• Economic and Environmental Geology
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• v.50 no.6
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• pp.477-486
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• 2017

In this study, we analyze precise seabed geomorphology and conditions for comparing the nearshore areas of the Dongdo(East Island) and the Seodo(West Island) using detailed bathymetry data and seafloor backscattering images, in Dokdo, the East Sea. We have been obtained the detailed bathymetry data and the seafloor backscattering data. The survey range is about $250m{\times}250m$ including land of islets to the nearshore areas of the southern part of the Dongdo and the Seodo. As a result of bathymetry survey, the southern area of the Dongdo(~50 m) is deeper than the Seodo(~30 m) in the water depth. The survey areas are consist of extended bedrocks from land of the Dongdo and the Seodo. The underwater rock region of the Seodo is larger than the Dongdo. In spite of similar extended rocks features from islets, there are some distinctive seabed characteristics between the southern nearshore areas of the Dongdo and the Seodo. The Talus-shaped seafloor environment formed by gravel and underwater rocks originating from the land of the Dongdo is up to about 15 m depth. And the boundary line of between extended bedrocks and seabottom is unclear in the southern nearshore of the Dongdo. On the other hand, the southern coast of the Seodo is characterized by relatively large scale underwater rocks and evenly distributed sediments, which clearly distinguish the boundary of between extended bedrocks and seafloor. This is because the tuff layers exposed to the coastal cliffs of the Dongdo are weak against weathering and erosion. It is considered that there are more influences of the clastic sediments carried from the land of the Dongdo compared with the Seodo. Particularly, the land of the Dongdo has been undergoing construction activities. And also a highly unstable ground such as faults, joints and cracks appears in the Dongdo. In previous study, there are dissimilar features of the massive tuff breccia formations of the Dongdo and the Seodo. These conditions are thought to have influenced the different seabed characteristics in the southern nearshore areas of the Dongdo and the Seodo.

• Journal of Biosystems Engineering
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• v.1 no.1
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• pp.1-6
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• 1976

This paper is the third one of the study on balanced type oscillating mole-drainer, the first one was presented in No 9. Gyeongsang College Report and the second one in Vol. 17, No.4 of the KSAE. In the first part of this study, the characteristics of traction forces between the nonoscillating earth working equipments and oscillating ones was compared. A model of the balanced type oscillating mole-drainer, which composed of a mechanism that may reduce the machine vibration, was designed following the dimensional analysis and similitude technique. The model test was carried out to clarify the balancing mechanism of the oscillating parts and other parts of the machine. In the light of the results from the model tests, a prototype machine was made for experimental purpose. Results from the field test by a reported in the near future. In the second report, the model tests were carried out under the same soil conditions, i.e, . oscillating frequency, running velocity, and oscillating amplitude, etc. It was clear that use of balanced type oscillating model could substantially reduce the vibration of the whole system of the machine, when compared with the nonoscillating type model. In this paper(the third report), results of investigation on the traction force, power requirement, and moment. etc, is presented. Analysis of variance technique was used for analyzing the effect of the frequency, amplitude, and running velocity on the draft force, torque, power requirements, and moments. The results obtained from the model tests are as follows, 1) By practicing a balanced-type oscillating mole-drainer, it was possible to reduce the traction resistance by 55.1-61. 2 percent of traction resistance, however, was 1.75 - 1.95 times greater than the value of resistance which was induced by use of a mole-drainer with single bullet. The resistance of rear shank against soil was considered as a main causing factor of the above results. 2) As the oscillation frequency was increased, the traction resistance was decreased. Considering on the effect of oscillation the greater the amplitude, and the slower the running velocity was, the greater the reduction ratio of traction resistance was. 3) The ratio of the traction resistance of oscillating mole-drainer to that of non-oscillating one could be represented as a function of dimensionless variable (V/$Af$). The results from the tests were well agreed with the reported results from the experim ents on oscillation plow or hoe. 4) By taking a lower value of (V/$Af$), reducing the traction resistance was possible. This fact meant, however, that the efficiency of mole drain practice would be lower. 5) It was experimentally confirmed under the same condition of soil that the variable (R/$rD1^3$) could be represented as a function of a variable($V^2/gD$) when a non\ulcornerocillating mole-drainer was used. 6) When a oscillating mole-drainer was used, the variable(R/$rD_1^{3}$) could be represented as a function of two variables ($v^2/gD_1$) and (V^2/gD_1$). 7) The torque was not affected by a change of frequency. However, a relation of proportionality existed between torque and amplitude, running velocity, and ratio of bullet diameter. When a balanced type oscillating mole-drainer with two bullets was used, torque was increased by 52.8-78. 4 percent and total power requirement was also increased. 8) Total power requirement was increased linearly in accordance with the increasing frequency, 41.96 percent of total power was used for oscillating action. The magnitude of total power requirement was 1. 8-9. 4 times greater than that of a non-oscillating mechanism. In the view point of power requirement, it was not advisable to increase the frequency, amplitude, running velocity, and ratio of bullet diameter at the same time. 9) Only the positive moment occured in the rear shank. Change of the diameter of a rear bullet, could not affect the balancing against the soil resistance. It was necessary for rear bullet to have a large resistance against soil only when the rear bullet was in backward motion. 10) Within an extent of the experimental base, optimum limits for several design factors were A=0.5cm, $f$=22.5Hz, V=O. 05m/sec, and $\lambda$=1.0 By adapting these values traction resistance was reduced by 40 percent and vibration acceleration wa s reduced by 60 percent. Even though the total , power requirements for operating a balanced type oscillation mechanism was greater ~than that of non-oscillating one, using a oscillating mechanism would be more effective. Because a balanced type oscillating mechanism is used, tractive resistance will be reduced and then the lighter . tractive equipment could be used.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.138-147
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• 2007

An emergy concept was used to evaluate the environment and economy of the Han River basin in Korea and to suggest policy perspectives far the sustainable utilization of its environment and associated estuarine ecosystem. The economy of the basin used $5.19{\times}10^{23}\;sej/yr$ of emergy in 2005. The economy of the Han River basin was heavily dependent on outside energy sources from foreign countries and other parts of Korea, with internal sources, renewable and nonrenewable, contributing only 15.6% to the total emergy use. The basin's trade balance in terms of emergy showed trade surplus, whereas there was a deficit in monetary terms. The population of the Han River basin was far greater than the carrying capacity calculated using the emergy flow, with renewable carrying capacity only at 1.8% of the basin's population and developed carrying capacity at 14.3%. The economy of the basin imposed a substantial stress on its environment, with an environmental loading ratio of 54.8. Overall, the economy of the Han River basin was not sustainable with an emergy sustainability of 0.02. These are reflected in lower quality of living expressed in the emergy term than the national average. Deconcentration of population and economic activities is needed to reduce environmental stress on the environment of the basin and its valuable estuarine ecosystem. Policies to restore ecosystem productivity of the basin are also needed to ensure the sustainability of the basin's economic activities and the sustainable utilization of the Han River estuary. In this regard, it is urgently needed for the Korean government to implement sustainable management measures for the Han River estuary, a well-preserved, productive natural estuarine ecosystem in Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.5
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• pp.455-461
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• 2002

limiting nutrients for phytoplankton were determined by dissored inorganic nitrogen/phosphorous (DIN/DIP) in situ and algal bioassay experiment in the Seomjin River estuary during a study period from March 1999 to October 2001. DIN/DIP ranged from 14.7 to 681.1 during the study period. DIN/DIP was over 16 at the upper and middle estuarine region where salinity was lower than 25 psu and chlorophyll a concentration was high, probably indicating P-limitation in this region while the ratio was less than 16 at the high saline (> 25 psu) region, reflecting the supply of DIP from Gwangyang Bay and thereby indicating N-limitation at the lower estuarine region. These results suggested that the spatial distribution of DIN/DIP in the study region was controlled by the high supply of phosphate from Gwangyang Bay, the low input from Seomjin River and the active uptake by phytoplankton within the estuarine system. The bioassay experiments using Skeletonema costatum, Thalaasiosira rotula and in situ phytoplankton assemblage displayed relatively higher growth of phytoplankton in the P-added culture media, indicating P-limitation. This result was well consistent with the spatial distribution of inorganic nutrients. S. costatum showed a rapid adaptation to the low salinity compared to other phytoplankton species. This phenomenon seemed to account for the strong (> $90\%$ in total cell number) S. costatum bloom in autumn in this estuary. Moreover, although phytoplankton growth rate was higher in the P-added culture media at the end of culture experiment of in situ phytoplankton, the fast growth in the trace metal-added media at the beginning of the experiment suggested a possibility of limitation by other micro-nutrients such as trace metal and vitamin etc.

• Radiation Oncology Journal
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• v.22 no.2
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• pp.124-129
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• 2004

Purpose : To evaluate the clinical findings, prognosis and treatment strategy of patients with neuroendocrine carcinoma of cervix. Materials and Methods: Thirteen patients with neuroendocrine carcinoma of cervix were included in this study, as confirmed histologically and immunohistochemically at the Dongsan Medical Center, Keimyung University, between May 1944 and October 2001. The mean age of patients was 56 years with a range of 32 to 78 years of age. According to the FIGO staging system, there were 5 patients with stage IB carcinoma, 5 patients with IIA, and 3 patients with stage IIB. Four patients underwent radical hysterectomy with pelvic lymphadenectomy, 3 of these patients also received postoperative radiotherapy, and one patient underwent extrafascial hysterectomy after radiotherapy. Primary radiotherapy was done in 9 patients, and 3 were irradiated postoperatively. Nine patients received chemotherapy, 7 received neoadjuvant and 2 received concurrent chemoradiotherapy. The radical purpose of radiotherapy consisted of external irradiation to the whole pelvis (4,500 $\~$5,400 cGy) and intracavitary irradiation (3,000 $\~$ 3,500 cGy). Results : The mean follow up duration was 36 months with a range of 3 to 104 months. The overall 5-year survival rate was 61.5$\%$ and the 5-year survival rates for stage IB, IIA, IIB were 60.0$\%$, 60.0$\%$, and 66.7$\%$ respectively (p=0.99). Eight patients are still alive without disease, and all of the 5 patients with recurrence are dead due to distant metastasis. Conclusion : Neuroendocrine carcinoma of cervix is highly aggressive, with early lymphatic dissemination and a high rate of distant recurrence. Therefore, an aggressive therapeutic strategy Is required to obtain pelvic and distant disease control. Multimodal therapy should be considered at the time of Initial diagnosis.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.662-671
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• 2015

As the type of Hazardous and Noxious Substances(HNS) becomes various and the transport volume of HNS increases, HNS spill incidents occur frequently on land and the sea. In view of various damages to human lives and properties by HNS spills, it is necessary to educate and train professional personnel in preparation for and response to potential HNS spills. This study shows the current state of response systems and education courses against HNS spill incidents on land and the sea to compare those with each other between land and sea in Korea. Incident command system on land are basically similar to that at sea, but leading authority which is responsible for combating HNS spills at sea is changeable depending on the location of HNS spill, as it were, Korea Coast Guard(KCG) is responsible for urgent response to HNS spill at sea, while municipalities are responsible for the response to HNS drifted ashore. Education courses for HNS responders on land are established at National Fire Service Academy(NFSA), National Institute of Chemical Safety(NICS), etc., and are diverse. Education and training courses for HNS responder at sea are established at Korea Coast Guard Academy(KCGA) and Marine Environment Research & Training Institute(MERTI), and are comparatively simple. Education courses for dangerous cargo handlers who work in port where land is linked to the sea are established at Korea Maritime Dangerous Goods Inspection & Research Institute(KOMDI), Korea Port Training Institute(KPTI) and Korea Institute of Maritime and Fisheries Technology(KIMFT). Through the comparison of education courses for HNS responders between land and sea, some recommendations such as extension of education targets, division of an existing integrated HNS course into two courses composed of operational level and manager level with respective refresh course, on-line cyber course and joint inter-educational institute course in cooperation with other relevant institutes are proposed for the improvement in education courses of KCG and KOEM(Korea Marine Environment Management Corporation) to educate and train professionals for combating HNS spills at sea in Korea.

• Journal of the Korean Chemical Society
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• v.47 no.6
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• pp.614-618
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• 2003

$Sr_2Ru_{1-x}Cu_xO_{4-y}(0.0{\le}x{\le}0.5)$ compounds were prepared using a conventional solid state reaction. Based on the Rietveld refinements of X-ray diffraction results, it is revealed that $Sr_2Ru_{1-x}Cu_xO_{4-y}$ compounds are the single phases with K2NiF4 type tetragonal system in the range of 0=x=0.3, while the mixed phases of$Sr_2RuO_4$ and $Sr_2CuO_3$ in the range of $0.4{\le}x{\le}0.5$. By means of X-ray photoelectron spectroscopy, the valence states of Ru and Cu in $Sr_2Ru_{1-x}Cu_xO_{4-y}$, have been confirmed to 4+ and 2+, respectively. The bond length difference between $Ru-O_1 ({\times}4)\;and\;Ru-O_2 ({\times}2)\;in\;RuO_6$ octahedron is gradually decreased with increasing Cu content in $Sr_2Ru_{1-x}Cu_xO_{4-y}$, which results in the lower c/a ratio. So, it might be assured that the variation of local symmetry of $RuO_6$ octahedron is very closely related to the transporting property of $Sr_2Ru_{1-x}Cu_xO_{4-y}$ compounds. The behavior of resistivity discloses that the metallic property in $Sr_2RuO_4$ changes into the semiconducting one in proportion to the Cu content in $Sr_2Ru_{1-x}Cu_xO_{4-y}$.

• Nuclear Engineering and Technology
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• v.39 no.5
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• pp.603-616
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• 2007

Roy Huddle, having invented the coated particle in Harwell 1957, stated in the early 1970s that we know now everything about particles and coatings and should be going over to deal with other problems. This was on the occasion of the Dragon fuel performance information meeting London 1973: How wrong a genius be! It took until 1978 that really good particles were made in Germany, then during the Japanese HTTR production in the 1990s and finally the Chinese 2000-2001 campaign for HTR-10. Here, we present a review of history and present status. Today, good fuel is measured by different standards from the seventies: where $9*10^{-4}$ initial free heavy metal fraction was typical for early AVR carbide fuel and $3*10^{-4}$ initial free heavy metal fraction was acceptable for oxide fuel in THTR, we insist on values more than an order of magnitude below this value today. Half a percent of particle failure at the end-of-irradiation, another ancient standard, is not even acceptable today, even for the most severe accidents. While legislation and licensing has not changed, one of the reasons we insist on these improvements is the preference for passive systems rather than active controls of earlier times. After renewed HTGR interest, we are reporting about the start of new or reactivated coated particle work in several parts of the world, considering the aspects of designs/ traditional and new materials, manufacturing technologies/ quality control quality assurance, irradiation and accident performance, modeling and performance predictions, and fuel cycle aspects and spent fuel treatment. In very general terms, the coated particle should be strong, reliable, retentive, and affordable. These properties have to be quantified and will be eventually optimized for a specific application system. Results obtained so far indicate that the same particle can be used for steam cycle applications with $700-750^{\circ}C$ helium coolant gas exit, for gas turbine applications at $850-900^{\circ}C$ and for process heat/hydrogen generation applications with $950^{\circ}C$ outlet temperatures. There is a clear set of standards for modem high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a $500{\mu}m$ diameter $UO_2$ kernel of 10% enrichment is surrounded by a $100{\mu}m$ thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of $35{\mu}m$ thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum $1600^{\circ}C$ afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modem coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond $1600^{\circ}C$ for a short period of time. This work should proceed at both national and international level.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.765-773
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• 2000

The degradation of humic acid using $TiO_2$ coatings was studied, $TiO_2$ coatings were prepared by dip-coating method. Sol solutions for coating were prepared by mixing the gel, which can be produced by the reaction of $TiOCl_2$ and $NH_4OH$ solution, and hydrogen peroxide solution, and hydrolysis of titanium tetraisopropoxide (TTIP). It was shown from XRD that coatings from sol aged at $100^{\circ}C$ for 18h with titanium peroxo solution were crystallized to anatase in the range of temperatures of $25^{\circ}C$ to $500^{\circ}C$. In contrast, those coated from TTIP were crystallized to anatase at temperature above $400^{\circ}C$. So the sols originated from $TiCl_4$ can be applied for not only on the heat-resistance substrates but on the plastic substrates. Thickness and the quality of the films were dependent on the withdrawing speed, the concentration of sol, and the number of coating. The films showed various interference colors depending on the thickness of them. In the case that the films coated 2 times at withdrawing speed of 2.5cm per minute by 0.2M sol, the films had a transparent light blue color with thickness of around 50nm. It was known from the result of photo-degradation by $TiO_2$ coatings using humic acid that the removal efficiency of $COD_{cr}$ was over 85% after illumination of $UV/H_2O_2$ for 40min. and that of UV/VIS absorbable materials was over 95%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.4
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• pp.395-407
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• 2002

A 3D hydrodynamic-ecological coupled model was applied to estimate a food supply to oysters in Geoje-Hansan Bay where is one of the oyster culturing sites in Korea, In this study, the primary productivity (PP) was adopted as an index of food supply, and the spatial patterns of average chlorophyll a concentration during a culturing seasons from September to May of the following year were simulated by the model, The numerical result showed that PP was high in the inner part of the bay and the adjacent areas of Hwado island, but low in the outer. This result indicates that PP is essentially influenced by anthropogenic nutrient loadings in the system. The model was calibrated using the field data in May which is non culturing season of oysters and a simulated phytoplankton biomass agreed fairly well with the observed data ($R^{2}=0.70$, $RE=10.3\%$). The computed food supply varied from 0.19 to $1.27\;gC/m^{2}/day$ with a mean value of $0.62 gC/m^{2}/day$ from September to May. The highest value was showed in May ($1.27 gC/m^{2}/day$) and the lowest was in February ($0.19 gC/m^{2}/day$).