• Nuclear Engineering and Technology
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• v.49 no.1
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• pp.54-70
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• 2017

The accumulator is a passive safety injection device for emergency core cooling systems. As an important safety feature for providing a high-speed injection flow to the core by compressed nitrogen gas pressure during a loss-of-coolant accident (LOCA), the accumulator injects its precharged nitrogen into the system after its coolant has been emptied. Attention has been drawn to the possible negative effects caused by such a nitrogen injection in passive safety nuclear power plants. Although some experimental work on the nitrogen injection has been done, there have been no comparative tests in which the effects on the system responses and the core safety have been clearly assessed. In this study, a new thermal hydraulic integral test facility-the advanced core-cooling mechanism experiment (ACME)-was designed and constructed to support the CAP1400 safety review. The ACME test facility was used to study the nitrogen injection effects on the system responses to the small break loss-of-coolant accident LOCA (SBLOCA) transient. Two comparison test groups-a 2-inch cold leg break and a double-ended direct-vessel-injection (DEDVI) line break-were conducted. Each group consists of a nitrogen injection test and a nitrogen isolation comparison test with the same break conditions. To assess the nitrogen injection effects, the experimental data that are representative of the system responses and the core safety were compared and analyzed. The results of the comparison show that the effects of nitrogen injection on system responses and core safety are significantly different between the 2-inch and DEDVI breaks. The mechanisms of the different effects on the transient were also investigated. The amount of nitrogen injected, along with its heat absorption, was likewise evaluated in order to assess its effect on the system depressurization process. The results of the comparison and analyses in this study are important for recognizing and understanding the potential negative effects on the passive core cooling performance caused by nitrogen injection during the SBLOCA transient.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.650-656
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• 2014

We propose a novel active fiber design for selectively generating cylindrical vector beams (CVBs) or cylindrical vector modes (CVMs) which can be applied to conventional fiber lasers. A fiber is designed to have a ring-shaped core refractive index profile which can lead to the best overlap between the active dopant distribution profile and the lowest-order CVM (LCVM) field profile. Therefore, the overlap factor (OVF) of the LCVM becomes even higher than that of the fundamental mode. We emphasize that this condition cannot be satisfied by a conventional step-index core fiber (SICF) but by the ring-doped core fiber (RDCF). Because the lasing threshold is inversely proportional to the OVF, the LCVM can predominantly be stimulated even without going through special procedures to impose extra loss mechanisms to the fundamental mode. We numerically verify that the OVF of the LCVM with the doped ions can significantly exceed that of the fundamental mode if the proposed fiber design is applied. In addition, an RDCF of the proposed fiber design can also operate in a regime containing no higher-order modes besides the LCVM, so that it can selectively and efficiently generate the LCVM without being disrupted by the parasitic lasing of the higher-order modes. We highlight that an optimized RDCF can lead to a >30 % higher OVF ratio than a SICF having the same doped area. The proposed model is expected to be useful for enhancing the efficiency of generating CVBs in an all-fiber format.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.14 no.4
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• pp.412-419
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• 2007

Purpose: This study was done to analyze core competencies affecting critical thinking ability of student nurses. Core competencies investigated in this study were problem solving ability, communication ability and self-directed learning ability. Method: Data were collected from a convenience sample of 322 student nurses in 2 provinces during the period from May 21 to June 8, 2007. Critical thinking, problem solving ability, communication ability and self-directed learning ability were measured using the Disposition towards Critical Thinking Scale by Park(1999-a) and the Core Competencies Scale by Lee(2003). Descriptive statistics and correlation coefficients with the SPSS WIN 12.0 program were used to analyze the data. Results: There were significant differences in the critical thinking according to grade, type of high school, experience with PBL, preference for lecture-based learning, preference for discussion and perceived logicality. The score for critical thinking showed significantly positive correlations with scores for problem solving ability(r=0.54, p=0.00), communication ability(r=0.56, p=0.00) and self-directed learning ability(r=0.54, p=0.00). Conclusion: The results of this study suggest that problem solving ability, communication ability and self-directed learning ability are significant factors affecting critical thinking in student nurses.

• Journal of the Korea Institute of Military Science and Technology
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• v.19 no.6
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• pp.789-796
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• 2016

In the Core Technology R&D of the defence area, the development of the related core element technology could be the foundation to develop advanced weapon system in the future. But it might make various problems if you can not accurately define the TRL of the element technology. In other words, if the technology is not sufficiently mature and then the project starts, it might require an increase in the development period and additional cost. Finally the system will be in an incomplete state and result in user dissatisfaction and the project failure. Therefore it is a very important task to properly assess the TRL for a successful project. In this study, We propose the method for risk management of core technology R&D project of the defence area using the QFD process with degree of difficulty and technology readiness level. It is also presented the process to determine the risk level using TRL and Degree of difficulty. Finally We apply this method to UGV system for verifying the result of this study.

• Journal of Powder Materials
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• v.24 no.2
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• pp.122-127
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• 2017

Fe-6.5 wt.% Si alloys are widely known to have excellent soft magnetic properties such as high magnetic flux density, low coercivity, and low core loss at high frequency. In this work, disc-shaped preforms are prepared by spark plasma sintering at 1223 K after inert gas atomization of Fe-6.5 wt.% Si powders. Fe-6.5 wt.% Si sheets are rolled by a powder hot-rolling process without cracking, and their microstructure and soft magnetic properties are investigated. The microstructure and magnetic properties (saturation magnetization and core loss) of the hot-rolled Fe-6.5 wt.% Si sheets are examined by scanning electron microscopy, electron backscatter diffraction, vibration sample magnetometry, and AC B-H analysis. The Fe-6.5 wt.% Si sheet rolled at a total reduction ratio of 80% exhibits good soft magnetic properties such as a saturation magnetization of 1.74 T and core loss ($W_{5/1000}$) of 30.7 W/kg. This result is caused by an increase in the electrical resistivity resulting from an increased particle boundary density and the oxide layers between the primary particle boundaries.

• The Journal of Korean Academic Society of Nursing Education
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• v.25 no.4
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• pp.448-458
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• 2019

Purpose: The aim of this study was to identify the effect of metacognition, communication skills, and confidence in the performance of core basic nursing skills on clinical competency in nursing students. Methods: A total of 158 students were recruited from two nursing colleges in B metropolitan city. Data were collected by means of self-reported questionnaires from December 3-31, 2018 and analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients and multiple linear regression with SPSS 21.0. Results: Metacognition, communication skills, and confidence in the performance of core basic nursing skills were higher than normal and the relationship between the variables metacognition (r=.69, p=<.001), communication skills (r=.69, p=<.001), and confidence in the performance of core basic nursing skills (r=.59, p=<.001) were highly positively correlated with clinical performance. Factors influencing these three variables accounted for 64.4% of clinical competency. Conclusion: Further research on the development of the curriculum and intervention program, and the verification of the effect are needed.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.798-798
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• 2006

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.2
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• pp.83-88
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• 2015

Core-A is 32-bit synthesizable processor core with a unique instruction set architecture (ISA). In this paper, the Core-A ISA is introduced with discussion of useful features and the development environment, including the software tool chain and hardware on-chip debugger. Core-A is described using Verilog-HDL and can be customized for a given application and synthesized for an application-specific integrated circuit or field-programmable gate array target. Also, the GNU Compiler Collection has been ported to support Core-A, and various predesigned platforms are well equipped with the established design flow to speed up the hardware/software co-design for a Core-A-based system.

• Journal of Pharmaceutical Investigation
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• v.40 no.2
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• pp.125-131
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• 2010

A bioequivalence study of LANIDIEM$^{(R)}$ tablet 4 mg (Samil. Co., Ltd.) to Vaxar$^{(R)}$ tablet 4 mg (GlaxoSmithKline Co., Ltd.) was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). Forty healthy male Korean volunteers were enrolled in the study and thirty six volunteers completed the study according to the protocol. Thirty six volunteers received each medicine at the lacidipine dose of 4 mg in a $2{\times}2$ crossover study. There was one week wash-out period between the doses. Plasma concentrations of lacidipine were monitored by a high performance liquid chromatography - tandem mass spectrometry (LC-MS/MS) for over a period of 24 hours after drug administration. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 24 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the crossover design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for LANIDIEM$^{(R)}$/Vaxar$^{(R)}$ were log 0.8102~log 1.0417 and log 0.8493~log 1.1439, respectively. These values were within the acceptable bioequivalence intervals of log 0.80~log 1.25. Thus, our study demonstrated the bioequivalence of LANIDIEM$^{(R)}$ tablet 4 mg and Vaxar$^{(R)}$ tablet 4 mg with respect to the rate and extent of absorption.

• Journal of Industrial Convergence
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• v.21 no.4
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• pp.81-89
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• 2023

This study try to confirm the relationship between clinical reasoning competence, critical thinking propensity, and confidence in performing core basic nursing skills among nursing students. The subjects of the study were 157 third and fourth year nursing students at D University in Daejeon, and the survey was conducted through a self-questionnaire from Nov. 2 to Nov. 15, 2022. The collected materials were analyzed using the SPSS/WIN26.0 program. The results showed the correlation between clinical reasoning competence and critical thinking propensity (r=.417, p<.001), clinical reasoning competence and core basic nursing performance confidence (r=.659, p<.001), critical thinking propensity and core basic nursing performance confidence (r=.303, p<.001). Therefore, the results of this study can be used as a basis for developing various curriculums to increase the confidence of nursing college students in performing core basic nursing techniques.