• Journal of Electrical Engineering and Technology
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• v.5 no.2
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• pp.342-351
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• 2010

The SiC-$ZrB_2$ composites were fabricated by combining 30, 35, 40, 45 and 50 vol. % of zirconium diboride ($ZrB_2$) powders with silicon carbide (SiC) matrix. The SiC-$ZrB_2$ composites and the sintered compacts were produced through spark plasma sintering (SPS) under argon atmosphere, and its physical, electrical, and mechanical properties were examined. Also, the thermal image analysis of the SiC-$ZrB_2$ composites was examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed via x-ray diffraction (XRD) analysis. The apparent porosity of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$, SiC+45vol.%$ZrB_2$ and SiC+50vol.%$ZrB_2$ composites were 7.2546, 0.8920, 0.6038, 1.0981, and 10.0108%, respectively. The XRD phase analysis of the sintered compacts demonstrated a high phase of SiC and $ZrB_2$. Among the $SiC+ZrB_2$ composites, the SiC+50vol.%$ZrB_2$ composite had the lowest flexural strength, 290.54MPa, the other composites had more than 980MPa flexural strength except the SiC+30vol.%$ZrB_2$ composite; the SiC+40vol.%$ZrB_2$ composite had the highest flexural strength, 1011.34MPa, at room temperature. The electrical properties of the SiC-$ZrB_2$ composites had positive temperature coefficient resistance (PTCR). The V-I characteristics of the SiC-$ZrB_2$ composites had a linear shape in the temperature range from room to $500^{\circ}C$. The electrical resistivities of the SiC+30vol.%$ZrB_2$, SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$ SiC+45vol.%$ZrB_2$ and SiC+50vol.%$ZrB_2$ composites were $4.573\times10^{-3}$, $1.554\times10^{-3}$, $9.365\times10^{-4}$, $6.999\times10^{-4}$, and $6.069\times10^{-4}\Omega{\cdot}cm$, respectively, at room temperature, and their resistance temperature coefficients were $1.896\times10^{-3}$, $3.064\times10^{-3}$, $3.169\times10^{-3}$, $3.097\times10^{-3}$, and $3.418\times10^{-3}/^{\circ}C$ in the temperature range from room to $500^{\circ}C$, respectively. Therefore, it is considered that among the sintered compacts the SiC+35vol.%$ZrB_2$, SiC+40vol.%$ZrB_2$ and SiC+45vol.%$ZrB_2$ composites containing the most outstanding mechanical properties as well as PTCR and V-I characteristics can be used as an energy friendly ceramic heater or ohmic-contact electrode material through SPS.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5
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• pp.113-121
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• 2010

Shumi-sen(須彌山), built by Nohjagong(路子工) in the southern garden of the Palace Garden during the Asuka Period, is understood as being Sumeru based on an Indian perspective of the theory of the origin of universe. It is also viewed as Mt. Myogoh from a Chinese Buddhist worldview. It is thought to be a type of assembled stone structure with Poong-ryoon (風輪)-Su-ryoon(水輪)-Geum-ryoon(金輪)-Ji-ryoon(地輪) carved into each of the 4 stone pieces. These building shapes are thought to have been utilized as stone for exterior construction as opposed to those structures built during the Shilla Period of China and Korea. Aside from Nohjagong's record of Shumi-sen, most of the records from Japan's period of the time suggest that Shumi-sen was an important element that played a role in the scenery of the seasonal outdoor gardens. It is also thought, from the sentences and expressions surrounding the records, that a combination of the seasonal sceneries was utilized centered on Shumi-sen, and that they were all used during festival events. From a perspective of analysis and interpretation dependent on the limited literature and on observation, it cannot be verified whether the Mt. Sumeru Stone(須彌山石) excavated from the Stone God Ruins is the same Shumi-sen that Nohjagong built along with Okyo(吳橋), but it is thought that the 'Shumi-sen type stone structure' that was later built repeatedly as part of the palace garden facilities is identical to the Shumi-sen built at the Imperial Palace's southern garden, or at least a re-built structure based on the Shumi-sen that Nohjagong built with stones and ponds used to create the foundation. Thus, Shumi-sen that Nohjagong supposedly built along with Okyo is suspected to be a figurative rock arrangement and, at the same time, a miniaturized scenic rock arrangement(縮景樹石) that maximized the shape of Buddhism's Shumi-sen. On the other hand, the surface pattern on Mt. Sumeru Stone is very similar to the multi -layers of mountainous pattern icons expressed in the patterns of the Great Golden Incense Burner(百濟金銅大香爐) or Mountain-Water Scenery Sculptural Brick(山水山景紋?) that were built during the Baekjae pcriod aod the rear side of Hwalsuk-jebul Basal Byungipsang(滑石諸佛菩薩竝立像); it is suspected that similar patterns would have been used if patterns were made on Shumi-sen that Nohjagong built. Also in consideration of the physical theory of MI. Sumeru Stone, the Siphon theory of using a pressure difference in water level was applied to the fountain facilities of Mt. Sumeru Stone that seemed to have been built from the practical rock arrangement perspective for the purpose of feasts, etc.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.2
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• pp.77-85
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• 2014

This study was conducted to examine the morphological characteristics of those Azalea Cultivars(hereinafter, Azalea Cultivars) that are mainly used for landscaping in Korea in order to prepare classification criteria. As testing materials, major Azalea Cultivars cultivated in large quantities by its producing companies were collected. Thereafter, the qualitative and quantitative characteristics of the traits of Azalea Cultivars were investigated in the way of characteristic investigation for new cultivars of azalea used by the Korea Seed and Variety Service in order to classify them and prepare the classification criteria. Since cultivar names have not been established for Azalea Cultivars for landscaping thus far, the data were compiled using the names used by cultivating companies. According to the results, Azalea Cultivars cultivated in Suncheon, Jeonnam mainly for landscaping were 10 in number; Beni, Daewang, Three, Zasanhong, Hancheol, Sancheoljuk, Gyeobsancheoljuk, Baekcheoljuk, Akado, and Seok-am. Among them, the cultivars Beni, Daewang, and Three could not be easily distinguished from each other because they are commonly called Yeongsanhong by cultivating companies and the shapes of their leaves and flowers are similar to each other. In particular, the flower color of Beni was 'bright red', that of Daewang was 'vivid purple', and that of Three was 'bright purple'. In addition, Zasanhong and Hancheol were similar to each other in shape the degree of expression of spots on the flowers and the gloss on the front side of the leaves of Hancheol were higher and stronger compared to that of Zasanhong. Sancheoljuk flowered in early April, earlier compared to other Azalea Cultivars. Gyeobsancheoljuk is an elementary species of Sancheoljuk and it had double flowers although all other traits were similar to those of Sancheoljuk. Although Baekcheoljuk was easily distinguished because it had white flowers, its leaves were similar to those of Akado the reason why these two cultivars could not be easily distinguished from each other. The cultivar Akado flowered early May later compared to other Azalea Cultivars and its flowers were relatively large in diameter as with Baekcheoljuk and Sancheoljuk. Finally, the cultivar Seok-am was easily distinguished because it had smaller leaves compared to other cultivars and it flowered late as with the cultivar Akado.

• Restorative Dentistry and Endodontics
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• v.36 no.4
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• pp.300-305
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• 2011

Objectives: The aim of this study was to evaluate the various NiTi rotary instruments regarding their ability to provide a circular apical preparation. Materials and Methods: 50 single canal roots were selected, cut at the cementodentinal junction and the coronal 1/3 of the canals was flared using Gates Glidden burs. Samples were randomly divided into 5 experimental groups of 10 each. In group I, GT files, Profile 04 and Quantec #9 and #10 files were used. In Group II Lightspeed was used instead of Quantec. In Group III, Orifice shaper, Profile .06 series and Lightspeed were used. In Group IV, Quantec #9 and #10 files were used instead of Lightspeed. In Group V, the GT file and the Profile .04 series were used to prepare the entire canal length. All tooth samples were cut at 1 mm, 3 mm and 5 mm from the apex and were examined under the microscope. Results: Groups II and III (Lightspeed) showed a more circular preparation in the apical 1mm samples than the groups that used Quantec (Group I & IV) or GT files and Profile .04 series.(Group V)(p < 0.05) There was no significant difference statistically among the apical 3, 5 mm samples. In 5 mm samples, most of the samples showed complete circularity and none of them showed irregular shape. Conclusions: Lightspeed showed circular preparation at apical 1 mm more frequently than other instruments used in this study. However only 35% of samples showed circularity even in the Lightspeed Group which were enlarged 3 ISO size from the initial apical binding file (IAF) size. So it must be considered that enlarging 3 ISO size isn't enough to make round preparation.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.389-396
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• 2008

The purpose of this study was to evaluate the color stability of resin cements with accelerated test. Four dual curing resin cements: Panavia-F (KURARAY). Duolink (BISCO), Variolink-II (Ivoclar Vivadent), and RelyX Unicem (3M ESPE) and 1 self curing resin cement: Resiment CE (j. l. Blosser) were used in this study. In control group, Gradia Anterior (GC) composite resin and Tescera Dentin (Bisco) indirect composite were used. Ten disk shape specimens were made from each resin cement. The specimens were subjected to an accelerated aging process in a refrigerated bath circulator at 60$^{\circ}C$ for 15 and 30 days. Spectrophotometric analyses were made before and after 15 days and 30 days of accelerated aging time. The color characteristics ($L^*,\;a^*,\;b^*$) and the color difference (${\Delta}E^*$) of the specimens before and after immersion were measured and computed. Regardless of type of the resin cements, $L^*$ value was decreased and $a^*$ value was increased, but there were no significant difference. But $b^*$ value was increased significantly (p < 0.05). Tescera inlay showed least color change (p < 0.05), but Gradia showed notable color change after 15 days. After 30 days on accelerated aging, ${\Delta}E^*$ value was increased (Panavia-F < Variolink-II < Resiment CE < Duolink < Unicem) (p < 0.05). but there were no significant difference among Panavia-F, Variolink-II, and Resiment CE groups. After 30 days of accelerated aging, ${\Delta}E^*$ value of all resin cements were greater than 3.0 and could be perceived by the human eye.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.4
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• pp.1-13
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• 2012

Landscape Garden tradition of excellent examples of places that are focused on hydroponics management. South Korea and China, this thing was noticeable among them South Korea which emphasizes the natural contours of the natural streams in accordance with the basic idea to use examples that feature will do. Gardens in China by constructing a flat terrain also naturally expect to find examples of conscious ideas depending on the water and the mountains are characterized. These differences and similarities through the Gardens of the tradition of separating the two countries to build their Garden by site Soswaewon and Zolzengwon appear in the target hand is to identify the characteristics between the director. Research methods literature survey, field survey of the natural environment through the plantation, background history, the people who intend to study, to configure the ground water space, Jian, construction and management has been studied in hydroponics. As a result, Damyang-gun, Jeollanam-do, South Korea in the Garden of the Soswaewon(瀟灑園) organization with inner garden and outer garden of a small, but the scale of production to Yang San-Bo's 'eunilgwan' implement security based rock mooring takes the form of a linear channel and the water came down from riding pending to avoid artifacts gathered again took the form of streams flowing into that. Hutton was a rubble pile structure Jian. Building an Gwangpunggak, Jewoldang, as Daebongdae consist, respectively, depending on the purpose of the mooring was deployed by focusing. The other hand, is located at Suzhou, Jiangsu of China Zolzengwon(拙政園) flat terrain is located on. Largely divided eastern gardens, Central Gardens and the Gardens of the West was conducted by five thirds of the total area of Water accounted for. Pavilion the center of the pond, Seokgasan achieve a variety of landscapes and architectural features that are most of the Ming. The two countries, each region's natural environment and human environment, different, unique characteristics to each other in the implementation of a unique hydroponic Garden tube and ideological backgrounds, but especially the 'eunilgwan' and the terrain that is divided according to the conditions of this study, so fulfilling Garden was conducted.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.30 no.4
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• pp.44-55
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• 2012

This study is to interpret how landscape aesthetic characteristics of moderation, which is the point of human-oriented neo-confucianism vision, are projected to the landscape organization of a Dodong-SeoWon, known for its overflow to neo-confucianism grounds and standards among domestic SeoWon. The aspects of neo-confucianism discussion in the shape of Dodong-SeoWon with the beauty of from and contents dominating the landscape of Dodong-SeoWon different from constructive completeness as 7 external and internal landscape organization including placement, circulation, setting, vista, fencing, naming, and decoration are as follows. The left direction of Dodong-SeoWon, part of external organization, is the result of landscape organization that emphasized the stage of moderation through the unification of man and nature by naturalizing natural direction to human-oriented directions. Important aspects to rule external orders and standards of Dodong-SeoWon are principles of one classes based on ranks and bilateral symmetry that is the unity of setting and circulation landscape organization from penetrating the spirit of moderation with no bias. By securing territoriality by fencing the unity of verticality and horizontality, the landscape organization to reach moderation is expressed. Meanwhile, Suwoloo(水月樓) perceived on the floor of central assembly hall, the formation of time frame from roof piles of Hwanjumun(喚主門) as well as pilars of Jungjeongdang(中正堂), and rime link method inducing visual balance and openness through segment, combination, and others are vista organization that show the ideality of unique neo-confucianism building. Also as part of landscape organization contents. semantically, building name including arrangement from Taegukdoseol, ideological naming following the name of Ssanggye-SeoWon, which is the former body, the name of the hall symbolizing the transfer of neo-confucianism enlightenment, impartiality with no bias, as well as Geoinjae(居仁齋) and Geoijae(居義齋) based on olympic, are also results of applying neo-confucianism standards. Additionally. the SeoHoe(瑞花) expressing the change of IleumIlyang(一陰一陽) on the stylobate of Jungjeongdang, Saeho(細虎) which goes up and down, as well as Simul made of four dragons, are artistic expression of the moderation that symbolizes the harmony of ying and yang with no exceeding or insufficiency. Humorous and unique rocks and stones evenly arranged in all spots of Dodong-SeoWon are to promote anti-strict organization by offsetting the image and external order of the lecture hall as strict as it is, and this is very ironic as it is the other landscape organization in different dimension as well as the expression of moderation.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.98-104
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• 2010

The objective of this study was to understand the origin and characteristics of stone tower's style through the study of the 'Village Shrine at Seoji-ri, Andong'. The three kinds of stone towers were located forming a line of 9m on the hill of a red pine forest along the stream in the village. Toward the direction looking at the village, the three-story stone located on left, the two-story stone located in the middle, and the common style stone tower located on right. The bottom part of the three-story stone was 2.5m in length, 1.8m in width, 1.3m in height. The bottom part of the two-story stone was 1.3m in length, 1.5m in width, 0.9m in height. The common style stone heap tower was 3.0m in diameter, 1.8m in height with a cone shape. The small hat-shaped stone was presumed to be the top part of a three-story stone. According to the three factors(heaven, earth, human) of the idea of the universe in Korea, most ancient remains have components of odd numbers. Then it had been substituted with smaller three-story stone(at present, two-story stone). And then altered to a common stone tower later, such as the 'Village Shrine at Seoji-ri, Andong' that shows the combination of the Bronze Age's megalithic and a folk religion. The 'Village Shrine at Seoji-ri, Andong' is a valuable relic that shows the stone towers, and is derived from the Bronze Age. The 'Village Shrine at Seoji-ri, Andong' shows that the 'Village Shrine at Seoji-ri, Andong' was embodied the three-factor(heaven, earth, human) idea of the universe in three-story stone of megalithic culture' remains.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.4
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• pp.1-13
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• 2010

This research was conducted to understand the characteristics and traits of Baekje's palace backyard by studying and analyzing the usage, shape, size, material, and place of origin of the odd-shaped stones found at the remains of Baekje's palace in Waggung-ri, Iksan. The results of the research are as following. The odd-shaped stones found at the Baekje palace backyard were used for two purposes. Some of the stones were used as heaping stones(疊石) for the stone waterfall in the backyard while others were used as ornamental stones(置石) to exhibit the uniqueness and beauty of the stone themselves. The stones used for the waterfall had various shapes and materials and were arranged to symbolize the beauty of natural scenery. On the other hand, the ornamental stones were used to exhibit their beauty of forms. Among the twenty six ornamental stones, four were large, four were mid-sized, and eighteen were small. The twenty four heaping stones used for the waterfall were all categorized as small. All of the stones were not too big, easily coming into sight of human beings. The heaping stones were mostly limestones, and some of them were metamorphic rocks such as marble, quartz, green rock, slaty rock, and phyllite. Almost all of the odd-shaped stones used for Baekje's palace backyard have beautiful patterns and specific forms that resemble natural scenes or animals such as a turtle, terrapin, pig, bear, or elephant. Some of the ornamental stones apparently went through carving to emphasize the unique shapes. Considering the usage and characteristic of the odd-shaped stones, one of the most characteristic feature of the Wanggung-ri palace backyard can be said to be 'the garden of odd-shaped stones'. Meanwhile, according to references, interviews, questionings, and on-the-spot surveys on the people who quarried the stones, the stones found at the remains of the Wanggung-ri palace came mostly from Mt. Cheonho in Hosan-ri, Yeosan-myeon, Iksna, and Mt. Shidae in Dosoon-ri, Wanggung-myeon.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.3
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• pp.29-38
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• 2010

A moat is a pond or waterway paved on the outside of a fortress that is one of the facilities to prevent enemy from approaching the fortress wall or classify it as the boundary space, and this study was undertaken to find out the characteristics of the moat that was existed in the East and the West from ancient time to medieval time with the following result. First, the moat in the East was installed of natural moat and artificial moat at the same time while the moat in the West had the fortress built in naturally advantageous site to use natural most substantially more. Second, the moats of Korea were smaller in scale compared to other countries (Japan, China and the Western countries). Third, the fortresses in the East were built to protect towns or royal palace while the West had the fortress to protect the residence of kings, lords, great wealthy persons and the like, and they were used jointly with the natural moat and artificial moat to defend against the infiltration of enemy. Fourth, the Pungsujiri in the Orient is one of the numerous ideologies forming the supplementary ideologic system of Korean people that could not be denied as the perception that influences on Korean people after the Silla Dynasty, and this Pungsujiri was considered when determining the location of the castle. The moat surrounding the castle had the role to keep the good energy in the castle from escaping away. Fifth, the Ha-Ha technique in the west was designed to prevent the external power from infiltration by digging the ditch on the place applicable to the boundary of the garden site, rather than the fence. While walking around along the water-side path without knowing the existence of this ditch, when the road is discovered with the cut off in the ditch, people had the exclamation without actually recognizing such astonishment. It was originally the dike for military purpose during the medieval time that was designed to look into the garden without physical boundary surrounded with the vertical fence in the garden that by having the deep ditch like shape on the boundary line of the garden which was designed to form the farm by preventing various types of cattle from coming inside the garden and bring in the garden element for farms, forestry, agricultural land and the like.