• Title/Summary/Keyword: 금속직접조형

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Development of Direct Metal Tooling (DMT) Process for Injection Mold Core with Curved Conformal Cooling Channel (곡선형 형상적응형 냉각채널을 갖는 금형 코어 제작을 위한 DMT 공정개발)

  • Han, Ji Su;Yu, Man Jun;Lee, Min Gyu;Lee, Yoon Sun;Kim, Woo-Sung;Lee, Ho Jin;Kim, Da Hye;Sung, Ji Hyun;Cha, Kyoung Je
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.11
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    • pp.103-108
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    • 2019
  • The cooling rate and the uniformity of mold temperature, in the injection molding process, possess great influences on the productivity and quality of replications. The conformal cooling channel, which is of a uniform spacing from the mold cavity by the metal additive manufacturing process, receives much attention recently. The purpose of this study is to develop a mold core with a curved conformal cooling channel for a pottery-shaped thick-wall cosmetic container through the hybrid method of direct metal tooling (DMT) process. In this study, we design a mold core that contains the curved cooling channel for the container. A method that divides the cavity is proposed and the DMT process is carried out to form the curved cooling channel. The test mold core, with the curved conformal cooling channel, has been fabricated by the proposed method to confirm the feasibility of the design concept. We show that no leakage is observed for the additive manufactured test mold core, and its physical properties demonstrate that it can be sufficiently used as the injection mold core.

Sovereignty and Wine Vessels: The Feast Culture of the Goryeo Court and the Symbolic Meaning of Celadon Wine Vessels (고려 왕실의 연례 문화와 청자 주기(酒器)의 상징적 의미: 왕권과 주기(酒器))

  • Kim Yun-jeong
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.104
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    • pp.40-69
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    • 2023
  • This paper examines the relationship between celadon wine vessels and royal banquets by focusing on their unique forms. It explores the symbolism in their forms and designs and the changes that took place in the composition of these vessels. By examining the royal annals in Goryeosa (The History of the Goryeo Dynasty), the relation of celadon wine vessels and royal banquets is examined in terms of the number of banquets held in the respective reigns of the Goryeo kings, the number of banquets held by type, and the purpose of holding them. A royal banquet was a means of strengthening the royal authority by reinforcing the hierarchy and building bonds between the king and his vassals. It was also an act of ruling that demonstrated the king's authority and power through praise of his achievements and virtues. Royal banquets were held most often during the reigns of King Yejong (r. 1105-1122), King Uijong (r. 1146-1170), King Chungnyeol (r. 1274-1308), and King Gongmin (r. 1351-1374). Particular attention is paid here to the changes in the types and forms of celadon wine vessels that occurred starting in the reigns of King Yejong and King Chungnyeol, which is also the period in which the number of royal banquets increased and royal banquet culture evolved. The king and his subjects prayed for the king's longevity at royal banquets and celebrated peaceful reigns by drinking and performing various related acts. Thus, the visual symbolism of vessels for holding, pouring, or receiving alcohol were emphasized. Since the manner of drinking at a banquet was exchanges of pouring and receiving alcohol between the king and his subjects, the design of the ewers and cups had a significant visual impact on attendees. It can be seen, therefore, that decorating wine vessels with Daoist motifs such as the immortals, luan (a mythological bird), turtle dragons, fish dragons, and gourd bottles or with Confucian designs like hibiscus roots was intended as a visual manifestation of the purpose of royal banquets, which was to celebrate the king and to pray for both loyalty and immortality. In particular, the Peach Offering Dance (獻仙桃) and Music for Returning to the Royal Palace (還宮樂), which correspond to the form and design of celadon wine vessels, was examined. The lyrics of the banquet music embodied wishes for the king's longevity, immortality, and eternal youth as well as for the prosperity of the royal court and a peaceful reign. These words are reflected in wine vessels such as the Celadon Taoist Figure-shaped Pitcher housed in the National Museum of Korea and the Bird Shaped Ewer with Daoist Priest in the Art Institute of Chicago. It is important to note that only Goryeo celadon wine vessels reflect this facet of royal banquet culture in their shape and design. The composition of wine vessel sets changed depending on the theme of the banquet and the types of liquor. After Goryeo Korea was incorporated into the Mongol Empire, new alcoholic beverages were introduced, resulting in changes in banquet culture such as the uses and composition of wine vessel sets. From the reign of King Chungnyeol (r. 1274-1308), which was under the authority of the Yuan imperial court, royal banquets began to be co-hosted by kings and princesses, Mongolian-style banquets like boerzhayan (孛兒扎宴) were held, and attendees donned the tall headdress called gugu worn by Mongol women. During the reign of King Chungnyeol, the banquet culture changed 132 banquets were held. This implies that the court tried to strengthen its authority by royal marriage with the Yuan court, which augmented the number of banquets. At these banquets, new alcoholic drinks were introduced such as grape wine, dongnak (湩酪), and distilled liquor. New wine vessels included stem cups, pear-shaped bottles (yuhuchunping), yi (匜), and cups with a dragon head. The new celadon wine vessels were all modeled after metal wares that were used in the Yuan court or in the Khanates. The changes in the celadon wine vessels of the late Goryeo era were examined here in a more specific manner than in previous studies by expanding the samples for the study to the Eurasian khanates. With the influx of new types of wine vessels, it was natural for the sets and uses of Goryeo celadon wine vessels to change in response. The new styles of celadon wine vessels linked the Goryeo court with the distant Khanates of the Mongol Empire. This paper is the beginning of a new study that examines the uses of Goryeo celadon by illuminating the relations between royal banquets and these unique celadon wine vessels that are stylistically different from everyday vessels. It is to be hoped that more studies will be conducted from diverse perspectives exploring both the usage of Goryeo celadon vessels and their users.

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Analysis of Particle Laden Flow and Erosion Rate Around Turbine Cascade (터빈 익렬 주위에서의 부유입자 유동 및 마모량 해석)

  • 김완식;조형희
    • Journal of the Korean Society of Propulsion Engineers
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    • v.2 no.2
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    • pp.14-23
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    • 1998
  • The present study investigates numerically particle laden flow through compressor cascade. In general, a lot of turbine engines are affected by various particles which are suspending in the atmosphere. Especially in the case of aircraft aviating in volcanic, industrial and desert region including many particles, each components of engine system are damaged severely. That damage modes are erosion of compressor binding and rotor path components, partial or total blockage of cooling passage and engine control system degradation.. Initial damages can not be serious but cumulation of damages influences on safety of aircraft control and economical maintenance cost of engine system can be increased. When dust, materials and volcanic particles in the atmosphere flow in the compressor, it is necessary to predict damaged and deposited region of compressor blades. To the various flow inlet angle, predictions of particles trajectory in compressor cascade by Lagrangian method are presented and impulses by impaction of particles at blade surface are calculated. By the definition of particle deposition efficiency, characteristics of particles impact are considered quantitatively. With these prediction and experimental data, erosion rates are predicted for two materials - ceramic, soft metal - on compressor blade surface. Improvements like coating of blade surface could be found, by above prediction.

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