• 한국초전도학회:학술대회논문집
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• v.15
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• pp.75-75
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• 2005

• Journal of Energy Engineering
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• v.7 no.1
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• pp.44-56
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• 1998

Separate heat pipe exchanger is considered as the high thermal transportation equipment, because evaporator and condenser are separately positioned in the long distance. Its characteristics are that the working fluid is circulated naturally by the position height of two exchangers. But the operating characteristics are restricted by the temperature of hot and cold fluid, flow pattern and diameter of vapor line, etc. in this study, the vapor pressure and the minimum height of two exchangers are studied about the factors restricting the operating characteristics.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.881-886
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• 2003

In spite of its simple design, structure and operating mechanism, swing check valves are one of the critical components which adversely affect the safety of the nuclear power plants if they fail to function properly. Therefore, it is important to evaluate the performance condition of the swing check valves in safety-related systems. The performance characteristics of swing check valves include opening characteristics, the minimum required flow velocity, the pressure drop at design flow, the disc stability, and the effect of the upstream disturbances. Among factors to identify the performance of a swing check valve, a method to evaluate the opening characteristics and the minimum required flow velocity, which guarantees to fully open the disc and hold the disc without motion, are presented to determine the operating region of the swing check valve, such as stable, tapping, or oscillation. Based on the determined operating region and opening characteristics, the simple methods of wear and fatigue analyses of the specific parts of the valve are also described.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.53-61
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• 2013

This paper propose a improved operating characteristics of the 5-phase 5kW within developed the surface permanent mount synchronous generator (SPMSG) in order to make a study of a polyphase ac motors keeping hold of more advantages. The developed manufacturing motor was necessary to do improvement of voltage regulation, efficiency, operating characteristics, and so on at the rated load. There are remake a redesigned and distributed stator winding connection without changing the frames of stator and rotor core in previous established generator by a repeat tests. There are shown a amplitude and waveform of the generated electromotive force, FFT analysis of harmonics within output voltages, and reviewing a experiment results in load of resistive and 5-phase induction motor by variable generator output frequency.

• Fire Science and Engineering
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• v.25 no.2
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• pp.107-113
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• 2011

This paper presents the results of artificially accelerated aging characteristics of the rate of rise spot type heat detectors. This experiment carried out to investigate the detector's operating characteristics when a fire was broken out or the regular tests were performed. The result showed that the delay of operating time or no-operation of heat detector which was made by company B and used in the field for 5 years may be occurred even at the $100^{\circ}C$. This result is due to the leakage of inflated air from heat chamber. However the operating display LED was not out of order, even if the temperature was increased up to $160^{\circ}C$.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.8 no.1
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• pp.25-32
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• 2012

Korea Hydro & Nuclear Power Co. (KHNP) has developed and implemented the maintenance effectiveness monitoring (MR) programs for the operating nuclear power plants. The MR program is developed by reflecting design characteristics of the operating nuclear power plants to monitor the plant performance for improving the safety and reliability. Recently, KHNP has built a new nuclear power plant, and developed the MR program to establish the advanced maintenance system by reflecting unique design characteristics based on the OPR1000 standard model. So, the MR program developed in this study has another characteristics in comparison with the OPR1000 standard model, and we will verify the suitability of the MR program through evaluating initial performance of the plant. The safety and reliability of the new plant will be improved by developing and implementing the MR program.

• Archives of design research
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• v.4 no.1
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• pp.39-50
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• 1991

Recently, the society is being, developed physically and technically and the desire for the better equipped office environment has been required. Due to the change of recognition about the information-oriented office and the rapid progress ot the office automation many conventional office environment are changing to the new phase, the intelligent building. Unfortunately, because of the lack of the harmony between our business operating characteristics and the western office space planning, there are some severe problems in improving the business ability. To create the efficent office environment design, we have to understand the function of the western office space and our current phenomenon, appearing in the company. Thus, the goal of this study is to present the methodology for improving the office environmental design by analizing the following elements. - The concept of the office space - The historical frame of the office development - The consideration of the office characteristics - The Analysis of the business working Characteristics, organizing characteristics, and operating characteristics

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.1
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• pp.81-90
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• 2016

Different from general operating policies to be applied for controllable queueing models, two of three well-known simple N, T and D operating policies are applied alternatingly to the single server controllable queueing models, so called alternating (NT), (ND) and (TD) policies. For example, the alternating (ND) operating policy is defined as the busy period is initiated by the simple N operating policy first, then the next busy period is initiated by the simple D operating policy and repeats the same sequence after that continuously. Because of newly designed operating policies, important system characteristic such as the expected busy and idle periods, the expected busy cycle, the expected number of customers in the system and so on should be redefined. That is, the expected busy and idle periods are redefined as the sum of the corresponding expected busy periods and idle periods initiated by both one of the two simple operating policies and the remaining simple operating policy, respectively. The expected number of customers in the system is represented by the weighted or pooled average of both expected number of customers in the system when the predetermined two simple operating policies are applied in sequence repeatedly. In particular, the expected number of customers in the system could be used to derive the expected waiting time in the queue or system by applying the famous Little's formulas. Most of such system characteristics derived would play important roles to construct the total cost functions per unit time for determination of the optimal operating policies by defining appropriate cost elements to operate the desired queueing systems.

• Journal of Korean Academy of Nursing Administration
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• v.22 no.5
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• pp.471-479
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• 2016

Purpose: This study was conducted to evaluate the level of safety climate, fatigue, and safety performance and to identify the impact of safety climate and fatigue on the safety performance of operating room nurses. Methods: The study design was a descriptive survey. Participants were 174 operating room nurses from two general hospitals and two university hospitals in S and D cities. Three structurally designed questionnaires were used to evaluate their safety climate, fatigue, and safety performance. Collected data were analyzed using descriptive analysis, t-tests, ANOVAs, Pearson correlation coefficient, and stepwise multiple regression. Results: Safety performance of operating room nurses had a mean of 3.26 on a 5-point scale. 'Current department career'(${\beta}=.17$, p=.006) and 'safety climate (work-unit contribution) (${\beta}=.63$, p<.001) accounted for 39% of the variance in operating room nurses' safety performance. Conclusion: Findings indicate that work-unit contribution towards safety climate is an important factor in increasing operating room nurses' safety performance. Therefore, it is essential to find motivational properties consistent with the characteristics of the operating room environment.

• Tribology and Lubricants
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• v.39 no.4
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• pp.123-132
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• 2023

In this study, the expansion, stress, and operating clearance of bearing elements during operation are observed using the inner/outer ring temperature test data of a 3.0×10⁶ DN-class roller bearing. The operating clearance characteristics of inner-/outer-ring cooling (IORC) bearings are compared to those of inner-ring cooling (IRC) bearings. For IRC bearings, the thermal expansion of the outer ring is the most important factor in clearance variation. As a result, the operating clearance is less than the initial clearance of 61 ㎛, and the operating clearance decreases to 0.5 ㎛ at 25,500 rpm. Conversely, the temperature of the outer ring of IORC bearings is lower than that of IRC bearings, so the operating clearance is kept smaller. When the coolant flow rate to the outer ring is approximately 1.5 to 2.0 L/min, the temperature difference between the inner and outer rings is minimized and the operating clearance is maintained at a significantly lower level than IRC bearings. Small operating clearances are expected to be effective in reducing cage slip and skid damage in roller bearings. The results and analysis procedures of this study can be utilized to design of bearing clearance, lubricant flow rate, and assembled interference in the early design stage of aerospace roller bearings.