• Journal of The Korean Astronomical Society
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• v.29 no.spc1
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• pp.31-33
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• 1996

The role of gravitational lenses as valuable tools for astrophysics and cosmology is highlighted.

• Korean Journal of Environmental Agriculture
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• v.36 no.4
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• pp.288-292
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• 2017

BACKGROUND: Silicon tetrachloride reacts with moisture in the atmosphere to generate hydrogen chloride, which affects the environment. Since silicon tetrachloride and its by-products are dispersed in the atmosphere in a short time after the silicon tetrachloride release into the atmosphere, it is difficult to directly assess the extent of environmental impact. In the present study, the exposure test of silicon tetrachloride or hydrogen chloride was examined in order to establish the criterion of the range affected by the silicon tetrachloride release, and the actual crops in the area exposed to silicon tetrachloride leakage were analyzed. METHODS AND RESULTS: For the experiment of exposure to silicon tetrachloride or hydrogen chloride, the leaves of red-pepper and corn were used in glass sealed containers. In the actual accident area, 59 samples from 10 different kinds of crops were collected. The pretreatment of the sample was performed by freezing and grinding, and then extracted using distilled water. The pH and concentration of chloride ($Cl^-$) ion of the extracted solution were measured using pH meter and ion chromatograph, respectively. CONCLUSION: Exposure to silicon tetrachloride caused visible damage, increasing the concentration of chloride ion, and decreasing the pH as well as hydrochloric acid. In the actual crops of the affected area, the tendency was the same as the result of the laboratory test, and the range of influence could be estimated through the concentration of $Cl^-$ ion over 2,000 mg/kg, and the correlation evaluation between the concentration of $Cl^-$ and pH. Therefore, the concentration of $Cl^-$ ion and the correlation between $Cl^-$ and pH would be considered as the factors to estimate the influence range of silicon tetrachloride release.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.197-206
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• 2016

Introduction: This study aims to investigate the effects of acupuncture stimulation on the radial artery's pressure pulse wave, along with various hemodynamic parameters, and to explore the possible underlying mechanism of pulse diagnosis in healthy participants in their twenties. Methods and analysis: This study is a prospective, single-arm, exploratory clinical study. A total of 25 healthy participants, without regard to gender, in their twenties will be recruited by physicians. Written informed consent will be obtained from all participants. The participants will receive acupuncture once at ST36 on both sides. The radial arterial pulse waves will be measured on the left arm of the subjects by using an applicable pulse tonometric device (KIOM-PAS). On the right arm (appearing twice), electrocardiogram (ECG), photoplethysmogram (PPG), respiration and cardiac output (CO) signals, will be measured using a physiological data acquisition system (Biopac module), while the velocity of blood flow, and the diameter and the depth of the blood vessel will be measured using an ultrasonogram machine on the right arm (appearing twice). All measurements will be conducted before, during, and after acupuncture. The primary outcome will be the spectral energy at high frequencies above 10 Hz ($SE_{10-30Hz}$) calculated from the KIOM-PAS device signal. Secondary outcomes will be various variables obtained from the KIOM-PAS device, ECG, PPG, impedance cardiography modules, and an ultrasonogram machine. Discussion: The results of this trial will provide information regarding the physiological and the hemodynamic mechanisms underlying acupuncture stimulation and clinical evidence for the influence of acupuncture on the pressure pulse wave in the radial artery. Ethics and dissemination: This study was approved by the Institutional Review Board (IRB) of Kyung Hee University's Oriental Medical Center, Seoul, Korea (KOMCIRB-150818-HR-030). The study findings will be published in peer-reviewed journals and presented at national and international conferences. Trial registration number: This trial was registered with the Clinical Research Information Service (CRIS) at the Korea National Institute of Health (NIH), Republic of Korea (KCT0001663), which is a registry in the World Health Organization's (WHO's) Registry Network.

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3635-3642
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• 2021

Natural circulation systems (NCSs) are extensively applied in nuclear power plants because of their simplicity and inherent safety features. For some passive natural circulation systems in floating nuclear power plants (FNPPs), the ocean is commonly used as the heat sink. Condensation induced water hammer (CIWH) events may appear as the steam directly contacts the subcooled seawater, which seriously threatens the safe operation and integrity of the NCSs. Nevertheless, the research on the formation mechanisms of CIWH is insufficient, especially in NCSs. In this paper, the characteristics of flow rate and fluid temperature are emphatically analyzed. Then the formation types of CIWH are identified by visualization method. The experimental results reveal that due to the different size and formation periods of steam slugs, the flow rate presents continuous and irregular oscillation. The fluid in the horizontal hot pipe section near the water tank is always subcooled due to the reverse flow phenomenon. Moreover, the transition from stratified flow to slug flow can cause CIWH and enhance flow instability. Three types of formation mechanisms of CIWH, including the Kelvin-Helmholtz instability, the interaction of solitary wave and interface wave, and the pressure wave induced by CIWH, are obtained by identifying 67 CIWH events.

• The Journal of Korean Medicine
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• v.38 no.1
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• pp.21-33
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• 2017

Objectives: The purpose of this study is to present the needs for New Health Technology in Korean medicine field and suggest the strategy to raise the application and selection rate. Methods: In this study, we reviewed the application status of New Health Technology application from April 27, 2007 to June 30, 2016. And we analyzed the assessment methods, procedures, and failure factors through the two Research stage technologies reports in Korean medicine field. Results: In Korean medicine field, the application status of New Health Technology is very small as 2% of the whole applications. Moreover, 62.9% of the applied technology were either an existing technology or an early technology, so did not enter the assessment process. Two technologies categorized as Research stage technology also had failed to adopt New Health Technology because they were lacking evidences or need more research to prove effectiveness. Conclusions: In order to develop New Health Technology in Korean medicine, more efforts should be made to activate research that can prove the safety and effectiveness of medical technology, and to create a quantitative or qualitative basis for the results of the research. Also, it is necessary to increase researchers' awareness of New Health Technology. And the strategy to positively utilize the "Limited Approval" to promote clinical studies.

• Journal of Radiation Protection and Research
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• v.41 no.1
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• pp.15-29
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• 2016

Research background: Despite the visible growth in radiation usage and nuclear power development, the analysis of their relationship with fundamental rights, a subject of public concern regarding issues including the right to health, environmental rights, safety rights, the right to know, the right to development, and the right to life, is currently non-existent. Methods: By examining various fundamental rights in the context of positive laws regarding radiation and nuclear power in an idealistic perspective that guarantees the maximum degree of rights, this paper aims to propose legislative supplements that will lead to improvements in quality of life. Result and discussion: In the South Korean Constitution, radiation and nuclear power is a subject incorporating several rights, including at least 12 clauses that are directly related to fundamental rights; these constitutional rights are manifested in the various clauses of the 14 positive laws regarding radiation and nuclear power. The question on the relative importance of each fundamental right as reflected in these positive laws- whether the right to life should be prioritized or considered equal in weight to the right to health, environmental rights, the right to know, and safety rights- requires careful deliberation and is difficult to humanly resolve in the short term. Conclusion: Making policy that expands the usage of radiation and nuclear power while simultaneously preventing their associated risks is an important task for the Republic of Korea, and a proper value judgment is necessary to find a balance in its associated rights.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1164-1171
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• 2020

T-junction structures play an important role in nuclear power plant systems. Research on liquid entrainment is mostly based on small-scale branch pipes (d/D ≤ 0.2) and attention paid to large-scale branch pipes (0.33 < d/D < 1) is insufficient. Accordingly, this study implements a series of experiments on the liquid entrainment of T-junction with different angles (32.2°,47.9°,62.3°,90°) through a large-scale branch (d/D = 0.675). The onset liquid entrainment is related to the gas phase Froude number Fr_g, the dimensionless gas chamber height h_b/d and the branch pipe angle 𝜃. As Fr_g increases, h_b/d also rises. With a constant h_b/d, the onset liquid entrainment changes from droplets entrainment by the gas phase to that by the rising liquid film. The steady-state liquid entrainment is related to w_3g, h/d and 𝜃. With constant w_3g and h/d, the branch quality grows as the branch angle increases. With a certain h/d, the branch quality increases, as the w_3g number increases.

• Korean Journal of Human Ecology
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• v.18 no.3
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• pp.583-595
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• 2009

The study was to see if the perceptions of pre-service kindergarten teacher toward the education of children's fundamental habit would show different characteristics based on their school type, education learning experience, and practicum experience. Subjects were 200 students majoring in early childhood education who were attending 3-year colleges and 4-year universities in Jellabuk-do and Daejeon. Preceding researches were referenced to develop questionnaire for the research method. The collected data was analyzed through t-test and Chi-square test. The followings are results: First, the interest in education showed significant difference in school type, but not significant difference in education learning experience and practicum experience. Second, the recognition in educational goal showed significant difference in practicum experience, but not significant difference in school type and education learning experience. the educational content showed significant difference in education learning experience, but not in school type and practicum experience. the recognition in educational principal showed significant difference in school type, but not significant difference in education learning experience and practicum experience. the recognition in educational method showed no significant difference in school type, education learning experience and practicum experience. Third, the recognition in educational hardship toward teaching showed significant difference in school type, education learning experience and practicum experience. The results of study would provide the righteous cognitive establishment of children's fundamental habit education and serve the appropriate guidelines being professor for our perspective kindergarten teachers. Also, they would be utilized as basic information to plan the direction of children's fundamental habit education to develop the program of children's life guidance.

• The Journal of the Korea Contents Association
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• v.21 no.9
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• pp.714-722
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• 2021

In this study, intends to propose virtual reality education contents for fundamental nursing skills to develop various teaching methods in nursing education. Blood sugar test & insulin subcutaneous injection among the 20 core fundamental nursing skills is one of that frequently performed and can be used for self-management education for diabetic patients. This study designed a core fundamental nursing skill on immersive VR contents by dividing the learner's experience into three stages: guide, mission, and feedback with these skills. And it is designed by tracking the movement of the hand through finger joint recognition without using a controller for immerse in training. This study will help develop VR nursing education contents that can improve clinical practice competency and the effect of the nursing education.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.148-163
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• 2021

Timely fault identification is important for safe and reliable operation of the electric valve system. Many research works have utilized different data-driven approach for fault diagnosis in complex systems. However, they do not consider specific characteristics of critical control components such as electric valves. This work presents an integrated shallow-deep fault diagnostic model, developed based on signals extracted from DN50 electric valve. First, the local optimal issue of particle swarm optimization algorithm is solved by optimizing the weight search capability, the particle speed, and position update strategy. Then, to develop a shallow diagnostic model, the modified particle swarm algorithm is combined with support vector machine to form a hybrid improved particle swarm-support vector machine (IPs-SVM). To decouple the influence of the background noise, the wavelet packet transform method is used to reconstruct the vibration signal. Thereafter, the IPs-SVM is used to classify phase imbalance and damaged valve faults, and the performance was evaluated against other models developed using the conventional SVM and particle swarm optimized SVM. Secondly, three different deep belief network (DBN) models are developed, using different acoustic signal structures: raw signal, wavelet transformed signal and time-series (sequential) signal. The models are developed to estimate internal leakage sizes in the electric valve. The predictive performance of the DBN and the evaluation results of the proposed IPs-SVM are also presented in this paper.