary Colors, the result was red 7.11R 4.59/10.69, blue 6.71PB 3.18/6.45, yellow 3.91Y 7.56/6.12, respectively. With regard to Secondary Colors, it was reported that red 7.96RP 5.42/10.3, blue 7.8B 5.16/5.53, green 8.03GY 6.05/4.34, yellow 2.73Y 7.47/4.07, purple 2.39RP 4.69/4.56, respectively. (diagram) As a result, the standard of Five Colors can be used in modern fiber color. There are differences in dyeing material, methods and kinds of fiber of that time, but women of Chosun Dynasty combined and made fabric which was circulated. Consequently, an applicable attribute of the aye-color values was considered.

• Journal of the Korean Geographical Society
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• v.40 no.5 s.110
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• pp.491-513
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• 2005

The Republic of Korea is planning to build the now Multi-functional Administrative city (NMAC). The purpose of this paper is to suggest the conceptual framework for this new city that relies on the Korean geomancy, oriental viewpoint on man and nature relationship, particularly in Korea. According to the Geomancy which could conceptualize the human-environment relationship in the site, the overall landscape image of the city could be symbolized by two flying crane with three Taegueks. In transforming the overall landscape image to urban form, two diamonds which means eternity and strength arises from the western spatial viewpoint, as means to protect and harmonize the human, land and mountain relationship in this site and the symbolic meaning of this site as generative and sacred place in Korean people's mind. On the one hand, through juxtaposing of the two diamonds a geometric structure shows up, on the other hand the main axis of the city could be established from two crane and three Taegueks. On the North-South axis from the core of the symbolic green axis, symbolic things will be located, and the administrative offices will be Placed on the East-West axis. Peripherals of the central axis also play a role in developing overall land use from image. The buildings and residents could be arranged and located according to undulations and this is based on the oriental theory of geomancy. We can build cultural amenities on the head part of the crane and on the core area.

• The Korean Journal of Ecology
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• v.26 no.5
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• pp.237-246
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• 2003

A mountain village is defined as that which is autogenously formed over at least 100 years and supported by agricultural yields and forest products and forest area portion of which is over 70% in Guidelines for the Comprehensive Development Planning of Mountain Village. Recently, concerns about management planning of the Green and Eco-Village causes researches related to the Mountain Village's economics, tourism attractiveness, experience programming and investigation of the ecosystem and environment based on the village area. This kind of eco-village project should be supported by ecological evaluation of its spatial structure. But there is rare research of the village spatial structure studied from the ecological viewpoint originally. The purpose of this study is to interpret the spatial structure of Korean mountain village on the landscape ecological paradigm. The paradigm components are patches, corridors, networks, and matrix which explain the land and spatial structure at landscape scale. For this purpose, we selected two case study areas- Sansu and Ajick villages in Gimje city, Jeonlabukdo. We interpreted and evaluated the spatial structure by three steps: (1) to clarify the existing land mosaic pattern by land use mapping (2) to estimate the pore size as development area in matrix (3) to investigate the funnel effect of patch shape. These landscape ecological steps and frameworks could be applied for the proper methodology as fundamentals of eco-village planning and design.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.539-547
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• 2019

Recently, the international community signed a climate change agreement to prevent global warming. Yet currently, the fossil fuels have been widely used in to supply building energy for cooling and heating. The Green Building certification (G-SEED), an energy efficiency rating for new or existing buildings requires that buildings meet certain conditions. Insulation is used as a building material to reduce the energy supply to buildings and to improve the thermal insulation, and it accounts for more than 90% of the total heat resistance provided by the building surface components that meet the energy-saving design standards of new buildings. In this investigation, a performance evaluation study was conducted through an experimental study by directly extracting the foam polystyrene insulation on-site during the remodeling of a building that was in the range of 22~38 years old. Through tests, it was found that the thermal conductivity of the extrusion method insulation (XPS) was reduced by 48% and the compressive strength of XPS decreased by 36% compared to KS M 3808, which is the initial quality standard. For bead method insulation (EPS) with a thickness of 50mm, the thermal conductivity, the compressive strength, and flexural failure load were similar to the initial quality standard. Therefore, in the calculation of the primary energy requirement per unit area per year, the performance of bead method insulation can be estimated simply by considering the thickness of the insulation, while a correction factor that considers its performance deterioration should be applied when extrusion method insulation is used.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.1
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• pp.20-27
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• 2012

The $NH_3$-SCR characteristics of $NO_X$ over a V-based catalyst are experimentally examined over a wide range of operating conditions, i.e., $170-590^{\circ}C$ and $30,000-50,000h^{-1}$, with a simulated diesel exhaust containing $NH_3$, NO, $NO_2$, $O_2$, $H_2O$, and $N_2$. The influences of the space velocity and oxygen concentration on the standard-SCR reaction are analyzed, and it is shown that the low space velocity and high oxygen concentration promote the SCR activity by ammonia. The best $deNO_X$ efficiency is obtained with a $NO_2/NO_X$ ratio of 0.5 because of an enhanced chemical activity induced by the fast-SCR reaction, while at the $NO_2/NO_X$ ratios above 0.5 the $deNO_x$ activity decreases due to the slow-SCR reaction. The oxidation of ammonia begins to take place at about $300^{\circ}C$ and the reaction products, such as $N_2$, NO, $NO_2$, $N_2O$, and $H_2O$, are produced by the undesirable oxidation reactions of ammonia, particularly at high temperatures above $450^{\circ}C$. Also, $NO_2$ decomposes to NO and $O_2$ at temperatures above $240^{\circ}C$. Therefore, $NO_2$ decomposition and ammonia oxidation reactions deteriorate significantly the SCR catalytic activity at high temperatures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.4177-4185
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• 2012

LEDs are becoming the most suitable candidate replacing traditional fluorescent lamps because of its eco-friendly characteristics. LEDs are also actively used to design green building system and to make outdoor billboard as a back-light system due to its high energy efficiency. In this paper, we have developed AC direct driver for $12{\times}12$ FLB(flexible LED board) and LED flat light without SMPS. It has LID-PC-R101B driver IC that can support the high power factor and be composed of LED switching circuit in group. Also, an elaborate system designs can guarantee a high luminous efficiency, a high reliability and a low power consumption. The proposed FLB has the ultra slim shape of $450{\times}450$ mm, width of 4 mm and weight of 280 g. In the end, we have developed a prototype of FLB for billboard and flat light for room lighting with AC direct driver iposrder to verify the performance of the proposed system.

• Journal of Korean Society of Transportation
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• v.32 no.3
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• pp.187-197
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• 2014

The objective of this study is to analyze the travel behaviors of customers accessing to three different types of shopping facilities - traditional markets(TM), hyper markets(HM), and super supermarkets(SSM) - and also to find out the most desirable location for each type of shopping facilities that encourage sustainable transportation and smart urban growth. It also demonstrates what mode has the highest percentage of modal split and what is the access distance for public transport mode by each shopping facilities (SSM: 84.5% walking and 667m, TM: 20.1% bus and 1.6km, HM : 46.2% private car and 4.2km). Among TM, HM, and SSM, statistically significant differences are found in terms of mode choices and other associated travel behaviors. The research findings are expected to contribute to finding future urban planning and transportation solutions that promote walking and public transit uses for shopping trips and thus help support green transportation and sustainable urban growth.

• Steel and Composite Structures
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• v.34 no.5
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• pp.681-698
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• 2020

The paper addresses contribution to the modeling and optimization of major machinability parameters (cutting force, surface roughness, and tool wear) in finish dry hard turning (FDHT) for machinability evaluation of hardened AISI grade die steel D₃ with PVD-TiN coated (Al₂O₃-TiCN) mixed ceramic tool insert. The turning trials are performed based on Taguchi's L₁₈ orthogonal array design of experiments for the development of regression model as well as adequate model prediction by considering tool approach angle, nose radius, cutting speed, feed rate, and depth of cut as major machining parameters. The models or correlations are developed by employing multiple regression analysis (MRA). In addition, statistical technique (response surface methodology) followed by computational approaches (genetic algorithm and particle swarm optimization) have been employed for multiple response optimization. Thereafter, the effectiveness of proposed three (RSM, GA, PSO) optimization techniques are evaluated by confirmation test and subsequently the best optimization results have been used for estimation of energy consumption which includes savings of carbon footprint towards green machining and for tool life estimation followed by cost analysis to justify the economic feasibility of PVD-TiN coated Al₂O₃+TiCN mixed ceramic tool in FDHT operation. Finally, estimation of energy savings, economic analysis, and sustainability assessment are performed by employing carbon footprint analysis, Gilbert approach, and Pugh matrix, respectively. Novelty aspects, the present work: (i) contributes to practical industrial application of finish hard turning for the shaft and die makers to select the optimum cutting conditions in a range of hardness of 45-60 HRC, (ii) demonstrates the replacement of expensive, time-consuming conventional cylindrical grinding process and proposes the alternative of costlier CBN tool by utilizing ceramic tool in hard turning processes considering technological, economical and ecological aspects, which are helpful and efficient from industrial point of view, (iii) provides environment friendliness, cleaner production for machining of hardened steels, (iv) helps to improve the desirable machinability characteristics, and (v) serves as a knowledge for the development of a common language for sustainable manufacturing in both research field and industrial practice.

• Journal of the Korean Applied Science and Technology
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• v.2 no.1
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• pp.45-55
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• 1985

The present study was designed to investigate the effects of dietary fiber sources and levels on serum lipids in rats fed a hypercholesterol diet containing 0.5% cholesterol. Male Sprague-Dawley rats weighing 52.7 ${\pm}$ 7.27g were devided into sevel groups by completely randomized block design and fed various dietary fibers which were prepared from Rice bran, Siraegi (The dried green parts of a radish) and Bracken Fern at a level of 5% and 10% respectively. The results obtained in this study are summarized as follows: 1. Body weight gains were not significantly different among the groups and food intake was significantly higher in rats fed a diet of Siraegi 10% than those fed the control diet. 2. Fecal wet weights were significantly increased in all experimental groups. 3. Levels of serum total cholesterol in all experimental groups were significantly lower than that of the control group except the level in the R 10(Rice bran 10%) group. 4. Free Cholesterol levels in the serum were increased in all experimental groups, especially the levels in the R 10 (Rice bran 10%) and S 10 (Siraegi 10%) groups were significantly higher than that of the control group. 5. Ester Cholesterol levels in the serum were significantly lower in rats fed the experimental diets than those fed the control diet. 6. There was a tendency of higher serum HDL-Cholesterol levels in R5 (Rice bran 5%), R10 (Rice bran 10%) and B5(Bracken 5%) groups compared to the control group however no significant differences were found between the control group and all the experimental groups except in the case of the S5 (Siraegi 5%) group. 7. LDL, VLDL-Cholesterol levels in the serum sere significantly reduced in the S5 (Siraegi 5%), B5 (Bracken 5%) and B10 (Bracken 10%) groups. 8. The HDL-C./Total-C. Ratio was increased in all experimental group especially the Ratios in the S5 and B5 groups were significantly higher than that of the control group.