• Journal of Mechanical Science and Technology
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• 제19권2호
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• pp.634-648
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• 2005

Performed here is a comparative assessment study for the probabilistic fracture mechanics approach of the pressurized thermal shock of the reactor pressure vessel. A round robin consisting of one prerequisite deterministic study and five cases for probabilistic approaches is proposed, and all organizations interested are invited. The problems are solved by the participants and their results are compared to issue some recommendation of best practices and to assure an understanding of the key parameters in this type of approach, like transient description and frequency, material properties, defect type and distribution, fracture mechanics methodology etc., which will be useful in the justification through a probabilistic approach for the case of a plant over-passing the screening criteria. Six participants from 3 organizations responded to the problem and their results are compiled and analyzed in this study.

• 대한기계학회논문집A
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• 제41권2호
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• pp.149-156
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• 2017

핵연료는 고도의 신뢰성과 안전성이 요구되는 구조물로서 손상유발 이물질이 유입되지 않도록 이물질여과 기구를 포함하고 있다. 핵연료의 이물질여과 성능은 건전성에 가장 중요한 영향 인자로 합리적이고 객관적으로 평가되어야 하는 지표이다. 본 연구에서는 표준 여과효율 성능지수를 수립하고자 가중평균을 이용하여 종합 이물질여과 효율 계산 방법을 제시하였다. 제안된 방법의 적합성을 확인하기 위해 대표 이물질 시편을 선정하고 이물질여과 실험을 통해 가중평균 여과 효율을 산술평균 여과 효율과 비교하였다. 가중평균법은 성능의 변별력을 강화하고자 이물질의 통과 가능 정도를 가중인자로 사용하였다. 부가적으로 이물질 시편의 크기와 여과 기구의 주요 치수에 따른 상용 핵연료의 여과 거동 분석을 수행하였다.

• 비파괴검사학회지
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• 제35권5호
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• pp.358-366
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• 2015

본 논문에서는 자주포, 전차 및 장갑차 등 지상궤도전투장비에 적용되는 비파괴검사 방안 검토 및 설계방안에 대해서 연구하였다. 비파괴검사 방안 중에서 지상궤도전투장비 비파괴검사자의 기량검증 요건은 미군규격에서 최초로 언급 되었으며, 이후 국내 지상궤도전투장비 무기 개발시 국방규격에도 적용되었다. 그러나 민 군 규격통일화사업을 통해 방산용 비파괴검사자의 자격은 기존 항공분야에서 적용중이던 NAS410이 항공/방산 공용규격으로 통합화 되었다. 본 연구에 대한 설계방안의 검증은 자주포에 사용되는 Al 단조품에 대해 최적설계된 액체침투탐상검사 방법을 적용하여 제품의 신뢰성 및 건전성을 확인하였다.

• Geomechanics and Engineering
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• 제23권5호
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• pp.441-454
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• 2020

The tunnel collapse, large deformation of surrounding rock, water and mud inrush are the major geological disasters in soft rock tunnel construction. Among them, tunnel collapse has the most serious impact on tunnel construction. Current research backed theories have certain limitations in identifying the collapse risk of soft rock tunnels. Examining the Zhengwan high-speed railway tunnel, eight soft rock tunnel collapse influencing factors were selected, and the combination of indicator weights based on the analytic hierarchy process and entropy weighting methods was obtained. The results show that the groundwater condition and the integrity of the rock mass are the main influencing factors leading to a soft rock tunnel collapse. A comprehensive fuzzy evaluation model for the collapse risk of soft rock tunnels is being proposed, and the real-time collapse risk assessment of the Zhengwan tunnel is being carried out. The results obtained via the fuzzy evaluation model agree well with the actual situation. A tunnel section evaluated to have an extremely high collapse risk and experienced a local collapse during excavation, verifying the feasibility of the collapse risk evaluation model. The collapse risk evaluation model proposed in this paper has been demonstrated to be a promising and innovative method for the evaluation of the collapse risk of soft rock tunnels, leading to safer construction.

• Journal of Radiation Protection and Research
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• 제24권4호
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• pp.225-230
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• 1999

본 연구는 이온화 방사선이 자주달개비 화분모세포의 미세핵 생성에 미치는 영향을 분석하여 선량-반응 관계를 수립하고자 수행되었다. 자주달개비의 화분모세포는 감수분열을 통하여 4개의 꽃가루로 발전되는 생식세포로서 분열과정 중에 방사선에 노출되면 염색체 조각이 분리되어 미세핵을 형성한다. 감마선 선량이 증가함에 따라 미세핵 생성률도 증가하였으며 특히 50 cGy까지의 선량범위에서 선량별 미세핵 생성률의 최대값은 뚜렷한 선량-반응관계를 보였다. 선량-반응 관계식을 통해 볼 때 1 cGy의 부가적 선량은 100 사분자당 최대 2개씩의 미세핵을 추가로 생성시키는 것으로 나타났다. 화분모세포 미세핵 생성률의 방사선 지표성은 생물학적 방사선량 감시를 위한 필수선결사항일 뿐 아니라 공해물질의 생체 위해성 검증, 수질과 토양의 건전성 평가 등에 대한 응용성을 갖고 있다.

• Ocean Systems Engineering
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• 제10권3호
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• pp.243-266
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• 2020

In-place analysis for offshore platforms is required to make proper design for new structures and true assessment for existing structures. In addition, ensure the structural integrity of platforms components under the maximum and minimum operating loads and environmental conditions. In-place analysis was carried out to verify the robustness and capability of structural members with all appurtenances to support the applied loads in either operating condition or storm conditions. A nonlinear finite element analysis is adopted for the platform structure above the seabed and the pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The SACS software is utilized to calculate the natural frequencies of the model and to obtain the response of platform joints according to in-place analysis then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have an important effect on the results of the in-place analysis behavior. The influence of the soil-structure interaction on the response of the jacket foundation predicts is necessary to estimate the loads of the offshore platform well and real simulation of offshore foundation for the in-place analysis. The result of the study shows that the in-place response investigation is quite crucial for safe design and operation of offshore platform against the variation of environmental loads.

• Earthquakes and Structures
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• 제18권4호
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• pp.407-421
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• 2020

In-place analysis for offshore platforms is essentially required to make proper design for new structures and true assessment for existing structures, in addition to the structural integrity of platforms components under the maximum and minimum operating loads when subjected to the environmental conditions. In-place analysis have been executed to check that the structural member with all appurtenance's robustness have the capability to support the applied loads in either storm or operating conditions. A nonlinear finite element analysis is adopted for the platform structure above the seabed and pile-soil interaction to estimate the in-place behavior of a typical fixed offshore platform. The SACS software is utilized to calculate the dynamic characteristics of the platform model and the response of platform joints then the stresses at selected members, as well as their nodal displacements. The directions of environmental loads and water depth variations have significant effects in the results of the in-place analysis behavior. The most of bending moment responses of the piles are in the first fourth of pile penetration depth from pile head level. The axial deformations of piles in all load combinations cases of all piles are inversely proportional with penetration depth. The largest values of axial soil reaction are shown at the pile tips levels (the maximum penetration level). The most of lateral soil reactions resultant are in the first third of pile penetration depth from pile head level and approximately vanished after that penetration. The influence of the soil-structure interaction on the response of the jacket foundation predicts that the flexible foundation model is necessary to estimate the force responses demands of the offshore platform with a piled jacket-support structure well.

• Preventive Nutrition and Food Science
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• 제9권1호
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• pp.79-84
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• 2004

Zinc intake and status of South Koreans from rural, urban and metropolitan areas were investigated. The dietary habits of 760 healthy male and female adult subjects with a mean age of 54 were assessed using a food frequency questionnaire and were verified using 24 h dietary recall. Daily Zn intakes for men and women were 7.4$\pm$5.4 mg and 7.0$\pm$5.4 mg, respectively, which were 62% and 70% of the Korean RDA. The phytate : zinc and phytate ${\times}$ calcium : zinc molar ratios were 38 and 398, respectively. Both the low intake of zinc and the high extremely phytate and phytate ${\times}$ calcium ratios with Zinc suggest that South Koreans may be at risk of zinc deficiency. Plasma zinc (86$\pm$61 $\mu\textrm{g}$/dL), urinary zinc (33$\pm$27 $\mu\textrm{g}$/dL) and plasma alkaline phosphatase (102$\pm$52 mU/mL) levels within the normal range did not however suggest marked Zinc deficiency in these subjects. However, conventional zinc biomarkers aye known to be unreliable for assessment of marginal zinc deficiency. Based on zinc intake alone, it is likely that at least a proportion of these subjects were marginally zinc deficient and the wider consumption of zinc rich, phytate deficient foods, particularly in rural areas, would be beneficial.

• 대한정형외과스포츠의학회지
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• 제12권1호
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• pp.16-23
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• 2013

슬관절의 다발성 인대 손상은 2개 또는 그 이상의 인대가 손상된 경우를 의미하고, 이 중 3개 또는 4개의 인대 파열이 일어나게 되면 대퇴골-경골 관절의 통합성이 파괴된 상태, 즉 슬관절의 탈구가 일어날 수 있다. 슬관절의 다발성 인대 손상이 있는 경우 혈관, 신경 상태를 단계적으로, 세심하게 평가하여야 하며 동맥 손상이 의심 시 지체하지 말고 응급 수술을 시행하여야한다. 슬관절의 다발성 인대 손상 치료에는 여러 이견이 있을 수 있으나 보존적 치료보다는 수술적 치료가, 지연 수술보다는 조기 수술이 권유되고, 전, 후방 십자 인대의 경우 재건술이, 후외방 인대의 경우 재건술이, 내측 측부 인대의 경우 봉합술 혹은 재건술이 권유되며, 다발성 인대 손상은 단일 인대 손상보다는 좀더 적극적인 치료가 요할 것으로 사료된다.

• 한국임상수의학회지
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• 제30권4호
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• pp.283-287
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• 2013

Canine skin is a highly dynamic organ that is constantly adapted to changes in its environment. It provides structural, sensory, immunologic, and physiologic functions and contributes an essential barrier function against potential environmental insults. We assessed the changes of canine skin hydration, pH, and protein contents by noninvasive method according to the frequency of application with canine commercial shampoo. Canine commercial shampoo was applied topically every other day, 5 days, and 8 days on different sites, respectively in 8 dogs. Saline-applied site was as a control. Skin hydration was increased and skin surface pH was decreased significantly in canine commercial shampoo-applied site every other day (p < 0.05). Also, skin protein concentration measured by D-squame$^{(R)}$ tape stripping method was increased significantly in canine commercial shampoo-applied site every other day (p < 0.05). There were alterations on every 5 days and 8 days, but not significantly. These results may be recognized that the frequent use of canine commercial shampoo cause abnormalities of the skin barrier function and alteration of stratum corneum integrity/cohesion. Consequently it was suggested that bathing the dog with canine commercial shampoo was appropriate every 5 or 8 days.