• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.7 no.2
• /
• pp.42-47
• /
• 2011

The purpose of this study is to investigate the effects of through thickness on the mechanical properties and microstructural features in Mod. 9Cr-1Mo steels for RPVs. The microstructures at all locations were typically tempered martensite, but small amount of delta ferrite was observed at the center region. The prior austenite grain size increased with the depth from the surface. The yield strengths of center and 1/4T location were higher than that of surface by 30MPa. The impact toughness of center was low compared to those of other specimens. Also, upper shelf energy was low at the center. The toughness deterioration in center might be caused by larger size of the prior austenite grains and existence of the delta ferrite.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.5
• /
• pp.60-67
• /
• 2003

For risk or reliability assessment of ship structures against particular hazardous situations such as total loss or sinking due to hull girder collapse, the short-term based response analysis rather than the long-term response analysis is required to determine wave-induced bending moments when the ship encounters a storm of specific duration and with a specified small encounter probability. In the present study, the effects of operational condition and sea states on wave-induced bending moments of large merchant vessels are investigated. A series of the short-term response analyses for a hypothetical VLCC and a Capesize bulk carrier (CSBC) are carried out with varying operational condition and sea states which include ship speed, significant wave height and wave persistence time, using the linear-strip theory based program ABS/SHIPMOTION and the MIT sea-keeping tables. The computed results are also compared with the IACS design formula predictions. The results and insights developed from the present study are summarized.

• Progress in Medical Physics
• /
• v.5 no.1
• /
• pp.25-39
• /
• 1994

To measure the velocity of heart wall and local flow transctaneously in blood vessels, we have developed a single channel 3.1 MHz pulsed ultrasonic Doppler velocity meter. Ultrasound pluse width and repetition frequency (PRF) used in the velocity meter is 1 ${\mu}$sec 6kHz reapectively, and the Doppler shift of the backscattered echo signal is sensed in a phase detector by coherent demodulation method. From the output of the phase detector, the Doppler signal corresponding to the mean velocity of acoustic wave scatterers over a small region is obtained by using a range gate, sample holder and band-pass filter. Mean frequency of Doppler signal is estimated by zero-crossing counter and the instantaneous velocity of scatters is displayed as a function of time. It is possible to estimate velocity profile, volume flow and flow acceleration of vessels in man if the number of channels and range resolution in increased.

• Journal of the Korean Society of Safety
• /
• v.21 no.3 s.75
• /
• pp.38-44
• /
• 2006

The majority of both small and large-scale experiments on gas explosion have been carried out in the explosion instruments with cylindrical tubes of a high length/diameter ratio and vessels of a high height/length ratio, focusing on investigating the interaction between propagating flame and obstacles inside the tubes or vessels. The results revealed that there is a strong interaction between the propagating flame and turbulence formed after the flame passes the obstacle. However this paper focuses on analyzing the pressure impact or profile outside the vent in vented gas explosion in a partially confined chamber by performing gas explosion experiments in a reduced-scale experimental assembly properly constructed. This study has considered eight different cases in gas explosion based on variation of three kinds of parameters such as height of vessel, shape of the vent and vent size, and reveals that the large vessel with big size circle vent is more danger to the target than others because the overpressure is spread out faraway horizontally and vertically.

• The Korean Journal of Cytopathology
• /
• v.17 no.2
• /
• pp.153-158
• /
• 2006

Low-grade fibromyxoid sarcoma (LGFMS) is a rare soft tissue tumor. There have been only a few prior fine-needle aspiration (FNA) cytological reports. Recognition of this tumor is important because of its potential for metastasis despite its indolent nature and its deceptively bland cytologic appearance. A 60-year-old male presented with a slowly growing mass in the left calf detected 10 years ago. The patient underwent surgical excision. FNA cytology was performed directly on the mass. The smears showed low cellularity composed of hypercellular tissue fragments, hypocellular loose aggregates, and stripped nuclei. The cytoplasm was seen as either collagenous material or very thin fibrillary collagen strands. Tumor cells had spindle, ovoid, or irregular nuclei, fine chromatin, and small nucleoli. Focally slight degree of nuclear pleomorphism is noted. There were no mitotic figures. Blood vessels were frequently seen. Immunocytochemically, tumor cells were negative for S-100 protein, desmin, smooth muscle actin, and CD34. The diagnosis of LGFMS is rarely possible by cytology alone; however, LGFMS should be included in the differential diagnosis of spindle-cell tumors consisting of hypercellular and hypocellular components with some capillary-sized vessels arising in the deep soft tissue of the lower extremities, particularly the thigh. The immunocytochemical findings are of help in the differential diagnosis.

• Transactions of the Korean Society of Pressure Vessels and Piping
• /
• v.12 no.1
• /
• pp.49-55
• /
• 2016

This paper analyzed a root cause of abnormality in the temperature and vibration at generator-side bearing of motor generator set (MG Set), which is a power supply system to control element drive mechanism (CEDM) of nuclear power plants (NPPs), and modified the design of roller-type and sealing method to improve the abnormalities. From the inspection of MG Set and analysis of temperature variation during service, it was found that the abnormal temperature transition was basically associated with original design of generator-side bearing, whose roller was axially restrained by inner race, and that the abnormal vibration level was caused by inserting small chips of cage and V-ring, which were generated due to the abnormal temperature transition at roller bearing. Type of bearing and sealing method were modified based on these analyses. The temperature and vibration level measured at roller bearing showed that the modifications clearly improved the operational stability of MG Set.

• Journal of the military operations research society of Korea
• /
• v.36 no.2
• /
• pp.125-141
• /
• 2010

This research is to review various theories on leadership and to apply the transformational leadership that is suitable for military organization to captains of small naval vessels. The research comprehends types and adaptability of the leadership of captains, analyzes problems of them, and suggests the more desirable ways to develop leadership. In order to achieve these objects of the research, positive analyses were conducted through research on various documentations and survey. The first procedure was to survey the status of leadership on mine sweeper prior to the education on transformational leadership. The second procedure is to survey the result of the education on transformational leadership. Also, in order to understand the difference among the controlling groups, random vessels were selected for surveying the effectiveness of the application of transformational leadership on the same period of time.

• The Journal of Fisheries Business Administration
• /
• v.28 no.1
• /
• pp.1-26
• /
• 1997

The Proposal of this paper is to draw up solution about fishing disputes in Korea coastal waters. Small fishing vessels under 8 metric tons which is regulated by the provincial governors, must operate within provincial boundary on the sea as in fishery policy of Korea. on this, I think that the present situations of fishing disputes have related to the fishing license system. Problem of this kind, Before 1970's, fishing disputes rarely took place, and it, if any, did not bring any social conflicts or disputes. Since 1980's, some of fishing disputes have been reported within fisheries society Recently, The disputes have been increasing to become social conflicts between local people concerned and have evoked an argument on whether the provincial boundary on the sea exists. If such disputes continues to increases or remains unsolved, they will bring a tremendous social cost such as an accelerated decrease in fish resources, degradation of fishing grounds, disorder in fishing, destruction of fisheries culture and so on. The reasons for the growing disputes can be specified as fellows : the degradation of fish resources, the present fishing license system which inherently causes competitions in fish catching, irrational ceiling system of fishing vessels, legal problem on existing boundary between neighbouring two provinces, the functional problem of national or regional fishery coordination committee which has been established to coordinate general fishing disputes. This study has also dealt with Japan's experiences in fishing disputes which has the history of more than a hundred years and its coordinating mechanism. In the discussion section, some possible solutions have been briefly touched fer further study.

• Nuclear Engineering and Technology
• /
• v.48 no.3
• /
• pp.805-819
• /
• 2016

The numerical simulation methodologies to evaluate the structural behaviors of prestressed concrete containment vessels (PCCVs) have been substantially developed in recent decades. However, there remain several issues to be investigated more closely to narrow the gap between test results and numerical simulations. As one of those issues, the effects of no stiffness inside unbonded tendon ducts on the behavior of PCCVs are investigated in this study. Duct holes for prestressing cables' passing are provided inside the containment wall and dome in one to three directions for general PCCVs. The specific stress distribution along the periphery of the prestressing duct hole and the loss of stiffness inside the hole, especially in an unbonded tendon system, are usually neglected in the analysis of PCCVs with the assumption that the duct hole is filled with concrete. However, duct holes are not small enough to be neglected. In this study, the effects of no stiffness inside the unbonded tendon system on the behaviors of PCCVs are evaluated using both analytical and numerical approaches. From the results, the effects of no stiffness in unbonded tendons need to be considered in numerical simulations for PCCVs, especially under internal pressure loading.

• Archives of Plastic Surgery
• /
• v.33 no.2
• /
• pp.187-192
• /
• 2006

The perforator flaps are based on cutaneous vessels which are originated from a main pedicle and penetrate fascia or muscle to reach the skin. The lateral lower leg is one of the most suitable areas for harvesting perforator flaps because a number of perforator vessels exist. The authors applied peroneal perforator flaps in nine patients. Five flaps were reverse island flaps based on peroneal artery and septocutaneous perforator, and four flaps were free flap based on musculocutaneous perforator only. The recipient site was the posterior ankle in three patients, posterior heel in three patients, lateral malleolus, anterolateral ankle, and foot dorsum in one patient each. The flap size ranged from 5 to 12cm long, from 3 to 5cm wide, and the primary closure of the donor site was possible in most cases. All flaps, except for the flap in two patients in the reverse island flap series, survived completely. The peroneal perforator flap is a very thin, pliable flap with minimal donor site morbidity and is suitable for the reconstruction of small and medium sized superficial skin defects. Also, this flap may be considered as an alternative to radial forearm flap or other perforator flaps.