• Journal of Conservation Science
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• v.27 no.2
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• pp.223-229
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• 2011

Buddha painting cultural properties couldn't avoid the change of colors and the exfoliation phenomenon by the characteristic of material and environmental factors. Especially, because in the beginning of the fine crack and the decoloration phenomenon on the surface of pigment would be significantly decrease stability of the whole object, it is necessary to take particular measure. Therefore, this is a study on conservation of Avalokitesvara in Potalaka in Hyeondeungsa in Gapyeong. It treated damaged parts of the object, carried out backing papers and matching colors. And then, it examined scientific analysis of pigments. Also, it performed nondestructive testing like XRF, FT-IR, and image microscope to investigate the quality of the material of hanji using the object and the component and characteristic of pigments. As a result, FT-IR spectrum matching Korean traditional paper(hanji) was detected in hanji of Avalokitesvara in Potalaka in Hyeondeungsa. The black pigment making a thin layer over the white pigment would estimate carbon compounds of unconfirmed ink stick or soot as XRF and FT-IR. Also, the white pigment was lead white($PbCO_3{\cdot}Pb(OH)_2$) involving Pb(Lead) and a carbonate. It was observed that the crystal of blue pigment had the different sizes of the particles from the microscope. In the case of this blue pigment, it showed cobalt blue and lead white was mixed when it used because both Cu and Pb were highly detected in XRF data.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.646-651
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• 2009

In this study, it was intended to prepare a stem volume table (with or without bark) and a stand yield table for Juglans mandshurica, plantations in Chungju, located in Chungcheongbuk-do, Korea. For the calculation of stem volume, we applied Kozak's growth model, which showed the best fitness index (97%). With this model, it was able to prepare the first yield table for Juglans mandshurica in Korea. Site index model, an indicator of forest productivity, was derived by using the Chapman-Richard model, in which the basic stand age was set to 30 years. The resulted site index ranged between 16 and 22. Based on the yield table of Juglans mandshurica resulted from this study, the volume for a 70-year-old stand with a midium site index class was estimated to be $238m^3/ha$, which is $100m^3/ha$ higher than the volume estimated from the yield table of Quercus acutissima. The yield table of oak trees has been used in the estimation of most broadleaf stands in Korea. However, the result of this study indicated that it is necessary to generate a stand yield table for each broadleaf species. The annual $CO_2$ removals of 30-year-old Juglans mandshurica plantations in the ChungJu region was estimated to be $5.84tCO_2/ha$. The stem volume and stand yield table of Juglans mandshurica plantation resulted from this study would provide a good information in decision making for forest management in ChungJu region.

• Korean Journal of Microbiology
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• v.50 no.3
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• pp.191-200
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• 2014

Gas hydrates play a significant role in the global carbon cycle and climate change because methane, a greenhouse gas, can be released from the dissociation of gas hydrate. Anaerobic oxidation of methane (AOM) is an important process that consumes more than 90% of the methane released into the hydrosphere and atmosphere. In this study, the microbial community associated with the methane gas hydrate sediment in the Ulleung basin, East Sea of Korea (UBGH) was analyzed by phylogenetic analysis of the mcrA and 16S rRNA gene libraries. A vertical stratification of the dominating anaerobic methane oxidizer (ANME)-1 group was observed at the surface and the sulfate methane transition zone (SMTZ). The ANME-2c group was found to be dominant in the high methane layer. The archaea of marine benthic group B, which is commonly observed in the AOM region, accounted for more than 50% of the identifications in all sediments. Nitrate reducing bacteria were predominant at SMTZ (Halomonas: 56.5%) and high methane layer (Achromobacter: 52.6%), while sulfate reducing bacteria were not found in UBGH sediments. These results suggest that the AOM process may be carried out by a syntrophic consortium of ANME and nitrate reducing bacteria in the gas hydrates of the Ulleung Basin of the East Sea.

• Korean Journal of Ecology and Environment
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• v.41 no.spc
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• pp.27-34
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• 2008

The vertical distribution and origin of particulate organic matter (POM) were investigated in Shingu reservoir on 4th July (pre-monsoon) and 7th August (post-monsoon) 2006. High turbid water (120 NTU) were found at 4.5 m water depth in postmonsoon period. The average C/N ratio of POM was about 5.70 and 6.96 in surface water and bottom water, respectively in pre-monsoon period, exhibiting the close values to its ratio in phytoplankton cell. However, the average C/N ratio was 7.10 in surface water and 12.81 in bottom water in post-monsoon period. In addition, the ${\delta}^{13}C$ values of POM in pre-monsoon period ranged from -25.1%o to -26.1%o in whole water column, but the ${\delta}^{13}C$ values of POM in post-monsoon period showed relatively wide range between -23.2%o and -27.5%o. The apparently lighter values (average -27.5%o) in near bottom water (4.5 m water depth) demonstrate that POM in high turbid water in post-monsoon period may be derived from the outside terrestrial plants through heavy rainfall during the summer monsoon period. The present study suggests that carbon and nitrogen stable isotope ratios as well as C/N ratios should be useful indexes to clarify the origin of POM.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.117-123
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• 2021

In this study, the composite was prepared by mixing SiOx, soft carbon, and carbon black and the electrochemical properties of lithium ion battery were investigated. The content of SiOx added to improve the capacity of the soft carbon anode material was varied to 0, 6, 8, 10, 20 wt%, and carbon black was added as a structural stabilizer for reducing the volume expansion of SiOx. The physical properties of prepared CB/SiOx/C composite were investigated through XRD, SEM, EDS and powder resistance analysis. In addition, the electrochemical properties of prepared composite were observed through the charge/discharge capacity, rate and impedance analysis of the lithium ion battery. The prepared CB/SiOx/C composite had an inner cavity capable of mitigating the volume expansion of SiOx by adding carbon black. The formed internal cavity showed a low initial efficiency when the SiOx content was less than 8 wt%, and low cycle stability when the content of SiOx was less than 20 wt%. The CB/SiOx/C composite containing 10 wt% of SiOx showed an initial discharge capacity of 537 mAh/g, a capacity retention rate of 88%, and a rate of 79 at 2C/0.1C. SiOx was added to improve the capacity of the soft carbon anode material, and carbon black was added as a structural stabilizer to buffer the volume change of SiOx. In order to use the CB/SiOx/C composite as a high-efficiency anode material, the mechanism of the optimal SiOx and the use of carbon black as a structural stabilizer was discussed.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.60-76
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• 2022

This study presents a software full setup and the following test execution times in a Linux cluster for the United Kingdom Earth System Model (UKESM) and then compares the model results from control and experimental simulations of the UKESM relative to various observations. Despite its low resolution, the latest version of the UKESM can simulate tropospheric chemistry-aerosol processes and the stratospheric ozone chemistry using the United Kingdom Chemistry and Aerosol (UKCA) module. The UKESM with UKCA (UKESM-UKCA) can treat atmospheric chemistryaerosol-cloud-radiation interactions throughout the whole atmosphere. In addition to the control UKESM run with the default CMIP5 SO₂ emission dataset, an experimental run was conducted to evaluate the aerosol effects on meteorology by changing atmospheric SO₂ loading with the newest REAS data over East Asia. The simulation period of the two model runs was 28 years, from January 1, 1982 to December 31, 2009. Spatial distributions of monthly mean aerosol optical depth, 2-m temperature, and precipitation intensity from model simulations and observations over East Asia were compared. The spatial patterns of surface temperature and precipitation from the two model simulations were generally in reasonable agreement with the observations. The simulated ozone concentration and total column ozone also agreed reasonably with the ERA5 reanalyzed one. Comparisons of spatial patterns and linear trends led to the conclusion that the model simulation with the newest SO₂ emission dataset over East Asia showed better temporal changes in temperature and precipitation over the western Pacific and inland China. Our results are in line with previous finding that SO₂ emissions over East Asia are an important factor for the atmospheric environment and climate change. This study confirms that the UKESM can be installed and operated in a Linux cluster-computing environment. Thus, researchers in various fields would have better access to the UKESM, which can handle the carbon cycle and atmospheric environment on Earth with interactions between the atmosphere, ocean, sea ice, and land.

• The Journal of Engineering Geology
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• v.33 no.4
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• pp.543-553
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• 2023

The current status of domestic a agalmatolite mines in South Korea was investigated with a view to establishing a stable supply of agalmatolite and managing its demand. Most mined agalmatolite deposits were formed through hydrothermal alteration of Mesozoic volcanic rocks. The physical characteristics of pyrophyllite, the main constituent mineral of agalmatolite, are as follows: specific gravity 2.65~2.90, hardness 1~2, density 1.60~1.80 g/cm³, refractoriness ≥29, and color white, gray, grayish white, grayish green, yellow, or yellowish green. Among the chemical components of domestic agalmatolite, SiO₂ and Al₂O₃ contents are respectively 58.2~67.2 and 23.1~28.8 wt.% for pyrophyllite, 49.2~72.6 and 16.5~31.0 wt.% for pyrophyllite + dickite, 45.1 and 23.3 wt.% for pyrophyllite + illite, 43.1~82.3 and 11.4~35.8 wt.% for illite, and 37.6~69.0 and 19.6~35.3 wt.% for dickite. Domestic agalmatolite mines are concentrated mainly in the southwest and southeast of the Korean Peninsula, with some occurring in the northeast. Twenty-one mines currently produce agalmatolite in South Korea, with reserves in the order of Jeonnam (45.6%) > Chungbuk (30.8%) > Gyeongnam (13.0%) > Gangwon (4.8%), and Gyeongbuk (4.8%). The top 10 agalmatolite-producing mines are in the order of the Central Resources Mine (37.9%) > Wando Mine (25.6%) > Naju Ceramic Mine (13.4%) > Cheongseok-Sajiwon Mine (5.4%) > Gyeongju Mine (5.0%) > Baekam Mine (5.0%) > Minkyung-Nohwado Mine (3.3%) > Bugok Mine (2.3%) > Jinhae Pylphin Mine (2.2%) > Bohae Mine. Agalmatolite has low thermal conductivity, thermal expansion, thermal deformation, and expansion coefficients, low bulk density, high heat and corrosion resistance, and high sterilization and insecticidal efficiency. Accordingly, it is used in fields such as refractory, ceramic, cement additive, sterilization, and insecticide manufacturing and in filling materials. Its scope of use is expanding to high-tech industries, such as water treatment ceramic membranes, diesel exhaust gas-reduction ceramic filters, glass fibers, and LCD panels.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.149-157
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• 2003

This study focused on relationships between Pb and Cd concentrations and the difference of success reproductive progress in urban (Seoul) and industrial complex (Ansan) areas. Results of the Pb analysis for the feral pigeons from Seoul (egg contents:1.64 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 29.5 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan industrial complex (egg contents: 1.13 $\mu\textrm{g}$ wet $g^{-1}$, adults in bones: 10.5 $\mu\textrm{g}$ wet g-1) showed that the Pb level of eggs and adults is significantly different between the two colonies (p<0.05). Cd concentrations in liver and kidneys of adult pigeons were also significantly different between Seoul(liver: 0.24 ${\mu}g$ wet $g^{-1}$, kidney: 1.05 $\mu\textrm{g}$ wet $g^{-1}$ and the Ansan (liver: 0.14 $\mu\textrm{g}$ wet $g^{-1}$, kidney: 0.43 $\mu\textrm{g}$ wet $g^{-1}$ colonies (P<0.05). Clutch size of Feral Pigeons living in Seoul was similar between the two colonies, 1.9$\pm$0.3 in Seoul and 2.0$\pm$0.0 in Ansan. The length, breadth, and thickness of eggs were not significantly different between the two colonies (p>0.05). Incubation period in Seoul (17.8 days) did not differ from the Ansan (17.4 days). No difference in growth rate (body weight, wing length, and tarsus length) was found between the two test groups (p>0.05). In Seoul, 65.2% were hatching, and 42.1% fledging. The Proportion of hatching and fledging in the Ansan was 60.7% and 45.0%, respectively. The significant differences between the two colonies for reproductive sucess were not found (p>0.05). With regard to the reproductive effects to the heavy metals, the Pb and Cd concentrations feund in the two colonies were not as high as those considered in results of toxic effects in other species.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.133-140
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• 2003

In this study, muscle activity was measured using surface EMG (sEMG) during a voluntary maneuver (ankle dorsiflexion) in the supine position was compared pre and post gait training. Nine patients with incomplete spinal cord injury participated in a supported treadmill ambulation training (STAT), twenty minutes a day, five days a week for three months. Two tests, a gait speed test and a voluntary maneuver test, were made the same day, or at least the same week, pre and post gait training. Ten healthy subjects' data recorded using the same voluntary maneuvers were used for the reference. sEMG measured from ten lower limb muscles was used to observe the two features of amplitude and motor control distribution pattern, named response vector. The result showed that the average gait speed of patients increased significantly (p〈0.1) from 0.47$\pm$0.35 m/s to 0.68$\pm$0.52 m/s. In sEMG analysis, six out of nine patients showed a tendency to increase the right tibialis anterior activity during right ankle dorsiflexion from 109.7$\pm$148.5 $mutextrm{V}$ to 145.9$\pm$180.7 $mutextrm{V}$ but it was not significant (p〈0.055). In addition, only two patients showed increase of correlation coefficient and total muscle activity in the left fide during left dorsiflexion. Patients' muscle activity changes after gait training varied individually and generally depended on their muscle control abilities of the pre-STAT status. Response vector being introduced for quantitative analysis showed good Possibility to anticipate. evaluate, and/or guide patients with SCI, before and after gait training.

• Journal of Soil and Groundwater Environment
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• v.6 no.4
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• pp.51-59
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• 2001

Column and box tests were performed to investigate the removal efficiency of NAPL using the surfactant enhanced flushing In heterogeneous medium. Homogeneous Ottawa sand and heterogeneous soil were used to verify the increase of remediation efficiency for the surfactant enhanced flushing in column test. Box tests with two different heterogeneous sub-structure were performed to quantify the capability of the surfactant enhanced flushing as a remediation method to remove NAPL from the heterogeneous medium. Two different grain size sand layers were repeated in the box to simulate the heterogeneous layer formation and the modified fault structure was built to simulate the fault system in the box. O-xylene as a LNAPL and PCE as a DNAPL were used and oleamide as a non-ionic surfactant. The maximum NAPL effluent concentration with 1% oleamide flushing in the homogeneous column test increased about 460 times compared to that with only water flushing and about 250 times increased in the real soil column test. In heterogeneous medium, the maximum effluent concentration increased about 150 times in 1% oleamide flushing and most of NAPL were removed from the box within 8 pore volume flushing, suggesting that the removal efficiency increased very much compared to in only water flushing. Results investigated the capability of the surfactant enhanced remediation method to remove NAPL even in heterogeneous medium.