• Corrosion Science and Technology
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• 제3권3호
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• pp.98-101
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• 2004

The corrosion behavior of Al-Fe coatings was studied in the wet-seal atmosphere of molten carbonate fuel cells (MCFC). Fe-8Al, Fe-16Al, Fe-25Al, Fe-36Al, and Fe-70Al (in at.%) specimens were tested in Li/K carbonate at $650^{\circ}C$ by a single cell test and an immersion test. In general, the corrosion resistance of the Al-Fe coatings was enhanced due to the formation of a protective $LiAlO_2$ layer. However, when the Al-Fe coatings didn't have sufficient content of aluminum enough for maintaining the protective layer, the corrosion resistance of the Al-Fe coatings was severely degraded by the growth of non-protective scales like $LiAlO_2$. The test results revealed that the aluminum contents in the coatings should be higher than 25 at.% in order to form and maintain the protective $LiAlO_2$ layers.

• 한국항공우주학회지
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• 제45권1호
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• pp.46-53
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• 2017

본 논문에서는 회전익 항공기의 조종입력과 지상 활주 속도를 바탕으로 해석을 통하여 전선절단기 길이를 제시하였다. 항공기의 안전을 위해서 적용되는 전선절단기가 적절한 길이로 선정되지 않을 경우 블레이드와 충돌가능성 생기거나 전선에 의해서 사고가 발생할 수 있다. 본 연구를 위해서 개발에서 사용된 조종입력을 분석하여 지상 활주에 필요한 조종입력 조건을 설정하였다. 이를 바탕으로 20, 40, 60 kts 지상 활주 속도별로 해석을 통하여 블레이드와 전선절단기 충돌 가능성을 검토하였다. 이 후, 이 결과를 항공기 모사시험 결과와 비교하여 해석결과의 적절성을 확인하였다. 최종적으로 지상 활주 간 모든 조종입력 범위에 대해 충돌을 피하기 위한 전선절단기 축소 길이와 이 경우 공중비행 시 생기는 비보호구역의 증가량을 동시에 제시하였다.

• 한국의류산업학회지
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• 제25권2호
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• pp.248-254
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• 2023

This study aims to measure the skin rigidity of different facial areas among Koreans and propose guidelines for each area's skin rigidity that can be applied with a facial robot for testing respiratory protective devices. The facial skin rigidity of 40 participants, which included 20 men and 20 women, aged 20 to 50, was analyzed. The rigidity measurement was conducted in 13 facial areas, including six areas in contact with the mask and seven non-contact areas, by referring to the facial measurement guidelines of Size Korea. The facial rigidity was measured using the Durometer RX-1600-OO while in a supine position. The measurement procedure involved contacting the durometer vertically with the reference point, repeating the measurement of the same area five times, and using the average of three values whose variability was between 0.4 and 4.2 Shore OO. The rigidity data analysis used precision analysis, descriptive statistics analysis, and mixed-effect ANOVA. The analysis confirmed the rigidity of the 13 measurement areas, with the highest rigidity of the face being at the nose and forehead points, with values of 51.2 and 50.8, respectively, and the lowest rigidity being at the chin and center of the cheek points, with values of 19.2 and 20.7, respectively. Significant differences between gender groups were observed in four areas: the tip of the nose, the point below the chin, the area below the lower jaw, and the inner concha.

• Tribology and Lubricants
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• 제13권3호
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• pp.56-62
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• 1997

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindle. High speed spindles require non-contact type sealing mechanism. In this study, an optimum seal design to minimize leakage is concerned in the aspect of flow control. This paper categorizes geometries of mostly used non-contact type seals and analyzes each leakage characteristics to minimize a leakage on sealing area. Effect of minimum clearance and its position are considered according to variation of detail geometry. The estimation of non-leaking property is determined by amount of pressure drop in the leakage path assuming constant leakage flow. To simulate an oil jet or oil mist type high speed spindle lubrication, the working fluid is regarded as two phases that are mixed flow of oil phase and air phase. Both of the turbulence and the compressible flow model were introduced in CFD(Computational Fluid Dynamics) analysis. Design parameters has been induced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted.

• 한국표면공학회지
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• 제46권3호
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• pp.111-115
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• 2013

To study the encapsulation method for large-area organic light emitting devices (OLEDs), OLED of ITO / 2-TNATA / NPB / $Alq_3$:Rubrene / $Alq_3$ / LiF / Al structure was fabricated, which on $Alq_3$/LiF/Al as protective layer of OLED was deposited to protect the damage of OLED, and subsequently it was encapsulated using attaching film and flat glass. The current density and luminance of encapsulated OLED using attaching film and flat glass has similar characteristics compared with non-encapsulated OLED when thickness of Al as a protective layer was 1200 nm, otherwise power efficiency of encapsulated OLED was better than non-encapsulated OLED. Encapsulation process using attaching film and flat glass did not have any effects on the emission spectrum and the Commission International de L'Eclairage (CIE) coordinate. The lifetime of encapsulated OLED using attaching film and flat glass was 287 hours in 1200 nm Al thickness, which was increased according to thickness of Al protective layer, and was improved 54% compared with 186 hours in same Al thickness, lifetime of encapsulated OLED using epoxy and flat glass. As a result, it showed the improved efficiency and the long lifetime, because the encapsulation method using attaching film and flat glass could minimize the impact on OLED caused through UV hardening process in case of glass encapsulation using epoxy.

• Journal of Radiation Protection and Research
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• 제39권2호
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• pp.109-117
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• 2014

방사선비상계획은 원자력시설에 대한 사고해석을 통해 산출한 방사선원항과 기상자료에 근거한 선량평가 결과를 기초로 비상계획이 필요한 거리를 산출하고, 비상계획이 필요한 거리 내에 거주하고 있는 거주민에 대한 옥내대피, 소개, 갑상선방호 등의 보호조치 계획을 수립하는 방식으로 이루어진다. 본 연구에서는 연구용원자로 '하나로'에서 가상할 수 있는 최대사고 조건 하에서 부지내외 거주자에 대한 보호조치 전 후의 선량변화를 1년간 기상자료에 기초하여 확률론적으로 평가하고, 국제방사선방호위원회의 2007년 권고에서 제시한, 비상피폭상황에서 보호조치 이후 잔여선량으로 정의된 참조준위 개념을 사용하여, 최적의 보호조치 유형을 도출하였다. 하나로의 경우 최대 가상사고시 최적의 보호조치 유형은 반경 300 m 이내 거주자 소개, 반경 800 m 이내 거주자 옥내대피로 평가되었으며, 갑상선방호는 반경 600 m 이내 거주자에 국한하여 해당되는데 이 지역 거주자가 소개 또는 옥내대피시는 방사능방재요원 외에 필요가 없는 것으로 평가되었다.

• 한국재난정보학회 논문집
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• 제18권2호
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• pp.269-279
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• 2022

연구목적: 본 연구의 목적은 건설현장의 재해 예방을 위해 딥러닝기반의 개인보호구 검출 모델을 개발하고, 실제 건설현장에 적용하여 분석하는 것이다. 연구방법: 본 연구의 수행 방법은 실제 환경의 데이터를 구축하고, 개발된 개인보호구 검출 모델을 적용하였다. 개인보호구 검출 모델은 크게 근로자 검출 및 개인보호구 착용 분류 모델로 구성되어 있다. 근로자 검출 모델은 딥러닝 기반의 알고리즘을 실제 현장에서 획득한 데이터셋을 구축하여 학습 및 근로자를 검출하였고, 개인보호구 착용 분류 모델은 앞단에서 추출된 근로자 검출영역에서 학습된 개인보호구 검출 알고리즘을 적용하였다. 구축된 모델의 검증을 위해 건설현장 3곳에서 획득된 데이터를 통해 실험결과를 도출하였다. 연구결과: 데이터베이스 12,000장을 구축하여 정상검출 9,460장(78.8%), 오검출 1,468(12.2%), 미검출 1,072장(8.9%)으로 나타났으며 주요 원인은 영상에서의 객체 크기, 객체간 중첩(Occulusion), 객체 잘림, 그림자에 의한 오검출로 분류되었다. 결론: 개인보호구 검출모델은 현장 상황마다 다른 검출률을 확인할 수 있었고, 본 연구의 결과가 차후 현장적용을 위한 연구에 활용될 수 있을 것으로 여겨진다.

• 동의생리병리학회지
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• 제25권5호
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• pp.849-856
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• 2011

This study was investigated the protective effect of Cultivated Wild Ginseng(WG) on the toxicities induced by cyclophosphamide(CP) in mice. Twenty-four male BALB/c mice were divided into non-treated normal group(n=6), CP treated control group(n=6), CP+WG treated CP+WG group(n=6), WG treated WG group(n=6). CP(100 mg/kg of b.w., i.p) was injected at 0, 7 th, 14 th, 21 th, and 28 th day of the experiment respectively. WG(4.4 g/kg, i.p.) was administrated for 35days. Body and organ(heart, liver, kidney, testis) weight were measured. Histopathological examination on the organ(heart, liver, kidney, testis), morphometric analysis, and BrdU immunohistochemistry on the testis were performed. Body weight was decreased following CP administration. In contrast, such a decrease was significantly attenuated by WG administration. CPK and AST of CP+WG group were significantly decreased compared with CP group. Histopathologically, cross sectional area of testis and diameter of seminiferous tubule were significantly increased in CP+WG group compared with CP group. BrdU labelled cells in the seminiferous tubules were remarkably decreased in CP group. Whereas the number of seminiferous tubules labelled with BrdU in spermatogonia was increased by CP+WG administration. The obtained results suggest that WG has protective effect on CP-induced toxicity. This effect might be mediated through the supplementation of vital energy.

• 대한한방내과학회지
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• 제33권1호
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• pp.26-38
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• 2012

Objectives : The aim of this study was to investigate the effect of partial pyloric obstruction on body weight, gastric juice, gastric surface area and gastric edema in normal intact and/or vagotomized rats. Methods : Partial pyloric obstruction was performed by wrapping a non-absorbable rubber ring (D:6 mm, W:4 mm, T:1 mm) around the 1st portion of the duodenum. Vagotomy was performed by resecting the branches around the esophagogastric junction. Pre-post body weight differential, fasting gastric juice volume, gastric surface area and gastric edema were measured at 8 weeks and 20 weeks. For the effect of pyloric reperfusion the rubber ring was removed after 8 weeks and then an additional 12 weeks of observation was performed to the end of the 20-week experimental period. Results : In the initial 8 weeks observation, the effect of pylorus obstruction and/or vagotomy was significantly remarkable in the pylorus obstructed and vagotomized group; slowdown of weight gain, increase of fasting gastric juice volume, dilatation of gastric surface area and severe gastric edema were shown. In the remaining 12 weeks observation, the effect of reperfusion was significantly remarkable in the ring-removed antral dilated group; recovery of weight gain, decrease of gastric surface area and decrease of gastric edema were shown. However, gastric juice volume was not significantly different from the other group. Conclusions : Partial pyloric obstruction plays a aggravating role and the vagus nerve plays a protective role in body weight, gastric juice, gastric surface area, and gastric edema. Furthermore, pyloric valve dysfunction as an aggravating factor strengthened in defect of the vagus nerve. These results suggest that patients with both functional pyloric outlet obstruction and hypofunction of vagus nerve need to be diagnosed in good time and treated properly.

• 대한물리의학회지
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• 제1권1호
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• pp.139-146
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• 2006

Purpose : This study is to understand the reactive oxygen which is expected to be a causative factor of aging condition including dementia, atherosclerosis, even cancer. Methods : The reactive oxygen is generated usually when people do very hard exercise or is under severe stressful situation or in unhealthy environment and as a protective reaction to reactive oxygen, human body releases antioxidant enzyme systems like superoxide dismutase (SOD), catalase, glutathione peroxidase (GPX), glutathion-S-transferase (GST) and non-enzymetic antioxidant systems like glutathione, ascorbate, $\beta$-carotene, vitimin E. Results : Nowadays, we are getting more interested in the generation of reactive oxygen especially in the area of physical education, food and nutrition, alternative medicine etc. Conclusion : The study of reactive oxygen in patients with musculoskeletal disease is also required and among various physical therapeutic approaches, the method of general coordinative manipulation is considered more necessary.