• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.191-192
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• 2014

Multiple output converters (MOCs) are widely used for applications which require various levels of the output voltages due to their benefits in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, a novel Time Division Multiple Control (TDMC) method to regulate all the outputs in high precision is proposed and applied for the multiple output battery charger based on the phase shift full bridge topology to charge a multiple number of batteries at one time. The proposed converter can charge three different kinds of batteries or same kind of batteries in different state of charges (SOCs) by using constant current/constant voltage (CC/CV) charge mode independently. At the same time it can provide an even degree of tight regulation for each output to satisfy the strict ripple requirement of the battery. The validity and feasibility of the proposed method are verified through the experiments.

• 임상간호연구
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• 제16권3호
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• pp.133-144
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• 2010

Purpose: This study intended to evaluate the intermediate effects of using Electronic Nursing Record System which was introduced 4 years and 4 months ago. Methods: Participants were 65 nurses engaged in 3 shifts in a general hospital. The specific methods were identification of nursing activity times by means of nurses' self-recording in structured forms, survey of user satisfaction using questionnaires, and examination of nurses' responses to open-ended questions about using the system. Results: The direct nursing activities took more than 50% of the time during day and evening shifts. In night shift, direct nursing activities took more than 41% of the time. Comparing to the initial evaluation, measured at 10 months after the introduction, the time spent in indirect nursing activities have decreased about 10% in each shift. The user satisfaction was 3.54 points which was higher than 3.33 points measured at 10 months after the introduction. The nurses recommended some changes needed in the current system to make it better, such as speeding up the system. Conclusion: The intermediate evaluation shows reduced indirect nursing time, increased direct nursing time, and improved user satisfaction.

• Current Photovoltaic Research
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• 제7권2호
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• pp.29-32
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• 2019

Large band gap attenuation of CdS nanoclusters in hybrid sol gel matrix comprised of 3-(trimethoxysilyl)propyl methacrylate (TMSPM), 15 wt. % zirconium, and various amounts of cadmium acetate was observed after $H_2S$ exposure. Hybrid sol gel matrixes were prepared by hydrolysis and condensation reactions. The sol gels contained with various amount of cadmium acetate were spin coated to glass substrates and exposed to $H_2S$ gas. The UV-visible absorption peaks were shifted toward blue with increasing the amount of CdS nanoclusters and were shifted to the red after thermal process. Significant amount of -OH absorption peaks were reduced after thermal process. Strong room temperature photoluminescence (PL) of CdS nanoclusters was observed after exposing to $H_2S$ gas. The PL intensity increased for several minutes and slowly decreased thereafter. The luminescence peaks were continuously shifted toward blue as the time passed. Extraordinary Stokes shift (approximately 160 nm) was observed.

• 임상간호연구
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• 제25권2호
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• pp.107-119
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• 2019

Purpose: The purpose of this study was to investigate the welfare status of nurses and the status of fixed night shifts and flexible work arrangements in both general hospitals and advanced general hospitals in Korea. Methods: A total of 167 hospitals participated in this study, done from April to October 2018. Results: There were 103 hospitals utilizing the fixed night shift system, 22 in the two-shift system, 3 in the fixed holiday shift, 79 in the fixed shift system, and 39 in the short-time working system. The average welfare benefits for nurses increased to 33.02 million won on average. However, welfare services for the nurses were poor: 41.8% of the respondents had a nurses' lounge, 81.7% were given dormitory space at their place of employment, 41.8% had access to welfare facilities, and 56.4% were provided with welfare support countermeasures. Conclusion: The results show an increasing trend of hospitals to utilize fixed night shift and flexible work arrangements. An institutional strategy at the national policy level should be established to implement flexible work arrangements including the fixed night shift system, which has a poor level of welfare.

• 가정∙방문간호학회지
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• 제30권1호
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• pp.15-25
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• 2023

Purpose: This study describes the associations between shift work factors, workplace violence bystander types, and the missed nursing care of hospital nurses. Methods: A cross-sectional survey was conducted among hospital nurses using structured questionnaires related to shift work factors, workplace violence bystander types, and missed nursing care. The study participants were 199 nurses caring for adult patients and working in two tertiary hospitals. Results: The missed nursing care of the participants showed a statistically significant positive correlation with the facilitating bystander (r=.40, p<.001) and abdicating bystander (r=.28, p<.001) among the workplace violence bystander types. However, rest time during duty showed a significant negative correlation (r=-.16, p=.026). A regression model with control variables (department and clinical career), shift work factors, and workplace violence bystander types explained approximately 25% of missed nursing care of the study participants. Further, the facilitating bystander type influenced the missed nursing care of hospital nurses. Conclusion: As a result of examining the associations between shift work factors, workplace violence bystander types, and missed nursing care of hospital nurses, it was confirmed that missed nursing care was influenced by the facilitating bystander type. It is necessary to improve the nursing culture within the department so that nurses do not behave as negative bystanders to workplace violence.

• Journal of applied mathematics & informatics
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• 제5권1호
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• pp.1-12
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• 1998

We consider G/M/1 queues with multiple vacation disci-pline where at the end of every busy period the server stays idle in the system for a period of time called changeover time and then follows a vacation if there is no arrival during the changeover time. The vaca-tion time has a hyperexponential distribution. By using the methods of the shift operator and supplementary variable we explicitly obtain the queue length probabilities at arrival time points and arbitrary time points simultaneously.

• 한국광학회지
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• 제8권3호
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• pp.213-217
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• 1997

n형과 p형 GaAs의 도핑에 따른 형광과 시간 분해 형광특성을 조사하였다. 도핑의 농도가 증가할수록 형광의 피크 위치는 p형은 낮은 에너지 쪽으로, n형은 높은 에너지 쪽으로 이동함을 관찰하였다. 이것은 p형은 띠간격 좁아짐 효과가 우세하게 작용하며, n형은 Burstein-Moss효과가 지배적으로 작용하기 때문인 것으로 해석된다. 또한, 도핑의 농도가 증가하면 형광의 소멸시간과 상승시간이 감소하며, p형의 형광소멸시간과 상승시간이 n형보다 더 빠르게 나타났다. 따라서 도핑된 GaAs에서 형광소멸시간과 상승시간은 다수 운반자의 종류와 농도에 의존함을 알 수 있으며, 운반자-운반자 상호작용이 에너지 이완 과정에 중요한 역할을 함을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제22권7호
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• pp.580-583
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.81-82
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• 2009

This paper introduces a gate drive IC for power modules with shoot-through immunity. A new approach uses a bootstrap diode as a high-side voltage bias and a level shift function at the same time. Therefore, the gate drive circuit becomes a simple and low-cost without conventional level shift functions such as HVIC(High-Voltage IC), optocoupler and transformer. The proposed gate drive IC is designed and fabricated using the Dongbu-Hitek's 0.35um BD350BA process. It has been tested and verified with IGBT modules.

• 한국광학회지
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• 제11권1호
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• pp.33-36
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• 2000

일반적으로 광섬유 격자에 사용되고 있는 KrF 엑시머 레이저를 광출력 스펙트럼 파장천이용으로 이용하였다. 실험 결과, FHD에 의해서 제작된 PLC형 WDM 방향성결합기에서는 UV에 의한 파장천이효과가 비교적 큼을 알 수 있었다. UV 노출량에 의한 파장천이량을 측정하여 UV 노출량에 따른 실리카 광도파로의 유효굴절률 변화량을 계산하였다.