• Elastomers and Composites
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• v.42 no.2
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• pp.93-101
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• 2007

In this study, for enhancing the durability of permeable pavement material polyurethane(PU) adhesives were developed, and the physical properties upon polymerization and additives were studied. PU polymerization followed the bulk polymerization of free solvent type considering ecological aspect. Additives used in this study were carbon black, calcium carbonate and ultra violet stabilizer. The property changes upon different environment were evaluated with the compressive strength which is the principal measurement of the property of pavement materials. Among polymerized PU, one formulated with esterpolyol and crosslinkable chain extender gave the highest compressive strength of $74.9kgf/cm^2$, better than commercial $60kgf/cm^2$. The strength was the highest when the material specimen contained carbon black and calcium carbonate 20 wt%, respectively. However, UV stabilizer did not show good weathering properties.

• Journal of the Korean Geographical Society
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• v.46 no.1
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• pp.1-19
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• 2011

The physical and chemical characteristics of loess-paleosol sequence in Jeongjang-ri, Geochang basin are examined using the magnetic susceptibility measurement, grain size analysis, OSL age dating, major, rare earth and trace elements analysis. The grain size characteristics of the loess-palesol sequence are obviously different from those of river sediment forming river terrace deposits and the Chinese Loess Plateau. The loess-paleosol sequence consisting of L1, L1LL1, L1S1, L1L2, S1 and L2 from top to bottom is estimated to MIS 2~MIS 6 and the river terrace to MIS 7. The compositions of major, rare earth and trace elements indicate that the sequence show more weathered characteristics than the Chinese Loess Plateau and originated from the Chinese Loess Plateau. These features are in harmony with the previous studies in Korea.

• Journal of the Korean Geographical Society
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• v.45 no.3
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• pp.360-374
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• 2010

The distributions, factors, and vegetation covers of debris slopes and changes of debris at the eastern Ongjeom-ri, Cheongsong-gun are analyzed. The important factors influencing on the developments of the slopes are felsites having advantages to the developments of cliffs and supply of enough debris, and the relatively long days below zero temperatures promoting the physical weathering processes. The distributional areas of the slopes at southern and western slopes are more extensive than those of northern and eastern slopes due to the active water evaporation by high insolation. The Ga area at eastern Ongjeom-ri has experienced the steady decreases of area of the slopes due to the vegetation covers and shows the increasing rates of vegetation covers of $431.0m^2/yr$ as averaged values. However, it is estimated at the Na area using terrestrial LIDAR that 1 or 2 debris were moved or displaed per year in slope.

• 한국해양학회지
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• v.30 no.4
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• pp.271-278
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• 1995

A study of heavy mineral sands in terms of heavy mineral group and concentration has been carried out by analyzing 88 grab samples from the continental shelf off the southeast coast of Korea. Heavy mineral groups seem to be outlined and classified into four regions in the study area: 1) the western region; high concentrations of stable minerals, such as opaque mineral, magnetite, garnet and ZTR, 2) Korean Trough region; moderate concentrations of stable minerals, 3) the eastern region; abundant altered mineral and amphibole with minor of pyroxene concentration, and 4) the northeastern shelf-break region; low concentration of stable minerals with abundant altered minerals. The sedimentologic natures of four major heavy mineral regions (groupings) seem to be influenced by physical, dynamic and hydraulic milieu and also aerial and/or subaqueous weathering processes. It seems to be, further, plausible that shallow marine waves and currents associated with neritic dynamic condition of transgressive sea might be very effective on the concentration and groupings (sorting) of heavy min-erals in the surficial sediments of the continental shelf. The pyroxene-abundant heavy mineral suite (group), in fact, seems to suggest a sediment source from Japanese Islands.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.3
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• pp.111-123
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• 2009

The purpose of this study is to investigate the time-elapse change of oil-polluted Taean coastal area with by Herbei Spirit oil spill incident. From Mandae of Iwonmeyon to Padori beach of Sowonmeyon, field monitering was conducted at eleven surveying points surveying. The specific conclusions from this study are as follows. The residual oil was not founded at ten surveying points, but the crude oil remained under the ground at the Groompo beach one year passed since the oil spill. Because the efforts of volunteers over millionaires and inhabitants for cleaning and reciprocating actions of waves, the oil-polluted coastal area by Herbei Spirit oil spill incident. It is guessed that a part of stranded oil spilled from the incident was degraded by physical, chemical, and biological weathering and the residue was dispersed in tidal and subtidal zone with oil-minerals aggregates(OMA).

• Economic and Environmental Geology
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• v.29 no.3
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• pp.305-313
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• 1996

In order to investigate the extent and degree of Cd, Cu, Pb and Zn contamination affected by mining activities of the Dalsung Cu~W mine, sampling of stream sediments and waters has been undertaken up to 1.5 km downstream from the mine at 50~150 meter intervals. Analysis of the samples was carried out using ICP-AES for Cd, Cu, Pb and Zn. Physical and chemical properties of sediments (pH, organic matter contents, cation exchange capacity) and waters (pH, Eh and temperature) were also measured. The properties of the sediment samples were characterized by low pH (3.0~5.5), low organic matter contents (2~5%) and a moderate degree of cation exchange capacity (7~15 meq/100 g) with a high proportion of sand fraction. The pH values of water samples ranged from 3.0 to 5.0 and the Eh levels were in the range of 350~530 mV. Concentrations of Cd, Cu, Pb and Zn in the sediments averaged 3.2 mg/kg, 1,390 mg/kg, 451 mg/kg and 262 mg/kg with the range of 0.6~11.4 mg/kg, 15~3,800 mg/kg, 14~1,330 mg/kg and 63~1,060 mg/kg, respectively. Significant levels of the heavy metals were also found in the water samples with the range of $10{\sim}170{\mu}gCd/l$, $300{\sim}41,600{\mu}gCu/l$, $10{\sim}80{\mu}gPb/l$ and $700{\sim}15,400{\mu}gZn/l$. These elevated concentrations in the sediments and waters may be caused by the weathering of mine waste materials and their high solubilities under acidic and/or oxidizing conditions. Although metal concentrations in the samples decrease with the distance from the mine, heavy metal contamination of sediments and waters were also found at the 1.5 km downstream due to the mobile conditions of the heavy metals, with particular reference to Cd and Zn in stream waters.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.181-191
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• 2015

The Bakseok of Geunjeongjeon Hall in Gyeongbokgung Palace is platy floor stone acting as drainage, protected glaring and sliding. The Bakseoks were composed of anisotropic medium-grained biotite granite with a weak myrmekitic texture. Interpretation of transportation process for the Bakseok and original granite provenance trace of and analyze of identity based on ancient writings and detail field survey. As a result, the very similar granite with the Bakseok in lithology, composition mineral, texture and geochemical characteristics was found around Mt. Nakgasan in the Seokmodo Island. There were interpreted stonework process of the Bakseok used exfoliation granite dome with physical weathering properties in Seokmodo Island, to get platy stone economically stonework at the state level as a minimized on burden of supply and men power.

• Tunnel and Underground Space
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• v.17 no.2 s.67
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• pp.83-89
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• 2007

Impact-echo test is a non-destructive testing method to determine dynamic properties of a material. This presentation introduces the experimental set-up and procedure of the test for rock specimens. In addition, the test results of domestic rocks collected in 5 different areas, a cement mortar and aluminium alloy are presented. The test results include resonance frequencies of P- and S-wave as well as damping ratios of the described 7 different materials. The differences between dynamic and static values of elastic moduli are about 10%, while the dynamic Poisson's ratios are greater than the static Poisson's ratios by at least 0.07. The damping ratio is dependent on the joint density and degree of weathering of a rock specimen.

• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.69-75
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• 2023

Recently, the application of paint protection films (PPFs) for automobiles having a self-recovery coating layer has been grown up. In this study, we report the evaluation results on the basic physical properties of a poly(vinyl chloride)- based PPF containing poly(urea-urethane) hybrid self-recovery coating layer. Depending on the main chemical composition and the thickness of poly(urea-urethane)-based coating layer for PPF, the self-recovery performance by an optical microscope and the stain resistance through color difference value are measured. To improve the surface properties and show its easy-cleaning effect against the polluted things, silicone-modified polyacrylate is introduced to the self-recovery coating composition. The contact angle of water on the coated surface is confirmed to show its hydrophobic surface. Finally, accelerated weathering test of paint protection film with poly(urea-urethane) hybrid coating layer is performed to check the possibility of discoloration and deformation due to long-term exposure on harsh condition.

• Journal of The Geomorphological Association of Korea
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• v.17 no.3
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• pp.1-16
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• 2010

Phytoliths, silica microfossil that produced within and between cells and tissues of plants are especially yielded in Gramineae with many different forms and can attribute to the reconstruction of climatic and environmental changes and agriculture activity of the Quaternary. The phytoliths in soil can remain for long periods of time, because of strong resistance to physical and chemical weathering. The spatial range of study is too small due to deposition of phytoliths directly to the soil. There are difficulties of phytoliths identification because of multiplicity and redundancy, so far uniform and exact classification scheme has not been adopted. Therefore we attempted phytolith classification system applied to Korea. The paleoenvironmental reconstruction research using phytholith are applicated in many parts of studies. Also high-resolution paleoclimatic reconstruction expected to be possible using phytolith indices of Iph and Ic as well as climatic indicator of phytolith morphology.