• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1998.04a
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• pp.101-110
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• 1998

The safe passing maneuver of a large vessel along the designed course through a narrow channel in the flow of strong current is greatly related with her maneuvering characteristics. This paper treats maneuvering characteristic of a large vessel changing her course with the use of her control surface in a narrow channel with strong current. In this paper, the author proposed mathematical models of calculating maneuvering motions of the very large LNG tanker altering course using her control surface and calculated passing tracks of the vessel through the channel and compared the calculated results with those of maneuvering simulations by a desk-top simulator. In general the motions with the calculated values and the simulated motions are well coincided with each other.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.05a
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• pp.141-153
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• 1995

An incremental Total Lagrangian Formulation is implemented for the finite element analysis of laminated composite pressure vessel with consideration of the material and geometric nonlinearities. For large displacements/large rotations due to geometric nonlinearities, the incremental equations are derived using a quadratic approximation for the increment of the reference vectors in terms of the nodal rotation increments. This approach leads to a complete tangent stiffness matrix. For material nonlinearity, the analysis is performed by using the piecewise linear method, taking account of the nonlinear shear stress-strain relation. The results of numerical tests include the large deflection behavior of the selected composite shell problem. When compared with the previous analysis, tile results are in good agreement with them. As a practical example, filament wound pressure vessel is analyzed with consideration of the geometrically and materially nonlinearity. The numerical results agree fairly well with the existing experimental results.

• Journal of the Korean Society of Radiology
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• v.83 no.4
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• pp.918-923
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• 2022

Large vessel vasculitis is characterized by chronic inflammation within the aortic wall and its major branches. The inflammation is considered to occur as a result of immune dysregulation. Hematologic malignancy is one of the rare causes of secondary vasculitis. Herein, we report a rare case of large vessel vasculitis associated with acute myeloid leukemia mimicking primary vasculitis.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.438-442
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• 1996

The design of the vacuum vessel of KT-2(a large-aspect-ratio, mid-size tokamak) is presented. The KT-2 vacuum vessel provides necessary environments to contain a plasma of double-null configuration with elongation of up to 1.8. The vacuum vessel is designed as an all-metal welded structure. Eddy currents are induced on the vessel during all stages of the plasma operation. Influences of the continuous vessel on the plasma were investigated. No significant effect of the vessel on the plasma in every aspect of null formation, plasma initiation, plasma control was found. Stresses and deformations in the vessel by atmospheric pressure and electromagnetic forces due to the eddy currents were calculated using 3D FEM code.

• Journal of the Society of Naval Architects of Korea
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• v.44 no.4
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• pp.379-388
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• 2007

Ever increasing fuel prices and environmental concerns are forcing commercial vessel operators and designers to re-assess current vessel designs with an emphasis on their propulsion systems. The most important parameter determining propulsive efficiency is the diameter of propeller. Many investigations have been carried out to adapt a large and slow turning propeller known as one of the most robust and effective way of achieving high efficiency in ship propulsion system. However, for the same vessel a further increase of propeller diameter would require the modification of the aft end while still paying attention to the hull clearance to prevent excessive propeller excited vibrations. In order to take the advantage of this approach small workboats (e.g. tug boats, fishing vessels etc.) operate in service with a significant increase of aft draught and hence resulting "inclined keel" configuration can be observed. Although it is not unusual to see large vessels sometimes to operate with stern trim to improve their operational performance and fuel efficiency, it is rare to see a such vessel purposely built with an inclined keel feature to fit a large diameter propeller for power saving. This paper investigates the application of the inclined keel configuration to a 3600TEU container vessel with the aim of fitting an 11 % larger diameter propeller (and hence resulting 17.5 % lower rpm) to gain further power saving over the similar size basis container ship with conventional "level keel" configuration.

• The Journal of Fisheries Business Administration
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• v.13 no.1
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• pp.63-84
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• 1982

This study is an analysis of the growing trend from 1971 to 1980 on the four major fisheries in Korea; large powered purse seine, anchovy drag net, two boats large trawl and one boat large trawl. The main purpose of this study is to find some solutions against the problems which these fisheries are faced with, through the analysis of the growing trend of income, capital structure and main ratios of finance. According to the result of the analysis, the problems are as following: \circled1 Revenues per vessel was decreased when catches per vessel was decreased in 1979, 1980. therefore the increase ratio of the revenues per vessel was weakened from 1979. \circled2 Catches per vessel was decreased from 1979 in spite of the increase of gross cathes in its field. \circled3 Production costs in fishing, such as the cost of wages, fuels and repairs, was steadily up year by year. \circled4 Profitability was deteriorated from 1978. \circled5 productivity was lower from 1978. \circled6 Stability was lower from 1978. The solutions out of the above problems are as follows; \circled1 Fisheries resources must be fostered. \circled2 The numbers of vessels should be reduced according to the fisheries resources. \circled3 The precise amount of resources should be dynamically estimated. \circled4 The fishermen must be educated to reduce fishing cost such as the cost of fuels and repairs, etc. \circled5 The old vessels should be replaced. \circled6 The production efficiency should be promoted. \circled7 The rate of interest should be cut down to reduce financial cost.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.3
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• pp.297-305
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• 2023

Objective: The term "weekend effect" refers to an increase in the mortality rate for hospitalizations occurring on weekends versus weekdays. In this study, we investigated whether such an effect exists in patients undergoing mechanical thrombectomy for acute ischemic stroke with large vessel occlusion (currently the standard treatment for this condition) at a single center in Japan. Methods: We surveyed 151 patients who underwent mechanical thrombectomy for acute ischemic stroke with large vessel occlusion (75 and 76 patients were treated during daytime and nighttime, respectively) from January 2019 to June 2021. The items evaluated in this analysis were the rate of modified Rankin Scale ≤2 or prestroke scale, mortality, and procedural treatment time. Results: The rates of modified Rankin Scale ≤2 or prestroke scale and mortality at 90 days after treatment did not differ significantly between daytime and nighttime (41.3% vs. 29.0%, p=0.11; 14.7% vs. 11.8%, p=0.61, respectively). The door-to-groin time tended to be shorter during daytime versus nighttime (57 [IQR: 42.5-70] min vs. 70 [IQR: 55-82]) min, p=0.0507). Conclusions: This study did not reveal differences in treatment outcome between daytime and nighttime in patients undergoing mechanical thrombectomy for acute ischemic stroke with large vessel occlusion. Therefore, the "weekend effect" was not observed in our institution.

• Nuclear Engineering and Technology
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• v.47 no.1
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• pp.66-73
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• 2015

Background: A numerical simulation was carried out to investigate the difference between internal and external heat-flux distributions at the reactor vessel wall under in-vessel retention through external reactor vessel cooling (IVR-ERVC). Methods: Total loss of feed water, station blackout, and large break loss of coolant accidents were selected as the severe accident scenarios, and a transient analysis using the element-birth-and-death technique was conducted to reflect the vessel erosion (vessel wall thickness change) effect. Results: It was found that the maximum heat flux at the focusing region was decreased at least 10% when considering the two-dimensional heat conduction at the reactor vessel wall. Conclusion: The results show that a higher thermal margin for the IVR-ERVC strategy can be achieved in the focusing region. In addition, sensitivity studies revealed that the heat flux and reactor vessel thickness are dominantly affected by the molten corium pool formation according to the accident scenario.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.147-155
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• 1999

In this study, the stability analysis of a fishing vessel in a seaway was done. The stability analysis is an important item in the ship design, and so the ship registers of each nation constrain the ships to be followed the stability criterion. Stability variation, exciting forces due to wave and wind, and the broaching phenomena cause the capsizing of a ship. In this study, the stability analysis to study of the capsizing of a fishing vessel was performed. The relation between the speed of the ship and the wave length, that makes the encountering frequency vanish, was obtained. It was found that the encountering frequency tend to be zero when the wave whose length and direction are similar to those of ship. In this case, the possibility of dangerous situation becomes high. The calculated restoring arm becomes small when the ship is located near the wave crest. In general, the selected small fishing vessel is better than the large ship with respect to the stability, however the wave height becomes relatively high because of her small length Kim(l994) calculated the stability variation of the large cargo ship, the results of which showed the changes in stability great. But in the selected small fishing vessel in this study, the changes was small in comparison with the larger ship. This reason seems to be the shape of her midship section. In large cargo ships, the block coefficient is large, but that of the fishing vessel is relatively small and the small fishing vessel has chine, therefore the center of buoyancy moves much when the ship is inclined. It is desirable that the dynamic stability analysis for a fishing vessel, whose speed and direction are similar to those of waves, shall be done in the near future.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.12 no.1
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• pp.115-125
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• 2016

The prototype SFR has currently been under design by KAERI. The size of its major components is much larger than that of APR1400 and high temperature materials are applied for it. The increased size of components and those specific materials effect on material procurement, manufacturing process and fabrication facilities. The manufacturing methods are studied for Reactor Vessel/Guard Vessel, Control Rod Drive Mechanism, Heat Exchanger, Primary Pump, Reactor Vessel Internals, Steam Generator and In-Vessel Transfer Machine. The proper manufacturing methods are suggested for each component including side forging technology for ultra large forgings of Reactor Vessel to minimize the weld seams on which In-service Inspection should be conducted.