• 대한가정학회지
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• 제44권1호
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• pp.131-138
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• 2006

The yanggwan is a striped headpiece for civil and military officials worn with jebok, a costume for the royal ancestral worship ceremony, or jobok, a ceremonial costume for the courtier. It was called a jegwan when it was worn with a jebok. The geumgwan and jegwan are of the same style but the geumgwan has a gilded band and backside and the jegwan is mostly lacquered. The yanggwan was worn first with the jebok by the officials, both of which were received from the Chinese Ming dynasty in the 19th year of the King Gongmin's reign during the Goryeo period. The royal crown and court clothing system was two grades lower than the standard clothing code of the Ming dynasty of China. In the Joseon dynasty, the oyanggwan worn by the highest grade officials had five-stripes but was later replaced during the Daehan Empire by the seven-striped chilyanggwan used by Ming dynasty officials. Oyanggwans make up the majority of the surviving examples of these headpieces, with the exception of the six-striped yukyanggwan of Chung In-hak (1839-1919), the Minister of Justice, which originated in the Daehan Empire and whose owner is definitively known. The gilt portion of this yukyanggwan is finely engraved in relief with a bird, flower and tendril motif. The yukyanggwan is topped by a decorative bird ornament, called a jeongkkot. EDSS spectrum analysis of the gold plating reveals a composition of 51.32% gold and 10.34% silver. The yanggwan is composed of bamboo, mulberry paper and silk crepe. The black portions are lacquered. The individual yang is made with twisted mulberry paper.

• 박물관보존과학
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• 제16권
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• pp.46-55
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• 2015

신라시대 고분인 교동, 황남대총 북분, 금관총, 천마총, 금령총, 서봉총에서 출토된 금관 6점의 합금비를 분석하여 고분별로 성분비를 비교하였다. 분석결과 신라 금관 6점은 모두 금과 은으로 합금되어 있고 입식 금판의 순도는 교동 89.2wt%, 황남대총 북분 86.2wt%, 금관총 85.4wt%, 천마총 83.5wt%, 금령총 82.8wt%, 서봉총 80.3wt% 순으로 함량이 낮아지는 것이 확인되었다. 또한 금관의 순도와 금관 형식에 따른 편년을 비교해 보면 금관 중에서 가장 고식(古式)인 교동 금관의 순도가 가장 높고, 5세기 중후반에 축조된 황남대총과 금관총의 순도는 교동 금관보다 낮으며 5세기 말에서 6세기 초의 천마총, 금령총, 서봉총 금관의 순도가 가장 낮았다. 즉 빠른 시기의 고분일수록 금관의 순도가 높은 경향을 나타내었다.

• 대한치과보철학회지
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• 제19권1호
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• pp.17-27
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• 1981

This study was conducted to determine the chemical composition and the mechanical properties of four commercially available low gold-based crown and bridge alloy produced in Korea. Four dental casting gold-silver-palladium alloys, i.e., A, B, C and D (code of alloys) were selected for the evaluation of chemical composition, ultimate tensile strength, elongation. values and Vickers hardness. The chemical composition of test specimens was analyzed by both emission spectrography and wet gravitation method with a 1.5gm of low gold ingot. The tensile properties and Vickers hardness was determined with cast specimens treated in following three conditions; as-cast, softening heat treatment and hardening heat treatment. The tensile testing bars were cast in accordance with the model designed by Gettleman and Harrison (1969) which was modified from the A. D. A. Specification No. 14 for dental chromium-cobalt casting alloy. Nine tensile test specimens were made from a split silicone mold for each of the test alloys to the size of 2.5mm in diameter and a gauge length of 10mm. All four alloys were handled in accordance with conventional methods used in Type III gold alloys. Ultimate tensile strength and elongation were measured on an Instron Universal Tensile Testing Machine (Model 1125, Japan) operated at a crosshead rate of 0.1cm/min. Elongation values were measured using Digital Measuring Microscope (MS-152, FUSOH, Japan). Vickers hardness was determined with a Vickers Hardness Tester (Model VKH-l, Japan) at a 1.0kg load on a mounted tensile test specimen. The following results were obtained from this study; 1. All tested alloys were composed of Au, Ag, Pd, Cu, Zn and Fe in common. The composition rate of gold for all four alloys was found in the range of $42{\sim}47$ weight % as shown below. Alloy A; Au 45%, Ag 40.2%, Pd 5.76%, others 9.04%. Alloy B; Au 47.1%, Ag 29.03%, Pd 6.98%, others 16.92%. Alloy C; Au 45%, .Ag 26.9%, Pd 6.83%, others 21.07%. Alloy D; Au 41.8%, Ag 34.4%, Pd 6.95%, others 16.85%. 3. The ultimate tensile strength of the four alloys was in the range of $31{\sim}82kg/mm^2$. The test results were shown in the below order from the highest value; As-cast condition; D, B, C, A. Softening heat treament; B, C, D, A. Hardening heat treatment; D, B, C, A. 4. The test :results of the elongation rate for each alloy were in the range of $0.5{\sim}18%$. The test results were shown in the below order from the highest value; As-cast condition; A, D, B, C. Softening heat treatment; A, C, D, B. Hardening heat treatment; C, D, B, A. 5. Vickers hardness for each of the four alloys was in the range of $120{\sim}230$. The test results were shown in the below order from the highest value; As-cast condition; C, B, D, A Softening heat treatment; D, B, C, A. Hardening heat treatment; D, A, C, B. 6. There were no differences in the physical properties between as-cast condition and softening heat treatment.

• 대한치과보철학회지
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• 제41권3호
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• pp.369-378
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• 2003

Statement of Problem: Recently, resin cements have become more widely used and have been accepted as prominent luting cements. Current resin cements exhibit less microleakage than conventional luting cements. However, the constant contact with water and exposure to occlusal forces increase microleakage even in resin cements inevitably. Most bonding resins have been modified to contain a hydrophilic resin such as 2-hydroxyethylmethacrylate (HEMA) to overcome some of the problems associated with the hydrophobic nature of bonding resins. By virtue of these modifications, bonding resins absorb a significant amount of water, and there may also be significant stresses at bonding interfaces, which may adversely affect the longevity of restorations. Therefore the reinforcement of water stability of resin cement is indispensable in future study. Purpose: This study was conducted to examine the influence of water retention on microleakage of two resin cements over the period of 6 months. Materials and Methods: 32 extracted human teeth were used to test the microleakage of a single full veneer crown. Two resin cements with different components and adhesive properties - Panavia F (Kuraray Co., Osaka, Japan) and Super-Bond C&B (Sun Medical Co., Kyoto, Japan)- were investigated. The storage medium was the physiological saline solution changed every week for 1 month, 3 months, and 6 months. One group was tested after storage for 1 day. At the end of the each storage period, all specimens were exposed to thermocycling from $5^{\circ}C$ to $55^{\circ}C$ of 500 cycles and chewing simulation of 50,000 cycles, and then stained with 50% silver nitrate solution. The linear penetration of microleakage was measured using a stereoscopic microscope at ${\times}40$ magnification and a digital traveling micrometer with an accuracy of ${\pm}3{\mu}m$. Values were analyzed using two-way ANOVA test, Duncan's multiple range tests (DMRT). Results : Statistically significant difference of microleakage was shown in the 3-month group compared with the1-day or 1-month group in both systems (p<0.05) and there were statistically significant differences in microleakage between the 3-month group and the 6-month group in both systems (p<0.05). The two systems showed different tendency in the course of increased microleakage during 3 months. In Panavia F, microleakage increased slowly throughout the periods. In Super-Bond C&B, there was no significant increase of microleakage for 1 month, but there was statistically significant increase of microleakage for the next 2 months. For the mean microleakage for each period, in the 3-month group, microleakage of Super-Bond C&B was significantly greater than that of Panavia F. On the other hand, in the 6-month group, microleakage of Panavia F was significantly greater than that of Super-Bond C&B (p<0.05). Conclusion: Within the limitation of this study, water retention of two different bonding systems influence microleakage of resin cements. Further studies with the longer observation periods in viro are required in order to investigate water stability and the bonding durability of the resin cement. CLINICAL IMPLICATIONS Microleakage at the Cement-tooth interfaces did not necessarily result in the failure of the crowns. But it is considered to be a major factor influening the longerity of restorations. Further clinical approaches for decreasing the amount of microleakage are required.