• 한국해양학회지
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• v.22 no.1
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• pp.43-56
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• 1987

A study on sedimentation, geochemical behavior and seismic stratigrapht of the continental shelf sediments along the Korea Strait and a part of south and southeast offshore area of the Korea Peninsula was carried out. In the inner shelf floor with depth ranging up to 80m zonal distribution patterns of mud, sandy silt, and silty sand were observed. In the outer shelf, however, coarse sandy sediments are dominant, and shills and gravels were frequently observed. These observations seem to confirm the Holocene sedimentary processes on the continental shelves off the south, south to east coasts of Korea discussed by Park (1985 and 1986) and Park and Choi (1986). The suface sediments (upper most 5cm thick)from selected 9 stations were analyzed for Al,Mn, Fe,Cr,Ni,Cu,Zn and Pb in order to study geochemical behavior of the sediments in the study area. All data were normalized to Al to com,pensate the size effect of the sediments.In general,inner shelf sediments show slight enrichment compared to the outer shelf sediments.In particular,Pb and Zn show heavy enrichment in most of the sediments.to degrees comparable to those observed at the polluted Kwangyang and Masan Bay sediments.Thus,it is considered that rapid migration or movement of fine-grained sediments in the study area does exist. Three seismic stratigraphic units were analyzed based on the seismic records.The acoustic basement the lower sedimentary deposit(B)and the upper deposit(A)were observed.The strong reflectivity R,in particular, between unit A and B is considered to be an erosinal unconformity during the last Glacial time.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.3
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• pp.161-170
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• 2012

To provide domestic values of input parameters in a safety assessment of radioactive waste disposal under domestic deep underground environments, various kinds of experiments have been carried out under KURT (KAERI Underground Research Tunnel) conditions. The input parameters were classified, and some of them were selected for this study by the criteria of importance. The domestic experimental data under KURT environments were given top priority in the data review process. Foreign data under similar conditions to KURT were also gathered. The collected data were arranged and the statistical calculations were processed. The properties and distribution of the data were explained and compared to foreign values in view of their validity. The following parameters were analysed: failure time and early time failure rate of a container, solubility of nuclides, porosity and density of the buffer, and distribution coefficients of nuclides in the geomedia, hydraulic conductivity, diffusion depth of nuclides, groundwater flow rate, fracture aperture, length of internal fracture, and width of faulted rock mass in the host rock.

• Journal of Korea Water Resources Association
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• v.41 no.4
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• pp.423-432
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• 2008

The local migration or movement behavior of fishes in streams are related to feeding, spawning, growing, dispersing, and refuging. The pale chub (Zacco platypus) is a dominant species that migrates locally and inhabits in river and stream in Korea. However, dams, weirs, culverts and other regulatory structures are physical barriers that limit fish movement and fragment habits and populations. If main stream and off-channel habitats are connected with culverts, they would restrict the small fish as pale chub movement due to the high flow velocities and low depths. But in Korea, there is no experimental study to evaluate the swimming performance of species in Korea. Therefore, it is difficult to proposed that design guidelines for pass fishes through culverts. The purpose of this experimental study is to evaluate the swimming performance of pale chubs. A series of swimming performance test has been used in both of the fixed velocity and the incremental velocity methods in an experimental flume. As a result, the critical swimming speed for pale chub(body length 8.9 cm) was found to be about 0.7 m/s. Therefore, the flow velocity for culvert design in the low flow condition should not be exceed the its swimming ability, especially 0.7 m/s for pale chubs(body length 8.9 cm). And the minimum depth for culvert design in the low flow condition should not be lower than the fish body height add a dorsal fin height.

• Journal of the Mineralogical Society of Korea
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• v.20 no.3
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• pp.165-173
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• 2007

The KAERI Underground Research Tunnel (KURT) located in KAERI (Korea Atomic Energy Research Institute) was recently constructed following the site investigation in 2003. Its dimension is 180 m in length, 6 m in width, and 6 m in height, and it has a horseshoe-like cross-sec-lion and is located in the ground to the depth of 90 m. When the tunnel was dug into the ground with 100 m in length, fresh rocks, weathered rocks and fracture-filling materials were taken and examined by mineralogical and chemical analyses. There are phyllosilicate minerals such as illite, smectite and chlorite including calcite, which are filling some faults and cracks of the KURT rock. The illite and smectite usually coexist in the fracture, where their content ratio is different according to which mineral is predominant. There are high concentrations of U and Th in the rocks coated with iron-oxides and filled with secondary materials as compared with those in the fresh rocks. It seems that the radionuclides, which are slowly leached from the parent rocks or exist as a dissolved form in the groundwater and hydrothermal solution, may have been migrated along the fractures and thereafter selectively sorbed and coprecipitated on the iron-oxides and the fracture-filling materials. These results will be very useful far the evaluation of environmental factors affecting the nuclides migration and retardation when long-term safety is considered to the geological disposal of high-level radioactive wastes in the future.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.3
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• pp.32-39
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• 2009

In this paper, system optimization design technique of an impulse ground penetrating image radar (GPIR) in time domain is proposed to improve depth resolution of the system. For the purpose, time domain analysis method of key components such as impulse generator and UWB antenna is explained and by simulation, parameters of each component are determined. In particular, by standardizing the impulse signal, spectrum efficiency of a radiated impulse signal is improved and a U-shaped planar dipole antenna for a UWB antenna is developed. By equipping a parabolic metal reflector with the proposed antenna, external noise is prevented and the ability of radiating an input impulse into ground is improved. In addition, to remove ringing effect of the propose antenna which causes serious degradation of the system performance, resistors are loaded at the edge of the antenna and then Tx and Rx UWB antennas are optimized by simulation in time domain. For images of targets buried under the ground migration technique is applied and influence of tough ground surface on distortion of received impulse signals is reduced using technique of noise and signal distortion reduction in time domain and its time resolution is enhanced. To verify the design optimization procedure, a prototype of an GPIR and an artificial test field are made. Measurement results show that the resolution of the system designed is as good as that of a theoretical model.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.767-783
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• 1997

Guided tissue regeneration, bone graft procedures, and application of growth factors have been used to regenerate lost periodontal tissues. Recently, enamel matrix derivative has been introduced into periodontal regeneration procedures in expectation of promoting new bone and cementum formation. The purpose' of this study was to evaluate the effect of enamel matrix derivative in 1-wall intrabony defects in beagle dogs. For this purpose, each dog was anesthesized using intravenous anesthesia and mandibular 1st, 3rd premolars were extracted. 2 months later, the 1-wall intrabony defects(mesio-distal width: 4mm, depth: 4mm) were created on the distal side of 2nd premolars and mesial side of 4th premolars. The control group was treated with debridement alone, and experimental group was treated with debridement and enamel matrix derivative application. The healing processes were histologically and histometrically observed after 8 weeks and the results were as follows : 1. The length of junctional epithelium was $0.94{\pm}0.80mm$ in the control group, $0.57{\pm}0.42mm$ in the experimental group, with no statistically significant difference between groups. 2. The connective tissue attachment was $1.36{\pm}0.98mm$ in the control group. $0.38{\pm}0.43mm$ in the experimental group, with statistically significant difference between groups(P<0.05). 3. The new cementum formation was $2.49{\pm}1.06mm$ in the control group, $3.59{\pm}0.74mm$ in the experimental group. with statistically significant difference between groups(P<0.05). 4. The new bone formation was $1.92{\pm}0.97mm$ in the control group, $2.32{\pm}0.59mm$ in the experimental group. with no statistically significant difference between groups. Within the limitation to this study protocol, enamel matrix derivative application in 1-wall intrabony defect enhanced new cementum formation. Although there was no statistically significant difference, enamel matrix derivative also seems to be effective in inhibition of apical migration of junctional epithelium and new bone formation.

• Journal of the Mineralogical Society of Korea
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• v.24 no.3
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• pp.179-188
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• 2011

In order to investigate absolute age of marine sediment in the KR5 region, northeastern Pacific, we measured the Be isotope ($^{10}Be$ and $^{9}Be$) of box core (BC08-02-13) sediment with depth. Core sediment is divided into three sedimentary facies (Facies I, Facies II, FaciesIII). Facies I mainly consists of brown to dark brown (10YR4/3) homogeneous mud with high water content. Facies II shows brownish yellow (10YR6/6) color. The unconformity is recognized at the boundary between Facies I and Facies II, Facies III consists of very dark brown (10YR2/2) mud. Many bioturbated burrows are observed at FaciesII and FaciesIII. Based on Be dating results, FaciesIII and Facies II had been deposited before 3.7 Ma and 2.3 Ma, respectively. After 2.3 Ma, the upper part of Facies II was eroded due to the change of sedimenary environment. Facies I has been deposited since 1.8 Ma. The unconformity located at the boundary between Facies I and Facies II may be driven by the envrionmental change due to the migration of Intertropical Convergence Zone.

• Journal of Radiation Protection and Research
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• v.29 no.3
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• pp.197-204
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• 2004

Vertical distributions of $^{137}Cs\;and\;^{90}Sr$ activities are studied for the soils of six areas, Korea (Gori, Yeonggwang, Uljin, Weolseong, Goseong and Jeju). The soils from 6 areas are at geographically different locations with the different environmental conditions and parent rook. The activities of $^{137}Cs\;and\;^{90}Sr$ vary N.D.(below detection limit) to 185 Bq/kg and 2.79 - 8.06 Bq/kg, respectively. Activities of $^{137}Cs\;and\;^{90}Sr$ show the highest value at the surface soil and decrease with depth. $^{137}Cs$ activities at the top surface soils are positively correlated with annual precipitation and organic carbon content with little relationship with mean grain size and the clay content. The highest $^{137}Cs$activities are found at the Jeju site, followed by the Goseong site of which soils have much different parent rock and textural properties. Though the activities of $^{137}Cs\;and\;^{90}Sr$ on the basis of dry weight are higher in Jeju soils than in Goseong soils, their inventories are similar in both soils due to their textural differences.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.106-116
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• 2021

To secure basic data by monitoring the growth of salmon (Oncorhynchus keta) released to the Taehwa River. After discharge, the characteristics of the young salmon distribution and migration rate habitat were investigated for two years. A total of 4 points [Sunbawi bridge (St.1), Guyeong bridge (St.2), Samho bridge (St.3), and Myeongchon bridge (St.4)] were investigated. The survey of 2017 indicating an increase of 10 mm in average length and 0.8 g in average weight, and the survey of 2018 indicating an increase of 10 mm in average length and 0.5 g in average weight. Among 39 species, 10 insectivorous and 12 omnivorous, are believed to compete with young salmon for food. 6, 5, 6 and 8 predatory fish species has emerged at each site, respectively. According to this study, it is believed that St.1 and St.2 points are more proper as discharge location of young salmon because these two points have less varied in depth, flow rate, salt concentration etc. In addition, it is thought that the night or dawn time in early January is the best discharge time of young salmon fish because predatory fish such as Korean piscivorous chub and bass etc. does not eat food actively at that time.

• Korean Journal of General Education
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• v.4 no.1
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• pp.237-254
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• 2010

For years, poor research and working conditions in the field of science and engineering in Korea led to the migration of gifted students to seek a better academic environment. The primary reason for such a phenomenon is the lack of a coherent education system for gifted students. With the support from the Ministry of Education, Science and Technology and the Korea Foundation for the Advancement of Science & Creativity, Hanyang University launched an exploring project to introduce an Honors Program, aiming to provide specialized and systematic learning opportunities as well as supporting greater academic achievements for gifted students at university-level. Students admitted to this program were selected not by conventional standards but by competency-based selection process, assessed through an in-depth interview. The specific goal of this program is to prepare gifted and talented students not only for an academic pioneer with the highest caliber in the field of science, but also for a global leader equipped with a creative view as well as integrity and a convergent mind. Distinctive features of this program include emphasis on fundamental science and consilience, problem solving skills, first-hand education, interpersonal skills, and global communication skills as well as individualization of the learning experience, among many others. This paper provides a short glimpse of the focus and methodology Honors Program in Hanyang University offers.