• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.347-354
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• 2001

In this study, 3-D FEM analysis are carried out to investigate the effect of the corners and re-entrant corners which can't be analysed by 2-D analysis. The excavation shape is re-entrant type conditions. The wall displacement, earth pressure and effectiveness of the corner struts are investigated in the re-entrant case, The 3D analysis are peformed to evaluate the effect of various factors, such as re-entrant corner size, excavation depth, and presence of struts. The wall displacement and earth pressures are influenced the size of re-entrant corner. Therefore, the effect of re-entrant corner should be considered in the evaluation of the earth pressure and displacement of the corners. Finally, strut-support systems are not effective at the re-entrant corner.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.2
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• pp.33-41
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• 2012

The component cooling water heat exchangers are critical components in a nuclear power plant. As the operation years of the heat exchanger go by, the maintenance costs required for continuous operation also increase. Most heat exchangers have carbon steel shells, tube support plates and flow baffles. The titanium tube is susceptible to flow induced vibration. The damage on carbon steel tube support rod and titanium tube around cooling water entrance area is inevitable. Therefore, analysis of internal flow around the component cooling water entrance and tube channel is a good opportunity to seek for failure prevention practice and maintenance method. The numerical study was carried out by FLUENT code to find out the causes of tube failure and its location.

• Journal of the Korea Society of Computer and Information
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• v.20 no.12
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• pp.107-113
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• 2015

This study analyzed the effect of the factors of introducing information technology(organizational and environmental characteristics) on non-financial performance. As detailed variables of each characteristic, the technical support/task force, users' IT capability, and education/training were used for the organizational characteristics while the degree of competition, external pressure, and uncertainty of environment were used for the environmental characteristics. In the results of the analysis, such factors like technical support/task force, users' IT capability, and education/training of the organizational characteristics had significant influence on non-financial performance. Also, factors such as degree of competition, external pressure, and uncertainty of environment of the environmental characteristics had significant influence on non-financial performance.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.462-465
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• 2016

In the present study, we investigated whether treatment with GBCK25 facilitated the recovery of hemodynamic parameters, left ventricle systolic pressure, left ventricular developed pressure, and electrocardiographic changes. GBCK25 significantly prevented the decrease in hemodynamic parameters and ameliorated the electrocardiographic abnormality. These results indicate that GBCK25 has distinct cardioprotective effects in rat heart.

• Clinical and Experimental Pediatrics
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• v.63 no.1
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• pp.3-7
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• 2020

High-flow nasal cannula (HFNC) is a relatively safe and effective noninvasive ventilation method that was recently accepted as a treatment option for acute respiratory support before endotracheal intubation or invasive ventilation. The action mechanism of HFNC includes a decrease in nasopharyngeal resistance, washout of dead space, reduction in inflow of ambient air, and an increase in airway pressure. In preterm infants, HFNC can be used to prevent reintubation and initial noninvasive respiratory support after birth. In children, flow level adjustments are crucial considering their maximal efficacy and complications. Randomized controlled studies suggest that HFNC can be used in cases of moderate to severe bronchiolitis upon initial low-flow oxygen failure. HFNC can also reduce intubation and mechanical ventilation in children with respiratory failure. Several observational studies have shown that HFNC can be beneficial in acute asthma and other respiratory distress. Multicenter randomized studies are warranted to determine the feasibility and adherence of HFNC and continuous positive airway pressure in pediatric intensive care units. The development of clinical guidelines for HFNC, including flow settings, indications, and contraindications, device management, efficacy identification, and safety issues are needed, particularly in children.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.6 no.2
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• pp.16-19
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• 2010

In this study, the axial ODSCC occurrence of domestic OPR 1000 steam generator tube was caused by the tube weakness and the sludge accumulation in the secondary side of steam generator. Inconel 600 HTMA used as tube material is related to most of tube leakage accidents in the world and also these ODSCCs were detected mainly at the 5th TSP(Tube Support Plate) to the 8th TSP of hot leg side. These elevations(5th TSP to 8th TSP) pave the way for the sludge accumulation. As a result of EC(Eddy Current) Bobbin and RPC data analysis, ODSCCs were occurred at contact points of tube and tube support plate. The more accumulated sludge, the higher occurrence frequency of ODSCC.

• Geomechanics and Engineering
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• v.12 no.2
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• pp.313-326
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• 2017

Based on the reliability theory and limit analysis method, the roof stability of a shallow tunnel is investigated under the condition of surface settlement. Nonlinear Hoek-Brown failure criterion is adopted in the present analysis. With the consideration of surface settlement, the internal energy and external work are calculated. Equating the rate of energy dissipation to the external rate of work, the expression of support pressure is derived. With the help of variational approach, a performance function is proposed to reliability analysis. Improved response surface method is used to calculate the Hasofer-Lind reliability index and the failure probability. In order to assess the validity of the present results, Monte-Carlo simulation is performed to examine the correctness. Sensitivity analysis is used to estimate the influence of different variables on reliability index. Among random variables, the unit weight significantly affects the reliability index. It is found that the greater coefficient of variation of variables lead to the higher failure probability. On the basis of the discussions, the reliability-based design is achieved to calculate the required tunnel support pressure under different situations when the target reliability index is obtained.

• The Journal of Information Systems
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• v.24 no.1
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• pp.169-191
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• 2015

Green supply chain management(GSCM) has emerged as an organizational system which helps organizations and their parter to achieve corporate profit by reducing environmental risk and cost. The main objective of this study is to investigate the relationship among organizational factors(manager support and organizational learning), GSCM practices(investment recovery and eco-design) and GSCM performance based on the BSC. Using a sample of 125 Korean companies, path analysis is used to test the research model. The results shows that the manager support has a positive effect on the investment recovery and eco-design. The results also suggest that the organizational learning directly affect the investment recovery, but do not affect the eco-design. The investment recovery and eco-design have effect on the GSCM performance. In addition, the competitive pressure has moderating effects on most of the relationships between the organizational factors and GSCM practices. This findings provides useful insights for managers seeking to adopt GSCM practices, and also provide useful guidelines for researchers to study GSCM performance.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.96-99
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• 2001

The fatigue life of support bearings is one of the most critical factors for the performance of a control rod driving mechanism. They are operated at high temperature and high pressure and especially lubricated with dramatically low viscosity water. The support bearing is made of standardized 440C stainless steel, and it supports thrust load including the weight of the driving system and external force. Friction and wear characteristics of this material operating under severe lubrication condition is not well known yet, although it is expected to be changed with respect to temperature and boundary pressure. So the friction characteristics are investigated in sliding conditions using the reciprocating tribometer which can simulate the operating conditions. Highly purified water is used as lubricant, and the water is heated up and pressurized. Friction farce on the reciprocating specimens is monitored by the load cells. The results of the experiments are presented in this paper.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.14 no.2
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• pp.16-23
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• 2018

In order to investigate the ways to enhance the seismic performance of APR1400 seismic fragile equipment by direct design changes, four equipment such as Reactor Vessel Support, Integrated Head Assembly, Remote Shutdown Console, and Pressurizer are reviewed using information of the main dimensions, seismic stress evaluation results, design FRS, etc. in this paper. In addition to the direct reinforcement of equipments, the feasibility of seismic isolation for the safety related cabinet is also investigated and the actual adaption plan of a commercial spring-damper system is briefly reviewed.