• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.152-159
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• 2022

The role of the posterior palatal seal is important in retention of the maxillary complete denture. After taking the final impression, additional retention can be given to the maxillary denture through a mechanical method of forming a groove on master cast, but this is often overlooked in the clinical process. As a result, the posterior palatal seal is formed in a uniform way by the technician without considering the individual characteristics of the patient. Until now, various types of posterior palatal seal have been introduced by many people. This case report describes the process of manufacturing the maxillary complete denture by determining the position and form of an appropriate posterior palatal seal after considering the patient's anatomical palatal form and tissue displacement during function.

• Journal of Practical Agriculture & Fisheries Research
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• v.22 no.1
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• pp.55-63
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• 2020

This study aimed to investigate responses of plant growth and photosynthesis to different kinds of covering materials with selective light transmit for red leaf lettuce (Lactuca sativa L.). Experimental pot design was attached UV blocking filter, red filter, blue filter, and green filter. The kinds of covering materials showed significant results for plant growth especially control, UV blocking filter, and red filter. The photosynthetic rate and anthocyanin content of red leaf lettuce were higher in control and UV blocking filter than others. The quality of red leaf lettuce was low in red, green, and blue film treatments because of too low anthocyanin content.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.157-164
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• 2021

Recently, a number of studies have been conducted on photocatalysts and adsorbents that can remove harmful substances to improve environmental problems related to fine particles. In this study, a porous foam composites were fabricated using palm-based activated carbon having a large amount of micro-pores and foam concrete with a significantly larger total pore volume compared to general construction materials. To evaluate the adsorption potential of fine particles, the pore structure of the foam composites were analyzed. For the analysis of the pore structure of the foam composite, BET and Harkins-jura theory were applied from the measured nitrogen adsorption isotherm. From the results of the analysis, the specific surface area and micro-pore volume of the foam composite containing activated carbon increased significantly compared to Plain. As thereplacement of activated carbon increased, the specific surface area and micro-pore volume of the foam composite tended to increase. It seems that the foam composite has high adsorption performance for gaseous fine particle precursor such as nitrogen oxides.

• Journal of Conservation Science
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• v.37 no.6
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• pp.767-777
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• 2021

This study analyzed the microstructures and chemical composition of three samples of bronze mirrors excavated in the Jeollanam-do region, particularly Goheung and Damyang. Under x-ray irradiation, the analysis results confirmed the broken parts and pores caused by cracks, casting, and corrosion. Major and minor elemental analysis were performed on three mirrors by Scanning electron microscopy (SEM) with Energy dispersive x-ray spectrometry (EDS) and Inductively coupled plasma mass spe ctrome try (ICP-MS). The re sult shows that the bronze mirrors containe d Cu-Sn-Pb alloys. Alpha phase and eutectic phase were observed in the microstructure, confirming that the casting was performed without additional heat treatment. Notably, Three bronze mirrors were made early Three Kingdoms period in Korea.

• Clean Technology
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• v.15 no.2
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• pp.122-129
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• 2009

The effect of calcination temperature or hydrothermal treatment of commercial Fe-beta zeolites in the range of $450{\sim}900^{\circ}C$ were examined in the direct decomposition of $N_2O$. Fe-beta zeolites used were characterized using XRD, $N_2$ sorption, $^{27}Al$ MAS NMR and XPS. Although the surface area and micropore volume of Fe-beta zeolite after calcination at $900^{\circ}C$ and hydrothermal treatment at $750^{\circ}C$ decreased ca. 30%, a larger decrease in the surface area and micropore volume by hydrothermal treatment was observed than by calcination treatment alone. However, the Al sites in frameworks of zeolite were conserved in stable tetrahedral form resulting from low degree of dealumination which was related to the adjacent Fe ions on the Al sites. This could likely be correlated with the conservation of high surface area and micropore volume of Fe-beta zeolites. The increase in the calcination or hydrothermal treatment temperature caused the increase of decomposition temperature of $N_2O$ and the severe deactivation was observed after hydrothermal treatment than calcination treatment.

• The Research Journal of the Costume Culture
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• v.31 no.1
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• pp.107-123
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• 2023

This research studied the electrical characteristics, IR transmission characteristics, stealth functions, and thermal characteristics of infrared thermal-imaging cameras of copper-sputtered samples. Nylon samples were prepared for each density as a base material for copper-sputtering treatment. Copper-sputtered NFi, NM1, NM2, NM3, NM4, and NM5, showed electrical resistance of 0.8, 445.7, 80.7, 29.7, 0.3, and 2.2 Ω, respectively, all of which are very low values; for the mesh sample, the lower the density, the lower the electrical resistance. Measuring the IR transmittance showed that the infrared transmittance of the copper-sputtered samples was significantly reduced compared to the untreated sample. Compared to the untreated samples, the transmittance went from 92.0-64.1%. When copper sputtered surface was directed to the IR irradiator, the IR transmittance went from 73.5 to 43.8%. As the density of the sample increased, the transmittance tended to decreased. After the infrared thermal imaging, the absolute values of △R, △G, and △B of the copper phase increased from 2 to 167, 98 to 192, and 7 to 118, respectively, and the closer the density of the sample (NM5→NFi), the larger the absolute value. This proves that the dense copper phase-up sample has a stealth effect on the infrared thermal imaging camera. It is believed that the copper-sputtered nylon samples produced in this study have applications in multifunctional uniforms, bio-signal detection sensors, stage costumes, etc.

• The Journal of the Convergence on Culture Technology
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• v.9 no.6
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• pp.1049-1055
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• 2023

The utilization of agricultural drones for pest control operations has been increasing due to its economic efficiency. However, variations in the effectiveness of these operations occur depending on the operator's proficiency. In this study, we applied a smart operating mode to overcome the limitations of manual flight mode and proposed a numerical model. Through comparative validation with prior research, we conducted experimental verification. As a result, we determined the spray time and calculation of spray area for each drone model. We selected a drone for pest control with a high similarity to the numerical model and verified it experimentally. Through this, we confirmed that the application of the smart operating mode is more effective in terms of calculation of spray area and operational efficiency compared to manual flight mode.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.116-122
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• 2023

As the number of hydrogen filling stations for hydrogen supply increases with the progress of low-carbon eco-friendly energy policies, the risk of accidents is also increasing. Actual pressure vessels may have defects such as notches, pores, and inclusions that may occur during the manufacturing process. Therefore, it is necessary to evaluate the integrity of pressure vessels in the case where cracks exist in pressure vessels under internal pressure. In this paper, 3D finite element analysis was used to evaluate the structural safety of hydrogen-filled pressure vessels with surface cracks, and the shape of surface cracks was compared with the commonly used semi-elliptical shape. In the future, these results will be used to predict the remaining life of the pressure vessel in consideration of fracture mechanics.

• Clean Technology
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• v.30 no.3
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• pp.248-257
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• 2024

Carbon dioxide is an undesired component of biogas and landfill gas. As a result, it needs to be removed from these mixtures in order to increase their heating value and reduce corrosion during treatment. Zeolites are a class of microporous materials that can be used as adsorbents for the separation of carbon dioxide from gas mixtures. In this work, the pure gas adsorption isotherms of methane and carbon dioxide and the selectivity of their mixture onto LTA-4A, FAU-13X and FAU-NaY adsorbents at temperatures of 273, 298 and 323 K and pressures up to 30 bars were calculated by the Monte Carlo method. Also, the influence of a flexible framework in a set of zeolites on the separation of methane and carbon dioxide was studied. Carbon dioxide adsorption onto the zeolites used in this work was more favorable than methane adsorption. The FAU-13X adsorbent had the highest adsorption capacity among the studied adsorbents. However, the selectivity of carbon dioxide over methane for LTA-4A was the highest. The adsorption capacities of a rigid framework were higher than those of a flexible framework. The influence of the framework flexibility in FAU on adsorption capacity was small. In contrast, its influence on selectivity seemed to be much larger.

• Korean Journal of Plant Resources
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• v.20 no.1
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• pp.43-49
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• 2007

This study was conducted to examine the pattern and characteristics of flowering and leaf emergence for twenty two kinds of the genus of Lycoris sp. One species of Lycoris was flowered on July to August, twelve species on August, and nine species on September. Shape of flowers were as follows : Nine species belong to L. radiara-shaped flower, seven species L. squamigera-shaped flower, and seven species the intermediate type. Flower color of three kind were an order of descent red and pink. seven kind white, four kind yellow, three kind orange, and two kind purple colors. Ten Lycoris species were good fertile, and two kinds were poor fertile. The average length of pollen grain was ranged from $48.53\;to\;88.62{\mu}m$, and the width from $22.87\;to\;33.67{\mu}m$. Eleven kinds were spring-leaf emergence type, and ten kind autumn-leaf emergence types. Hunter values in leaves were as follows : $L^*$ value was ranged from 31.6 to 45.2; $a^*$ values from -6.74 to -17.46; $b^*$ values from 6.19 to 21.89 Leaf width was ranged from 0.90 to 2.35cm, and its shape was oblong. The length of epidermal cells was 0.33 to 0.75mm, and the width was $38.53\;to\;90.00{\mu}m$. Most of stomata were distributed in the back side of leaves. The length of stomata was ranged from $67.12\;to\;104.89{\mu}m$, and its width was from $14.90\;to\;71.52{\mu}m$.