• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2005년도 추계학술발표회
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• pp.719-720
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• 2005

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1999년도 추계학술발표회요약집
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• pp.221.1-221
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• 1999

• 한국식물병리학회지
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• 제2권3호
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• pp.158-164
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• 1986

Fusarium oxysporum f. sp. fragariae에 의한 딸기 시들음병에 감염된 딸기 식물의 병태조직학적 특징을 광학현미경으로 조사한 결과 자연 또는 인공 감염된 뿌리, 관부, 잎자루 및 포복지의 도관내에는 본 병균의 균사와 대형, 소형 분생포자가 관찰되었으며, 이들 균체에 의한 도관의 폐쇄와 유관속내에 형성된 강(Cavity)이 관찰되었으나 다른 분화형에서 볼 수 있는 도관유조직의 비대현상, 분충체 및 pectin 물질에 의한 도관폐쇄는 관찰할 수 없었다. 따라서 딸기 시들음병의 위조발생은 균체에 의한 도관의 폐쇄가 중요한 요인으로 생각되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.70-77
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• 2010

In this paper, a case study of drivability and bearing capacity of large diameter steel pipe piles at PTT LNG site in Thailand is introduced. The LNG facilities were designed to be founded on steel pipe pile foundations driven into the weathered rock formation overlaid by sand layers. The drivability analyses of open ended pipe piles were carried out using GRL WEAP program and the bearing capacities of the piles were estimated. Dynamic load tests were performed to evaluate end bearing resistance, and it is shown that the measured end bearing resistance is smaller than the calculated end bearing because the plugging does not develop sufficiently in case of large diameter pipe piles.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1186-1191
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• 2003

The 40% of wall criterion, which is generally used for the plugging of steam generator tubes, may be applied only to a single crack. In the previous study, a total of 9 failure models were introduced to estimate the local failure of the ligament between cracks and the optimum coalescence model of multiple collinear cracks was determined among these models. It is, however, known that parallel axial cracks are more frequently detected during an in-service inspection than collinear axial cracks. The objective of this study is to determine the plastic collapse model which can be applied to the steam generator tube containing two parallel axial through-wall cracks. Nine previously proposed local failure models were selected as the candidates. Subsequently interaction effects between two adjacent cracks were evaluated to screen them. Plastic collapse tests for the plate with two parallel through-wall cracks and finite element analyses were performed for the determination of the optimum plastic collapse model. By comparing the test results with the prediction results obtained from the candidate models, a plastic zone contact model was selected as an optimum model.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.110.1-110.1
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• 2011

최근 식물성 기름으로부터 생산된 바이오디젤의 보급이 활발해지면서, 그 원료의 안정적 확보에 대한 어려움과 원료가격 상승의 문제점이 발생하고 있다. 이러한 문제점을 극복하기 위한 대안으로 다양한 종류의 기름이 검토되고 있으며, 그 중 하나가 축산 폐유지를 이용한 바이오디젤의 생산이다. 그러나 축산 폐유지로부터 생산된 바이오디젤은 저온유동성이 열악하여 개선이 필요하다. 축산 폐유지 바이오디젤의 저온필터막힘점은 $6{\sim}8^{\circ}C$로 국내 동절기 품질 기준 $0^{\circ}C$ 이하를 만족하지 못한다. 본 연구에서는 축산 폐유지로부터 생산된 바이오디젤의 열악한 저온특성을 개선하기 위해 저온필터막힘점 개선 첨가제 6종을 사용하여 각각의 첨가제 혼합에 의한 저온유동성 개선 효과를 분석하였다. 각각의 첨가제를 1,000 ~ 5,000ppm 범위에서 폐돈지 및 폐우지 바이오디젤에 첨가하였다. 그 결과, Wintron을 제외한 나머지 첨가제는 폐돈지 바이오디젤의 저온필터막힘점을 최저 $0^{\circ}C$까지 개선할 수 있었다. 하지만 폐우지 바이오디젤의 경우, 첨가제에 의한 저온유동성 개선의 효과는 매우 적었다.

• Nuclear Engineering and Technology
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• 제36권4호
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• pp.316-326
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• 2004

The $40\%$ of wall criterion, which is generally used for the plugging of steam generator tubes, is applied only to a single crack. In a previous study, a total number of 9 failure models were proposed to estimate the local failure of the ligament between cracks, and the optimum coalescence model of multiple collinear cracks was determined among these models. It is, however known that parallel axial cracks are more frequently detected than collinear axial cracks during an in-service inspection. The objective of this study is to determine the plastic collapse model that can be applied to steam generator tubes containing two parallel axial through-wall cracks. Three previously proposed local failure models were selected as the candidates. Subsequently, the interaction effects between two adjacent cracks were evaluated to screen them. Plastic collapse tests for the plate with two parallel through-wall cracks and finite element analyses were performed to determine the optimum plastic collapse model. By comparing the test results with the prediction results obtained from the candidate models, a COD base model was selected as an optimum model.

• Nuclear Engineering and Technology
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• 제36권4호
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• pp.327-337
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• 2004

It is commonly required that tubes with defects exceeding $40\%$ of wall thickness in depth should be plugged; however, this criterion is too conservative for some locations and for some types of defects. Many studies have been done with the aim of developing an alternative plugging criteria, and these studies have shown that steam generator tubes with a certain range of axial through-wall cracks could remain in service without any safety or reliability problems. However, these studies have been limited, thus far, to consideration of single cracked tubes, necessitating a study on multiple cracks, which are commonly found. A crack coalescence model applicable to steam generator tubes with two collinear axial through-wall cracks was proposed in the previous study. In this paper, the investigation is extended to the parallel axial cracks spaced in a circumferential direction, because parallel axial cracks are more frequently detected during in-service inspections than collinear axial cracks. Interaction effects between two parallel cracks are evaluated by performing elastic and elastic-plastic finite element analyses.

• 대한기계학회논문집A
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• 제28권11호
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• pp.1813-1821
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• 2004

Until now, the 40% of wall thickness criterion, which is generally used for the plugging of steam generator tubes, has been applied only to a single cracked geometry. In the previous study by the authors, a total number of 9 local failure prediction models were introduced to estimate the coalescence load of two collinear through-wall cracks and, then, the reaction force model and plastic zone contact model were selected as the optimum ones. The objective of this study is to estimate the coalescence load of two collinear through-wall cracks in steam generator tube by using the optimum local failure prediction models. In order to investigate the applicability of the optimum local failure prediction models, a series of plastic collapse tests and corresponding finite element analyses for two collinear through-wall cracks in steam generator tube were carried out. Thereby, the applicability of the optimum local failure prediction models was verified and, finally, a coalescence evaluation diagram which can be used to determine whether the adjacent cracks detected by NDE coalesce or not has been developed.

• 펄프종이기술
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• 제32권1호
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• pp.19-25
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• 2000

In Condebelt press drying system, the temperature difference between top and bottom plate of Condebelt transfers water to bottom side, Fine fibers, stickies , ink , and various inorganic materials are also migrated to the fine wire located at the bottom plate by highly pressurized moisture flow. As a result, the fine wire contaminated by plugging of these fine and sticky materials can cause many problems such as blistering or partial crushing of paper. The contaimination of fine wire leads to a deterioroated strength together with uneven physical properties of paper. In this paper, froth-flotatiion method, which is commonly used in the field of ONP recycling process, were adopted to separate the contaminants in KOCC as a new fiber fractionation method. Standard deviation of paper strength and brighteness decreased of Condebelt fine wire were measured to investigate the effect of contaminants removal . The standard deviations of paper strength obtained from the flotated accept were not dependent on the number of condebelt press drying . However, in the case of untreated KOCC, the standard deviations were increased as press drying repeated. This indicates that the contaminant gives uneven physical properties to the paper by wire plugging . Optical and SEM images clearly illustrate the effect of contaminants on the wire condition.