• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.351-356
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• 1997

In the des19n of KNGR (Korea Next Generation Reactor), we believe that economy is one of the most important factors to be considered Thus, we reviewed and evaluated the consequences of designing the head area into an integrated package from an economical point of view. The refueling outage durations of the nuclear power plants currently in operation In Korea, some having and others not having integrated head package, are compared. This paper discusses the characteristics of head area design and the critical design issues of KNGR head area to evaluate the effect of the head area characteristics on the outage duration.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.922-927
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• 1998

Pipe cooling has been popularly used in the mass concreting work to reduce temperature of the structure since it is known to be the easiest way to apply and has been the customary usage. But wrong application of the system results in the harmful effect on the structure by crack formation due to thermal shocks and improper cooling schemes. Thus, this study aims at the suppling of effective cooling methods through parametric study. For this, circulating method, velocity of water supply and circulating duration were selected as critical factors affecting the effectiveness of cooling system. As a results of thermal analysis, it was found that too much thermal gradient in the vicinity of the pipe creates localized radial or circumferential cracks. The duration of circulating cooling may be recommended to be as short as several days which may safely reduce the concrete temperature to below a final stable value. It was also found that pipe cooling is more effective to decrease the degree external restraints than internal one.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.166-173
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• 2002

Seismic bridge failure due to the combined effects of earthquake and local scour are examined in probabilistic perspectives. The seismic responses of multi-span continuous bridge with deep foundations are evaluated with a simplified mechanical model. The probabilistic local scour depths around the deep foundations are estimated by using the Monte Carlo simulation. From the simulation results, it is found that seismic responses of a bridge slightly increase due to the local scour effect. The effect of local scour on the global motion of the continuous bridge is found to be significant under weak seismic intensity. In addition, the duration to regain its original foundation stiffness is critical in estimating the probability of foundation failure under earthquake. Therefore, the duration in recovering the foundation stiffness should be determined reasonably and the safely of the whole bridge system should be evaluated by considering the scour effect.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.6
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• pp.72-79
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• 1998

The goals of this research are to understand the regeneration characteristics in diesel particulate filter(DPF) using the cerium additive and throttling. The effects of throttling duration and spring tension of throttling valve were studied. Measurements were made on a 6 cylinder direct injection diesel engine and included pressure drop, filter inlet temperature, oxygen concentrations, and torque. The major conclusions of this work include; (i) the pressure drop is increased with increase of the engine load and the engine speed; (ii) the inlet temperature of the filter is reached $350^{\circ}C$ with certain engine operating condition which leads to sufficient temperature to regenerate with additive; and (iii) oxygen concentrations in the filter and engine torque during throttling operation are decreased by 2 percent and 36 percent, respectively, which are not critical about regeneration and vehicle operation.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.143-149
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• 2010

The river master plan was established every 10 years in Korea. The basin characteristics of 62 small and medium size rivers of which master plans were recently established during the past three years in Gyeonggi-do were investigated, and design rainfalls and design floods in the past and the latest were compared and analyzed. It was predicted that basin data and flood estimating method changed design flood. The quantitative amount of design floods were analyzed for 6 basins like Gungunchen etc. As the results, the increasing factors of design flood were the application of critical duration time, temporal time of rainfall and the increase of CN value. The decreasing factors of design flood were the application of Huff's rainfall distribution instead of Mononobe one and the ARF. The application of critical duration time increased flood about 60% whereas the application of Huff's rainfall distribution method estimated less flood than Mononobe about 62%. Considering critical duration time and changing rainfall distribution were the most important factors of increasing or decreasing design flood. However, trends of flood variation were differently analyzed by factors in 6 basins because characteristics of topography, weather, hydrology and hydraulic were different, now that correlations were not found between factors and flood variation. Flood variation is evaluated by complex effects of factors so new flood recalculated by reasonable methods should be considered as design flood.

• Tuberculosis and Respiratory Diseases
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• v.82 no.4
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• pp.348-356
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• 2019

Background: Recently, the number of lung transplants in South Korea has increased. However, the long-term outcome data is limited. In this study, we aimed to investigate the long-term outcomes of adult lung transplantation recipients. Methods: Among the patients that underwent lung transplantation at a tertiary referral center in South Korea between 2008 and 2017, adults patient who underwent deceased-donor lung transplantation with available follow-up data were enrolled. Their medical records were retrospectively reviewed. Results: Through eligibility screening, we identified 60 adult patients that underwent lung (n=51) or heart-lung transplantation (n=9) during the observation period. Idiopathic pulmonary fibrosis (46.7%, 28/60) was the most frequent cause of lung transplantation. For all the 60 patients, the median follow-up duration for post-transplantation was 2.6 years (range, 0.01-7.6). During the post-transplantation follow-up period, 19 patients (31.7%) died at a median duration of 194 days. The survival rates were 75.5%, 67.6%, and 61.8% at 1 year, 3 years, and 5 years, respectively. Out of the 60 patients, 8 (13.3%) were diagnosed with chronic lung allograft dysfunction (CLAD), after a mean duration of $3.3{\pm}2.8years$ post-transplantation. The CLAD development rate was 0%, 17.7%, and 25.8% at 1 year, 3 years, and 5 years, respectively. The most common newly developed post-transplantation comorbidity was the chronic kidney disease (CKD; 54.0%), followed by diabetes mellitus (25.9%). Conclusion: Among the adult lung transplantation recipients at a South Korea tertiary referral center, the long-term survival rates were favorable. The proportion of patients who developed CLAD was not substantial. CKD was the most common post-transplantation comorbidity.

• Tuberculosis and Respiratory Diseases
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• v.82 no.4
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• pp.335-340
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• 2019

Background: Snoring is the cardinal symptom of obstructive sleep apnea (OSA). Snoring and upper airway obstruction associated with major oxygen desaturation may occur in populations undergoing flexible bronchoscopy. Methods: To evaluate the prevalence of patients at a high risk of having OSA among patients undergoing bronchoscopy with sedation and to investigate whether snoring during the procedure predicts patients who are at risk of OSA, we prospectively enrolled 517 consecutive patients who underwent the procedure with moderate sedation. Patients exhibiting audible snoring for any duration during the procedure were considered snorers. The STOP-Bang (Snoring, Tiredness, Observed apnea, high blood Pressure-Body mass index, Age, Neck circumference and Gender) questionnaire was used to identify patients at high (score ${\geq}3$ out of 8) or low risk (score <3) of OSA. Results: Of the 517 patients, 165 (31.9%) snored during bronchoscopy under sedation. The prevalence of a STOP-Bang score ${\geq}3$ was 61.9% (320/517), whereas 200 of the 352 nonsnorers (56.8%) and 120 of the 165 snorers (72.7%) had a STOP-Bang score ${\geq}3$ (p=0.001). In multivariable analysis, snoring during bronchoscopy was significantly associated with a STOP-Bang score ${\geq}3$ after adjustment for the presence of diabetes mellitus, chronic obstructive pulmonary disease, chronic kidney disease, and stroke (adjusted odds ratio, 1.91; 95% confidence interval, 1.26-2.89; p=0.002). Conclusion: Two-thirds of patients undergoing bronchoscopy with moderate sedation were at risk of OSA based on the screening questionnaire. Snoring during bronchoscopy was highly predictive of patients at high risk of OSA.

• Progress in Superconductivity and Cryogenics
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• v.6 no.3
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• pp.1-5
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• 2004

This paper presents a study on the stability of bare and cu-laminated YBCO-coated conductor. we investigate the characteristics of quench/recovery behavior of YBCO test samples. bare and copper-laminated, by subjecting each test sample. immersed in a bath of liquid nitrogen boiling at 77.3 K. to a transport current pulse superimposed to a baseline DC current of 90-95% the critical current. The current pulse has an amplitude up to ∼4.5 times the critical current and a duration of 300 ms. This paper presents both experimental and simulation results.

• Journal of Korean Critical Care Nursing
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• v.4 no.1
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• pp.25-35
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• 2011

Purpose: The purpose of this study was to evaluate the actual outcomes of early discharge program for extremely low birth weight (ELBW) infants. Methods: Medical records of 122 ELBW infants admitted in the neonatal intensive care unit from January 2000 to June 2006 and those of their 112 mothers were analyzed retrospectively. Results: After being applied early discharge program to ELBW infants' mothers, their infants' lengths of stay, gestational age and body weight at discharge, duration of completion of oral feeding, number of emergency room visits after discharge were decreased and number of breast milk feeding was increased. Conclusion: Early discharge program for ELBW infants can be an effective intervention for parents and their ELBW infants contributing to neonatal nursing practices.

• Progress in Superconductivity and Cryogenics
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• v.7 no.3
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• pp.1-4
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• 2005

As high temperature superconductor applications became a reality due to increase in coated conductor performance, it is important to understand their stability behavior to design safe electrical power systems. Coated conductors can be stabilized with different metals and alloys for different types of application, to yield excellent electrical, thermal and mechanical performance. We have experimentally studied the dependence of quench and recovery characteristics of stainless steel stabilized coated conductors on the amplitude of current and duration time. Stability test of 3cm long sample were performed in a liquid nitrogen bath cooling condition by applying a short period over current pulses for 50 and 100ms, with amplitude up to ~6 times the critical current. The transport current that flows before and after the current pulse was fixed at about ~80-85% critical current. We analyzed the quench and recovery phenomena of the test sample using the current voltage characteristic.