• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.254-258
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• 2014

This paper presents the performance analysis results of a short line fault interruption of a gas circuit breaker, particularly a self-blast type breaker. Hot gas flow analysis was carried out using a CFD calculation combined with the arc model and nozzle ablation model. To evaluate the interruption performance, the index function was defined using the pressure in the heating chamber and the density above the arc region. The simulation and test results showed that the gas flow field and suitable choice of an interruption performance index can be used to predict the interruption characteristics and provide guidelines for designing self-blast breakers with a higher interruption capability.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1772-1774
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• 2004

Because the physics occurring during an interruption process is not well known, it is not easy to analyze the characteristics of a self-blast circuit breaker neither theoretically nor experimentally. Fortunately the available computational power and the numerical method improved recently make it possible to predict an interruption process as precisely and fast as possible. Therefore many researches using computational methods have been done for the interruption process of interrupters and applied to extend the information such as thermal and dielectric reignition. In this paper, we have simulated the interruption process of SF6 self-blast circuit breakers with the arc plasma during the fault interruption of a 10 kA current. The CFD program used here is coupled with the electromagnetic field analysis, the radiation model and the effects of turbulence. Through this work, we have get further information about the thermal performance as well as the behavior of the arc. The results have been compared with the measured arc voltage.

• Korean Journal of Occupational Health Nursing
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• v.30 no.2
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• pp.57-67
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• 2021

Purpose: This study was conducted to investigate the influence of professional self-concept, ego-resilience, and job stress on job performance in reemployed nurses after career interruption. Methods: The participants were 207 nurses who worked at hospitals with more than 100 beds located in Seoul, Gyeonggi and Gangwon provinces. The nurses had experienced a career interruption of at least one year, and had less than five years of experience at the current workplace. The collected data were analyzed utilizing SPSS 24.0 program and using descriptive statistics, t-test, ANOVA, Pearson correlation coefficients, and multiple regression. Results: The participants' job performance, professional self-concepts, ego-resilience, and job stress showed significant positive correlations. It was found that the professional self-concept, ego-resilience, and job stress had an effect on the participant's job performance in order, and explained 51.3% of variance in job performance. Conclusion: To improve the job performance of career disconnected nurses, it is necessary to reinforce job stress control, professional self-concept, and level of ego-resilience.

• The Journal of the Korea Contents Association
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• v.11 no.8
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• pp.378-387
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• 2011

This study was aimed to obtain basic data with the intention of lowering the motives of local university students' halting their studies through an analysis of the factors affecting their academic interruption and satisfaction with their campus life. The result of this study is as following. First, it was found that the factors affecting their academic interruption included social variables, sense of self-respect, educational services, home environment, personal interest, academic abilities and so on. It was noted that the factors of personal interest and self-respect had the most significant effects on their academic interruption, statistically. Second, it was shown that the factors such as self-respect, educational services and personal interest had significant effects statistically on satisfaction with their campus life. Third, it turned out that there were significant differences in satisfaction with their campus life between those who considered halting their studies and those who did not. Therefore, concrete efforts at the university level should be put into practice to enhance students' self-respect for and satisfaction with their universities.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.9
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• pp.24-32
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• 2020

A self-blast type gas circuit breaker has been studied in this study to improve efficiency of interrupting performance of short line fault(SLF). Hot gas flows of gas circuit breaker have been simulated to evaluate interruption performance using CFD. Design parameters such as various types of expansion chamber and nozzles are suggested by using simulation results. Simulated results and experimental ones are compared with previous (ones that of in under development and with capacitor) GCB. Modified new shape of an expansion chamber and nozzle has been suggested to improve the efficiency of gas flow and to provide guidelines for designing self-blast breaker with a higher interruption capability.

• Management & Information Systems Review
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• v.35 no.2
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• pp.13-26
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• 2016

The career management concept is changing rapidly in the career management field in recent years. It becomes very difficult to have a lifetime employment within the same firm. As there is career-interruption that is pervasive phenomenon in the career management area, many academics and practitioners have been interested in it. The purpose of this study was to examine the influence of career-interruptions as the effective career strategy of the self-directed career development on career strategy(career-interruptions frequency, career opportunities searching and career success (workers' wages). To test the effects of the self-directed career management, data were divided into two groups including self-directed career management group (n=210) and general career management group (n=191) based on whether career-interruptions are voluntary or not. The results showed that the self-directed career development attitude and career success were significantly different depending on worker's self-directed career management and general career management group.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.6
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• pp.673-677
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• 2004

We present the basic properties of a superconductive fuse (SF) based on YBCO/Au films. The SF consists of YBCO stripes covered with Au layers for current shunt. The fault current was limited to a designed value in less than 0.4 msec by resistance development in YBCO/Au upon quenching. This enabled the SF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, that is short enough to do self-interruption. Under the source voltage of 100 $V_{rms}$, the longer the duration time of fault current was, the shorter its discharge time was. The duration time of fault current and its discharge time were reduced by increased voltages in the range of 200 - 300 $V_{rms}$. We thought that this was because the quench propagation was limited by local melting generated with higher voltage.age.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.11
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• pp.519-526
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• 2005

This paper presents computer simulation results for developing new type of SF$_{6}$ Circuit Breaker in terms of cold gas flow after small current interruption. This cold gas flows down a nozzle into the chamber of a circuit breaker. There are many difficult problems in analyzing the gas flow due to complex geometry, moving boundary, shock wave and so on. When predicting the dielectric capability of a gas circuit breaker after interruption, the gas pressure and density distributions due to the cold gas must be considered in addition to the electrical field imposed across the gas. A self-coded computational fluid dynamics (CFD) program is used for the simulation of cold gas flow in order to evaluate the electrical field characteristic across open contacts and transient characteristics of insulations after small current interruption.

• Journal of Digital Convergence
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• v.19 no.6
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• pp.373-385
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• 2021

In this study, the Korea Youth Policy Institute applied a self-registering model to verify the patterns of parental stress, multicultural youth psychological maladjustment, and interdependence between three factors by using five-point-time data tracked from middle school to high school. According to the analysis, First, Parent' stress at the time of the five surveys had a significant positive effect on the psychological maladjustment and the risk of academic interruption of multicultural adolescents at that point. Second, the psychological maladaptation of multicultural adolescents at the time of the previous five surveys had a significant positive effect on the risk of academic interruption at that point. Based on these analysis results, various support measures were proposed to cope with the stress of multicultural youth parents, and policy alternatives were proposed to prevent the risk of academic interruption by reducing the psychological maladjustment of multicultural youth.

• Proceedings of the Korean Vacuum Society Conference
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• 2007.08a
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• pp.68-68
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• 2007