• Progress in Superconductivity and Cryogenics
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• v.12 no.2
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• pp.21-24
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• 2010

This paper deals with numerical analysis on a high-$T_c$ superconducting (HTS) electrodynamic suspension (EDS) simulator according to the variation of the ground conductor conditions. Because the levitation force of EDS system is formed by the magnetic reaction between moving magnets and fixed ground conductors, the distribution of the magnetic flux on a ground conductor plays an important role in the determining of the levitation force level. The possible way to analyze HTS EDS system was implemented with 3D finite element method (FEM) tool. A plate type ground conductor generated stronger levitation force than ring type ground conductor. Although the outer diameter of Ring3 (335 mm) was larger than that of Ring2 (235 mm), the levitation force by Ring2 was stronger than that by Ring3. Considering the results of this paper, it is recommended that the magnetic flux distribution according to the levitation height and magnet current should be taken into account in the design of the ground conductors.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1159_1160
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• 2009

This paper presents the numerical simulation results on the supercodnucting electrodynamic suspension (EDS) simulator according to the variation of the ground conductor. The levitation force of the EDS system is formed by the reaction between the moving magnet and the fixed ground conductor. The possible way to simulate the EDS system were simulated in this paper by using finite element method (FEM). The static type simulator which consists of the fixed magnet, the fixed ground conductor and the ac current supply system. To verify the characteristics of high speed EDS system with the moving type simulator heavy, large and fast moving ground conductor is needed. The static type simulator can get the characteristics of the high speed EDS system by applying equivalent ac current to velocity, therefore it does not need large moving part. The static type EDS simulator, which can consist of an HTS magnet, the fixed ground conductor(s), an AC power supply and the measuring devices, also test the effect of the shape of the ground conductor easily. The plate type ground conductor made stronger levitation force than ring type ground conductor. Although the outer diameter 335 mm ring type ground conductor (Ring3) was larger than the outer diameter 235 mm ground conductor (Ring2), the levitation force by Ring2 was stronger than that by Ring3. From the calculation results on this paper, the consideration of the magnetic flux distribution according to the levitation height should be included in the process of the ground conductor design.

• The Korean Journal of Legal Medicine
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• v.40 no.2
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• pp.61-64
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• 2016

Ehlers-Danlos syndrome type IV (EDS IV) is a hereditary disorder of the connective tissue, characterized by easy bruising, thin skin with visible veins, and spontaneous rupture of the large arteries, uterus, or bowel. EDS IV is caused by mutations of the gene for type III procollagen (COL3A1), resulting in insufficient collagen production or a defect in the structure of collagen. EDS IV can have fatal complications such as the rupture of great vessels or organs, which can cause hemorrhaging and sudden unexpected death. Here, we report a case of a 43-year-old female who collapsed after a struggle with a neighbor. In this patient, the bifurcation of the bilateral common iliac artery ruptured, with no evidence of trauma, inflammation, or atherosclerosis. Genetic analysis of COL3A1 showed the presence of a c.2771G>A (p.Gly924Arg) mutation, which may be associated with EDS IV. The forensic pathologist should consider the possibility that the spontaneous visceral or arterial rupture was caused by EDS IV. Genetic analysis is not currently a routine procedure during autopsy. However, in this case, we suggest that the patient possibly had an underlying EDS IV condition, and we recommended family members of the deceased to seek genetic analysis and counseling.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.546-546
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• 2001

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.10a
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• pp.89-90
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• 2006

• 대한생식의학회:학술대회논문집
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• 2006.06a
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• pp.171.1-171.1
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• 2006

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2020.10a
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• pp.56-56
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• 2020

• Journal of Rhinology
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• v.25 no.2
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• pp.69-74
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• 2018

Background and Objectives: Sleep disturbances and excessive daytime sleepiness (EDS) are the major symptoms of obstructive sleep apnea (OSA). This study aimed to investigate clinical implications of insomnia and EDS in patients with OSA using the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS). Materials and Method: We evaluated 131 subjects with suspected OSA who were undergoing polysomnography (PSG) and performing the PSQI and ESS surveys. OSA was diagnosed when the apnea-hypopnea index was five or more. EDS was defined when ESS score was 11 points or higher. Detailed history and questionnaire were used to categorize insomnia. We compared clinical variables and PSG results in subgroups with or without insomnia and EDS. Results: There were no significant differences of PSQI and ESS score between controls and OSA. OSA with insomnia had significantly increased total score (p<0.001) and decreased total sleep time (p=0.001) and sleep efficiency (p=0.001) on the PSQI compared to those without insomnia. OSA with EDS showed significantly increased PSQI score (p=0.022) and decreased total sleep time (p=0.018) on PSG compared to those without EDS. Neither PSQI nor ESS score had a correlation with respiratory variables such as AHI and oxygen saturation. Total sleep time had a significant effect on both insomnia and EDS in patients with OSA. Conclusion: Decreased total sleep time had important effects on subjective symptoms of OSA and comorbid insomnia. Therefore, restoration of decreased sleep time is important in the management of OSA.

• Journal of Dental Rehabilitation and Applied Science
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• v.23 no.1
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• pp.79-84
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• 2007

Mineral Trioxide Aggregate(MTA) has been used in Endodontic treatment successfully for more than 10 years. But the high cost of MTA limits its use in endodontics in Korea. Recently many studies have been done to compare MTA and Portland cements. To investigate the chemical constitutions of MTA (Proroot MTA, Tulsa Dental), Gray Portland cement (Lafarge Halla cement), White Portland cement(Union corp), and fast setting cement (SSangyong cement), we performed SEM(scanning electron microscope)(S4700, Hitachi) examination and EDS(Energy dispersive spectrometry)(emax, Horiba) analysis. SEM examination and EDS analysis were committed to and performed in SNU DRI (Seoul National University Dental Research Institute). We found that particles of MTA were relatively round, uniform in size, and compactly packed compared to Portland cements. Chemical constitutions of MTA, GPC, WPC and FSC were similar. It was shown that MTA contains much BiO2 . MTA and WPC showed less heavy metals such as Fe and Mg compared to GPC and FSC. FSC showed remarkably high aluminum content.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.219-221
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• 2009

태양전지 어레이(PV-array)로부터 발전되는 DC 전력을 AC로 변환시켜 계통으로 발전시키는 역할을 하는 태양광 발전 시스템용 PCS의 스위칭 회로 Topology로는 일반적으로 3상 풀브리지 회로가 사용된다. 이러한 3상 풀브리지 회로 시스템의 수명예측을 위해 DC link 단의 커패시터의 커패시턴스를 계산하여 커패시턴스의 감소정도를 이용하여 전체 시스템의 수명을 예측하게 된다. 이러한 커패시터의 상태를 추정하기 위해서는 시스템을 정지시킨 후 커패시터를 분리하여 커패시턴스를 측정하는 방법, 특정 주파수의 전류(일반적으로 저주파)를 주입하고 주입한 전류의 주파수에 해당하는 전류 및 전압을 검출하여 capacitance 연산하는 방식등이 이용된다. 시스템을 정지시킨 후 커패시터를 분리하여 커패시턴스를 측정하는 방법은 번거로우며, 전류 주입을 이용한 방식은 불필요한 고조파 전류가 계통으로 침투하는 단점을 가진다. 그러므로 본 연구에서는 모듈타입 PCS 이용시 계통으로 고조파 침투가 없는 비침투 커패시턴스 계산 알고리즘을 제안한다.