• Conservation Science in Museum
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• v.26
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• pp.143-160
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• 2021

The Seoul Baekje Museum has been conducting excavations at the Ancient Tomb Complex in Seokchon-dong, Seoul (Historic Site No. 243), known to be tombs of the royal family and the ruling class during the Hanseong period of the Baekje Kingdom. In this study, gold earrings that were revealed during the excavation underwent scientific analysis and conservation treatment. Stereo microscopy, SEM, X-ray imaging, CT, and XRF were applied in the analysis, and the characteristics, internal structure, and composition of the earrings as well as their production method were investigated. The results confirmed that the main hoops of the gilt-bronze earrings were made of copper cores gilt using mercury amalgamation. The findings also revealed that the hexahedron in the middle pendant was made by connecting small rings using molten gold powder, and the pendant sphere at the end was formed by soldering two hemispheres. As for the two thin-hoop earrings, they showed similar surface compositions but were made using different methods, with one made from a copper core wrapped with a gold plate and the other made by bending a gold rod. The gold content varied depending on the item and the place of measurement, but overall the earrings showed a relatively high gold content of approximately 19 to 21K. The purity of the golden earrings and the sophisticated manufacturing techniques applied indicate the high status of the buried person and of the tomb complex in Seokchong-dong.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.162-176
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• 2022

In Lead-based reactor (LBR) severe accident, the meltdown and migration inside the reactor core will lead to fuel fragment concentration, which may further cause re-criticality and even core disintegration. Accurately predicting the migration and solidification behavior of melt in LBR severe accidents is of prime importance for safety analysis of LBR. In this study, the Moving Particle Semi-implicit (MPS) method is validated and used to simulate the migration and solidification behavior. Two main surface tension models are validated and compared. Meanwhile, the MPS method is validated by the L-plate solidification test. Based on the improved MPS method, the migration and solidification behavior of melt in LBR severe accident was studied furthermore. In the Pb-Bi coolant, the melt flows upward due to density difference. The migration and solidification behavior are greatly affected by the surface tension and viscous resistance varying with enthalpy. The whole movement process can be divided into three stages depending on the change in velocity. The heat transfer of core melt is determined jointly by two heat transfer modes: flow heat transfer and solid conductivity. Generally, the research results indicate that the MPS method has unique advantage in studying the migration and solidification behavior in LBR severe accident.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.3
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• pp.30-37
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• 2023

The PSCB girder bridge is a closed cross-section in which the top and bottom flanges and the web are integrated, and the structural characteristics are generally different from the bridges in which the girder and the floor plate are separated, so a maintenance plan that reflects the characteristics of the PSCB girder bridge is required. As a result of analyzing damage types by collecting detailed safety diagnosis reports of highway PSCB girder bridges, most of the deterioration and damage occurring during use is concentrated on the top flange. In particular, cracks in the bridge direction on the underside of the top flange occurred in about 70 % of the PSCB girder bridges to be analyzed, and these cracks were judged to be caused by indirect loads such as heat of hydration and drying shrinkage rather than structural cracks caused by external loads. In order to improve durability and reduce maintenance costs of PSCB girder bridges in use, it is necessary to control restraint drying shrinkage cracks from the design stage. Therefore, in this paper, the cracks caused by drying shrinkage under restraint, which is the main cause of cracks under the flanges of the top part of the PSCB girder bridge, were directly calculated using the Gilbert Model, and the influencing factors such as the amount of reinforcing bars, diameter and spacing of reinforcing bars were analyzed. As a result of the analysis, it was found that the crack width caused by restraint drying shrinkage exceeded the allowable crack width of 0.2 mm for reinforcing bars with a reinforcing bar ratio of 0.01 or less based on the H16 reinforcing bar and a reinforcing bar with a diameter greater than H19 based on the reinforcing bar ratio of 0.01. Finally, based on the results of the crack width review, a method for controlling the crack width of the top flange of the PSCB girder bridge was proposed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.1
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• pp.175-182
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• 2001

The main focus of this study was set to help college students in Kangwon province to improve and correct dietary habits and to maintain healthy life. The nutritional status and food preference of college students were examined from May to July, 1999. The collection of the research data has been made on the basis of questionnaries for 184 college students residing in Kangwon province. Statistical analysis of the data was performed using SAS package program for descriptive frequency and statistical significance. The meal skipping ratio of the subjects were 2% and for the reasons of meal skipping 45% responded "lack of time". As for main dishes, cooked rice turned out to be the most preferred by the subjects and the second and third favored by female students were bread and noodle respectively. Most preferred side-dishes were meat soup, kimchi, laver Kui,squid Bockeum, fried squid, beef Chon, squid Chorim, soy Namul, Dubuk Changachi and squid Muchim. Less preferred side-dishes include radish soup, white kimchi, mugwort fry, liver Bockeum, liver sheon and egg plant Kui. No one-plate food was disliked by the subjects. Male liked Manndukuk and female liked cuttle fish rice. The intakes of nutrient except for energy, iron and calcium for female students were the same or above the Recommended Dietary Allowances (RDA) for Koreans.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.33 no.3
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• pp.159-165
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• 1997

This paper presents the optimum dimension of 89 ton class stow-net vessel with stern-fishing. The model of basic design is developed by using the optimization techniques referring to objective function and numerous constraints as follows; speed, fishing quantity, fishing days, catch per unit effort(CPUE), and weight/ratio of main dimensions, etc. Thus, the basic design of stow-net fishing vessel is built up by using the optimization of the design variables called the economic optimization criteria, and the objective function represents the criterion which is cost benefit ratio(CBR). The main conclusions are as follows. 1. S/W for decision of optimum hull size is developed in 89 ton class stow-net fishing vessel which is constructed with optimization of the design variables called the economic optimization criteria. 2. For optimum ship dimensions in 89 ton class stow-net fishing vessel, the hull dimensions can be obtained in the range of L= 27.3m, B = 6.6m, D = 2.80m, Cb = 0.695, T/D = 0.80, $\Delta$(displacement)=281.7ton with 10 knots.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.129-136
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• 2011

Microorganisms are the main causative factors of pulpal and periapical diseases, therefore successful endodontic treatment is depend on the effective elimination of intracanal bacterial populations. Many studies have been reported antimicrobial effect of Allyl isothiocyanate (AIT) which the principle ingredient of Horseradish (Armoracia rusticana) root extracts. The purposes of this study are to evaluate the antimicrobial effectiveness of Horseradish root extracts against Enterococcus faecalis in root canals of extracted human teeth and compare to sodium hypochlorite (NaOCl). Extracted human mandibular premolar root canals were infected with E. faecalis for 21 days, and then irrigated with Horseradish root extracts, NaOCl solution and saline. After canal irrigation, first samples (S1) were taken. After first sampling, the canals were additionally incubated 7 days, and then second samples (S2) were taken. The samples were inoculated on EHI agar plate to determine the colony forming units (CFU). 1. Mean values of CFU in S1 were $5.815{\times}10^3$ CFU/ml at Horseradish groups, and $3.465{\times}10^3$ CFU/ml at NaOCI groups. There was no statistically significant differences (p=0.086). 2. Mean values of CFU in S2 were $3.100{\times}10^3$ CFU/ml at Horseradish groups, and $5.252{\times}10^5$ CFU/ml at NaOCI groups. There was statistically significant difference (p<.05). 3. There was no statistically significant differences (p=0.076) between S1 and S2 at Horseradish groups in the mean values of CFU. However, there was statistically significant differences (p<.05) between S1 and S2 at NaOCI groups in the mean values of CFU.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.83-94
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• 2011

Extra heavy oil reservoirs are distributed over the world but most of them is deposited in the northern part of the Orinoco River in Venezuela, in the area of 5,500 $km^2$, This region, which has been commonly called "the Orinoco Oil Belt", contains estimated 1.3 trillion barrels of original oil-in-place and 250 billion barrels of established reserves. The Venezuela extra heavy oil has an API gravity of less than 10 degree and in situ viscosity of 5,000 cP at reservoir condition. Although the presence of extra heavy oil in the Orinoco Oil Belt has been initially reported in the 1930's, the commercial development using in situ cold production started in the 1990's. The Orinoco heavy oil deposits are clustered into 4 development areas, Boyaco, Junin, Ayachoco, and Carabobo respectively, and they are subdivided into totally 31 production blocks. Nowadays, PDVSA (Petr$\'{o}$leos de Venzuela, S.A.) makes a development of each production block with the international oil companies from more than 20 countries forming a international joint-venture company. The Eastern Venezuela Basin, the Orinoco Oil Belt is included in, is one of the major oil-bearing sedimentary basins in Venezuela and is first formed as a passive margin basin by the Jurassic tectonic plate motion. The major source rock of heavy oil is the late Cretaceous calcareous shale in the central Eastern Venezuela Basin. Hydrocarbon materials migrated an average of 150 km up dip to the southern margin of the basin. During the migration, lighter fractions in the hydrocarbon were removed by biodegradation and the oil changed into heavy and/or extra heavy oil. Miocene Oficina Formation, the main extra heavy oil reservoir, is the unconsolidated sand and shale alternation formed in fluvial-estuarine environment and also has irregularly a large number of the Cenozoic faults induced by basin subsidence and tectonics. Because Oficina Formation has not only complex lithology distribution but also irregular geology structure, geological evolution and characteristics of the reservoirs have to be determined for economical production well design and effective oil recovery. This study introduces geological formation and evolution of the Venezuela extra heavy oil reservoirs and suggest their significant geological characteristics which are (1) thickness and geometry of reservoir pay sands, (2) continuity and thickness of mud beds, (3) geometry of faults, (4) depth and geothermal character of reservoir, (5) in-situ stress field of reservoir, and (6) chemical composition of extra heavy oil. Newly developed exploration techniques, such as 3-D seismic survey and LWD (logging while drilling), can be expected as powerful methods to recognize the geological reservoir characteristics in the Orinoco Oil Belt.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.24 no.2
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• pp.78-82
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• 1988

Near sea trawlers of Korea sometimes catch pelagic fishes like file fish by using midwater trawl gear even though usually catch bottom fish. It is reasonable to use the specific otter board as well as specific net in bottom trawling and in midwater trawling respectively. But, the trawlers are so small ranging 100 to 120GT, 700 to 100ps that it is very complicated to use different otter board for bottom trawling and for midwater trawling. The otter board for bottom trawling. is also used for the midwater trawling without any change even though the net is changed into the specific one. Although the otter board in the midwater trawling should be lighter than that for bottom trawling, to use otter board for bottom trawling directly for the midwater trawling without any change makes the net easily touch the sea bed and also make the horizontal opening of the otter boards be limited owing to the length of warp in the southern sea of Korea, main fishing ground of midwater trawling, which is 100m or so in depth. That is why the otter board for the midwater trawling should be made lighter than that in the bottom trawling, even if temporary. The authors carried out an experiment to achieve this purpose by attaching a large styropol float on the top of the otter board. In this experiment, underwater weight of the otter board was 630kg and buoyancy of the float was 510kg. To determine the depth and horizontal opening of the otter board, two fish finder was used. A transmitter of 50KHz fish finder was set downward through the shoe plate of otter board to determine the elevation of otter board from the sea bed, and a transmitter of 200KHz fish finder was set sideways on the starboard otter board to be able to detect the distance between otter boards. The obtained results can be summarized as follows: 1. The actual towing speed in the experiment varied 1.1 to 1.8 m/sec. 2. The depth of otter board was within 41 to 25m with float on the top and 45 to 26m without float in case of the warp length 100m, whereas the depth 68-44m with float and 74-46m without float in case of the warp length 150m. This fact means that the depth with float was 9-4% shallower than that without float. 3. The horizontal opening between otter boards was within 34-41m with float and 30-38m without float in case of the warp length 100m, whereas the opening was 44-50m with float and 37-46m without float in case of the warp length 150m. This fact means the opening with float was 10% greater than that without float in case of the warp length 100m, and 15% greater in case of the warp length 150m. 4. The horizontal opening between wing tips by using the otter board with float was 1m greater than by without float in case of the warp length 100m, whereas the opening by with float was 2m greater than by without float in case of warp length 150m. From this fact, it can be estimated that the effective opening area of the net mouth by using the otter board with float could be made 10% greater than by without float in case of warp length 100m, whereas the area with float 20% greater than by without float in case of warp length 150m.

• Journal of Food Hygiene and Safety
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• v.20 no.4
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• pp.244-252
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• 2005

This study was performed far development of new analytical method of beet red in foods. In this study, analysis of beet red in foods has been carried out by detection of betanine and isobetanine, the main color component of beet red as indicator compounds. The qualitative analysis technique consisted of clean-up of the colors with a $C_{18}$ cartridge, separation of the colors by cellulose TLC plate using acetone:3-methyl-1-butanol:distilled water (7:7:6) as a solvent system. Also, the quantitative analysis was performed using X-terra RP at wavelength 538 nm and $0.1\%$ phosphoric acid : methanol (90:10) as a solvent. The quantitative results of beet .ed were as follows:900.22$\∼$27701.60 $\mu$g/g for 60 item in nutrient supplement food, $21.95\∼713.40{\mu}g/g$ for 30 items and N.D. for 18 items in cindy, and $155.85{\∼}505.37{\mu}g/g$ for 12 items in ice creams, $43.52\∼64.75{\mu}g/g$ for 18 items and N.D. for 54 item in sauce, N.D. for 12 items in retort food.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.4
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• pp.299-305
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• 2010

Purpose: Adipose tissue is located beneath the skin, around internal organs, and in the bone marrow in humans. Its main role is to store energy in the form of fat, although it also cushions and insulates the body. Adipose tissue also has the ability to dynamically expand and shrink throughout the life of an adult. Recently, it has been shown that adipose tissue contains a population of adult multipotent mesenchymal stem cells and endothelial progenitor cells that, in cell culture conditions, have extensive proliferative capacity and are able to differentiate into several lineages, including, osteogenic, chondrogenic, endothelial cells, and myogenic lineages. Materials and Methods: This study focused on endothelial cell culture from the adipose tissue. Adipose tissues were harvested from buccal fat pad during bilateral sagittal split ramus osteotomy for surgical correction of mandibular prognathism. The tissues were treated with 0.075% type I collagenase. The samples were neutralized with DMEM/and centrifuged for 10 min at 2,400 rpm. The pellet was treated with 3 volume of RBC lysis buffer and filtered through a 100 ${\mu}m$ nylon cell strainer. The filtered cells were centrifuged for 10 min at 2,400 rpm. The cells were further cultured in the endothelial cell culture medium (EGM-2, Cambrex, Walkersville, Md., USA) supplemented with 10% fetal bovine serum, human EGF, human VEGF, human insulin-like growth factor-1, human FGF-$\beta$, heparin, ascorbic acid and hydrocortisone at a density of $1{\times}10^5$ cells/well in a 24-well plate. Low positivity of endothelial cell markers, such as CD31 and CD146, was observed during early passage of cells. Results: Increase of CD146 positivity was observed in passage 5 to 7 adipose tissue-derived cells. However, CD44, representative mesenchymal stem cell marker, was also strongly expressed. CD146 sorted adipose tissue-derived cells was cultured using immuno-magnetic beads. Magnetic labeling with 100 ${\mu}l$ microbeads per 108 cells was performed for 30 minutes at $4^{\circ}C$ a using CD146 direct cell isolation kit. Magnetic separation was carried out and a separator under a biological hood. Aliquous of CD146+ sorted cells were evaluated for purity by flow cytometry. Sorted cells were 96.04% positivity for CD146. And then tube formation was examined. These CD146 sorted adipose tissue-derived cells formed tube-like structures on Matrigel. Conclusion: These results suggest that adipose tissue-derived cells are endothelial cells. With the fabrication of the vascularized scaffold construct, novel approaches could be developed to enhance the engineered scaffold by the addition of adipose tissue-derived endothelial cells and periosteal-derived osteoblastic cells to promote bone growth.