• Journal of Ginseng Research
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• 제26권3호
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• pp.151-158
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• 2002

Ginseng (Panax quinquefolius L.) has become one of the most valuable herb crops grown in North America. However, traditional cropping practices are favourable to disease and significant losses due to root disease are common, despite frequent use of fungicides. Seedlots are often contaminated with pathogens, however, little is known about the causes of seed decay and the role of seed pathogens as incitants of root rots. It was shown that both Fusarium spp. and Cylindrocarpon destructans were able to rot seeds and that C. destructans was more virulent than Fusarium spp. on seedling roots. A modified rose bengal agar MRBA) medium (1 g KH$_2$PO$_4$; 0.5 g MgSO$_4$; 50 mg rose bengal; 10 g dextrose; 5 g Bacto peptone; 15 g Bacto agar; 30 mg streptomycin sulfate; 250 mg ampicillin; 10 mg rifampicin; 500mg pentachloronitrobenzene; 500 mg dicloran; and 1 L distilled water) was superior to potato dextrose agar in detecting C. destuctans in diseased roots. Isolation of C. destructans from diseased seedlings arising from seeds sown in replant soil supported the hypothesis that this pathogen is a cause of ginseng replant failure in North America.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.103-108
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• 2008

Purpose: Studies reported controversial results about prognosis of root resection with 0%-38% failure rate. The purpose of this study is to consider clinical efficacy of root resection. Materials and Methods: This study reported three cases of root resection which were performed on different sites. In first case, lower right first molar showed pus discharge and 7 mm of probing pocket depth. It was diagnosed as fracture of mesial root. Hemisection of mesial root was performed. In second case, upper right first molar showed severe bone loss on disto-buccal root and 7 mm of probing pocket. Resection of disto-buccal root was performed In third case, lower left second molar showed severe bone loss on distal root including apex and 15mm of probing pocket depth. Hemisection of distal root was performed. Result: In these three cases of root resection, compromised molars were treated successfully and conserved. Conclusion: Root resection is a successful procedure treating compromised multi-rooted teeth and conserving teeth when proper case selection is performed.

• 대한기계학회논문집A
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• 제36권3호
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• pp.297-304
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• 2012

블레이드의 성능 평가를 위하여 실제 사용 환경과 근접한 하중 모사에 따른 이축 하중의 필요성이 제기되고 있으며, 본 본문에서는 이러한 이축 하중에 따른 블레이드의 거동을 해석하였다. 100kW급 풍력 블레이드를 대상으로 하였으며, ANSYS를 사용하여 정적거동을 분석하였다. 정적거동은 파손해석과 좌굴거동으로 분석하였으며, 파손 평가는 Puck이 제안한 파손 방정식을 이용하여 섬유 파손과 섬유간 파손 기준을 검토하였다. 이축하중의 하중비가 증가함에 따라 루트부 단면이 변하는 후연부와 루트에서 Z+ 3300~3600인 지점에서 응력이 상대적으로 크게 나타났다. 또한 이축 하중비가 증가함에 따라 블레이드 좌굴 지점이 루트부 쪽으로 이동되고 있음을 확인하였다. 따라서 블레이드의 사용 신뢰성을 검증하기 위해서는 이축 하중에 의한 시험이 요구되고 있음을 본 해석을 통해서 확인하였다.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.572-572
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• 2001

The meaning of obturating root canal is to substitute an inert filling materials in the prepared canal space in order to eliminate all avenues of leakage from the oral cavity or periradicular tissue into root canal system. Inadequate obturation induce the infiltration of periapical tissue fluids, which provide materials for growth of microorganisms or localization of bacteria, into dead space of loosely filled canal. Most parts of endodontic failure is attributed to inadequate obturation of root canal system.(omitted)

• 한국항공운항학회지
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• 제26권2호
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• pp.68-75
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• 2018

A flare from an Air Force fighter was abnormally dispensed during the landing. To determine the cause of the abnormal dispensing, fracture analysis, signal analysis and reproduction experiments based on physics of failures were performed. The primary cause of the failure was analyzed to be due to an intermittent fault of an internal circuit card in the AN/ALE-40 chaff/flare dispenser by a broken lid of a capacitor, and the root cause which had derived the primary cause was considered to be an improper handling during the domestic maintenance which were changed from the overseas maintenance due to the DMSMS problem. Therefore, the overall process of the maintenance capability development system was reviewed and alternative ways that considers maintenance error decision aid(MEDA) for system improvement were suggested to prevent further failures.

• 한국신뢰성학회지:신뢰성응용연구
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• 제4권2호
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• pp.121-131
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• 2004

HALT (Highly Accelerated Life Test) was performed to improve the reliability by removing the potential failure for newly developing PCB used for the vibration condition from 2OHz to 2OOHz. During HALT, it is found that the lead of Al electrolytic capacitor of SMD type is detached from PCB. As the result for the failure analysis and FEM (Finite Element Method), it is clarified that the root cause for this failure is the improper attachment of an Al electrolytic capacitor on PCB by the mistake of a PCB design. HALT was performed in previous condition to verify the failure analysis after molding an epoxy resin to overcome the PCB design mistake and it is not observed the same failure. Therefore, it is assumed that the same failure in field will be not occurred by the proper implementation.

• 대한치과의사협회지
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• 제57권7호
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• pp.392-402
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• 2019

The most important part of everyday root canal treatment is diagnosis about the morphology of tooth, root and root canal. Usually this procedure is performed by visual examination and radiographic (panoramic/periapical) examination. However, 2-dimentional radiography has several limitations such as imposition of anatomic structures including buccal/lingual root canals and distortion of images. Recently, owing to the increased interest in dental implant and affordable cost of CBCT equipment, CBCT has been introduced widely in local dental clinics. CBCT is characterized by their lower radiation dose and shorter exposure time than conventional CT scan, and ability of 3-dimentional reconstruction of the dento-alveolar structure. Also in endodontic field, the data from CBCT could be very helpful in diagnosing complex root canal anatomy, apical periodontitis, cause of failure and in determining treatment plan. However, there are some limitations such as radiation dose and artifact. Therefore, clinicians should know about indication, advantages and limitations of CBCT, and properly use it for successful root canal treatment to save the natural teeth.

• Geomechanics and Engineering
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• 제9권1호
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• pp.115-124
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• 2015

Determination of mobilized shear strength parameters (that identify stresses on the failure plane) is required for analyzing the stability by limit equilibrium method. Generalized Hoek-Brown (GHB) and Mohr-Coulomb (MC) failure criteria are usually used for obtaining stresses on the plane of failure. In the present paper, the applicability of these criteria for determining the stresses on failure plane is investigated. The comparison is based on stresses on the real failure plane which are obtained from the Mohr stress circle. To do so, 18 sets of data (consist of principal stresses and angle of failure plane) presented in the literature are used. In addition, the values account for (VAF) and the root mean square error (RMSE) indices were calculated to check the determination performance of the obtained results. Values of VAF and RMSE for the normal stresses on the failure plane evaluated from MC are 49% and 31.5 where for GHB are 55% and 30.5, respectively. Also, for the shear stresses on failure plane, they are 74% and 36 for MC, 76% and 34.5 for GHB. Results show that the obtained stresses and angles of failure plane for each criterion differ from real ones, but GHB results are closer to the empirical results. Also, it is inferred that results are affected by the failure envelope not real failure plane. Therefore, obtained shear strength parameters are not mobilized. Finally, a multivariable regressed relation is presented for determining the stresses on the failure plane.

• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2003년도 제120회 추계학술대회 제 5차 한ㆍ일 치과보존학회 공동학술대회
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• pp.606-606
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• 2003

There have been many studies that have evaluated success and failure of endodontic treatment (Nair, Sjogren), but there is remarkably limited information concerning the specific microorganisms that are involved in the teeth with treatment failure. Microorganisms that survive root canal treatment to cause a persistent infection must possess specific characteristics to avoid the host defense. These can be broadly classified as; 1. Sequestration：A physical barrier between the microbe and the host. 2. Cellular evasion：Microorganisms avoid leukocyte dependent antibacterial mechanisms. 3. Humoral evasion：Extracellular bacteria avoid the hosts antibodies and complement.(omitted)

• 디지털융복합연구
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• 제15권8호
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• pp.69-83
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• 2017

본 연구의 목적은 갤럭시노트7의 예를 들어 신제품의 실패를 시스템 안전분석 기법을 활용해 체계적으로 분석하는 것이다. 이러한 분석을 통해 제품실패의 근본적인 원인을 찾고 그 원인으로 발생하는 문제를 해결함으로써 사건재발을 방지하는데 도움이 되는 정보를 제공하고자 한다. 이를 위해 제품실패를 단순히 기술적 실패로 바라보는 것이 아니라 제품개발과 경영관리가 포함된 하나의 통합 시스템으로 바라보며, 그에 대한 실패의 근본적인 원인들을 분석할 필요가 있다. 이러한 관점을 갖고 시스템 안전분석 기법인 근본원인분석과 고장수목분석을 활용해 갤럭시노트7의 제품실패 원인을 분석하였다. 이러한 분석과정을 통해 배터리 과열이라는 피상적인 기술적 문제와 더불어 경쟁사와의 지나친 경쟁에 따른 무리한 제품출시와 성과주의와 같은 제품개발 및 경영관리에서의 문제에도 많은 관심을 기울일 필요가 있음을 파악하였다. 또한 통합 시스템적 관점을 견지한다면 제품실패의 원인을 분석하는데 근본원인분석과 고장수목분석이 유용하게 이용될 수 있음을 확인할 수 있었다.