• Economic and Environmental Geology
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• v.22 no.1
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• pp.35-63
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• 1989

Geochemical characteristics of the Guryongsan (Ogcheon) uraniferous black slate show that this is an analogue to the conventional Chattanooga and Alum shales in occurrences. Whereas, its highest enrichment ratio in metals including uranium, among others, is explained by the cyclic sedimentation of the black muds and quartz-rich silts, and the uniform depositional condition with some what higher pH condition compared to the conditions of the known occurrences. The cyclic sedimentation, caused by the periodic open and close of the silled basin, has brought about the flush-out) of the uranium depleted water and the recharge with the new metal-rich sea water, which consequently contributed to the high concentration of metals in mud. The metal-rich marine black muds, which mostly occur in the early to middle Palaeozoic times, is attributed by the geologic conditions which related to the atmospheric oxygen contents, and these are scarcely met in the late Precambrian and/or with the onset of Palaeozoic era in the geologic evolution of the earth.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.30-40
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• 1995

The relationship between dietary intake and vitamin/mineral supplement usage was examined in 706 adolescent girls who were high school students. 43.8% of subjects used vitamin/mineral supplements during one year. The higher the family income and parents education level, the higher percentage of vitamin/mineral supplement usage was. But there was no significant difference between grades and scores. And vitamin/mineral supplement usage was higher int he thin and obese groups than the average weight groups. Nutrition knowledge and food habit did not affect vitamin/mineral supplement usage. Calorie intakes of vitamin/mineral supplement users and nonusers were similar. However, independent of the supplements, the diets of supplement nonusers contained significantly more dietary protein, vitamin A, vitamin $B_2$, niacin, vitamin C, and calcium than the diets of the users. A considerable portion of both the users and nonusers had dietary intakes of less than 2/3 of the Recommended Dietary Allowances for vitamin $B_1$, vitamin $B_2$, niacin, calcium, and iron. Vitamin/mineral supplement nonusers generally consumed a more vitamin, mineral from diet. Reasons for taking supplements were to take energy, advice and illness.

• The Journal of Korean Society for Radiation Therapy
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• v.30 no.1_2
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• pp.177-183
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• 2018

Purpose : Volumetric Modulated Arc Therapy(VMAT) has the advantage of uniformly and precisely irradiating the tumor to the shape of the tumor while reducing the risk of radiation damage to normal tissues. such as brain cancer, head and neck cancer and prostate cancer, It is being used for treatment. The purpose of this study is to evaluate the usefulness of the Jaw-Tracking technique(JTT) in VMAT for brain and head and neck cancer. Materials and Methods : We selected eight patients with brain and head and neck cancer(4 Brain, 4 head and neck) who were treated with the VMAT treatment technique. Contouring information of the patient's tumor and normal organ was fused to the Rando phantom using the deformable registration of Velocity(Varian, USA). A treatment plan was developed using the Varian Eclipse(ver 15.5, Varian, USA) with the same patient actual beam parameters except for the use of jaw-tracking. As the evaluation index, the maximum dose and mean dose of target and OAR were compared and a portal dosimetry was performed for the treatment plan verification. Results : When using JTT, the relative dose of OAR decreased by 5.24 % and the maximum dose by 7.05 %, respectively, compared with the Static-Jaw technique(SJT). In the various OARs, the mean dose and maximum dose reduction ranges ranged from 0.01 to 3.16 Gy and from 0.12 to 6.27 Gy, respectively. In the case of the target, the maximum dose of GTV, CTV, PTV decreased by 0.17 %, 0.43 %, and 0.37 % in JTT, and the mean dose decreased by 0.24 %, 0.47 % and 0.47 %, respectively. Gamma analysis The JTT and SJT passing rates were $98{\pm}1.73%$ and $97{\pm}1.83%$ on the basis of 3 % / 3 mm, respectively. Comparing the doses of all OARs applied to the experiment, it was found that the use of JTT resulted in a significant decrease in dose due to additional jaw shielding besides MLC than SJT. Conclusion : In radiation therapy using VMAT treatment plan, we can apply JTT in the case of adjacent tumor and normal organs such as brain cancer and head and neck cancer, and in radiotherapy required large field and high energy caused increase leakage dose through MLC. It is considered that the target dose of PTV can be increased by lowering the dose of normal tissue surrounding the tumor.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.41 no.4
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• pp.341-350
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• 2015

Skin carrys out protective role against harmful outer environment assaults including ultraviolet radiation, heavy metals and oxides. Especially, ultraviolet-B (UVB) light causes inflammatory reactions in skin such as sun burn and erythma and stimulates melanin pigmentation. Furthermore, the influx of UVB into skin cells causes DNA damage in keratinocytes and dermal fibroblasts, inhibition of extracellular matrix (ECM) synthesis which leads to a decrease in elasticity of skin and wrinkle formation. It also damages dermal connective tissue and disrupts the skin barrier function. Prolonged exposure of human skin to UVB light is well known to trigger severe skin lesions such as cell death and carcinogenesis. Haloarcula vallismortis is a halophilic microorganism isolated from the Dead Sea, Its growth characteristics have not been studied in detail yet. It generally grows at salinity more than 10%, but the actual growth salinity usually ranges between 20 to 25%. Because H. vallismortis is found mainly in saltern or salt lakes, there could exist defense mechanisms against strong sunlight. One of them is generation of additional ATP using halorhodopsin which absorbs photons and produces energy by potential difference formed by opening the chloride ion channel. It often shows a color of pink or red because of their high content of carotenoid pigments and it is considered to act as a defense mechanism against intense UV irradiation. In this study, the anti-inflammatory effect of the halophilic microorganism, H. vallismortis, extract was investigated. It was found that H. vallismortis extract had protective effect on DNA damage induced by UV irradiation. These results suggest that the extract of halophilic bacterium, H. vallismortis could be used as a bio-sunscreen or natural sunscreen which ameliorate the harmful effects of UV light with its anti-inflammatory and DNA protective properties.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.399-407
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• 2009

Laser induced breakdown spectroscopy(LIBS) is an simple analysis method for directly quantifying many kinds of soil micro-elements on site using a small size of laser without pre-treatment at any property of materials(solid, liquid and gas). The purpose of this study were to find an optimum condition of the LIBS measurement including wavelengths for quantifying soil elements, to relate spectral properties to the concentration of soil elements using LIBS as a simultaneous un-breakdown quantitative analysis technology, which can be applied for the safety assessment of agricultural products and precision agriculture, and to compare the results with a standardized chemical analysis method. Soil samples classified as fine-silty, mixed, thermic Typic Hapludalf(Memphis series) from grassland and uplands in Tennessee, USA were collected, crushed, and prepared for further analysis or LIBS measurement. The samples were measured using LIBS ranged from 200 to 600 nm(0.03 nm interval) with a Nd:YAG laser at 532 nm, with a beam energy of 25 mJ per pulse, a pulse width of 5 ns, and a repetition rate of 10 Hz. The optimum wavelength(${\lambda}nm$) of LIBS for estimating soil and plant elements were 308.2 nm for Al, 428.3 nm for Ca, 247.8 nm for T-C, 438.3 nm for Fe, 766.5 nm for K, 85.2 nm for Mg, 330.2 nm for Na, 213.6 nm for P, 180.7 nm for S, 288.2 nm for Si, and 351.9 nm for Ti, respectively. Coefficients of determination($r^2$) of calibration curve using standard reference soil samples for each element from LIBS measurement were ranged from 0.863 to 0.977. In comparison with ICP-AES(Inductively coupled plasma atomic emission spectroscopy) measurement, measurement error in terms of relative standard error were calculated. Silicon dioxide(SiO2) concentration estimated from two methods showed good agreement with -3.5% of relative standard error. The relative standard errors for the other elements were high. It implies that the prediction accuracy is low which might be caused by matrix effect such as particle size and constituent of soils. It is necessary to enhance the measurement and prediction accuracy of LIBS by improving pretreatment process, standard reference soil samples, and measurement method for a reliable quantification method.

• Korean Journal of Remote Sensing
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• v.37 no.5_3
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• pp.1373-1387
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• 2021

Forest fire poses a significant threat to the environment and society, affecting carbon cycle and surface energy balance, and resulting in socioeconomic losses. Widely used multi-spectral satellite image-based approaches for burned area detection have a problem in that they do not work under cloudy conditions. Therefore, in this study, Sentinel-1 Synthetic Aperture Radar (SAR) data from Europe Space Agency, which can be collected in all weather conditions, were used to identify forest fire damaged area based on a series of processes including Principal Component Analysis (PCA) and K-means clustering. Four forest fire cases, which occurred in Gangneung·Donghae and Goseong·Sokcho in Gangwon-do of South Korea and two areas in North Korea on April 4, 2019, were examined. The estimated burned areas were evaluated using fire reference data provided by the National Institute of Forest Science (NIFOS) for two forest fire cases in South Korea, and differenced normalized burn ratio (dNBR) for all four cases. The average accuracy using the NIFOS reference data was 86% for the Gangneung·Donghae and Goseong·Sokcho fires. Evaluation using dNBR showed an average accuracy of 84% for all four forest fire cases. It was also confirmed that the stronger the burned intensity, the higher detection the accuracy, and vice versa. Given the advantage of SAR remote sensing, the proposed statistical processing and K-means clustering-based approach can be used to quickly identify forest fire damaged area across the Korean Peninsula, where a cloud cover rate is high and small-scale forest fires frequently occur.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.347-355
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• 2021

During the earthquake, for multi-story structure, if the first floor is soft, the deformation will concentrate on that floor causing a serious damage to the column members which might leads to the collapse of the whole structure like Piloti structure during the Pohang earthquake in Korea. According to the 2016 National Disaster Management Research Institute's "Investigation of Seismic Reinforcement and Cost Analysis of Domestic Non-seismic Buildings", the rate of seismic resistance of private reinforced concrete buildings was 38.3 %. Among them, it was reported that the seismic-resistance ratio of the two to five-story structures was less than 50 %. Accordingly, the government is trying to improve the seismic rate through support projects, but the conventional seismic reinforcement methods are still expensive, and emergency construction is difficult. Therefore, in this study, the field applicability was evaluated by improving the reinforcement method using Velcro, which was developed through the research project of the Ministry of Land, Transport and Maritime Affairs in 2014. In order to improve the performance of the Velcro reinforcement method, introducing the initial tension of Velcro using high foaming rigid urethane filling between the Velcro and concrete of the columns was applied. Additionally, an experiment was conducted to evaluate the ductility of Velcro specimen from the concrete confinement effect. As a result, the ductility of the Velcro specimen was improved compare to Normal specimen. However, the energy dissipation capacity of VELCRO2 is better than VELCRO1, yet the maximum ductility of those two specimens did not show a significant difference. Therefore, the improvement of the internal filler material is still needed to have a better maximum ductility.

• Clean Technology
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• v.27 no.4
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• pp.359-366
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• 2021

Halloysite nanotubes (HNTs), the multiwalled clay mineral with the composition of Al₂Si₂O₅(OH)₄·nH₂O, have been highlighted as a low-cost adsorbent for the removal of dyes from wastewater. Although a powder of halloysite presents a high specific surface area, forming media are significantly considered due to sludge-clogging induced by the water-bound agglomeration. However, higher firing temperature to achieve the structural durability of the media and lower utilization rate due to longer penetration depth into the media act as hurdles to increase the dye-adsorption capacity. In this work, the retention of the adsorption capacity of halloysite was evaluated with methylene blue solution after the heat treatment at 750 ℃. In order to improve the utilization rate, tubular media were fabricated by extrusion. The images taken by transmission electron microscopy show that HNTs present excellent structural stability under heat treatment. The HNTs also provide superb capacity retention for MB adsorption (93%, 18.5 mg g^-1), while the diatomite and Magnesol^® XL show 22% (7.65 mg g^-1) and 6% (11.7 mg g^-1), respectively. Additionally, compositing with lignin enhances adsorption capacity, and the heat treatment under the hydrogen atmosphere accelerates the adsorption in the early stage. Compared to the rod-type, the tubular halloysite media rapidly increases methylene blue adsorption capacity.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1108-1119
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• 2018

As the interest on the air pollution is gradually rising at home and abroad, automotive and fuel researchers have been studied on the exhaust and greenhouse gas emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative after-treatment systems, using clean (eco-friendly alternative) fuels and fuel quality improvement. This research has brought forward two main issues : exhaust emissions (regulated and non-regulated emissions, PM particle matter) and greenhouse gases of vehicle. Exhaust emissions and greenhouse gases of automotive had many problem such as the cause of ambient pollution, health effects. In order to reduce these emissions, many countries are regulating new exhaust gas test modes. Worldwide harmonized light-duty vehicle test procedure (WLTP) for emission certification has been developed in WP.29 forum in UNECE since 2007. This test procedure was applied to domestic light duty diesel vehicles at the same time as Europe. The air pollutant emissions from light-duty vehicles are regulated by the weight per distance, which the driving cycles can affect the results. Exhaust emissions of vehicle varies substantially based on climate conditions, and driving habits. Extreme outside temperatures tend to increasing the emissions, because more fuel must be used to heat or cool the cabin. Also, high driving speeds increases the emissions because of the energy required to overcome increased drag. Compared with gradual vehicle acceleration, rapid vehicle acceleration increases the emissions. Additional devices (air-conditioner and heater) and road inclines also increases the emissions. In this study, three light-duty vehicles were tested with WLTP, NEDC, and FTP-75, which are used to regulate the emissions of light-duty vehicles, and how much emissions can be affected by different driving cycles. The emissions gas have not shown statistically meaningful difference. The maximum emission gas have been found in low speed phase of WLTP which is mainly caused by cooled engine conditions. The amount of emission gas in cooled engine condition is much different as test vehicles. It means different technical solution requires in this aspect to cope with WLTP driving cycle.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.7
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• pp.848-857
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• 2018

Recently, around the world, active development of new renewable energy sources including solar power, waves, and fuel cells, etc. has taken place. Particularly, floating offshore wind farms have been developed for saving costs through large scale production, using high-quality wind power and minimizing noise damage in the ocean area. The development of floating wind farms requires an evaluation of the Maritime Safety Audit Scheme under the Maritime Safety Act in Korea. Floating wind farms shall be assessed by applying the line and area concept for systematic development, management and utilization of specified sea water. The development of appropriate evaluation methods and standards is also required. In this study, proper standards for marine traffic surveys and assessments were established and a systemic treatment was studied for assessing marine spatial area. First, a marine traffic data collector using AIS or radar was designed to conduct marine traffic surveys. In addition, assessment methods were proposed such as historical tracks, traffic density and marine traffic pattern analysis applying the line and area concept. Marine traffic density can be evaluated by spatial and temporal means, with an adjusted grid-cell scale. Marine traffic pattern analysis was proposed for assessing ship movement patterns for transit or work in sea areas. Finally, conceptual design of a Marine Traffic and Safety Assessment Solution (MaTSAS) was competed that can be analyzed automatically to collect and assess the marine traffic data. It could be possible to minimize inaccurate estimation due to human errors such as data omission or misprints through automated and systematic collection, analysis and retrieval of marine traffic data. This study could provides reliable assessment results, reflecting the line and area concept, according to sea area usage.