• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.25-30
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• 2011

Flow control of flow field is essential to design efficient elements relating to fluid machineries. In this study, flow characteristics of rectangular prism with center gap through-flow at different aspect ratio was investigated to flow control. It was used a FLUENT 6.3 version to study flow field. It was found that the through-flow disturbs the development of vertical velocity component and decreased the vortex size and critical value of a rapid change in pressure coefficient distribution.

• Journal of Korean Critical Care Nursing
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• v.4 no.2
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• pp.1-14
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• 2011

Purpose: This study was aimed to understand and describe the Korean critical care advanced practice nurses' work experience. Methods: Data was collected through 2 focus group interviews that were held in two different university hospitals in Seoul, Korea. All interviews were recorded and transcribed, and data were analysed using modified qualitative content analysis. Results: Ten themes were drawn from data analysis. They are "Various and complex tasks", "Excellency of advanced nursing practice", "Pressure and responsibility accompanied with pride", "Role identity confusion", "Role conflict", "Leaping and evolving role", "Gap between role and outcome evaluation", "Underestimated outcomes", "Where are my outcomes?" "Searching for outcomes: publicize the role". Conclusion: The results of this study help to understand the role of Korean critical care advanced practice nurses and to guide to outcome evaluation of their role effectiveness. Developing qualitative outcome indicators, cost-effectiveness ananlysis of Korean critical care advanced practice nurses' role, and accumulation of evidences through researches on outcome evaluation will be needed to successfully settle down advanced practice nursing in Korea.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.231-233
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• 2005

In this paper, we discuss the potential applications for electronic systems on flexible substrates. The barriers to the successful development of commercial markets are analyzed. For each promising application, the critical technical features are identified. Ways to bridge the gap between research and commercialization are suggested.

• International Journal of Highway Engineering
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• v.19 no.4
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• pp.61-68
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• 2017

PURPOSES : A complete signal system is not always the best solution for improving traffic operation efficiency at intersections. An alternative solution is to use a Protected Permitted Left Turn (PPLT) operation method. However, the PPLT method needs to be developed after a detailed study of driving tendencies, most notably the gap acceptance behavior, for successful implementation. In this study, the gap acceptance behavior was investigated under various variables and weather conditions, especially under rain, and the results were compared to the case of normal weather. The results of this study will be helpful in introducing the PPLT method, and are important considering the tendency of attempting unprotected left turns that is extremely common in Korean drivers. METHODS : Data was obtained by analyzing traffic footage at four intersections on a day when the precipitation was greater than 5 mm/h. The collected data was classified into seven variables for statistical analysis. Finally, we used logistic regression analysis to develop a probability distribution model. RESULTS : Gap, traffic volume, and the number of conflicting lanes were factors affecting the gap acceptance behavior of unprotected left turns under rainy conditions. CONCLUSIONS : The probability of attempting unprotected left turns is higher for larger gaps. On the other hand, the probability of attempting unprotected left turns decreases with an increase in the traffic volume. Finally, an increase in the number of conflict lanes leads to a decrease in the probability of attempting unprotected left turns.

• Laser Solutions
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• v.12 no.3
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• pp.14-17
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• 2009

The laser welding was performed for the flange joint of two overlapped coaxial circular pipes which serve as the inlet and connector pipes of STS 316L. The laser welding test finally resulted in a good penetration depth of 1.8 to 2.0 mm. On the way to get the good welding quality, two important parameters were found to be optimized. One is the focal positioning which is the offset of the laser beam focus to the exact welding seam line, which is more critical in the inner flange laser welding. When the beam spot size was deviated more than $200\;{\mu}m$ from the seam line, welding of two pipes is failed. The other is a gap size since a certain amount of gap is inevitable due to fabrication tolerance, or artificial allowances for smooth insertion of a pipe. However, it is required to restrict the gap allowance within 0.2mm to avoid undesirable undercut on a welding bead.

• Tuberculosis and Respiratory Diseases
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• v.60 no.5
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• pp.548-553
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• 2006

Background : Alcoholic ketoacidosis(AKA) is a metabolic disturbance that is caused by prolonged and excessive alcohol consumption. Though the prognosis is reportedly good, its outcome is unclear in some cases that are combined with multi-organ failure. There are few reports of an analysis of cases admitted to an intensive care unit(ICU) Method: Cases of AKA admitted to the ICU over the last 5 years were retrospectively analyzed. Severe AKA was characterized by multi-organ failure that required treatment in an ICU Results : All patients were males with a history of excessive alcohol consumption. Five of them (50%) mainly complained of gastrointestinal symptoms (nausea, vomiting, diarrhea), showing metabolic acidosis with an increased asmolar and anion gap. Rhabdomyolysis with acute renal failure was the most common combined organ failure. Mechanical ventilation was performed in 80%. Six patients died and 4 patients survived. In the surviving patients, the arterial blood gas analysis(ABGA) was normalized within 12 hours after admission. Conclusion : In severe AKA patients, rhabdomyolysis with acute renal failure was the most common complication. The mortality rate was high and death from shock occurred within 3 days.

• Progress in Superconductivity
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• v.9 no.2
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• pp.183-187
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• 2008

We have studied superconducting properties of $Mg_{1-x}Al_xB_2$ single crystals from reversible magnetization measurements. It was found that the upper critical fields $H_{c2}$ were decreased for both H // c and H // ab as Al is substituted for Mg. As a result, the large anisotropy of $H_{c2}$ observed in pure $MgB_2$, which is considered as one of the characteristics of two-gap superconductor, was decreased with Al doping. On the other hand, the irreversibility fields $H_{irr}$ were increased for x = 0.1 and were significantly decreased for x = 0.2. In contrary to the anisotropy of $H_{c2}$, the anisotropy of $H_{irr}$ was increased as Al concentration increases.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.10a
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• pp.190-190
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• 1999

CHF (Critical heat flux) on the external surface of the reactor vessel lower head is major key in the evaluation on the feasibility of IVR-EVC (In-Vessel Retention through External Vessel Cooling) concept. To identify the CHF on the external surface, considerable works have been performed. Through the review on the previous works related to the CHF on the external surface, liquid subcooling, induced flow along the external surface, ICI (In-Core Instrument) nozzle and minimum gap are identified as major parameters. According to the present analysis, the effects of the ICI nozzle and minimum gap on CHF are pronounced at the upstream of test vessel: on the other hand, the induced flow considerably affects the CHF at downstream of test vessel. In addition, the subcooling effect is shown at all of test vessel, and decreases with the increase in the elevation of test vessel. In the real application of the IVR-EVC concept, vertical position is known as a limiting position, at which thermal margin is the minimum. So, it is very important to precisely predict the CHF at vertical position in a viewpoint of gaining more thermal margins. However, the effects of the liquid subcooling and induced flow do not seem to be adequately included in the CHF correlations suggested by previous works, especially at the downstream positions.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.9
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• pp.442-445
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• 2006

In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBaCuO bulk superconductor with high mechanical strength and critical current density. In this project, the establishment of fabrication condition and additive effects of second elements were examined so as to improve the related properties to the practical use of YBaCuO superconductor, and we reported the production of the YBaCuO high Tc superconductor by the pyrolysis method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.2
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• pp.135-142
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• 2008

Experimental studies on the aerodynamic coupling effect on natural frequencies, critical speed and flutter instability of rotating disks are investigated in this paper. The theoretical analysis uses a fluid-structure model where the aerodynamic effects are represented in terms of elastic, lift and damping and stiffness components. The experiments performed using a vacuum chamber and ASMO/DVD disks rotating in vacuum, open and enclosure in several gaps with stationary wall give three main results. One is that the aerodynamic effect by the surrounding air reduces the natural frequencies and critical speeds of the vibration modes. The second is that natural frequency of disks rotating in open air is larger than that in enclosure. Finally, it is shown that the disk vibration is reduced as the gap between the disk and the rigid wall decreases.