• 보존과학연구
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• s.19
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• pp.23-34
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• 1998

Bokam-ri site was excavated from July 1996 to September 1998 and archaeologically assumed to be grouped with tombs of Mahan period. Among these groups, Tomb No. 3 had built up with stone chamber and found one pair of gilted footware near the jar coffin. This footware was severely corroded and cracked so transfered it gently with soil. Radiography film of this footware showed spike decorations on the bottom and fish-shapped ornament. Gilted footware was consolidated with soil using Paraloid B72 10%~15%solution and cleaned using small tools and microscope. SV427 and HV427 as epoxy resin and Araldite(rapid type) used for joining and restoring. The fore part of gilted footware was connected with nails and folded “L” shape to introduce the bottom material. Tortoise-shell design and flower ornaments appeared on the surface and fish-shaped ornaments, spikes and spangles on the bottom. It was found that 7 spikes and 5 fish-shaped ornaments remained well. Especially, Fish-shaped ornaments were firstly found in the gilted footware and appraised archaeologically important materials.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.4
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• pp.147-155
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• 2019

In this study, flexural tests of granite reinforced with titanium metal rods were carried out to repair and restore the damaged stone-made cultural heritage, the Stone Pagoda of the Mireuksa Temple Site. A total of twelve specimens were tested. The primary test parameters are the reinforcement ratio and the location of the reinforcement. For restoration, epoxy resin was used for joining the separated stones, and titanium metal rods were used for structural reinforcement. Test results showed that the flexural failure took place in specimens with a reinforcement ratio of 0.8% or less, and shear failure occurred when the reinforcement ratio was 1.68% or more. The peak load of the reinforced stone was found to be highly related to the reinforcement ratio. The peak load increased with increasing the reinforcement ratio. Also, the flexural behaviors of the reinforced stones were affected by the location of the reinforcement. Based on the test results, this study recommends the reinforcement ratio of the reinforced granite to induce ductile behavior.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.18-24
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• 2021

Polymers, polymer compounds, are very moldable at low temperatures and have good strength against weight, and hence, are often used in the interior and exterior materials of cars. Owing to the increasing environmental problems, emission regulations have become stricter, which has increased the use of lightweight polymers as substitutes for metal materials. Therefore, as the use of polymer increases, extensive research is being conducted on the bonding technology of polymers, such as polyurethane and epoxy. However, the increased cost and environmental pollution by adhesives caused by the polymer manufacturing plant depend on the chemical composition or the manufacturer's mix ratio. To compensate for this issue, a laser beam is irradiated through a highly permeable polymer (PC) placed on top of an absorbent polymer (ABS) to transfer the laser output to the ABS polymer and fuse them at the interface. Moreover, enabling laser penetrating bonding by placing a stainless steel wire mesh between the two polymers can achieve improved bonding strength compared to conventional heterogeneous polymer bonding.

• Conservation Science in Museum
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• v.16
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• pp.122-137
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• 2015

White porcelain pitcher with an openwork dragon and cloud design across its surface in the collection of the National Museum of Korea (Deoksu 5531) was acquired in 1915. The restoration has been so far completed only for the mouth of the pitcher. This study discusses a new method based on 3D scanning and printing for the restoration of missing parts in the openwork dragon and cloud design. A strength test was performed on six output materials that have been already commercialized for comparison with the strength of materials used for traditional restoration such as epoxy putty (Quick Wood^®) and epoxy (Araldite AY103+HY956^®). This process confirmed that the digital technology-aided making of a restoration model requires less time and efforts than handmade work, all the while producing a more precise model. More importantly, this method being a non-contact method, it reduces risks associated with handmade work. Another advantage of this method is that digital pre-restoration images can be saved and used for future references. Notwithstanding, future research is needed on how to effectively apply digital technology for restoration of ancient objects and how to evaluate and use 3D output as well as on the method of shaping, joining and coloring the 3D output.

• Steel and Composite Structures
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• v.43 no.1
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• pp.19-30
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• 2022

The static strength and fatigue crack resistance of the aircraft skin structures depend on the materials used and joint type. Most of the commercial aircraft's skin panel structures are made from aluminium alloy and carbon fibre reinforced epoxy. In this study, the fatigue resistance of four joint configurations (metal/metal, metal/composite, composite/composite and composite/metal) with riveted, adhesive bonded, and hybrid joining techniques are investigated with experiments and finite element analysis. The fatigue tests were tension-tension because of the typical nature of the loads on aircraft skin panels susceptible of experimenting fatigue. Experiment results suggest that the fatigue life of hybrid joints is superior to adhesive bonded joints, and these in turn much better than conventional riveted joints. Thanks to the fact that, for hybrid joints, the adhesive bond provides better load distribution and ensures load-carrying capacity in the event of premature adhesive failure while rivets induce compressive residual stresses in the joint. Results from FE tool ABAQUS analysis for adhesive bonded and hybrid joints agrees with the experiments. From the analysis, the energy release rate for adhesive bonded joints is higher than that of hybrid joints in both opening (mode I) and shear direction (mode II). Most joints show higher energy release rate in mode II. This indicates that the joints experience fatigue crack in the shear direction, which is responsible for crack opening.

• Conservation Science in Museum
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• v.13
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• pp.1-11
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• 2012

While the project for registering the unregistered relics that had been stored in the relic storage warehouse was in progress, restoration operations were started for the large size pottery pieces that had been excavated from the Geumgangsa Temple Site and it is attempted to explain the pottery pieces and to introduce the process of the overall conservation treatment. About 600 pieces of large size pottery had been separately stored in more than 40 relic boxes in their original damaged condition without making it possible to figure out their shape, size, usage and quantity at all. Due to the enormous number and weight of the pottery pieces, they were, first of all, pre-classified largely into 6 groups of pottery pieces in consideration of the visible features such as pottery thickness, color sense and glaze brilliance, etc. for each kind of pottery raw material. However, as a result of making them adhere together on a temporary basis, they turned out to be only one piece of pottery in reality. In this restoring process, in order to see if the generally used cyanoacrylate adhesive was in fact safe when a very large, heavy and deformed pottery piece was to be put together, its safeness was checked by examining the adhesion velocity, adhesion strength and dissolution velocity for both from low to high viscosities through preliminary experiments. In order to restore the lost parts after putting the existing pieces together, diversified epoxy resins were used to fit their shapes. Considering that the bottom of the restored relic was shaped to be not flat but round without allowing it to stand alone, an exhibition mount was manufactured so that the relic could be stored stably and used readily for exhibition.

• Conservation Science in Museum
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• v.31
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• pp.71-103
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• 2024

The National Museum of Korea Conservation science division conducted a precise diagnosis and a non-destructive investigation to comprehensively assess the overall damage of the Twin-lion stone lantern from the Godalsa Temple site, Yeoju to be placed on display in the museum's outdoor stone garden, then reviewed the relevant conservation and management plan and applied conservation treatment to the artifact. The museum carried out the treatment in the following order: precise diagnosis; dismantling of the previously-restored part of the roof stone; reinforcement and restoration of the roof structure with new stone; restoration of the previously-restored part of the lantern's support stone (jungseok); surface texture treatment to the restored area; cleaning (basic, laser); and color matching. The previously-restored part of the roof stone was removed and restored with new stone material, based on the results of a safety diagnosis regarding the separation at the said part. Granite from the Sangju area was selected as the material for the restoration in consideration of the results of mineral analysis as well as the surface color and particle size. The new stone was divided into three pieces based on the descending edges of the octagonal roof structure and joined together using epoxy resin. The structure was further strengthened by inserting titanium rods. It is expected that the status diagnosis and conservation treatment of the twin-lion stone lantern from the Godalsa Temple site in Yeoju will be used as a reference for the future conservation and management of outdoor displays of stone cultural heritage.