• Conservation Science in Museum
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• v.26
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• pp.161-182
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• 2021

A jungwangu, a type of medium-sized mortar, is a firearm with a barrel and a bowl-shaped projectileloading component. A bigyeokjincheonroe (bombshell) or a danseok (stone ball) could be used as a projectile. According to the Hwaposik eonhae (Korean Translation of the Method of Production and Use of Artillery, 1635) by Yi Seo, mortars were classified into four types according to its size: large, medium, small, or extra-small. A total of three mortars from the Joseon period have survived, including one large mortar (Treasure No. 857) and two medium versions (Treasure Nos. 858 and 859). In this study, the production method for medium mortars was investigated based on scientific analysis of the two extant medium mortars, respectively housed in the Jinju National Museum (Treasure No. 858) and the Korea Naval Academy Museum (Treasure No. 859). Since only two medium mortars remain in Korea, detailed specifications were compared between them based on precise 3D scanning information of the items, and the measurements were compared with the figures in relevant records from the period. According to the investigation, the two mortars showed only a minute difference in overall size but their weight differed by 5,507 grams. In particular, the location of the wick hole and the length of the handle were distinct. The extant medium mortars are highly similar to the specifications listed in the Hwaposik eonhae. The composition of the medium mortars was analyzed and compared with other bronze gunpowder weapons. The surface composition analysis showed that the medium mortars were made of a ternary alloy of Cu-Sn-Pb with average respective proportions of (wt%) 85.24, 10.16, and 2.98. The material composition of the medium mortars was very similar to the average composition of the small gun from the Joseon period analyzed in previous research. It also showed a similarity with that of bronze gun-metal from medieval Europe. The casting technique was investigated based on a casting defect on the surface and the CT image. Judging by the mold line on the side, it appears that they were made in a piece-mold wherein the mold was halved and using a vertical design with molten metal poured through the end of the chamber and the muzzle was at the bottom. Chaplets, an auxiliary device that fixed the mold and the core to the barrel wall, were identified, which may have been applied to maintain the uniformity of the barrel wall. While the two medium mortars (Treasure Nos. 858 and 859) are highly similar to each other in appearance, considering the difference in the arrangement of the chaplets between the two items it is likely that a different mold design was used for each item.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.1
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• pp.29-36
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• 2010

Ultrasonic inspection of heavy walled cast austenitic stainless steel(CASS)welds is very difficult due to complex and coarse grained structure of CASS material. The large size of anisotropic grain strongly affects the propagation of ultrasound by severe attenuation, change in velocity, and scattering of ultrasonic energy. therefore, the signal patterns originated from flaws can be difficult to distinguish from scattered signals. To improve detection and sizing capability of ID connected defect for heavy walled CASS piping welds, the low frequency segmented TRL Pulse Echo and Phased Array probe has been developed. The experimental studies have been performed using CASS pipe mock-up block containing artificial reflectors(ID connected EDM notch). The automatic pulse echo and phase array technique is applied the detection and the length sizing of the ID connected artificial reflectors and the results for detection and sizing has been compared respectively. The goal of this study is to assess a newly developed ultrasonic probe to improve the detection ability and the sizing of the crack in coarse-grained CASS components.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.8
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• pp.1709-1718
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• 2002

It is well recognized that improving capacity of positive grid in battery is one of key factors for controlling the expected long lift-time of Battery Energy Storage System(B.E.S.S). Thus it is really important to characterized material properties of positive grid which are mainly affected by fabrication process. In this study, two kinds of positive grids, which were fabricated by gravity casting and die-casting technique were used. Micro-structural observation and tensile test were conducted to investigate the effect of fabrication process of positive grid. Ultrasonic measurement based on pulse-echo method and ultrasonic C-scan technique also performed to correlate ultrasonic velocity with porosity ratio in positive grid. It was found that the porosity ratio of grid fabricated by gravity casting technique increased significantly compared to the grid fabricated by die-casting technique. It was also shown that ulrasonic technique is effective to evaluate the porosity ratio in positive grid.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.45-46
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• 2021

본 논문에서는 제조산업의 제품 품질검사의 자동화를 위한 딥러닝 기법을 제안하고 모델의 성능 최적화를 위한 특징 추출 필터의 크기를 비교한다. 이미지 특징을 자동 추출할 수 있는 CNN을 사용하여 전문인력 없이 제품의 표면 결함을 검출하고 제품의 적합성을 판단할 수 있는 이미지 처리 알고리즘을 구축하고 산업 현장에 적용하기 위한 검증 지표로 검출 정확도와 연산속도를 측정하여 결함 검출 알고리즘의 성능을 확인한다. 또한 연산량에 따른 성능 비교를 위해 필터의 크기에 따른 CNN의 성능을 비교하여 결함 검출 알고리즘의 성능을 최적화한다. 본 논문에서는 커널의 크기를 다르게 적용했을 때 빠른 연산으로 높은 정확도의 검출 결과를 얻었다.

• Archives of design research
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• v.14 no.3
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• pp.197-210
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• 2001

There are symbolicity and special meaning in the materials which are supposed to be used metalcraft from ancient to present. These are basical resources of hermeneutics and play a role as moaning elements. Generally, the precious Cold and Silver are mainly to be used with precious stone. But recently, ordinary materials like glass iron aluminum has begun to be used with them. Several artists are intentionally using them, and special skills which could be revealed by only the matherials are developing by them. In these skill, there are original material's texture and character of matter are looking like other matter. Well, special skills are adapted in these matters to magnify the possibility of expression, the originally codified meaning resources are disturbed. For example, The metal craft artist June Schwarcz is using the skills of electroforming, copper foiling, enameling, wire brush patina, fine wires fusing, etc. He is doing abstract forming and making various textures. And his works are very big size, and done by the skills of painting and sculpture. The outer form is very structural, special touches of the artists are heterogeneously mixed with the symbolic abstract expressionism color field. Further, there are mixed with Primitive original life atmosphere, Medieval ornamental aspect, Minimal, and Chaotic aspects. The meaning particles of these aspects are directly/indirectly joined but special skills and basic material languages are mixed together, the originally codified material language are disturbed. These disturbed material languages are becoming optically special effect and be illusion. It is making expressing way of tile metalcraft more fertile and be infinite.

• Journal of Conservation Science
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• v.29 no.3
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• pp.231-241
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• 2013

Analysis of the bronze bodhisattva from Pangyo-dong sites in Seongnam by computed tomography, ICP-AES, metallurgical microscope and SEM-EDS had to know manufacturing technique. And the origin of the raw material, was investigated using TIMS. Results with computed tomography, two bronze bodhisattva produced by lost-wax casting technique with hollow inside and could see the core of the inside. Result of component analysis and microstructure observation, material is alloy of copper-tin-lead and made by casting without artificial treatment. According to lead isotope ratio analysis result of bronze bodhisattva could be made into galena of the Gyeonggi massif in Korea South.

• Journal of Conservation Science
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• v.26 no.3
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• pp.269-276
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• 2010

This study aims to extract manufacturing techniques by analysing metallurgical characteristics of the cast-iron pot from Bubjusa, examining corrosion status and microstructure with a optical microscope, SEM-EDS, micro vickers hardness tester and XRD. The microstructure analysis has presented that ferrite and partial portion of pearlite exist within the corroded outer layer. The analysis of the inner layer revealed that there is pearlite and graphite of feather shape. The one of the middle layer, which is placed between outer and inner layer, showed that corrosion has been heavily developed. Micro vickers hardness values range from 217Hv to 698Hv in constituent layers and such values lie within the ranges of the ancient iron relics. The result of EDS analysis for each microstructure presented that the outer layer has been more decarbonized than the inner layer. XRD analysis of iron corrosion compound revealed that Goethite and Hematite had been produced from the corrosive process of iron. The study concludes that the large iron pot was made by casting technique, and microstructure of inner layer had a gray cast iron. Outer layer has been decarbonized through repetitive process of heating and cooling. This results can be used as fundamental data for comparative study to reveal manufacturing techniques of large cast-iron pot.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.28 no.4
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• pp.144-153
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• 2010

In making gardens, garden designers establish a principle using specific colors, collect materials, and combine them with their own aesthetic senses. This study is design mothed through the species and characteristics of flowering plants used in the Barrington court created by Gertrude Jekyll and Sissinghurst's white garden created by Vita Sackville-West, both of which are the most renowned gardens that used the white color. The analysis of each individual plant used in the gardens will be based on the season, colors, shapes, plant heights and aromaticity. Through their gardens, how the flowering plants aesthetically united with each other in creating the white gardens will be reviewed. To represent the freshness of spring, Jekyll planted Campanula spp. and Lilium spp. in the garden. Vita Sackvill-West aims at the moonlight in a summer night and features Delphinium spp., Rosa mulliganii, and R. longicuspis. The color of the flowers is in white, varying from pure white, ivory and silver. To prevent monotony due to monocolor flowers, the forms of the flowers are intense. To make white flowers look better, the colors of leaves include light green, light gray and bright and greenish yellow. Overall, cool colors are used to give a mystique, coolness, cleanness and to produce an fascinating and plaintive atmosphere, getting joined with white flowers and reflected light in the night. The White Garden has made significance in the history of landscape architecture: it was the starting point of garden design through theme colors, based on the idea and technology of planting design methods that discover the potential of colors and withdraw limits. And it also made a significant contribution to the advancement of garden art with combinations by aesthetic principles.

• Conservation Science in Museum
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• v.8
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• pp.49-69
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• 2007

This is about the scientific analysis of the 10 items of the gilt-bronze Panbul excavated from Anapji, Gyeongju. First, the composition of the Panbul was confirmed, using X-ray fluorescence spectrometer (XRF), and the patinas covering the surface of the Panbul were analyzed, using X-ray diffractometer (XRD). And the micro structures and gilt layer of the Panbul were investigated, using microscope and scanning electron microscope with energy dispersive spectrometer (SEM/EDS), and in order to investigate the internal conditions of the Panbul, X-radiography was conducted. As the result, it is found out that the material of the Panbul excavated from Anapji was the bronze of copper (86~95%) and tin (4~12%), and coated with gold. And cuprite (Cu₂O) was detected from red patina of the gilt-bronze Panbul, and chalcocite(Cu₂S) also was detected from the black patina. As the result of the observation of the micro structure through microscope, it is estimated that it was manufactured, using the wax molding method, and, judging from the fact that the thickness of gilt layer was not even, and that the groove had been filled, it was presumed that the amalgam coating method had been used, but some questions still remain, because mercury was not detected. Lastly, through the X-radiography, it was observed that the tiny round spots existed, which was presumed to have been generated during the casting.

• Korean Journal of Heritage: History & Science
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• v.49 no.2
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• pp.172-189
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• 2016

In this research, literature research on the Odong material, mixture ratio, casting method and casting facility was conducted on contemporary documents, such as Cheongong Geamul. Also, a long sword was produced using the Odong inlay technique. The sword reproduction steps were as follows; Odong alloying, silver soldering alloying, Odong plate and Silver plate production, hilt and sheath production, metal frame and decorative elements, such as a Dugup (metal frame), production, Odong inlay assembly and final assembly. For the Odong alloy production, the mixture ratio of the true Odong, which has copper and gold ratio of 20:1, was used. This is traditional ratio for high quality product according to $17^{th}$ century metallurgy instruction manual. The silver soldering alloy was produced with silver and brass(Cu 7 : Zn 3) ratio of 5:1 for inlay purpose and 5:2 ratio for simple welding purpose. The true Odong alloy laminated with silver plate was used to produce hilt and sheath. The alloy went through annealing and forging steps to make it into 0.6 mm thick plate and its backing layer, which is a silver plate, had the matching thickness. After the two plates were adhered, the laminated plate went through annealing, forging, engraving, silver inlaying, shaping, silver welding, finishing and polishing steps. During the Odong colouring process, its red surface turns black by induced corrosion and different hues can be achieved depending on its quality. To accomplish the silver inlay Odong techniques, a Hanji saturated with thirty day old urine is wrapped around a hilt and sheath material, then it is left at warm room temperature for two to three hours. The Odong's surface will turn black when silver inlay remains unchanged. Various scientific analysis were conducted to study composition of recreated Odong panel, silver soldering, silver plate and the colouring agent on Odong's surface. The recreated Odong had average out at Cu 95.57 wt% Au 4.16wt% and Cu 98.04 wt% Au 1.95wt%, when documented ratio in the old record is Cu 95wt% and Au 5wt%. The recreated Odong was prone to surface breakage during manufacturing process unlike material made with composition ratio written in the old record. On the silver plate of the silver and Odong laminate, 100wt% Ag was detected and between the two layers Cu, Ag and Au were detected. This proves that the adhesion between the two layers was successfully achieved. The silver soldering had varied composition of Ag depending on the location. This shows uneven composition of the silver welding. A large quantities of S, that was not initially present, was detected on the surface of the black Odong. This indicates that presence of S has influence on Odong colour. Additional study on the chromaticity, additional chemical compounds and its restoration are needed for the further understanding of the origin of Odong colour. The result of Odong alloy testing and recreation, Odong silver inlay long sword production, scientific analysis of the Odong black colouring agent will form an important foundation of knowledge for conservation of Odong artifact.