• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.254.1-254.1
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• 2008

• Progress in Superconductivity
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• v.4 no.2
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• pp.176-179
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• 2003

A lot of efforts have been focused on the optimization of PIT parameters for Bi-2223/Ag wire. Bi-2223 superconducting wires with 55 filaments were fabricated by stacking, drawing process. Before rolling process, round wires were pre -annealed at 760 - 820 $^{\circ}C$ and low oxygen partial pressure. We confirmed that pre-annealing step was to transform Bi-2212 orthorhombic structure from Bi-2212 tetragonal structure and to reduce the formation of second phases. However Bi-2223 phases also were formed at higher than 76$0^{\circ}C$ of pre-annealing temperature. The engineering critical current densities (Je) of Bi-22231Ag tapes were sintered at low oxygen partial pressure were higher than t hat of the wires sintered at air. We could achieve 6500 A/${cm}^2$ of Je for the tape that was initially kept at slightly higher temperature than that of normal heat treatment.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1094_1095
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• 2009

최근 분산전원 시스템들이 가정이나 공공기관 등에 많이 설치되면서 계통에 많은 문제점을 일으키고 있다. 이러한 문제점을 연구하기 위해서는 계통 등의 실제 시스템을 설치하여 실험을 하여야 하는데 학교 연구실 입장에서는 실제 시스템을 설치하여 실험하는데 한계가 있다. 그러나 실시간 전력 계통 모의장치 (Real Time Digital Simulator)를 이용하여 실시간으로 시스템을 시뮬레이션 할 경우 다양한 알고리즘의 적용이 가능하고, 고장, 전력계통 과도현상 등 계통에 일어날 수 있는 여러 가지 상황을 손쉽게 고려해 보는 것이 가능하다. 본 논문에서는 RTDS 내 계통 연계형 태양광 발전시스템을 실제 시스템과 유사하게 모델링하고, 실제 DSP (Digital Signal Processor) 를 이용하여 시스템을 실시간으로 운전하는 HILS (Hardware In the Loop System) 시스템을 구성하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.6
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• pp.479-484
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• 2019

Environmental problems were related to human life from second industrial revolution. Recently, peoples are interested in solving global warming problem and improving air quality. Therefore, we request for eco-friendly vehicles such as fuel cell electric vehicles using eco-friendly hydrogen energy. In order to reduce particulate matter in Korea, we have established a plan to promote the deployment of eco-friendly vehicles. In this paper, we analyzed the average monthly charging status and hydrogen consumption by introducing fuel cell bus.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.4
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• pp.293-300
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• 2022

The Changwon city which announced 2040 hydrogen policy vision is planning to establish the new hydrogen-centered city. The building of plant which is available to produce the 5 ton/day of liquid hydrogen is promoted as one of the projects in order to achieve the vision. However, the analysis in terms of local economic and environmental aspects is insufficient because this liquid hydrogen plant is the first in Korea. Therefore, in this study, the financial feasibility of the liquid hydrogen plant project was analyzed by reviewing the benefits of liquid hydrogen supply and environmental improvement, and the feasibility of this project has been investigated which is being built based on the hydrogen industrial plan of Changwon city.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.114-118
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• 2017

Dermoid cysts are benign congenital tumors composed of keratinizing squamous epithelium and dermal derivatives. They account for less than 1% of all intracranial tumors and are rarely exhibited at the base of the skull. To the best of our knowledge, only one case report has presented computed tomography and conventional T1-weighted magnetic resonance (MR) findings that revealed an infratemporal dermoid cyst. In the present study, we report an unusual case of a dermoid cyst in the right infratemporal fossa, which was incidentally detected by MR imaging with the Dixon technique. This article also highlights the importance of meticulous radiological review and the usefulness of the Dixon technique in everyday clinical practice.

• Korean Journal of Health Education and Promotion
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• v.14 no.1
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• pp.63-72
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• 1997

In order to develop the programme for the improvement of dental health among primary school children, epidemiological survey to examine dental caries status was conducted among primary school children in Changwon, Korea. We sampled 2 primary schools and surveyed children from first to sixth grade aged 6-11 years. All samples were 3,206 consisted of 1,715 males and 1,491 females. We assessed caries prevalence on permanent teeth. 1. Children with caries experience on permanent teeth were 15.1% at 1st grade, 48.2% at 2nd grade, 73.8% at 3rd grade, 75.6% at 4th grade, 76.8% at 5th grade, 77.4% at 6th grade. 2. Decayed, Missing and Filled teeth were 0.31 at 1st grade, 1.16 at 2nd grade, 2.12 at 3rd grade, 2.38 at 4th grade, 2.50 at 5th grade, 2.69 at 6th grade. 3. Decayed teeth among Decayed, Missing and Filled teeth were totally 63.4%. Filled teeth among Decayed, Missing and Filled teeth were totally 36.6%. 4. Community dental health programmmes including water fluoridation, fluoride mouth rinsing, use of fluoride-containing toothpastes and fissure sealants should be developed to prevent dental caries among school children. 5. School incremental dental care programme should be also developed to prevent and treat children's dental caries by use of dentists and oral hygienists.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.4
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• pp.356-361
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• 2019

Since the government announced the roadmap to revitalize the hydrogen economy, we are constantly making the effort to expand the use of fuel cell electric vehicles (FCEV) and hydrogen charging stations. There is however a significant issue to build and operate the hydrogen charging station due to the lack of the profit model. Many researchers believe that the supply of FCEV will be increased in the near future and finally ensure the economy of hydrogen charging stations. This study shows that the sales changes of hydrogen gas and consumption patterns by the operation of the hydrogen charging station in Changwon City. The results will be used as the evidence to support for operating the hydrogen charging station by private businesses and the validity of additional establishment of hydrogen charging stations.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.169-177
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• 2009

In the past decade there has been increasing concern about the atopic dermatitis (AD) associated with environmental diseases. AD has been increased in the last decade and known as one of the multifactoral diseases, which has the genetic background and environmental factors at the same time. The purposes of this study were to investigate the prevalence rate and etiologic risk factors of atopic dermatitis in preschool children in Changwon, which is a one of the Korean cities and has a large industrial complex. We reviewed and analyzed the statistical data, obtained from Korea National Health Insurance Corporation, related to prevalence rate by age and administrative district. A cross-sectional questionnaire survey, based on ISAAC (International Study of Allergy and Asthma in Childhood), was conducted on random samples of preschool children (5 to 8 years old) of large sized kindergartens in Changwon. The lifetime and last one years prevalence of AD in preschool children in Changwon was increased from 1998 to 2008. The prevalence rate of AD in the preschool children in Changwon city was 9.6%. The prevalence rate in boys was 9.7% and that in girls was 9.4%. The one year prevalence of AD was ranked as middle among other provincial cities in Korea in 2008. This study showed that the prevalence rate of the atopic disease in Changwon was 9% in 2008, which was increased especially compare to 2000. More active governmental approaches for control and prevention of atopic dermatitis for children are recommended. Further studies are needed for more accurate estimation of the prevalence of AD in Korea including different regional and age population.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.619-621
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• 2002

In this paper, AC reactor for PWM converter using the metal powder is introduced. Metal powder AC reactor was developed to substitute conventional iron core typed AC reactor in the PWM converter application. The characteristics of the metal powder AC reactor are analyzed and tested. A new reactor has reduced switching noise and loss.