• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.75-76
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• 2007

A mis-handling of the ship operators show high rate among the whole marine accidents. Since the port conditions have been getting worse. also as her size and speed increase, collision risk has been increased so that ship needs the automatic control system for collision. From that purpose, this research has been proceeded. The research has based on the MMG mathematical model, used Surge-Sway-Yaw motion equation, the information from the position and estimated time of collision point (DCPA and TCPA) to determine the collision risk with Fuzzy theory. To verify this system, ship was simulated when the ship encountered multitude of ships around the coast. The simulation result shows good application in avoiding ship collisions around the coast.

• Wind and Structures
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• v.30 no.5
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• pp.533-546
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• 2020

Large Eddy Simulation (LES) is used to study the effects of steady slot suction on the aerodynamic forces of and flow around a wall-mounted finite-length square cylinder. The aspect ratio H/d of the tested cylinder is 5, where H and d are the cylinder height and width, respectively. The Reynolds number based on free-stream oncoming flow velocity U_∞ and d is 2.78×10⁴. The suction slot locates near the leading edge of the free end, with a width of 0.025d and a length of 0.9d. The suction coefficient Q (= U_s/U_∞) is varied as Q = 0, 1 and 3, where U_s is the velocity at the entrance of the suction slot. It is found that the free-end steady slot suction can effectively suppress the aerodynamic forces of the model. The maximum reduction of aerodynamic forces occurs at Q = 1, with the time-mean drag, fluctuating drag, and fluctuating lift reduced by 3.75%, 19.08%, 40.91%, respectively. For Q = 3, all aerodynamic forces are still smaller than those for Q = 0 (uncontrolled case), but obviously higher than those for Q = 1. The involved control mechanism is successfully revealed, based on the comparison of the flow around cylinder free end and the near wake for the three tested Q values.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.4
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• pp.221-230
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• 2012

Objectives: This study sought to evaluate the efficacy of collagen graft materials, as compared to other graft materials, for use in healing calvarial defects in rabbits. Materials and Methods: Ten mm diameter calvarial defects were made in ten rabbits. The rabbits were then divided into 4 groups: control, autogenous bone graft, SureOss graft, and Teruplug graft. Bone regeneration was evaluated using histological and radiographic methods. Results: Based on visual examination, no distinct healing profile was observed. At 4 weeks after treatment, histological analysis showed there was no bone regeneration in the control group; however, at 8 weeks after treatment, new bone formation was observed around the margin of the defective sites. In the autogenous bone graft group, new bone formation was observed at 4 weeks after treatment and mature bone was detected around the grafted bone after 8 weeks. In the SureOss graft group, at 4 weeks after treatment, acute inflammatory and multinuclear cells were noted around the grafted materials; at 8 weeks after treatment, a decrease in graft materials coupled with new bone formation were observed at the defective sites. In the Teruplug graft group, new bone formation was detected surrounding the bone margin and without signs of inflammation. There were statistically significant differences observed between the graft and control group in terms of bone density as evidenced by radiographic analysis using computed tomography (P<0.05), particularly for the autogenous bone graft group (P<0.001). Conclusion: These results suggested that autogenous bone, SureOss and Teruplug have the ability to induce bone regeneration as compared to an untreated control group. The osteogenic potential of Teruplug was observed to be lower than that of autogenous bone, but similar to that of SureOss.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.544-547
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• 2003

The objective of this study is to investigate the contamination levels and dispersion patterns of arsenic and heavy metals and to estimate the bioaccessible fraction of the metals in soil and plant samples in the vicinity of the abandoned Songcheon Au-Ag mine. Tailings, soils, plants (Chinese cabbage, red pepper, soybean, radish, sesame leaves, green onion, lettuce, potato leaves, angelica and groundsel) and waters were collected around the mine site. After appropriate preparation, all samples were analyzed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of As and heavy metals were found in tailings. Mean concentrations of As in agricultural soils were higher than the permissible level. Especially, maximum level of As in farmland soil was 513 mg/kg. The highest concentrations of As and Zn were found in Chinese cabbage (6.7 mg/kg and 359 mg/kg, respectively). Concentrations of As, Cd, and Zn in most stream waters which are used for drinking water around this mine area were higher than the permissible levels regulated in Korea. Maximum levels of As, Cd and Zn in stream waters were 0.78 mg/L, 0.19 mg/L and 5.4 mg/L, respectively. These results indicate that mine tailings can be the main contamination sources of As and heavy metals in the soil-water system in the mine area. The average of estimated bioaccessible fraction of As in farmland soils were $3.7\%$ (in simulated stomach) and $10.8\%$ (in simulated small intestine). The highest value of bioaccessible fraction of metal in farmland soils was $46.5\%$ for Cd.

• Applied Microscopy
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• v.27 no.3
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• pp.321-332
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• 1997

The dermal papilla is known to playa major role in influencing the form and dynamics of the hair follicle, which probably involves regulatory substances crossing the basal lamina. But little is known about the junctions between the dermal papilla and the surrounding epithelial cells of the hair bulb, or between the connective tissue and the epithelial cells on the outside of the hair follicle. This study was performed to identify the ultrastructural differences between dermoepidermal junction of the skin and connective tissue-epithelial junctions on the outside of the hair follicle and around the dermal papilla of normal anagen hair follicles in the human fetal scalp skin. Electron microscopic findings of dermoepidermal junction in scalp skin showed that basal lamina was very irregular and undulated, and it contained many attachment plaques of hemidesmosomes with sub-basal dense plates, tonofilaments, and anchoring filaments. Also invaginations of plasma membrane of basal keratinocytes were seen. There were clear differences both on the outside of the follicle and around the dermal papilla as compared with similar junction in the skin. In particular, neither hemidesmosomes nor tonofilaments, as seen in dermoepidermal junction, were observed in the dermal papilla. Also attachment plaque, sub-basal dense plate and anchoring filaments were not observed at the junction on the outside of the follicle and the dermal papilla. There were some differences between connective tissue-epithelial junctions on the outside of the hair follicle and around the dermal papilla, ie, smoothness of basal lamina and orthogonal arrangement of collagen fibers were seen in the outside of hair follicle, but not in the dermal papilla. These results indicate that the mechanical connection between the hair follicle and the connective tissue component is much weaker than that between the corresponding components in skin, and it reflects the dynamic processes during the anagen phase of the hair follicle compared to the relatively permanent state of the epidermis.

• Journal of Embryo Transfer
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• v.33 no.2
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• pp.61-68
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• 2018

The major focus of this study is to analyze the expression of bovine MMPs and to monitor their activity during the estrus cycle and pregnancy. During pregnancy, MMP-2 expression was detectable around 30 days but became insignificant by 60 days, then started to increase again around 90 days and reached the maximum at 250 days. The activity of MMP-2 protein changed in accordance with its expression level. As expected, the level of TIMP-2 exhibited a reverse pattern. About MMP-9, high level expression was observed as early as 30 days and gradually increase until 90 days. Then started to decrease after 250 days. Again, the sites of MMP-9 expression were similar to those of MMP-2. On the other hand, expression of TIMP-3 remained low until 90 days but showed a small and temporal increase around 250 days. In summary, expression of different MMPs were differentially regulated during estrus cycle and pregnancy. While the expression of MMP-2 was high in estrus cycle, MMP-9 slowly takes over with the progression of pregnancy. These results indicated that the luteal tissue perform distinct functions during pregnancy and estrus. Perhaps the activity of MMP-2 is required for the structural remodeling of luteum, resulting the suppression of P4 inflow from blood. On the other hand, steady maintenance of MMP-9 throughout luteal development is important for the activation of cell proliferation, maturation and angiogenesis.

• Mycobiology
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• v.28 no.1
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• pp.27-32
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• 2000

The ectomycorrhizal roots were collected from the soils around the bases of basidiocarps of the four edible mushrooms in the stands of Pinus densiflora or Querus acutissima communities (Mt. Wol-Ak in Eastern Chung-Puk): The basidiocarps of Tricholoma matsutake (TM), Sarcodon asparatus (SA), S. imbricatum (SI), and Polyozellus multiplex (PM) are usually collected. The ectomycorrhizal roots of TM, PM and SI were related to the roots of P. densiflora, but the other to the roots of Q. acutissima in Korea. Particularly, the basidiocarps of PM were collected in the mixed stand of both P. densiflora and Q. acutissima. The morphologies of the ectomycorrhizal roots were observed to be the yellowish brown coral (dichromatous) or pyramid types in the roots of the pine, but dark brown un-branched sticks (roots) in the ends of ectomycorrhizal roots of Querus plants. The un-branched roots were covered with the dark mycelia (rhizomorph) around them. Therefore, the ectomyorrhizal roots of PM were observed to have two kinds of types; The single blackish un-branched roots were observed to be attached to the yellowish coral type roots. The bundles of TM mycelia were filled with cortical cells (in the roots of P. densiflora), but the mycelia of the other fungi (Aphylloporales) were massed between the cortical cells of P. densiflora or Q. acutissima. Their anatomical and gross features were considered to be simailar but very important in the ectomycorrhizal roots for these edible mushrooms.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.10
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• pp.670-677
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• 2011

Direct numerical simulation are performed in order to investigate the effect of the circular cylinder shape on the forced convection around a circular cylinder at the Reynolds number of 300 and Prandtl number of 0.71. Three-dimensional characteristics of fluid flow and heat transfer around the smooth, wavy and torsional cylinders are investigated. A wavy cylinder has the sinusoidal variation in the cross sectional area along the spanwise direction with the wave length of ${\pi}/3$ and wavy amplitude of 0.1. A torsional cylinder has the twisted elliptic cross section with a torsional period of ${\pi}/2$ and an axis ratio of 1.35 corresponding to the major axis of 1.15 and the minor axis of 0.85. The value of time-and surface-averaged drag coefficient for the smooth cylinder is similar to that for the wavy cylinder, but larger than that for the torsional cylinder. The time and surface-averaged lift coefficient for the smooth cylinder is larger than that for the wavy and torsional cylinders. The time-averaged local heat transfer rate for the wavy and torsional cylinders shows different distribution along the circumferential direction, compared to that for the smooth cylinder because of the shape change in the spanwise direction for the cases of the wavy and torsional cylinders.

• Atmosphere
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• v.31 no.2
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• pp.215-227
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• 2021

The necessity of the prediction on the Seasonal-to-Subseasonal (S2S) timescale continues to rise. It led a series of studies on the S2S prediction models, including the Global Seasonal Forecasting System Version 5 (GloSea5) of the Korea Meteorological Administration. By extending previous studies, the present study documents sea surface temperature (SST) prediction skill around the Korean peninsula in the GloSea5 hindcast over the period of 1991~2010. The overall SST prediction skill is about a week except for the regions where SST is not well captured at the initialized date. This limited prediction skill is partly due to the model mean biases which vary substantially from season to season. When such biases are systematically removed on daily and seasonal time scales the SST prediction skill is improved to 15 days. This improvement is mostly due to the reduced error associated with internal SST variability during model integrations. This result suggests that SST around the Korean peninsula can be reliably predicted with appropriate post-processing.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.4
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• pp.66-73
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• 2009

Temperature phase anaerobic co-digestion process was conducted with the one to one mixture of food wastewater with livestock wastewater, and the presence and the dynamics of various pathogenic microorganisms was analyzed. The mixture contained various enteric and pathogenic bacteria, such as Escherichia coli. Enterobacteriaceae, Coliform bacteria. Staphylococcus aureus, Salmonella, Shigella, Listeria, and Yeast. Anaerobic digestion has become stabilized around 21 days after the reaction started, showing about 80% to 90% of remarkable reduction rates of microorganisms until this period in acidogenic reactor (AR) and methanogenic reactor (MR), respect ively. After stabilization, the average reduction rate of organic matter was recorded as around 60% in MR. Most microorganisms in the effluent were not detected at around the last period of the reaction, except Listeria and S. aureus, which showed the growth even at the last day of the reaction.