• Economic and Environmental Geology
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• v.56 no.6
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• pp.715-728
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• 2023

Tracksite of pterosaurs, birds, and dinosaurs in Chungmugong-dong in Jinju was designated as a natural monument in 2011 and is known as the world's largest in terms of the number and density of pterosaur footprints. This site has been managed by installing protection buildings to conserve in 2018. About 17% of the footprints of pterosaur, theropod, and ornithopod in this site under management in the 2nd protection building are of great academic value, but observation of footprints has difficulties due to continuous physical and chemical damage. In particular, the accumulation of milk-white contaminants is formed by the gypsum and air pollutant complex. Gypsum remains evaporated with a plate or columnar shape in the process of water circulation around the 2nd protection building, and the dust is from through the inflow of the gallery windows. The aqueous solution of gypsum, consisting of calcium from the lower bed and sulfur from grass growth, is catchmented into the groundwater from the area behind the protection building. Pollen and a few minerals other constituents of contaminants, go through the gallery window, which makes it difficult to expel dust. To conserve the fossil-bearing beds from two contaminants of different origins, controlling the water and atmospheric circulation of the 2nd protection building and removing the contaminants continuously is necessary. When cleaning contaminants, the steam cleaning method is sufficiently effective for powder-shaped milk-white contaminants. The fossil-bearing bed consists of dark gray shale with high laser absorption power; the laser cleaning method accompanies physical loss to fossils and sedimentary structures; therefore, avoiding it as much as possible is desirable.

• Journal of the Korean Wood Science and Technology
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• v.46 no.5
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• pp.449-470
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• 2018

A review of research trends on wood surface protection for exterior use obtained the following conclusions: It has been reported that inorganic compounds such as chrome and copper used as wood preservatives can protect wood from weathering. It has been shown that precoating with hydrophobic substances such as wax and oil, UV absorbers, and HALS (Hindered Amine Light Stabilizers) enhances weathering resistance on the surface of ACQ-treated wood. Opaque coatings of paint/stains and semitransparent stains on the surface of preservative treated wood can increase the synergistic effects on prevention of weathering deterioration. Also the need for repainting periodically for the protection of the preservative treated wood surface has also been suggested. ZnO or $TiO_2$ of fine particles, metal ions such as Co, Cr, Fe, Mn, Ni and Ti, and UV absorbers such as tris-resorcinol triazine derivatives, triazine and benzotriazole were introduced as additives for preventing UV in the transparent coating on wood. Several reports showed that chemical modification such as methylation, acetylation, or alkylations have made some increases the effects of preventing weathering with the increasing weight gain of chemical formulas. In heat-treated wood, there were various contradictory reports on the resistance of weathering, and there were some other reports emphasizing the necessity of painting with UV resistance, which leads to the necessity of more advanced studies.

• Journal of the Korean GEO-environmental Society
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• v.13 no.1
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• pp.37-43
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• 2012

Generally levee or revetment becomes weak by erosion (scour) due to saturation of ground with infiltration, flowing water. So when levee or revetment is constructed, slope reinforcement must be installed to prevent failure. In this study experimental test was performed for verifying shear resistance, horizontal permeability and rooting ability of Geocomb designed to address the shortcomings of 3-dimension Geocell. Geocomb is one of geosynthetics and the advanced system of geogrid. According to the results of shear test, internal friction angle of reinforced ground with Geocomb was increasing compared with existing material and horizontal permeability of ground with Geocomb was bigger than geocell, porous geocell reinforcing ground. Lastly rooting ability of geocomb is most excellent. These results determined for the inner surface of the cell is net structure.

• Journal of Korean Association for Spatial Structures
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• v.6 no.4 s.22
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• pp.73-80
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• 2006

It is an object of the present paper to investigate a electrochemical properties of Mg-based sacrificial anodes and the effect of calcium added from calcium chloride into magnesium on the melt protection during the melting. Electrochemical data will be correlated with processing control variables, and the microstructural change by the addition of CaCl2. Small addition of calcium into magnesium from CaCl2 imparts beneficial effect in electrochemical properties of Mg alloys, primarily, through microstructural modifications. In addition, the protection effect of the melts surface of Ca with low melting point modification is obtained by adding Ca not more than 0.6%.

• Journal of the Korean Geotechnical Society
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• v.29 no.1
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• pp.49-59
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• 2013

Heavy rainfall intensity may cause shallow slope failures and debris flow by rill erosion and scour on land surface. The paper represents the difference between native soil (weathered soil) and reinforced soil, which is mixed by hardening agent with flyash as main material, for investigating experimental findings of rill erosion and erosion. Results obtained from artificial rainfall simulator show that erosion rate of reinforced soil mixed with hardening agent is reduced by 20% because an amount of eroded soil on slope surface is inversely proportional to the increase of soil strength. For example, rainfall of 45mm (at the elapsed time of 25mins in rainfall intensity of 110mm/hr) triggers rill erosion on native soil surface, but the rill erosion on reinforced soil surface does not even occur at 330mm rainfall (at the elapsed time of 3hrs in rainfall intensity of 110mm/hr). As a result of slope stability analysis, it was found that the construction method for reinforced soil surface would be more economical, easy and fast construction technology than conventional reinforcement method.

• Korean Journal of Heritage: History & Science
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• v.46 no.4
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• pp.90-107
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• 2013

The Stone Monument of Taejong King in Heonreung Royal Tomb, Seoul was originally erected in 1424 to pay a tribute to Bang Won Lee's achievement who was named Taejong, the Third King of Joseon Dynasty. The monument has been damaged by Japanese Invasion of Korea in 1592 so that another monument was newly made and erected together with the original monument in 1695. The original monument was made of medium-grained biotite granite for the turtle base and medium-grained milky white crystalline limestone for the stele body and the top stone. The turtle base of the original monument is destroyed beyond the original shape and inscription due to irregular shaped breaking and a set of longitudinal crack. Analyzing the deterioration degree by using nondestructive methods, the 88 percentage of the front area and 38 percentage of the back area of the monument are damaged, and the lower part of the stele body is dominantly deteriorated especially due to the combination of discoloration and physical deterioration. The new monument in 1695 is also made of granite and limestone. The weathering indices of the turtle base and stele body stones by the calculation from ultrasonic velocity are 0.10 and 0.74, respectively. This is because the original monument is presumed to be degraded by heat shock and physical attack during the Japanese war, and the long-term outdoor exposure accelerated the weathering of the monument afterward without protective shelter.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.675-695
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• 2023

The tracksite of dinosaurs and pterosaurs in Sanbuk-dong of Gunsan is the largest early Cretaceous dinosaur footprint fossil site in Korea, and all the footprints are important evidence indicating that large ornithopod and theropod dinosaurs inhabited the Korean peninsula during the early Cretaceous. The Sanbuk-dong site was covered with waterproof sheet in an outdoor environment until the installation of a protective enclosure in 2021. As a result, various factors such as shear force, load reduction, temperature and humidity fluctuations, acid rain, salinity and microorganisms have complexly interacted in the substrate of fossils, exacerbating the damage to footprints. For 159 footprints in 12 trackways among the footprints found in the site, the damage types were classified in detail and the level of each damage was assessed. The damages were classified into 6 types through the classification of deterioration degree of individual footprints. As a result of ultrasonic physical property evaluation on the surface of the fossil site, most of these footprints are in the completely weathered (CW) stage. Furthermore, various weathering patterns were observed in the study area, and surface contaminants were analyzed along the stratigraphy. Although the patterns of freshness and contaminants varied at different points within the fossil site, the chemical compositions were similar. Based on the results, an efficient conservation management system for dinosaur footprint fossils was established, and a conservation treatment type for each footprint was proposed.

• Journal of the Korean Vacuum Society
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• v.20 no.3
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• pp.233-241
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• 2011

Currently, solar module is using the two methods such as a glass-filled method or a super-straight method. The common point of these methods is to use glass structure on the front of solar module. However, the reflectance of the solar module is high depending on the height of the incident sunlight due to the flat surface of the module front glass. Purposed to solve these problems, AG (anti-glare) structures were formed on the glass surface. Next is fabrication methods of AG structure. First, uneven structure made by micro blaster equipment was dipped in Hydro-fluidic acid (HF) acid. HF acid process was carried out to remove particles and to make high transmittance. The reflectance and transmittance of the anti-glare glass was compared to those of the bare glass. The reflectance of anti-glare glass decreased approximately 1% compared with bare glass. The transmittance of anti-glare glass was similar to bare glass. According to the sample angle, the difference of the reflectance between bare glass and the anti-glare glass was about 19%. Isc and efficiency value of anti-glare glass on bare solar cell appeared about 3.01 mA and 0.228% difference compared with bare glass. Anti-glare glass on textured solar cell appeared about 9.46 mA and 0.741% difference compared with bare glass. As a result, the role of anti-glare in the substrate is to reduces the loss of sunlight reflected from the surface. In this study, therefore, AG structure on the solar cell was used to improve the efficiency of solar cell.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.177-186
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• 2005

The latest concrete structure has showed that the deterioration of durability has been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the concrete which has deteriorated durability have been taken. Among them, it has been often used that surface treatment which cuts off the deterioration factors of durability by protecting the surface of concrete. However, troubles such as fracture and rupture in the repair layer have been reported as time goes by due to the difference between the organic repair material like epoxy and concrete properties. Researchers have been developing the repair material which can cut off the deterioration factors of durability such as $CO_2$ gas, chloride ion and water by making the formation of concrete elaborate through the reaction with calcium ion when the surface improving agent is coated on the concrete. The main ingredient of that is inorganic substance which is the same as the concrete property. This study was evaluated the surface improving agent for permeability, watertightness, air-permeability, chemical resistance and elution resistance. As a result, it has been reported that the surface improving agent improves watertightness and air-permeability by penetration more than 10mm within concrete. Therefore, it is concluded that the surface improving agent developed in this research prevents deterioration of concrete durability when it is coated on the concrete structure.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.155-169
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• 2004

Space launch vehicles and reentry vehicles are exposed to extreme heating conditions due to high aerodynamic heating while flying at high Mach numbers in the atmosphere. To protect the vehicle itself or the payload from the aerodynamic heating, the thermal load imposed on the surface should be exactly predicted and proper thermal protection should be applied based on the prediction results. But this requires rigorous thermal analysis and testing to prevent loss of payload capacity caused by excessive heat shielding, and the amount of thermal protection material to be applied is determined through aerodynamic heating tests. Various design points to be considered to upgrade the prototype aerodynamic thermal simulation facility(ATSF) used for the KSR-series sounding rocket development to the one suitable for the KSLV(Korean Space Launch Vehicle)-series launch vehicle are considered in this research. The need and limitation for the facility are first considered, and the functions required for KSLV testing are determined. The specifications of the upgraded facility are briefly suggested and these results will be used for the future fabrication and installation of the facility.