• Conservation Science in Museum
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• v.17
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• pp.55-68
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• 2016

Conservation and research efforts are currently underway at the National Museum of Korea on a series of artifacts excavated from Tomb No. 9 at Seogam-ri nearly a century ago by an archaeology team from the institution's colonialera predecessor. Among these objects are a number of bronze and gilt bronze buttons. The present study explores the production techniques used in making such buttons. Both bronze and gilt bronze buttons are hemispherical in shape and are similar in external appearance. However, their shanks differ significantly in size and cross-sectional shape, some with a round cross-section while others are square. The buttons, first sorted into two groups by each type of shank, were further subdivided by size. Analysis of round shanks has found variations in design and location as well as in shank thickness. In addition, the location where round shanks attach to buttons are usually irregular in surface. Square shanks, on the other hand, are more uniform in design and location. The shanks are typically located on the backs of buttons and attach to a groove which ostensibly serves to mark the correct position. X-ray imaging has revealed that round shanks have thick borders made from metal rather than dirt or other material. The buttons themselves appear to been cast using lost-wax technique. The ways in which each shank attaches to its respective button varies based on its cross-sectional shape.

• Hwankyungkyoyuk
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• v.9 no.1
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• pp.39-57
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• 1996

All kinds of environmental problems are related to each local and geographical environment. For this reason, it is necessary for schools in each region to provide environmental education which suits the geographical character of their particular region. In order to provide solutions to the environmental problems of each school's geographic region, the goal of this research is as follows: 1. We can make students realize the relationship between the human race and the environment by teaching according to the environmental conditions in each local area. 2. By teaching students about the problems in their own local environment, we can increase their concern about the state of their local surroundings. 3. When teaching about the environment, it is useful to use educational material which suits the character of each local region. 4. Students' interest in environmental preservation can be aroused through extracurricular environmental activities. The ares concerned are Chonnam and Kwangju City, which are divided into urban, industrial, rural, coastal, and mountainous areas. The conclusion about considering environmental education in environmental school social studies is as follows: 1. Kwangju and Chonnam should be divided into five sections, each with similar geographical environments. This will be an improvement over the old uniform approach to environmental studies in which all regions were treated as being the same each region will now receive special attention. 2. It is necessary to maximize the efficient use of the Environmental Education Building. When Media, environmental data and special materials for environmental education are used effectively, teachers can lead class effectively and students will be more interested in the class. 3. We can detect the cause of pollution, increase interest in the environment and easily solve environmental problems by collecting and displaying environmental educational materials. 4. An environmental education corner could boost students' interest in environmental problems and could act as a kind of bridge between theoretical and practical education. 5. Media and environmental data must be specialized according to the geographic character of each region. In this way, we can expect to improve the quality of environmental education over the simplistic environmental education of previous years. 6. Students will become interested in the problems of the region in which they live through social studies, and primarily through the environmental curriculum. 7. We can prevent learning deficiencies by making a consistent teaching plan. The teaching and learning methods will be improved and the teachers will be proud of what they teach. 8. The purpose of the Education Procedure Content Analysis is to make teaching and learning concise and easy by systematizing environmental and related subjects. This can be done by adding an environmental unit to the geographic section of social studies. 9. Citizens' interest in their own residential environment can be increased through action by sustaining environmental preservation movements to local region people.

• The Journal of the Petrological Society of Korea
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• v.28 no.4
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• pp.227-236
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• 2019

Medium to coarse-grained biotite granodiorite was used to build the Standing Buddha Statue in the Gwanchoksa temple. An ancient document revealed the period and place of constructing the statue: it was made in the northwest of Mt. Banyasan and then moved eastward. Also, the comparison of standing Buddha statue and basement rock in terms of texture, magnetic susceptibility, and gamma spectrometer shows that they have similar characteristics, which is considered to be the same provenance rock. The damage caused by surface contaminants observed in the statue seems to be a combined effect of environmental factors and aging of the epoxy resin. After removal of the contaminants in 2007, the contamination has resumed, and continuous monitoring is necessary. Algal engraftment becomes faster when biological contamination occurs on the surface of stone cultural heritage. Since the secondary lichen growth forms a symbiosis with mold, it is necessary to observe the spatial and distributional changes. Also, the aging epoxy resin may cause secondary damage due to contaminants generated due to the determination of salts, and deterioration of bonding strength due to breaking out. Thus it is desirable to secure stability through proper conservation management.

• Food Science and Preservation
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• v.17 no.1
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• pp.91-99
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• 2010

Extraction and bleaching of citric acid- and pepsin-soluble collagens (ASC and PSC, respectively) from shark (Isurus oxyrinchus) skin and muscle were investigated. The optimal sodium hydroxide concentration for extraction was 0.3 M and the optimal treatment time for removal of foreign material was 9 h. The optimal sodium hypochlorite level for bleaching of shark skin was 0.48% (w/v), and sodium hypochlorite was a better bleaching agent than acetone, hydrogen peroxide (10%, v/v), sodium sulfite (0.48%, w/v), sodium thiosulfate (0.48%, w/v), or sodium metabisulfite (0.48%, w/v). Optimal citric acid concentration and extraction time for ASC were 0.3 M and 72 h, respectively, whereas optimal conditions for extraction of PSC were treatment with 0.1 M citric acid containing 0.1% (w/v) pepsin for 24 h. Protein contents in ASSC (acid-soluble shark skin collagen), ASMC (acid-soluble shark meat collagen), PSSC (pepsin-soluble shark skin collagen), and PSMC (pepsin-soluble shark meat collagen) were 88.66%, 83.09%, 90.33%, and 84.81% (on a dry weight basis), respectively, similar to that of commercial marine collagen (88.86%). Net collagen contents of ASSC, ASMC, PSSC, and PSMC, calculated from hydroxyproline levels, were 70.31%, 25.70%, 83.09%, and 32.94%, respectively. The yields of freeze-dried ASSC, ASMC, PSSC,and PSMC were 57.22%, 53.85%, 23.28%, and 20.61%.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.2
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• pp.36-43
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• 2012

Objective of this study was to investigate the effects of pre-treatment of rice straw by sizes(3cm, milled), temperatures($35^{\circ}C\;and\;55^{\circ}C$), with/without NaOH treatment, and RPM on the characteristics of volatile fatty acids production. The concentration of total volatile fatty acids (TVFAs) was increased with the hydrolyzed time. Concentration of VFAs in milled rice straw was higher than that in 3 cm cut. With the alkali treatment, the concentration of TVFAs were sharply increased, which showed 3 times higher than non-treatment. Concentration of VFAs was high at 150 rpm at $35^{\circ}C$, and at 80rpm and 200 rpm at $55^{\circ}C$. Among them acetic acid was dominant, which showed the similar increase with TVFAs. It was also observed that in the case of fibrous material, the contents of cellulose and hemi-cellulose were reduced a little, but no change in lignin.

• Composites Research
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• v.26 no.5
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• pp.289-294
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• 2013

A thinner is used to improve the multi-walled carbon nano-tube (CNT) and carbon black (CB) dispersion in a polymer matrix and to make a soft electrode. The electrical and mechanical properties of the soft electrodes are investigated as functions of CNT, CB and thinner content. The optimal mixing condition for the electrode is thinner 80, CNT 3.5, CB 18 (phr) on the basis of matrix (KE-12). The specific resistance of that is 73 (${\Omega}{\cdot}cm$), and tensile strength, tensile modulus, and elongation of that is 0.45 MPa, 0.21 MPa, and 184%, respectively. Also, a simple structure of the actuator with an optimized electrode and elastomer is fabricated and its characteristic is evaluated. At the operating voltage 25 kV, the displacement of an elastomer KE-12 is 2.24 mm, and that of an elastomer KE-12 with thinner 50 (phr) is 4.05 mm. It shows a higher displacement compared to that of 3M 4910 which has similar modulus. The actuator made with elastomer and electrode of the same material (KE-12) may have advantages for fatigue life and application.

• Membrane Journal
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• v.25 no.1
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• pp.75-83
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• 2015

In this study, chlorophylls were been extracted from common local plants, deposited on polypropylene (PP) substrate using various approaches, and the oxygen generation effect of the chlorophylls were investigated. The loading of chlorophylls on the substrates was achieved by dipping and spraying methods, where the spraying coating showed overall better results regarding oxygen generation from the combustion experiments in the closed vessel or in the isolated vacuum oven cell than those of dip coating. In addition, a composite substrate was prepared by nylon6/6 nanofiber on the PP substrate, and it exhibited an increase in the activation of chlorophylls. In the case of samples containing titanium dioxide ($TiO_2$), the reaching time of oxygen concentration from 16% to 21% and the combustion test using a candle for a sample with 50% chlorophylls showed similar results to those of a sample without $TiO_2$. As such, combining a spray coating and $TiO_2$ incorporation into gas separation membrane systems are expected to be useful to understand the fundamentals of material properties for their applications as oxygen generation membranes and air filtration systems.

• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.181-191
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• 2007

The gemological charateristics of Gwangdong tektites and Baikdusan obsidians were investigated, using microscopy, density and refractive index measurements, X-ray fluorescence spectrometry, Inductively Coupled Plasma Mass spectrometry, X-ray powder diffraction, and electron microprobe analysis. The Gwangdong tektites and Baikdusan obsidians are both black in colour and slightly trans-lucent with various shades of brown when cut into a few mm thick. Both the materials yield conchoidal fracture on broken surface. The tektites occur as tear-drop shapes, ranging from 4 to 10 cm long, and in spheres, from 3 to 5 cm in diameter. On the surface numerous shallow pits up to 3 mm in diameter are present. Mohs' hardness and specific gravity are 5 to 5.5 and 2.66, respectively. The tektites are singly refractive, with an refractive index of 1.51. Numerous spherical air bubbles are randomly scattered throughout the tektites, and silica-rich glass inclusions are occasionally seen. X-ray powder diffraction analysis verifies that they are non-crystalline. The Baikdusan obsidians show very similar properties to those of the Gwangdong tektites, especially in hardness, amorphous nature and fracture. Nevertheless, the Baikdusan obsidian can readily be distinguished from the Gwangdong tektites by refractive index ($1.49{\sim}1.50$), specific gravity (2.67 to 2.68), and inclusions (absence of bubbles and presence of sanidine and magnetite crystals).

• Maxillofacial Plastic and Reconstructive Surgery
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• v.41
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• pp.52.1-52.8
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• 2019

Background: A compact passive oxide layer can grow on tantalum (Ta). It has been reported that this oxide layer can facilitate bone ingrowth in vivo though the development of bone-like apatite, which promotes hard and soft tissue adhesion. Thus, Ta surface treatment on facial implant materials may improve the tissue response, which could result in less fibrotic encapsulation and make the implant more stable on the bone surface. The purposes of this study were to verify whether surface treatment of facial implant materials using Ta can improve the biohistobiological response and to determine the possibility of potential clinical applications. Methods: Two different and commonly used implant materials, silicone and expanded polytetrafluoroethylene (ePTFE), were treated via Ta ion implantation using a Ta sputtering gun. Ta-treated samples were compared with untreated samples using in vitro and in vivo evaluations. Osteoblast (MG-63) and fibroblast (NIH3T3) cell viability with the Ta-treated implant material was assessed, and the tissue response was observed by placing the implants over the rat calvarium (n = 48) for two different lengths of time. Foreign body and inflammatory reactions were observed, and soft tissue thickness between the calvarium and the implant as well as the bone response was measured. Results: The treatment of facial implant materials using Ta showed a tendency toward increased fibroblast and osteoblast viability, although this result was not statistically significant. During the in vivo study, both Ta-treated and untreated implants showed similar foreign body reactions. However, the Ta-treated implant materials (silicone and ePTFE) showed a tendency toward better histological features: lower soft tissue thickness between the implant and the underlying calvarium as well as an increase in new bone activity. Conclusion: Ta surface treatment using ion implantation on silicone and ePTFE facial implant materials showed the possibility of reducing soft tissue intervention between the calvarium and the implant to make the implant more stable on the bone surface. Although no statistically significant improvement was observed, Ta treatment revealed a tendency toward an improved biohistological response of silicone and ePTFE facial implants. Conclusively, tantalum treatment is beneficial and has the potential for clinical applications.

• Journal of the Korean Arthroscopy Society
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• v.4 no.1
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• pp.7-12
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• 2000

Purpose : The purpose of this study is to evaluate the clinical outcomes and radiological changes after reconstruction of anterior cruciate ligament with human allograft. Material and Method : Authors analyzed 22 cases of anterior cruciate ligament allograft reconstruction which were done from January, 1995 to December, 1998 and could be followed up for a year or more. All cases were followed and reviewed in terms of anterior drawer test, Lachman test, Pivot shift test, radiographic examination, knee range of motion, and side-to-side difference of anteroior tibial translation using CA-4000 knee motion analyzer, and Lysholm knee scoring system. Result : The mean Lysholm knee score was 54 preoperatively and improved to 81 postoperatively by average of 27. The side-to-side difference of anterior tibial translation using CA-4000 knee motion analyser was less than 3 mm in 16 cases$(73\%)$, between 3 and 5 mm in 4 cases$(18\%)$, and greater than 6 min in 2 cases$(9\%)$. Average tibial tunnel enlargement was 1.5 mm, but there were not any osteoiysis or cystic formation along the tunnel and no relationship between tunnel enlargement and clinical outcome. Conclusion : Although this study had limited cases, clinical results of anterior cruciate allograft reconstruction were similar to those of reconstruction with autograft reported in the literatures. We think that allograft is an acceptable substitute fer autograft in anterior cruciate ligament reconstruction.