• Geophysics and Geophysical Exploration
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• v.27 no.1
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• pp.1-22
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• 2024

Carbon dioxide capture utilization and storage (CCUS) techniques have received significant global attention as they are part of efforts to achieve carbon neutrality by 2050. Large-scale carbon dioxide capture and storage (CCS) projects are being actively pursued in North America, the North Sea, the Middle East, and Oceania. Considering the current situation in South Korea, identifying large-scale CCS sites that can secure an annual domestic carbon storage capacity of 30 million tons by 2050 is crucial Therefore, this study analyzed the formation process and geological characteristics of overseas large-scale CCS projects in terms of plate tectonics. We utilized the GPlates program to interpret the formation processes of large-scale CCS projects in North America, the North Sea, Middle East, and Oceania from the perspective of plate tectonics. Additionally, we investigated the geological structure of the CO₂ storage layer and interpreted seismic imaging results obtained from each CCS site. This study will help identify a domestic large-scale CCS site.

• Journal of the Microelectronics and Packaging Society
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• v.31 no.1
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• pp.29-34
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• 2024

The heating element utilizing the Joule heating generated when current flows through a conductor is widely researched and developed for various industrial applications such as moisture removal in automotive windshield, high-speed train windows, and solar panels. Recently, research utilizing heating elements with various nanostructures has been actively conducted to develop flexible heating elements capable of maintaining stable heating even under mechanical deformation conditions. In this study, flexible polyurethane possessing excellent flexibility was selected as the substrate, and silver (Ag) thin films with low electrical resistivity (1.6 μΩ-cm) were fabricated as the heating layer using magnetron sputtering. The 2D heating structure of the Ag thin films demonstrated excellent heating reproducibility, reaching 95% of the target temperature within 20 seconds. Furthermore, excellent heating characteristics were maintained even under mechanically deforming environments, exhibiting outstanding flexibility with less than a 3% increase in electrical resistance observed in repetitive bending tests (10,000 cycles, based on a curvature radius of 5 mm). This demonstrates that polyurethane/Ag planar heating structure bears promising potential as a flexible/wearable heating element for curved-shaped appliances and objects subjected to diverse stresses such as human body parts.

• Applied Chemistry for Engineering
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• v.35 no.4
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• pp.321-328
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• 2024

The performance of carbon fluoride-based lithium primary batteries (Li/CF_X) is limited due to poor rate capability resulting from the low conductivity of carbon fluoride, which is used as the active material. Therefore, in this study, we applied a carbon coating using pyrolysis fuel oil on carbon fluoride to overcome this limitation and considered its electrochemical performance. An amorphous carbon layer was formed on the surface of the carbon fluoride through carbon coating, and the surface physicochemical properties of the carbon fluoride were meticulously considered based on the heat treatment temperature. The advanced research chemical 1000 heat treated at 450 ℃ (ARC@C450) sample, which was commercial carbon fluoride heat-treated at 450 ℃, showed the largest increase in the concentration of sp² carbon bonds (62%) and the highest formation of semi-ionic C-F bonds. Also, the primary battery using the ARC@C450 sample as a cathode active material exhibited stable discharge capability at the highest rate of 5 C (392 mAh/g), and the R_ct value was reduced by 53% compared to the untreated sample. Therefore, we proposed pyrolysis fuel oil-based carbon coating as a method to overcome the low conductivity of carbon fluoride, and the carbon-coated carbon fluoride showed excellent rate performance, suggesting its potential application in high-power primary batteries.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.163-171
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• 2024

This study applies neural network analysis techniques to examine the factors influencing the purchasing decisions of fashion eyewear among women in their 30s and 40s, comparing these findings with traditional parametric analysis methods. In the fashion area, machine learning techniques are utilized for personalized fashion recommendation systems. However, research on such applications in Korea remains insufficient. By reanalyzing a study conducted in 2017 using traditional quantitative methods with these new techniques, this study aims to confirm the utility of neural network methods. Notably, the study finds that the classification accuracy of preferred sunglasses design is highest, at 86.2%, when the L-BFGS-B neural network is activated using the hyperbolic tangent function. The most critical factors influencing purchasing decisions were consumers' occupations and their pursuit of new styles. It is interpreted that Korean sunglasses consumers prefer "safe changes." These findings are consistent for selecting both the frames and lenses of sunglasses. Traditional quantitative analysis suggests that the type of sunglasses preferred varies according to the group to which a consumer belongs. In contrast, neural network analysis predicts the preferred sunglasses for each individual, thereby facilitating the development of personalized sunglasses recommendation systems.

• Journal of the Korea Organic Resources Recycling Association
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• v.32 no.3
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• pp.57-66
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• 2024

In this study, silicon sludge from a semiconductor packaging process is recycled to fabricate silica coated silicon-sludge and applied as a filler for an epoxy molding compound(EMC). Silicon-sludge powder(S-sludge) is treated with acid to remove metallic impurities and then coated using the sol-gel method to synthesize silica coated silicon-sludge powder(SS-sludge). The as-synthesized SS-sludge is subsequently mixed with epoxy resin, a curing agent, and carbon black to create an EMC(SS-sludge EMC). The heat dissipation properties of the EMC were examined using an IR camera. IR camera analysis confirmed that the SS-sludge EMC exhibited the highest surface temperature of 58.5℃ compared to SiO₂-based EMC. This enhancement in heat dissipation using SS-sludge EMC is attributed to the excellent thermal conductivity(150W/mK) of the silicon substrate and the presence of the silica layer on the SS-sludge surface which effectively enhances the thermal property of the EMC. Therefore, this study successfully demonstrates the recycling of silicon sludge from a semiconductor packaging process by synthesizing silica coated silicon-sludge and suggests a novel application of this material in semiconductor packaging.

• Korean Journal of Mineralogy and Petrology
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• v.37 no.2
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• pp.35-46
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• 2024

This study investigated the origin and mineralogical-geochemical characteristics of a small ferromanganese (Fe-Mn) nodule sample obtained from the abyssal seafloor of the Magellan Seamount cluster. To this end, X-ray diffraction and X-ray fluorescence analyses were conducted. The dark brown Fe-Mn oxides constituting the nodule had a homogeneous texture without distinguishable layers, forming around three distinct nuclei. The oxides had a low average Mn/Fe ratio of 0.73 (0.24-1.10) and were characterized by high Co content (0.41-0.85 wt.%, average = 0.58 wt.%) as well as low Ni (0.06-1.24 wt.%, average = 0.55 wt.%) and Cu (0.27-1.02 wt.%, average = 0.59 wt.%) concentrations. The maximum age of the nodule was estimated at 0.52 Ma, suggesting that it began forming during the transition from the glacial to the interglacial periods in the middle Pleistocene. The Fe-Mn oxide layer comprised vernadite, smectite, quartz, and feldspar, while the nuclei were composed of soft sediments. The presence of vernadite, a typical hydrogenetic Fe-Mn oxide mineral, along with the low Mn/Fe ratio, high Co content, and low Ni and Cu concentrations, indicates that Fe-Mn nodules on the abyssal seafloor of the Magellan Seamount cluster in the western Pacific Ocean formed through hydrogenetic processes.

• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.551-558
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• 2011

This present study was performed to analyze the efficiency and volatility of a porous film containing $Chamaecyparis$ $obtusa$ extract as a method to effectively package food compounds. Phytoncide was contacted the state of gas and showed effective antimicrobial properties. Limonene can be distilled without decomposition as a relatively stable terpene and was one of the extract components. $Chamaecyparis$ $obtusa$ essential oil. The optimal solvent composition was a ratio 5:20:0.3 of T-500:ethanol:hardener to effectively manufacture film containing phytoncide essential oil and the minimum antibacterial concentration was 2%. The films were made under different conditions(A-50LF1, A-25SF2, B-50SF1, C-50LF1, C-25SF2 and D-50SF1) containing phytoncide and the amounts of limonene inside the 1-L reaction chamber depending on storage were measured by gas chromatography-mass selective detention. The results showed that the 25SF2(width, 25 mm; length, 20 cm) revealed more amount of limonene compared with 50LF1(width 50 mm, length 20 cm). We confirmed that the gas emission amount showed a better layer on the film side than on the internal film. An effect of film thickness on phytoncide emissions was observed in that the amounts was less than the expectation for a thicker film at the beginning time, but the emitting amounts increased with increasing storage periods. In the storage testing of various films at $35^{\circ}C$ and 70% humidity for 14 days, 25SF2 showed longer preservation compared with that of 50LF in the case of bread. $C.$ $obtusa$ essential oil is a useful fresh ingredients, hence, analysis of limonene emission kinetics from various film was helpful to develop films with an optimal antimicrobial effect, and will allow application of such films in food packaging systems.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.2
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• pp.98-104
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• 1994

Effects of paddy-upland rotation system on nutrients distribution in soil profile and nutrient balance were studied in paddy fields from 1989 to 1993. The obtained results are summarized as follows. 1. $NO_3{^-}-N$, Av.$P_2O_5$, Ex.-K, and EC were high by small extent in surface layer of 0~20cm soil depth without the sign of salt movement to deeper layers. On the contrary Ex.-ca, Ex.-Mg, and pH became high with increase of soil depths. 2. $NO_3{^-}-N$, Av.$P_2O_5$, Ex.-K, and EC in surface soil were high in the order of Converted, Paddy-Upland Rotation, Potato-Chinese Cabbage>2 Year, Rotation, Potato-Chinese Cabbage>Converted, Paddy-Upland Rotation, Soybean>Continous Paddy, which responded well to fertilizer application rates. On the other hand Ex.-Ca, Ex.-Mg, and pH in whole layers were high in the order of Converted, Paddy-Upland Rotation, Soybean>Converted, Paddy-Upland Rptation, Potato-Chinese Cabbage>2 Year, Rotation, Potato-Chinese Cabbage>Continuous Paddy, which largely depended on plant absorption. 3. Nutrient balance in upland cropping system cultivating potato and Chinese cabbage showed that the input of chemical fertilizer of nitrogen and potassium was less than the plant uptake, while it was reverse for phosphorus with much gap between fertilizer input and plant uptake. Therefore, phosporous was expected to be accumulated by 27kg/10a every year. 4. Nutrient balance in upland cropping system cultivating soybean showed that nitrogen was not deficient to soybean crops even the chemical fertilizer input was less than plant uptake because of nitrogen fixation by rhizobia. However, there was about 1kg/10a deficit of potassium, which resulted dificiency symptom in the middle stage of soybean growth. For phosphorous there was excess of 4kg/10a, which was expected to be short for maintaining phosphorous fertility of upland soils.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.3
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• pp.311-316
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• 2007

In this study, we investigated the presence of nitrogen, phosphorus, ions, heavy metals and other contaminations in the water stream and soil of the forest watershed with different geology and vegetations for one year from October 2004 to September 2005. Most of the nitrogen oxide in the soil was in the form of $NO_3^-$, and it appeared that nitrogen contents decreased as the soil depth increased. Nitrogen contents was highest in the basalt area showing 13.3 mg/g in the surface soil and 7.40 mg/g in the subsoil. Phosphorous contents showed no significant variations depending on the soil depth and was higher in the intermediate soil layer(60 cm) than in surface soil (30 cm) in granite and metamorphic rock areas. Nitrogenous compound in the soil water was 8.03 mg/L in the granite area of coniferous forest and 14.79 mg/L in the andesite area of the deciduous forest. Nitrogenous compound in the stream water was 5.53 mg/L in October and 6.99 mg/L in January in the granite area of the coniferous forest and $3.61\sim5.11$ mg/L in the andesite area of the deciduous forest. Phosphates in runoff and stream water were similar in coniferous with in deciduous forests, showing a slight increase(0.090$\sim$0.179 mg/L) in the basalt area. In the coniferous forest, pH showed a significant positive correlation with EC, $Ca^{2+}$ and $Cl^-$ at p < 0.01, and showed a negative correlation with S-Fe and S-Al. Electroconductivity showed a significant correlation of 0.601 with $Ca^{2+}$ and of -0.586 with $NO_3^-$ at p<0.01, and showed a significant correlation of 0.301 with $SO_4^{2-}$ and of -0.295 with S-Fe at p < 0.05. In the deciduous forest, pH showed a positive correlation with $Ca^{2+}$ at p < 0.05, and showed a negative correlation with $K^+$, S-Fe and S-Al at p < 0.01. Electroconductivity showed a significant positive correlation with $Ca^{2+}$ and $Cl^-$ at p < 0.05 and with $NO_3^-$ at p < 0.01.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.3
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• pp.502-509
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• 2003

After 800 students of Chonbuk National University was examined, 86 people (male : 43, female : 43, mean age : 22.2 years old) was selected as a group of normal occlusion. From their gypsum cast, this conclusion was obtained. 1. Intra-observer measurement errors in buccolingual diameter, maxillary lateral incisors have somewhat bigger errors. In mesiodistal diameter, maxillary first molars and maxillary second molar have bigger numerical value. Mean errors of measurement are 0.051mm at buccolingual diameter of crown and 0.083mm at mesiodistal diameter. 2. Fluctuating asymmetry is 0.030 average in buccolingual diameter, and 0.037 average in mesiodistal diameter. Statistically there are no big differences. 3. Male has longer buccolingual diameter than female in every permanent teeth. Teeth which have statistical difference in buccolingual diameter are maxillary lateral incisor, maxillary canine, maxillary second molar, mandibular central incisor, mandibular canine, mandibular second premolar, and mandibular first molar. In mesiodistal diameter maxillary central incisor, maxillary canine, and mandibular first molar have statistically difference. 4. Tooth which has the biggest difference depending on gender is maxillary lateral incisor in buccolingual diameter and mandibular canine in mesiodistal diameter. 5. Both sexes have similar crown index. Male has bigger value of crown module measurement and crown area measurement in every tooth. Crown area considered as size of tooth from occlusal surface was bigger in male than in female statistically except some teeth, maxillary first premolar, mandibular lateral incisor, first premolar and second premolar.